1 /**
2 * @file backtrace.c
3 *
4 * @remark Copyright 2002 OProfile authors
5 * @remark Read the file COPYING
6 *
7 * @author John Levon
8 * @author David Smith
9 */
10
11 #include <linux/oprofile.h>
12 #include <linux/sched.h>
13 #include <linux/mm.h>
14 #include <linux/compat.h>
15 #include <linux/uaccess.h>
16
17 #include <asm/ptrace.h>
18 #include <asm/stacktrace.h>
19 #include <asm/unwind.h>
20
21 #ifdef CONFIG_COMPAT
22 static struct stack_frame_ia32 *
dump_user_backtrace_32(struct stack_frame_ia32 * head)23 dump_user_backtrace_32(struct stack_frame_ia32 *head)
24 {
25 /* Also check accessibility of one struct frame_head beyond: */
26 struct stack_frame_ia32 bufhead[2];
27 struct stack_frame_ia32 *fp;
28 unsigned long bytes;
29
30 bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
31 if (bytes != 0)
32 return NULL;
33
34 fp = (struct stack_frame_ia32 *) compat_ptr(bufhead[0].next_frame);
35
36 oprofile_add_trace(bufhead[0].return_address);
37
38 /* frame pointers should strictly progress back up the stack
39 * (towards higher addresses) */
40 if (head >= fp)
41 return NULL;
42
43 return fp;
44 }
45
46 static inline int
x86_backtrace_32(struct pt_regs * const regs,unsigned int depth)47 x86_backtrace_32(struct pt_regs * const regs, unsigned int depth)
48 {
49 struct stack_frame_ia32 *head;
50
51 /* User process is IA32 */
52 if (!current || !test_thread_flag(TIF_IA32))
53 return 0;
54
55 head = (struct stack_frame_ia32 *) regs->bp;
56 while (depth-- && head)
57 head = dump_user_backtrace_32(head);
58
59 return 1;
60 }
61
62 #else
63 static inline int
x86_backtrace_32(struct pt_regs * const regs,unsigned int depth)64 x86_backtrace_32(struct pt_regs * const regs, unsigned int depth)
65 {
66 return 0;
67 }
68 #endif /* CONFIG_COMPAT */
69
dump_user_backtrace(struct stack_frame * head)70 static struct stack_frame *dump_user_backtrace(struct stack_frame *head)
71 {
72 /* Also check accessibility of one struct frame_head beyond: */
73 struct stack_frame bufhead[2];
74 unsigned long bytes;
75
76 bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
77 if (bytes != 0)
78 return NULL;
79
80 oprofile_add_trace(bufhead[0].return_address);
81
82 /* frame pointers should strictly progress back up the stack
83 * (towards higher addresses) */
84 if (head >= bufhead[0].next_frame)
85 return NULL;
86
87 return bufhead[0].next_frame;
88 }
89
90 void
x86_backtrace(struct pt_regs * const regs,unsigned int depth)91 x86_backtrace(struct pt_regs * const regs, unsigned int depth)
92 {
93 struct stack_frame *head = (struct stack_frame *)frame_pointer(regs);
94
95 if (!user_mode(regs)) {
96 struct unwind_state state;
97 unsigned long addr;
98
99 if (!depth)
100 return;
101
102 oprofile_add_trace(regs->ip);
103
104 if (!--depth)
105 return;
106
107 for (unwind_start(&state, current, regs, NULL);
108 !unwind_done(&state); unwind_next_frame(&state)) {
109 addr = unwind_get_return_address(&state);
110 if (!addr)
111 break;
112
113 oprofile_add_trace(addr);
114
115 if (!--depth)
116 break;
117 }
118
119 return;
120 }
121
122 if (x86_backtrace_32(regs, depth))
123 return;
124
125 while (depth-- && head)
126 head = dump_user_backtrace(head);
127 }
128