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 STATIC_KEY_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t"
  13
  14 static __always_inline bool arch_static_branch(struct static_key *key)
  15 {
  16         asm goto("1:"
  17                 STATIC_KEY_INITIAL_NOP
  18                 ".pushsection __jump_table,  \"aw\" \n\t"
  19                 _ASM_ALIGN "\n\t"
  20                 _ASM_PTR "1b, %l[l_yes], %c0 \n\t"
  21                 ".popsection \n\t"
  22                 : :  "i" (key) : : l_yes);
  23         return false;
  24 l_yes:
  25         return true;
  26 }
  27
  28 #endif /* __KERNEL__ */
  29
  30 #ifdef CONFIG_X86_64
  31 typedef u64 jump_label_t;
  32 #else
  33 typedef u32 jump_label_t;
  34 #endif
  35
  36 struct jump_entry {
  37         jump_label_t code;
  38         jump_label_t target;
  39         jump_label_t key;
  40 };
  41
  42 #endif