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 #include <linux/workqueue.h>
   7
   8 #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
   9
  10 struct jump_label_key {
  11         atomic_t enabled;
  12         struct jump_entry *entries;
  13 #ifdef CONFIG_MODULES
  14         struct jump_label_mod *next;
  15 #endif
  16 };
  17
  18 struct jump_label_key_deferred {
  19         struct jump_label_key key;
  20         unsigned long timeout;
  21         struct delayed_work work;
  22 };
  23
  24 # include <asm/jump_label.h>
  25 # define HAVE_JUMP_LABEL
  26 #endif  /* CC_HAVE_ASM_GOTO && CONFIG_JUMP_LABEL */
  27
  28 enum jump_label_type {
  29         JUMP_LABEL_DISABLE = 0,
  30         JUMP_LABEL_ENABLE,
  31 };
  32
  33 struct module;
  34
  35 #ifdef HAVE_JUMP_LABEL
  36
  37 #ifdef CONFIG_MODULES
  38 #define JUMP_LABEL_INIT {ATOMIC_INIT(0), NULL, NULL}
  39 #else
  40 #define JUMP_LABEL_INIT {ATOMIC_INIT(0), NULL}
  41 #endif
  42
  43 static __always_inline bool static_branch(struct jump_label_key *key)
  44 {
  45         return arch_static_branch(key);
  46 }
  47
  48 extern struct jump_entry __start___jump_table[];
  49 extern struct jump_entry __stop___jump_table[];
  50
  51 extern void jump_label_init(void);
  52 extern void jump_label_lock(void);
  53 extern void jump_label_unlock(void);
  54 extern void arch_jump_label_transform(struct jump_entry *entry,
  55                                       enum jump_label_type type);
  56 extern void arch_jump_label_transform_static(struct jump_entry *entry,
  57                                              enum jump_label_type type);
  58 extern int jump_label_text_reserved(void *start, void *end);
  59 extern void jump_label_inc(struct jump_label_key *key);
  60 extern void jump_label_dec(struct jump_label_key *key);
  61 extern void jump_label_dec_deferred(struct jump_label_key_deferred *key);
  62 extern bool jump_label_enabled(struct jump_label_key *key);
  63 extern void jump_label_apply_nops(struct module *mod);
  64 extern void jump_label_rate_limit(struct jump_label_key_deferred *key,
  65                 unsigned long rl);
  66
  67 #else  /* !HAVE_JUMP_LABEL */
  68
  69 #include <linux/atomic.h>
  70
  71 #define JUMP_LABEL_INIT {ATOMIC_INIT(0)}
  72
  73 struct jump_label_key {
  74         atomic_t enabled;
  75 };
  76
  77 static __always_inline void jump_label_init(void)
  78 {
  79 }
  80
  81 struct jump_label_key_deferred {
  82         struct jump_label_key  key;
  83 };
  84
  85 static __always_inline bool static_branch(struct jump_label_key *key)
  86 {
  87         if (unlikely(atomic_read(&key->enabled)))
  88                 return true;
  89         return false;
  90 }
  91
  92 static inline void jump_label_inc(struct jump_label_key *key)
  93 {
  94         atomic_inc(&key->enabled);
  95 }
  96
  97 static inline void jump_label_dec(struct jump_label_key *key)
  98 {
  99         atomic_dec(&key->enabled);
 100 }
 101
 102 static inline void jump_label_dec_deferred(struct jump_label_key_deferred *key)
 103 {
 104         jump_label_dec(&key->key);
 105 }
 106
 107 static inline int jump_label_text_reserved(void *start, void *end)
 108 {
 109         return 0;
 110 }
 111
 112 static inline void jump_label_lock(void) {}
 113 static inline void jump_label_unlock(void) {}
 114
 115 static inline bool jump_label_enabled(struct jump_label_key *key)
 116 {
 117         return !!atomic_read(&key->enabled);
 118 }
 119
 120 static inline int jump_label_apply_nops(struct module *mod)
 121 {
 122         return 0;
 123 }
 124
 125 static inline void jump_label_rate_limit(struct jump_label_key_deferred *key,
 126                 unsigned long rl)
 127 {
 128 }
 129 #endif  /* HAVE_JUMP_LABEL */
 130
 131 #define jump_label_key_enabled  ((struct jump_label_key){ .enabled = ATOMIC_INIT(1), })
 132 #define jump_label_key_disabled ((struct jump_label_key){ .enabled = ATOMIC_INIT(0), })
 133
 134 #endif  /* _LINUX_JUMP_LABEL_H */