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5373db88 JG |
1 | #ifndef _ASM_S390_JUMP_LABEL_H |
2 | #define _ASM_S390_JUMP_LABEL_H | |
3 | ||
55dd0df7 AB |
4 | #ifndef __ASSEMBLY__ |
5 | ||
5373db88 JG |
6 | #include <linux/types.h> |
7 | ||
8 | #define JUMP_LABEL_NOP_SIZE 6 | |
d5caa4db | 9 | #define JUMP_LABEL_NOP_OFFSET 2 |
5373db88 | 10 | |
d5caa4db HC |
11 | /* |
12 | * We use a brcl 0,2 instruction for jump labels at compile time so it | |
13 | * can be easily distinguished from a hotpatch generated instruction. | |
14 | */ | |
11276d53 | 15 | static __always_inline bool arch_static_branch(struct static_key *key, bool branch) |
5373db88 | 16 | { |
d5caa4db | 17 | asm_volatile_goto("0: brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n" |
5373db88 | 18 | ".pushsection __jump_table, \"aw\"\n" |
5a79859a HC |
19 | ".balign 8\n" |
20 | ".quad 0b, %l[label], %0\n" | |
5373db88 | 21 | ".popsection\n" |
11276d53 PZ |
22 | : : "X" (&((char *)key)[branch]) : : label); |
23 | ||
24 | return false; | |
25 | label: | |
26 | return true; | |
27 | } | |
28 | ||
29 | static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch) | |
30 | { | |
31 | asm_volatile_goto("0: brcl 15, %l[label]\n" | |
32 | ".pushsection __jump_table, \"aw\"\n" | |
33 | ".balign 8\n" | |
34 | ".quad 0b, %l[label], %0\n" | |
35 | ".popsection\n" | |
36 | : : "X" (&((char *)key)[branch]) : : label); | |
37 | ||
5373db88 JG |
38 | return false; |
39 | label: | |
40 | return true; | |
41 | } | |
42 | ||
43 | typedef unsigned long jump_label_t; | |
44 | ||
45 | struct jump_entry { | |
46 | jump_label_t code; | |
47 | jump_label_t target; | |
48 | jump_label_t key; | |
49 | }; | |
50 | ||
55dd0df7 | 51 | #endif /* __ASSEMBLY__ */ |
5373db88 | 52 | #endif |