1 // SPDX-License-Identifier: GPL-2.0
3 * ring buffer based function tracer
5 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
8 * Originally taken from the RT patch by:
9 * Arnaldo Carvalho de Melo <acme@redhat.com>
11 * Based on code from the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 Nadia Yvette Chambers
15 #include <linux/ring_buffer.h>
16 #include <generated/utsrelease.h>
17 #include <linux/stacktrace.h>
18 #include <linux/writeback.h>
19 #include <linux/kallsyms.h>
20 #include <linux/seq_file.h>
21 #include <linux/notifier.h>
22 #include <linux/irqflags.h>
23 #include <linux/debugfs.h>
24 #include <linux/tracefs.h>
25 #include <linux/pagemap.h>
26 #include <linux/hardirq.h>
27 #include <linux/linkage.h>
28 #include <linux/uaccess.h>
29 #include <linux/vmalloc.h>
30 #include <linux/ftrace.h>
31 #include <linux/module.h>
32 #include <linux/percpu.h>
33 #include <linux/splice.h>
34 #include <linux/kdebug.h>
35 #include <linux/string.h>
36 #include <linux/mount.h>
37 #include <linux/rwsem.h>
38 #include <linux/slab.h>
39 #include <linux/ctype.h>
40 #include <linux/init.h>
41 #include <linux/poll.h>
42 #include <linux/nmi.h>
44 #include <linux/trace.h>
45 #include <linux/sched/clock.h>
46 #include <linux/sched/rt.h>
49 #include "trace_output.h"
52 * On boot up, the ring buffer is set to the minimum size, so that
53 * we do not waste memory on systems that are not using tracing.
55 bool ring_buffer_expanded;
58 * We need to change this state when a selftest is running.
59 * A selftest will lurk into the ring-buffer to count the
60 * entries inserted during the selftest although some concurrent
61 * insertions into the ring-buffer such as trace_printk could occurred
62 * at the same time, giving false positive or negative results.
64 static bool __read_mostly tracing_selftest_running;
67 * If a tracer is running, we do not want to run SELFTEST.
69 bool __read_mostly tracing_selftest_disabled;
71 /* Pipe tracepoints to printk */
72 struct trace_iterator *tracepoint_print_iter;
73 int tracepoint_printk;
74 static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
76 /* For tracers that don't implement custom flags */
77 static struct tracer_opt dummy_tracer_opt[] = {
82 dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
88 * To prevent the comm cache from being overwritten when no
89 * tracing is active, only save the comm when a trace event
92 static DEFINE_PER_CPU(bool, trace_taskinfo_save);
95 * Kill all tracing for good (never come back).
96 * It is initialized to 1 but will turn to zero if the initialization
97 * of the tracer is successful. But that is the only place that sets
100 static int tracing_disabled = 1;
102 cpumask_var_t __read_mostly tracing_buffer_mask;
105 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
107 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
108 * is set, then ftrace_dump is called. This will output the contents
109 * of the ftrace buffers to the console. This is very useful for
110 * capturing traces that lead to crashes and outputing it to a
113 * It is default off, but you can enable it with either specifying
114 * "ftrace_dump_on_oops" in the kernel command line, or setting
115 * /proc/sys/kernel/ftrace_dump_on_oops
116 * Set 1 if you want to dump buffers of all CPUs
117 * Set 2 if you want to dump the buffer of the CPU that triggered oops
120 enum ftrace_dump_mode ftrace_dump_on_oops;
122 /* When set, tracing will stop when a WARN*() is hit */
123 int __disable_trace_on_warning;
125 #ifdef CONFIG_TRACE_EVAL_MAP_FILE
126 /* Map of enums to their values, for "eval_map" file */
127 struct trace_eval_map_head {
129 unsigned long length;
132 union trace_eval_map_item;
134 struct trace_eval_map_tail {
136 * "end" is first and points to NULL as it must be different
137 * than "mod" or "eval_string"
139 union trace_eval_map_item *next;
140 const char *end; /* points to NULL */
143 static DEFINE_MUTEX(trace_eval_mutex);
146 * The trace_eval_maps are saved in an array with two extra elements,
147 * one at the beginning, and one at the end. The beginning item contains
148 * the count of the saved maps (head.length), and the module they
149 * belong to if not built in (head.mod). The ending item contains a
150 * pointer to the next array of saved eval_map items.
152 union trace_eval_map_item {
153 struct trace_eval_map map;
154 struct trace_eval_map_head head;
155 struct trace_eval_map_tail tail;
158 static union trace_eval_map_item *trace_eval_maps;
159 #endif /* CONFIG_TRACE_EVAL_MAP_FILE */
161 static int tracing_set_tracer(struct trace_array *tr, const char *buf);
163 #define MAX_TRACER_SIZE 100
164 static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
165 static char *default_bootup_tracer;
167 static bool allocate_snapshot;
169 static int __init set_cmdline_ftrace(char *str)
171 strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
172 default_bootup_tracer = bootup_tracer_buf;
173 /* We are using ftrace early, expand it */
174 ring_buffer_expanded = true;
177 __setup("ftrace=", set_cmdline_ftrace);
179 static int __init set_ftrace_dump_on_oops(char *str)
181 if (*str++ != '=' || !*str) {
182 ftrace_dump_on_oops = DUMP_ALL;
186 if (!strcmp("orig_cpu", str)) {
187 ftrace_dump_on_oops = DUMP_ORIG;
193 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
195 static int __init stop_trace_on_warning(char *str)
197 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
198 __disable_trace_on_warning = 1;
201 __setup("traceoff_on_warning", stop_trace_on_warning);
203 static int __init boot_alloc_snapshot(char *str)
205 allocate_snapshot = true;
206 /* We also need the main ring buffer expanded */
207 ring_buffer_expanded = true;
210 __setup("alloc_snapshot", boot_alloc_snapshot);
213 static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
215 static int __init set_trace_boot_options(char *str)
217 strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
220 __setup("trace_options=", set_trace_boot_options);
222 static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
223 static char *trace_boot_clock __initdata;
225 static int __init set_trace_boot_clock(char *str)
227 strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
228 trace_boot_clock = trace_boot_clock_buf;
231 __setup("trace_clock=", set_trace_boot_clock);
233 static int __init set_tracepoint_printk(char *str)
235 /* Ignore the "tp_printk_stop_on_boot" param */
239 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
240 tracepoint_printk = 1;
243 __setup("tp_printk", set_tracepoint_printk);
245 unsigned long long ns2usecs(u64 nsec)
252 /* trace_flags holds trace_options default values */
253 #define TRACE_DEFAULT_FLAGS \
254 (FUNCTION_DEFAULT_FLAGS | \
255 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \
256 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \
257 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \
258 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS)
260 /* trace_options that are only supported by global_trace */
261 #define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \
262 TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
264 /* trace_flags that are default zero for instances */
265 #define ZEROED_TRACE_FLAGS \
266 (TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK)
269 * The global_trace is the descriptor that holds the top-level tracing
270 * buffers for the live tracing.
272 static struct trace_array global_trace = {
273 .trace_flags = TRACE_DEFAULT_FLAGS,
276 LIST_HEAD(ftrace_trace_arrays);
278 int trace_array_get(struct trace_array *this_tr)
280 struct trace_array *tr;
283 mutex_lock(&trace_types_lock);
284 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
291 mutex_unlock(&trace_types_lock);
296 static void __trace_array_put(struct trace_array *this_tr)
298 WARN_ON(!this_tr->ref);
302 void trace_array_put(struct trace_array *this_tr)
304 mutex_lock(&trace_types_lock);
305 __trace_array_put(this_tr);
306 mutex_unlock(&trace_types_lock);
309 int call_filter_check_discard(struct trace_event_call *call, void *rec,
310 struct ring_buffer *buffer,
311 struct ring_buffer_event *event)
313 if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
314 !filter_match_preds(call->filter, rec)) {
315 __trace_event_discard_commit(buffer, event);
322 void trace_free_pid_list(struct trace_pid_list *pid_list)
324 vfree(pid_list->pids);
329 * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
330 * @filtered_pids: The list of pids to check
331 * @search_pid: The PID to find in @filtered_pids
333 * Returns true if @search_pid is fonud in @filtered_pids, and false otherwis.
336 trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
339 * If pid_max changed after filtered_pids was created, we
340 * by default ignore all pids greater than the previous pid_max.
342 if (search_pid >= filtered_pids->pid_max)
345 return test_bit(search_pid, filtered_pids->pids);
349 * trace_ignore_this_task - should a task be ignored for tracing
350 * @filtered_pids: The list of pids to check
351 * @task: The task that should be ignored if not filtered
353 * Checks if @task should be traced or not from @filtered_pids.
354 * Returns true if @task should *NOT* be traced.
355 * Returns false if @task should be traced.
358 trace_ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct *task)
361 * Return false, because if filtered_pids does not exist,
362 * all pids are good to trace.
367 return !trace_find_filtered_pid(filtered_pids, task->pid);
371 * trace_pid_filter_add_remove_task - Add or remove a task from a pid_list
372 * @pid_list: The list to modify
373 * @self: The current task for fork or NULL for exit
374 * @task: The task to add or remove
376 * If adding a task, if @self is defined, the task is only added if @self
377 * is also included in @pid_list. This happens on fork and tasks should
378 * only be added when the parent is listed. If @self is NULL, then the
379 * @task pid will be removed from the list, which would happen on exit
382 void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
383 struct task_struct *self,
384 struct task_struct *task)
389 /* For forks, we only add if the forking task is listed */
391 if (!trace_find_filtered_pid(pid_list, self->pid))
395 /* Sorry, but we don't support pid_max changing after setting */
396 if (task->pid >= pid_list->pid_max)
399 /* "self" is set for forks, and NULL for exits */
401 set_bit(task->pid, pid_list->pids);
403 clear_bit(task->pid, pid_list->pids);
407 * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
408 * @pid_list: The pid list to show
409 * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
410 * @pos: The position of the file
412 * This is used by the seq_file "next" operation to iterate the pids
413 * listed in a trace_pid_list structure.
415 * Returns the pid+1 as we want to display pid of zero, but NULL would
416 * stop the iteration.
418 void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
420 unsigned long pid = (unsigned long)v;
424 /* pid already is +1 of the actual prevous bit */
425 pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid);
427 /* Return pid + 1 to allow zero to be represented */
428 if (pid < pid_list->pid_max)
429 return (void *)(pid + 1);
435 * trace_pid_start - Used for seq_file to start reading pid lists
436 * @pid_list: The pid list to show
437 * @pos: The position of the file
439 * This is used by seq_file "start" operation to start the iteration
442 * Returns the pid+1 as we want to display pid of zero, but NULL would
443 * stop the iteration.
445 void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
450 pid = find_first_bit(pid_list->pids, pid_list->pid_max);
451 if (pid >= pid_list->pid_max)
454 /* Return pid + 1 so that zero can be the exit value */
455 for (pid++; pid && l < *pos;
456 pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
462 * trace_pid_show - show the current pid in seq_file processing
463 * @m: The seq_file structure to write into
464 * @v: A void pointer of the pid (+1) value to display
466 * Can be directly used by seq_file operations to display the current
469 int trace_pid_show(struct seq_file *m, void *v)
471 unsigned long pid = (unsigned long)v - 1;
473 seq_printf(m, "%lu\n", pid);
477 /* 128 should be much more than enough */
478 #define PID_BUF_SIZE 127
480 int trace_pid_write(struct trace_pid_list *filtered_pids,
481 struct trace_pid_list **new_pid_list,
482 const char __user *ubuf, size_t cnt)
484 struct trace_pid_list *pid_list;
485 struct trace_parser parser;
493 if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
497 * Always recreate a new array. The write is an all or nothing
498 * operation. Always create a new array when adding new pids by
499 * the user. If the operation fails, then the current list is
502 pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
504 trace_parser_put(&parser);
508 pid_list->pid_max = READ_ONCE(pid_max);
510 /* Only truncating will shrink pid_max */
511 if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max)
512 pid_list->pid_max = filtered_pids->pid_max;
514 pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
515 if (!pid_list->pids) {
516 trace_parser_put(&parser);
522 /* copy the current bits to the new max */
523 for_each_set_bit(pid, filtered_pids->pids,
524 filtered_pids->pid_max) {
525 set_bit(pid, pid_list->pids);
534 ret = trace_get_user(&parser, ubuf, cnt, &pos);
535 if (ret < 0 || !trace_parser_loaded(&parser))
543 if (kstrtoul(parser.buffer, 0, &val))
545 if (val >= pid_list->pid_max)
550 set_bit(pid, pid_list->pids);
553 trace_parser_clear(&parser);
556 trace_parser_put(&parser);
559 trace_free_pid_list(pid_list);
564 /* Cleared the list of pids */
565 trace_free_pid_list(pid_list);
570 *new_pid_list = pid_list;
575 static u64 buffer_ftrace_now(struct trace_buffer *buf, int cpu)
579 /* Early boot up does not have a buffer yet */
581 return trace_clock_local();
583 ts = ring_buffer_time_stamp(buf->buffer, cpu);
584 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
589 u64 ftrace_now(int cpu)
591 return buffer_ftrace_now(&global_trace.trace_buffer, cpu);
595 * tracing_is_enabled - Show if global_trace has been disabled
597 * Shows if the global trace has been enabled or not. It uses the
598 * mirror flag "buffer_disabled" to be used in fast paths such as for
599 * the irqsoff tracer. But it may be inaccurate due to races. If you
600 * need to know the accurate state, use tracing_is_on() which is a little
601 * slower, but accurate.
603 int tracing_is_enabled(void)
606 * For quick access (irqsoff uses this in fast path), just
607 * return the mirror variable of the state of the ring buffer.
608 * It's a little racy, but we don't really care.
611 return !global_trace.buffer_disabled;
615 * trace_buf_size is the size in bytes that is allocated
616 * for a buffer. Note, the number of bytes is always rounded
619 * This number is purposely set to a low number of 16384.
620 * If the dump on oops happens, it will be much appreciated
621 * to not have to wait for all that output. Anyway this can be
622 * boot time and run time configurable.
624 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
626 static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
628 /* trace_types holds a link list of available tracers. */
629 static struct tracer *trace_types __read_mostly;
632 * trace_types_lock is used to protect the trace_types list.
634 DEFINE_MUTEX(trace_types_lock);
637 * serialize the access of the ring buffer
639 * ring buffer serializes readers, but it is low level protection.
640 * The validity of the events (which returns by ring_buffer_peek() ..etc)
641 * are not protected by ring buffer.
643 * The content of events may become garbage if we allow other process consumes
644 * these events concurrently:
645 * A) the page of the consumed events may become a normal page
646 * (not reader page) in ring buffer, and this page will be rewrited
647 * by events producer.
648 * B) The page of the consumed events may become a page for splice_read,
649 * and this page will be returned to system.
651 * These primitives allow multi process access to different cpu ring buffer
654 * These primitives don't distinguish read-only and read-consume access.
655 * Multi read-only access are also serialized.
659 static DECLARE_RWSEM(all_cpu_access_lock);
660 static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
662 static inline void trace_access_lock(int cpu)
664 if (cpu == RING_BUFFER_ALL_CPUS) {
665 /* gain it for accessing the whole ring buffer. */
666 down_write(&all_cpu_access_lock);
668 /* gain it for accessing a cpu ring buffer. */
670 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
671 down_read(&all_cpu_access_lock);
673 /* Secondly block other access to this @cpu ring buffer. */
674 mutex_lock(&per_cpu(cpu_access_lock, cpu));
678 static inline void trace_access_unlock(int cpu)
680 if (cpu == RING_BUFFER_ALL_CPUS) {
681 up_write(&all_cpu_access_lock);
683 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
684 up_read(&all_cpu_access_lock);
688 static inline void trace_access_lock_init(void)
692 for_each_possible_cpu(cpu)
693 mutex_init(&per_cpu(cpu_access_lock, cpu));
698 static DEFINE_MUTEX(access_lock);
700 static inline void trace_access_lock(int cpu)
703 mutex_lock(&access_lock);
706 static inline void trace_access_unlock(int cpu)
709 mutex_unlock(&access_lock);
712 static inline void trace_access_lock_init(void)
718 #ifdef CONFIG_STACKTRACE
719 static void __ftrace_trace_stack(struct ring_buffer *buffer,
721 int skip, int pc, struct pt_regs *regs);
722 static inline void ftrace_trace_stack(struct trace_array *tr,
723 struct ring_buffer *buffer,
725 int skip, int pc, struct pt_regs *regs);
728 static inline void __ftrace_trace_stack(struct ring_buffer *buffer,
730 int skip, int pc, struct pt_regs *regs)
733 static inline void ftrace_trace_stack(struct trace_array *tr,
734 struct ring_buffer *buffer,
736 int skip, int pc, struct pt_regs *regs)
742 static __always_inline void
743 trace_event_setup(struct ring_buffer_event *event,
744 int type, unsigned long flags, int pc)
746 struct trace_entry *ent = ring_buffer_event_data(event);
748 tracing_generic_entry_update(ent, flags, pc);
752 static __always_inline struct ring_buffer_event *
753 __trace_buffer_lock_reserve(struct ring_buffer *buffer,
756 unsigned long flags, int pc)
758 struct ring_buffer_event *event;
760 event = ring_buffer_lock_reserve(buffer, len);
762 trace_event_setup(event, type, flags, pc);
767 void tracer_tracing_on(struct trace_array *tr)
769 if (tr->trace_buffer.buffer)
770 ring_buffer_record_on(tr->trace_buffer.buffer);
772 * This flag is looked at when buffers haven't been allocated
773 * yet, or by some tracers (like irqsoff), that just want to
774 * know if the ring buffer has been disabled, but it can handle
775 * races of where it gets disabled but we still do a record.
776 * As the check is in the fast path of the tracers, it is more
777 * important to be fast than accurate.
779 tr->buffer_disabled = 0;
780 /* Make the flag seen by readers */
785 * tracing_on - enable tracing buffers
787 * This function enables tracing buffers that may have been
788 * disabled with tracing_off.
790 void tracing_on(void)
792 tracer_tracing_on(&global_trace);
794 EXPORT_SYMBOL_GPL(tracing_on);
797 static __always_inline void
798 __buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
800 __this_cpu_write(trace_taskinfo_save, true);
802 /* If this is the temp buffer, we need to commit fully */
803 if (this_cpu_read(trace_buffered_event) == event) {
804 /* Length is in event->array[0] */
805 ring_buffer_write(buffer, event->array[0], &event->array[1]);
806 /* Release the temp buffer */
807 this_cpu_dec(trace_buffered_event_cnt);
809 ring_buffer_unlock_commit(buffer, event);
813 * __trace_puts - write a constant string into the trace buffer.
814 * @ip: The address of the caller
815 * @str: The constant string to write
816 * @size: The size of the string.
818 int __trace_puts(unsigned long ip, const char *str, int size)
820 struct ring_buffer_event *event;
821 struct ring_buffer *buffer;
822 struct print_entry *entry;
823 unsigned long irq_flags;
827 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
830 pc = preempt_count();
832 if (unlikely(tracing_selftest_running || tracing_disabled))
835 alloc = sizeof(*entry) + size + 2; /* possible \n added */
837 local_save_flags(irq_flags);
838 buffer = global_trace.trace_buffer.buffer;
839 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
844 entry = ring_buffer_event_data(event);
847 memcpy(&entry->buf, str, size);
849 /* Add a newline if necessary */
850 if (entry->buf[size - 1] != '\n') {
851 entry->buf[size] = '\n';
852 entry->buf[size + 1] = '\0';
854 entry->buf[size] = '\0';
856 __buffer_unlock_commit(buffer, event);
857 ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
861 EXPORT_SYMBOL_GPL(__trace_puts);
864 * __trace_bputs - write the pointer to a constant string into trace buffer
865 * @ip: The address of the caller
866 * @str: The constant string to write to the buffer to
868 int __trace_bputs(unsigned long ip, const char *str)
870 struct ring_buffer_event *event;
871 struct ring_buffer *buffer;
872 struct bputs_entry *entry;
873 unsigned long irq_flags;
874 int size = sizeof(struct bputs_entry);
877 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
880 pc = preempt_count();
882 if (unlikely(tracing_selftest_running || tracing_disabled))
885 local_save_flags(irq_flags);
886 buffer = global_trace.trace_buffer.buffer;
887 event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
892 entry = ring_buffer_event_data(event);
896 __buffer_unlock_commit(buffer, event);
897 ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
901 EXPORT_SYMBOL_GPL(__trace_bputs);
903 #ifdef CONFIG_TRACER_SNAPSHOT
904 void tracing_snapshot_instance(struct trace_array *tr)
906 struct tracer *tracer = tr->current_trace;
910 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
911 internal_trace_puts("*** snapshot is being ignored ***\n");
915 if (!tr->allocated_snapshot) {
916 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
917 internal_trace_puts("*** stopping trace here! ***\n");
922 /* Note, snapshot can not be used when the tracer uses it */
923 if (tracer->use_max_tr) {
924 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
925 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
929 local_irq_save(flags);
930 update_max_tr(tr, current, smp_processor_id());
931 local_irq_restore(flags);
935 * tracing_snapshot - take a snapshot of the current buffer.
937 * This causes a swap between the snapshot buffer and the current live
938 * tracing buffer. You can use this to take snapshots of the live
939 * trace when some condition is triggered, but continue to trace.
941 * Note, make sure to allocate the snapshot with either
942 * a tracing_snapshot_alloc(), or by doing it manually
943 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
945 * If the snapshot buffer is not allocated, it will stop tracing.
946 * Basically making a permanent snapshot.
948 void tracing_snapshot(void)
950 struct trace_array *tr = &global_trace;
952 tracing_snapshot_instance(tr);
954 EXPORT_SYMBOL_GPL(tracing_snapshot);
956 static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
957 struct trace_buffer *size_buf, int cpu_id);
958 static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
960 int tracing_alloc_snapshot_instance(struct trace_array *tr)
964 if (!tr->allocated_snapshot) {
966 /* allocate spare buffer */
967 ret = resize_buffer_duplicate_size(&tr->max_buffer,
968 &tr->trace_buffer, RING_BUFFER_ALL_CPUS);
972 tr->allocated_snapshot = true;
978 static void free_snapshot(struct trace_array *tr)
981 * We don't free the ring buffer. instead, resize it because
982 * The max_tr ring buffer has some state (e.g. ring->clock) and
983 * we want preserve it.
985 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
986 set_buffer_entries(&tr->max_buffer, 1);
987 tracing_reset_online_cpus(&tr->max_buffer);
988 tr->allocated_snapshot = false;
992 * tracing_alloc_snapshot - allocate snapshot buffer.
994 * This only allocates the snapshot buffer if it isn't already
995 * allocated - it doesn't also take a snapshot.
997 * This is meant to be used in cases where the snapshot buffer needs
998 * to be set up for events that can't sleep but need to be able to
999 * trigger a snapshot.
1001 int tracing_alloc_snapshot(void)
1003 struct trace_array *tr = &global_trace;
1006 ret = tracing_alloc_snapshot_instance(tr);
1011 EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1014 * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
1016 * This is similar to tracing_snapshot(), but it will allocate the
1017 * snapshot buffer if it isn't already allocated. Use this only
1018 * where it is safe to sleep, as the allocation may sleep.
1020 * This causes a swap between the snapshot buffer and the current live
1021 * tracing buffer. You can use this to take snapshots of the live
1022 * trace when some condition is triggered, but continue to trace.
1024 void tracing_snapshot_alloc(void)
1028 ret = tracing_alloc_snapshot();
1034 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1036 void tracing_snapshot(void)
1038 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
1040 EXPORT_SYMBOL_GPL(tracing_snapshot);
1041 int tracing_alloc_snapshot(void)
1043 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
1046 EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1047 void tracing_snapshot_alloc(void)
1052 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1053 #endif /* CONFIG_TRACER_SNAPSHOT */
1055 void tracer_tracing_off(struct trace_array *tr)
1057 if (tr->trace_buffer.buffer)
1058 ring_buffer_record_off(tr->trace_buffer.buffer);
1060 * This flag is looked at when buffers haven't been allocated
1061 * yet, or by some tracers (like irqsoff), that just want to
1062 * know if the ring buffer has been disabled, but it can handle
1063 * races of where it gets disabled but we still do a record.
1064 * As the check is in the fast path of the tracers, it is more
1065 * important to be fast than accurate.
