arch/s390/include/asm/jump_label.h

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