jump label: x86 support
[deliverable/linux.git] / arch / x86 / kernel / jump_label.c
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d9f5ab7b
JB
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
19union jump_code_union {
20 char code[JUMP_LABEL_NOP_SIZE];
21 struct {
22 char jump;
23 int offset;
24 } __attribute__((packed));
25};
26
27void 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
45void 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
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