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7#include <linux/jump_label.h>
8#include <linux/memory.h>
9#include <linux/uaccess.h>
10#include <linux/module.h>
11#include <linux/list.h>
12#include <linux/jhash.h>
13#include <linux/cpu.h>
14#include <asm/kprobes.h>
15#include <asm/alternative.h>
16
17#ifdef HAVE_JUMP_LABEL
18
19union jump_code_union {
20 char code[JUMP_LABEL_NOP_SIZE];
21 struct {
22 char jump;
23 int offset;
24 } __attribute__((packed));
25};
26
27static void bug_at(unsigned char *ip, int line)
28{
29
30
31
32
33
34 pr_warning("Unexpected op at %pS [%p] (%02x %02x %02x %02x %02x) %s:%d\n",
35 ip, ip, ip[0], ip[1], ip[2], ip[3], ip[4], __FILE__, line);
36 BUG();
37}
38
39static void __jump_label_transform(struct jump_entry *entry,
40 enum jump_label_type type,
41 void *(*poker)(void *, const void *, size_t),
42 int init)
43{
44 union jump_code_union code;
45 const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP };
46 const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5];
47
48 if (type == JUMP_LABEL_JMP) {
49 if (init) {
50
51
52
53
54 if (unlikely(memcmp((void *)entry->code, default_nop, 5)
55 != 0))
56 bug_at((void *)entry->code, __LINE__);
57 } else {
58
59
60
61
62 if (unlikely(memcmp((void *)entry->code, ideal_nop, 5)
63 != 0))
64 bug_at((void *)entry->code, __LINE__);
65 }
66
67 code.jump = 0xe9;
68 code.offset = entry->target -
69 (entry->code + JUMP_LABEL_NOP_SIZE);
70 } else {
71
72
73
74
75
76
77 if (init) {
78 if (unlikely(memcmp((void *)entry->code, default_nop, 5) != 0))
79 bug_at((void *)entry->code, __LINE__);
80 } else {
81 code.jump = 0xe9;
82 code.offset = entry->target -
83 (entry->code + JUMP_LABEL_NOP_SIZE);
84 if (unlikely(memcmp((void *)entry->code, &code, 5) != 0))
85 bug_at((void *)entry->code, __LINE__);
86 }
87 memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE);
88 }
89
90
91
92
93
94
95
96
97
98 if (poker)
99 (*poker)((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
100 else
101 text_poke_bp((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE,
102 (void *)entry->code + JUMP_LABEL_NOP_SIZE);
103}
104
105void arch_jump_label_transform(struct jump_entry *entry,
106 enum jump_label_type type)
107{
108 get_online_cpus();
109 mutex_lock(&text_mutex);
110 __jump_label_transform(entry, type, NULL, 0);
111 mutex_unlock(&text_mutex);
112 put_online_cpus();
113}
114
115static enum {
116 JL_STATE_START,
117 JL_STATE_NO_UPDATE,
118 JL_STATE_UPDATE,
119} jlstate __initdata_or_module = JL_STATE_START;
120
121__init_or_module void arch_jump_label_transform_static(struct jump_entry *entry,
122 enum jump_label_type type)
123{
124
125
126
127
128
129
130
131 if (jlstate == JL_STATE_START) {
132 const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP };
133 const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5];
134
135 if (memcmp(ideal_nop, default_nop, 5) != 0)
136 jlstate = JL_STATE_UPDATE;
137 else
138 jlstate = JL_STATE_NO_UPDATE;
139 }
140 if (jlstate == JL_STATE_UPDATE)
141 __jump_label_transform(entry, type, text_poke_early, 1);
142}
143
144#endif
145