1067 tr->buffer_disabled = 1;
1068 /* Make the flag seen by readers */
1073 * tracing_off - turn off tracing buffers
1075 * This function stops the tracing buffers from recording data.
1076 * It does not disable any overhead the tracers themselves may
1077 * be causing. This function simply causes all recording to
1078 * the ring buffers to fail.
1080 void tracing_off(void)
1082 tracer_tracing_off(&global_trace);
1084 EXPORT_SYMBOL_GPL(tracing_off);
1086 void disable_trace_on_warning(void)
1088 if (__disable_trace_on_warning)
1093 * tracer_tracing_is_on - show real state of ring buffer enabled
1094 * @tr : the trace array to know if ring buffer is enabled
1096 * Shows real state of the ring buffer if it is enabled or not.
1098 bool tracer_tracing_is_on(struct trace_array *tr)
1100 if (tr->trace_buffer.buffer)
1101 return ring_buffer_record_is_on(tr->trace_buffer.buffer);
1102 return !tr->buffer_disabled;
1106 * tracing_is_on - show state of ring buffers enabled
1108 int tracing_is_on(void)
1110 return tracer_tracing_is_on(&global_trace);
1112 EXPORT_SYMBOL_GPL(tracing_is_on);
1114 static int __init set_buf_size(char *str)
1116 unsigned long buf_size;
1120 buf_size = memparse(str, &str);
1122 * nr_entries can not be zero and the startup
1123 * tests require some buffer space. Therefore
1124 * ensure we have at least 4096 bytes of buffer.
1126 trace_buf_size = max(4096UL, buf_size);
1129 __setup("trace_buf_size=", set_buf_size);
1131 static int __init set_tracing_thresh(char *str)
1133 unsigned long threshold;
1138 ret = kstrtoul(str, 0, &threshold);
1141 tracing_thresh = threshold * 1000;
1144 __setup("tracing_thresh=", set_tracing_thresh);
1146 unsigned long nsecs_to_usecs(unsigned long nsecs)
1148 return nsecs / 1000;
1152 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
1153 * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that
1154 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
1155 * of strings in the order that the evals (enum) were defined.
1160 /* These must match the bit postions in trace_iterator_flags */
1161 static const char *trace_options[] = {
1169 int in_ns; /* is this clock in nanoseconds? */
1170 } trace_clocks[] = {
1171 { trace_clock_local, "local", 1 },
1172 { trace_clock_global, "global", 1 },
1173 { trace_clock_counter, "counter", 0 },
1174 { trace_clock_jiffies, "uptime", 0 },
1175 { trace_clock, "perf", 1 },
1176 { ktime_get_mono_fast_ns, "mono", 1 },
1177 { ktime_get_raw_fast_ns, "mono_raw", 1 },
1178 { ktime_get_boot_fast_ns, "boot", 1 },
1182 bool trace_clock_in_ns(struct trace_array *tr)
1184 if (trace_clocks[tr->clock_id].in_ns)
1191 * trace_parser_get_init - gets the buffer for trace parser
1193 int trace_parser_get_init(struct trace_parser *parser, int size)
1195 memset(parser, 0, sizeof(*parser));
1197 parser->buffer = kmalloc(size, GFP_KERNEL);
1198 if (!parser->buffer)
1201 parser->size = size;
1206 * trace_parser_put - frees the buffer for trace parser
1208 void trace_parser_put(struct trace_parser *parser)
1210 kfree(parser->buffer);
1211 parser->buffer = NULL;
1215 * trace_get_user - reads the user input string separated by space
1216 * (matched by isspace(ch))
1218 * For each string found the 'struct trace_parser' is updated,
1219 * and the function returns.
1221 * Returns number of bytes read.
1223 * See kernel/trace/trace.h for 'struct trace_parser' details.
1225 int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
1226 size_t cnt, loff_t *ppos)
1233 trace_parser_clear(parser);
1235 ret = get_user(ch, ubuf++);
1243 * The parser is not finished with the last write,
1244 * continue reading the user input without skipping spaces.
1246 if (!parser->cont) {
1247 /* skip white space */
1248 while (cnt && isspace(ch)) {
1249 ret = get_user(ch, ubuf++);
1258 /* only spaces were written */
1259 if (isspace(ch) || !ch) {
1266 /* read the non-space input */
1267 while (cnt && !isspace(ch) && ch) {
1268 if (parser->idx < parser->size - 1)
1269 parser->buffer[parser->idx++] = ch;
1274 ret = get_user(ch, ubuf++);
1281 /* We either got finished input or we have to wait for another call. */
1282 if (isspace(ch) || !ch) {
1283 parser->buffer[parser->idx] = 0;
1284 parser->cont = false;
1285 } else if (parser->idx < parser->size - 1) {
1286 parser->cont = true;
1287 parser->buffer[parser->idx++] = ch;
1288 /* Make sure the parsed string always terminates with '\0'. */
1289 parser->buffer[parser->idx] = 0;
1302 /* TODO add a seq_buf_to_buffer() */
1303 static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1307 if (trace_seq_used(s) <= s->seq.readpos)
1310 len = trace_seq_used(s) - s->seq.readpos;
1313 memcpy(buf, s->buffer + s->seq.readpos, cnt);
1315 s->seq.readpos += cnt;
1319 unsigned long __read_mostly tracing_thresh;
1321 #ifdef CONFIG_TRACER_MAX_TRACE
1323 * Copy the new maximum trace into the separate maximum-trace
1324 * structure. (this way the maximum trace is permanently saved,
1325 * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
1328 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1330 struct trace_buffer *trace_buf = &tr->trace_buffer;
1331 struct trace_buffer *max_buf = &tr->max_buffer;
1332 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1333 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1336 max_buf->time_start = data->preempt_timestamp;
1338 max_data->saved_latency = tr->max_latency;
1339 max_data->critical_start = data->critical_start;
1340 max_data->critical_end = data->critical_end;
1342 memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1343 max_data->pid = tsk->pid;
1345 * If tsk == current, then use current_uid(), as that does not use
1346 * RCU. The irq tracer can be called out of RCU scope.
1349 max_data->uid = current_uid();
1351 max_data->uid = task_uid(tsk);
1353 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1354 max_data->policy = tsk->policy;
1355 max_data->rt_priority = tsk->rt_priority;
1357 /* record this tasks comm */
1358 tracing_record_cmdline(tsk);
1362 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1364 * @tsk: the task with the latency
1365 * @cpu: The cpu that initiated the trace.
1367 * Flip the buffers between the @tr and the max_tr and record information
1368 * about which task was the cause of this latency.
1371 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1376 WARN_ON_ONCE(!irqs_disabled());
1378 if (!tr->allocated_snapshot) {
1379 /* Only the nop tracer should hit this when disabling */
1380 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1384 arch_spin_lock(&tr->max_lock);
1386 /* Inherit the recordable setting from trace_buffer */
1387 if (ring_buffer_record_is_set_on(tr->trace_buffer.buffer))
1388 ring_buffer_record_on(tr->max_buffer.buffer);
1390 ring_buffer_record_off(tr->max_buffer.buffer);
1392 swap(tr->trace_buffer.buffer, tr->max_buffer.buffer);
1394 __update_max_tr(tr, tsk, cpu);
1395 arch_spin_unlock(&tr->max_lock);
1399 * update_max_tr_single - only copy one trace over, and reset the rest
1401 * @tsk - task with the latency
1402 * @cpu - the cpu of the buffer to copy.
1404 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1407 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1414 WARN_ON_ONCE(!irqs_disabled());
1415 if (!tr->allocated_snapshot) {
1416 /* Only the nop tracer should hit this when disabling */
1417 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1421 arch_spin_lock(&tr->max_lock);
1423 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);
1425 if (ret == -EBUSY) {
1427 * We failed to swap the buffer due to a commit taking
1428 * place on this CPU. We fail to record, but we reset
1429 * the max trace buffer (no one writes directly to it)
1430 * and flag that it failed.
1432 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1433 "Failed to swap buffers due to commit in progress\n");
1436 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1438 __update_max_tr(tr, tsk, cpu);
1439 arch_spin_unlock(&tr->max_lock);
1441 #endif /* CONFIG_TRACER_MAX_TRACE */
1443 static int wait_on_pipe(struct trace_iterator *iter, bool full)
1445 /* Iterators are static, they should be filled or empty */
1446 if (trace_buffer_iter(iter, iter->cpu_file))
1449 return ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file,
1453 #ifdef CONFIG_FTRACE_STARTUP_TEST
1454 static bool selftests_can_run;
1456 struct trace_selftests {
1457 struct list_head list;
1458 struct tracer *type;
1461 static LIST_HEAD(postponed_selftests);
1463 static int save_selftest(struct tracer *type)
1465 struct trace_selftests *selftest;
1467 selftest = kmalloc(sizeof(*selftest), GFP_KERNEL);
1471 selftest->type = type;
1472 list_add(&selftest->list, &postponed_selftests);
1476 static int run_tracer_selftest(struct tracer *type)
1478 struct trace_array *tr = &global_trace;
1479 struct tracer *saved_tracer = tr->current_trace;
1482 if (!type->selftest || tracing_selftest_disabled)
1486 * If a tracer registers early in boot up (before scheduling is
1487 * initialized and such), then do not run its selftests yet.
1488 * Instead, run it a little later in the boot process.
1490 if (!selftests_can_run)
1491 return save_selftest(type);
1494 * Run a selftest on this tracer.
1495 * Here we reset the trace buffer, and set the current
1496 * tracer to be this tracer. The tracer can then run some
1497 * internal tracing to verify that everything is in order.
1498 * If we fail, we do not register this tracer.
1500 tracing_reset_online_cpus(&tr->trace_buffer);
1502 tr->current_trace = type;
1504 #ifdef CONFIG_TRACER_MAX_TRACE
1505 if (type->use_max_tr) {
1506 /* If we expanded the buffers, make sure the max is expanded too */
1507 if (ring_buffer_expanded)
1508 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
1509 RING_BUFFER_ALL_CPUS);
1510 tr->allocated_snapshot = true;
1514 /* the test is responsible for initializing and enabling */
1515 pr_info("Testing tracer %s: ", type->name);
1516 ret = type->selftest(type, tr);
1517 /* the test is responsible for resetting too */
1518 tr->current_trace = saved_tracer;
1520 printk(KERN_CONT "FAILED!\n");
1521 /* Add the warning after printing 'FAILED' */
1525 /* Only reset on passing, to avoid touching corrupted buffers */
1526 tracing_reset_online_cpus(&tr->trace_buffer);
1528 #ifdef CONFIG_TRACER_MAX_TRACE
1529 if (type->use_max_tr) {
1530 tr->allocated_snapshot = false;
1532 /* Shrink the max buffer again */
1533 if (ring_buffer_expanded)
1534 ring_buffer_resize(tr->max_buffer.buffer, 1,
1535 RING_BUFFER_ALL_CPUS);
1539 printk(KERN_CONT "PASSED\n");
1543 static __init int init_trace_selftests(void)
1545 struct trace_selftests *p, *n;
1546 struct tracer *t, **last;
1549 selftests_can_run = true;
1551 mutex_lock(&trace_types_lock);
1553 if (list_empty(&postponed_selftests))
1556 pr_info("Running postponed tracer tests:\n");
1558 tracing_selftest_running = true;
1559 list_for_each_entry_safe(p, n, &postponed_selftests, list) {
1560 ret = run_tracer_selftest(p->type);
1561 /* If the test fails, then warn and remove from available_tracers */
1563 WARN(1, "tracer: %s failed selftest, disabling\n",
1565 last = &trace_types;
1566 for (t = trace_types; t; t = t->next) {
1577 tracing_selftest_running = false;
1580 mutex_unlock(&trace_types_lock);
1584 core_initcall(init_trace_selftests);
1586 static inline int run_tracer_selftest(struct tracer *type)
1590 #endif /* CONFIG_FTRACE_STARTUP_TEST */
1592 static void add_tracer_options(struct trace_array *tr, struct tracer *t);
1594 static void __init apply_trace_boot_options(void);
1597 * register_tracer - register a tracer with the ftrace system.
1598 * @type - the plugin for the tracer
1600 * Register a new plugin tracer.
1602 int __init register_tracer(struct tracer *type)
1608 pr_info("Tracer must have a name\n");
1612 if (strlen(type->name) >= MAX_TRACER_SIZE) {
1613 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
1617 mutex_lock(&trace_types_lock);
1619 tracing_selftest_running = true;
1621 for (t = trace_types; t; t = t->next) {
1622 if (strcmp(type->name, t->name) == 0) {
1624 pr_info("Tracer %s already registered\n",
1631 if (!type->set_flag)
1632 type->set_flag = &dummy_set_flag;
1634 /*allocate a dummy tracer_flags*/
1635 type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
1640 type->flags->val = 0;
1641 type->flags->opts = dummy_tracer_opt;
1643 if (!type->flags->opts)
1644 type->flags->opts = dummy_tracer_opt;
1646 /* store the tracer for __set_tracer_option */
1647 type->flags->trace = type;
1649 ret = run_tracer_selftest(type);
1653 type->next = trace_types;
1655 add_tracer_options(&global_trace, type);
1658 tracing_selftest_running = false;
1659 mutex_unlock(&trace_types_lock);
1661 if (ret || !default_bootup_tracer)
1664 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
1667 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
1668 /* Do we want this tracer to start on bootup? */
1669 tracing_set_tracer(&global_trace, type->name);
1670 default_bootup_tracer = NULL;
1672 apply_trace_boot_options();
1674 /* disable other selftests, since this will break it. */
1675 tracing_selftest_disabled = true;
1676 #ifdef CONFIG_FTRACE_STARTUP_TEST
1677 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
1685 void tracing_reset(struct trace_buffer *buf, int cpu)
1687 struct ring_buffer *buffer = buf->buffer;
1692 ring_buffer_record_disable(buffer);
1694 /* Make sure all commits have finished */
1695 synchronize_sched();
1696 ring_buffer_reset_cpu(buffer, cpu);
1698 ring_buffer_record_enable(buffer);
1701 void tracing_reset_online_cpus(struct trace_buffer *buf)
1703 struct ring_buffer *buffer = buf->buffer;
1709 ring_buffer_record_disable(buffer);
1711 /* Make sure all commits have finished */
1712 synchronize_sched();
1714 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
1716 for_each_online_cpu(cpu)
1717 ring_buffer_reset_cpu(buffer, cpu);
1719 ring_buffer_record_enable(buffer);
1722 /* Must have trace_types_lock held */
1723 void tracing_reset_all_online_cpus(void)
1725 struct trace_array *tr;
1727 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1728 if (!tr->clear_trace)
1730 tr->clear_trace = false;
1731 tracing_reset_online_cpus(&tr->trace_buffer);
1732 #ifdef CONFIG_TRACER_MAX_TRACE
1733 tracing_reset_online_cpus(&tr->max_buffer);
1739 * The tgid_map array maps from pid to tgid; i.e. the value stored at index i
1740 * is the tgid last observed corresponding to pid=i.
1742 static int *tgid_map;
1744 /* The maximum valid index into tgid_map. */
1745 static size_t tgid_map_max;
1747 #define SAVED_CMDLINES_DEFAULT 128
1748 #define NO_CMDLINE_MAP UINT_MAX
1749 static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1750 struct saved_cmdlines_buffer {
1751 unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
1752 unsigned *map_cmdline_to_pid;
1753 unsigned cmdline_num;
1755 char *saved_cmdlines;
1757 static struct saved_cmdlines_buffer *savedcmd;
1759 static inline char *get_saved_cmdlines(int idx)
1761 return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
1764 static inline void set_cmdline(int idx, const char *cmdline)
1766 memcpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
1769 static int allocate_cmdlines_buffer(unsigned int val,
1770 struct saved_cmdlines_buffer *s)
1772 s->map_cmdline_to_pid = kmalloc_array(val,
1773 sizeof(*s->map_cmdline_to_pid),
1775 if (!s->map_cmdline_to_pid)
1778 s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL);
1779 if (!s->saved_cmdlines) {
1780 kfree(s->map_cmdline_to_pid);
1785 s->cmdline_num = val;
1786 memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
1787 sizeof(s->map_pid_to_cmdline));
1788 memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
1789 val * sizeof(*s->map_cmdline_to_pid));
1794 static int trace_create_savedcmd(void)
1798 savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
1802 ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
1812 int is_tracing_stopped(void)
1814 return global_trace.stop_count;
1818 * tracing_start - quick start of the tracer
1820 * If tracing is enabled but was stopped by tracing_stop,
1821 * this will start the tracer back up.
1823 void tracing_start(void)
1825 struct ring_buffer *buffer;
1826 unsigned long flags;
1828 if (tracing_disabled)
1831 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1832 if (--global_trace.stop_count) {
1833 if (global_trace.stop_count < 0) {
1834 /* Someone screwed up their debugging */
1836 global_trace.stop_count = 0;
1841 /* Prevent the buffers from switching */
1842 arch_spin_lock(&global_trace.max_lock);
1844 buffer = global_trace.trace_buffer.buffer;
1846 ring_buffer_record_enable(buffer);
1848 #ifdef CONFIG_TRACER_MAX_TRACE
1849 buffer = global_trace.max_buffer.buffer;
1851 ring_buffer_record_enable(buffer);
1854 arch_spin_unlock(&global_trace.max_lock);
1857 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1860 static void tracing_start_tr(struct trace_array *tr)
1862 struct ring_buffer *buffer;
1863 unsigned long flags;
1865 if (tracing_disabled)
1868 /* If global, we need to also start the max tracer */
1869 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1870 return tracing_start();
1872 raw_spin_lock_irqsave(&tr->start_lock, flags);
1874 if (--tr->stop_count) {
1875 if (tr->stop_count < 0) {
1876 /* Someone screwed up their debugging */
1883 buffer = tr->trace_buffer.buffer;
1885 ring_buffer_record_enable(buffer);
1888 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1892 * tracing_stop - quick stop of the tracer
1894 * Light weight way to stop tracing. Use in conjunction with
1897 void tracing_stop(void)
1899 struct ring_buffer *buffer;
1900 unsigned long flags;
1902 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1903 if (global_trace.stop_count++)
1906 /* Prevent the buffers from switching */
1907 arch_spin_lock(&global_trace.max_lock);
1909 buffer = global_trace.trace_buffer.buffer;
1911 ring_buffer_record_disable(buffer);
1913 #ifdef CONFIG_TRACER_MAX_TRACE
1914 buffer = global_trace.max_buffer.buffer;
1916 ring_buffer_record_disable(buffer);
1919 arch_spin_unlock(&global_trace.max_lock);
1922 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1925 static void tracing_stop_tr(struct trace_array *tr)
1927 struct ring_buffer *buffer;
1928 unsigned long flags;
1930 /* If global, we need to also stop the max tracer */
1931 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1932 return tracing_stop();
1934 raw_spin_lock_irqsave(&tr->start_lock, flags);
1935 if (tr->stop_count++)
1938 buffer = tr->trace_buffer.buffer;
1940 ring_buffer_record_disable(buffer);
1943 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1946 static int trace_save_cmdline(struct task_struct *tsk)
1950 /* treat recording of idle task as a success */
1954 tpid = tsk->pid & (PID_MAX_DEFAULT - 1);
1957 * It's not the end of the world if we don't get
1958 * the lock, but we also don't want to spin
1959 * nor do we want to disable interrupts,
1960 * so if we miss here, then better luck next time.
1962 if (!arch_spin_trylock(&trace_cmdline_lock))
1965 idx = savedcmd->map_pid_to_cmdline[tpid];
1966 if (idx == NO_CMDLINE_MAP) {
1967 idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
1969 savedcmd->map_pid_to_cmdline[tpid] = idx;
1970 savedcmd->cmdline_idx = idx;
1973 savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
1974 set_cmdline(idx, tsk->comm);
1976 arch_spin_unlock(&trace_cmdline_lock);
1981 static void __trace_find_cmdline(int pid, char comm[])
1987 strcpy(comm, "<idle>");
1991 if (WARN_ON_ONCE(pid < 0)) {
1992 strcpy(comm, "<XXX>");
1996 tpid = pid & (PID_MAX_DEFAULT - 1);
1997 map = savedcmd->map_pid_to_cmdline[tpid];
1998 if (map != NO_CMDLINE_MAP) {
1999 tpid = savedcmd->map_cmdline_to_pid[map];
2001 strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
2005 strcpy(comm, "<...>");
2008 void trace_find_cmdline(int pid, char comm[])
2011 arch_spin_lock(&trace_cmdline_lock);
2013 __trace_find_cmdline(pid, comm);
2015 arch_spin_unlock(&trace_cmdline_lock);
2019 static int *trace_find_tgid_ptr(int pid)
2022 * Pairs with the smp_store_release in set_tracer_flag() to ensure that
2023 * if we observe a non-NULL tgid_map then we also observe the correct
2026 int *map = smp_load_acquire(&tgid_map);
2028 if (unlikely(!map || pid > tgid_map_max))
2034 int trace_find_tgid(int pid)
2036 int *ptr = trace_find_tgid_ptr(pid);
2038 return ptr ? *ptr : 0;
2041 static int trace_save_tgid(struct task_struct *tsk)
2045 /* treat recording of idle task as a success */
2049 ptr = trace_find_tgid_ptr(tsk->pid);
2057 static bool tracing_record_taskinfo_skip(int flags)
2059 if (unlikely(!(flags & (TRACE_RECORD_CMDLINE | TRACE_RECORD_TGID))))
2061 if (!__this_cpu_read(trace_taskinfo_save))
2067 * tracing_record_taskinfo - record the task info of a task
2069 * @task - task to record
2070 * @flags - TRACE_RECORD_CMDLINE for recording comm
2071 * - TRACE_RECORD_TGID for recording tgid
2073 void tracing_record_taskinfo(struct task_struct *task, int flags)
2077 if (tracing_record_taskinfo_skip(flags))
2081 * Record as much task information as possible. If some fail, continue
2082 * to try to record the others.
2084 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task);
2085 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task);
2087 /* If recording any information failed, retry again soon. */
2091 __this_cpu_write(trace_taskinfo_save, false);
2095 * tracing_record_taskinfo_sched_switch - record task info for sched_switch
2097 * @prev - previous task during sched_switch
2098 * @next - next task during sched_switch
2099 * @flags - TRACE_RECORD_CMDLINE for recording comm
2100 * TRACE_RECORD_TGID for recording tgid
2102 void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
2103 struct task_struct *next, int flags)
2107 if (tracing_record_taskinfo_skip(flags))
2111 * Record as much task information as possible. If some fail, continue
2112 * to try to record the others.
2114 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev);
2115 done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next);
2116 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev);
2117 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next);
2119 /* If recording any information failed, retry again soon. */
2123 __this_cpu_write(trace_taskinfo_save, false);
2126 /* Helpers to record a specific task information */
2127 void tracing_record_cmdline(struct task_struct *task)
2129 tracing_record_taskinfo(task, TRACE_RECORD_CMDLINE);
2132 void tracing_record_tgid(struct task_struct *task)
2134 tracing_record_taskinfo(task, TRACE_RECORD_TGID);
2138 * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
2139 * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
2140 * simplifies those functions and keeps them in sync.
2142 enum print_line_t trace_handle_return(struct trace_seq *s)
2144 return trace_seq_has_overflowed(s) ?
