arch/arm64/include/asm/jump_label.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2013 Huawei Ltd.
   4  * Author: Jiang Liu <liuj97@gmail.com>
   5  *
   6  * Based on arch/arm/include/asm/jump_label.h
   7  */
   8 #ifndef __ASM_JUMP_LABEL_H
   9 #define __ASM_JUMP_LABEL_H
  10
  11 #ifndef __ASSEMBLY__
  12
  13 #include <linux/types.h>
  14 #include <asm/insn.h>
  15
  16 #define HAVE_JUMP_LABEL_BATCH
  17 #define JUMP_LABEL_NOP_SIZE             AARCH64_INSN_SIZE
  18
  19 #define JUMP_TABLE_ENTRY(key, label)                    \
  20         ".pushsection   __jump_table, \"aw\"\n\t"       \
  21         ".align         3\n\t"                          \
  22         ".long          1b - ., " label " - .\n\t"      \
  23         ".quad          " key " - .\n\t"                \
  24         ".popsection\n\t"
  25
  26 /* This macro is also expanded on the Rust side. */
  27 #define ARCH_STATIC_BRANCH_ASM(key, label)              \
  28         "1:     nop\n\t"                                \
  29         JUMP_TABLE_ENTRY(key, label)
  30
  31 static __always_inline bool arch_static_branch(struct static_key * const key,
  32                                                const bool branch)
  33 {
  34         char *k = &((char *)key)[branch];
  35
  36         asm goto(
  37                 ARCH_STATIC_BRANCH_ASM("%c0", "%l[l_yes]")
  38                 :  :  "i"(k) :  : l_yes
  39                 );
  40
  41         return false;
  42 l_yes:
  43         return true;
  44 }
  45
  46 static __always_inline bool arch_static_branch_jump(struct static_key * const key,
  47                                                     const bool branch)
  48 {
  49         char *k = &((char *)key)[branch];
  50
  51         asm goto(
  52                 "1:     b               %l[l_yes]               \n\t"
  53                 JUMP_TABLE_ENTRY("%c0", "%l[l_yes]")
  54                 :  :  "i"(k) :  : l_yes
  55                 );
  56         return false;
  57 l_yes:
  58         return true;
  59 }
  60
  61 #endif  /* __ASSEMBLY__ */
  62 #endif  /* __ASM_JUMP_LABEL_H */