tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 ".long 1b - . \n\t" \
19 ".long " label " - . \n\t" \
20 _ASM_PTR " " key " - . \n\t" \
21 ".popsection \n\t"
22
23/* This macro is also expanded on the Rust side. */
24#ifdef CONFIG_HAVE_JUMP_LABEL_HACK
25#define ARCH_STATIC_BRANCH_ASM(key, label) \
26 "1: jmp " label " # objtool NOPs this \n\t" \
27 JUMP_TABLE_ENTRY(key " + 2", label)
28#else /* !CONFIG_HAVE_JUMP_LABEL_HACK */
29#define ARCH_STATIC_BRANCH_ASM(key, label) \
30 "1: .byte " __stringify(BYTES_NOP5) "\n\t" \
31 JUMP_TABLE_ENTRY(key, label)
32#endif /* CONFIG_HAVE_JUMP_LABEL_HACK */
33
34static __always_inline bool arch_static_branch(struct static_key * const key, const bool branch)
35{
36 asm goto(ARCH_STATIC_BRANCH_ASM("%c0 + %c1", "%l[l_yes]")
37 : : "i" (key), "i" (branch) : : l_yes);
38
39 return false;
40l_yes:
41 return true;
42}
43
44static __always_inline bool arch_static_branch_jump(struct static_key * const key, const bool branch)
45{
46 asm goto("1:"
47 "jmp %l[l_yes]\n\t"
48 JUMP_TABLE_ENTRY("%c0 + %c1", "%l[l_yes]")
49 : : "i" (key), "i" (branch) : : l_yes);
50
51 return false;
52l_yes:
53 return true;
54}
55
56extern int arch_jump_entry_size(struct jump_entry *entry);
57
58#endif /* __ASSEMBLER__ */
59
60#endif