2145 TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
2147 EXPORT_SYMBOL_GPL(trace_handle_return);
2150 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
2153 struct task_struct *tsk = current;
2155 entry->preempt_count = pc & 0xff;
2156 entry->pid = (tsk) ? tsk->pid : 0;
2158 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
2159 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
2161 TRACE_FLAG_IRQS_NOSUPPORT |
2163 ((pc & NMI_MASK ) ? TRACE_FLAG_NMI : 0) |
2164 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
2165 ((pc & SOFTIRQ_OFFSET) ? TRACE_FLAG_SOFTIRQ : 0) |
2166 (tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
2167 (test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
2169 EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
2171 struct ring_buffer_event *
2172 trace_buffer_lock_reserve(struct ring_buffer *buffer,
2175 unsigned long flags, int pc)
2177 return __trace_buffer_lock_reserve(buffer, type, len, flags, pc);
2180 DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
2181 DEFINE_PER_CPU(int, trace_buffered_event_cnt);
2182 static int trace_buffered_event_ref;
2185 * trace_buffered_event_enable - enable buffering events
2187 * When events are being filtered, it is quicker to use a temporary
2188 * buffer to write the event data into if there's a likely chance
2189 * that it will not be committed. The discard of the ring buffer
2190 * is not as fast as committing, and is much slower than copying
2193 * When an event is to be filtered, allocate per cpu buffers to
2194 * write the event data into, and if the event is filtered and discarded
2195 * it is simply dropped, otherwise, the entire data is to be committed
2198 void trace_buffered_event_enable(void)
2200 struct ring_buffer_event *event;
2204 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2206 if (trace_buffered_event_ref++)
2209 for_each_tracing_cpu(cpu) {
2210 page = alloc_pages_node(cpu_to_node(cpu),
2211 GFP_KERNEL | __GFP_NORETRY, 0);
2215 event = page_address(page);
2216 memset(event, 0, sizeof(*event));
2218 per_cpu(trace_buffered_event, cpu) = event;
2221 if (cpu == smp_processor_id() &&
2222 this_cpu_read(trace_buffered_event) !=
2223 per_cpu(trace_buffered_event, cpu))
2230 trace_buffered_event_disable();
2233 static void enable_trace_buffered_event(void *data)
2235 /* Probably not needed, but do it anyway */
2237 this_cpu_dec(trace_buffered_event_cnt);
2240 static void disable_trace_buffered_event(void *data)
2242 this_cpu_inc(trace_buffered_event_cnt);
2246 * trace_buffered_event_disable - disable buffering events
2248 * When a filter is removed, it is faster to not use the buffered
2249 * events, and to commit directly into the ring buffer. Free up
2250 * the temp buffers when there are no more users. This requires
2251 * special synchronization with current events.
2253 void trace_buffered_event_disable(void)
2257 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2259 if (WARN_ON_ONCE(!trace_buffered_event_ref))
2262 if (--trace_buffered_event_ref)
2266 /* For each CPU, set the buffer as used. */
2267 smp_call_function_many(tracing_buffer_mask,
2268 disable_trace_buffered_event, NULL, 1);
2271 /* Wait for all current users to finish */
2272 synchronize_sched();
2274 for_each_tracing_cpu(cpu) {
2275 free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
2276 per_cpu(trace_buffered_event, cpu) = NULL;
2279 * Make sure trace_buffered_event is NULL before clearing
2280 * trace_buffered_event_cnt.
2285 /* Do the work on each cpu */
2286 smp_call_function_many(tracing_buffer_mask,
2287 enable_trace_buffered_event, NULL, 1);
2291 static struct ring_buffer *temp_buffer;
2293 struct ring_buffer_event *
2294 trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
2295 struct trace_event_file *trace_file,
2296 int type, unsigned long len,
2297 unsigned long flags, int pc)
2299 struct ring_buffer_event *entry;
2302 *current_rb = trace_file->tr->trace_buffer.buffer;
2304 if (!ring_buffer_time_stamp_abs(*current_rb) && (trace_file->flags &
2305 (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
2306 (entry = this_cpu_read(trace_buffered_event))) {
2307 /* Try to use the per cpu buffer first */
2308 val = this_cpu_inc_return(trace_buffered_event_cnt);
2309 if ((len < (PAGE_SIZE - sizeof(*entry) - sizeof(entry->array[0]))) && val == 1) {
2310 trace_event_setup(entry, type, flags, pc);
2311 entry->array[0] = len;
2314 this_cpu_dec(trace_buffered_event_cnt);
2317 entry = __trace_buffer_lock_reserve(*current_rb,
2318 type, len, flags, pc);
2320 * If tracing is off, but we have triggers enabled
2321 * we still need to look at the event data. Use the temp_buffer
2322 * to store the trace event for the tigger to use. It's recusive
2323 * safe and will not be recorded anywhere.
2325 if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
2326 *current_rb = temp_buffer;
2327 entry = __trace_buffer_lock_reserve(*current_rb,
2328 type, len, flags, pc);
2332 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
2334 static DEFINE_SPINLOCK(tracepoint_iter_lock);
2335 static DEFINE_MUTEX(tracepoint_printk_mutex);
2337 static void output_printk(struct trace_event_buffer *fbuffer)
2339 struct trace_event_call *event_call;
2340 struct trace_event *event;
2341 unsigned long flags;
2342 struct trace_iterator *iter = tracepoint_print_iter;
2344 /* We should never get here if iter is NULL */
2345 if (WARN_ON_ONCE(!iter))
2348 event_call = fbuffer->trace_file->event_call;
2349 if (!event_call || !event_call->event.funcs ||
2350 !event_call->event.funcs->trace)
2353 event = &fbuffer->trace_file->event_call->event;
2355 spin_lock_irqsave(&tracepoint_iter_lock, flags);
2356 trace_seq_init(&iter->seq);
2357 iter->ent = fbuffer->entry;
2358 event_call->event.funcs->trace(iter, 0, event);
2359 trace_seq_putc(&iter->seq, 0);
2360 printk("%s", iter->seq.buffer);
2362 spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
2365 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
2366 void __user *buffer, size_t *lenp,
2369 int save_tracepoint_printk;
2372 mutex_lock(&tracepoint_printk_mutex);
2373 save_tracepoint_printk = tracepoint_printk;
2375 ret = proc_dointvec(table, write, buffer, lenp, ppos);
2378 * This will force exiting early, as tracepoint_printk
2379 * is always zero when tracepoint_printk_iter is not allocated
2381 if (!tracepoint_print_iter)
2382 tracepoint_printk = 0;
2384 if (save_tracepoint_printk == tracepoint_printk)
2387 if (tracepoint_printk)
2388 static_key_enable(&tracepoint_printk_key.key);
2390 static_key_disable(&tracepoint_printk_key.key);
2393 mutex_unlock(&tracepoint_printk_mutex);
2398 void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
2400 if (static_key_false(&tracepoint_printk_key.key))
2401 output_printk(fbuffer);
2403 event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer,
2404 fbuffer->event, fbuffer->entry,
2405 fbuffer->flags, fbuffer->pc);
2407 EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
2412 * trace_buffer_unlock_commit_regs()
2413 * trace_event_buffer_commit()
2414 * trace_event_raw_event_xxx()
2416 # define STACK_SKIP 3
2418 void trace_buffer_unlock_commit_regs(struct trace_array *tr,
2419 struct ring_buffer *buffer,
2420 struct ring_buffer_event *event,
2421 unsigned long flags, int pc,
2422 struct pt_regs *regs)
2424 __buffer_unlock_commit(buffer, event);
2427 * If regs is not set, then skip the necessary functions.
2428 * Note, we can still get here via blktrace, wakeup tracer
2429 * and mmiotrace, but that's ok if they lose a function or
2430 * two. They are not that meaningful.
2432 ftrace_trace_stack(tr, buffer, flags, regs ? 0 : STACK_SKIP, pc, regs);
2433 ftrace_trace_userstack(tr, buffer, flags, pc);
2437 * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
2440 trace_buffer_unlock_commit_nostack(struct ring_buffer *buffer,
2441 struct ring_buffer_event *event)
2443 __buffer_unlock_commit(buffer, event);
2447 trace_process_export(struct trace_export *export,
2448 struct ring_buffer_event *event)
2450 struct trace_entry *entry;
2451 unsigned int size = 0;
2453 entry = ring_buffer_event_data(event);
2454 size = ring_buffer_event_length(event);
2455 export->write(export, entry, size);
2458 static DEFINE_MUTEX(ftrace_export_lock);
2460 static struct trace_export __rcu *ftrace_exports_list __read_mostly;
2462 static DEFINE_STATIC_KEY_FALSE(ftrace_exports_enabled);
2464 static inline void ftrace_exports_enable(void)
2466 static_branch_enable(&ftrace_exports_enabled);
2469 static inline void ftrace_exports_disable(void)
2471 static_branch_disable(&ftrace_exports_enabled);
2474 void ftrace_exports(struct ring_buffer_event *event)
2476 struct trace_export *export;
2478 preempt_disable_notrace();
2480 export = rcu_dereference_raw_notrace(ftrace_exports_list);
2482 trace_process_export(export, event);
2483 export = rcu_dereference_raw_notrace(export->next);
2486 preempt_enable_notrace();
2490 add_trace_export(struct trace_export **list, struct trace_export *export)
2492 rcu_assign_pointer(export->next, *list);
2494 * We are entering export into the list but another
2495 * CPU might be walking that list. We need to make sure
2496 * the export->next pointer is valid before another CPU sees
2497 * the export pointer included into the list.
2499 rcu_assign_pointer(*list, export);
2503 rm_trace_export(struct trace_export **list, struct trace_export *export)
2505 struct trace_export **p;
2507 for (p = list; *p != NULL; p = &(*p)->next)
2514 rcu_assign_pointer(*p, (*p)->next);
2520 add_ftrace_export(struct trace_export **list, struct trace_export *export)
2523 ftrace_exports_enable();
2525 add_trace_export(list, export);
2529 rm_ftrace_export(struct trace_export **list, struct trace_export *export)
2533 ret = rm_trace_export(list, export);
2535 ftrace_exports_disable();
2540 int register_ftrace_export(struct trace_export *export)
2542 if (WARN_ON_ONCE(!export->write))
2545 mutex_lock(&ftrace_export_lock);
2547 add_ftrace_export(&ftrace_exports_list, export);
2549 mutex_unlock(&ftrace_export_lock);
2553 EXPORT_SYMBOL_GPL(register_ftrace_export);
2555 int unregister_ftrace_export(struct trace_export *export)
2559 mutex_lock(&ftrace_export_lock);
2561 ret = rm_ftrace_export(&ftrace_exports_list, export);
2563 mutex_unlock(&ftrace_export_lock);
2567 EXPORT_SYMBOL_GPL(unregister_ftrace_export);
2570 trace_function(struct trace_array *tr,
2571 unsigned long ip, unsigned long parent_ip, unsigned long flags,
2574 struct trace_event_call *call = &event_function;
2575 struct ring_buffer *buffer = tr->trace_buffer.buffer;
2576 struct ring_buffer_event *event;
2577 struct ftrace_entry *entry;
2579 event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
2583 entry = ring_buffer_event_data(event);
2585 entry->parent_ip = parent_ip;
2587 if (!call_filter_check_discard(call, entry, buffer, event)) {
2588 if (static_branch_unlikely(&ftrace_exports_enabled))
2589 ftrace_exports(event);
2590 __buffer_unlock_commit(buffer, event);
2594 #ifdef CONFIG_STACKTRACE
2596 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
2597 struct ftrace_stack {
2598 unsigned long calls[FTRACE_STACK_MAX_ENTRIES];
2601 static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
2602 static DEFINE_PER_CPU(int, ftrace_stack_reserve);
2604 static void __ftrace_trace_stack(struct ring_buffer *buffer,
2605 unsigned long flags,
2606 int skip, int pc, struct pt_regs *regs)
2608 struct trace_event_call *call = &event_kernel_stack;
2609 struct ring_buffer_event *event;
2610 struct stack_entry *entry;
2611 struct stack_trace trace;
2613 int size = FTRACE_STACK_ENTRIES;
2615 trace.nr_entries = 0;
2619 * Add one, for this function and the call to save_stack_trace()
2620 * If regs is set, then these functions will not be in the way.
2622 #ifndef CONFIG_UNWINDER_ORC
2628 * Since events can happen in NMIs there's no safe way to
2629 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
2630 * or NMI comes in, it will just have to use the default
2631 * FTRACE_STACK_SIZE.
2633 preempt_disable_notrace();
2635 use_stack = __this_cpu_inc_return(ftrace_stack_reserve);
2637 * We don't need any atomic variables, just a barrier.
2638 * If an interrupt comes in, we don't care, because it would
2639 * have exited and put the counter back to what we want.
2640 * We just need a barrier to keep gcc from moving things
2644 if (use_stack == 1) {
2645 trace.entries = this_cpu_ptr(ftrace_stack.calls);
2646 trace.max_entries = FTRACE_STACK_MAX_ENTRIES;
2649 save_stack_trace_regs(regs, &trace);
2651 save_stack_trace(&trace);
2653 if (trace.nr_entries > size)
2654 size = trace.nr_entries;
2656 /* From now on, use_stack is a boolean */
2659 size *= sizeof(unsigned long);
2661 event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
2662 (sizeof(*entry) - sizeof(entry->caller)) + size,
2666 entry = ring_buffer_event_data(event);
2668 memset(&entry->caller, 0, size);
2671 memcpy(&entry->caller, trace.entries,
2672 trace.nr_entries * sizeof(unsigned long));
2674 trace.max_entries = FTRACE_STACK_ENTRIES;
2675 trace.entries = entry->caller;
2677 save_stack_trace_regs(regs, &trace);
2679 save_stack_trace(&trace);
2682 entry->size = trace.nr_entries;
2684 if (!call_filter_check_discard(call, entry, buffer, event))
2685 __buffer_unlock_commit(buffer, event);
2688 /* Again, don't let gcc optimize things here */
2690 __this_cpu_dec(ftrace_stack_reserve);
2691 preempt_enable_notrace();
2695 static inline void ftrace_trace_stack(struct trace_array *tr,
2696 struct ring_buffer *buffer,
2697 unsigned long flags,
2698 int skip, int pc, struct pt_regs *regs)
2700 if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
2703 __ftrace_trace_stack(buffer, flags, skip, pc, regs);
2706 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
2709 struct ring_buffer *buffer = tr->trace_buffer.buffer;
2711 if (rcu_is_watching()) {
2712 __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
2717 * When an NMI triggers, RCU is enabled via rcu_nmi_enter(),
2718 * but if the above rcu_is_watching() failed, then the NMI
2719 * triggered someplace critical, and rcu_irq_enter() should
2720 * not be called from NMI.
2722 if (unlikely(in_nmi()))
2725 rcu_irq_enter_irqson();
2726 __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
2727 rcu_irq_exit_irqson();
2731 * trace_dump_stack - record a stack back trace in the trace buffer
2732 * @skip: Number of functions to skip (helper handlers)
2734 void trace_dump_stack(int skip)
2736 unsigned long flags;
2738 if (tracing_disabled || tracing_selftest_running)
2741 local_save_flags(flags);
2743 #ifndef CONFIG_UNWINDER_ORC
2744 /* Skip 1 to skip this function. */
2747 __ftrace_trace_stack(global_trace.trace_buffer.buffer,
2748 flags, skip, preempt_count(), NULL);
2751 static DEFINE_PER_CPU(int, user_stack_count);
2754 ftrace_trace_userstack(struct trace_array *tr,
2755 struct ring_buffer *buffer, unsigned long flags, int pc)
2757 struct trace_event_call *call = &event_user_stack;
2758 struct ring_buffer_event *event;
2759 struct userstack_entry *entry;
2760 struct stack_trace trace;
2762 if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE))
2766 * NMIs can not handle page faults, even with fix ups.
2767 * The save user stack can (and often does) fault.
2769 if (unlikely(in_nmi()))
2773 * prevent recursion, since the user stack tracing may
2774 * trigger other kernel events.
2777 if (__this_cpu_read(user_stack_count))
2780 __this_cpu_inc(user_stack_count);
2782 event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
2783 sizeof(*entry), flags, pc);
2785 goto out_drop_count;
2786 entry = ring_buffer_event_data(event);
2788 entry->tgid = current->tgid;
2789 memset(&entry->caller, 0, sizeof(entry->caller));
2791 trace.nr_entries = 0;
2792 trace.max_entries = FTRACE_STACK_ENTRIES;
2794 trace.entries = entry->caller;
2796 save_stack_trace_user(&trace);
2797 if (!call_filter_check_discard(call, entry, buffer, event))
2798 __buffer_unlock_commit(buffer, event);
2801 __this_cpu_dec(user_stack_count);
2807 static void __trace_userstack(struct trace_array *tr, unsigned long flags)
2809 ftrace_trace_userstack(tr, flags, preempt_count());
2813 #endif /* CONFIG_STACKTRACE */
2815 /* created for use with alloc_percpu */
2816 struct trace_buffer_struct {
2818 char buffer[4][TRACE_BUF_SIZE];
2821 static struct trace_buffer_struct __percpu *trace_percpu_buffer;
2824 * Thise allows for lockless recording. If we're nested too deeply, then
2825 * this returns NULL.
2827 static char *get_trace_buf(void)
2829 struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
2831 if (!trace_percpu_buffer || buffer->nesting >= 4)
2836 /* Interrupts must see nesting incremented before we use the buffer */
2838 return &buffer->buffer[buffer->nesting - 1][0];
2841 static void put_trace_buf(void)
2843 /* Don't let the decrement of nesting leak before this */
2845 this_cpu_dec(trace_percpu_buffer->nesting);
2848 static int alloc_percpu_trace_buffer(void)
2850 struct trace_buffer_struct __percpu *buffers;
2852 buffers = alloc_percpu(struct trace_buffer_struct);
2853 if (WARN(!buffers, "Could not allocate percpu trace_printk buffer"))
2856 trace_percpu_buffer = buffers;
2860 static int buffers_allocated;
2862 void trace_printk_init_buffers(void)
2864 if (buffers_allocated)
2867 if (alloc_percpu_trace_buffer())
2870 /* trace_printk() is for debug use only. Don't use it in production. */
2873 pr_warn("**********************************************************\n");
2874 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
2876 pr_warn("** trace_printk() being used. Allocating extra memory. **\n");
2878 pr_warn("** This means that this is a DEBUG kernel and it is **\n");
2879 pr_warn("** unsafe for production use. **\n");
2881 pr_warn("** If you see this message and you are not debugging **\n");
2882 pr_warn("** the kernel, report this immediately to your vendor! **\n");
2884 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
2885 pr_warn("**********************************************************\n");
2887 /* Expand the buffers to set size */
2888 tracing_update_buffers();
2890 buffers_allocated = 1;
2893 * trace_printk_init_buffers() can be called by modules.
2894 * If that happens, then we need to start cmdline recording
2895 * directly here. If the global_trace.buffer is already
2896 * allocated here, then this was called by module code.
2898 if (global_trace.trace_buffer.buffer)
2899 tracing_start_cmdline_record();
2902 void trace_printk_start_comm(void)
2904 /* Start tracing comms if trace printk is set */
2905 if (!buffers_allocated)
2907 tracing_start_cmdline_record();
2910 static void trace_printk_start_stop_comm(int enabled)
2912 if (!buffers_allocated)
2916 tracing_start_cmdline_record();
2918 tracing_stop_cmdline_record();
2922 * trace_vbprintk - write binary msg to tracing buffer
2925 int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
2927 struct trace_event_call *call = &event_bprint;
2928 struct ring_buffer_event *event;
2929 struct ring_buffer *buffer;
2930 struct trace_array *tr = &global_trace;
2931 struct bprint_entry *entry;
2932 unsigned long flags;
2934 int len = 0, size, pc;
2936 if (unlikely(tracing_selftest_running || tracing_disabled))
2939 /* Don't pollute graph traces with trace_vprintk internals */
2940 pause_graph_tracing();
2942 pc = preempt_count();
2943 preempt_disable_notrace();
2945 tbuffer = get_trace_buf();
2951 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
2953 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
2956 local_save_flags(flags);
2957 size = sizeof(*entry) + sizeof(u32) * len;
2958 buffer = tr->trace_buffer.buffer;
2959 event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
2963 entry = ring_buffer_event_data(event);
2967 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
2968 if (!call_filter_check_discard(call, entry, buffer, event)) {
2969 __buffer_unlock_commit(buffer, event);
2970 ftrace_trace_stack(tr, buffer, flags, 6, pc, NULL);
2977 preempt_enable_notrace();
2978 unpause_graph_tracing();
2982 EXPORT_SYMBOL_GPL(trace_vbprintk);
2986 __trace_array_vprintk(struct ring_buffer *buffer,
2987 unsigned long ip, const char *fmt, va_list args)
2989 struct trace_event_call *call = &event_print;
2990 struct ring_buffer_event *event;
2991 int len = 0, size, pc;
2992 struct print_entry *entry;
2993 unsigned long flags;
2996 if (tracing_disabled || tracing_selftest_running)
2999 /* Don't pollute graph traces with trace_vprintk internals */
3000 pause_graph_tracing();
3002 pc = preempt_count();
3003 preempt_disable_notrace();
3006 tbuffer = get_trace_buf();
3012 len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
3014 local_save_flags(flags);
3015 size = sizeof(*entry) + len + 1;
3016 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
3020 entry = ring_buffer_event_data(event);
3023 memcpy(&entry->buf, tbuffer, len + 1);
3024 if (!call_filter_check_discard(call, entry, buffer, event)) {
3025 __buffer_unlock_commit(buffer, event);
3026 ftrace_trace_stack(&global_trace, buffer, flags, 6, pc, NULL);
3033 preempt_enable_notrace();
3034 unpause_graph_tracing();
3040 int trace_array_vprintk(struct trace_array *tr,
3041 unsigned long ip, const char *fmt, va_list args)
3043 return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
3047 int trace_array_printk(struct trace_array *tr,
3048 unsigned long ip, const char *fmt, ...)
3053 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
3060 ret = trace_array_vprintk(tr, ip, fmt, ap);
3066 int trace_array_printk_buf(struct ring_buffer *buffer,
3067 unsigned long ip, const char *fmt, ...)
3072 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
3076 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
3082 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
3084 return trace_array_vprintk(&global_trace, ip, fmt, args);
3086 EXPORT_SYMBOL_GPL(trace_vprintk);
3088 static void trace_iterator_increment(struct trace_iterator *iter)
3090 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
3094 ring_buffer_read(buf_iter, NULL);
3097 static struct trace_entry *
3098 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
3099 unsigned long *lost_events)
3101 struct ring_buffer_event *event;
3102 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
3105 event = ring_buffer_iter_peek(buf_iter, ts);
3107 event = ring_buffer_peek(iter->trace_buffer->buffer, cpu, ts,
3111 iter->ent_size = ring_buffer_event_length(event);
3112 return ring_buffer_event_data(event);
3118 static struct trace_entry *
3119 __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
3120 unsigned long *missing_events, u64 *ent_ts)
3122 struct ring_buffer *buffer = iter->trace_buffer->buffer;
3123 struct trace_entry *ent, *next = NULL;
3124 unsigned long lost_events = 0, next_lost = 0;
3125 int cpu_file = iter->cpu_file;
3126 u64 next_ts = 0, ts;
3132 * If we are in a per_cpu trace file, don't bother by iterating over
3133 * all cpu and peek directly.
3135 if (cpu_file > RING_BUFFER_ALL_CPUS) {
3136 if (ring_buffer_empty_cpu(buffer, cpu_file))
3138 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
3140 *ent_cpu = cpu_file;
3145 for_each_tracing_cpu(cpu) {
3147 if (ring_buffer_empty_cpu(buffer, cpu))
3150 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
3153 * Pick the entry with the smallest timestamp:
3155 if (ent && (!next || ts < next_ts)) {
3159 next_lost = lost_events;
3160 next_size = iter->ent_size;
3164 iter->ent_size = next_size;
3167 *ent_cpu = next_cpu;
3173 *missing_events = next_lost;
3178 /* Find the next real entry, without updating the iterator itself */
3179 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
3180 int *ent_cpu, u64 *ent_ts)
3182 return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
3185 /* Find the next real entry, and increment the iterator to the next entry */
3186 void *trace_find_next_entry_inc(struct trace_iterator *iter)
3188 iter->ent = __find_next_entry(iter, &iter->cpu,
3189 &iter->lost_events, &iter->ts);
3192 trace_iterator_increment(iter);
3194 return iter->ent ? iter : NULL;
3197 static void trace_consume(struct trace_iterator *iter)
3199 ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu, &iter->ts,
3200 &iter->lost_events);
3203 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
3205 struct trace_iterator *iter = m->private;
3209 WARN_ON_ONCE(iter->leftover);
3213 /* can't go backwards */
3218 ent = trace_find_next_entry_inc(iter);
3222 while (ent && iter->idx < i)
3223 ent = trace_find_next_entry_inc(iter);
3230 void tracing_iter_reset(struct trace_iterator *iter, int cpu)
3232 struct ring_buffer_event *event;
3233 struct ring_buffer_iter *buf_iter;
3234 unsigned long entries = 0;
3237 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = 0;
3239 buf_iter = trace_buffer_iter(iter, cpu);
3243 ring_buffer_iter_reset(buf_iter);
3246 * We could have the case with the max latency tracers
3247 * that a reset never took place on a cpu. This is evident
3248 * by the timestamp being before the start of the buffer.
