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v0.8.1
https://github.com/torvalds/linux
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Tip revision: a3b22b9f11d9fbc48b0291ea92259a5a810e9438 authored by Linus Torvalds on 18 February 2019, 02:46:40 UTC
Linux 5.0-rc7
Tip revision: a3b22b9
jump_label.h
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_S390_JUMP_LABEL_H
#define _ASM_S390_JUMP_LABEL_H

#ifndef __ASSEMBLY__

#include <linux/types.h>
#include <linux/stringify.h>

#define JUMP_LABEL_NOP_SIZE 6
#define JUMP_LABEL_NOP_OFFSET 2

/*
 * We use a brcl 0,2 instruction for jump labels at compile time so it
 * can be easily distinguished from a hotpatch generated instruction.
 */
static inline bool arch_static_branch(struct static_key *key, bool branch)
{
	asm_volatile_goto("0:	brcl	0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n"
			  ".pushsection __jump_table,\"aw\"\n"
			  ".balign	8\n"
			  ".long	0b-.,%l[label]-.\n"
			  ".quad	%0-.\n"
			  ".popsection\n"
			  : : "X" (&((char *)key)[branch]) : : label);
	return false;
label:
	return true;
}

static inline bool arch_static_branch_jump(struct static_key *key, bool branch)
{
	asm_volatile_goto("0:	brcl 15,%l[label]\n"
			  ".pushsection __jump_table,\"aw\"\n"
			  ".balign	8\n"
			  ".long	0b-.,%l[label]-.\n"
			  ".quad	%0-.\n"
			  ".popsection\n"
			  : : "X" (&((char *)key)[branch]) : : label);
	return false;
label:
	return true;
}

#endif  /* __ASSEMBLY__ */
#endif
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