Merge tag 'linux-kselftest-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6-block.git] / arch / xtensa / kernel / stacktrace.c
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1/*
2 * arch/xtensa/kernel/stacktrace.c
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 2001 - 2013 Tensilica Inc.
9 */
10#include <linux/export.h>
11#include <linux/sched.h>
12#include <linux/stacktrace.h>
13
14#include <asm/stacktrace.h>
15#include <asm/traps.h>
16
17void walk_stackframe(unsigned long *sp,
18 int (*fn)(struct stackframe *frame, void *data),
19 void *data)
20{
21 unsigned long a0, a1;
22 unsigned long sp_end;
23
24 a1 = (unsigned long)sp;
25 sp_end = ALIGN(a1, THREAD_SIZE);
26
27 spill_registers();
28
29 while (a1 < sp_end) {
30 struct stackframe frame;
31
32 sp = (unsigned long *)a1;
33
34 a0 = *(sp - 4);
35 a1 = *(sp - 3);
36
37 if (a1 <= (unsigned long)sp)
38 break;
39
40 frame.pc = MAKE_PC_FROM_RA(a0, a1);
41 frame.sp = a1;
42
43 if (fn(&frame, data))
44 return;
45 }
46}
47
48#ifdef CONFIG_STACKTRACE
49
50struct stack_trace_data {
51 struct stack_trace *trace;
52 unsigned skip;
53};
54
55static int stack_trace_cb(struct stackframe *frame, void *data)
56{
57 struct stack_trace_data *trace_data = data;
58 struct stack_trace *trace = trace_data->trace;
59
60 if (trace_data->skip) {
61 --trace_data->skip;
62 return 0;
63 }
64 if (!kernel_text_address(frame->pc))
65 return 0;
66
67 trace->entries[trace->nr_entries++] = frame->pc;
68 return trace->nr_entries >= trace->max_entries;
69}
70
71void save_stack_trace_tsk(struct task_struct *task, struct stack_trace *trace)
72{
73 struct stack_trace_data trace_data = {
74 .trace = trace,
75 .skip = trace->skip,
76 };
77 walk_stackframe(stack_pointer(task), stack_trace_cb, &trace_data);
78}
79EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
80
81void save_stack_trace(struct stack_trace *trace)
82{
83 save_stack_trace_tsk(current, trace);
84}
85EXPORT_SYMBOL_GPL(save_stack_trace);
86
87#endif
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88
89#ifdef CONFIG_FRAME_POINTER
90
91struct return_addr_data {
92 unsigned long addr;
93 unsigned skip;
94};
95
96static int return_address_cb(struct stackframe *frame, void *data)
97{
98 struct return_addr_data *r = data;
99
100 if (r->skip) {
101 --r->skip;
102 return 0;
103 }
104 if (!kernel_text_address(frame->pc))
105 return 0;
106 r->addr = frame->pc;
107 return 1;
108}
109
110unsigned long return_address(unsigned level)
111{
112 struct return_addr_data r = {
113 .skip = level + 1,
114 };
115 walk_stackframe(stack_pointer(NULL), return_address_cb, &r);
116 return r.addr;
117}
118EXPORT_SYMBOL(return_address);
119
120#endif