3250 while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
3251 if (ts >= iter->trace_buffer->time_start)
3254 ring_buffer_read(buf_iter, NULL);
3257 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = entries;
3261 * The current tracer is copied to avoid a global locking
3264 static void *s_start(struct seq_file *m, loff_t *pos)
3266 struct trace_iterator *iter = m->private;
3267 struct trace_array *tr = iter->tr;
3268 int cpu_file = iter->cpu_file;
3274 * copy the tracer to avoid using a global lock all around.
3275 * iter->trace is a copy of current_trace, the pointer to the
3276 * name may be used instead of a strcmp(), as iter->trace->name
3277 * will point to the same string as current_trace->name.
3279 mutex_lock(&trace_types_lock);
3280 if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
3281 *iter->trace = *tr->current_trace;
3282 mutex_unlock(&trace_types_lock);
3284 #ifdef CONFIG_TRACER_MAX_TRACE
3285 if (iter->snapshot && iter->trace->use_max_tr)
3286 return ERR_PTR(-EBUSY);
3289 if (*pos != iter->pos) {
3294 if (cpu_file == RING_BUFFER_ALL_CPUS) {
3295 for_each_tracing_cpu(cpu)
3296 tracing_iter_reset(iter, cpu);
3298 tracing_iter_reset(iter, cpu_file);
3301 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
3306 * If we overflowed the seq_file before, then we want
3307 * to just reuse the trace_seq buffer again.
3313 p = s_next(m, p, &l);
3317 trace_event_read_lock();
3318 trace_access_lock(cpu_file);
3322 static void s_stop(struct seq_file *m, void *p)
3324 struct trace_iterator *iter = m->private;
3326 #ifdef CONFIG_TRACER_MAX_TRACE
3327 if (iter->snapshot && iter->trace->use_max_tr)
3331 trace_access_unlock(iter->cpu_file);
3332 trace_event_read_unlock();
3336 get_total_entries(struct trace_buffer *buf,
3337 unsigned long *total, unsigned long *entries)
3339 unsigned long count;
3345 for_each_tracing_cpu(cpu) {
3346 count = ring_buffer_entries_cpu(buf->buffer, cpu);
3348 * If this buffer has skipped entries, then we hold all
3349 * entries for the trace and we need to ignore the
3350 * ones before the time stamp.
3352 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
3353 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
3354 /* total is the same as the entries */
3358 ring_buffer_overrun_cpu(buf->buffer, cpu);
3363 static void print_lat_help_header(struct seq_file *m)
3365 seq_puts(m, "# _------=> CPU# \n"
3366 "# / _-----=> irqs-off \n"
3367 "# | / _----=> need-resched \n"
3368 "# || / _---=> hardirq/softirq \n"
3369 "# ||| / _--=> preempt-depth \n"
3371 "# cmd pid ||||| time | caller \n"
3372 "# \\ / ||||| \\ | / \n");
3375 static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
3377 unsigned long total;
3378 unsigned long entries;
3380 get_total_entries(buf, &total, &entries);
3381 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
3382 entries, total, num_online_cpus());
3386 static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m,
3389 bool tgid = flags & TRACE_ITER_RECORD_TGID;
3391 print_event_info(buf, m);
3393 seq_printf(m, "# TASK-PID %s CPU# TIMESTAMP FUNCTION\n", tgid ? "TGID " : "");
3394 seq_printf(m, "# | | %s | | |\n", tgid ? " | " : "");
3397 static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m,
3400 bool tgid = flags & TRACE_ITER_RECORD_TGID;
3401 const char tgid_space[] = " ";
3402 const char space[] = " ";
3404 print_event_info(buf, m);
3406 seq_printf(m, "# %s _-----=> irqs-off\n",
3407 tgid ? tgid_space : space);
3408 seq_printf(m, "# %s / _----=> need-resched\n",
3409 tgid ? tgid_space : space);
3410 seq_printf(m, "# %s| / _---=> hardirq/softirq\n",
3411 tgid ? tgid_space : space);
3412 seq_printf(m, "# %s|| / _--=> preempt-depth\n",
3413 tgid ? tgid_space : space);
3414 seq_printf(m, "# %s||| / delay\n",
3415 tgid ? tgid_space : space);
3416 seq_printf(m, "# TASK-PID %sCPU# |||| TIMESTAMP FUNCTION\n",
3417 tgid ? " TGID " : space);
3418 seq_printf(m, "# | | %s | |||| | |\n",
3419 tgid ? " | " : space);
3423 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
3425 unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
3426 struct trace_buffer *buf = iter->trace_buffer;
3427 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
3428 struct tracer *type = iter->trace;
3429 unsigned long entries;
3430 unsigned long total;
3431 const char *name = "preemption";
3435 get_total_entries(buf, &total, &entries);
3437 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
3439 seq_puts(m, "# -----------------------------------"
3440 "---------------------------------\n");
3441 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
3442 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
3443 nsecs_to_usecs(data->saved_latency),
3447 #if defined(CONFIG_PREEMPT_NONE)
3449 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
3451 #elif defined(CONFIG_PREEMPT)
3456 /* These are reserved for later use */
3459 seq_printf(m, " #P:%d)\n", num_online_cpus());
3463 seq_puts(m, "# -----------------\n");
3464 seq_printf(m, "# | task: %.16s-%d "
3465 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
3466 data->comm, data->pid,
3467 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
3468 data->policy, data->rt_priority);
3469 seq_puts(m, "# -----------------\n");
3471 if (data->critical_start) {
3472 seq_puts(m, "# => started at: ");
3473 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
3474 trace_print_seq(m, &iter->seq);
3475 seq_puts(m, "\n# => ended at: ");
3476 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
3477 trace_print_seq(m, &iter->seq);
3478 seq_puts(m, "\n#\n");
3484 static void test_cpu_buff_start(struct trace_iterator *iter)
3486 struct trace_seq *s = &iter->seq;
3487 struct trace_array *tr = iter->tr;
3489 if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
3492 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
3495 if (cpumask_available(iter->started) &&
3496 cpumask_test_cpu(iter->cpu, iter->started))
3499 if (per_cpu_ptr(iter->trace_buffer->data, iter->cpu)->skipped_entries)
3502 if (cpumask_available(iter->started))
3503 cpumask_set_cpu(iter->cpu, iter->started);
3505 /* Don't print started cpu buffer for the first entry of the trace */
3507 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
3511 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
3513 struct trace_array *tr = iter->tr;
3514 struct trace_seq *s = &iter->seq;
3515 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
3516 struct trace_entry *entry;
3517 struct trace_event *event;
3521 test_cpu_buff_start(iter);
3523 event = ftrace_find_event(entry->type);
3525 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
3526 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
3527 trace_print_lat_context(iter);
3529 trace_print_context(iter);
3532 if (trace_seq_has_overflowed(s))
3533 return TRACE_TYPE_PARTIAL_LINE;
3536 return event->funcs->trace(iter, sym_flags, event);
3538 trace_seq_printf(s, "Unknown type %d\n", entry->type);
3540 return trace_handle_return(s);
3543 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
3545 struct trace_array *tr = iter->tr;
3546 struct trace_seq *s = &iter->seq;
3547 struct trace_entry *entry;
3548 struct trace_event *event;
3552 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
3553 trace_seq_printf(s, "%d %d %llu ",
3554 entry->pid, iter->cpu, iter->ts);
3556 if (trace_seq_has_overflowed(s))
3557 return TRACE_TYPE_PARTIAL_LINE;
3559 event = ftrace_find_event(entry->type);
3561 return event->funcs->raw(iter, 0, event);
3563 trace_seq_printf(s, "%d ?\n", entry->type);
3565 return trace_handle_return(s);
3568 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
3570 struct trace_array *tr = iter->tr;
3571 struct trace_seq *s = &iter->seq;
3572 unsigned char newline = '\n';
3573 struct trace_entry *entry;
3574 struct trace_event *event;
3578 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
3579 SEQ_PUT_HEX_FIELD(s, entry->pid);
3580 SEQ_PUT_HEX_FIELD(s, iter->cpu);
3581 SEQ_PUT_HEX_FIELD(s, iter->ts);
3582 if (trace_seq_has_overflowed(s))
3583 return TRACE_TYPE_PARTIAL_LINE;
3586 event = ftrace_find_event(entry->type);
3588 enum print_line_t ret = event->funcs->hex(iter, 0, event);
3589 if (ret != TRACE_TYPE_HANDLED)
3593 SEQ_PUT_FIELD(s, newline);
3595 return trace_handle_return(s);
3598 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
3600 struct trace_array *tr = iter->tr;
3601 struct trace_seq *s = &iter->seq;
3602 struct trace_entry *entry;
3603 struct trace_event *event;
3607 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
3608 SEQ_PUT_FIELD(s, entry->pid);
3609 SEQ_PUT_FIELD(s, iter->cpu);
3610 SEQ_PUT_FIELD(s, iter->ts);
3611 if (trace_seq_has_overflowed(s))
3612 return TRACE_TYPE_PARTIAL_LINE;
3615 event = ftrace_find_event(entry->type);
3616 return event ? event->funcs->binary(iter, 0, event) :
3620 int trace_empty(struct trace_iterator *iter)
3622 struct ring_buffer_iter *buf_iter;
3625 /* If we are looking at one CPU buffer, only check that one */
3626 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
3627 cpu = iter->cpu_file;
3628 buf_iter = trace_buffer_iter(iter, cpu);
3630 if (!ring_buffer_iter_empty(buf_iter))
3633 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
3639 for_each_tracing_cpu(cpu) {
3640 buf_iter = trace_buffer_iter(iter, cpu);
3642 if (!ring_buffer_iter_empty(buf_iter))
3645 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
3653 /* Called with trace_event_read_lock() held. */
3654 enum print_line_t print_trace_line(struct trace_iterator *iter)
3656 struct trace_array *tr = iter->tr;
3657 unsigned long trace_flags = tr->trace_flags;
3658 enum print_line_t ret;
3660 if (iter->lost_events) {
3661 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
3662 iter->cpu, iter->lost_events);
3663 if (trace_seq_has_overflowed(&iter->seq))
3664 return TRACE_TYPE_PARTIAL_LINE;
3667 if (iter->trace && iter->trace->print_line) {
3668 ret = iter->trace->print_line(iter);
3669 if (ret != TRACE_TYPE_UNHANDLED)
3673 if (iter->ent->type == TRACE_BPUTS &&
3674 trace_flags & TRACE_ITER_PRINTK &&
3675 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
3676 return trace_print_bputs_msg_only(iter);
3678 if (iter->ent->type == TRACE_BPRINT &&
3679 trace_flags & TRACE_ITER_PRINTK &&
3680 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
3681 return trace_print_bprintk_msg_only(iter);
3683 if (iter->ent->type == TRACE_PRINT &&
3684 trace_flags & TRACE_ITER_PRINTK &&
3685 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
3686 return trace_print_printk_msg_only(iter);
3688 if (trace_flags & TRACE_ITER_BIN)
3689 return print_bin_fmt(iter);
3691 if (trace_flags & TRACE_ITER_HEX)
3692 return print_hex_fmt(iter);
3694 if (trace_flags & TRACE_ITER_RAW)
3695 return print_raw_fmt(iter);
3697 return print_trace_fmt(iter);
3700 void trace_latency_header(struct seq_file *m)
3702 struct trace_iterator *iter = m->private;
3703 struct trace_array *tr = iter->tr;
3705 /* print nothing if the buffers are empty */
3706 if (trace_empty(iter))
3709 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
3710 print_trace_header(m, iter);
3712 if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
3713 print_lat_help_header(m);
3716 void trace_default_header(struct seq_file *m)
3718 struct trace_iterator *iter = m->private;
3719 struct trace_array *tr = iter->tr;
3720 unsigned long trace_flags = tr->trace_flags;
3722 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
3725 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
3726 /* print nothing if the buffers are empty */
3727 if (trace_empty(iter))
3729 print_trace_header(m, iter);
3730 if (!(trace_flags & TRACE_ITER_VERBOSE))
3731 print_lat_help_header(m);
3733 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
3734 if (trace_flags & TRACE_ITER_IRQ_INFO)
3735 print_func_help_header_irq(iter->trace_buffer,
3738 print_func_help_header(iter->trace_buffer, m,
3744 static void test_ftrace_alive(struct seq_file *m)
3746 if (!ftrace_is_dead())
3748 seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
3749 "# MAY BE MISSING FUNCTION EVENTS\n");
3752 #ifdef CONFIG_TRACER_MAX_TRACE
3753 static void show_snapshot_main_help(struct seq_file *m)
3755 seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
3756 "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
3757 "# Takes a snapshot of the main buffer.\n"
3758 "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
3759 "# (Doesn't have to be '2' works with any number that\n"
3760 "# is not a '0' or '1')\n");
3763 static void show_snapshot_percpu_help(struct seq_file *m)
3765 seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
3766 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
3767 seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
3768 "# Takes a snapshot of the main buffer for this cpu.\n");
3770 seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
3771 "# Must use main snapshot file to allocate.\n");
3773 seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
3774 "# (Doesn't have to be '2' works with any number that\n"
3775 "# is not a '0' or '1')\n");
3778 static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
3780 if (iter->tr->allocated_snapshot)
3781 seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
3783 seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
3785 seq_puts(m, "# Snapshot commands:\n");
3786 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
3787 show_snapshot_main_help(m);
3789 show_snapshot_percpu_help(m);
3792 /* Should never be called */
3793 static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
3796 static int s_show(struct seq_file *m, void *v)
3798 struct trace_iterator *iter = v;
3801 if (iter->ent == NULL) {
3803 seq_printf(m, "# tracer: %s\n", iter->trace->name);
3805 test_ftrace_alive(m);
3807 if (iter->snapshot && trace_empty(iter))
3808 print_snapshot_help(m, iter);
3809 else if (iter->trace && iter->trace->print_header)
3810 iter->trace->print_header(m);
3812 trace_default_header(m);
3814 } else if (iter->leftover) {
3816 * If we filled the seq_file buffer earlier, we
3817 * want to just show it now.
3819 ret = trace_print_seq(m, &iter->seq);
3821 /* ret should this time be zero, but you never know */
3822 iter->leftover = ret;
3825 print_trace_line(iter);
3826 ret = trace_print_seq(m, &iter->seq);
3828 * If we overflow the seq_file buffer, then it will
3829 * ask us for this data again at start up.
3831 * ret is 0 if seq_file write succeeded.
3834 iter->leftover = ret;
3841 * Should be used after trace_array_get(), trace_types_lock
3842 * ensures that i_cdev was already initialized.
3844 static inline int tracing_get_cpu(struct inode *inode)
3846 if (inode->i_cdev) /* See trace_create_cpu_file() */
3847 return (long)inode->i_cdev - 1;
3848 return RING_BUFFER_ALL_CPUS;
3851 static const struct seq_operations tracer_seq_ops = {
3858 static struct trace_iterator *
3859 __tracing_open(struct inode *inode, struct file *file, bool snapshot)
3861 struct trace_array *tr = inode->i_private;
3862 struct trace_iterator *iter;
3865 if (tracing_disabled)
3866 return ERR_PTR(-ENODEV);
3868 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
3870 return ERR_PTR(-ENOMEM);
3872 iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
3874 if (!iter->buffer_iter)
3878 * We make a copy of the current tracer to avoid concurrent
3879 * changes on it while we are reading.
3881 mutex_lock(&trace_types_lock);
3882 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
3886 *iter->trace = *tr->current_trace;
3888 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
3893 #ifdef CONFIG_TRACER_MAX_TRACE
3894 /* Currently only the top directory has a snapshot */
3895 if (tr->current_trace->print_max || snapshot)
3896 iter->trace_buffer = &tr->max_buffer;
3899 iter->trace_buffer = &tr->trace_buffer;
3900 iter->snapshot = snapshot;
3902 iter->cpu_file = tracing_get_cpu(inode);
3903 mutex_init(&iter->mutex);
3905 /* Notify the tracer early; before we stop tracing. */
3906 if (iter->trace && iter->trace->open)
3907 iter->trace->open(iter);
3909 /* Annotate start of buffers if we had overruns */
3910 if (ring_buffer_overruns(iter->trace_buffer->buffer))
3911 iter->iter_flags |= TRACE_FILE_ANNOTATE;
3913 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
3914 if (trace_clocks[tr->clock_id].in_ns)
3915 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
3917 /* stop the trace while dumping if we are not opening "snapshot" */
3918 if (!iter->snapshot)
3919 tracing_stop_tr(tr);
3921 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
3922 for_each_tracing_cpu(cpu) {
3923 iter->buffer_iter[cpu] =
3924 ring_buffer_read_prepare(iter->trace_buffer->buffer,
3927 ring_buffer_read_prepare_sync();
3928 for_each_tracing_cpu(cpu) {
3929 ring_buffer_read_start(iter->buffer_iter[cpu]);
3930 tracing_iter_reset(iter, cpu);
3933 cpu = iter->cpu_file;
3934 iter->buffer_iter[cpu] =
3935 ring_buffer_read_prepare(iter->trace_buffer->buffer,
3937 ring_buffer_read_prepare_sync();
3938 ring_buffer_read_start(iter->buffer_iter[cpu]);
3939 tracing_iter_reset(iter, cpu);
3942 mutex_unlock(&trace_types_lock);
3947 mutex_unlock(&trace_types_lock);
3949 kfree(iter->buffer_iter);
3951 seq_release_private(inode, file);
3952 return ERR_PTR(-ENOMEM);
3955 int tracing_open_generic(struct inode *inode, struct file *filp)
3957 if (tracing_disabled)
3960 filp->private_data = inode->i_private;
3964 bool tracing_is_disabled(void)
3966 return (tracing_disabled) ? true: false;
3970 * Open and update trace_array ref count.
3971 * Must have the current trace_array passed to it.
3973 static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
3975 struct trace_array *tr = inode->i_private;
3977 if (tracing_disabled)
3980 if (trace_array_get(tr) < 0)
3983 filp->private_data = inode->i_private;
3988 static int tracing_release(struct inode *inode, struct file *file)
3990 struct trace_array *tr = inode->i_private;
3991 struct seq_file *m = file->private_data;
3992 struct trace_iterator *iter;
3995 if (!(file->f_mode & FMODE_READ)) {
3996 trace_array_put(tr);
4000 /* Writes do not use seq_file */
4002 mutex_lock(&trace_types_lock);
4004 for_each_tracing_cpu(cpu) {
4005 if (iter->buffer_iter[cpu])
4006 ring_buffer_read_finish(iter->buffer_iter[cpu]);
4009 if (iter->trace && iter->trace->close)
4010 iter->trace->close(iter);
4012 if (!iter->snapshot)
4013 /* reenable tracing if it was previously enabled */
4014 tracing_start_tr(tr);
4016 __trace_array_put(tr);
4018 mutex_unlock(&trace_types_lock);
4020 mutex_destroy(&iter->mutex);
4021 free_cpumask_var(iter->started);
4023 kfree(iter->buffer_iter);
4024 seq_release_private(inode, file);
4029 static int tracing_release_generic_tr(struct inode *inode, struct file *file)
4031 struct trace_array *tr = inode->i_private;
4033 trace_array_put(tr);
4037 static int tracing_single_release_tr(struct inode *inode, struct file *file)
4039 struct trace_array *tr = inode->i_private;
4041 trace_array_put(tr);
4043 return single_release(inode, file);
4046 static int tracing_open(struct inode *inode, struct file *file)
4048 struct trace_array *tr = inode->i_private;
4049 struct trace_iterator *iter;
4052 if (trace_array_get(tr) < 0)
4055 /* If this file was open for write, then erase contents */
4056 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
4057 int cpu = tracing_get_cpu(inode);
4058 struct trace_buffer *trace_buf = &tr->trace_buffer;
4060 #ifdef CONFIG_TRACER_MAX_TRACE
4061 if (tr->current_trace->print_max)
4062 trace_buf = &tr->max_buffer;
4065 if (cpu == RING_BUFFER_ALL_CPUS)
4066 tracing_reset_online_cpus(trace_buf);
4068 tracing_reset(trace_buf, cpu);
4071 if (file->f_mode & FMODE_READ) {
4072 iter = __tracing_open(inode, file, false);
4074 ret = PTR_ERR(iter);
4075 else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
4076 iter->iter_flags |= TRACE_FILE_LAT_FMT;
4080 trace_array_put(tr);
4086 * Some tracers are not suitable for instance buffers.
4087 * A tracer is always available for the global array (toplevel)
4088 * or if it explicitly states that it is.
4091 trace_ok_for_array(struct tracer *t, struct trace_array *tr)
4093 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
4096 /* Find the next tracer that this trace array may use */
4097 static struct tracer *
4098 get_tracer_for_array(struct trace_array *tr, struct tracer *t)
4100 while (t && !trace_ok_for_array(t, tr))
4107 t_next(struct seq_file *m, void *v, loff_t *pos)
4109 struct trace_array *tr = m->private;
4110 struct tracer *t = v;
4115 t = get_tracer_for_array(tr, t->next);
4120 static void *t_start(struct seq_file *m, loff_t *pos)
4122 struct trace_array *tr = m->private;
4126 mutex_lock(&trace_types_lock);
4128 t = get_tracer_for_array(tr, trace_types);
4129 for (; t && l < *pos; t = t_next(m, t, &l))
4135 static void t_stop(struct seq_file *m, void *p)
4137 mutex_unlock(&trace_types_lock);
4140 static int t_show(struct seq_file *m, void *v)
4142 struct tracer *t = v;
4147 seq_puts(m, t->name);
4156 static const struct seq_operations show_traces_seq_ops = {
4163 static int show_traces_open(struct inode *inode, struct file *file)
4165 struct trace_array *tr = inode->i_private;
4169 if (tracing_disabled)
4172 if (trace_array_get(tr) < 0)
4175 ret = seq_open(file, &show_traces_seq_ops);
4177 trace_array_put(tr);
4181 m = file->private_data;
4187 static int show_traces_release(struct inode *inode, struct file *file)
4189 struct trace_array *tr = inode->i_private;
4191 trace_array_put(tr);
4192 return seq_release(inode, file);
4196 tracing_write_stub(struct file *filp, const char __user *ubuf,
4197 size_t count, loff_t *ppos)
4202 loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
4206 if (file->f_mode & FMODE_READ)
4207 ret = seq_lseek(file, offset, whence);
4209 file->f_pos = ret = 0;
4214 static const struct file_operations tracing_fops = {
4215 .open = tracing_open,
4217 .write = tracing_write_stub,
4218 .llseek = tracing_lseek,
4219 .release = tracing_release,
4222 static const struct file_operations show_traces_fops = {
4223 .open = show_traces_open,
4225 .llseek = seq_lseek,
4226 .release = show_traces_release,
4230 tracing_cpumask_read(struct file *filp, char __user *ubuf,
4231 size_t count, loff_t *ppos)
4233 struct trace_array *tr = file_inode(filp)->i_private;
4237 len = snprintf(NULL, 0, "%*pb\n",
4238 cpumask_pr_args(tr->tracing_cpumask)) + 1;
4239 mask_str = kmalloc(len, GFP_KERNEL);
4243 len = snprintf(mask_str, len, "%*pb\n",
4244 cpumask_pr_args(tr->tracing_cpumask));
4249 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
4258 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
4259 size_t count, loff_t *ppos)
4261 struct trace_array *tr = file_inode(filp)->i_private;
4262 cpumask_var_t tracing_cpumask_new;
4265 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
4268 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
4272 local_irq_disable();
4273 arch_spin_lock(&tr->max_lock);
4274 for_each_tracing_cpu(cpu) {
4276 * Increase/decrease the disabled counter if we are
4277 * about to flip a bit in the cpumask:
4279 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
4280 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
4281 atomic_inc(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
4282 ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu);
4284 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
4285 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
4286 atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
4287 ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
4290 arch_spin_unlock(&tr->max_lock);
4293 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
4294 free_cpumask_var(tracing_cpumask_new);
4299 free_cpumask_var(tracing_cpumask_new);
4304 static const struct file_operations tracing_cpumask_fops = {
4305 .open = tracing_open_generic_tr,
4306 .read = tracing_cpumask_read,
4307 .write = tracing_cpumask_write,
4308 .release = tracing_release_generic_tr,
4309 .llseek = generic_file_llseek,
4312 static int tracing_trace_options_show(struct seq_file *m, void *v)
4314 struct tracer_opt *trace_opts;
4315 struct trace_array *tr = m->private;
4319 mutex_lock(&trace_types_lock);
4320 tracer_flags = tr->current_trace->flags->val;
4321 trace_opts = tr->current_trace->flags->opts;
4323 for (i = 0; trace_options[i]; i++) {
4324 if (tr->trace_flags & (1 << i))
4325 seq_printf(m, "%s\n", trace_options[i]);
4327 seq_printf(m, "no%s\n", trace_options[i]);
4330 for (i = 0; trace_opts[i].name; i++) {
4331 if (tracer_flags & trace_opts[i].bit)
4332 seq_printf(m, "%s\n", trace_opts[i].name);
4334 seq_printf(m, "no%s\n", trace_opts[i].name);
4336 mutex_unlock(&trace_types_lock);
4341 static int __set_tracer_option(struct trace_array *tr,
4342 struct tracer_flags *tracer_flags,
4343 struct tracer_opt *opts, int neg)
4345 struct tracer *trace = tracer_flags->trace;
4348 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
4353 tracer_flags->val &= ~opts->bit;
4355 tracer_flags->val |= opts->bit;
4359 /* Try to assign a tracer specific option */
4360 static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
4362 struct tracer *trace = tr->current_trace;
4363 struct tracer_flags *tracer_flags = trace->flags;
4364 struct tracer_opt *opts = NULL;
4367 for (i = 0; tracer_flags->opts[i].name; i++) {
4368 opts = &tracer_flags->opts[i];
4370 if (strcmp(cmp, opts->name) == 0)
4371 return __set_tracer_option(tr, trace->flags, opts, neg);
4377 /* Some tracers require overwrite to stay enabled */
4378 int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
4380 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
4386 int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
4390 if ((mask == TRACE_ITER_RECORD_TGID) ||
4391 (mask == TRACE_ITER_RECORD_CMD))
4392 lockdep_assert_held(&event_mutex);
4394 /* do nothing if flag is already set */
4395 if (!!(tr->trace_flags & mask) == !!enabled)
4398 /* Give the tracer a chance to approve the change */
4399 if (tr->current_trace->flag_changed)
4400 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
4404 tr->trace_flags |= mask;
4406 tr->trace_flags &= ~mask;
4408 if (mask == TRACE_ITER_RECORD_CMD)
4409 trace_event_enable_cmd_record(enabled);
4411 if (mask == TRACE_ITER_RECORD_TGID) {
4413 tgid_map_max = pid_max;
4414 map = kvcalloc(tgid_map_max + 1, sizeof(*tgid_map),
4418 * Pairs with smp_load_acquire() in
4419 * trace_find_tgid_ptr() to ensure that if it observes
4420 * the tgid_map we just allocated then it also observes
4421 * the corresponding tgid_map_max value.
