arch/riscv/include/asm/jump_label.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2020 Emil Renner Berthing
   4  *
   5  * Based on arch/arm64/include/asm/jump_label.h
   6  */
   7 #ifndef __ASM_JUMP_LABEL_H
   8 #define __ASM_JUMP_LABEL_H
   9
  10 #ifndef __ASSEMBLY__
  11
  12 #include <linux/types.h>
  13 #include <asm/asm.h>
  14
  15 #define JUMP_LABEL_NOP_SIZE 4
  16
  17 static __always_inline bool arch_static_branch(struct static_key * const key,
  18                                                const bool branch)
  19 {
  20         asm goto(
  21                 "       .align          2                       \n\t"
  22                 "       .option push                            \n\t"
  23                 "       .option norelax                         \n\t"
  24                 "       .option norvc                           \n\t"
  25                 "1:     nop                                     \n\t"
  26                 "       .option pop                             \n\t"
  27                 "       .pushsection    __jump_table, \"aw\"    \n\t"
  28                 "       .align          " RISCV_LGPTR "         \n\t"
  29                 "       .long           1b - ., %l[label] - .   \n\t"
  30                 "       " RISCV_PTR "   %0 - .                  \n\t"
  31                 "       .popsection                             \n\t"
  32                 :  :  "i"(&((char *)key)[branch]) :  : label);
  33
  34         return false;
  35 label:
  36         return true;
  37 }
  38
  39 static __always_inline bool arch_static_branch_jump(struct static_key * const key,
  40                                                     const bool branch)
  41 {
  42         asm goto(
  43                 "       .align          2                       \n\t"
  44                 "       .option push                            \n\t"
  45                 "       .option norelax                         \n\t"
  46                 "       .option norvc                           \n\t"
  47                 "1:     jal             zero, %l[label]         \n\t"
  48                 "       .option pop                             \n\t"
  49                 "       .pushsection    __jump_table, \"aw\"    \n\t"
  50                 "       .align          " RISCV_LGPTR "         \n\t"
  51                 "       .long           1b - ., %l[label] - .   \n\t"
  52                 "       " RISCV_PTR "   %0 - .                  \n\t"
  53                 "       .popsection                             \n\t"
  54                 :  :  "i"(&((char *)key)[branch]) :  : label);
  55
  56         return false;
  57 label:
  58         return true;
  59 }
  60
  61 #endif  /* __ASSEMBLY__ */
  62 #endif  /* __ASM_JUMP_LABEL_H */