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5373db88 JG |
1 | #ifndef _ASM_S390_JUMP_LABEL_H |
2 | #define _ASM_S390_JUMP_LABEL_H | |
3 | ||
4 | #include <linux/types.h> | |
5 | ||
6 | #define JUMP_LABEL_NOP_SIZE 6 | |
d5caa4db | 7 | #define JUMP_LABEL_NOP_OFFSET 2 |
5373db88 JG |
8 | |
9 | #ifdef CONFIG_64BIT | |
10 | #define ASM_PTR ".quad" | |
11 | #define ASM_ALIGN ".balign 8" | |
12 | #else | |
13 | #define ASM_PTR ".long" | |
14 | #define ASM_ALIGN ".balign 4" | |
15 | #endif | |
16 | ||
d5caa4db HC |
17 | /* |
18 | * We use a brcl 0,2 instruction for jump labels at compile time so it | |
19 | * can be easily distinguished from a hotpatch generated instruction. | |
20 | */ | |
c5905afb | 21 | static __always_inline bool arch_static_branch(struct static_key *key) |
5373db88 | 22 | { |
d5caa4db | 23 | asm_volatile_goto("0: brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n" |
5373db88 JG |
24 | ".pushsection __jump_table, \"aw\"\n" |
25 | ASM_ALIGN "\n" | |
26 | ASM_PTR " 0b, %l[label], %0\n" | |
27 | ".popsection\n" | |
28 | : : "X" (key) : : label); | |
29 | return false; | |
30 | label: | |
31 | return true; | |
32 | } | |
33 | ||
34 | typedef unsigned long jump_label_t; | |
35 | ||
36 | struct jump_entry { | |
37 | jump_label_t code; | |
38 | jump_label_t target; | |
39 | jump_label_t key; | |
40 | }; | |
41 | ||
42 | #endif |