1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2008 ARM Limited
* Copyright (C) 2014 Regents of the University of California
*/
#include <linux/export.h>
#include <linux/kallsyms.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
#include <linux/stacktrace.h>
#include <linux/ftrace.h>
#include <asm/stacktrace.h>
#ifdef CONFIG_FRAME_POINTER
extern asmlinkage void ret_from_exception(void);
void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
bool (*fn)(void *, unsigned long), void *arg)
{
unsigned long fp, sp, pc;
int level = 0;
if (regs) {
fp = frame_pointer(regs);
sp = user_stack_pointer(regs);
pc = instruction_pointer(regs);
} else if (task == NULL || task == current) {
fp = (unsigned long)__builtin_frame_address(0);
sp = current_stack_pointer;
pc = (unsigned long)walk_stackframe;
level = -1;
} else {
/* task blocked in __switch_to */
fp = task->thread.s[0];
sp = task->thread.sp;
pc = task->thread.ra;
}
for (;;) {
unsigned long low, high;
struct stackframe *frame;
if (unlikely(!__kernel_text_address(pc) || (level++ >= 0 && !fn(arg, pc))))
break;
/* Validate frame pointer */
low = sp + sizeof(struct stackframe);
high = ALIGN(sp, THREAD_SIZE);
if (unlikely(fp < low || fp > high || fp & 0x7))
break;
/* Unwind stack frame */
frame = (struct stackframe *)fp - 1;
sp = fp;
if (regs && (regs->epc == pc) && (frame->fp & 0x7)) {
fp = frame->ra;
pc = regs->ra;
} else {
fp = frame->fp;
pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
&frame->ra);
if (pc == (unsigned long)ret_from_exception) {
if (unlikely(!__kernel_text_address(pc) || !fn(arg, pc)))
break;
pc = ((struct pt_regs *)sp)->epc;
fp = ((struct pt_regs *)sp)->s0;
}
}
}
}
#else /* !CONFIG_FRAME_POINTER */
void notrace walk_stackframe(struct task_struct *task,
struct pt_regs *regs, bool (*fn)(void *, unsigned long), void *arg)
{
unsigned long sp, pc;
unsigned long *ksp;
if (regs) {
sp = user_stack_pointer(regs);
pc = instruction_pointer(regs);
} else if (task == NULL || task == current) {
sp = current_stack_pointer;
pc = (unsigned long)walk_stackframe;
} else {
/* task blocked in __switch_to */
sp = task->thread.sp;
pc = task->thread.ra;
}
if (unlikely(sp & 0x7))
return;
ksp = (unsigned long *)sp;
while (!kstack_end(ksp)) {
if (__kernel_text_address(pc) && unlikely(!fn(arg, pc)))
break;
pc = READ_ONCE_NOCHECK(*ksp++) - 0x4;
}
}
#endif /* CONFIG_FRAME_POINTER */
static bool print_trace_address(void *arg, unsigned long pc)
{
const char *loglvl = arg;
print_ip_sym(loglvl, pc);
return true;
}
noinline void dump_backtrace(struct pt_regs *regs, struct task_struct *task,
const char *loglvl)
{
walk_stackframe(task, regs, print_trace_address, (void *)loglvl);
}
void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
{
pr_cont("%sCall Trace:\n", loglvl);
dump_backtrace(NULL, task, loglvl);
}
static bool save_wchan(void *arg, unsigned long pc)
{
if (!in_sched_functions(pc)) {
unsigned long *p = arg;
*p = pc;
return false;
}
return true;
}
unsigned long __get_wchan(struct task_struct *task)
{
unsigned long pc = 0;
if (!try_get_task_stack(task))
return 0;
walk_stackframe(task, NULL, save_wchan, &pc);
put_task_stack(task);
return pc;
}
noinline void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
struct task_struct *task, struct pt_regs *regs)
{
walk_stackframe(task, regs, consume_entry, cookie);
}
|
