jump_label.h

 1/* SPDX-License-Identifier: GPL-2.0-only */
 2/*
 3 * Copyright (C) 2020 Emil Renner Berthing
 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 <asm/asm.h>
14
15#define HAVE_JUMP_LABEL_BATCH
16
17#define JUMP_LABEL_NOP_SIZE 4
18
19#define JUMP_TABLE_ENTRY(key, label)			\
20	".pushsection	__jump_table, \"aw\"	\n\t"	\
21	".align		" RISCV_LGPTR "		\n\t"	\
22	".long		1b - ., " label " - .	\n\t"	\
23	"" RISCV_PTR "	" 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	"	.align		2		\n\t"	\
29	"	.option push			\n\t"	\
30	"	.option norelax			\n\t"	\
31	"	.option norvc			\n\t"	\
32	"1:	nop				\n\t"	\
33	"	.option pop			\n\t"	\
34	JUMP_TABLE_ENTRY(key, label)
35
36static __always_inline bool arch_static_branch(struct static_key * const key,
37					       const bool branch)
38{
39	asm goto(
40		ARCH_STATIC_BRANCH_ASM("%0", "%l[label]")
41		:  :  "i"(&((char *)key)[branch]) :  : label);
42
43	return false;
44label:
45	return true;
46}
47
48#define ARCH_STATIC_BRANCH_JUMP_ASM(key, label)		\
49	"	.align		2		\n\t"	\
50	"	.option push			\n\t"	\
51	"	.option norelax			\n\t"	\
52	"	.option norvc			\n\t"	\
53	"1:	j	" label "		\n\t" \
54	"	.option pop			\n\t"	\
55	JUMP_TABLE_ENTRY(key, label)
56
57static __always_inline bool arch_static_branch_jump(struct static_key * const key,
58						    const bool branch)
59{
60	asm goto(
61		ARCH_STATIC_BRANCH_JUMP_ASM("%0", "%l[label]")
62		:  :  "i"(&((char *)key)[branch]) :  : label);
63
64	return false;
65label:
66	return true;
67}
68
69#endif  /* __ASSEMBLER__ */
70#endif	/* __ASM_JUMP_LABEL_H */