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
14 #ifdef CONFIG_CC_IS_CLANG
15 #define JUMP_LABEL_STATIC_KEY_CONSTRAINT "i"
16 #elif __GNUC__ < 9
17 #define JUMP_LABEL_STATIC_KEY_CONSTRAINT "X"
18 #else
19 #define JUMP_LABEL_STATIC_KEY_CONSTRAINT "jdd"
20 #endif
21
22 /*
23 * We use a brcl 0,<offset> instruction for jump labels so it
24 * can be easily distinguished from a hotpatch generated instruction.
25 */
26 static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
27 {
28 asm goto("0: brcl 0,%l[label]\n"
29 ".pushsection __jump_table,\"aw\"\n"
30 ".balign 8\n"
31 ".long 0b-.,%l[label]-.\n"
32 ".quad %0+%1-.\n"
33 ".popsection\n"
34 : : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label);
35 return false;
36 label:
37 return true;
38 }
39
40 static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)
41 {
42 asm goto("0: brcl 15,%l[label]\n"
43 ".pushsection __jump_table,\"aw\"\n"
44 ".balign 8\n"
45 ".long 0b-.,%l[label]-.\n"
46 ".quad %0+%1-.\n"
47 ".popsection\n"
48 : : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label);
49 return false;
50 label:
51 return true;
52 }
53
54 #endif /* __ASSEMBLY__ */
55 #endif
56
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