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 <asm/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 if (!access_ok(p, sizeof(stack_frame)))
32 return 0;
33
34 /*
35 * The most likely reason for this is that we returned -EFAULT,
36 * which means that we've done all that we can do from
37 * interrupt context.
38 */
39 if (__copy_from_user_inatomic(stack_frame, p, sizeof(stack_frame)))
40 return 0;
41
42 if (!is_first)
43 oprofile_add_trace(STACK_LR32(stack_frame));
44
45 /*
46 * We do not enforce increasing stack addresses here because
47 * we may transition to a different stack, eg a signal handler.
48 */
49 return STACK_SP(stack_frame);
50 }
51
52 #ifdef CONFIG_PPC64
user_getsp64(unsigned long sp,int is_first)53 static unsigned long user_getsp64(unsigned long sp, int is_first)
54 {
55 unsigned long stack_frame[3];
56
57 if (!access_ok((void __user *)sp, sizeof(stack_frame)))
58 return 0;
59
60 if (__copy_from_user_inatomic(stack_frame, (void __user *)sp,
61 sizeof(stack_frame)))
62 return 0;
63
64 if (!is_first)
65 oprofile_add_trace(STACK_LR64(stack_frame));
66
67 return STACK_SP(stack_frame);
68 }
69 #endif
70
kernel_getsp(unsigned long sp,int is_first)71 static unsigned long kernel_getsp(unsigned long sp, int is_first)
72 {
73 unsigned long *stack_frame = (unsigned long *)sp;
74
75 if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
76 return 0;
77
78 if (!is_first)
79 oprofile_add_trace(STACK_LR(stack_frame));
80
81 /*
82 * We do not enforce increasing stack addresses here because
83 * we might be transitioning from an interrupt stack to a kernel
84 * stack. validate_sp() is designed to understand this, so just
85 * use it.
86 */
87 return STACK_SP(stack_frame);
88 }
89
op_powerpc_backtrace(struct pt_regs * const regs,unsigned int depth)90 void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
91 {
92 unsigned long sp = regs->gpr[1];
93 int first_frame = 1;
94
95 /* We ditch the top stackframe so need to loop through an extra time */
96 depth += 1;
97
98 if (!user_mode(regs)) {
99 while (depth--) {
100 sp = kernel_getsp(sp, first_frame);
101 if (!sp)
102 break;
103 first_frame = 0;
104 }
105 } else {
106 pagefault_disable();
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 pagefault_enable();
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 pagefault_enable();
127 }
128 }
129
