xref: /openbmc/linux/arch/x86/include/asm/jump_label.h (revision 94588c1b)
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 #define JUMP_LABEL_NOP_SIZE 5
8 
9 #include <asm/asm.h>
10 #include <asm/nops.h>
11 
12 #ifndef __ASSEMBLY__
13 
14 #include <linux/stringify.h>
15 #include <linux/types.h>
16 
17 static __always_inline bool arch_static_branch(struct static_key * const key, const bool branch)
18 {
19 	asm_volatile_goto("1:"
20 		".byte " __stringify(BYTES_NOP5) "\n\t"
21 		".pushsection __jump_table,  \"aw\" \n\t"
22 		_ASM_ALIGN "\n\t"
23 		".long 1b - ., %l[l_yes] - . \n\t"
24 		_ASM_PTR "%c0 + %c1 - .\n\t"
25 		".popsection \n\t"
26 		: :  "i" (key), "i" (branch) : : l_yes);
27 
28 	return false;
29 l_yes:
30 	return true;
31 }
32 
33 static __always_inline bool arch_static_branch_jump(struct static_key * const key, const bool branch)
34 {
35 	asm_volatile_goto("1:"
36 		".byte 0xe9\n\t .long %l[l_yes] - 2f\n\t"
37 		"2:\n\t"
38 		".pushsection __jump_table,  \"aw\" \n\t"
39 		_ASM_ALIGN "\n\t"
40 		".long 1b - ., %l[l_yes] - . \n\t"
41 		_ASM_PTR "%c0 + %c1 - .\n\t"
42 		".popsection \n\t"
43 		: :  "i" (key), "i" (branch) : : l_yes);
44 
45 	return false;
46 l_yes:
47 	return true;
48 }
49 
50 #else	/* __ASSEMBLY__ */
51 
52 .macro STATIC_JUMP_IF_TRUE target, key, def
53 .Lstatic_jump_\@:
54 	.if \def
55 	/* Equivalent to "jmp.d32 \target" */
56 	.byte		0xe9
57 	.long		\target - .Lstatic_jump_after_\@
58 .Lstatic_jump_after_\@:
59 	.else
60 	.byte		BYTES_NOP5
61 	.endif
62 	.pushsection __jump_table, "aw"
63 	_ASM_ALIGN
64 	.long		.Lstatic_jump_\@ - ., \target - .
65 	_ASM_PTR	\key - .
66 	.popsection
67 .endm
68 
69 .macro STATIC_JUMP_IF_FALSE target, key, def
70 .Lstatic_jump_\@:
71 	.if \def
72 	.byte		BYTES_NOP5
73 	.else
74 	/* Equivalent to "jmp.d32 \target" */
75 	.byte		0xe9
76 	.long		\target - .Lstatic_jump_after_\@
77 .Lstatic_jump_after_\@:
78 	.endif
79 	.pushsection __jump_table, "aw"
80 	_ASM_ALIGN
81 	.long		.Lstatic_jump_\@ - ., \target - .
82 	_ASM_PTR	\key + 1 - .
83 	.popsection
84 .endm
85 
86 #endif	/* __ASSEMBLY__ */
87 
88 #endif
89