4423 smp_store_release(&tgid_map, map);
4426 tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
4430 trace_event_enable_tgid_record(enabled);
4433 if (mask == TRACE_ITER_EVENT_FORK)
4434 trace_event_follow_fork(tr, enabled);
4436 if (mask == TRACE_ITER_FUNC_FORK)
4437 ftrace_pid_follow_fork(tr, enabled);
4439 if (mask == TRACE_ITER_OVERWRITE) {
4440 ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled);
4441 #ifdef CONFIG_TRACER_MAX_TRACE
4442 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
4446 if (mask == TRACE_ITER_PRINTK) {
4447 trace_printk_start_stop_comm(enabled);
4448 trace_printk_control(enabled);
4454 static int trace_set_options(struct trace_array *tr, char *option)
4459 size_t orig_len = strlen(option);
4461 cmp = strstrip(option);
4463 if (strncmp(cmp, "no", 2) == 0) {
4468 mutex_lock(&event_mutex);
4469 mutex_lock(&trace_types_lock);
4471 ret = match_string(trace_options, -1, cmp);
4472 /* If no option could be set, test the specific tracer options */
4474 ret = set_tracer_option(tr, cmp, neg);
4476 ret = set_tracer_flag(tr, 1 << ret, !neg);
4478 mutex_unlock(&trace_types_lock);
4479 mutex_unlock(&event_mutex);
4482 * If the first trailing whitespace is replaced with '\0' by strstrip,
4483 * turn it back into a space.
4485 if (orig_len > strlen(option))
4486 option[strlen(option)] = ' ';
4491 static void __init apply_trace_boot_options(void)
4493 char *buf = trace_boot_options_buf;
4497 option = strsep(&buf, ",");
4503 trace_set_options(&global_trace, option);
4505 /* Put back the comma to allow this to be called again */
4512 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
4513 size_t cnt, loff_t *ppos)
4515 struct seq_file *m = filp->private_data;
4516 struct trace_array *tr = m->private;
4520 if (cnt >= sizeof(buf))
4523 if (copy_from_user(buf, ubuf, cnt))
4528 ret = trace_set_options(tr, buf);
4537 static int tracing_trace_options_open(struct inode *inode, struct file *file)
4539 struct trace_array *tr = inode->i_private;
4542 if (tracing_disabled)
4545 if (trace_array_get(tr) < 0)
4548 ret = single_open(file, tracing_trace_options_show, inode->i_private);
4550 trace_array_put(tr);
4555 static const struct file_operations tracing_iter_fops = {
4556 .open = tracing_trace_options_open,
4558 .llseek = seq_lseek,
4559 .release = tracing_single_release_tr,
4560 .write = tracing_trace_options_write,
4563 static const char readme_msg[] =
4564 "tracing mini-HOWTO:\n\n"
4565 "# echo 0 > tracing_on : quick way to disable tracing\n"
4566 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
4567 " Important files:\n"
4568 " trace\t\t\t- The static contents of the buffer\n"
4569 "\t\t\t To clear the buffer write into this file: echo > trace\n"
4570 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
4571 " current_tracer\t- function and latency tracers\n"
4572 " available_tracers\t- list of configured tracers for current_tracer\n"
4573 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
4574 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
4575 " trace_clock\t\t-change the clock used to order events\n"
4576 " local: Per cpu clock but may not be synced across CPUs\n"
4577 " global: Synced across CPUs but slows tracing down.\n"
4578 " counter: Not a clock, but just an increment\n"
4579 " uptime: Jiffy counter from time of boot\n"
4580 " perf: Same clock that perf events use\n"
4581 #ifdef CONFIG_X86_64
4582 " x86-tsc: TSC cycle counter\n"
4584 "\n timestamp_mode\t-view the mode used to timestamp events\n"
4585 " delta: Delta difference against a buffer-wide timestamp\n"
4586 " absolute: Absolute (standalone) timestamp\n"
4587 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
4588 "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
4589 " tracing_cpumask\t- Limit which CPUs to trace\n"
4590 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
4591 "\t\t\t Remove sub-buffer with rmdir\n"
4592 " trace_options\t\t- Set format or modify how tracing happens\n"
4593 "\t\t\t Disable an option by adding a suffix 'no' to the\n"
4594 "\t\t\t option name\n"
4595 " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
4596 #ifdef CONFIG_DYNAMIC_FTRACE
4597 "\n available_filter_functions - list of functions that can be filtered on\n"
4598 " set_ftrace_filter\t- echo function name in here to only trace these\n"
4599 "\t\t\t functions\n"
4600 "\t accepts: func_full_name or glob-matching-pattern\n"
4601 "\t modules: Can select a group via module\n"
4602 "\t Format: :mod:<module-name>\n"
4603 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
4604 "\t triggers: a command to perform when function is hit\n"
4605 "\t Format: <function>:<trigger>[:count]\n"
4606 "\t trigger: traceon, traceoff\n"
4607 "\t\t enable_event:<system>:<event>\n"
4608 "\t\t disable_event:<system>:<event>\n"
4609 #ifdef CONFIG_STACKTRACE
4612 #ifdef CONFIG_TRACER_SNAPSHOT
4617 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
4618 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
4619 "\t The first one will disable tracing every time do_fault is hit\n"
4620 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
4621 "\t The first time do trap is hit and it disables tracing, the\n"
4622 "\t counter will decrement to 2. If tracing is already disabled,\n"
4623 "\t the counter will not decrement. It only decrements when the\n"
4624 "\t trigger did work\n"
4625 "\t To remove trigger without count:\n"
4626 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
4627 "\t To remove trigger with a count:\n"
4628 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
4629 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
4630 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
4631 "\t modules: Can select a group via module command :mod:\n"
4632 "\t Does not accept triggers\n"
4633 #endif /* CONFIG_DYNAMIC_FTRACE */
4634 #ifdef CONFIG_FUNCTION_TRACER
4635 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
4638 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4639 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
4640 " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
4641 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
4643 #ifdef CONFIG_TRACER_SNAPSHOT
4644 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
4645 "\t\t\t snapshot buffer. Read the contents for more\n"
4646 "\t\t\t information\n"
4648 #ifdef CONFIG_STACK_TRACER
4649 " stack_trace\t\t- Shows the max stack trace when active\n"
4650 " stack_max_size\t- Shows current max stack size that was traced\n"
4651 "\t\t\t Write into this file to reset the max size (trigger a\n"
4652 "\t\t\t new trace)\n"
4653 #ifdef CONFIG_DYNAMIC_FTRACE
4654 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
4657 #endif /* CONFIG_STACK_TRACER */
4658 #ifdef CONFIG_KPROBE_EVENTS
4659 " kprobe_events\t\t- Add/remove/show the kernel dynamic events\n"
4660 "\t\t\t Write into this file to define/undefine new trace events.\n"
4662 #ifdef CONFIG_UPROBE_EVENTS
4663 " uprobe_events\t\t- Add/remove/show the userspace dynamic events\n"
4664 "\t\t\t Write into this file to define/undefine new trace events.\n"
4666 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
4667 "\t accepts: event-definitions (one definition per line)\n"
4668 "\t Format: p[:[<group>/]<event>] <place> [<args>]\n"
4669 "\t r[maxactive][:[<group>/]<event>] <place> [<args>]\n"
4670 "\t -:[<group>/]<event>\n"
4671 #ifdef CONFIG_KPROBE_EVENTS
4672 "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
4673 "place (kretprobe): [<module>:]<symbol>[+<offset>]|<memaddr>\n"
4675 #ifdef CONFIG_UPROBE_EVENTS
4676 "\t place: <path>:<offset>\n"
4678 "\t args: <name>=fetcharg[:type]\n"
4679 "\t fetcharg: %<register>, @<address>, @<symbol>[+|-<offset>],\n"
4680 "\t $stack<index>, $stack, $retval, $comm\n"
4681 "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string,\n"
4682 "\t b<bit-width>@<bit-offset>/<container-size>\n"
4684 " events/\t\t- Directory containing all trace event subsystems:\n"
4685 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
4686 " events/<system>/\t- Directory containing all trace events for <system>:\n"
4687 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
4689 " filter\t\t- If set, only events passing filter are traced\n"
4690 " events/<system>/<event>/\t- Directory containing control files for\n"
4692 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
4693 " filter\t\t- If set, only events passing filter are traced\n"
4694 " trigger\t\t- If set, a command to perform when event is hit\n"
4695 "\t Format: <trigger>[:count][if <filter>]\n"
4696 "\t trigger: traceon, traceoff\n"
4697 "\t enable_event:<system>:<event>\n"
4698 "\t disable_event:<system>:<event>\n"
4699 #ifdef CONFIG_HIST_TRIGGERS
4700 "\t enable_hist:<system>:<event>\n"
4701 "\t disable_hist:<system>:<event>\n"
4703 #ifdef CONFIG_STACKTRACE
4706 #ifdef CONFIG_TRACER_SNAPSHOT
4709 #ifdef CONFIG_HIST_TRIGGERS
4710 "\t\t hist (see below)\n"
4712 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
4713 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
4714 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
4715 "\t events/block/block_unplug/trigger\n"
4716 "\t The first disables tracing every time block_unplug is hit.\n"
4717 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
4718 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
4719 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
4720 "\t Like function triggers, the counter is only decremented if it\n"
4721 "\t enabled or disabled tracing.\n"
4722 "\t To remove a trigger without a count:\n"
4723 "\t echo '!<trigger> > <system>/<event>/trigger\n"
4724 "\t To remove a trigger with a count:\n"
4725 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
4726 "\t Filters can be ignored when removing a trigger.\n"
4727 #ifdef CONFIG_HIST_TRIGGERS
4728 " hist trigger\t- If set, event hits are aggregated into a hash table\n"
4729 "\t Format: hist:keys=<field1[,field2,...]>\n"
4730 "\t [:values=<field1[,field2,...]>]\n"
4731 "\t [:sort=<field1[,field2,...]>]\n"
4732 "\t [:size=#entries]\n"
4733 "\t [:pause][:continue][:clear]\n"
4734 "\t [:name=histname1]\n"
4735 "\t [if <filter>]\n\n"
4736 "\t Note, special fields can be used as well:\n"
4737 "\t common_timestamp - to record current timestamp\n"
4738 "\t common_cpu - to record the CPU the event happened on\n"
4740 "\t When a matching event is hit, an entry is added to a hash\n"
4741 "\t table using the key(s) and value(s) named, and the value of a\n"
4742 "\t sum called 'hitcount' is incremented. Keys and values\n"
4743 "\t correspond to fields in the event's format description. Keys\n"
4744 "\t can be any field, or the special string 'stacktrace'.\n"
4745 "\t Compound keys consisting of up to two fields can be specified\n"
4746 "\t by the 'keys' keyword. Values must correspond to numeric\n"
4747 "\t fields. Sort keys consisting of up to two fields can be\n"
4748 "\t specified using the 'sort' keyword. The sort direction can\n"
4749 "\t be modified by appending '.descending' or '.ascending' to a\n"
4750 "\t sort field. The 'size' parameter can be used to specify more\n"
4751 "\t or fewer than the default 2048 entries for the hashtable size.\n"
4752 "\t If a hist trigger is given a name using the 'name' parameter,\n"
4753 "\t its histogram data will be shared with other triggers of the\n"
4754 "\t same name, and trigger hits will update this common data.\n\n"
4755 "\t Reading the 'hist' file for the event will dump the hash\n"
4756 "\t table in its entirety to stdout. If there are multiple hist\n"
4757 "\t triggers attached to an event, there will be a table for each\n"
4758 "\t trigger in the output. The table displayed for a named\n"
4759 "\t trigger will be the same as any other instance having the\n"
4760 "\t same name. The default format used to display a given field\n"
4761 "\t can be modified by appending any of the following modifiers\n"
4762 "\t to the field name, as applicable:\n\n"
4763 "\t .hex display a number as a hex value\n"
4764 "\t .sym display an address as a symbol\n"
4765 "\t .sym-offset display an address as a symbol and offset\n"
4766 "\t .execname display a common_pid as a program name\n"
4767 "\t .syscall display a syscall id as a syscall name\n"
4768 "\t .log2 display log2 value rather than raw number\n"
4769 "\t .usecs display a common_timestamp in microseconds\n\n"
4770 "\t The 'pause' parameter can be used to pause an existing hist\n"
4771 "\t trigger or to start a hist trigger but not log any events\n"
4772 "\t until told to do so. 'continue' can be used to start or\n"
4773 "\t restart a paused hist trigger.\n\n"
4774 "\t The 'clear' parameter will clear the contents of a running\n"
4775 "\t hist trigger and leave its current paused/active state\n"
4777 "\t The enable_hist and disable_hist triggers can be used to\n"
4778 "\t have one event conditionally start and stop another event's\n"
4779 "\t already-attached hist trigger. The syntax is analagous to\n"
4780 "\t the enable_event and disable_event triggers.\n"
4785 tracing_readme_read(struct file *filp, char __user *ubuf,
4786 size_t cnt, loff_t *ppos)
4788 return simple_read_from_buffer(ubuf, cnt, ppos,
4789 readme_msg, strlen(readme_msg));
4792 static const struct file_operations tracing_readme_fops = {
4793 .open = tracing_open_generic,
4794 .read = tracing_readme_read,
4795 .llseek = generic_file_llseek,
4798 static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos)
4802 return trace_find_tgid_ptr(pid);
4805 static void *saved_tgids_start(struct seq_file *m, loff_t *pos)
4809 return trace_find_tgid_ptr(pid);
4812 static void saved_tgids_stop(struct seq_file *m, void *v)
4816 static int saved_tgids_show(struct seq_file *m, void *v)
4818 int *entry = (int *)v;
4819 int pid = entry - tgid_map;
4825 seq_printf(m, "%d %d\n", pid, tgid);
4829 static const struct seq_operations tracing_saved_tgids_seq_ops = {
4830 .start = saved_tgids_start,
4831 .stop = saved_tgids_stop,
4832 .next = saved_tgids_next,
4833 .show = saved_tgids_show,
4836 static int tracing_saved_tgids_open(struct inode *inode, struct file *filp)
4838 if (tracing_disabled)
4841 return seq_open(filp, &tracing_saved_tgids_seq_ops);
4845 static const struct file_operations tracing_saved_tgids_fops = {
4846 .open = tracing_saved_tgids_open,
4848 .llseek = seq_lseek,
4849 .release = seq_release,
4852 static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
4854 unsigned int *ptr = v;
4856 if (*pos || m->count)
4861 for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
4863 if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
4872 static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
4878 arch_spin_lock(&trace_cmdline_lock);
4880 v = &savedcmd->map_cmdline_to_pid[0];
4882 v = saved_cmdlines_next(m, v, &l);
4890 static void saved_cmdlines_stop(struct seq_file *m, void *v)
4892 arch_spin_unlock(&trace_cmdline_lock);
4896 static int saved_cmdlines_show(struct seq_file *m, void *v)
4898 char buf[TASK_COMM_LEN];
4899 unsigned int *pid = v;
4901 __trace_find_cmdline(*pid, buf);
4902 seq_printf(m, "%d %s\n", *pid, buf);
4906 static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
4907 .start = saved_cmdlines_start,
4908 .next = saved_cmdlines_next,
4909 .stop = saved_cmdlines_stop,
4910 .show = saved_cmdlines_show,
4913 static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
4915 if (tracing_disabled)
4918 return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
4921 static const struct file_operations tracing_saved_cmdlines_fops = {
4922 .open = tracing_saved_cmdlines_open,
4924 .llseek = seq_lseek,
4925 .release = seq_release,
4929 tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
4930 size_t cnt, loff_t *ppos)
4935 arch_spin_lock(&trace_cmdline_lock);
4936 r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
4937 arch_spin_unlock(&trace_cmdline_lock);
4939 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4942 static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
4944 kfree(s->saved_cmdlines);
4945 kfree(s->map_cmdline_to_pid);
4949 static int tracing_resize_saved_cmdlines(unsigned int val)
4951 struct saved_cmdlines_buffer *s, *savedcmd_temp;
4953 s = kmalloc(sizeof(*s), GFP_KERNEL);
4957 if (allocate_cmdlines_buffer(val, s) < 0) {
4962 arch_spin_lock(&trace_cmdline_lock);
4963 savedcmd_temp = savedcmd;
4965 arch_spin_unlock(&trace_cmdline_lock);
4966 free_saved_cmdlines_buffer(savedcmd_temp);
4972 tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
4973 size_t cnt, loff_t *ppos)
4978 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4982 /* must have at least 1 entry or less than PID_MAX_DEFAULT */
4983 if (!val || val > PID_MAX_DEFAULT)
4986 ret = tracing_resize_saved_cmdlines((unsigned int)val);
4995 static const struct file_operations tracing_saved_cmdlines_size_fops = {
4996 .open = tracing_open_generic,
4997 .read = tracing_saved_cmdlines_size_read,
4998 .write = tracing_saved_cmdlines_size_write,
5001 #ifdef CONFIG_TRACE_EVAL_MAP_FILE
5002 static union trace_eval_map_item *
5003 update_eval_map(union trace_eval_map_item *ptr)
5005 if (!ptr->map.eval_string) {
5006 if (ptr->tail.next) {
5007 ptr = ptr->tail.next;
5008 /* Set ptr to the next real item (skip head) */
5016 static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
5018 union trace_eval_map_item *ptr = v;
5021 * Paranoid! If ptr points to end, we don't want to increment past it.
5022 * This really should never happen.
5024 ptr = update_eval_map(ptr);
5025 if (WARN_ON_ONCE(!ptr))
5032 ptr = update_eval_map(ptr);
5037 static void *eval_map_start(struct seq_file *m, loff_t *pos)
5039 union trace_eval_map_item *v;
5042 mutex_lock(&trace_eval_mutex);
5044 v = trace_eval_maps;
5048 while (v && l < *pos) {
5049 v = eval_map_next(m, v, &l);
5055 static void eval_map_stop(struct seq_file *m, void *v)
5057 mutex_unlock(&trace_eval_mutex);
5060 static int eval_map_show(struct seq_file *m, void *v)
5062 union trace_eval_map_item *ptr = v;
5064 seq_printf(m, "%s %ld (%s)\n",
5065 ptr->map.eval_string, ptr->map.eval_value,
5071 static const struct seq_operations tracing_eval_map_seq_ops = {
5072 .start = eval_map_start,
5073 .next = eval_map_next,
5074 .stop = eval_map_stop,
5075 .show = eval_map_show,
5078 static int tracing_eval_map_open(struct inode *inode, struct file *filp)
5080 if (tracing_disabled)
5083 return seq_open(filp, &tracing_eval_map_seq_ops);
5086 static const struct file_operations tracing_eval_map_fops = {
5087 .open = tracing_eval_map_open,
5089 .llseek = seq_lseek,
5090 .release = seq_release,
5093 static inline union trace_eval_map_item *
5094 trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
5096 /* Return tail of array given the head */
5097 return ptr + ptr->head.length + 1;
5101 trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
5104 struct trace_eval_map **stop;
5105 struct trace_eval_map **map;
5106 union trace_eval_map_item *map_array;
5107 union trace_eval_map_item *ptr;
5112 * The trace_eval_maps contains the map plus a head and tail item,
5113 * where the head holds the module and length of array, and the
5114 * tail holds a pointer to the next list.
5116 map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
5118 pr_warn("Unable to allocate trace eval mapping\n");
5122 mutex_lock(&trace_eval_mutex);
5124 if (!trace_eval_maps)
5125 trace_eval_maps = map_array;
5127 ptr = trace_eval_maps;
5129 ptr = trace_eval_jmp_to_tail(ptr);
5130 if (!ptr->tail.next)
5132 ptr = ptr->tail.next;
5135 ptr->tail.next = map_array;
5137 map_array->head.mod = mod;
5138 map_array->head.length = len;
5141 for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
5142 map_array->map = **map;
5145 memset(map_array, 0, sizeof(*map_array));
5147 mutex_unlock(&trace_eval_mutex);
5150 static void trace_create_eval_file(struct dentry *d_tracer)
5152 trace_create_file("eval_map", 0444, d_tracer,
5153 NULL, &tracing_eval_map_fops);
5156 #else /* CONFIG_TRACE_EVAL_MAP_FILE */
5157 static inline void trace_create_eval_file(struct dentry *d_tracer) { }
5158 static inline void trace_insert_eval_map_file(struct module *mod,
5159 struct trace_eval_map **start, int len) { }
5160 #endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
5162 static void trace_insert_eval_map(struct module *mod,
5163 struct trace_eval_map **start, int len)
5165 struct trace_eval_map **map;
5172 trace_event_eval_update(map, len);
5174 trace_insert_eval_map_file(mod, start, len);
5178 tracing_set_trace_read(struct file *filp, char __user *ubuf,
5179 size_t cnt, loff_t *ppos)
5181 struct trace_array *tr = filp->private_data;
5182 char buf[MAX_TRACER_SIZE+2];
5185 mutex_lock(&trace_types_lock);
5186 r = sprintf(buf, "%s\n", tr->current_trace->name);
5187 mutex_unlock(&trace_types_lock);
5189 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5192 int tracer_init(struct tracer *t, struct trace_array *tr)
5194 tracing_reset_online_cpus(&tr->trace_buffer);
5198 static void set_buffer_entries(struct trace_buffer *buf, unsigned long val)
5202 for_each_tracing_cpu(cpu)
5203 per_cpu_ptr(buf->data, cpu)->entries = val;
5206 #ifdef CONFIG_TRACER_MAX_TRACE
5207 /* resize @tr's buffer to the size of @size_tr's entries */
5208 static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
5209 struct trace_buffer *size_buf, int cpu_id)
5213 if (cpu_id == RING_BUFFER_ALL_CPUS) {
5214 for_each_tracing_cpu(cpu) {
5215 ret = ring_buffer_resize(trace_buf->buffer,
5216 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
5219 per_cpu_ptr(trace_buf->data, cpu)->entries =
5220 per_cpu_ptr(size_buf->data, cpu)->entries;
5223 ret = ring_buffer_resize(trace_buf->buffer,
5224 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
5226 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
5227 per_cpu_ptr(size_buf->data, cpu_id)->entries;
5232 #endif /* CONFIG_TRACER_MAX_TRACE */
5234 static int __tracing_resize_ring_buffer(struct trace_array *tr,
5235 unsigned long size, int cpu)
5240 * If kernel or user changes the size of the ring buffer
5241 * we use the size that was given, and we can forget about
5242 * expanding it later.
