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 <linux/uaccess.h>
14 #include <asm/compat.h>
15 #include <asm/oprofile_impl.h>
16
17 #define STACK_SP(STACK) *(STACK)
18
19 #define STACK_LR64(STACK) *((unsigned long *)(STACK) + 2)
20 #define STACK_LR32(STACK) *((unsigned int *)(STACK) + 1)
21
22 #ifdef CONFIG_PPC64
23 #define STACK_LR(STACK) STACK_LR64(STACK)
24 #else
25 #define STACK_LR(STACK) STACK_LR32(STACK)
26 #endif
27
user_getsp32(unsigned int sp,int is_first)28 static unsigned int user_getsp32(unsigned int sp, int is_first)
29 {
30 unsigned int stack_frame[2];
31 void __user *p = compat_ptr(sp);
32
33 if (!access_ok(VERIFY_READ, p, sizeof(stack_frame)))
34 return 0;
35
36 /*
37 * The most likely reason for this is that we returned -EFAULT,
38 * which means that we've done all that we can do from
39 * interrupt context.
40 */
41 if (__copy_from_user_inatomic(stack_frame, p, sizeof(stack_frame)))
42 return 0;
43
44 if (!is_first)
45 oprofile_add_trace(STACK_LR32(stack_frame));
46
47 /*
48 * We do not enforce increasing stack addresses here because
49 * we may transition to a different stack, eg a signal handler.
50 */
51 return STACK_SP(stack_frame);
52 }
53
54 #ifdef CONFIG_PPC64
user_getsp64(unsigned long sp,int is_first)55 static unsigned long user_getsp64(unsigned long sp, int is_first)
56 {
57 unsigned long stack_frame[3];
58
59 if (!access_ok(VERIFY_READ, (void __user *)sp, sizeof(stack_frame)))
60 return 0;
61
62 if (__copy_from_user_inatomic(stack_frame, (void __user *)sp,
63 sizeof(stack_frame)))
64 return 0;
65
66 if (!is_first)
67 oprofile_add_trace(STACK_LR64(stack_frame));
68
69 return STACK_SP(stack_frame);
70 }
71 #endif
72
kernel_getsp(unsigned long sp,int is_first)73 static unsigned long kernel_getsp(unsigned long sp, int is_first)
74 {
75 unsigned long *stack_frame = (unsigned long *)sp;
76
77 if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
78 return 0;
79
80 if (!is_first)
81 oprofile_add_trace(STACK_LR(stack_frame));
82
83 /*
84 * We do not enforce increasing stack addresses here because
85 * we might be transitioning from an interrupt stack to a kernel
86 * stack. validate_sp() is designed to understand this, so just
87 * use it.
88 */
89 return STACK_SP(stack_frame);
90 }
91
op_powerpc_backtrace(struct pt_regs * const regs,unsigned int depth)92 void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
93 {
94 unsigned long sp = regs->gpr[1];
95 int first_frame = 1;
96
97 /* We ditch the top stackframe so need to loop through an extra time */
98 depth += 1;
99
100 if (!user_mode(regs)) {
101 while (depth--) {
102 sp = kernel_getsp(sp, first_frame);
103 if (!sp)
104 break;
105 first_frame = 0;
106 }
107 } else {
108 pagefault_disable();
109 #ifdef CONFIG_PPC64
110 if (!is_32bit_task()) {
111 while (depth--) {
112 sp = user_getsp64(sp, first_frame);
113 if (!sp)
114 break;
115 first_frame = 0;
116 }
117 pagefault_enable();
118 return;
119 }
120 #endif
121
122 while (depth--) {
123 sp = user_getsp32(sp, first_frame);
124 if (!sp)
125 break;
126 first_frame = 0;
127 }
128 pagefault_enable();
129 }
130 }
131