jump_label.h

 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