1*4882a593Smuzhiyun /**
2*4882a593Smuzhiyun * @file backtrace.c
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun * @remark Copyright 2002 OProfile authors
5*4882a593Smuzhiyun * @remark Read the file COPYING
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * @author John Levon
8*4882a593Smuzhiyun * @author David Smith
9*4882a593Smuzhiyun */
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun #include <linux/oprofile.h>
12*4882a593Smuzhiyun #include <linux/sched.h>
13*4882a593Smuzhiyun #include <linux/mm.h>
14*4882a593Smuzhiyun #include <linux/compat.h>
15*4882a593Smuzhiyun #include <linux/uaccess.h>
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun #include <asm/ptrace.h>
18*4882a593Smuzhiyun #include <asm/stacktrace.h>
19*4882a593Smuzhiyun #include <asm/unwind.h>
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun #ifdef CONFIG_COMPAT
22*4882a593Smuzhiyun static struct stack_frame_ia32 *
dump_user_backtrace_32(struct stack_frame_ia32 * head)23*4882a593Smuzhiyun dump_user_backtrace_32(struct stack_frame_ia32 *head)
24*4882a593Smuzhiyun {
25*4882a593Smuzhiyun /* Also check accessibility of one struct frame_head beyond: */
26*4882a593Smuzhiyun struct stack_frame_ia32 bufhead[2];
27*4882a593Smuzhiyun struct stack_frame_ia32 *fp;
28*4882a593Smuzhiyun unsigned long bytes;
29*4882a593Smuzhiyun
30*4882a593Smuzhiyun bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
31*4882a593Smuzhiyun if (bytes != 0)
32*4882a593Smuzhiyun return NULL;
33*4882a593Smuzhiyun
34*4882a593Smuzhiyun fp = (struct stack_frame_ia32 *) compat_ptr(bufhead[0].next_frame);
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun oprofile_add_trace(bufhead[0].return_address);
37*4882a593Smuzhiyun
38*4882a593Smuzhiyun /* frame pointers should strictly progress back up the stack
39*4882a593Smuzhiyun * (towards higher addresses) */
40*4882a593Smuzhiyun if (head >= fp)
41*4882a593Smuzhiyun return NULL;
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun return fp;
44*4882a593Smuzhiyun }
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun static inline int
x86_backtrace_32(struct pt_regs * const regs,unsigned int depth)47*4882a593Smuzhiyun x86_backtrace_32(struct pt_regs * const regs, unsigned int depth)
48*4882a593Smuzhiyun {
49*4882a593Smuzhiyun struct stack_frame_ia32 *head;
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun /* User process is IA32 */
52*4882a593Smuzhiyun if (!current || !test_thread_flag(TIF_IA32))
53*4882a593Smuzhiyun return 0;
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun head = (struct stack_frame_ia32 *) regs->bp;
56*4882a593Smuzhiyun while (depth-- && head)
57*4882a593Smuzhiyun head = dump_user_backtrace_32(head);
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun return 1;
60*4882a593Smuzhiyun }
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun #else
63*4882a593Smuzhiyun static inline int
x86_backtrace_32(struct pt_regs * const regs,unsigned int depth)64*4882a593Smuzhiyun x86_backtrace_32(struct pt_regs * const regs, unsigned int depth)
65*4882a593Smuzhiyun {
66*4882a593Smuzhiyun return 0;
67*4882a593Smuzhiyun }
68*4882a593Smuzhiyun #endif /* CONFIG_COMPAT */
69*4882a593Smuzhiyun
dump_user_backtrace(struct stack_frame * head)70*4882a593Smuzhiyun static struct stack_frame *dump_user_backtrace(struct stack_frame *head)
71*4882a593Smuzhiyun {
72*4882a593Smuzhiyun /* Also check accessibility of one struct frame_head beyond: */
73*4882a593Smuzhiyun struct stack_frame bufhead[2];
74*4882a593Smuzhiyun unsigned long bytes;
75*4882a593Smuzhiyun
76*4882a593Smuzhiyun bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
77*4882a593Smuzhiyun if (bytes != 0)
78*4882a593Smuzhiyun return NULL;
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun oprofile_add_trace(bufhead[0].return_address);
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun /* frame pointers should strictly progress back up the stack
83*4882a593Smuzhiyun * (towards higher addresses) */
84*4882a593Smuzhiyun if (head >= bufhead[0].next_frame)
85*4882a593Smuzhiyun return NULL;
86*4882a593Smuzhiyun
87*4882a593Smuzhiyun return bufhead[0].next_frame;
88*4882a593Smuzhiyun }
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun void
x86_backtrace(struct pt_regs * const regs,unsigned int depth)91*4882a593Smuzhiyun x86_backtrace(struct pt_regs * const regs, unsigned int depth)
92*4882a593Smuzhiyun {
93*4882a593Smuzhiyun struct stack_frame *head = (struct stack_frame *)frame_pointer(regs);
94*4882a593Smuzhiyun
95*4882a593Smuzhiyun if (!user_mode(regs)) {
96*4882a593Smuzhiyun struct unwind_state state;
97*4882a593Smuzhiyun unsigned long addr;
98*4882a593Smuzhiyun
99*4882a593Smuzhiyun if (!depth)
100*4882a593Smuzhiyun return;
101*4882a593Smuzhiyun
102*4882a593Smuzhiyun oprofile_add_trace(regs->ip);
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun if (!--depth)
105*4882a593Smuzhiyun return;
106*4882a593Smuzhiyun
107*4882a593Smuzhiyun for (unwind_start(&state, current, regs, NULL);
108*4882a593Smuzhiyun !unwind_done(&state); unwind_next_frame(&state)) {
109*4882a593Smuzhiyun addr = unwind_get_return_address(&state);
110*4882a593Smuzhiyun if (!addr)
111*4882a593Smuzhiyun break;
112*4882a593Smuzhiyun
113*4882a593Smuzhiyun oprofile_add_trace(addr);
114*4882a593Smuzhiyun
115*4882a593Smuzhiyun if (!--depth)
116*4882a593Smuzhiyun break;
117*4882a593Smuzhiyun }
118*4882a593Smuzhiyun
119*4882a593Smuzhiyun return;
120*4882a593Smuzhiyun }
121*4882a593Smuzhiyun
122*4882a593Smuzhiyun if (x86_backtrace_32(regs, depth))
123*4882a593Smuzhiyun return;
124*4882a593Smuzhiyun
125*4882a593Smuzhiyun while (depth-- && head)
126*4882a593Smuzhiyun head = dump_user_backtrace(head);
127*4882a593Smuzhiyun }
128