5244 ring_buffer_expanded = true;
5246 /* May be called before buffers are initialized */
5247 if (!tr->trace_buffer.buffer)
5250 ret = ring_buffer_resize(tr->trace_buffer.buffer, size, cpu);
5254 #ifdef CONFIG_TRACER_MAX_TRACE
5255 if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
5256 !tr->current_trace->use_max_tr)
5259 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
5261 int r = resize_buffer_duplicate_size(&tr->trace_buffer,
5262 &tr->trace_buffer, cpu);
5265 * AARGH! We are left with different
5266 * size max buffer!!!!
5267 * The max buffer is our "snapshot" buffer.
5268 * When a tracer needs a snapshot (one of the
5269 * latency tracers), it swaps the max buffer
5270 * with the saved snap shot. We succeeded to
5271 * update the size of the main buffer, but failed to
5272 * update the size of the max buffer. But when we tried
5273 * to reset the main buffer to the original size, we
5274 * failed there too. This is very unlikely to
5275 * happen, but if it does, warn and kill all
5279 tracing_disabled = 1;
5284 if (cpu == RING_BUFFER_ALL_CPUS)
5285 set_buffer_entries(&tr->max_buffer, size);
5287 per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
5290 #endif /* CONFIG_TRACER_MAX_TRACE */
5292 if (cpu == RING_BUFFER_ALL_CPUS)
5293 set_buffer_entries(&tr->trace_buffer, size);
5295 per_cpu_ptr(tr->trace_buffer.data, cpu)->entries = size;
5300 static ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
5301 unsigned long size, int cpu_id)
5305 mutex_lock(&trace_types_lock);
5307 if (cpu_id != RING_BUFFER_ALL_CPUS) {
5308 /* make sure, this cpu is enabled in the mask */
5309 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
5315 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
5320 mutex_unlock(&trace_types_lock);
5327 * tracing_update_buffers - used by tracing facility to expand ring buffers
5329 * To save on memory when the tracing is never used on a system with it
5330 * configured in. The ring buffers are set to a minimum size. But once
5331 * a user starts to use the tracing facility, then they need to grow
5332 * to their default size.
5334 * This function is to be called when a tracer is about to be used.
5336 int tracing_update_buffers(void)
5340 mutex_lock(&trace_types_lock);
5341 if (!ring_buffer_expanded)
5342 ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
5343 RING_BUFFER_ALL_CPUS);
5344 mutex_unlock(&trace_types_lock);
5349 struct trace_option_dentry;
5352 create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
5355 * Used to clear out the tracer before deletion of an instance.
5356 * Must have trace_types_lock held.
5358 static void tracing_set_nop(struct trace_array *tr)
5360 if (tr->current_trace == &nop_trace)
5363 tr->current_trace->enabled--;
5365 if (tr->current_trace->reset)
5366 tr->current_trace->reset(tr);
5368 tr->current_trace = &nop_trace;
5371 static void add_tracer_options(struct trace_array *tr, struct tracer *t)
5373 /* Only enable if the directory has been created already. */
5377 create_trace_option_files(tr, t);
5380 static int tracing_set_tracer(struct trace_array *tr, const char *buf)
5383 #ifdef CONFIG_TRACER_MAX_TRACE
5388 mutex_lock(&trace_types_lock);
5390 if (!ring_buffer_expanded) {
5391 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
5392 RING_BUFFER_ALL_CPUS);
5398 for (t = trace_types; t; t = t->next) {
5399 if (strcmp(t->name, buf) == 0)
5406 if (t == tr->current_trace)
5409 /* Some tracers won't work on kernel command line */
5410 if (system_state < SYSTEM_RUNNING && t->noboot) {
5411 pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
5416 /* Some tracers are only allowed for the top level buffer */
5417 if (!trace_ok_for_array(t, tr)) {
5422 /* If trace pipe files are being read, we can't change the tracer */
5423 if (tr->current_trace->ref) {
5428 trace_branch_disable();
5430 tr->current_trace->enabled--;
5432 if (tr->current_trace->reset)
5433 tr->current_trace->reset(tr);
5435 /* Current trace needs to be nop_trace before synchronize_sched */
5436 tr->current_trace = &nop_trace;
5438 #ifdef CONFIG_TRACER_MAX_TRACE
5439 had_max_tr = tr->allocated_snapshot;
5441 if (had_max_tr && !t->use_max_tr) {
5443 * We need to make sure that the update_max_tr sees that
5444 * current_trace changed to nop_trace to keep it from
5445 * swapping the buffers after we resize it.
5446 * The update_max_tr is called from interrupts disabled
5447 * so a synchronized_sched() is sufficient.
5449 synchronize_sched();
5454 #ifdef CONFIG_TRACER_MAX_TRACE
5455 if (t->use_max_tr && !had_max_tr) {
5456 ret = tracing_alloc_snapshot_instance(tr);
5463 ret = tracer_init(t, tr);
5468 tr->current_trace = t;
5469 tr->current_trace->enabled++;
5470 trace_branch_enable(tr);
5472 mutex_unlock(&trace_types_lock);
5478 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
5479 size_t cnt, loff_t *ppos)
5481 struct trace_array *tr = filp->private_data;
5482 char buf[MAX_TRACER_SIZE+1];
5489 if (cnt > MAX_TRACER_SIZE)
5490 cnt = MAX_TRACER_SIZE;
5492 if (copy_from_user(buf, ubuf, cnt))
5497 /* strip ending whitespace. */
5498 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
5501 err = tracing_set_tracer(tr, buf);
5511 tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
5512 size_t cnt, loff_t *ppos)
5517 r = snprintf(buf, sizeof(buf), "%ld\n",
5518 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
5519 if (r > sizeof(buf))
5521 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5525 tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
5526 size_t cnt, loff_t *ppos)
5531 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5541 tracing_thresh_read(struct file *filp, char __user *ubuf,
5542 size_t cnt, loff_t *ppos)
5544 return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
5548 tracing_thresh_write(struct file *filp, const char __user *ubuf,
5549 size_t cnt, loff_t *ppos)
5551 struct trace_array *tr = filp->private_data;
5554 mutex_lock(&trace_types_lock);
5555 ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
5559 if (tr->current_trace->update_thresh) {
5560 ret = tr->current_trace->update_thresh(tr);
5567 mutex_unlock(&trace_types_lock);
5572 #if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
5575 tracing_max_lat_read(struct file *filp, char __user *ubuf,
5576 size_t cnt, loff_t *ppos)
5578 return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);
5582 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
5583 size_t cnt, loff_t *ppos)
5585 return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
5590 static int tracing_open_pipe(struct inode *inode, struct file *filp)
5592 struct trace_array *tr = inode->i_private;
5593 struct trace_iterator *iter;
5596 if (tracing_disabled)
5599 if (trace_array_get(tr) < 0)
5602 mutex_lock(&trace_types_lock);
5604 /* create a buffer to store the information to pass to userspace */
5605 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
5608 __trace_array_put(tr);
5612 trace_seq_init(&iter->seq);
5613 iter->trace = tr->current_trace;
5615 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
5620 /* trace pipe does not show start of buffer */
5621 cpumask_setall(iter->started);
5623 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
5624 iter->iter_flags |= TRACE_FILE_LAT_FMT;
5626 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
5627 if (trace_clocks[tr->clock_id].in_ns)
5628 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
5631 iter->trace_buffer = &tr->trace_buffer;
5632 iter->cpu_file = tracing_get_cpu(inode);
5633 mutex_init(&iter->mutex);
5634 filp->private_data = iter;
5636 if (iter->trace->pipe_open)
5637 iter->trace->pipe_open(iter);
5639 nonseekable_open(inode, filp);
5641 tr->current_trace->ref++;
5643 mutex_unlock(&trace_types_lock);
5648 __trace_array_put(tr);
5649 mutex_unlock(&trace_types_lock);
5653 static int tracing_release_pipe(struct inode *inode, struct file *file)
5655 struct trace_iterator *iter = file->private_data;
5656 struct trace_array *tr = inode->i_private;
5658 mutex_lock(&trace_types_lock);
5660 tr->current_trace->ref--;
5662 if (iter->trace->pipe_close)
5663 iter->trace->pipe_close(iter);
5665 mutex_unlock(&trace_types_lock);
5667 free_cpumask_var(iter->started);
5668 mutex_destroy(&iter->mutex);
5671 trace_array_put(tr);
5677 trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
5679 struct trace_array *tr = iter->tr;
5681 /* Iterators are static, they should be filled or empty */
5682 if (trace_buffer_iter(iter, iter->cpu_file))
5683 return EPOLLIN | EPOLLRDNORM;
5685 if (tr->trace_flags & TRACE_ITER_BLOCK)
5687 * Always select as readable when in blocking mode
5689 return EPOLLIN | EPOLLRDNORM;
5691 return ring_buffer_poll_wait(iter->trace_buffer->buffer, iter->cpu_file,
5696 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
5698 struct trace_iterator *iter = filp->private_data;
5700 return trace_poll(iter, filp, poll_table);
5703 /* Must be called with iter->mutex held. */
5704 static int tracing_wait_pipe(struct file *filp)
5706 struct trace_iterator *iter = filp->private_data;
5709 while (trace_empty(iter)) {
5711 if ((filp->f_flags & O_NONBLOCK)) {
5716 * We block until we read something and tracing is disabled.
5717 * We still block if tracing is disabled, but we have never
5718 * read anything. This allows a user to cat this file, and
5719 * then enable tracing. But after we have read something,
5720 * we give an EOF when tracing is again disabled.
5722 * iter->pos will be 0 if we haven't read anything.
5724 if (!tracer_tracing_is_on(iter->tr) && iter->pos)
5727 mutex_unlock(&iter->mutex);
5729 ret = wait_on_pipe(iter, false);
5731 mutex_lock(&iter->mutex);
5744 tracing_read_pipe(struct file *filp, char __user *ubuf,
5745 size_t cnt, loff_t *ppos)
5747 struct trace_iterator *iter = filp->private_data;
5751 * Avoid more than one consumer on a single file descriptor
5752 * This is just a matter of traces coherency, the ring buffer itself
5755 mutex_lock(&iter->mutex);
5757 /* return any leftover data */
5758 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
5762 trace_seq_init(&iter->seq);
5764 if (iter->trace->read) {
5765 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
5771 sret = tracing_wait_pipe(filp);
5775 /* stop when tracing is finished */
5776 if (trace_empty(iter)) {
5781 if (cnt >= PAGE_SIZE)
5782 cnt = PAGE_SIZE - 1;
5784 /* reset all but tr, trace, and overruns */
5785 memset(&iter->seq, 0,
5786 sizeof(struct trace_iterator) -
5787 offsetof(struct trace_iterator, seq));
5788 cpumask_clear(iter->started);
5789 trace_seq_init(&iter->seq);
5792 trace_event_read_lock();
5793 trace_access_lock(iter->cpu_file);
5794 while (trace_find_next_entry_inc(iter) != NULL) {
5795 enum print_line_t ret;
5796 int save_len = iter->seq.seq.len;
5798 ret = print_trace_line(iter);
5799 if (ret == TRACE_TYPE_PARTIAL_LINE) {
5800 /* don't print partial lines */
5801 iter->seq.seq.len = save_len;
5804 if (ret != TRACE_TYPE_NO_CONSUME)
5805 trace_consume(iter);
5807 if (trace_seq_used(&iter->seq) >= cnt)
5811 * Setting the full flag means we reached the trace_seq buffer
5812 * size and we should leave by partial output condition above.
5813 * One of the trace_seq_* functions is not used properly.
5815 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
5818 trace_access_unlock(iter->cpu_file);
5819 trace_event_read_unlock();
5821 /* Now copy what we have to the user */
5822 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
5823 if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
5824 trace_seq_init(&iter->seq);
5827 * If there was nothing to send to user, in spite of consuming trace
5828 * entries, go back to wait for more entries.
5834 mutex_unlock(&iter->mutex);
5839 static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
5842 __free_page(spd->pages[idx]);
5845 static const struct pipe_buf_operations tracing_pipe_buf_ops = {
5847 .confirm = generic_pipe_buf_confirm,
5848 .release = generic_pipe_buf_release,
5849 .steal = generic_pipe_buf_steal,
5850 .get = generic_pipe_buf_get,
5854 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
5860 /* Seq buffer is page-sized, exactly what we need. */
5862 save_len = iter->seq.seq.len;
5863 ret = print_trace_line(iter);
5865 if (trace_seq_has_overflowed(&iter->seq)) {
5866 iter->seq.seq.len = save_len;
5871 * This should not be hit, because it should only
5872 * be set if the iter->seq overflowed. But check it
5873 * anyway to be safe.
5875 if (ret == TRACE_TYPE_PARTIAL_LINE) {
5876 iter->seq.seq.len = save_len;
5880 count = trace_seq_used(&iter->seq) - save_len;
5883 iter->seq.seq.len = save_len;
5887 if (ret != TRACE_TYPE_NO_CONSUME)
5888 trace_consume(iter);
5890 if (!trace_find_next_entry_inc(iter)) {
5900 static ssize_t tracing_splice_read_pipe(struct file *filp,
5902 struct pipe_inode_info *pipe,
5906 struct page *pages_def[PIPE_DEF_BUFFERS];
5907 struct partial_page partial_def[PIPE_DEF_BUFFERS];
5908 struct trace_iterator *iter = filp->private_data;
5909 struct splice_pipe_desc spd = {
5911 .partial = partial_def,
5912 .nr_pages = 0, /* This gets updated below. */
5913 .nr_pages_max = PIPE_DEF_BUFFERS,
5914 .ops = &tracing_pipe_buf_ops,
5915 .spd_release = tracing_spd_release_pipe,
5921 if (splice_grow_spd(pipe, &spd))
5924 mutex_lock(&iter->mutex);
5926 if (iter->trace->splice_read) {
5927 ret = iter->trace->splice_read(iter, filp,
5928 ppos, pipe, len, flags);
5933 ret = tracing_wait_pipe(filp);
5937 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
5942 trace_event_read_lock();
5943 trace_access_lock(iter->cpu_file);
5945 /* Fill as many pages as possible. */
5946 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
5947 spd.pages[i] = alloc_page(GFP_KERNEL);
5951 rem = tracing_fill_pipe_page(rem, iter);
5953 /* Copy the data into the page, so we can start over. */
5954 ret = trace_seq_to_buffer(&iter->seq,
5955 page_address(spd.pages[i]),
5956 trace_seq_used(&iter->seq));
5958 __free_page(spd.pages[i]);
5961 spd.partial[i].offset = 0;
5962 spd.partial[i].len = trace_seq_used(&iter->seq);
5964 trace_seq_init(&iter->seq);
5967 trace_access_unlock(iter->cpu_file);
5968 trace_event_read_unlock();
5969 mutex_unlock(&iter->mutex);
5974 ret = splice_to_pipe(pipe, &spd);
5978 splice_shrink_spd(&spd);
5982 mutex_unlock(&iter->mutex);
5987 tracing_entries_read(struct file *filp, char __user *ubuf,
5988 size_t cnt, loff_t *ppos)
5990 struct inode *inode = file_inode(filp);
5991 struct trace_array *tr = inode->i_private;
5992 int cpu = tracing_get_cpu(inode);
5997 mutex_lock(&trace_types_lock);
5999 if (cpu == RING_BUFFER_ALL_CPUS) {
6000 int cpu, buf_size_same;
6005 /* check if all cpu sizes are same */
6006 for_each_tracing_cpu(cpu) {
6007 /* fill in the size from first enabled cpu */
6009 size = per_cpu_ptr(tr->trace_buffer.data, cpu)->entries;
6010 if (size != per_cpu_ptr(tr->trace_buffer.data, cpu)->entries) {
6016 if (buf_size_same) {
6017 if (!ring_buffer_expanded)
6018 r = sprintf(buf, "%lu (expanded: %lu)\n",
6020 trace_buf_size >> 10);
6022 r = sprintf(buf, "%lu\n", size >> 10);
6024 r = sprintf(buf, "X\n");
6026 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
6028 mutex_unlock(&trace_types_lock);
6030 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6035 tracing_entries_write(struct file *filp, const char __user *ubuf,
6036 size_t cnt, loff_t *ppos)
6038 struct inode *inode = file_inode(filp);
6039 struct trace_array *tr = inode->i_private;
6043 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6047 /* must have at least 1 entry */
6051 /* value is in KB */
6053 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
6063 tracing_total_entries_read(struct file *filp, char __user *ubuf,
6064 size_t cnt, loff_t *ppos)
6066 struct trace_array *tr = filp->private_data;
6069 unsigned long size = 0, expanded_size = 0;
6071 mutex_lock(&trace_types_lock);
6072 for_each_tracing_cpu(cpu) {
6073 size += per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10;
6074 if (!ring_buffer_expanded)
6075 expanded_size += trace_buf_size >> 10;
6077 if (ring_buffer_expanded)
6078 r = sprintf(buf, "%lu\n", size);
6080 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
6081 mutex_unlock(&trace_types_lock);
6083 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6087 tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
6088 size_t cnt, loff_t *ppos)
6091 * There is no need to read what the user has written, this function
6092 * is just to make sure that there is no error when "echo" is used
6101 tracing_free_buffer_release(struct inode *inode, struct file *filp)
6103 struct trace_array *tr = inode->i_private;
6105 /* disable tracing ? */
6106 if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
6107 tracer_tracing_off(tr);
6108 /* resize the ring buffer to 0 */
6109 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
6111 trace_array_put(tr);
6117 tracing_mark_write(struct file *filp, const char __user *ubuf,
6118 size_t cnt, loff_t *fpos)
6120 struct trace_array *tr = filp->private_data;
6121 struct ring_buffer_event *event;
6122 enum event_trigger_type tt = ETT_NONE;
6123 struct ring_buffer *buffer;
6124 struct print_entry *entry;
6125 unsigned long irq_flags;
6126 const char faulted[] = "<faulted>";
6131 /* Used in tracing_mark_raw_write() as well */
6132 #define FAULTED_SIZE (sizeof(faulted) - 1) /* '\0' is already accounted for */
6134 if (tracing_disabled)
6137 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
6140 if (cnt > TRACE_BUF_SIZE)
6141 cnt = TRACE_BUF_SIZE;
6143 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
6145 local_save_flags(irq_flags);
6146 size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */
6148 /* If less than "<faulted>", then make sure we can still add that */
6149 if (cnt < FAULTED_SIZE)
6150 size += FAULTED_SIZE - cnt;
6152 buffer = tr->trace_buffer.buffer;
6153 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
6154 irq_flags, preempt_count());
6155 if (unlikely(!event))
6156 /* Ring buffer disabled, return as if not open for write */
6159 entry = ring_buffer_event_data(event);
6160 entry->ip = _THIS_IP_;
6162 len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
6164 memcpy(&entry->buf, faulted, FAULTED_SIZE);
6171 if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
6172 /* do not add \n before testing triggers, but add \0 */
6173 entry->buf[cnt] = '\0';
6174 tt = event_triggers_call(tr->trace_marker_file, entry, event);
6177 if (entry->buf[cnt - 1] != '\n') {
6178 entry->buf[cnt] = '\n';
6179 entry->buf[cnt + 1] = '\0';
6181 entry->buf[cnt] = '\0';
6183 __buffer_unlock_commit(buffer, event);
6186 event_triggers_post_call(tr->trace_marker_file, tt);
6194 /* Limit it for now to 3K (including tag) */
6195 #define RAW_DATA_MAX_SIZE (1024*3)
6198 tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
6199 size_t cnt, loff_t *fpos)
6201 struct trace_array *tr = filp->private_data;
6202 struct ring_buffer_event *event;
6203 struct ring_buffer *buffer;
6204 struct raw_data_entry *entry;
6205 const char faulted[] = "<faulted>";
6206 unsigned long irq_flags;
6211 #define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
6213 if (tracing_disabled)
6216 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
6219 /* The marker must at least have a tag id */
6220 if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE)
6223 if (cnt > TRACE_BUF_SIZE)
6224 cnt = TRACE_BUF_SIZE;
6226 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
6228 local_save_flags(irq_flags);
6229 size = sizeof(*entry) + cnt;
6230 if (cnt < FAULT_SIZE_ID)
6231 size += FAULT_SIZE_ID - cnt;
6233 buffer = tr->trace_buffer.buffer;
6234 event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
6235 irq_flags, preempt_count());
6237 /* Ring buffer disabled, return as if not open for write */
6240 entry = ring_buffer_event_data(event);
6242 len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
6245 memcpy(&entry->buf, faulted, FAULTED_SIZE);
6250 __buffer_unlock_commit(buffer, event);
6258 static int tracing_clock_show(struct seq_file *m, void *v)
6260 struct trace_array *tr = m->private;
6263 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
6265 "%s%s%s%s", i ? " " : "",
6266 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
6267 i == tr->clock_id ? "]" : "");
6273 int tracing_set_clock(struct trace_array *tr, const char *clockstr)
6277 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
6278 if (strcmp(trace_clocks[i].name, clockstr) == 0)
6281 if (i == ARRAY_SIZE(trace_clocks))
6284 mutex_lock(&trace_types_lock);
6288 ring_buffer_set_clock(tr->trace_buffer.buffer, trace_clocks[i].func);
6291 * New clock may not be consistent with the previous clock.
6292 * Reset the buffer so that it doesn't have incomparable timestamps.
