kernel/trace/trace_mmiotrace.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Memory mapped I/O tracing
   4  *
   5  * Copyright (C) 2008 Pekka Paalanen <pq@iki.fi>
   6  */
   7
   8 #define DEBUG 1
   9
  10 #include <linux/kernel.h>
  11 #include <linux/mmiotrace.h>
  12 #include <linux/pci.h>
  13 #include <linux/slab.h>
  14 #include <linux/time.h>
  15
  16 #include <linux/atomic.h>
  17
  18 #include "trace.h"
  19 #include "trace_output.h"
  20
  21 struct header_iter {
  22         struct pci_dev *dev;
  23 };
  24
  25 static struct trace_array *mmio_trace_array;
  26 static bool overrun_detected;
  27 static unsigned long prev_overruns;
  28 static atomic_t dropped_count;
  29
  30 static void mmio_reset_data(struct trace_array *tr)
  31 {
  32         overrun_detected = false;
  33         prev_overruns = 0;
  34
  35         tracing_reset_online_cpus(&tr->trace_buffer);
  36 }
  37
  38 static int mmio_trace_init(struct trace_array *tr)
  39 {
  40         pr_debug("in %s\n", __func__);
  41         mmio_trace_array = tr;
  42
  43         mmio_reset_data(tr);
  44         enable_mmiotrace();
  45         return 0;
  46 }
  47
  48 static void mmio_trace_reset(struct trace_array *tr)
  49 {
  50         pr_debug("in %s\n", __func__);
  51
  52         disable_mmiotrace();
  53         mmio_reset_data(tr);
  54         mmio_trace_array = NULL;
  55 }
  56
  57 static void mmio_trace_start(struct trace_array *tr)
  58 {
  59         pr_debug("in %s\n", __func__);
  60         mmio_reset_data(tr);
  61 }
  62
  63 static void mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  64 {
  65         int i;
  66         resource_size_t start, end;
  67         const struct pci_driver *drv = pci_dev_driver(dev);
  68
  69         trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
  70                          dev->bus->number, dev->devfn,
  71                          dev->vendor, dev->device, dev->irq);
  72         for (i = 0; i < 7; i++) {
  73                 start = dev->resource[i].start;
  74                 trace_seq_printf(s, " %llx",
  75                         (unsigned long long)(start |
  76                         (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
  77         }
  78         for (i = 0; i < 7; i++) {
  79                 start = dev->resource[i].start;
  80                 end = dev->resource[i].end;
  81                 trace_seq_printf(s, " %llx",
  82                         dev->resource[i].start < dev->resource[i].end ?
  83                         (unsigned long long)(end - start) + 1 : 0);
  84         }
  85         if (drv)
  86                 trace_seq_printf(s, " %s\n", drv->name);
  87         else
  88                 trace_seq_puts(s, " \n");
  89 }
  90
  91 static void destroy_header_iter(struct header_iter *hiter)
  92 {
  93         if (!hiter)
  94                 return;
  95         pci_dev_put(hiter->dev);
  96         kfree(hiter);
  97 }
  98
  99 static void mmio_pipe_open(struct trace_iterator *iter)
 100 {
 101         struct header_iter *hiter;
 102         struct trace_seq *s = &iter->seq;
 103
 104         trace_seq_puts(s, "VERSION 20070824\n");
 105
 106         hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
 107         if (!hiter)
 108                 return;
 109
 110         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
 111         iter->private = hiter;
 112 }
 113
 114 /* XXX: This is not called when the pipe is closed! */
 115 static void mmio_close(struct trace_iterator *iter)
 116 {
 117         struct header_iter *hiter = iter->private;
 118         destroy_header_iter(hiter);
 119         iter->private = NULL;
 120 }
 121
 122 static unsigned long count_overruns(struct trace_iterator *iter)
 123 {
 124         unsigned long cnt = atomic_xchg(&dropped_count, 0);
 125         unsigned long over = ring_buffer_overruns(iter->trace_buffer->buffer);
 126
 127         if (over > prev_overruns)
 128                 cnt += over - prev_overruns;
 129         prev_overruns = over;
 130         return cnt;
 131 }
 132
 133 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
 134                                 char __user *ubuf, size_t cnt, loff_t *ppos)
 135 {
 136         ssize_t ret;
 137         struct header_iter *hiter = iter->private;
 138         struct trace_seq *s = &iter->seq;
