1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2008 ARM Limited
4 * Copyright (C) 2014 Regents of the University of California
7 #include <linux/export.h>
8 #include <linux/kallsyms.h>
9 #include <linux/sched.h>
10 #include <linux/sched/debug.h>
11 #include <linux/sched/task_stack.h>
12 #include <linux/stacktrace.h>
13 #include <linux/ftrace.h>
15 #include <asm/stacktrace.h>
17 #ifdef CONFIG_FRAME_POINTER
19 extern asmlinkage void ret_from_exception(void);
21 void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
22 bool (*fn)(void *, unsigned long), void *arg)
24 unsigned long fp, sp, pc;
28 fp = frame_pointer(regs);
29 sp = user_stack_pointer(regs);
30 pc = instruction_pointer(regs);
31 } else if (task == NULL || task == current) {
32 fp = (unsigned long)__builtin_frame_address(0);
33 sp = current_stack_pointer;
34 pc = (unsigned long)walk_stackframe;
37 /* task blocked in __switch_to */
38 fp = task->thread.s[0];
44 unsigned long low, high;
45 struct stackframe *frame;
47 if (unlikely(!__kernel_text_address(pc) || (level++ >= 0 && !fn(arg, pc))))
50 /* Validate frame pointer */
51 low = sp + sizeof(struct stackframe);
52 high = ALIGN(sp, THREAD_SIZE);
53 if (unlikely(fp < low || fp > high || fp & 0x7))
55 /* Unwind stack frame */
56 frame = (struct stackframe *)fp - 1;
58 if (regs && (regs->epc == pc) && (frame->fp & 0x7)) {
63 pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
65 if (pc == (unsigned long)ret_from_exception) {
66 if (unlikely(!__kernel_text_address(pc) || !fn(arg, pc)))
69 pc = ((struct pt_regs *)sp)->epc;
70 fp = ((struct pt_regs *)sp)->s0;
77 #else /* !CONFIG_FRAME_POINTER */
79 void notrace walk_stackframe(struct task_struct *task,
80 struct pt_regs *regs, bool (*fn)(void *, unsigned long), void *arg)
86 sp = user_stack_pointer(regs);
87 pc = instruction_pointer(regs);
88 } else if (task == NULL || task == current) {
89 sp = current_stack_pointer;
90 pc = (unsigned long)walk_stackframe;
92 /* task blocked in __switch_to */
97 if (unlikely(sp & 0x7))
100 ksp = (unsigned long *)sp;
101 while (!kstack_end(ksp)) {
102 if (__kernel_text_address(pc) && unlikely(!fn(arg, pc)))
104 pc = READ_ONCE_NOCHECK(*ksp++) - 0x4;
108 #endif /* CONFIG_FRAME_POINTER */
110 static bool print_trace_address(void *arg, unsigned long pc)
112 const char *loglvl = arg;
114 print_ip_sym(loglvl, pc);
118 noinline void dump_backtrace(struct pt_regs *regs, struct task_struct *task,
121 walk_stackframe(task, regs, print_trace_address, (void *)loglvl);
124 void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
126 pr_cont("%sCall Trace:\n", loglvl);
127 dump_backtrace(NULL, task, loglvl);
130 static bool save_wchan(void *arg, unsigned long pc)
132 if (!in_sched_functions(pc)) {
133 unsigned long *p = arg;
140 unsigned long __get_wchan(struct task_struct *task)
142 unsigned long pc = 0;
144 if (!try_get_task_stack(task))
146 walk_stackframe(task, NULL, save_wchan, &pc);
147 put_task_stack(task);
151 noinline void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
152 struct task_struct *task, struct pt_regs *regs)
154 walk_stackframe(task, regs, consume_entry, cookie);