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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2008 ARM Limited
4 * Copyright (C) 2014 Regents of the University of California
5 */
6
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>
14
15#include <asm/stacktrace.h>
16
17#ifdef CONFIG_FRAME_POINTER
18
19extern asmlinkage void ret_from_exception(void);
20
21void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
22 bool (*fn)(void *, unsigned long), void *arg)
23{
24 unsigned long fp, sp, pc;
25 int level = 0;
26
27 if (regs) {
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;
35 level = -1;
36 } else {
37 /* task blocked in __switch_to */
38 fp = task->thread.s[0];
39 sp = task->thread.sp;
40 pc = task->thread.ra;
41 }
42
43 for (;;) {
44 unsigned long low, high;
45 struct stackframe *frame;
46
47 if (unlikely(!__kernel_text_address(pc) || (level++ >= 0 && !fn(arg, pc))))
48 break;
49
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))
54 break;
55 /* Unwind stack frame */
56 frame = (struct stackframe *)fp - 1;
57 sp = fp;
58 if (regs && (regs->epc == pc) && (frame->fp & 0x7)) {
59 fp = frame->ra;
60 pc = regs->ra;
61 } else {
62 fp = frame->fp;
63 pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
64 &frame->ra);
65 if (pc == (unsigned long)ret_from_exception) {
66 if (unlikely(!__kernel_text_address(pc) || !fn(arg, pc)))
67 break;
68
69 pc = ((struct pt_regs *)sp)->epc;
70 fp = ((struct pt_regs *)sp)->s0;
71 }
72 }
73
74 }
75}
76
77#else /* !CONFIG_FRAME_POINTER */
78
79void notrace walk_stackframe(struct task_struct *task,
80 struct pt_regs *regs, bool (*fn)(void *, unsigned long), void *arg)
81{
82 unsigned long sp, pc;
83 unsigned long *ksp;
84
85 if (regs) {
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;
91 } else {
92 /* task blocked in __switch_to */
93 sp = task->thread.sp;
94 pc = task->thread.ra;
95 }
96
97 if (unlikely(sp & 0x7))
98 return;
99
100 ksp = (unsigned long *)sp;
101 while (!kstack_end(ksp)) {
102 if (__kernel_text_address(pc) && unlikely(!fn(arg, pc)))
103 break;
104 pc = (*ksp++) - 0x4;
105 }
106}
107
108#endif /* CONFIG_FRAME_POINTER */
109
110static bool print_trace_address(void *arg, unsigned long pc)
111{
112 const char *loglvl = arg;
113
114 print_ip_sym(loglvl, pc);
115 return true;
116}
117
118noinline void dump_backtrace(struct pt_regs *regs, struct task_struct *task,
119 const char *loglvl)
120{
121 walk_stackframe(task, regs, print_trace_address, (void *)loglvl);
122}
123
124void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
125{
126 pr_cont("%sCall Trace:\n", loglvl);
127 dump_backtrace(NULL, task, loglvl);
128}
129
130static bool save_wchan(void *arg, unsigned long pc)
131{
132 if (!in_sched_functions(pc)) {
133 unsigned long *p = arg;
134 *p = pc;
135 return false;
136 }
137 return true;
138}
139
140unsigned long __get_wchan(struct task_struct *task)
141{
142 unsigned long pc = 0;
143
144 if (!try_get_task_stack(task))
145 return 0;
146 walk_stackframe(task, NULL, save_wchan, &pc);
147 put_task_stack(task);
148 return pc;
149}
150
151noinline void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
152 struct task_struct *task, struct pt_regs *regs)
153{
154 walk_stackframe(task, regs, consume_entry, cookie);
155}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2008 ARM Limited
4 * Copyright (C) 2014 Regents of the University of California
5 */
6
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>
14
15#include <asm/stacktrace.h>
16
17#ifdef CONFIG_FRAME_POINTER
18
19extern asmlinkage void ret_from_exception(void);
