arch/x86/include/asm/jump_label.h

   1 #ifndef _ASM_X86_JUMP_LABEL_H
   2 #define _ASM_X86_JUMP_LABEL_H
   3
   4 #ifdef __KERNEL__
   5
   6 #include <linux/types.h>
   7 #include <asm/nops.h>
   8 #include <asm/asm.h>
   9
  10 #define JUMP_LABEL_NOP_SIZE 5
  11
  12 #define JUMP_LABEL_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t"
  13
  14 static __always_inline bool arch_static_branch(struct jump_label_key *key)
  15 {
  16         asm goto("1:"
  17                 JUMP_LABEL_INITIAL_NOP
  18                 ".pushsection __jump_table,  \"aw\" \n\t"
  19                 _ASM_PTR "1b, %l[l_yes], %c0 \n\t"
  20                 ".popsection \n\t"
  21                 : :  "i" (key) : : l_yes);
  22         return false;
  23 l_yes:
  24         return true;
  25 }
  26
  27 #endif /* __KERNEL__ */
  28
  29 #ifdef CONFIG_X86_64
  30 typedef u64 jump_label_t;
  31 #else
  32 typedef u32 jump_label_t;
  33 #endif
  34
  35 struct jump_entry {
  36         jump_label_t code;
  37         jump_label_t target;
  38         jump_label_t key;
  39 };
  40
  41 #endif