1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_JUMP_LABEL_H
3#define _ASM_X86_JUMP_LABEL_H
4
5#define HAVE_JUMP_LABEL_BATCH
6
7#include <asm/asm.h>
8#include <asm/nops.h>
9
10#ifndef __ASSEMBLER__
11
12#include <linux/stringify.h>
13#include <linux/types.h>
14
15#define JUMP_TABLE_ENTRY(key, label) \
16 ".pushsection __jump_table, \"aw\" \n\t" \
17 _ASM_ALIGN "\n\t" \
18 ANNOTATE_DATA_SPECIAL "\n" \
19 ".long 1b - . \n\t" \
20 ".long " label " - . \n\t" \
21 _ASM_PTR " " key " - . \n\t" \
22 ".popsection \n\t"
23
24/* This macro is also expanded on the Rust side. */
25#ifdef CONFIG_HAVE_JUMP_LABEL_HACK
26#define ARCH_STATIC_BRANCH_ASM(key, label) \
27 "1: jmp " label " # objtool NOPs this \n\t" \
28 JUMP_TABLE_ENTRY(key " + 2", label)
29#else /* !CONFIG_HAVE_JUMP_LABEL_HACK */
30#define ARCH_STATIC_BRANCH_ASM(key, label) \
31 "1: .byte " __stringify(BYTES_NOP5) "\n\t" \
32 JUMP_TABLE_ENTRY(key, label)
33#endif /* CONFIG_HAVE_JUMP_LABEL_HACK */
34
35static __always_inline bool arch_static_branch(struct static_key * const key, const bool branch)
36{
37 asm goto(ARCH_STATIC_BRANCH_ASM("%c0 + %c1", "%l[l_yes]")
38 : : "i" (key), "i" (branch) : : l_yes);
39
40 return false;
41l_yes:
42 return true;
43}
44
45static __always_inline bool arch_static_branch_jump(struct static_key * const key, const bool branch)
46{
47 asm goto("1:"
48 "jmp %l[l_yes]\n\t"
49 JUMP_TABLE_ENTRY("%c0 + %c1", "%l[l_yes]")
50 : : "i" (key), "i" (branch) : : l_yes);
51
52 return false;
53l_yes:
54 return true;
55}
56
57extern int arch_jump_entry_size(struct jump_entry *entry);
58
59#endif /* __ASSEMBLER__ */
60
61#endif
62

source code of linux/arch/x86/include/asm/jump_label.h