6294 tracing_reset_online_cpus(&tr->trace_buffer);
6296 #ifdef CONFIG_TRACER_MAX_TRACE
6297 if (tr->max_buffer.buffer)
6298 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
6299 tracing_reset_online_cpus(&tr->max_buffer);
6302 mutex_unlock(&trace_types_lock);
6307 static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
6308 size_t cnt, loff_t *fpos)
6310 struct seq_file *m = filp->private_data;
6311 struct trace_array *tr = m->private;
6313 const char *clockstr;
6316 if (cnt >= sizeof(buf))
6319 if (copy_from_user(buf, ubuf, cnt))
6324 clockstr = strstrip(buf);
6326 ret = tracing_set_clock(tr, clockstr);
6335 static int tracing_clock_open(struct inode *inode, struct file *file)
6337 struct trace_array *tr = inode->i_private;
6340 if (tracing_disabled)
6343 if (trace_array_get(tr))
6346 ret = single_open(file, tracing_clock_show, inode->i_private);
6348 trace_array_put(tr);
6353 static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
6355 struct trace_array *tr = m->private;
6357 mutex_lock(&trace_types_lock);
6359 if (ring_buffer_time_stamp_abs(tr->trace_buffer.buffer))
6360 seq_puts(m, "delta [absolute]\n");
6362 seq_puts(m, "[delta] absolute\n");
6364 mutex_unlock(&trace_types_lock);
6369 static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
6371 struct trace_array *tr = inode->i_private;
6374 if (tracing_disabled)
6377 if (trace_array_get(tr))
6380 ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
6382 trace_array_put(tr);
6387 int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs)
6391 mutex_lock(&trace_types_lock);
6393 if (abs && tr->time_stamp_abs_ref++)
6397 if (WARN_ON_ONCE(!tr->time_stamp_abs_ref)) {
6402 if (--tr->time_stamp_abs_ref)
6406 ring_buffer_set_time_stamp_abs(tr->trace_buffer.buffer, abs);
6408 #ifdef CONFIG_TRACER_MAX_TRACE
6409 if (tr->max_buffer.buffer)
6410 ring_buffer_set_time_stamp_abs(tr->max_buffer.buffer, abs);
6413 mutex_unlock(&trace_types_lock);
6418 struct ftrace_buffer_info {
6419 struct trace_iterator iter;
6421 unsigned int spare_cpu;
6425 #ifdef CONFIG_TRACER_SNAPSHOT
6426 static int tracing_snapshot_open(struct inode *inode, struct file *file)
6428 struct trace_array *tr = inode->i_private;
6429 struct trace_iterator *iter;
6433 if (trace_array_get(tr) < 0)
6436 if (file->f_mode & FMODE_READ) {
6437 iter = __tracing_open(inode, file, true);
6439 ret = PTR_ERR(iter);
6441 /* Writes still need the seq_file to hold the private data */
6443 m = kzalloc(sizeof(*m), GFP_KERNEL);
6446 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
6454 iter->trace_buffer = &tr->max_buffer;
6455 iter->cpu_file = tracing_get_cpu(inode);
6457 file->private_data = m;
6461 trace_array_put(tr);
6467 tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
6470 struct seq_file *m = filp->private_data;
6471 struct trace_iterator *iter = m->private;
6472 struct trace_array *tr = iter->tr;
6476 ret = tracing_update_buffers();
6480 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6484 mutex_lock(&trace_types_lock);
6486 if (tr->current_trace->use_max_tr) {
6493 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
6497 if (tr->allocated_snapshot)
6501 /* Only allow per-cpu swap if the ring buffer supports it */
6502 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
6503 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
6508 if (tr->allocated_snapshot)
6509 ret = resize_buffer_duplicate_size(&tr->max_buffer,
6510 &tr->trace_buffer, iter->cpu_file);
6512 ret = tracing_alloc_snapshot_instance(tr);
6515 local_irq_disable();
6516 /* Now, we're going to swap */
6517 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
6518 update_max_tr(tr, current, smp_processor_id());
6520 update_max_tr_single(tr, current, iter->cpu_file);
6524 if (tr->allocated_snapshot) {
6525 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
6526 tracing_reset_online_cpus(&tr->max_buffer);
6528 tracing_reset(&tr->max_buffer, iter->cpu_file);
6538 mutex_unlock(&trace_types_lock);
6542 static int tracing_snapshot_release(struct inode *inode, struct file *file)
6544 struct seq_file *m = file->private_data;
6547 ret = tracing_release(inode, file);
6549 if (file->f_mode & FMODE_READ)
6552 /* If write only, the seq_file is just a stub */
6560 static int tracing_buffers_open(struct inode *inode, struct file *filp);
6561 static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
6562 size_t count, loff_t *ppos);
6563 static int tracing_buffers_release(struct inode *inode, struct file *file);
6564 static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
6565 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
6567 static int snapshot_raw_open(struct inode *inode, struct file *filp)
6569 struct ftrace_buffer_info *info;
6572 ret = tracing_buffers_open(inode, filp);
6576 info = filp->private_data;
6578 if (info->iter.trace->use_max_tr) {
6579 tracing_buffers_release(inode, filp);
6583 info->iter.snapshot = true;
6584 info->iter.trace_buffer = &info->iter.tr->max_buffer;
6589 #endif /* CONFIG_TRACER_SNAPSHOT */
6592 static const struct file_operations tracing_thresh_fops = {
6593 .open = tracing_open_generic,
6594 .read = tracing_thresh_read,
6595 .write = tracing_thresh_write,
6596 .llseek = generic_file_llseek,
6599 #if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
6600 static const struct file_operations tracing_max_lat_fops = {
6601 .open = tracing_open_generic,
6602 .read = tracing_max_lat_read,
6603 .write = tracing_max_lat_write,
6604 .llseek = generic_file_llseek,
6608 static const struct file_operations set_tracer_fops = {
6609 .open = tracing_open_generic,
6610 .read = tracing_set_trace_read,
6611 .write = tracing_set_trace_write,
6612 .llseek = generic_file_llseek,
6615 static const struct file_operations tracing_pipe_fops = {
6616 .open = tracing_open_pipe,
6617 .poll = tracing_poll_pipe,
6618 .read = tracing_read_pipe,
6619 .splice_read = tracing_splice_read_pipe,
6620 .release = tracing_release_pipe,
6621 .llseek = no_llseek,
6624 static const struct file_operations tracing_entries_fops = {
6625 .open = tracing_open_generic_tr,
6626 .read = tracing_entries_read,
6627 .write = tracing_entries_write,
6628 .llseek = generic_file_llseek,
6629 .release = tracing_release_generic_tr,
6632 static const struct file_operations tracing_total_entries_fops = {
6633 .open = tracing_open_generic_tr,
6634 .read = tracing_total_entries_read,
6635 .llseek = generic_file_llseek,
6636 .release = tracing_release_generic_tr,
6639 static const struct file_operations tracing_free_buffer_fops = {
6640 .open = tracing_open_generic_tr,
6641 .write = tracing_free_buffer_write,
6642 .release = tracing_free_buffer_release,
6645 static const struct file_operations tracing_mark_fops = {
6646 .open = tracing_open_generic_tr,
6647 .write = tracing_mark_write,
6648 .llseek = generic_file_llseek,
6649 .release = tracing_release_generic_tr,
6652 static const struct file_operations tracing_mark_raw_fops = {
6653 .open = tracing_open_generic_tr,
6654 .write = tracing_mark_raw_write,
6655 .llseek = generic_file_llseek,
6656 .release = tracing_release_generic_tr,
6659 static const struct file_operations trace_clock_fops = {
6660 .open = tracing_clock_open,
6662 .llseek = seq_lseek,
6663 .release = tracing_single_release_tr,
6664 .write = tracing_clock_write,
6667 static const struct file_operations trace_time_stamp_mode_fops = {
6668 .open = tracing_time_stamp_mode_open,
6670 .llseek = seq_lseek,
6671 .release = tracing_single_release_tr,
6674 #ifdef CONFIG_TRACER_SNAPSHOT
6675 static const struct file_operations snapshot_fops = {
6676 .open = tracing_snapshot_open,
6678 .write = tracing_snapshot_write,
6679 .llseek = tracing_lseek,
6680 .release = tracing_snapshot_release,
6683 static const struct file_operations snapshot_raw_fops = {
6684 .open = snapshot_raw_open,
6685 .read = tracing_buffers_read,
6686 .release = tracing_buffers_release,
6687 .splice_read = tracing_buffers_splice_read,
6688 .llseek = no_llseek,
6691 #endif /* CONFIG_TRACER_SNAPSHOT */
6693 static int tracing_buffers_open(struct inode *inode, struct file *filp)
6695 struct trace_array *tr = inode->i_private;
6696 struct ftrace_buffer_info *info;
6699 if (tracing_disabled)
6702 if (trace_array_get(tr) < 0)
6705 info = kzalloc(sizeof(*info), GFP_KERNEL);
6707 trace_array_put(tr);
6711 mutex_lock(&trace_types_lock);
6714 info->iter.cpu_file = tracing_get_cpu(inode);
6715 info->iter.trace = tr->current_trace;
6716 info->iter.trace_buffer = &tr->trace_buffer;
6718 /* Force reading ring buffer for first read */
6719 info->read = (unsigned int)-1;
6721 filp->private_data = info;
6723 tr->current_trace->ref++;
6725 mutex_unlock(&trace_types_lock);
6727 ret = nonseekable_open(inode, filp);
6729 trace_array_put(tr);
6735 tracing_buffers_poll(struct file *filp, poll_table *poll_table)
6737 struct ftrace_buffer_info *info = filp->private_data;
6738 struct trace_iterator *iter = &info->iter;
6740 return trace_poll(iter, filp, poll_table);
6744 tracing_buffers_read(struct file *filp, char __user *ubuf,
6745 size_t count, loff_t *ppos)
6747 struct ftrace_buffer_info *info = filp->private_data;
6748 struct trace_iterator *iter = &info->iter;
6755 #ifdef CONFIG_TRACER_MAX_TRACE
6756 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
6761 info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
6763 if (IS_ERR(info->spare)) {
6764 ret = PTR_ERR(info->spare);
6767 info->spare_cpu = iter->cpu_file;
6773 /* Do we have previous read data to read? */
6774 if (info->read < PAGE_SIZE)
6778 trace_access_lock(iter->cpu_file);
6779 ret = ring_buffer_read_page(iter->trace_buffer->buffer,
6783 trace_access_unlock(iter->cpu_file);
6786 if (trace_empty(iter)) {
6787 if ((filp->f_flags & O_NONBLOCK))
6790 ret = wait_on_pipe(iter, false);
6801 size = PAGE_SIZE - info->read;
6805 ret = copy_to_user(ubuf, info->spare + info->read, size);
6817 static int tracing_buffers_release(struct inode *inode, struct file *file)
6819 struct ftrace_buffer_info *info = file->private_data;
6820 struct trace_iterator *iter = &info->iter;
6822 mutex_lock(&trace_types_lock);
6824 iter->tr->current_trace->ref--;
6826 __trace_array_put(iter->tr);
6829 ring_buffer_free_read_page(iter->trace_buffer->buffer,
6830 info->spare_cpu, info->spare);
6833 mutex_unlock(&trace_types_lock);
6839 struct ring_buffer *buffer;
6842 refcount_t refcount;
6845 static void buffer_ref_release(struct buffer_ref *ref)
6847 if (!refcount_dec_and_test(&ref->refcount))
6849 ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
6853 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
6854 struct pipe_buffer *buf)
6856 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
6858 buffer_ref_release(ref);
6862 static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
6863 struct pipe_buffer *buf)
6865 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
6867 if (refcount_read(&ref->refcount) > INT_MAX/2)
6870 refcount_inc(&ref->refcount);
6874 /* Pipe buffer operations for a buffer. */
6875 static const struct pipe_buf_operations buffer_pipe_buf_ops = {
6877 .confirm = generic_pipe_buf_confirm,
6878 .release = buffer_pipe_buf_release,
6879 .steal = generic_pipe_buf_nosteal,
6880 .get = buffer_pipe_buf_get,
6884 * Callback from splice_to_pipe(), if we need to release some pages
6885 * at the end of the spd in case we error'ed out in filling the pipe.
6887 static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
6889 struct buffer_ref *ref =
6890 (struct buffer_ref *)spd->partial[i].private;
6892 buffer_ref_release(ref);
6893 spd->partial[i].private = 0;
6897 tracing_buffers_splice_read(struct file *file, loff_t *ppos,
6898 struct pipe_inode_info *pipe, size_t len,
6901 struct ftrace_buffer_info *info = file->private_data;
6902 struct trace_iterator *iter = &info->iter;
6903 struct partial_page partial_def[PIPE_DEF_BUFFERS];
6904 struct page *pages_def[PIPE_DEF_BUFFERS];
6905 struct splice_pipe_desc spd = {
6907 .partial = partial_def,
6908 .nr_pages_max = PIPE_DEF_BUFFERS,
6909 .ops = &buffer_pipe_buf_ops,
6910 .spd_release = buffer_spd_release,
6912 struct buffer_ref *ref;
6916 #ifdef CONFIG_TRACER_MAX_TRACE
6917 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
6921 if (*ppos & (PAGE_SIZE - 1))
6924 if (len & (PAGE_SIZE - 1)) {
6925 if (len < PAGE_SIZE)
6930 if (splice_grow_spd(pipe, &spd))
6934 trace_access_lock(iter->cpu_file);
6935 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
6937 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
6941 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
6947 refcount_set(&ref->refcount, 1);
6948 ref->buffer = iter->trace_buffer->buffer;
6949 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
6950 if (IS_ERR(ref->page)) {
6951 ret = PTR_ERR(ref->page);
6956 ref->cpu = iter->cpu_file;
6958 r = ring_buffer_read_page(ref->buffer, &ref->page,
6959 len, iter->cpu_file, 1);
6961 ring_buffer_free_read_page(ref->buffer, ref->cpu,
6967 page = virt_to_page(ref->page);
6969 spd.pages[i] = page;
6970 spd.partial[i].len = PAGE_SIZE;
6971 spd.partial[i].offset = 0;
6972 spd.partial[i].private = (unsigned long)ref;
6976 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
6979 trace_access_unlock(iter->cpu_file);
6982 /* did we read anything? */
6983 if (!spd.nr_pages) {
6988 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
6991 ret = wait_on_pipe(iter, true);
6998 ret = splice_to_pipe(pipe, &spd);
7000 splice_shrink_spd(&spd);
7005 static const struct file_operations tracing_buffers_fops = {
7006 .open = tracing_buffers_open,
7007 .read = tracing_buffers_read,
7008 .poll = tracing_buffers_poll,
7009 .release = tracing_buffers_release,
7010 .splice_read = tracing_buffers_splice_read,
7011 .llseek = no_llseek,
7015 tracing_stats_read(struct file *filp, char __user *ubuf,
7016 size_t count, loff_t *ppos)
7018 struct inode *inode = file_inode(filp);
7019 struct trace_array *tr = inode->i_private;
7020 struct trace_buffer *trace_buf = &tr->trace_buffer;
7021 int cpu = tracing_get_cpu(inode);
7022 struct trace_seq *s;
7024 unsigned long long t;
7025 unsigned long usec_rem;
7027 s = kmalloc(sizeof(*s), GFP_KERNEL);
7033 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
7034 trace_seq_printf(s, "entries: %ld\n", cnt);
7036 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
7037 trace_seq_printf(s, "overrun: %ld\n", cnt);
7039 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
7040 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
7042 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
7043 trace_seq_printf(s, "bytes: %ld\n", cnt);
7045 if (trace_clocks[tr->clock_id].in_ns) {
7046 /* local or global for trace_clock */
7047 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
7048 usec_rem = do_div(t, USEC_PER_SEC);
7049 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
7052 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer, cpu));
7053 usec_rem = do_div(t, USEC_PER_SEC);
7054 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
7056 /* counter or tsc mode for trace_clock */
7057 trace_seq_printf(s, "oldest event ts: %llu\n",
7058 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
7060 trace_seq_printf(s, "now ts: %llu\n",
7061 ring_buffer_time_stamp(trace_buf->buffer, cpu));
7064 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
7065 trace_seq_printf(s, "dropped events: %ld\n", cnt);
7067 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
7068 trace_seq_printf(s, "read events: %ld\n", cnt);
7070 count = simple_read_from_buffer(ubuf, count, ppos,
7071 s->buffer, trace_seq_used(s));
7078 static const struct file_operations tracing_stats_fops = {
7079 .open = tracing_open_generic_tr,
7080 .read = tracing_stats_read,
7081 .llseek = generic_file_llseek,
7082 .release = tracing_release_generic_tr,
7085 #ifdef CONFIG_DYNAMIC_FTRACE
7088 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
7089 size_t cnt, loff_t *ppos)
7091 unsigned long *p = filp->private_data;
7092 char buf[64]; /* Not too big for a shallow stack */
7095 r = scnprintf(buf, 63, "%ld", *p);
7098 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
7101 static const struct file_operations tracing_dyn_info_fops = {
7102 .open = tracing_open_generic,
7103 .read = tracing_read_dyn_info,
7104 .llseek = generic_file_llseek,
7106 #endif /* CONFIG_DYNAMIC_FTRACE */
7108 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
7110 ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
7111 struct trace_array *tr, struct ftrace_probe_ops *ops,
7114 tracing_snapshot_instance(tr);
7118 ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
7119 struct trace_array *tr, struct ftrace_probe_ops *ops,
7122 struct ftrace_func_mapper *mapper = data;
7126 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
7136 tracing_snapshot_instance(tr);
7140 ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
7141 struct ftrace_probe_ops *ops, void *data)
7143 struct ftrace_func_mapper *mapper = data;
7146 seq_printf(m, "%ps:", (void *)ip);
7148 seq_puts(m, "snapshot");
7151 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
7154 seq_printf(m, ":count=%ld\n", *count);
7156 seq_puts(m, ":unlimited\n");
7162 ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
7163 unsigned long ip, void *init_data, void **data)
7165 struct ftrace_func_mapper *mapper = *data;
7168 mapper = allocate_ftrace_func_mapper();
7174 return ftrace_func_mapper_add_ip(mapper, ip, init_data);
7178 ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
7179 unsigned long ip, void *data)
7181 struct ftrace_func_mapper *mapper = data;
7186 free_ftrace_func_mapper(mapper, NULL);
7190 ftrace_func_mapper_remove_ip(mapper, ip);
7193 static struct ftrace_probe_ops snapshot_probe_ops = {
7194 .func = ftrace_snapshot,
7195 .print = ftrace_snapshot_print,
7198 static struct ftrace_probe_ops snapshot_count_probe_ops = {
7199 .func = ftrace_count_snapshot,
7200 .print = ftrace_snapshot_print,
7201 .init = ftrace_snapshot_init,
7202 .free = ftrace_snapshot_free,
7206 ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
7207 char *glob, char *cmd, char *param, int enable)
7209 struct ftrace_probe_ops *ops;
7210 void *count = (void *)-1;
7217 /* hash funcs only work with set_ftrace_filter */
7221 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
7224 return unregister_ftrace_function_probe_func(glob+1, tr, ops);
7229 number = strsep(¶m, ":");
7231 if (!strlen(number))
7235 * We use the callback data field (which is a pointer)
7238 ret = kstrtoul(number, 0, (unsigned long *)&count);
7243 ret = tracing_alloc_snapshot_instance(tr);
7247 ret = register_ftrace_function_probe(glob, tr, ops, count);
7250 return ret < 0 ? ret : 0;
7253 static struct ftrace_func_command ftrace_snapshot_cmd = {
7255 .func = ftrace_trace_snapshot_callback,
7258 static __init int register_snapshot_cmd(void)
7260 return register_ftrace_command(&ftrace_snapshot_cmd);
7263 static inline __init int register_snapshot_cmd(void) { return 0; }
7264 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
7266 static struct dentry *tracing_get_dentry(struct trace_array *tr)
7268 if (WARN_ON(!tr->dir))
7269 return ERR_PTR(-ENODEV);
7271 /* Top directory uses NULL as the parent */
7272 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
7275 /* All sub buffers have a descriptor */
7279 static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
7281 struct dentry *d_tracer;
7284 return tr->percpu_dir;
7286 d_tracer = tracing_get_dentry(tr);
7287 if (IS_ERR(d_tracer))
7290 tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
7292 WARN_ONCE(!tr->percpu_dir,
7293 "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
7295 return tr->percpu_dir;
7298 static struct dentry *
7299 trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
7300 void *data, long cpu, const struct file_operations *fops)
7302 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
7304 if (ret) /* See tracing_get_cpu() */
7305 d_inode(ret)->i_cdev = (void *)(cpu + 1);
7310 tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
7312 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
7313 struct dentry *d_cpu;
7314 char cpu_dir[30]; /* 30 characters should be more than enough */
7319 snprintf(cpu_dir, 30, "cpu%ld", cpu);
7320 d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
7322 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
7326 /* per cpu trace_pipe */
7327 trace_create_cpu_file("trace_pipe", 0444, d_cpu,
7328 tr, cpu, &tracing_pipe_fops);
7331 trace_create_cpu_file("trace", 0644, d_cpu,
7332 tr, cpu, &tracing_fops);
7334 trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
7335 tr, cpu, &tracing_buffers_fops);
7337 trace_create_cpu_file("stats", 0444, d_cpu,
7338 tr, cpu, &tracing_stats_fops);
7340 trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
7341 tr, cpu, &tracing_entries_fops);
7343 #ifdef CONFIG_TRACER_SNAPSHOT
7344 trace_create_cpu_file("snapshot", 0644, d_cpu,
7345 tr, cpu, &snapshot_fops);
7347 trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
7348 tr, cpu, &snapshot_raw_fops);
7352 #ifdef CONFIG_FTRACE_SELFTEST
7353 /* Let selftest have access to static functions in this file */
7354 #include "trace_selftest.c"
7358 trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
7361 struct trace_option_dentry *topt = filp->private_data;
7364 if (topt->flags->val & topt->opt->bit)
7369 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
7373 trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
7376 struct trace_option_dentry *topt = filp->private_data;
7380 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7384 if (val != 0 && val != 1)
7387 if (!!(topt->flags->val & topt->opt->bit) != val) {
7388 mutex_lock(&trace_types_lock);
7389 ret = __set_tracer_option(topt->tr, topt->flags,
7391 mutex_unlock(&trace_types_lock);
7402 static const struct file_operations trace_options_fops = {
7403 .open = tracing_open_generic,
7404 .read = trace_options_read,
7405 .write = trace_options_write,
7406 .llseek = generic_file_llseek,
7410 * In order to pass in both the trace_array descriptor as well as the index
7411 * to the flag that the trace option file represents, the trace_array
7412 * has a character array of trace_flags_index[], which holds the index
7413 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
7414 * The address of this character array is passed to the flag option file
7415 * read/write callbacks.
7417 * In order to extract both the index and the trace_array descriptor,
7418 * get_tr_index() uses the following algorithm.
7422 * As the pointer itself contains the address of the index (remember
7425 * Then to get the trace_array descriptor, by subtracting that index
7426 * from the ptr, we get to the start of the index itself.
7428 * ptr - idx == &index[0]
7430 * Then a simple container_of() from that pointer gets us to the
7431 * trace_array descriptor.
7433 static void get_tr_index(void *data, struct trace_array **ptr,
7434 unsigned int *pindex)
7436 *pindex = *(unsigned char *)data;
7438 *ptr = container_of(data - *pindex, struct trace_array,
7443 trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
7446 void *tr_index = filp->private_data;
7447 struct trace_array *tr;
7451 get_tr_index(tr_index, &tr, &index);
7453 if (tr->trace_flags & (1 << index))
7458 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
7462 trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
7465 void *tr_index = filp->private_data;
7466 struct trace_array *tr;
7471 get_tr_index(tr_index, &tr, &index);
7473 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7477 if (val != 0 && val != 1)
7480 mutex_lock(&event_mutex);
7481 mutex_lock(&trace_types_lock);
7482 ret = set_tracer_flag(tr, 1 << index, val);
7483 mutex_unlock(&trace_types_lock);
7484 mutex_unlock(&event_mutex);
7494 static const struct file_operations trace_options_core_fops = {
7495 .open = tracing_open_generic,
7496 .read = trace_options_core_read,
7497 .write = trace_options_core_write,
7498 .llseek = generic_file_llseek,
7501 struct dentry *trace_create_file(const char *name,
7503 struct dentry *parent,
7505 const struct file_operations *fops)
7509 ret = tracefs_create_file(name, mode, parent, data, fops);
7511 pr_warn("Could not create tracefs '%s' entry\n", name);
7517 static struct dentry *trace_options_init_dentry(struct trace_array *tr)
7519 struct dentry *d_tracer;
7524 d_tracer = tracing_get_dentry(tr);
7525 if (IS_ERR(d_tracer))
7528 tr->options = tracefs_create_dir("options", d_tracer);
7530 pr_warn("Could not create tracefs directory 'options'\n");
7538 create_trace_option_file(struct trace_array *tr,
7539 struct trace_option_dentry *topt,
7540 struct tracer_flags *flags,
7541 struct tracer_opt *opt)
7543 struct dentry *t_options;
7545 t_options = trace_options_init_dentry(tr);
7549 topt->flags = flags;
7553 topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
7554 &trace_options_fops);
7559 create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
7561 struct trace_option_dentry *topts;
7562 struct trace_options *tr_topts;
7563 struct tracer_flags *flags;
7564 struct tracer_opt *opts;
7571 flags = tracer->flags;
7573 if (!flags || !flags->opts)
7577 * If this is an instance, only create flags for tracers
7578 * the instance may have.
