1 /**
2 * Copyright (C) 2005 Brian Rogan <bcr6@cornell.edu>, IBM
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 **/
9
10 #include <linux/oprofile.h>
11 #include <linux/sched.h>
12 #include <asm/processor.h>
13 #include <asm/uaccess.h>
14 #include <asm/compat.h>
15
16 #define STACK_SP(STACK) *(STACK)
17
18 #define STACK_LR64(STACK) *((unsigned long *)(STACK) + 2)
19 #define STACK_LR32(STACK) *((unsigned int *)(STACK) + 1)
20
21 #ifdef CONFIG_PPC64
22 #define STACK_LR(STACK) STACK_LR64(STACK)
23 #else
24 #define STACK_LR(STACK) STACK_LR32(STACK)
25 #endif
26
user_getsp32(unsigned int sp,int is_first)27 static unsigned int user_getsp32(unsigned int sp, int is_first)
28 {
29 unsigned int stack_frame[2];
30 void __user *p = compat_ptr(sp);
31
32 if (!access_ok(VERIFY_READ, p, sizeof(stack_frame)))
33 return 0;
34
35 /*
36 * The most likely reason for this is that we returned -EFAULT,
37 * which means that we've done all that we can do from
38 * interrupt context.
39 */
40 if (__copy_from_user_inatomic(stack_frame, p, sizeof(stack_frame)))
41 return 0;
42
43 if (!is_first)
44 oprofile_add_trace(STACK_LR32(stack_frame));
45
46 /*
47 * We do not enforce increasing stack addresses here because
48 * we may transition to a different stack, eg a signal handler.
49 */
50 return STACK_SP(stack_frame);
51 }
52
53 #ifdef CONFIG_PPC64
user_getsp64(unsigned long sp,int is_first)54 static unsigned long user_getsp64(unsigned long sp, int is_first)
55 {
56 unsigned long stack_frame[3];
57
58 if (!access_ok(VERIFY_READ, (void __user *)sp, sizeof(stack_frame)))
59 return 0;
60
61 if (__copy_from_user_inatomic(stack_frame, (void __user *)sp,
62 sizeof(stack_frame)))
63 return 0;
64
65 if (!is_first)
66 oprofile_add_trace(STACK_LR64(stack_frame));
67
68 return STACK_SP(stack_frame);
69 }
70 #endif
71
kernel_getsp(unsigned long sp,int is_first)72 static unsigned long kernel_getsp(unsigned long sp, int is_first)
73 {
74 unsigned long *stack_frame = (unsigned long *)sp;
75
76 if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
77 return 0;
78
79 if (!is_first)
80 oprofile_add_trace(STACK_LR(stack_frame));
81
82 /*
83 * We do not enforce increasing stack addresses here because
84 * we might be transitioning from an interrupt stack to a kernel
85 * stack. validate_sp() is designed to understand this, so just
86 * use it.
87 */
88 return STACK_SP(stack_frame);
89 }
90
op_powerpc_backtrace(struct pt_regs * const regs,unsigned int depth)91 void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
92 {
93 unsigned long sp = regs->gpr[1];
94 int first_frame = 1;
95
96 /* We ditch the top stackframe so need to loop through an extra time */
97 depth += 1;
98
99 if (!user_mode(regs)) {
100 while (depth--) {
101 sp = kernel_getsp(sp, first_frame);
102 if (!sp)
103 break;
104 first_frame = 0;
105 }
106 } else {
107 #ifdef CONFIG_PPC64
108 if (!is_32bit_task()) {
109 while (depth--) {
110 sp = user_getsp64(sp, first_frame);
111 if (!sp)
112 break;
113 first_frame = 0;
114 }
115
116 return;
117 }
118 #endif
119
120 while (depth--) {
121 sp = user_getsp32(sp, first_frame);
122 if (!sp)
123 break;
124 first_frame = 0;
125 }
126 }
127 }
128