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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
d9f5ab7b JB |
2 | #ifndef _ASM_X86_JUMP_LABEL_H |
3 | #define _ASM_X86_JUMP_LABEL_H | |
4 | ||
c2845433 AL |
5 | #ifndef HAVE_JUMP_LABEL |
6 | /* | |
7 | * For better or for worse, if jump labels (the gcc extension) are missing, | |
8 | * then the entire static branch patching infrastructure is compiled out. | |
9 | * If that happens, the code in here will malfunction. Raise a compiler | |
10 | * error instead. | |
11 | * | |
12 | * In theory, jump labels and the static branch patching infrastructure | |
13 | * could be decoupled to fix this. | |
14 | */ | |
15 | #error asm/jump_label.h included on a non-jump-label kernel | |
16 | #endif | |
17 | ||
d9f5ab7b JB |
18 | #define JUMP_LABEL_NOP_SIZE 5 |
19 | ||
c3c7f14a SR |
20 | #ifdef CONFIG_X86_64 |
21 | # define STATIC_KEY_INIT_NOP P6_NOP5_ATOMIC | |
22 | #else | |
23 | # define STATIC_KEY_INIT_NOP GENERIC_NOP5_ATOMIC | |
24 | #endif | |
d430d3d7 | 25 | |
2671c3e4 AL |
26 | #include <asm/asm.h> |
27 | #include <asm/nops.h> | |
28 | ||
29 | #ifndef __ASSEMBLY__ | |
30 | ||
31 | #include <linux/stringify.h> | |
32 | #include <linux/types.h> | |
33 | ||
11276d53 | 34 | static __always_inline bool arch_static_branch(struct static_key *key, bool branch) |
d430d3d7 | 35 | { |
3f0116c3 | 36 | asm_volatile_goto("1:" |
c3c7f14a | 37 | ".byte " __stringify(STATIC_KEY_INIT_NOP) "\n\t" |
d430d3d7 | 38 | ".pushsection __jump_table, \"aw\" \n\t" |
ef647894 | 39 | _ASM_ALIGN "\n\t" |
d420acd8 | 40 | _ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t" |
d430d3d7 | 41 | ".popsection \n\t" |
d420acd8 | 42 | : : "i" (key), "i" (branch) : : l_yes); |
11276d53 PZ |
43 | |
44 | return false; | |
45 | l_yes: | |
46 | return true; | |
47 | } | |
48 | ||
49 | static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch) | |
50 | { | |
51 | asm_volatile_goto("1:" | |
52 | ".byte 0xe9\n\t .long %l[l_yes] - 2f\n\t" | |
53 | "2:\n\t" | |
54 | ".pushsection __jump_table, \"aw\" \n\t" | |
55 | _ASM_ALIGN "\n\t" | |
d420acd8 | 56 | _ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t" |
11276d53 | 57 | ".popsection \n\t" |
d420acd8 | 58 | : : "i" (key), "i" (branch) : : l_yes); |
11276d53 | 59 | |
d430d3d7 JB |
60 | return false; |
61 | l_yes: | |
62 | return true; | |
63 | } | |
d9f5ab7b | 64 | |
d9f5ab7b | 65 | #ifdef CONFIG_X86_64 |
d9f5ab7b | 66 | typedef u64 jump_label_t; |
d9f5ab7b | 67 | #else |
d9f5ab7b | 68 | typedef u32 jump_label_t; |
95fccd46 | 69 | #endif |
d9f5ab7b JB |
70 | |
71 | struct jump_entry { | |
72 | jump_label_t code; | |
73 | jump_label_t target; | |
74 | jump_label_t key; | |
75 | }; | |
76 | ||
2671c3e4 AL |
77 | #else /* __ASSEMBLY__ */ |
78 | ||
79 | .macro STATIC_JUMP_IF_TRUE target, key, def | |
80 | .Lstatic_jump_\@: | |
81 | .if \def | |
82 | /* Equivalent to "jmp.d32 \target" */ | |
83 | .byte 0xe9 | |
84 | .long \target - .Lstatic_jump_after_\@ | |
85 | .Lstatic_jump_after_\@: | |
86 | .else | |
87 | .byte STATIC_KEY_INIT_NOP | |
88 | .endif | |
89 | .pushsection __jump_table, "aw" | |
90 | _ASM_ALIGN | |
91 | _ASM_PTR .Lstatic_jump_\@, \target, \key | |
92 | .popsection | |
93 | .endm | |
94 | ||
95 | .macro STATIC_JUMP_IF_FALSE target, key, def | |
96 | .Lstatic_jump_\@: | |
97 | .if \def | |
98 | .byte STATIC_KEY_INIT_NOP | |
99 | .else | |
100 | /* Equivalent to "jmp.d32 \target" */ | |
101 | .byte 0xe9 | |
102 | .long \target - .Lstatic_jump_after_\@ | |
103 | .Lstatic_jump_after_\@: | |
104 | .endif | |
105 | .pushsection __jump_table, "aw" | |
106 | _ASM_ALIGN | |
107 | _ASM_PTR .Lstatic_jump_\@, \target, \key + 1 | |
108 | .popsection | |
109 | .endm | |
110 | ||
111 | #endif /* __ASSEMBLY__ */ | |
112 | ||
d9f5ab7b | 113 | #endif |