1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __LINUX_STACKTRACE_H
3 #define __LINUX_STACKTRACE_H
4 
5 #include <linux/types.h>
6 #include <asm/errno.h>
7 
8 struct task_struct;
9 struct pt_regs;
10 
11 #ifdef CONFIG_ARCH_STACKWALK
12 
13 /**
14  * stack_trace_consume_fn - Callback for arch_stack_walk()
15  * @cookie:	Caller supplied pointer handed back by arch_stack_walk()
16  * @addr:	The stack entry address to consume
17  *
18  * Return:	True, if the entry was consumed or skipped
19  *		False, if there is no space left to store
20  */
21 typedef bool (*stack_trace_consume_fn)(void *cookie, unsigned long addr);
22 /**
23  * arch_stack_walk - Architecture specific function to walk the stack
24  * @consume_entry:	Callback which is invoked by the architecture code for
25  *			each entry.
26  * @cookie:		Caller supplied pointer which is handed back to
27  *			@consume_entry
28  * @task:		Pointer to a task struct, can be NULL
29  * @regs:		Pointer to registers, can be NULL
30  *
31  * ============ ======= ============================================
32  * task	        regs
33  * ============ ======= ============================================
34  * task		NULL	Stack trace from task (can be current)
35  * current	regs	Stack trace starting on regs->stackpointer
36  * ============ ======= ============================================
37  */
38 void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
39 		     struct task_struct *task, struct pt_regs *regs);
40 
41 /**
42  * arch_stack_walk_reliable - Architecture specific function to walk the
43  *			      stack reliably
44  *
45  * @consume_entry:	Callback which is invoked by the architecture code for
46  *			each entry.
47  * @cookie:		Caller supplied pointer which is handed back to
48  *			@consume_entry
49  * @task:		Pointer to a task struct, can be NULL
50  *
51  * This function returns an error if it detects any unreliable
52  * features of the stack. Otherwise it guarantees that the stack
53  * trace is reliable.
54  *
55  * If the task is not 'current', the caller *must* ensure the task is
56  * inactive and its stack is pinned.
57  */
58 int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry, void *cookie,
59 			     struct task_struct *task);
60 
61 void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
62 			  const struct pt_regs *regs);
63 #endif /* CONFIG_ARCH_STACKWALK */
64 
65 #ifdef CONFIG_STACKTRACE
66 void stack_trace_print(const unsigned long *trace, unsigned int nr_entries,
67 		       int spaces);
68 int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries,
69 			unsigned int nr_entries, int spaces);
70 unsigned int stack_trace_save(unsigned long *store, unsigned int size,
71 			      unsigned int skipnr);
72 unsigned int stack_trace_save_tsk(struct task_struct *task,
73 				  unsigned long *store, unsigned int size,
74 				  unsigned int skipnr);
75 unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
76 				   unsigned int size, unsigned int skipnr);
77 unsigned int stack_trace_save_user(unsigned long *store, unsigned int size);
78 unsigned int filter_irq_stacks(unsigned long *entries, unsigned int nr_entries);
79 
80 #ifndef CONFIG_ARCH_STACKWALK
81 /* Internal interfaces. Do not use in generic code */
82 struct stack_trace {
83 	unsigned int nr_entries, max_entries;
84 	unsigned long *entries;
85 	unsigned int skip;	/* input argument: How many entries to skip */
86 };
87 
88 extern void save_stack_trace(struct stack_trace *trace);
89 extern void save_stack_trace_regs(struct pt_regs *regs,
90 				  struct stack_trace *trace);
91 extern void save_stack_trace_tsk(struct task_struct *tsk,
92 				struct stack_trace *trace);
93 extern int save_stack_trace_tsk_reliable(struct task_struct *tsk,
94 					 struct stack_trace *trace);
95 extern void save_stack_trace_user(struct stack_trace *trace);
96 #endif /* !CONFIG_ARCH_STACKWALK */
97 #endif /* CONFIG_STACKTRACE */
98 
99 #if defined(CONFIG_STACKTRACE) && defined(CONFIG_HAVE_RELIABLE_STACKTRACE)
100 int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
101 				  unsigned int size);
102 #else
stack_trace_save_tsk_reliable(struct task_struct * tsk,unsigned long * store,unsigned int size)103 static inline int stack_trace_save_tsk_reliable(struct task_struct *tsk,
104 						unsigned long *store,
105 						unsigned int size)
106 {
107 	return -ENOSYS;
108 }
109 #endif
110 
111 #endif /* __LINUX_STACKTRACE_H */
112