7580 if (!trace_ok_for_array(tracer, tr))
7583 for (i = 0; i < tr->nr_topts; i++) {
7584 /* Make sure there's no duplicate flags. */
7585 if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
7591 for (cnt = 0; opts[cnt].name; cnt++)
7594 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
7598 tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
7605 tr->topts = tr_topts;
7606 tr->topts[tr->nr_topts].tracer = tracer;
7607 tr->topts[tr->nr_topts].topts = topts;
7610 for (cnt = 0; opts[cnt].name; cnt++) {
7611 create_trace_option_file(tr, &topts[cnt], flags,
7613 WARN_ONCE(topts[cnt].entry == NULL,
7614 "Failed to create trace option: %s",
7619 static struct dentry *
7620 create_trace_option_core_file(struct trace_array *tr,
7621 const char *option, long index)
7623 struct dentry *t_options;
7625 t_options = trace_options_init_dentry(tr);
7629 return trace_create_file(option, 0644, t_options,
7630 (void *)&tr->trace_flags_index[index],
7631 &trace_options_core_fops);
7634 static void create_trace_options_dir(struct trace_array *tr)
7636 struct dentry *t_options;
7637 bool top_level = tr == &global_trace;
7640 t_options = trace_options_init_dentry(tr);
7644 for (i = 0; trace_options[i]; i++) {
7646 !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
7647 create_trace_option_core_file(tr, trace_options[i], i);
7652 rb_simple_read(struct file *filp, char __user *ubuf,
7653 size_t cnt, loff_t *ppos)
7655 struct trace_array *tr = filp->private_data;
7659 r = tracer_tracing_is_on(tr);
7660 r = sprintf(buf, "%d\n", r);
7662 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
7666 rb_simple_write(struct file *filp, const char __user *ubuf,
7667 size_t cnt, loff_t *ppos)
7669 struct trace_array *tr = filp->private_data;
7670 struct ring_buffer *buffer = tr->trace_buffer.buffer;
7674 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7679 mutex_lock(&trace_types_lock);
7680 if (!!val == tracer_tracing_is_on(tr)) {
7681 val = 0; /* do nothing */
7683 tracer_tracing_on(tr);
7684 if (tr->current_trace->start)
7685 tr->current_trace->start(tr);
7687 tracer_tracing_off(tr);
7688 if (tr->current_trace->stop)
7689 tr->current_trace->stop(tr);
7691 mutex_unlock(&trace_types_lock);
7699 static const struct file_operations rb_simple_fops = {
7700 .open = tracing_open_generic_tr,
7701 .read = rb_simple_read,
7702 .write = rb_simple_write,
7703 .release = tracing_release_generic_tr,
7704 .llseek = default_llseek,
7707 struct dentry *trace_instance_dir;
7710 init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
7713 allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
7715 enum ring_buffer_flags rb_flags;
7717 rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
7721 buf->buffer = ring_buffer_alloc(size, rb_flags);
7725 buf->data = alloc_percpu(struct trace_array_cpu);
7727 ring_buffer_free(buf->buffer);
7732 /* Allocate the first page for all buffers */
7733 set_buffer_entries(&tr->trace_buffer,
7734 ring_buffer_size(tr->trace_buffer.buffer, 0));
7739 static int allocate_trace_buffers(struct trace_array *tr, int size)
7743 ret = allocate_trace_buffer(tr, &tr->trace_buffer, size);
7747 #ifdef CONFIG_TRACER_MAX_TRACE
7748 ret = allocate_trace_buffer(tr, &tr->max_buffer,
7749 allocate_snapshot ? size : 1);
7751 ring_buffer_free(tr->trace_buffer.buffer);
7752 tr->trace_buffer.buffer = NULL;
7753 free_percpu(tr->trace_buffer.data);
7754 tr->trace_buffer.data = NULL;
7757 tr->allocated_snapshot = allocate_snapshot;
7760 * Only the top level trace array gets its snapshot allocated
7761 * from the kernel command line.
7763 allocate_snapshot = false;
7767 * Because of some magic with the way alloc_percpu() works on
7768 * x86_64, we need to synchronize the pgd of all the tables,
7769 * otherwise the trace events that happen in x86_64 page fault
7770 * handlers can't cope with accessing the chance that a
7771 * alloc_percpu()'d memory might be touched in the page fault trace
7772 * event. Oh, and we need to audit all other alloc_percpu() and vmalloc()
7773 * calls in tracing, because something might get triggered within a
7774 * page fault trace event!
7776 vmalloc_sync_mappings();
7781 static void free_trace_buffer(struct trace_buffer *buf)
7784 ring_buffer_free(buf->buffer);
7786 free_percpu(buf->data);
7791 static void free_trace_buffers(struct trace_array *tr)
7796 free_trace_buffer(&tr->trace_buffer);
7798 #ifdef CONFIG_TRACER_MAX_TRACE
7799 free_trace_buffer(&tr->max_buffer);
7803 static void init_trace_flags_index(struct trace_array *tr)
7807 /* Used by the trace options files */
7808 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
7809 tr->trace_flags_index[i] = i;
7812 static void __update_tracer_options(struct trace_array *tr)
7816 for (t = trace_types; t; t = t->next)
7817 add_tracer_options(tr, t);
7820 static void update_tracer_options(struct trace_array *tr)
7822 mutex_lock(&trace_types_lock);
7823 __update_tracer_options(tr);
7824 mutex_unlock(&trace_types_lock);
7827 static int instance_mkdir(const char *name)
7829 struct trace_array *tr;
7832 mutex_lock(&event_mutex);
7833 mutex_lock(&trace_types_lock);
7836 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7837 if (tr->name && strcmp(tr->name, name) == 0)
7842 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
7846 tr->name = kstrdup(name, GFP_KERNEL);
7850 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
7853 tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
7855 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
7857 raw_spin_lock_init(&tr->start_lock);
7859 tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
7861 tr->current_trace = &nop_trace;
7863 INIT_LIST_HEAD(&tr->systems);
7864 INIT_LIST_HEAD(&tr->events);
7865 INIT_LIST_HEAD(&tr->hist_vars);
7867 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
7870 tr->dir = tracefs_create_dir(name, trace_instance_dir);
7874 ret = event_trace_add_tracer(tr->dir, tr);
7876 tracefs_remove_recursive(tr->dir);
7880 ftrace_init_trace_array(tr);
7882 init_tracer_tracefs(tr, tr->dir);
7883 init_trace_flags_index(tr);
7884 __update_tracer_options(tr);
7886 list_add(&tr->list, &ftrace_trace_arrays);
7888 mutex_unlock(&trace_types_lock);
7889 mutex_unlock(&event_mutex);
7894 free_trace_buffers(tr);
7895 free_cpumask_var(tr->tracing_cpumask);
7900 mutex_unlock(&trace_types_lock);
7901 mutex_unlock(&event_mutex);
7907 static int instance_rmdir(const char *name)
7909 struct trace_array *tr;
7914 mutex_lock(&event_mutex);
7915 mutex_lock(&trace_types_lock);
7918 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7919 if (tr->name && strcmp(tr->name, name) == 0) {
7928 if (tr->ref || (tr->current_trace && tr->current_trace->ref))
7931 list_del(&tr->list);
7933 /* Disable all the flags that were enabled coming in */
7934 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
7935 if ((1 << i) & ZEROED_TRACE_FLAGS)
7936 set_tracer_flag(tr, 1 << i, 0);
7939 tracing_set_nop(tr);
7940 clear_ftrace_function_probes(tr);
7941 event_trace_del_tracer(tr);
7942 ftrace_clear_pids(tr);
7943 ftrace_destroy_function_files(tr);
7944 tracefs_remove_recursive(tr->dir);
7945 free_trace_buffers(tr);
7947 for (i = 0; i < tr->nr_topts; i++) {
7948 kfree(tr->topts[i].topts);
7952 free_cpumask_var(tr->tracing_cpumask);
7959 mutex_unlock(&trace_types_lock);
7960 mutex_unlock(&event_mutex);
7965 static __init void create_trace_instances(struct dentry *d_tracer)
7967 trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
7970 if (WARN_ON(!trace_instance_dir))
7975 init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7977 struct trace_event_file *file;
7980 trace_create_file("available_tracers", 0444, d_tracer,
7981 tr, &show_traces_fops);
7983 trace_create_file("current_tracer", 0644, d_tracer,
7984 tr, &set_tracer_fops);
7986 trace_create_file("tracing_cpumask", 0644, d_tracer,
7987 tr, &tracing_cpumask_fops);
7989 trace_create_file("trace_options", 0644, d_tracer,
7990 tr, &tracing_iter_fops);
7992 trace_create_file("trace", 0644, d_tracer,
7995 trace_create_file("trace_pipe", 0444, d_tracer,
7996 tr, &tracing_pipe_fops);
7998 trace_create_file("buffer_size_kb", 0644, d_tracer,
7999 tr, &tracing_entries_fops);
8001 trace_create_file("buffer_total_size_kb", 0444, d_tracer,
8002 tr, &tracing_total_entries_fops);
8004 trace_create_file("free_buffer", 0200, d_tracer,
8005 tr, &tracing_free_buffer_fops);
8007 trace_create_file("trace_marker", 0220, d_tracer,
8008 tr, &tracing_mark_fops);
8010 file = __find_event_file(tr, "ftrace", "print");
8011 if (file && file->dir)
8012 trace_create_file("trigger", 0644, file->dir, file,
8013 &event_trigger_fops);
8014 tr->trace_marker_file = file;
8016 trace_create_file("trace_marker_raw", 0220, d_tracer,
8017 tr, &tracing_mark_raw_fops);
8019 trace_create_file("trace_clock", 0644, d_tracer, tr,
8022 trace_create_file("tracing_on", 0644, d_tracer,
8023 tr, &rb_simple_fops);
8025 trace_create_file("timestamp_mode", 0444, d_tracer, tr,
8026 &trace_time_stamp_mode_fops);
8028 create_trace_options_dir(tr);
8030 #if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
8031 trace_create_file("tracing_max_latency", 0644, d_tracer,
8032 &tr->max_latency, &tracing_max_lat_fops);
8035 if (ftrace_create_function_files(tr, d_tracer))
8036 WARN(1, "Could not allocate function filter files");
8038 #ifdef CONFIG_TRACER_SNAPSHOT
8039 trace_create_file("snapshot", 0644, d_tracer,
8040 tr, &snapshot_fops);
8043 for_each_tracing_cpu(cpu)
8044 tracing_init_tracefs_percpu(tr, cpu);
8046 ftrace_init_tracefs(tr, d_tracer);
8049 static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
8051 struct vfsmount *mnt;
8052 struct file_system_type *type;
8055 * To maintain backward compatibility for tools that mount
8056 * debugfs to get to the tracing facility, tracefs is automatically
8057 * mounted to the debugfs/tracing directory.
8059 type = get_fs_type("tracefs");
8062 mnt = vfs_submount(mntpt, type, "tracefs", NULL);
8063 put_filesystem(type);
8072 * tracing_init_dentry - initialize top level trace array
8074 * This is called when creating files or directories in the tracing
8075 * directory. It is called via fs_initcall() by any of the boot up code
8076 * and expects to return the dentry of the top level tracing directory.
8078 struct dentry *tracing_init_dentry(void)
8080 struct trace_array *tr = &global_trace;
8082 /* The top level trace array uses NULL as parent */
8086 if (WARN_ON(!tracefs_initialized()) ||
8087 (IS_ENABLED(CONFIG_DEBUG_FS) &&
8088 WARN_ON(!debugfs_initialized())))
8089 return ERR_PTR(-ENODEV);
8092 * As there may still be users that expect the tracing
8093 * files to exist in debugfs/tracing, we must automount
8094 * the tracefs file system there, so older tools still
8095 * work with the newer kerenl.
8097 tr->dir = debugfs_create_automount("tracing", NULL,
8098 trace_automount, NULL);
8100 pr_warn_once("Could not create debugfs directory 'tracing'\n");
8101 return ERR_PTR(-ENOMEM);
8107 extern struct trace_eval_map *__start_ftrace_eval_maps[];
8108 extern struct trace_eval_map *__stop_ftrace_eval_maps[];
8110 static void __init trace_eval_init(void)
8114 len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
8115 trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
8118 #ifdef CONFIG_MODULES
8119 static void trace_module_add_evals(struct module *mod)
8121 if (!mod->num_trace_evals)
8125 * Modules with bad taint do not have events created, do
8126 * not bother with enums either.
8128 if (trace_module_has_bad_taint(mod))
8131 trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
8134 #ifdef CONFIG_TRACE_EVAL_MAP_FILE
8135 static void trace_module_remove_evals(struct module *mod)
8137 union trace_eval_map_item *map;
8138 union trace_eval_map_item **last = &trace_eval_maps;
8140 if (!mod->num_trace_evals)
8143 mutex_lock(&trace_eval_mutex);
8145 map = trace_eval_maps;
8148 if (map->head.mod == mod)
8150 map = trace_eval_jmp_to_tail(map);
8151 last = &map->tail.next;
8152 map = map->tail.next;
8157 *last = trace_eval_jmp_to_tail(map)->tail.next;
8160 mutex_unlock(&trace_eval_mutex);
8163 static inline void trace_module_remove_evals(struct module *mod) { }
8164 #endif /* CONFIG_TRACE_EVAL_MAP_FILE */
8166 static int trace_module_notify(struct notifier_block *self,
8167 unsigned long val, void *data)
8169 struct module *mod = data;
8172 case MODULE_STATE_COMING:
8173 trace_module_add_evals(mod);
8175 case MODULE_STATE_GOING:
8176 trace_module_remove_evals(mod);
8183 static struct notifier_block trace_module_nb = {
8184 .notifier_call = trace_module_notify,
8187 #endif /* CONFIG_MODULES */
8189 static __init int tracer_init_tracefs(void)
8191 struct dentry *d_tracer;
8193 trace_access_lock_init();
8195 d_tracer = tracing_init_dentry();
8196 if (IS_ERR(d_tracer))
8201 init_tracer_tracefs(&global_trace, d_tracer);
8202 ftrace_init_tracefs_toplevel(&global_trace, d_tracer);
8204 trace_create_file("tracing_thresh", 0644, d_tracer,
8205 &global_trace, &tracing_thresh_fops);
8207 trace_create_file("README", 0444, d_tracer,
8208 NULL, &tracing_readme_fops);
8210 trace_create_file("saved_cmdlines", 0444, d_tracer,
8211 NULL, &tracing_saved_cmdlines_fops);
8213 trace_create_file("saved_cmdlines_size", 0644, d_tracer,
8214 NULL, &tracing_saved_cmdlines_size_fops);
8216 trace_create_file("saved_tgids", 0444, d_tracer,
8217 NULL, &tracing_saved_tgids_fops);
8221 trace_create_eval_file(d_tracer);
8223 #ifdef CONFIG_MODULES
8224 register_module_notifier(&trace_module_nb);
8227 #ifdef CONFIG_DYNAMIC_FTRACE
8228 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
8229 &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
8232 create_trace_instances(d_tracer);
8234 update_tracer_options(&global_trace);
8239 static int trace_panic_handler(struct notifier_block *this,
8240 unsigned long event, void *unused)
8242 if (ftrace_dump_on_oops)
8243 ftrace_dump(ftrace_dump_on_oops);
8247 static struct notifier_block trace_panic_notifier = {
8248 .notifier_call = trace_panic_handler,
8250 .priority = 150 /* priority: INT_MAX >= x >= 0 */
8253 static int trace_die_handler(struct notifier_block *self,
8259 if (ftrace_dump_on_oops)
8260 ftrace_dump(ftrace_dump_on_oops);
8268 static struct notifier_block trace_die_notifier = {
8269 .notifier_call = trace_die_handler,
8274 * printk is set to max of 1024, we really don't need it that big.
8275 * Nothing should be printing 1000 characters anyway.
8277 #define TRACE_MAX_PRINT 1000
8280 * Define here KERN_TRACE so that we have one place to modify
8281 * it if we decide to change what log level the ftrace dump
8284 #define KERN_TRACE KERN_EMERG
8287 trace_printk_seq(struct trace_seq *s)
8289 /* Probably should print a warning here. */
8290 if (s->seq.len >= TRACE_MAX_PRINT)
8291 s->seq.len = TRACE_MAX_PRINT;
8294 * More paranoid code. Although the buffer size is set to
8295 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
8296 * an extra layer of protection.
8298 if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
8299 s->seq.len = s->seq.size - 1;
8301 /* should be zero ended, but we are paranoid. */
8302 s->buffer[s->seq.len] = 0;
8304 printk(KERN_TRACE "%s", s->buffer);
8309 void trace_init_global_iter(struct trace_iterator *iter)
8311 iter->tr = &global_trace;
8312 iter->trace = iter->tr->current_trace;
8313 iter->cpu_file = RING_BUFFER_ALL_CPUS;
8314 iter->trace_buffer = &global_trace.trace_buffer;
8316 if (iter->trace && iter->trace->open)
8317 iter->trace->open(iter);
8319 /* Annotate start of buffers if we had overruns */
8320 if (ring_buffer_overruns(iter->trace_buffer->buffer))
8321 iter->iter_flags |= TRACE_FILE_ANNOTATE;
8323 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
8324 if (trace_clocks[iter->tr->clock_id].in_ns)
8325 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
8328 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
8330 /* use static because iter can be a bit big for the stack */
8331 static struct trace_iterator iter;
8332 static atomic_t dump_running;
8333 struct trace_array *tr = &global_trace;
8334 unsigned int old_userobj;
8335 unsigned long flags;
8338 /* Only allow one dump user at a time. */
8339 if (atomic_inc_return(&dump_running) != 1) {
8340 atomic_dec(&dump_running);
8345 * Always turn off tracing when we dump.
8346 * We don't need to show trace output of what happens
8347 * between multiple crashes.
8349 * If the user does a sysrq-z, then they can re-enable
8350 * tracing with echo 1 > tracing_on.
8354 local_irq_save(flags);
8355 printk_nmi_direct_enter();
8357 /* Simulate the iterator */
8358 trace_init_global_iter(&iter);
8360 for_each_tracing_cpu(cpu) {
8361 atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
8364 old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
8366 /* don't look at user memory in panic mode */
8367 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
8369 switch (oops_dump_mode) {
8371 iter.cpu_file = RING_BUFFER_ALL_CPUS;
8374 iter.cpu_file = raw_smp_processor_id();
8379 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
8380 iter.cpu_file = RING_BUFFER_ALL_CPUS;
8383 printk(KERN_TRACE "Dumping ftrace buffer:\n");
8385 /* Did function tracer already get disabled? */
8386 if (ftrace_is_dead()) {
8387 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
8388 printk("# MAY BE MISSING FUNCTION EVENTS\n");
8392 * We need to stop all tracing on all CPUS to read the
8393 * the next buffer. This is a bit expensive, but is
8394 * not done often. We fill all what we can read,
8395 * and then release the locks again.
8398 while (!trace_empty(&iter)) {
8401 printk(KERN_TRACE "---------------------------------\n");
8405 trace_iterator_reset(&iter);
8406 iter.iter_flags |= TRACE_FILE_LAT_FMT;
8408 if (trace_find_next_entry_inc(&iter) != NULL) {
8411 ret = print_trace_line(&iter);
8412 if (ret != TRACE_TYPE_NO_CONSUME)
8413 trace_consume(&iter);
8415 touch_nmi_watchdog();
8417 trace_printk_seq(&iter.seq);
8421 printk(KERN_TRACE " (ftrace buffer empty)\n");
8423 printk(KERN_TRACE "---------------------------------\n");
8426 tr->trace_flags |= old_userobj;
8428 for_each_tracing_cpu(cpu) {
8429 atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
8431 atomic_dec(&dump_running);
8432 printk_nmi_direct_exit();
8433 local_irq_restore(flags);
8435 EXPORT_SYMBOL_GPL(ftrace_dump);
8437 int trace_run_command(const char *buf, int (*createfn)(int, char **))
8444 argv = argv_split(GFP_KERNEL, buf, &argc);
8449 ret = createfn(argc, argv);
8456 #define WRITE_BUFSIZE 4096
8458 ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
8459 size_t count, loff_t *ppos,
8460 int (*createfn)(int, char **))
8462 char *kbuf, *buf, *tmp;
8467 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
8471 while (done < count) {
8472 size = count - done;
8474 if (size >= WRITE_BUFSIZE)
8475 size = WRITE_BUFSIZE - 1;
8477 if (copy_from_user(kbuf, buffer + done, size)) {
8484 tmp = strchr(buf, '\n');
8487 size = tmp - buf + 1;
8490 if (done + size < count) {
8493 /* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
8494 pr_warn("Line length is too long: Should be less than %d\n",
8502 /* Remove comments */
8503 tmp = strchr(buf, '#');
8508 ret = trace_run_command(buf, createfn);
8513 } while (done < count);
8523 __init static int tracer_alloc_buffers(void)
8529 * Make sure we don't accidently add more trace options
8530 * than we have bits for.
8532 BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
8534 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
8537 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
8538 goto out_free_buffer_mask;
8540 /* Only allocate trace_printk buffers if a trace_printk exists */
8541 if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
8542 /* Must be called before global_trace.buffer is allocated */
8543 trace_printk_init_buffers();
8545 /* To save memory, keep the ring buffer size to its minimum */
8546 if (ring_buffer_expanded)
8547 ring_buf_size = trace_buf_size;
8551 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
8552 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
8554 raw_spin_lock_init(&global_trace.start_lock);
8557 * The prepare callbacks allocates some memory for the ring buffer. We
8558 * don't free the buffer if the if the CPU goes down. If we were to free
8559 * the buffer, then the user would lose any trace that was in the
8560 * buffer. The memory will be removed once the "instance" is removed.
8562 ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
8563 "trace/RB:preapre", trace_rb_cpu_prepare,
8566 goto out_free_cpumask;
8567 /* Used for event triggers */
8569 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
8571 goto out_rm_hp_state;
8573 if (trace_create_savedcmd() < 0)
8574 goto out_free_temp_buffer;
8576 /* TODO: make the number of buffers hot pluggable with CPUS */
8577 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
8578 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
8580 goto out_free_savedcmd;
8583 if (global_trace.buffer_disabled)
8586 if (trace_boot_clock) {
8587 ret = tracing_set_clock(&global_trace, trace_boot_clock);
8589 pr_warn("Trace clock %s not defined, going back to default\n",
8594 * register_tracer() might reference current_trace, so it
8595 * needs to be set before we register anything. This is
8596 * just a bootstrap of current_trace anyway.
8598 global_trace.current_trace = &nop_trace;
8600 global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
8602 ftrace_init_global_array_ops(&global_trace);
8604 init_trace_flags_index(&global_trace);
8606 register_tracer(&nop_trace);
8608 /* Function tracing may start here (via kernel command line) */
8609 init_function_trace();
8611 /* All seems OK, enable tracing */
8612 tracing_disabled = 0;
8614 atomic_notifier_chain_register(&panic_notifier_list,
8615 &trace_panic_notifier);
8617 register_die_notifier(&trace_die_notifier);
8619 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
8621 INIT_LIST_HEAD(&global_trace.systems);
8622 INIT_LIST_HEAD(&global_trace.events);
8623 INIT_LIST_HEAD(&global_trace.hist_vars);
8624 list_add(&global_trace.list, &ftrace_trace_arrays);
8626 apply_trace_boot_options();
8628 register_snapshot_cmd();
8633 free_saved_cmdlines_buffer(savedcmd);
8634 out_free_temp_buffer:
8635 ring_buffer_free(temp_buffer);
8637 cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
8639 free_cpumask_var(global_trace.tracing_cpumask);
8640 out_free_buffer_mask:
8641 free_cpumask_var(tracing_buffer_mask);
8646 void __init early_trace_init(void)
8648 if (tracepoint_printk) {
8649 tracepoint_print_iter =
8650 kmalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
8651 if (WARN_ON(!tracepoint_print_iter))
8652 tracepoint_printk = 0;
8654 static_key_enable(&tracepoint_printk_key.key);
8656 tracer_alloc_buffers();
8659 void __init trace_init(void)
8664 __init static int clear_boot_tracer(void)
8667 * The default tracer at boot buffer is an init section.
8668 * This function is called in lateinit. If we did not
8669 * find the boot tracer, then clear it out, to prevent
8670 * later registration from accessing the buffer that is
8671 * about to be freed.
8673 if (!default_bootup_tracer)
8676 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
8677 default_bootup_tracer);
8678 default_bootup_tracer = NULL;
8683 fs_initcall(tracer_init_tracefs);
8684 late_initcall_sync(clear_boot_tracer);
8686 #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
8687 __init static int tracing_set_default_clock(void)
8689 /* sched_clock_stable() is determined in late_initcall */
8690 if (!trace_boot_clock && !sched_clock_stable()) {
8692 "Unstable clock detected, switching default tracing clock to \"global\"\n"
8693 "If you want to keep using the local clock, then add:\n"
8694 " \"trace_clock=local\"\n"
8695 "on the kernel command line\n");
8696 tracing_set_clock(&global_trace, "global");
8701 late_initcall_sync(tracing_set_default_clock);