jump_label.h

 1/* SPDX-License-Identifier: GPL-2.0-only */
 2/*
 3 * Copyright (C) 2023 Loongson Technology Corporation Limited
 4 *
 5 * Based on arch/arm64/include/asm/jump_label.h
 6 */
 7#ifndef __ASM_JUMP_LABEL_H
 8#define __ASM_JUMP_LABEL_H
 9
10#ifndef __ASSEMBLER__
11
12#include <linux/types.h>
13#include <linux/stringify.h>
14#include <asm/asm.h>
15
16#define JUMP_LABEL_NOP_SIZE	4
17
18#ifdef CONFIG_32BIT
19#define JUMP_LABEL_TYPE		".long "
20#else
21#define JUMP_LABEL_TYPE		".quad "
22#endif
23
24/* This macro is also expanded on the Rust side. */
25#define JUMP_TABLE_ENTRY(key, label)			\
26	 ".pushsection	__jump_table, \"aw\"	\n\t"	\
27	 ".align	" __stringify(PTRLOG) "	\n\t"	\
28	 ".long		1b - ., " label " - .	\n\t"	\
29	 JUMP_LABEL_TYPE  key " - .		\n\t"	\
30	 ".popsection				\n\t"
31
32#define ARCH_STATIC_BRANCH_ASM(key, label)		\
33	"1:	nop				\n\t"	\
34	JUMP_TABLE_ENTRY(key, label)
35
36static __always_inline bool arch_static_branch(struct static_key * const key, const bool branch)
37{
38	asm goto(
39		ARCH_STATIC_BRANCH_ASM("%0", "%l[l_yes]")
40		:  :  "i"(&((char *)key)[branch]) :  : l_yes);
41
42	return false;
43
44l_yes:
45	return true;
46}
47
48static __always_inline bool arch_static_branch_jump(struct static_key * const key, const bool branch)
49{
50	asm goto(
51		"1:	b	%l[l_yes]	\n\t"
52		JUMP_TABLE_ENTRY("%0", "%l[l_yes]")
53		:  :  "i"(&((char *)key)[branch]) :  : l_yes);
54
55	return false;
56
57l_yes:
58	return true;
59}
60
61#endif  /* __ASSEMBLER__ */
62#endif	/* __ASM_JUMP_LABEL_H */