arch/x86/include/asm/jump_label.h

   1 #ifndef _ASM_X86_JUMP_LABEL_H
   2 #define _ASM_X86_JUMP_LABEL_H
   3
   4 #ifndef __ASSEMBLY__
   5
   6 #include <linux/stringify.h>
   7 #include <linux/types.h>
   8 #include <asm/nops.h>
   9 #include <asm/asm.h>
  10
  11 #define JUMP_LABEL_NOP_SIZE 5
  12
  13 #ifdef CONFIG_X86_64
  14 # define STATIC_KEY_INIT_NOP P6_NOP5_ATOMIC
  15 #else
  16 # define STATIC_KEY_INIT_NOP GENERIC_NOP5_ATOMIC
  17 #endif
  18
  19 static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
  20 {
  21         asm_volatile_goto("1:"
  22                 ".byte " __stringify(STATIC_KEY_INIT_NOP) "\n\t"
  23                 ".pushsection __jump_table,  \"aw\" \n\t"
  24                 _ASM_ALIGN "\n\t"
  25                 _ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t"
  26                 ".popsection \n\t"
  27                 : :  "i" (key), "i" (branch) : : l_yes);
  28
  29         return false;
  30 l_yes:
  31         return true;
  32 }
  33
  34 static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)
  35 {
  36         asm_volatile_goto("1:"
  37                 ".byte 0xe9\n\t .long %l[l_yes] - 2f\n\t"
  38                 "2:\n\t"
  39                 ".pushsection __jump_table,  \"aw\" \n\t"
  40                 _ASM_ALIGN "\n\t"
  41                 _ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t"
  42                 ".popsection \n\t"
  43                 : :  "i" (key), "i" (branch) : : l_yes);
  44
  45         return false;
  46 l_yes:
  47         return true;
  48 }
  49
  50 #ifdef CONFIG_X86_64
  51 typedef u64 jump_label_t;
  52 #else
  53 typedef u32 jump_label_t;
  54 #endif
  55
  56 struct jump_entry {
  57         jump_label_t code;
  58         jump_label_t target;
  59         jump_label_t key;
  60 };
  61
  62 #endif  /* __ASSEMBLY__ */
  63 #endif