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 <asm/ptrace.h>
15 #include <asm/uaccess.h>
16 #include <asm/stacktrace.h>
17 #include <linux/compat.h>
18
backtrace_warning_symbol(void * data,char * msg,unsigned long symbol)19 static void backtrace_warning_symbol(void *data, char *msg,
20 unsigned long symbol)
21 {
22 /* Ignore warnings */
23 }
24
backtrace_warning(void * data,char * msg)25 static void backtrace_warning(void *data, char *msg)
26 {
27 /* Ignore warnings */
28 }
29
backtrace_stack(void * data,char * name)30 static int backtrace_stack(void *data, char *name)
31 {
32 /* Yes, we want all stacks */
33 return 0;
34 }
35
backtrace_address(void * data,unsigned long addr,int reliable)36 static void backtrace_address(void *data, unsigned long addr, int reliable)
37 {
38 unsigned int *depth = data;
39
40 if ((*depth)--)
41 oprofile_add_trace(addr);
42 }
43
44 static struct stacktrace_ops backtrace_ops = {
45 .warning = backtrace_warning,
46 .warning_symbol = backtrace_warning_symbol,
47 .stack = backtrace_stack,
48 .address = backtrace_address,
49 .walk_stack = print_context_stack,
50 };
51
52 #ifdef CONFIG_COMPAT
53 static struct stack_frame_ia32 *
dump_user_backtrace_32(struct stack_frame_ia32 * head)54 dump_user_backtrace_32(struct stack_frame_ia32 *head)
55 {
56 struct stack_frame_ia32 bufhead[2];
57 struct stack_frame_ia32 *fp;
58
59 /* Also check accessibility of one struct frame_head beyond */
60 if (!access_ok(VERIFY_READ, head, sizeof(bufhead)))
61 return NULL;
62 if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead)))
63 return NULL;
64
65 fp = (struct stack_frame_ia32 *) compat_ptr(bufhead[0].next_frame);
66
67 oprofile_add_trace(bufhead[0].return_address);
68
69 /* frame pointers should strictly progress back up the stack
70 * (towards higher addresses) */
71 if (head >= fp)
72 return NULL;
73
74 return fp;
75 }
76
77 static inline int
x86_backtrace_32(struct pt_regs * const regs,unsigned int depth)78 x86_backtrace_32(struct pt_regs * const regs, unsigned int depth)
79 {
80 struct stack_frame_ia32 *head;
81
82 /* User process is 32-bit */
83 if (!current || !test_thread_flag(TIF_IA32))
84 return 0;
85
86 head = (struct stack_frame_ia32 *) regs->bp;
87 while (depth-- && head)
88 head = dump_user_backtrace_32(head);
89
90 return 1;
91 }
92
93 #else
94 static inline int
x86_backtrace_32(struct pt_regs * const regs,unsigned int depth)95 x86_backtrace_32(struct pt_regs * const regs, unsigned int depth)
96 {
97 return 0;
98 }
99 #endif /* CONFIG_COMPAT */
100
dump_user_backtrace(struct stack_frame * head)101 static struct stack_frame *dump_user_backtrace(struct stack_frame *head)
102 {
103 struct stack_frame bufhead[2];
104
105 /* Also check accessibility of one struct stack_frame beyond */
106 if (!access_ok(VERIFY_READ, head, sizeof(bufhead)))
107 return NULL;
108 if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead)))
109 return NULL;
110
111 oprofile_add_trace(bufhead[0].return_address);
112
113 /* frame pointers should strictly progress back up the stack
114 * (towards higher addresses) */
115 if (head >= bufhead[0].next_frame)
116 return NULL;
117
118 return bufhead[0].next_frame;
119 }
120
121 void
x86_backtrace(struct pt_regs * const regs,unsigned int depth)122 x86_backtrace(struct pt_regs * const regs, unsigned int depth)
123 {
124 struct stack_frame *head = (struct stack_frame *)frame_pointer(regs);
125
126 if (!user_mode_vm(regs)) {
127 unsigned long stack = kernel_stack_pointer(regs);
128 if (depth)
129 dump_trace(NULL, regs, (unsigned long *)stack, 0,
130 &backtrace_ops, &depth);
131 return;
132 }
133
134 if (x86_backtrace_32(regs, depth))
135 return;
136
137 while (depth-- && head)
138 head = dump_user_backtrace(head);
139 }
140