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 extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame);
36 extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
37 			    int (*fn)(struct stackframe *, void *), void *data);
38 extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk);
39 
40 DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
41 
42 static inline bool on_irq_stack(unsigned long sp)
43 {
44 	unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr);
45 	unsigned long high = low + IRQ_STACK_SIZE;
46 
47 	if (!low)
48 		return false;
49 
50 	return (low <= sp && sp < high);
51 }
52 
53 static inline bool on_task_stack(struct task_struct *tsk, unsigned long sp)
54 {
55 	unsigned long low = (unsigned long)task_stack_page(tsk);
56 	unsigned long high = low + THREAD_SIZE;
57 
58 	return (low <= sp && sp < high);
59 }
60 
61 #ifdef CONFIG_VMAP_STACK
62 DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack);
63 
64 static inline bool on_overflow_stack(unsigned long sp)
65 {
66 	unsigned long low = (unsigned long)raw_cpu_ptr(overflow_stack);
67 	unsigned long high = low + OVERFLOW_STACK_SIZE;
68 
69 	return (low <= sp && sp < high);
70 }
71 #else
72 static inline bool on_overflow_stack(unsigned long sp) { return false; }
73 #endif
74 
75 /*
76  * We can only safely access per-cpu stacks from current in a non-preemptible
77  * context.
78  */
79 static inline bool on_accessible_stack(struct task_struct *tsk, unsigned long sp)
80 {
81 	if (on_task_stack(tsk, sp))
82 		return true;
83 	if (tsk != current || preemptible())
84 		return false;
85 	if (on_irq_stack(sp))
86 		return true;
87 	if (on_overflow_stack(sp))
88 		return true;
89 	if (on_sdei_stack(sp))
90 		return true;
91 
92 	return false;
93 }
94 
95 #endif	/* __ASM_STACKTRACE_H */
96