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 * @graph: When FUNCTION_GRAPH_TRACER is selected, holds the index of a
52 * replacement lr value in the ftrace graph stack.
53 */
54struct stackframe {
55 unsigned long fp;
56 unsigned long pc;
57 DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);
58 unsigned long prev_fp;
59 enum stack_type prev_type;
60#ifdef CONFIG_FUNCTION_GRAPH_TRACER
61 int graph;
62#endif
63#ifdef CONFIG_KRETPROBES
64 struct llist_node *kr_cur;
65#endif
66};
67
68extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame);
69extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
70 bool (*fn)(void *, unsigned long), void *data);
71extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
72 const char *loglvl);
73
74DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
75
76static inline bool on_stack(unsigned long sp, unsigned long size,
77 unsigned long low, unsigned long high,
78 enum stack_type type, struct stack_info *info)
79{
80 if (!low)
81 return false;
82
83 if (sp < low || sp + size < sp || sp + size > high)
84 return false;
85
86 if (info) {
87 info->low = low;
88 info->high = high;
89 info->type = type;
90 }
91 return true;
92}
93
94static inline bool on_irq_stack(unsigned long sp, unsigned long size,
95 struct stack_info *info)
96{
97 unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr);
98 unsigned long high = low + IRQ_STACK_SIZE;
99
100 return on_stack(sp, size, low, high, STACK_TYPE_IRQ, info);
101}
102
103static inline bool on_task_stack(const struct task_struct *tsk,
104 unsigned long sp, unsigned long size,
105 struct stack_info *info)
106{
107 unsigned long low = (unsigned long)task_stack_page(tsk);
108 unsigned long high = low + THREAD_SIZE;
109
110 return on_stack(sp, size, low, high, STACK_TYPE_TASK, info);
111}
112
113#ifdef CONFIG_VMAP_STACK
114DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack);
115
116static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
117 struct stack_info *info)
118{
119 unsigned long low = (unsigned long)raw_cpu_ptr(overflow_stack);
120 unsigned long high = low + OVERFLOW_STACK_SIZE;
121
122 return on_stack(sp, size, low, high, STACK_TYPE_OVERFLOW, info);
123}
124#else
125static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
126 struct stack_info *info) { return false; }
127#endif
128
129
130/*
131 * We can only safely access per-cpu stacks from current in a non-preemptible
132 * context.
133 */
134static inline bool on_accessible_stack(const struct task_struct *tsk,
135 unsigned long sp, unsigned long size,
136 struct stack_info *info)
137{
138 if (info)
139 info->type = STACK_TYPE_UNKNOWN;
140
141 if (on_task_stack(tsk, sp, size, info))
142 return true;
143 if (tsk != current || preemptible())
144 return false;
145 if (on_irq_stack(sp, size, info))
146 return true;
147 if (on_overflow_stack(sp, size, info))
148 return true;
149 if (on_sdei_stack(sp, size, info))
150 return true;
151
152 return false;
153}
154
155void start_backtrace(struct stackframe *frame, unsigned long fp,
156 unsigned long pc);
157
158#endif /* __ASM_STACKTRACE_H */