1 /*
2 * Copyright (C) 2012 ARM Ltd.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program. If not, see <http://www.gnu.org/licenses/>.
15 */
16 #ifndef __ASM_STACKTRACE_H
17 #define __ASM_STACKTRACE_H
18
19 #include <linux/percpu.h>
20 #include <linux/sched.h>
21 #include <linux/sched/task_stack.h>
22
23 #include <asm/memory.h>
24 #include <asm/ptrace.h>
25 #include <asm/sdei.h>
26
27 struct stackframe {
28 unsigned long fp;
29 unsigned long pc;
30 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
31 int graph;
32 #endif
33 };
34
35 enum stack_type {
36 STACK_TYPE_UNKNOWN,
37 STACK_TYPE_TASK,
38 STACK_TYPE_IRQ,
39 STACK_TYPE_OVERFLOW,
40 STACK_TYPE_SDEI_NORMAL,
41 STACK_TYPE_SDEI_CRITICAL,
42 };
43
44 struct stack_info {
45 unsigned long low;
46 unsigned long high;
47 enum stack_type type;
48 };
49
50 extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame);
51 extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
52 int (*fn)(struct stackframe *, void *), void *data);
53 extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk);
54
55 DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
56
on_irq_stack(unsigned long sp,struct stack_info * info)57 static inline bool on_irq_stack(unsigned long sp,
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 if (!low)
64 return false;
65
66 if (sp < low || sp >= high)
67 return false;
68
69 if (info) {
70 info->low = low;
71 info->high = high;
72 info->type = STACK_TYPE_IRQ;
73 }
74
75 return true;
76 }
77
on_task_stack(struct task_struct * tsk,unsigned long sp,struct stack_info * info)78 static inline bool on_task_stack(struct task_struct *tsk, unsigned long sp,
79 struct stack_info *info)
80 {
81 unsigned long low = (unsigned long)task_stack_page(tsk);
82 unsigned long high = low + THREAD_SIZE;
83
84 if (sp < low || sp >= high)
85 return false;
86
87 if (info) {
88 info->low = low;
89 info->high = high;
90 info->type = STACK_TYPE_TASK;
91 }
92
93 return true;
94 }
95
96 #ifdef CONFIG_VMAP_STACK
97 DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack);
98
on_overflow_stack(unsigned long sp,struct stack_info * info)99 static inline bool on_overflow_stack(unsigned long sp,
100 struct stack_info *info)
101 {
102 unsigned long low = (unsigned long)raw_cpu_ptr(overflow_stack);
103 unsigned long high = low + OVERFLOW_STACK_SIZE;
104
105 if (sp < low || sp >= high)
106 return false;
107
108 if (info) {
109 info->low = low;
110 info->high = high;
111 info->type = STACK_TYPE_OVERFLOW;
112 }
113
114 return true;
115 }
116 #else
on_overflow_stack(unsigned long sp,struct stack_info * info)117 static inline bool on_overflow_stack(unsigned long sp,
118 struct stack_info *info) { return false; }
119 #endif
120
121
122 /*
123 * We can only safely access per-cpu stacks from current in a non-preemptible
124 * context.
125 */
on_accessible_stack(struct task_struct * tsk,unsigned long sp,struct stack_info * info)126 static inline bool on_accessible_stack(struct task_struct *tsk,
127 unsigned long sp,
128 struct stack_info *info)
129 {
130 if (on_task_stack(tsk, sp, info))
131 return true;
132 if (tsk != current || preemptible())
133 return false;
134 if (on_irq_stack(sp, info))
135 return true;
136 if (on_overflow_stack(sp, info))
137 return true;
138 if (on_sdei_stack(sp, info))
139 return true;
140
141 return false;
142 }
143
144 #endif /* __ASM_STACKTRACE_H */
145
