xref: /openbmc/linux/arch/x86/include/asm/jump_label.h (revision c34a8052)
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 __ASSEMBLY__
11 
12 #include <linux/stringify.h>
13 #include <linux/types.h>
14 
15 #define JUMP_TABLE_ENTRY				\
16 	".pushsection __jump_table,  \"aw\" \n\t"	\
17 	_ASM_ALIGN "\n\t"				\
18 	".long 1b - . \n\t"				\
19 	".long %l[l_yes] - . \n\t"			\
20 	_ASM_PTR "%c0 + %c1 - .\n\t"			\
21 	".popsection \n\t"
22 
23 #ifdef CONFIG_HAVE_JUMP_LABEL_HACK
24 
25 static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
26 {
27 	asm goto("1:"
28 		"jmp %l[l_yes] # objtool NOPs this \n\t"
29 		JUMP_TABLE_ENTRY
30 		: :  "i" (key), "i" (2 | branch) : : l_yes);
31 
32 	return false;
33 l_yes:
34 	return true;
35 }
36 
37 #else /* !CONFIG_HAVE_JUMP_LABEL_HACK */
38 
39 static __always_inline bool arch_static_branch(struct static_key * const key, const bool branch)
40 {
41 	asm goto("1:"
42 		".byte " __stringify(BYTES_NOP5) "\n\t"
43 		JUMP_TABLE_ENTRY
44 		: :  "i" (key), "i" (branch) : : l_yes);
45 
46 	return false;
47 l_yes:
48 	return true;
49 }
50 
51 #endif /* CONFIG_HAVE_JUMP_LABEL_HACK */
52 
53 static __always_inline bool arch_static_branch_jump(struct static_key * const key, const bool branch)
54 {
55 	asm goto("1:"
56 		"jmp %l[l_yes]\n\t"
57 		JUMP_TABLE_ENTRY
58 		: :  "i" (key), "i" (branch) : : l_yes);
59 
60 	return false;
61 l_yes:
62 	return true;
63 }
64 
65 extern int arch_jump_entry_size(struct jump_entry *entry);
66 
67 #endif	/* __ASSEMBLY__ */
68 
69 #endif
70