1#include <linux/sched.h>
 2#include <linux/stacktrace.h>
 3#include <linux/stacktrace.h>
 4#include <asm/stacktrace.h>
 5
 6void walk_stackframe(unsigned long sp,
 7		     int (*fn)(unsigned long addr, void *data),
 8		     void *data)
 9{
10	unsigned long high = ALIGN(sp, THREAD_SIZE);
11
12	for (; sp <= high - 4; sp += 4) {
13		unsigned long addr = *(unsigned long *) sp;
14
15		if (!kernel_text_address(addr))
16			continue;
17
18		if (fn(addr, data))
19			break;
20	}
21}
22
23struct stack_trace_data {
24	struct stack_trace *trace;
25	unsigned int no_sched_functions;
26	unsigned int skip;
27};
28
29#ifdef CONFIG_STACKTRACE
30
31static int save_trace(unsigned long addr, void *d)
32{
33	struct stack_trace_data *data = d;
34	struct stack_trace *trace = data->trace;
35
36	if (data->no_sched_functions && in_sched_functions(addr))
37		return 0;
38
39	if (data->skip) {
40		data->skip--;
41		return 0;
42	}
43
44	trace->entries[trace->nr_entries++] = addr;
45
46	return trace->nr_entries >= trace->max_entries;
47}
48
49void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
50{
51	struct stack_trace_data data;
52	unsigned long sp;
53
54	data.trace = trace;
55	data.skip = trace->skip;
56
57	if (tsk != current) {
58		data.no_sched_functions = 1;
59		sp = tsk->thread.ksp;
60	} else {
61		data.no_sched_functions = 0;
62		sp = rdsp();
63	}
64
65	walk_stackframe(sp, save_trace, &data);
66	if (trace->nr_entries < trace->max_entries)
67		trace->entries[trace->nr_entries++] = ULONG_MAX;
68}
69
70void save_stack_trace(struct stack_trace *trace)
71{
72	save_stack_trace_tsk(current, trace);
73}
74EXPORT_SYMBOL_GPL(save_stack_trace);
75
76#endif /* CONFIG_STACKTRACE */