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
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
|
/*
* Copyright (C) 2012 Rabin Vincent <rabin at rab.in>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/errno.h>
#include <linux/highmem.h>
#include <linux/sched.h>
#include <linux/uprobes.h>
#include <linux/notifier.h>
#include <asm/opcodes.h>
#include <asm/traps.h>
#include "probes.h"
#include "probes-arm.h"
#include "uprobes.h"
#define UPROBE_TRAP_NR UINT_MAX
bool is_swbp_insn(uprobe_opcode_t *insn)
{
return (__mem_to_opcode_arm(*insn) & 0x0fffffff) ==
(UPROBE_SWBP_ARM_INSN & 0x0fffffff);
}
int set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm,
unsigned long vaddr)
{
return uprobe_write_opcode(mm, vaddr,
__opcode_to_mem_arm(auprobe->bpinsn));
}
bool arch_uprobe_ignore(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
if (!auprobe->asi.insn_check_cc(regs->ARM_cpsr)) {
regs->ARM_pc += 4;
return true;
}
return false;
}
bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
probes_opcode_t opcode;
if (!auprobe->simulate)
return false;
opcode = __mem_to_opcode_arm(*(unsigned int *) auprobe->insn);
auprobe->asi.insn_singlestep(opcode, &auprobe->asi, regs);
return true;
}
unsigned long
arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
struct pt_regs *regs)
{
unsigned long orig_ret_vaddr;
orig_ret_vaddr = regs->ARM_lr;
/* Replace the return addr with trampoline addr */
regs->ARM_lr = trampoline_vaddr;
return orig_ret_vaddr;
}
int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
unsigned long addr)
{
unsigned int insn;
unsigned int bpinsn;
enum probes_insn ret;
/* Thumb not yet support */
if (addr & 0x3)
return -EINVAL;
insn = __mem_to_opcode_arm(*(unsigned int *)auprobe->insn);
auprobe->ixol[0] = __opcode_to_mem_arm(insn);
auprobe->ixol[1] = __opcode_to_mem_arm(UPROBE_SS_ARM_INSN);
ret = arm_probes_decode_insn(insn, &auprobe->asi, false,
uprobes_probes_actions);
switch (ret) {
case INSN_REJECTED:
return -EINVAL;
case INSN_GOOD_NO_SLOT:
auprobe->simulate = true;
break;
case INSN_GOOD:
default:
break;
}
bpinsn = UPROBE_SWBP_ARM_INSN & 0x0fffffff;
if (insn >= 0xe0000000)
bpinsn |= 0xe0000000; /* Unconditional instruction */
else
bpinsn |= insn & 0xf0000000; /* Copy condition from insn */
auprobe->bpinsn = bpinsn;
return 0;
}
void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
void *src, unsigned long len)
{
void *xol_page_kaddr = kmap_atomic(page);
void *dst = xol_page_kaddr + (vaddr & ~PAGE_MASK);
preempt_disable();
/* Initialize the slot */
memcpy(dst, src, len);
/* flush caches (dcache/icache) */
flush_uprobe_xol_access(page, vaddr, dst, len);
preempt_enable();
kunmap_atomic(xol_page_kaddr);
}
int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
struct uprobe_task *utask = current->utask;
if (auprobe->prehandler)
auprobe->prehandler(auprobe, &utask->autask, regs);
utask->autask.saved_trap_no = current->thread.trap_no;
current->thread.trap_no = UPROBE_TRAP_NR;
regs->ARM_pc = utask->xol_vaddr;
return 0;
}
int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
struct uprobe_task *utask = current->utask;
WARN_ON_ONCE(current->thread.trap_no != UPROBE_TRAP_NR);
current->thread.trap_no = utask->autask.saved_trap_no;
regs->ARM_pc = utask->vaddr + 4;
if (auprobe->posthandler)
auprobe->posthandler(auprobe, &utask->autask, regs);
return 0;
}
bool arch_uprobe_xol_was_trapped(struct task_struct *t)
{
if (t->thread.trap_no != UPROBE_TRAP_NR)
return true;
return false;
}
void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
struct uprobe_task *utask = current->utask;
current->thread.trap_no = utask->autask.saved_trap_no;
instruction_pointer_set(regs, utask->vaddr);
}
int arch_uprobe_exception_notify(struct notifier_block *self,
unsigned long val, void *data)
{
return NOTIFY_DONE;
}
static int uprobe_trap_handler(struct pt_regs *regs, unsigned int instr)
{
unsigned long flags;
local_irq_save(flags);
instr &= 0x0fffffff;
if (instr == (UPROBE_SWBP_ARM_INSN & 0x0fffffff))
uprobe_pre_sstep_notifier(regs);
else if (instr == (UPROBE_SS_ARM_INSN & 0x0fffffff))
uprobe_post_sstep_notifier(regs);
local_irq_restore(flags);
return 0;
}
unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
{
return instruction_pointer(regs);
}
static struct undef_hook uprobes_arm_break_hook = {
.instr_mask = 0x0fffffff,
.instr_val = (UPROBE_SWBP_ARM_INSN & 0x0fffffff),
.cpsr_mask = MODE_MASK,
.cpsr_val = USR_MODE,
.fn = uprobe_trap_handler,
};
static struct undef_hook uprobes_arm_ss_hook = {
.instr_mask = 0x0fffffff,
.instr_val = (UPROBE_SS_ARM_INSN & 0x0fffffff),
.cpsr_mask = MODE_MASK,
.cpsr_val = USR_MODE,
.fn = uprobe_trap_handler,
};
static int arch_uprobes_init(void)
{
register_undef_hook(&uprobes_arm_break_hook);
register_undef_hook(&uprobes_arm_ss_hook);
return 0;
}
device_initcall(arch_uprobes_init);
|
