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
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2012 ARM Ltd.
*/
#ifndef __ASM_STACKTRACE_H
#define __ASM_STACKTRACE_H
#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/types.h>
#include <asm/memory.h>
#include <asm/ptrace.h>
#include <asm/sdei.h>
enum stack_type {
STACK_TYPE_UNKNOWN,
STACK_TYPE_TASK,
STACK_TYPE_IRQ,
STACK_TYPE_OVERFLOW,
STACK_TYPE_SDEI_NORMAL,
STACK_TYPE_SDEI_CRITICAL,
__NR_STACK_TYPES
};
struct stack_info {
unsigned long low;
unsigned long high;
enum stack_type type;
};
/*
* A snapshot of a frame record or fp/lr register values, along with some
* accounting information necessary for robust unwinding.
*
* @fp: The fp value in the frame record (or the real fp)
* @pc: The fp value in the frame record (or the real lr)
*
* @stacks_done: Stacks which have been entirely unwound, for which it is no
* longer valid to unwind to.
*
* @prev_fp: The fp that pointed to this frame record, or a synthetic value
* of 0. This is used to ensure that within a stack, each
* subsequent frame record is at an increasing address.
* @prev_type: The type of stack this frame record was on, or a synthetic
* value of STACK_TYPE_UNKNOWN. This is used to detect a
* transition from one stack to another.
*
* @graph: When FUNCTION_GRAPH_TRACER is selected, holds the index of a
* replacement lr value in the ftrace graph stack.
*/
struct stackframe {
unsigned long fp;
unsigned long pc;
DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);
unsigned long prev_fp;
enum stack_type prev_type;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
int graph;
#endif
};
extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame);
extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
int (*fn)(struct stackframe *, void *), void *data);
extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
const char *loglvl);
DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
static inline bool on_stack(unsigned long sp, unsigned long low,
unsigned long high, enum stack_type type,
struct stack_info *info)
{
if (!low)
return false;
if (sp < low || sp >= high)
return false;
if (info) {
info->low = low;
info->high = high;
info->type = type;
}
return true;
}
static inline bool on_irq_stack(unsigned long sp,
struct stack_info *info)
{
unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr);
unsigned long high = low + IRQ_STACK_SIZE;
return on_stack(sp, low, high, STACK_TYPE_IRQ, info);
}
static inline bool on_task_stack(const struct task_struct *tsk,
unsigned long sp,
struct stack_info *info)
{
unsigned long low = (unsigned long)task_stack_page(tsk);
unsigned long high = low + THREAD_SIZE;
return on_stack(sp, low, high, STACK_TYPE_TASK, info);
}
#ifdef CONFIG_VMAP_STACK
DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack);
static inline bool on_overflow_stack(unsigned long sp,
struct stack_info *info)
{
unsigned long low = (unsigned long)raw_cpu_ptr(overflow_stack);
unsigned long high = low + OVERFLOW_STACK_SIZE;
return on_stack(sp, low, high, STACK_TYPE_OVERFLOW, info);
}
#else
static inline bool on_overflow_stack(unsigned long sp,
struct stack_info *info) { return false; }
#endif
/*
* We can only safely access per-cpu stacks from current in a non-preemptible
* context.
*/
static inline bool on_accessible_stack(const struct task_struct *tsk,
unsigned long sp,
struct stack_info *info)
{
if (info)
info->type = STACK_TYPE_UNKNOWN;
if (on_task_stack(tsk, sp, info))
return true;
if (tsk != current || preemptible())
return false;
if (on_irq_stack(sp, info))
return true;
if (on_overflow_stack(sp, info))
return true;
if (on_sdei_stack(sp, info))
return true;
return false;
}
static inline void start_backtrace(struct stackframe *frame,
unsigned long fp, unsigned long pc)
{
frame->fp = fp;
frame->pc = pc;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
frame->graph = 0;
#endif
/*
* Prime the first unwind.
*
* In unwind_frame() we'll check that the FP points to a valid stack,
* which can't be STACK_TYPE_UNKNOWN, and the first unwind will be
* treated as a transition to whichever stack that happens to be. The
* prev_fp value won't be used, but we set it to 0 such that it is
* definitely not an accessible stack address.
*/
bitmap_zero(frame->stacks_done, __NR_STACK_TYPES);
frame->prev_fp = 0;
frame->prev_type = STACK_TYPE_UNKNOWN;
}
#endif /* __ASM_STACKTRACE_H */
|
