LXR linux/arch/s390/include/asm/jump

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