 139         unsigned long n;
 140
 141         n = count_overruns(iter);
 142         if (n) {
 143                 /* XXX: This is later than where events were lost. */
 144                 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
 145                 if (!overrun_detected)
 146                         pr_warn("mmiotrace has lost events\n");
 147                 overrun_detected = true;
 148                 goto print_out;
 149         }
 150
 151         if (!hiter)
 152                 return 0;
 153
 154         mmio_print_pcidev(s, hiter->dev);
 155         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
 156
 157         if (!hiter->dev) {
 158                 destroy_header_iter(hiter);
 159                 iter->private = NULL;
 160         }
 161
 162 print_out:
 163         ret = trace_seq_to_user(s, ubuf, cnt);
 164         return (ret == -EBUSY) ? 0 : ret;
 165 }
 166
 167 static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 168 {
 169         struct trace_entry *entry = iter->ent;
 170         struct trace_mmiotrace_rw *field;
 171         struct mmiotrace_rw *rw;
 172         struct trace_seq *s     = &iter->seq;
 173         unsigned long long t    = ns2usecs(iter->ts);
 174         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 175         unsigned secs           = (unsigned long)t;
 176
 177         trace_assign_type(field, entry);
 178         rw = &field->rw;
 179
 180         switch (rw->opcode) {
 181         case MMIO_READ:
 182                 trace_seq_printf(s,
 183                         "R %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 184                         rw->width, secs, usec_rem, rw->map_id,
 185                         (unsigned long long)rw->phys,
 186                         rw->value, rw->pc, 0);
 187                 break;
 188         case MMIO_WRITE:
 189                 trace_seq_printf(s,
 190                         "W %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 191                         rw->width, secs, usec_rem, rw->map_id,
 192                         (unsigned long long)rw->phys,
 193                         rw->value, rw->pc, 0);
 194                 break;
 195         case MMIO_UNKNOWN_OP:
 196                 trace_seq_printf(s,
 197                         "UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
 198                         "%02lx 0x%lx %d\n",
 199                         secs, usec_rem, rw->map_id,
 200                         (unsigned long long)rw->phys,
 201                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
 202                         (rw->value >> 0) & 0xff, rw->pc, 0);
 203                 break;
 204         default:
 205                 trace_seq_puts(s, "rw what?\n");
 206                 break;
 207         }
 208
 209         return trace_handle_return(s);
 210 }
 211
 212 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 213 {
 214         struct trace_entry *entry = iter->ent;
 215         struct trace_mmiotrace_map *field;
 216         struct mmiotrace_map *m;
 217         struct trace_seq *s     = &iter->seq;
 218         unsigned long long t    = ns2usecs(iter->ts);
 219         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 220         unsigned secs           = (unsigned long)t;
 221
 222         trace_assign_type(field, entry);
 223         m = &field->map;
 224
 225         switch (m->opcode) {
 226         case MMIO_PROBE:
 227                 trace_seq_printf(s,
 228                         "MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 229                         secs, usec_rem, m->map_id,
 230                         (unsigned long long)m->phys, m->virt, m->len,
 231                         0UL, 0);
 232                 break;
 233         case MMIO_UNPROBE:
 234                 trace_seq_printf(s,
 235                         "UNMAP %u.%06lu %d 0x%lx %d\n",
 236                         secs, usec_rem, m->map_id, 0UL, 0);
 237                 break;
 238         default:
 239                 trace_seq_puts(s, "map what?\n");
 240                 break;
 241         }
 242
 243         return trace_handle_return(s);
 244 }
 245
 246 static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 247 {
 248         struct trace_entry *entry = iter->ent;
 249         struct print_entry *print = (struct print_entry *)entry;
