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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> |
2d7c11bf | 21 | #include <asm/stacktrace.h> |
f16fb1ec RK |
22 | |
23 | static int report_trace(struct stackframe *frame, void *d) | |
24 | { | |
25 | unsigned int *depth = d; | |
26 | ||
27 | if (*depth) { | |
2d7c11bf | 28 | oprofile_add_trace(frame->pc); |
f16fb1ec RK |
29 | (*depth)--; |
30 | } | |
31 | ||
32 | return *depth == 0; | |
33 | } | |
fa0ebff6 RP |
34 | |
35 | /* | |
36 | * The registers we're interested in are at the end of the variable | |
37 | * length saved register structure. The fp points at the end of this | |
38 | * structure so the address of this struct is: | |
39 | * (struct frame_tail *)(xxx->fp)-1 | |
40 | */ | |
41 | struct frame_tail { | |
42 | struct frame_tail *fp; | |
43 | unsigned long sp; | |
44 | unsigned long lr; | |
45 | } __attribute__((packed)); | |
46 | ||
fa0ebff6 RP |
47 | static struct frame_tail* user_backtrace(struct frame_tail *tail) |
48 | { | |
c34d1b4d | 49 | struct frame_tail buftail[2]; |
fa0ebff6 | 50 | |
c34d1b4d HD |
51 | /* Also check accessibility of one struct frame_tail beyond */ |
52 | if (!access_ok(VERIFY_READ, tail, sizeof(buftail))) | |
53 | return NULL; | |
54 | if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail))) | |
fa0ebff6 RP |
55 | return NULL; |
56 | ||
c34d1b4d | 57 | oprofile_add_trace(buftail[0].lr); |
fa0ebff6 RP |
58 | |
59 | /* frame pointers should strictly progress back up the stack | |
60 | * (towards higher addresses) */ | |
c34d1b4d | 61 | if (tail >= buftail[0].fp) |
fa0ebff6 RP |
62 | return NULL; |
63 | ||
c34d1b4d | 64 | return buftail[0].fp-1; |
fa0ebff6 RP |
65 | } |
66 | ||
c013622d | 67 | void arm_backtrace(struct pt_regs * const regs, unsigned int depth) |
fa0ebff6 | 68 | { |
f16fb1ec | 69 | struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1; |
fa0ebff6 RP |
70 | |
71 | if (!user_mode(regs)) { | |
2d7c11bf CM |
72 | struct stackframe frame; |
73 | frame.fp = regs->ARM_fp; | |
74 | frame.sp = regs->ARM_sp; | |
75 | frame.lr = regs->ARM_lr; | |
76 | frame.pc = regs->ARM_pc; | |
77 | walk_stackframe(&frame, report_trace, &depth); | |
fa0ebff6 RP |
78 | return; |
79 | } | |
80 | ||
c34d1b4d | 81 | while (depth-- && tail && !((unsigned long) tail & 3)) |
fa0ebff6 | 82 | tail = user_backtrace(tail); |
fa0ebff6 | 83 | } |