1 // SPDX-License-Identifier: GPL-2.0
3 #include <linux/sched/debug.h>
4 #include <linux/sched/task_stack.h>
5 #include <linux/stacktrace.h>
6 #include <linux/ftrace.h>
7 #include <linux/ptrace.h>
9 #ifdef CONFIG_FRAME_POINTER
16 void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
17 bool (*fn)(unsigned long, void *), void *arg)
19 unsigned long fp, sp, pc;
22 fp = frame_pointer(regs);
23 sp = user_stack_pointer(regs);
24 pc = instruction_pointer(regs);
25 } else if (task == NULL || task == current) {
26 const register unsigned long current_sp __asm__ ("sp");
27 const register unsigned long current_fp __asm__ ("r8");
30 pc = (unsigned long)walk_stackframe;
32 /* task blocked in __switch_to */
33 fp = thread_saved_fp(task);
34 sp = thread_saved_sp(task);
35 pc = thread_saved_lr(task);
39 unsigned long low, high;
40 struct stackframe *frame;
42 if (unlikely(!__kernel_text_address(pc) || fn(pc, arg)))
45 /* Validate frame pointer */
47 high = ALIGN(sp, THREAD_SIZE);
48 if (unlikely(fp < low || fp > high || fp & 0x3))
50 /* Unwind stack frame */
51 frame = (struct stackframe *)fp;
54 pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
55 (unsigned long *)(fp - 8));
59 #else /* !CONFIG_FRAME_POINTER */
61 static void notrace walk_stackframe(struct task_struct *task,
62 struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg)
68 sp = user_stack_pointer(regs);
69 pc = instruction_pointer(regs);
70 } else if (task == NULL || task == current) {
71 const register unsigned long current_sp __asm__ ("sp");
73 pc = (unsigned long)walk_stackframe;
75 /* task blocked in __switch_to */
76 sp = thread_saved_sp(task);
77 pc = thread_saved_lr(task);
80 if (unlikely(sp & 0x3))
83 ksp = (unsigned long *)sp;
84 while (!kstack_end(ksp)) {
85 if (__kernel_text_address(pc) && unlikely(fn(pc, arg)))
90 #endif /* CONFIG_FRAME_POINTER */
92 static bool print_trace_address(unsigned long pc, void *arg)
94 print_ip_sym((const char *)arg, pc);
98 void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
100 pr_cont("Call Trace:\n");
101 walk_stackframe(task, NULL, print_trace_address, (void *)loglvl);
104 static bool save_wchan(unsigned long pc, void *arg)
106 if (!in_sched_functions(pc)) {
107 unsigned long *p = arg;
114 unsigned long __get_wchan(struct task_struct *task)
116 unsigned long pc = 0;
118 walk_stackframe(task, NULL, save_wchan, &pc);
122 #ifdef CONFIG_STACKTRACE
123 static bool __save_trace(unsigned long pc, void *arg, bool nosched)
125 struct stack_trace *trace = arg;
127 if (unlikely(nosched && in_sched_functions(pc)))
129 if (unlikely(trace->skip > 0)) {
134 trace->entries[trace->nr_entries++] = pc;
135 return (trace->nr_entries >= trace->max_entries);
138 static bool save_trace(unsigned long pc, void *arg)
140 return __save_trace(pc, arg, false);
144 * Save stack-backtrace addresses into a stack_trace buffer.
146 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
148 walk_stackframe(tsk, NULL, save_trace, trace);
150 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
152 void save_stack_trace(struct stack_trace *trace)
154 save_stack_trace_tsk(NULL, trace);
156 EXPORT_SYMBOL_GPL(save_stack_trace);
158 #endif /* CONFIG_STACKTRACE */