 250         const char *msg         = print->buf;
 251         struct trace_seq *s     = &iter->seq;
 252         unsigned long long t    = ns2usecs(iter->ts);
 253         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 254         unsigned secs           = (unsigned long)t;
 255
 256         /* The trailing newline must be in the message. */
 257         trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
 258
 259         return trace_handle_return(s);
 260 }
 261
 262 static enum print_line_t mmio_print_line(struct trace_iterator *iter)
 263 {
 264         switch (iter->ent->type) {
 265         case TRACE_MMIO_RW:
 266                 return mmio_print_rw(iter);
 267         case TRACE_MMIO_MAP:
 268                 return mmio_print_map(iter);
 269         case TRACE_PRINT:
 270                 return mmio_print_mark(iter);
 271         default:
 272                 return TRACE_TYPE_HANDLED; /* ignore unknown entries */
 273         }
 274 }
 275
 276 static struct tracer mmio_tracer __read_mostly =
 277 {
 278         .name           = "mmiotrace",
 279         .init           = mmio_trace_init,
 280         .reset          = mmio_trace_reset,
 281         .start          = mmio_trace_start,
 282         .pipe_open      = mmio_pipe_open,
 283         .close          = mmio_close,
 284         .read           = mmio_read,
 285         .print_line     = mmio_print_line,
 286         .noboot         = true,
 287 };
 288
 289 __init static int init_mmio_trace(void)
 290 {
 291         return register_tracer(&mmio_tracer);
 292 }
 293 device_initcall(init_mmio_trace);
 294
 295 static void __trace_mmiotrace_rw(struct trace_array *tr,
 296                                 struct trace_array_cpu *data,
 297                                 struct mmiotrace_rw *rw)
 298 {
 299         struct trace_event_call *call = &event_mmiotrace_rw;
 300         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 301         struct ring_buffer_event *event;
 302         struct trace_mmiotrace_rw *entry;
 303         int pc = preempt_count();
 304
 305         event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,
 306                                           sizeof(*entry), 0, pc);
 307         if (!event) {
 308                 atomic_inc(&dropped_count);
 309                 return;
 310         }
 311         entry   = ring_buffer_event_data(event);
 312         entry->rw                       = *rw;
 313
 314         if (!call_filter_check_discard(call, entry, buffer, event))
 315                 trace_buffer_unlock_commit(tr, buffer, event, 0, pc);
 316 }
 317
 318 void mmio_trace_rw(struct mmiotrace_rw *rw)
 319 {
 320         struct trace_array *tr = mmio_trace_array;
 321         struct trace_array_cpu *data = per_cpu_ptr(tr->trace_buffer.data, smp_processor_id());
 322         __trace_mmiotrace_rw(tr, data, rw);
 323 }
 324
 325 static void __trace_mmiotrace_map(struct trace_array *tr,
 326                                 struct trace_array_cpu *data,
 327                                 struct mmiotrace_map *map)
 328 {
 329         struct trace_event_call *call = &event_mmiotrace_map;
 330         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 331         struct ring_buffer_event *event;
 332         struct trace_mmiotrace_map *entry;
 333         int pc = preempt_count();
 334
 335         event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,
 336                                           sizeof(*entry), 0, pc);
 337         if (!event) {
 338                 atomic_inc(&dropped_count);
 339                 return;
 340         }
 341         entry   = ring_buffer_event_data(event);
 342         entry->map                      = *map;
 343
 344         if (!call_filter_check_discard(call, entry, buffer, event))
 345                 trace_buffer_unlock_commit(tr, buffer, event, 0, pc);
 346 }
 347
 348 void mmio_trace_mapping(struct mmiotrace_map *map)
 349 {
 350         struct trace_array *tr = mmio_trace_array;
 351         struct trace_array_cpu *data;
 352
 353         preempt_disable();
 354         data = per_cpu_ptr(tr->trace_buffer.data, smp_processor_id());
 355         __trace_mmiotrace_map(tr, data, map);
 356         preempt_enable();
 357 }
 358
 359 int mmio_trace_printk(const char *fmt, va_list args)
 360 {
 361         return trace_vprintk(0, fmt, args);
 362 }