Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2012 ARM Ltd.
4 */
5#ifndef __ASM_STACKTRACE_H
6#define __ASM_STACKTRACE_H
7
8#include <linux/percpu.h>
9#include <linux/sched.h>
10#include <linux/sched/task_stack.h>
11#include <linux/types.h>
12#include <linux/llist.h>
13
14#include <asm/memory.h>
15#include <asm/ptrace.h>
16#include <asm/sdei.h>
17
18enum stack_type {
19 STACK_TYPE_UNKNOWN,
20 STACK_TYPE_TASK,
21 STACK_TYPE_IRQ,
22 STACK_TYPE_OVERFLOW,
23 STACK_TYPE_SDEI_NORMAL,
24 STACK_TYPE_SDEI_CRITICAL,
25 __NR_STACK_TYPES
26};
27
28struct stack_info {
29 unsigned long low;
30 unsigned long high;
31 enum stack_type type;
32};
33
34/*
35 * A snapshot of a frame record or fp/lr register values, along with some
36 * accounting information necessary for robust unwinding.
37 *
38 * @fp: The fp value in the frame record (or the real fp)
39 * @pc: The lr value in the frame record (or the real lr)
40 *
41 * @stacks_done: Stacks which have been entirely unwound, for which it is no
42 * longer valid to unwind to.
43 *
44 * @prev_fp: The fp that pointed to this frame record, or a synthetic value
45 * of 0. This is used to ensure that within a stack, each
46 * subsequent frame record is at an increasing address.
47 * @prev_type: The type of stack this frame record was on, or a synthetic
48 * value of STACK_TYPE_UNKNOWN. This is used to detect a
49 * transition from one stack to another.
50 *
51 * @kr_cur: When KRETPROBES is selected, holds the kretprobe instance
52 * associated with the most recently encountered replacement lr
53 * value.
54 */
55struct stackframe {
56 unsigned long fp;
57 unsigned long pc;
58 DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);
59 unsigned long prev_fp;
60 enum stack_type prev_type;
61#ifdef CONFIG_KRETPROBES
62 struct llist_node *kr_cur;
63#endif
64};
65
66extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
67 const char *loglvl);
68
69DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
70
71static inline bool on_stack(unsigned long sp, unsigned long size,
72 unsigned long low, unsigned long high,
73 enum stack_type type, struct stack_info *info)
74{
75 if (!low)
76 return false;
77
78 if (sp < low || sp + size < sp || sp + size > high)
79 return false;
80
81 if (info) {
82 info->low = low;
83 info->high = high;
84 info->type = type;
85 }
86 return true;
87}
88
89static inline bool on_irq_stack(unsigned long sp, unsigned long size,
90 struct stack_info *info)
91{
92 unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr);
93 unsigned long high = low + IRQ_STACK_SIZE;
94
95 return on_stack(sp, size, low, high, STACK_TYPE_IRQ, info);
96}
97
98static inline bool on_task_stack(const struct task_struct *tsk,
99 unsigned long sp, unsigned long size,
100 struct stack_info *info)
101{
102 unsigned long low = (unsigned long)task_stack_page(tsk);
103 unsigned long high = low + THREAD_SIZE;
104
105 return on_stack(sp, size, low, high, STACK_TYPE_TASK, info);
106}
107
108#ifdef CONFIG_VMAP_STACK
109DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack);
110
111static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
112 struct stack_info *info)
113{
114 unsigned long low = (unsigned long)raw_cpu_ptr(overflow_stack);
115 unsigned long high = low + OVERFLOW_STACK_SIZE;
116
117 return on_stack(sp, size, low, high, STACK_TYPE_OVERFLOW, info);
118}
119#else
120static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
121 struct stack_info *info) { return false; }
122#endif
123
124
125/*
126 * We can only safely access per-cpu stacks from current in a non-preemptible
127 * context.
128 */
129static inline bool on_accessible_stack(const struct task_struct *tsk,
130 unsigned long sp, unsigned long size,
131 struct stack_info *info)
132{
133 if (info)
134 info->type = STACK_TYPE_UNKNOWN;
135
136 if (on_task_stack(tsk, sp, size, info))
137 return true;
138 if (tsk != current || preemptible())
139 return false;
140 if (on_irq_stack(sp, size, info))
141 return true;
142 if (on_overflow_stack(sp, size, info))
143 return true;
144 if (on_sdei_stack(sp, size, info))
145 return true;
146
147 return false;
148}
149
150#endif /* __ASM_STACKTRACE_H */