include/linux/jump_label.h

   1 #ifndef _LINUX_JUMP_LABEL_H
   2 #define _LINUX_JUMP_LABEL_H
   3
   4 #include <linux/types.h>
   5 #include <linux/compiler.h>
   6
   7 #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
   8
   9 struct jump_label_key {
  10         atomic_t enabled;
  11         struct jump_entry *entries;
  12 #ifdef CONFIG_MODULES
  13         struct jump_label_mod *next;
  14 #endif
  15 };
  16
  17 # include <asm/jump_label.h>
  18 # define HAVE_JUMP_LABEL
  19 #endif
  20
  21 enum jump_label_type {
  22         JUMP_LABEL_DISABLE = 0,
  23         JUMP_LABEL_ENABLE,
  24 };
  25
  26 struct module;
  27
  28 #ifdef HAVE_JUMP_LABEL
  29
  30 #ifdef CONFIG_MODULES
  31 #define JUMP_LABEL_INIT {{ 0 }, NULL, NULL}
  32 #else
  33 #define JUMP_LABEL_INIT {{ 0 }, NULL}
  34 #endif
  35
  36 static __always_inline bool static_branch(struct jump_label_key *key)
  37 {
  38         return arch_static_branch(key);
  39 }
  40
  41 extern struct jump_entry __start___jump_table[];
  42 extern struct jump_entry __stop___jump_table[];
  43
  44 extern void jump_label_lock(void);
  45 extern void jump_label_unlock(void);
  46 extern void arch_jump_label_transform(struct jump_entry *entry,
  47                                  enum jump_label_type type);
  48 extern void arch_jump_label_text_poke_early(jump_label_t addr);
  49 extern int jump_label_text_reserved(void *start, void *end);
  50 extern void jump_label_inc(struct jump_label_key *key);
  51 extern void jump_label_dec(struct jump_label_key *key);
  52 extern bool jump_label_enabled(struct jump_label_key *key);
  53 extern void jump_label_apply_nops(struct module *mod);
  54
  55 #else
  56
  57 #include <linux/atomic.h>
  58
  59 #define JUMP_LABEL_INIT {ATOMIC_INIT(0)}
  60
  61 struct jump_label_key {
  62         atomic_t enabled;
  63 };
  64
  65 static __always_inline bool static_branch(struct jump_label_key *key)
  66 {
  67         if (unlikely(atomic_read(&key->enabled)))
  68                 return true;
  69         return false;
  70 }
  71
  72 static inline void jump_label_inc(struct jump_label_key *key)
  73 {
  74         atomic_inc(&key->enabled);
  75 }
  76
  77 static inline void jump_label_dec(struct jump_label_key *key)
  78 {
  79         atomic_dec(&key->enabled);
  80 }
  81
  82 static inline int jump_label_text_reserved(void *start, void *end)
  83 {
  84         return 0;
  85 }
  86
  87 static inline void jump_label_lock(void) {}
  88 static inline void jump_label_unlock(void) {}
  89
  90 static inline bool jump_label_enabled(struct jump_label_key *key)
  91 {
  92         return !!atomic_read(&key->enabled);
  93 }
  94
  95 static inline int jump_label_apply_nops(struct module *mod)
  96 {
  97         return 0;
  98 }
  99
 100 #endif
 101
 102 #endif