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fa0ebff6 RP |
1 | /* |
2 | * Arm specific backtracing code for oprofile | |
3 | * | |
4 | * Copyright 2005 Openedhand Ltd. | |
5 | * | |
6 | * Author: Richard Purdie <rpurdie@openedhand.com> | |
7 | * | |
8 | * Based on i386 oprofile backtrace code by John Levon, David Smith | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License version 2 as | |
12 | * published by the Free Software Foundation. | |
13 | * | |
14 | */ | |
15 | ||
16 | #include <linux/oprofile.h> | |
17 | #include <linux/sched.h> | |
18 | #include <linux/mm.h> | |
33fa9b13 | 19 | #include <linux/uaccess.h> |
fa0ebff6 | 20 | #include <asm/ptrace.h> |
fa0ebff6 | 21 | |
f16fb1ec RK |
22 | #include "../kernel/stacktrace.h" |
23 | ||
24 | static int report_trace(struct stackframe *frame, void *d) | |
25 | { | |
26 | unsigned int *depth = d; | |
27 | ||
28 | if (*depth) { | |
29 | oprofile_add_trace(frame->lr); | |
30 | (*depth)--; | |
31 | } | |
32 | ||
33 | return *depth == 0; | |
34 | } | |
fa0ebff6 RP |
35 | |
36 | /* | |
37 | * The registers we're interested in are at the end of the variable | |
38 | * length saved register structure. The fp points at the end of this | |
39 | * structure so the address of this struct is: | |
40 | * (struct frame_tail *)(xxx->fp)-1 | |
41 | */ | |
42 | struct frame_tail { | |
43 | struct frame_tail *fp; | |
44 | unsigned long sp; | |
45 | unsigned long lr; | |
46 | } __attribute__((packed)); | |
47 | ||
fa0ebff6 RP |
48 | static struct frame_tail* user_backtrace(struct frame_tail *tail) |
49 | { | |
c34d1b4d | 50 | struct frame_tail buftail[2]; |
fa0ebff6 | 51 | |
c34d1b4d HD |
52 | /* Also check accessibility of one struct frame_tail beyond */ |
53 | if (!access_ok(VERIFY_READ, tail, sizeof(buftail))) | |
54 | return NULL; | |
55 | if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail))) | |
fa0ebff6 RP |
56 | return NULL; |
57 | ||
c34d1b4d | 58 | oprofile_add_trace(buftail[0].lr); |
fa0ebff6 RP |
59 | |
60 | /* frame pointers should strictly progress back up the stack | |
61 | * (towards higher addresses) */ | |
c34d1b4d | 62 | if (tail >= buftail[0].fp) |
fa0ebff6 RP |
63 | return NULL; |
64 | ||
c34d1b4d | 65 | return buftail[0].fp-1; |
fa0ebff6 RP |
66 | } |
67 | ||
c013622d | 68 | void arm_backtrace(struct pt_regs * const regs, unsigned int depth) |
fa0ebff6 | 69 | { |
f16fb1ec | 70 | struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1; |
fa0ebff6 RP |
71 | |
72 | if (!user_mode(regs)) { | |
f16fb1ec RK |
73 | unsigned long base = ((unsigned long)regs) & ~(THREAD_SIZE - 1); |
74 | walk_stackframe(regs->ARM_fp, base, base + THREAD_SIZE, | |
75 | report_trace, &depth); | |
fa0ebff6 RP |
76 | return; |
77 | } | |
78 | ||
c34d1b4d | 79 | while (depth-- && tail && !((unsigned long) tail & 3)) |
fa0ebff6 | 80 | tail = user_backtrace(tail); |
fa0ebff6 | 81 | } |