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  /* CC_HAVE_ASM_GOTO && CONFIG_JUMP_LABEL */
  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 {ATOMIC_INIT(0), NULL, NULL}
  32 #else
  33 #define JUMP_LABEL_INIT {ATOMIC_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_init(void);
  45 extern void jump_label_lock(void);
  46 extern void jump_label_unlock(void);
  47 extern void arch_jump_label_transform(struct jump_entry *entry,
  48                                       enum jump_label_type type);
  49 extern void arch_jump_label_transform_static(struct jump_entry *entry,
  50                                              enum jump_label_type type);
  51 extern int jump_label_text_reserved(void *start, void *end);
  52 extern void jump_label_inc(struct jump_label_key *key);
  53 extern void jump_label_dec(struct jump_label_key *key);
  54 extern bool jump_label_enabled(struct jump_label_key *key);
  55 extern void jump_label_apply_nops(struct module *mod);
  56
  57 #else  /* !HAVE_JUMP_LABEL */
  58
  59 #include <linux/atomic.h>
  60
  61 #define JUMP_LABEL_INIT {ATOMIC_INIT(0)}
  62
  63 struct jump_label_key {
  64         atomic_t enabled;
  65 };
  66
  67 static __always_inline void jump_label_init(void)
  68 {
  69 }
  70
  71 static __always_inline bool static_branch(struct jump_label_key *key)
  72 {
  73         if (unlikely(atomic_read(&key->enabled)))
  74                 return true;
  75         return false;
  76 }
  77
  78 static inline void jump_label_inc(struct jump_label_key *key)
  79 {
  80         atomic_inc(&key->enabled);
  81 }
  82
  83 static inline void jump_label_dec(struct jump_label_key *key)
  84 {
  85         atomic_dec(&key->enabled);
  86 }
  87
  88 static inline int jump_label_text_reserved(void *start, void *end)
  89 {
  90         return 0;
  91 }
  92
  93 static inline void jump_label_lock(void) {}
  94 static inline void jump_label_unlock(void) {}
  95
  96 static inline bool jump_label_enabled(struct jump_label_key *key)
  97 {
  98         return !!atomic_read(&key->enabled);
  99 }
 100
 101 static inline int jump_label_apply_nops(struct module *mod)
 102 {
 103         return 0;
 104 }
 105 #endif  /* HAVE_JUMP_LABEL */
 106
 107 #endif  /* _LINUX_JUMP_LABEL_H */