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 register unsigned long sp_in_global __asm__("sp");
17 #ifdef CONFIG_FRAME_POINTER
24 void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
25 bool (*fn)(unsigned long, void *), void *arg)
27 unsigned long fp, sp, pc;
30 fp = frame_pointer(regs);
31 sp = user_stack_pointer(regs);
32 pc = instruction_pointer(regs);
33 } else if (task == NULL || task == current) {
34 const register unsigned long current_sp = sp_in_global;
35 fp = (unsigned long)__builtin_frame_address(0);
37 pc = (unsigned long)walk_stackframe;
39 /* task blocked in __switch_to */
40 fp = task->thread.s[0];
46 unsigned long low, high;
47 struct stackframe *frame;
49 if (unlikely(!__kernel_text_address(pc) || fn(pc, arg)))
52 /* Validate frame pointer */
53 low = sp + sizeof(struct stackframe);
54 high = ALIGN(sp, THREAD_SIZE);
55 if (unlikely(fp < low || fp > high || fp & 0x7))
57 /* Unwind stack frame */
58 frame = (struct stackframe *)fp - 1;
61 pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
62 (unsigned long *)(fp - 8));
66 #else /* !CONFIG_FRAME_POINTER */
68 void notrace walk_stackframe(struct task_struct *task,
69 struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg)
75 sp = user_stack_pointer(regs);
76 pc = instruction_pointer(regs);
77 } else if (task == NULL || task == current) {
79 pc = (unsigned long)walk_stackframe;
81 /* task blocked in __switch_to */
86 if (unlikely(sp & 0x7))
89 ksp = (unsigned long *)sp;
90 while (!kstack_end(ksp)) {
91 if (__kernel_text_address(pc) && unlikely(fn(pc, arg)))
97 #endif /* CONFIG_FRAME_POINTER */
100 static bool print_trace_address(unsigned long pc, void *arg)
102 const char *loglvl = arg;
104 print_ip_sym(loglvl, pc);
108 void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
110 pr_cont("Call Trace:\n");
111 walk_stackframe(task, NULL, print_trace_address, (void *)loglvl);
114 static bool save_wchan(unsigned long pc, void *arg)
116 if (!in_sched_functions(pc)) {
117 unsigned long *p = arg;
124 unsigned long get_wchan(struct task_struct *task)
126 unsigned long pc = 0;
128 if (likely(task && task != current && task->state != TASK_RUNNING))
129 walk_stackframe(task, NULL, save_wchan, &pc);
134 #ifdef CONFIG_STACKTRACE
136 static bool __save_trace(unsigned long pc, void *arg, bool nosched)
138 struct stack_trace *trace = arg;
140 if (unlikely(nosched && in_sched_functions(pc)))
142 if (unlikely(trace->skip > 0)) {
147 trace->entries[trace->nr_entries++] = pc;
148 return (trace->nr_entries >= trace->max_entries);
151 static bool save_trace(unsigned long pc, void *arg)
153 return __save_trace(pc, arg, false);
157 * Save stack-backtrace addresses into a stack_trace buffer.
159 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
161 walk_stackframe(tsk, NULL, save_trace, trace);
163 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
165 void save_stack_trace(struct stack_trace *trace)
167 save_stack_trace_tsk(NULL, trace);
169 EXPORT_SYMBOL_GPL(save_stack_trace);
171 #endif /* CONFIG_STACKTRACE */