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 
18 enum 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 
28 struct stack_info {
29 	unsigned long low;
30 	unsigned long high;
31 	enum stack_type type;
32 };
33 
34 extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
35 			   const char *loglvl);
36 
37 DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
38 
39 static inline bool on_stack(unsigned long sp, unsigned long size,
40 			    unsigned long low, unsigned long high,
41 			    enum stack_type type, struct stack_info *info)
42 {
43 	if (!low)
44 		return false;
45 
46 	if (sp < low || sp + size < sp || sp + size > high)
47 		return false;
48 
49 	if (info) {
50 		info->low = low;
51 		info->high = high;
52 		info->type = type;
53 	}
54 	return true;
55 }
56 
57 static inline bool on_irq_stack(unsigned long sp, unsigned long size,
58 				struct stack_info *info)
59 {
60 	unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr);
61 	unsigned long high = low + IRQ_STACK_SIZE;
62 
63 	return on_stack(sp, size, low, high, STACK_TYPE_IRQ, info);
64 }
65 
66 static inline bool on_task_stack(const struct task_struct *tsk,
67 				 unsigned long sp, unsigned long size,
68 				 struct stack_info *info)
69 {
70 	unsigned long low = (unsigned long)task_stack_page(tsk);
71 	unsigned long high = low + THREAD_SIZE;
72 
73 	return on_stack(sp, size, low, high, STACK_TYPE_TASK, info);
74 }
75 
76 #ifdef CONFIG_VMAP_STACK
77 DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack);
78 
79 static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
80 				struct stack_info *info)
81 {
82 	unsigned long low = (unsigned long)raw_cpu_ptr(overflow_stack);
83 	unsigned long high = low + OVERFLOW_STACK_SIZE;
84 
85 	return on_stack(sp, size, low, high, STACK_TYPE_OVERFLOW, info);
86 }
87 #else
88 static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
89 			struct stack_info *info) { return false; }
90 #endif
91 
92 
93 /*
94  * We can only safely access per-cpu stacks from current in a non-preemptible
95  * context.
96  */
97 static inline bool on_accessible_stack(const struct task_struct *tsk,
98 				       unsigned long sp, unsigned long size,
99 				       struct stack_info *info)
100 {
101 	if (info)
102 		info->type = STACK_TYPE_UNKNOWN;
103 
104 	if (on_task_stack(tsk, sp, size, info))
105 		return true;
106 	if (tsk != current || preemptible())
107 		return false;
108 	if (on_irq_stack(sp, size, info))
109 		return true;
110 	if (on_overflow_stack(sp, size, info))
111 		return true;
112 	if (on_sdei_stack(sp, size, info))
113 		return true;
114 
115 	return false;
116 }
117 
118 #endif	/* __ASM_STACKTRACE_H */
119