1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2022 Loongson Technology Corporation Limited
*/
#include <linux/kallsyms.h>
#include <asm/inst.h>
#include <asm/ptrace.h>
#include <asm/unwind.h>
unsigned long unwind_get_return_address(struct unwind_state *state)
{
if (unwind_done(state))
return 0;
else if (state->type)
return state->pc;
else if (state->first)
return state->pc;
return *(unsigned long *)(state->sp);
}
EXPORT_SYMBOL_GPL(unwind_get_return_address);
static bool unwind_by_guess(struct unwind_state *state)
{
struct stack_info *info = &state->stack_info;
unsigned long addr;
for (state->sp += sizeof(unsigned long);
state->sp < info->end;
state->sp += sizeof(unsigned long)) {
addr = *(unsigned long *)(state->sp);
if (__kernel_text_address(addr))
return true;
}
return false;
}
static bool unwind_by_prologue(struct unwind_state *state)
{
struct stack_info *info = &state->stack_info;
union loongarch_instruction *ip, *ip_end;
long frame_ra = -1;
unsigned long frame_size = 0;
unsigned long size, offset, pc = state->pc;
if (state->sp >= info->end || state->sp < info->begin)
return false;
if (!kallsyms_lookup_size_offset(pc, &size, &offset))
return false;
ip = (union loongarch_instruction *)(pc - offset);
ip_end = (union loongarch_instruction *)pc;
while (ip < ip_end) {
if (is_stack_alloc_ins(ip)) {
frame_size = (1 << 12) - ip->reg2i12_format.immediate;
ip++;
break;
}
ip++;
}
if (!frame_size) {
if (state->first)
goto first;
return false;
}
while (ip < ip_end) {
if (is_ra_save_ins(ip)) {
frame_ra = ip->reg2i12_format.immediate;
break;
}
if (is_branch_ins(ip))
break;
ip++;
}
if (frame_ra < 0) {
if (state->first) {
state->sp = state->sp + frame_size;
goto first;
}
return false;
}
if (state->first)
state->first = false;
state->pc = *(unsigned long *)(state->sp + frame_ra);
state->sp = state->sp + frame_size;
return !!__kernel_text_address(state->pc);
first:
state->first = false;
if (state->pc == state->ra)
return false;
state->pc = state->ra;
return !!__kernel_text_address(state->ra);
}
void unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs)
{
memset(state, 0, sizeof(*state));
if (regs && __kernel_text_address(regs->csr_era)) {
state->pc = regs->csr_era;
state->sp = regs->regs[3];
state->ra = regs->regs[1];
state->type = UNWINDER_PROLOGUE;
}
state->task = task;
state->first = true;
get_stack_info(state->sp, state->task, &state->stack_info);
if (!unwind_done(state) && !__kernel_text_address(state->pc))
unwind_next_frame(state);
}
EXPORT_SYMBOL_GPL(unwind_start);
bool unwind_next_frame(struct unwind_state *state)
{
struct stack_info *info = &state->stack_info;
struct pt_regs *regs;
unsigned long pc;
if (unwind_done(state))
return false;
do {
switch (state->type) {
case UNWINDER_GUESS:
state->first = false;
if (unwind_by_guess(state))
return true;
break;
case UNWINDER_PROLOGUE:
if (unwind_by_prologue(state))
return true;
if (info->type == STACK_TYPE_IRQ &&
info->end == state->sp) {
regs = (struct pt_regs *)info->next_sp;
pc = regs->csr_era;
if (user_mode(regs) || !__kernel_text_address(pc))
return false;
state->pc = pc;
state->sp = regs->regs[3];
state->ra = regs->regs[1];
state->first = true;
get_stack_info(state->sp, state->task, info);
return true;
}
}
state->sp = info->next_sp;
} while (!get_stack_info(state->sp, state->task, info));
return false;
}
EXPORT_SYMBOL_GPL(unwind_next_frame);
|
