include/linux/jump_label.h

   1 #ifndef _LINUX_JUMP_LABEL_H
   2 #define _LINUX_JUMP_LABEL_H
   3
   4 #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
   5 # include <asm/jump_label.h>
   6 # define HAVE_JUMP_LABEL
   7 #endif
   8
   9 enum jump_label_type {
  10         JUMP_LABEL_ENABLE,
  11         JUMP_LABEL_DISABLE
  12 };
  13
  14 struct module;
  15
  16 #ifdef HAVE_JUMP_LABEL
  17
  18 extern struct jump_entry __start___jump_table[];
  19 extern struct jump_entry __stop___jump_table[];
  20
  21 extern void jump_label_lock(void);
  22 extern void jump_label_unlock(void);
  23 extern void arch_jump_label_transform(struct jump_entry *entry,
  24                                  enum jump_label_type type);
  25 extern void arch_jump_label_text_poke_early(jump_label_t addr);
  26 extern void jump_label_update(unsigned long key, enum jump_label_type type);
  27 extern void jump_label_apply_nops(struct module *mod);
  28 extern int jump_label_text_reserved(void *start, void *end);
  29
  30 #define jump_label_enable(key) \
  31         jump_label_update((unsigned long)key, JUMP_LABEL_ENABLE);
  32
  33 #define jump_label_disable(key) \
  34         jump_label_update((unsigned long)key, JUMP_LABEL_DISABLE);
  35
  36 #else
  37
  38 #define JUMP_LABEL(key, label)                  \
  39 do {                                            \
  40         if (unlikely(*key))                     \
  41                 goto label;                     \
  42 } while (0)
  43
  44 #define jump_label_enable(cond_var)     \
  45 do {                                    \
  46        *(cond_var) = 1;                 \
  47 } while (0)
  48
  49 #define jump_label_disable(cond_var)    \
  50 do {                                    \
  51        *(cond_var) = 0;                 \
  52 } while (0)
  53
  54 static inline int jump_label_apply_nops(struct module *mod)
  55 {
  56         return 0;
  57 }
  58
  59 static inline int jump_label_text_reserved(void *start, void *end)
  60 {
  61         return 0;
  62 }
  63
  64 static inline void jump_label_lock(void) {}
  65 static inline void jump_label_unlock(void) {}
  66
  67 #endif
  68
  69 #define COND_STMT(key, stmt)                                    \
  70 do {                                                            \
  71         __label__ jl_enabled;                                   \
  72         JUMP_LABEL(key, jl_enabled);                            \
  73         if (0) {                                                \
  74 jl_enabled:                                                     \
  75                 stmt;                                           \
  76         }                                                       \
  77 } while (0)
  78
  79 #endif