diff options
Diffstat (limited to 'arch/avr32/oprofile/backtrace.c')
-rw-r--r-- | arch/avr32/oprofile/backtrace.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/arch/avr32/oprofile/backtrace.c b/arch/avr32/oprofile/backtrace.c new file mode 100644 index 000000000000..75d9ad6f99cf --- /dev/null +++ b/arch/avr32/oprofile/backtrace.c | |||
@@ -0,0 +1,81 @@ | |||
1 | /* | ||
2 | * AVR32 specific backtracing code for oprofile | ||
3 | * | ||
4 | * Copyright 2008 Weinmann GmbH | ||
5 | * | ||
6 | * Author: Nikolaus Voss <n.voss@weinmann.de> | ||
7 | * | ||
8 | * Based on i386 oprofile backtrace code by John Levon and 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/uaccess.h> | ||
19 | |||
20 | /* The first two words of each frame on the stack look like this if we have | ||
21 | * frame pointers */ | ||
22 | struct frame_head { | ||
23 | unsigned long lr; | ||
24 | struct frame_head *fp; | ||
25 | }; | ||
26 | |||
27 | /* copied from arch/avr32/kernel/process.c */ | ||
28 | static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p) | ||
29 | { | ||
30 | return (p > (unsigned long)tinfo) | ||
31 | && (p < (unsigned long)tinfo + THREAD_SIZE - 3); | ||
32 | } | ||
33 | |||
34 | /* copied from arch/x86/oprofile/backtrace.c */ | ||
35 | static struct frame_head *dump_user_backtrace(struct frame_head *head) | ||
36 | { | ||
37 | struct frame_head bufhead[2]; | ||
38 | |||
39 | /* Also check accessibility of one struct frame_head beyond */ | ||
40 | if (!access_ok(VERIFY_READ, head, sizeof(bufhead))) | ||
41 | return NULL; | ||
42 | if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead))) | ||
43 | return NULL; | ||
44 | |||
45 | oprofile_add_trace(bufhead[0].lr); | ||
46 | |||
47 | /* frame pointers should strictly progress back up the stack | ||
48 | * (towards higher addresses) */ | ||
49 | if (bufhead[0].fp <= head) | ||
50 | return NULL; | ||
51 | |||
52 | return bufhead[0].fp; | ||
53 | } | ||
54 | |||
55 | void avr32_backtrace(struct pt_regs * const regs, unsigned int depth) | ||
56 | { | ||
57 | /* Get first frame pointer */ | ||
58 | struct frame_head *head = (struct frame_head *)(regs->r7); | ||
59 | |||
60 | if (!user_mode(regs)) { | ||
61 | #ifdef CONFIG_FRAME_POINTER | ||
62 | /* | ||
63 | * Traverse the kernel stack from frame to frame up to | ||
64 | * "depth" steps. | ||
65 | */ | ||
66 | while (depth-- && valid_stack_ptr(task_thread_info(current), | ||
67 | (unsigned long)head)) { | ||
68 | oprofile_add_trace(head->lr); | ||
69 | if (head->fp <= head) | ||
70 | break; | ||
71 | head = head->fp; | ||
72 | } | ||
73 | #endif | ||
74 | } else { | ||
75 | /* Assume we have frame pointers in user mode process */ | ||
76 | while (depth-- && head) | ||
77 | head = dump_user_backtrace(head); | ||
78 | } | ||
79 | } | ||
80 | |||
81 | |||