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8#include <linux/uaccess.h>
9#include <linux/stop_machine.h>
10#include <linux/jump_label.h>
11#include <asm/ipl.h>
12
13#ifdef HAVE_JUMP_LABEL
14
15struct insn {
16 u16 opcode;
17 s32 offset;
18} __packed;
19
20struct insn_args {
21 struct jump_entry *entry;
22 enum jump_label_type type;
23};
24
25static void jump_label_make_nop(struct jump_entry *entry, struct insn *insn)
26{
27
28 insn->opcode = 0xc004;
29 insn->offset = 0;
30}
31
32static void jump_label_make_branch(struct jump_entry *entry, struct insn *insn)
33{
34
35 insn->opcode = 0xc0f4;
36 insn->offset = (entry->target - entry->code) >> 1;
37}
38
39static void jump_label_bug(struct jump_entry *entry, struct insn *expected,
40 struct insn *new)
41{
42 unsigned char *ipc = (unsigned char *)entry->code;
43 unsigned char *ipe = (unsigned char *)expected;
44 unsigned char *ipn = (unsigned char *)new;
45
46 pr_emerg("Jump label code mismatch at %pS [%p]\n", ipc, ipc);
47 pr_emerg("Found: %6ph\n", ipc);
48 pr_emerg("Expected: %6ph\n", ipe);
49 pr_emerg("New: %6ph\n", ipn);
50 panic("Corrupted kernel text");
51}
52
53static struct insn orignop = {
54 .opcode = 0xc004,
55 .offset = JUMP_LABEL_NOP_OFFSET >> 1,
56};
57
58static void __jump_label_transform(struct jump_entry *entry,
59 enum jump_label_type type,
60 int init)
61{
62 struct insn old, new;
63
64 if (type == JUMP_LABEL_JMP) {
65 jump_label_make_nop(entry, &old);
66 jump_label_make_branch(entry, &new);
67 } else {
68 jump_label_make_branch(entry, &old);
69 jump_label_make_nop(entry, &new);
70 }
71 if (init) {
72 if (memcmp((void *)entry->code, &orignop, sizeof(orignop)))
73 jump_label_bug(entry, &orignop, &new);
74 } else {
75 if (memcmp((void *)entry->code, &old, sizeof(old)))
76 jump_label_bug(entry, &old, &new);
77 }
78 s390_kernel_write((void *)entry->code, &new, sizeof(new));
79}
80
81static int __sm_arch_jump_label_transform(void *data)
82{
83 struct insn_args *args = data;
84
85 __jump_label_transform(args->entry, args->type, 0);
86 return 0;
87}
88
89void arch_jump_label_transform(struct jump_entry *entry,
90 enum jump_label_type type)
91{
92 struct insn_args args;
93
94 args.entry = entry;
95 args.type = type;
96
97 stop_machine_cpuslocked(__sm_arch_jump_label_transform, &args, NULL);
98}
99
100void arch_jump_label_transform_static(struct jump_entry *entry,
101 enum jump_label_type type)
102{
103 __jump_label_transform(entry, type, 1);
104}
105
106#endif
107