jump_label.h

 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 __ASSEMBLER__
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  /* __ASSEMBLER__ */
62#endif	/* __ASM_JUMP_LABEL_H */