Loading...
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
15register unsigned long sp_in_global __asm__("sp");
16
17#ifdef CONFIG_FRAME_POINTER
18
19struct stackframe {
20 unsigned long fp;
21 unsigned long ra;
22};
23
24void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
25 bool (*fn)(unsigned long, void *), void *arg)
26{
27 unsigned long fp, sp, pc;
28
29 if (regs) {
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);
36 sp = current_sp;
37 pc = (unsigned long)walk_stackframe;
38 } else {
39 /* task blocked in __switch_to */
40 fp = task->thread.s[0];
41 sp = task->thread.sp;
42 pc = task->thread.ra;
43 }
44
45 for (;;) {
46 unsigned long low, high;
47 struct stackframe *frame;
48
49 if (unlikely(!__kernel_text_address(pc) || fn(pc, arg)))
50 break;
51
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))
56 break;
57 /* Unwind stack frame */
58 frame = (struct stackframe *)fp - 1;
59 sp = fp;
60 fp = frame->fp;
61 pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
62 (unsigned long *)(fp - 8));
63 }
64}
65
66#else /* !CONFIG_FRAME_POINTER */
67
68void notrace walk_stackframe(struct task_struct *task,
69 struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg)
70{
71 unsigned long sp, pc;
72 unsigned long *ksp;
73
74 if (regs) {
75 sp = user_stack_pointer(regs);
76 pc = instruction_pointer(regs);
77 } else if (task == NULL || task == current) {
78 sp = sp_in_global;
79 pc = (unsigned long)walk_stackframe;
80 } else {
81 /* task blocked in __switch_to */
82 sp = task->thread.sp;
83 pc = task->thread.ra;
84 }
85
86 if (unlikely(sp & 0x7))
87 return;
88
89 ksp = (unsigned long *)sp;
90 while (!kstack_end(ksp)) {
91 if (__kernel_text_address(pc) && unlikely(fn(pc, arg)))
92 break;
93 pc = (*ksp++) - 0x4;
94 }
95}
96
97#endif /* CONFIG_FRAME_POINTER */
98
99
100static bool print_trace_address(unsigned long pc, void *arg)
101{
102 const char *loglvl = arg;
103
104 print_ip_sym(loglvl, pc);
105 return false;
106}
107
108void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
109{
110 pr_cont("Call Trace:\n");
111 walk_stackframe(task, NULL, print_trace_address, (void *)loglvl);
112}
113
114static bool save_wchan(unsigned long pc, void *arg)
115{
116 if (!in_sched_functions(pc)) {
117 unsigned long *p = arg;
118 *p = pc;
119 return true;
120 }
121 return false;
122}
123
124unsigned long get_wchan(struct task_struct *task)
125{
126 unsigned long pc = 0;
127
128 if (likely(task && task != current && task->state != TASK_RUNNING))
129 walk_stackframe(task, NULL, save_wchan, &pc);
130 return pc;
131}
132
133
134#ifdef CONFIG_STACKTRACE
135
136static bool __save_trace(unsigned long pc, void *arg, bool nosched)
137{
138 struct stack_trace *trace = arg;
139
140 if (unlikely(nosched && in_sched_functions(pc)))
141 return false;
142 if (unlikely(trace->skip > 0)) {
143 trace->skip--;
144 return false;
145 }
146
147 trace->entries[trace->nr_entries++] = pc;
148 return (trace->nr_entries >= trace->max_entries);
149}
150
151static bool save_trace(unsigned long pc, void *arg)
152{
153 return __save_trace(pc, arg, false);
154}
155
156/*
157 * Save stack-backtrace addresses into a stack_trace buffer.
158 */
159void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
160{
161 walk_stackframe(tsk, NULL, save_trace, trace);
162}
163EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
164
165void save_stack_trace(struct stack_trace *trace)
166{
167 save_stack_trace_tsk(NULL, trace);
168}
169EXPORT_SYMBOL_GPL(save_stack_trace);
170
171#endif /* CONFIG_STACKTRACE */
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#ifdef CONFIG_FRAME_POINTER
16
17struct stackframe {
18 unsigned long fp;
19 unsigned long ra;
20};
21
22void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
23 bool (*fn)(unsigned long, void *), void *arg)
24{
25 unsigned long fp, sp, pc;
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 const register unsigned long current_sp __asm__ ("sp");
33 fp = (unsigned long)__builtin_frame_address(0);
34 sp = current_sp;
35 pc = (unsigned long)walk_stackframe;
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) || fn(pc, arg)))
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 fp = frame->fp;
59 pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
60 (unsigned long *)(fp - 8));
61 }
62}
63
64#else /* !CONFIG_FRAME_POINTER */
65
66static void notrace walk_stackframe(struct task_struct *task,
67 struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg)
68{
69 unsigned long sp, pc;
70 unsigned long *ksp;
71
72 if (regs) {
73 sp = user_stack_pointer(regs);
74 pc = instruction_pointer(regs);
75 } else if (task == NULL || task == current) {
76 const register unsigned long current_sp __asm__ ("sp");
77 sp = current_sp;
78 pc = (unsigned long)walk_stackframe;
79 } else {
80 /* task blocked in __switch_to */
81 sp = task->thread.sp;
82 pc = task->thread.ra;
83 }
84
85 if (unlikely(sp & 0x7))
86 return;
87
88 ksp = (unsigned long *)sp;
89 while (!kstack_end(ksp)) {
90 if (__kernel_text_address(pc) && unlikely(fn(pc, arg)))
91 break;
92 pc = (*ksp++) - 0x4;
93 }
94}
95
96#endif /* CONFIG_FRAME_POINTER */
97
98
99static bool print_trace_address(unsigned long pc, void *arg)
100{
101 print_ip_sym(pc);
102 return false;
103}
104
105void show_stack(struct task_struct *task, unsigned long *sp)
106{
107 pr_cont("Call Trace:\n");
108 walk_stackframe(task, NULL, print_trace_address, NULL);
109}
110
111
112static bool save_wchan(unsigned long pc, void *arg)
113{
114 if (!in_sched_functions(pc)) {
115 unsigned long *p = arg;
116 *p = pc;
117 return true;
118 }
119 return false;
120}
121
122unsigned long get_wchan(struct task_struct *task)
123{
124 unsigned long pc = 0;
125
126 if (likely(task && task != current && task->state != TASK_RUNNING))
127 walk_stackframe(task, NULL, save_wchan, &pc);
128 return pc;
129}
130
131
132#ifdef CONFIG_STACKTRACE
133
134static bool __save_trace(unsigned long pc, void *arg, bool nosched)
135{
136 struct stack_trace *trace = arg;
137
138 if (unlikely(nosched && in_sched_functions(pc)))
139 return false;
140 if (unlikely(trace->skip > 0)) {
141 trace->skip--;
142 return false;
143 }
144
145 trace->entries[trace->nr_entries++] = pc;
146 return (trace->nr_entries >= trace->max_entries);
147}
148
149static bool save_trace(unsigned long pc, void *arg)
150{
151 return __save_trace(pc, arg, false);
152}
153
154/*
155 * Save stack-backtrace addresses into a stack_trace buffer.
156 */
157void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
158{
159 walk_stackframe(tsk, NULL, save_trace, trace);
160}
161EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
162
163void save_stack_trace(struct stack_trace *trace)
164{
165 save_stack_trace_tsk(NULL, trace);
166}
167EXPORT_SYMBOL_GPL(save_stack_trace);
168
169#endif /* CONFIG_STACKTRACE */