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
|
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/stop_machine.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/fixmap.h>
#include <asm/insn.h>
#include <asm/kprobes.h>
#include <asm/patching.h>
#include <asm/sections.h>
static DEFINE_RAW_SPINLOCK(patch_lock);
static bool is_exit_text(unsigned long addr)
{
/* discarded with init text/data */
return system_state < SYSTEM_RUNNING &&
addr >= (unsigned long)__exittext_begin &&
addr < (unsigned long)__exittext_end;
}
static bool is_image_text(unsigned long addr)
{
return core_kernel_text(addr) || is_exit_text(addr);
}
static void __kprobes *patch_map(void *addr, int fixmap)
{
unsigned long uintaddr = (uintptr_t) addr;
bool image = is_image_text(uintaddr);
struct page *page;
if (image)
page = phys_to_page(__pa_symbol(addr));
else if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
page = vmalloc_to_page(addr);
else
return addr;
BUG_ON(!page);
return (void *)set_fixmap_offset(fixmap, page_to_phys(page) +
(uintaddr & ~PAGE_MASK));
}
static void __kprobes patch_unmap(int fixmap)
{
clear_fixmap(fixmap);
}
/*
* In ARMv8-A, A64 instructions have a fixed length of 32 bits and are always
* little-endian.
*/
int __kprobes aarch64_insn_read(void *addr, u32 *insnp)
{
int ret;
__le32 val;
ret = copy_from_kernel_nofault(&val, addr, AARCH64_INSN_SIZE);
if (!ret)
*insnp = le32_to_cpu(val);
return ret;
}
static int __kprobes __aarch64_insn_write(void *addr, __le32 insn)
{
void *waddr = addr;
unsigned long flags = 0;
int ret;
raw_spin_lock_irqsave(&patch_lock, flags);
waddr = patch_map(addr, FIX_TEXT_POKE0);
ret = copy_to_kernel_nofault(waddr, &insn, AARCH64_INSN_SIZE);
patch_unmap(FIX_TEXT_POKE0);
raw_spin_unlock_irqrestore(&patch_lock, flags);
return ret;
}
int __kprobes aarch64_insn_write(void *addr, u32 insn)
{
return __aarch64_insn_write(addr, cpu_to_le32(insn));
}
noinstr int aarch64_insn_write_literal_u64(void *addr, u64 val)
{
u64 *waddr;
unsigned long flags;
int ret;
raw_spin_lock_irqsave(&patch_lock, flags);
waddr = patch_map(addr, FIX_TEXT_POKE0);
ret = copy_to_kernel_nofault(waddr, &val, sizeof(val));
patch_unmap(FIX_TEXT_POKE0);
raw_spin_unlock_irqrestore(&patch_lock, flags);
return ret;
}
int __kprobes aarch64_insn_patch_text_nosync(void *addr, u32 insn)
{
u32 *tp = addr;
int ret;
/* A64 instructions must be word aligned */
if ((uintptr_t)tp & 0x3)
return -EINVAL;
ret = aarch64_insn_write(tp, insn);
if (ret == 0)
caches_clean_inval_pou((uintptr_t)tp,
(uintptr_t)tp + AARCH64_INSN_SIZE);
return ret;
}
struct aarch64_insn_patch {
void **text_addrs;
u32 *new_insns;
int insn_cnt;
atomic_t cpu_count;
};
static int __kprobes aarch64_insn_patch_text_cb(void *arg)
{
int i, ret = 0;
struct aarch64_insn_patch *pp = arg;
/* The last CPU becomes master */
if (atomic_inc_return(&pp->cpu_count) == num_online_cpus()) {
for (i = 0; ret == 0 && i < pp->insn_cnt; i++)
ret = aarch64_insn_patch_text_nosync(pp->text_addrs[i],
pp->new_insns[i]);
/* Notify other processors with an additional increment. */
atomic_inc(&pp->cpu_count);
} else {
while (atomic_read(&pp->cpu_count) <= num_online_cpus())
cpu_relax();
isb();
}
return ret;
}
int __kprobes aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt)
{
struct aarch64_insn_patch patch = {
.text_addrs = addrs,
.new_insns = insns,
.insn_cnt = cnt,
.cpu_count = ATOMIC_INIT(0),
};
if (cnt <= 0)
return -EINVAL;
return stop_machine_cpuslocked(aarch64_insn_patch_text_cb, &patch,
cpu_online_mask);
}
|
