xref: /linux/arch/arm/include/asm/jump_label.h (revision 7f71507851fc7764b36a3221839607d3a45c2025)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_ARM_JUMP_LABEL_H
3 #define _ASM_ARM_JUMP_LABEL_H
4 
5 #ifndef __ASSEMBLY__
6 
7 #include <linux/types.h>
8 #include <asm/unified.h>
9 
10 #define JUMP_LABEL_NOP_SIZE 4
11 
12 /* This macro is also expanded on the Rust side. */
13 #define ARCH_STATIC_BRANCH_ASM(key, label)		\
14 	"1:\n\t"					\
15 	WASM(nop) "\n\t"				\
16 	".pushsection __jump_table,  \"aw\"\n\t"	\
17 	".word 1b, " label ", " key "\n\t"		\
18 	".popsection\n\t"				\
19 
20 static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
21 {
22 	asm goto(ARCH_STATIC_BRANCH_ASM("%c0", "%l[l_yes]")
23 		 : :  "i" (&((char *)key)[branch]) :  : l_yes);
24 
25 	return false;
26 l_yes:
27 	return true;
28 }
29 
30 static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)
31 {
32 	asm goto("1:\n\t"
33 		 WASM(b) " %l[l_yes]\n\t"
34 		 ".pushsection __jump_table,  \"aw\"\n\t"
35 		 ".word 1b, %l[l_yes], %c0\n\t"
36 		 ".popsection\n\t"
37 		 : :  "i" (&((char *)key)[branch]) :  : l_yes);
38 
39 	return false;
40 l_yes:
41 	return true;
42 }
43 
44 typedef u32 jump_label_t;
45 
46 struct jump_entry {
47 	jump_label_t code;
48 	jump_label_t target;
49 	jump_label_t key;
50 };
51 
52 #endif  /* __ASSEMBLY__ */
53 #endif
54