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