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_HAVE_ARCH_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 arch_jump_label_transform(struct jump_entry *entry,
  22                                  enum jump_label_type type);
  23 extern void arch_jump_label_text_poke_early(jump_label_t addr);
  24 extern void jump_label_update(unsigned long key, enum jump_label_type type);
  25 extern void jump_label_apply_nops(struct module *mod);
  26 extern int jump_label_text_reserved(void *start, void *end);
  27
  28 #define jump_label_enable(key) \
  29         jump_label_update((unsigned long)key, JUMP_LABEL_ENABLE);
  30
  31 #define jump_label_disable(key) \
  32         jump_label_update((unsigned long)key, JUMP_LABEL_DISABLE);
  33
  34 #else
  35
  36 #define JUMP_LABEL(key, label)                  \
  37 do {                                            \
  38         if (unlikely(*key))                     \
  39                 goto label;                     \
  40 } while (0)
  41
  42 #define jump_label_enable(cond_var)     \
  43 do {                                    \
  44        *(cond_var) = 1;                 \
  45 } while (0)
  46
  47 #define jump_label_disable(cond_var)    \
  48 do {                                    \
  49        *(cond_var) = 0;                 \
  50 } while (0)
  51
  52 static inline int jump_label_apply_nops(struct module *mod)
  53 {
  54         return 0;
  55 }
  56
  57 static inline int jump_label_text_reserved(void *start, void *end)
  58 {
  59         return 0;
  60 }
  61
  62 #endif
  63
  64 #define COND_STMT(key, stmt)                                    \
  65 do {                                                            \
  66         __label__ jl_enabled;                                   \
  67         JUMP_LABEL(key, jl_enabled);                            \
  68         if (0) {                                                \
  69 jl_enabled:                                                     \
  70                 stmt;                                           \
  71         }                                                       \
  72 } while (0)
  73
  74 #endif