1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_S390_JUMP_LABEL_H
3 #define _ASM_S390_JUMP_LABEL_H
4
5 #define HAVE_JUMP_LABEL_BATCH
6
7 #ifndef __ASSEMBLY__
8
9 #include <linux/types.h>
10 #include <linux/stringify.h>
11
12 #define JUMP_LABEL_NOP_SIZE 6
13 #define JUMP_LABEL_NOP_OFFSET 2
14
15 #ifdef CONFIG_CC_IS_CLANG
16 #define JUMP_LABEL_STATIC_KEY_CONSTRAINT "i"
17 #elif __GNUC__ < 9
18 #define JUMP_LABEL_STATIC_KEY_CONSTRAINT "X"
19 #else
20 #define JUMP_LABEL_STATIC_KEY_CONSTRAINT "jdd"
21 #endif
22
23 /*
24 * We use a brcl 0,2 instruction for jump labels at compile time so it
25 * can be easily distinguished from a hotpatch generated instruction.
26 */
arch_static_branch(struct static_key * key,bool branch)27 static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
28 {
29 asm_volatile_goto("0: brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n"
30 ".pushsection __jump_table,\"aw\"\n"
31 ".balign 8\n"
32 ".long 0b-.,%l[label]-.\n"
33 ".quad %0+%1-.\n"
34 ".popsection\n"
35 : : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label);
36 return false;
37 label:
38 return true;
39 }
40
arch_static_branch_jump(struct static_key * key,bool branch)41 static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)
42 {
43 asm_volatile_goto("0: brcl 15,%l[label]\n"
44 ".pushsection __jump_table,\"aw\"\n"
45 ".balign 8\n"
46 ".long 0b-.,%l[label]-.\n"
47 ".quad %0+%1-.\n"
48 ".popsection\n"
49 : : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label);
50 return false;
51 label:
52 return true;
53 }
54
55 #endif /* __ASSEMBLY__ */
56 #endif
57