root/arch/s390/include/asm/jump_label.h
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_S390_JUMP_LABEL_H
#define _ASM_S390_JUMP_LABEL_H

#define HAVE_JUMP_LABEL_BATCH

#ifndef __ASSEMBLER__

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

#define JUMP_LABEL_NOP_SIZE 6

#ifdef CONFIG_CC_IS_CLANG
#define JUMP_LABEL_STATIC_KEY_CONSTRAINT "i"
#elif __GNUC__ < 9
#define JUMP_LABEL_STATIC_KEY_CONSTRAINT "X"
#else
#define JUMP_LABEL_STATIC_KEY_CONSTRAINT "jdd"
#endif

#define ARCH_JUMP_TABLE_ENTRY(key, label, local_label)  \
        ".pushsection __jump_table,\"aw\"\n"            \
        ".balign        8\n"                            \
        ".long  " local_label "-.," label "-.\n"        \
        ".quad  " key "-.\n"                            \
        ".popsection\n"

/*
 * We use a brcl 0,<offset> instruction for jump labels so it
 * can be easily distinguished from a hotpatch generated instruction.
 */
#define ARCH_STATIC_BRANCH_ASM(key, label)      \
        "0:     brcl 0," label "\n"             \
        ARCH_JUMP_TABLE_ENTRY(key, label, "0b")

#define ARCH_STATIC_BRANCH_JUMP_ASM(key, label) \
        "0:     brcl 15," label "\n"            \
        ARCH_JUMP_TABLE_ENTRY(key, label, "0b")

static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
{
        asm goto(ARCH_STATIC_BRANCH_ASM("%0+%1", "%l[label]")
                : : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label);
        return false;
label:
        return true;
}

static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)
{
        asm goto(ARCH_STATIC_BRANCH_JUMP_ASM("%0+%1", "%l[label]")
                : : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label);
        return false;
label:
        return true;
}

#endif  /* __ASSEMBLER__ */
#endif