tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2013 Huawei Ltd.
4 * Author: Jiang Liu <liuj97@gmail.com>
5 *
6 * Based on arch/arm/include/asm/jump_label.h
7 */
8#ifndef __ASM_JUMP_LABEL_H
9#define __ASM_JUMP_LABEL_H
10
11#ifndef __ASSEMBLY__
12
13#include <linux/types.h>
14#include <asm/insn.h>
15
16#define HAVE_JUMP_LABEL_BATCH
17#define JUMP_LABEL_NOP_SIZE AARCH64_INSN_SIZE
18
19#define JUMP_TABLE_ENTRY(key, label) \
20 ".pushsection __jump_table, \"aw\"\n\t" \
21 ".align 3\n\t" \
22 ".long 1b - ., " label " - .\n\t" \
23 ".quad " key " - .\n\t" \
24 ".popsection\n\t"
25
26/* This macro is also expanded on the Rust side. */
27#define ARCH_STATIC_BRANCH_ASM(key, label) \
28 "1: nop\n\t" \
29 JUMP_TABLE_ENTRY(key, label)
30
31static __always_inline bool arch_static_branch(struct static_key * const key,
32 const bool branch)
33{
34 char *k = &((char *)key)[branch];
35
36 asm goto(
37 ARCH_STATIC_BRANCH_ASM("%c0", "%l[l_yes]")
38 : : "i"(k) : : l_yes
39 );
40
41 return false;
42l_yes:
43 return true;
44}
45
46static __always_inline bool arch_static_branch_jump(struct static_key * const key,
47 const bool branch)
48{
49 char *k = &((char *)key)[branch];
50
51 asm goto(
52 "1: b %l[l_yes] \n\t"
53 JUMP_TABLE_ENTRY("%c0", "%l[l_yes]")
54 : : "i"(k) : : l_yes
55 );
56 return false;
57l_yes:
58 return true;
59}
60
61#endif /* __ASSEMBLY__ */
62#endif /* __ASM_JUMP_LABEL_H */