arch/s390/include/asm/jump_label.h

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