Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[linux-2.6.git] / arch / x86 / kernel / jump_label.c
1 /*
2  * jump label x86 support
3  *
4  * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
5  *
6  */
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
19 union jump_code_union {
20         char code[JUMP_LABEL_NOP_SIZE];
21         struct {
22                 char jump;
23                 int offset;
24         } __attribute__((packed));
25 };
26
27 void arch_jump_label_transform(struct jump_entry *entry,
28                                enum jump_label_type type)
29 {
30         union jump_code_union code;
31
32         if (type == JUMP_LABEL_ENABLE) {
33                 code.jump = 0xe9;
34                 code.offset = entry->target -
35                                 (entry->code + JUMP_LABEL_NOP_SIZE);
36         } else
37                 memcpy(&code, ideal_nop5, JUMP_LABEL_NOP_SIZE);
38         get_online_cpus();
39         mutex_lock(&text_mutex);
40         text_poke_smp((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
41         mutex_unlock(&text_mutex);
42         put_online_cpus();
43 }
44
45 void arch_jump_label_text_poke_early(jump_label_t addr)
46 {
47         text_poke_early((void *)addr, ideal_nop5, JUMP_LABEL_NOP_SIZE);
48 }
49
50 #endif