1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /**
3 * Copyright (C) 2005 Brian Rogan <bcr6@cornell.edu>, IBM
4 *
5 **/
6
7 #include <linux/time.h>
8 #include <linux/oprofile.h>
9 #include <linux/sched.h>
10 #include <asm/processor.h>
11 #include <linux/uaccess.h>
12 #include <linux/compat.h>
13 #include <asm/oprofile_impl.h>
14
15 #define STACK_SP(STACK) *(STACK)
16
17 #define STACK_LR64(STACK) *((unsigned long *)(STACK) + 2)
18 #define STACK_LR32(STACK) *((unsigned int *)(STACK) + 1)
19
20 #ifdef CONFIG_PPC64
21 #define STACK_LR(STACK) STACK_LR64(STACK)
22 #else
23 #define STACK_LR(STACK) STACK_LR32(STACK)
24 #endif
25
user_getsp32(unsigned int sp,int is_first)26 static unsigned int user_getsp32(unsigned int sp, int is_first)
27 {
28 unsigned int stack_frame[2];
29 void __user *p = compat_ptr(sp);
30
31 /*
32 * The most likely reason for this is that we returned -EFAULT,
33 * which means that we've done all that we can do from
34 * interrupt context.
35 */
36 if (copy_from_user_nofault(stack_frame, (void __user *)p,
37 sizeof(stack_frame)))
38 return 0;
39
40 if (!is_first)
41 oprofile_add_trace(STACK_LR32(stack_frame));
42
43 /*
44 * We do not enforce increasing stack addresses here because
45 * we may transition to a different stack, eg a signal handler.
46 */
47 return STACK_SP(stack_frame);
48 }
49
50 #ifdef CONFIG_PPC64
user_getsp64(unsigned long sp,int is_first)51 static unsigned long user_getsp64(unsigned long sp, int is_first)
52 {
53 unsigned long stack_frame[3];
54
55 if (copy_from_user_nofault(stack_frame, (void __user *)sp,
56 sizeof(stack_frame)))
57 return 0;
58
59 if (!is_first)
60 oprofile_add_trace(STACK_LR64(stack_frame));
61
62 return STACK_SP(stack_frame);
63 }
64 #endif
65
kernel_getsp(unsigned long sp,int is_first)66 static unsigned long kernel_getsp(unsigned long sp, int is_first)
67 {
68 unsigned long *stack_frame = (unsigned long *)sp;
69
70 if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
71 return 0;
72
73 if (!is_first)
74 oprofile_add_trace(STACK_LR(stack_frame));
75
76 /*
77 * We do not enforce increasing stack addresses here because
78 * we might be transitioning from an interrupt stack to a kernel
79 * stack. validate_sp() is designed to understand this, so just
80 * use it.
81 */
82 return STACK_SP(stack_frame);
83 }
84
op_powerpc_backtrace(struct pt_regs * const regs,unsigned int depth)85 void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
86 {
87 unsigned long sp = regs->gpr[1];
88 int first_frame = 1;
89
90 /* We ditch the top stackframe so need to loop through an extra time */
91 depth += 1;
92
93 if (!user_mode(regs)) {
94 while (depth--) {
95 sp = kernel_getsp(sp, first_frame);
96 if (!sp)
97 break;
98 first_frame = 0;
99 }
100 } else {
101 #ifdef CONFIG_PPC64
102 if (!is_32bit_task()) {
103 while (depth--) {
104 sp = user_getsp64(sp, first_frame);
105 if (!sp)
106 break;
107 first_frame = 0;
108 }
109 return;
110 }
111 #endif
112
113 while (depth--) {
114 sp = user_getsp32(sp, first_frame);
115 if (!sp)
116 break;
117 first_frame = 0;
118 }
119 }
120 }
121