20
21static inline int fp_is_valid(unsigned long fp, unsigned long sp)
22{
23 unsigned long low, high;
24
25 low = sp + sizeof(struct stackframe);
26 high = ALIGN(sp, THREAD_SIZE);
27
28 return !(fp < low || fp > high || fp & 0x07);
29}
30
31void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
32 bool (*fn)(void *, unsigned long), void *arg)
33{
34 unsigned long fp, sp, pc;
35 int level = 0;
36
37 if (regs) {
38 fp = frame_pointer(regs);
39 sp = user_stack_pointer(regs);
40 pc = instruction_pointer(regs);
41 } else if (task == NULL || task == current) {
42 fp = (unsigned long)__builtin_frame_address(0);
43 sp = current_stack_pointer;
44 pc = (unsigned long)walk_stackframe;
45 level = -1;
46 } else {
47 /* task blocked in __switch_to */
48 fp = task->thread.s[0];
49 sp = task->thread.sp;
50 pc = task->thread.ra;
51 }
52
53 for (;;) {
54 struct stackframe *frame;
55
56 if (unlikely(!__kernel_text_address(pc) || (level++ >= 0 && !fn(arg, pc))))
57 break;
58
59 if (unlikely(!fp_is_valid(fp, sp)))
60 break;
61
62 /* Unwind stack frame */
63 frame = (struct stackframe *)fp - 1;
64 sp = fp;
65 if (regs && (regs->epc == pc) && fp_is_valid(frame->ra, sp)) {
66 /* We hit function where ra is not saved on the stack */
67 fp = frame->ra;
68 pc = regs->ra;
69 } else {
70 fp = frame->fp;
71 pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
72 &frame->ra);
73 if (pc == (unsigned long)ret_from_exception) {
74 if (unlikely(!__kernel_text_address(pc) || !fn(arg, pc)))
75 break;
76
77 pc = ((struct pt_regs *)sp)->epc;
78 fp = ((struct pt_regs *)sp)->s0;
79 }
80 }
81
82 }
83}
84
85#else /* !CONFIG_FRAME_POINTER */
86
87void notrace walk_stackframe(struct task_struct *task,
88 struct pt_regs *regs, bool (*fn)(void *, unsigned long), void *arg)
89{
90 unsigned long sp, pc;
91 unsigned long *ksp;
92
93 if (regs) {
94 sp = user_stack_pointer(regs);
95 pc = instruction_pointer(regs);
96 } else if (task == NULL || task == current) {
97 sp = current_stack_pointer;
98 pc = (unsigned long)walk_stackframe;
99 } else {
100 /* task blocked in __switch_to */
101 sp = task->thread.sp;
102 pc = task->thread.ra;
103 }
104
105 if (unlikely(sp & 0x7))
106 return;
107
108 ksp = (unsigned long *)sp;
109 while (!kstack_end(ksp)) {
110 if (__kernel_text_address(pc) && unlikely(!fn(arg, pc)))
111 break;
112 pc = READ_ONCE_NOCHECK(*ksp++) - 0x4;
113 }
114}
115
116#endif /* CONFIG_FRAME_POINTER */
117
118static bool print_trace_address(void *arg, unsigned long pc)
119{
120 const char *loglvl = arg;
121
122 print_ip_sym(loglvl, pc);
123 return true;
124}
125
126noinline void dump_backtrace(struct pt_regs *regs, struct task_struct *task,
127 const char *loglvl)
128{
129 walk_stackframe(task, regs, print_trace_address, (void *)loglvl);
130}
131
132void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
133{
134 pr_cont("%sCall Trace:\n", loglvl);
135 dump_backtrace(NULL, task, loglvl);
136}
137
138static bool save_wchan(void *arg, unsigned long pc)
139{
140 if (!in_sched_functions(pc)) {
141 unsigned long *p = arg;
142 *p = pc;
143 return false;
144 }
145 return true;
146}
147
148unsigned long __get_wchan(struct task_struct *task)
149{
150 unsigned long pc = 0;
151
152 if (!try_get_task_stack(task))
153 return 0;
154 walk_stackframe(task, NULL, save_wchan, &pc);
155 put_task_stack(task);
156 return pc;
157}
158
159noinline void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
160 struct task_struct *task, struct pt_regs *regs)
161{
162 walk_stackframe(task, regs, consume_entry, cookie);
163}