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Diffstat (limited to 'ANDROID_3.4.5/include/linux/jump_label.h')
| -rw-r--r-- | ANDROID_3.4.5/include/linux/jump_label.h | 226 |
1 files changed, 0 insertions, 226 deletions
diff --git a/ANDROID_3.4.5/include/linux/jump_label.h b/ANDROID_3.4.5/include/linux/jump_label.h deleted file mode 100644 index c513a405..00000000 --- a/ANDROID_3.4.5/include/linux/jump_label.h +++ /dev/null @@ -1,226 +0,0 @@ -#ifndef _LINUX_JUMP_LABEL_H -#define _LINUX_JUMP_LABEL_H - -/* - * Jump label support - * - * Copyright (C) 2009-2012 Jason Baron <jbaron@redhat.com> - * Copyright (C) 2011-2012 Peter Zijlstra <pzijlstr@redhat.com> - * - * Jump labels provide an interface to generate dynamic branches using - * self-modifying code. Assuming toolchain and architecture support the result - * of a "if (static_key_false(&key))" statement is a unconditional branch (which - * defaults to false - and the true block is placed out of line). - * - * However at runtime we can change the branch target using - * static_key_slow_{inc,dec}(). These function as a 'reference' count on the key - * object and for as long as there are references all branches referring to - * that particular key will point to the (out of line) true block. - * - * Since this relies on modifying code the static_key_slow_{inc,dec}() functions - * must be considered absolute slow paths (machine wide synchronization etc.). - * OTOH, since the affected branches are unconditional their runtime overhead - * will be absolutely minimal, esp. in the default (off) case where the total - * effect is a single NOP of appropriate size. The on case will patch in a jump - * to the out-of-line block. - * - * When the control is directly exposed to userspace it is prudent to delay the - * decrement to avoid high frequency code modifications which can (and do) - * cause significant performance degradation. Struct static_key_deferred and - * static_key_slow_dec_deferred() provide for this. - * - * Lacking toolchain and or architecture support, it falls back to a simple - * conditional branch. - * - * struct static_key my_key = STATIC_KEY_INIT_TRUE; - * - * if (static_key_true(&my_key)) { - * } - * - * will result in the true case being in-line and starts the key with a single - * reference. Mixing static_key_true() and static_key_false() on the same key is not - * allowed. - * - * Not initializing the key (static data is initialized to 0s anyway) is the - * same as using STATIC_KEY_INIT_FALSE and static_key_false() is - * equivalent with static_branch(). - * -*/ - -#include <linux/types.h> -#include <linux/compiler.h> -#include <linux/workqueue.h> - -#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) - -struct static_key { - atomic_t enabled; -/* Set lsb bit to 1 if branch is default true, 0 ot */ - struct jump_entry *entries; -#ifdef CONFIG_MODULES - struct static_key_mod *next; -#endif -}; - -struct static_key_deferred { - struct static_key key; - unsigned long timeout; - struct delayed_work work; -}; - -# include <asm/jump_label.h> -# define HAVE_JUMP_LABEL -#endif /* CC_HAVE_ASM_GOTO && CONFIG_JUMP_LABEL */ - -enum jump_label_type { - JUMP_LABEL_DISABLE = 0, - JUMP_LABEL_ENABLE, -}; - -struct module; - -#ifdef HAVE_JUMP_LABEL - -#define JUMP_LABEL_TRUE_BRANCH 1UL - -static -inline struct jump_entry *jump_label_get_entries(struct static_key *key) -{ - return (struct jump_entry *)((unsigned long)key->entries - & ~JUMP_LABEL_TRUE_BRANCH); -} - -static inline bool jump_label_get_branch_default(struct static_key *key) -{ - if ((unsigned long)key->entries & JUMP_LABEL_TRUE_BRANCH) - return true; - return false; -} - -static __always_inline bool static_key_false(struct static_key *key) -{ - return arch_static_branch(key); -} - -static __always_inline bool static_key_true(struct static_key *key) -{ - return !static_key_false(key); -} - -/* Deprecated. Please use 'static_key_false() instead. */ -static __always_inline bool static_branch(struct static_key *key) -{ - return arch_static_branch(key); -} - -extern struct jump_entry __start___jump_table[]; -extern struct jump_entry __stop___jump_table[]; - -extern void jump_label_init(void); -extern void jump_label_lock(void); -extern void jump_label_unlock(void); -extern void arch_jump_label_transform(struct jump_entry *entry, - enum jump_label_type type); -extern void arch_jump_label_transform_static(struct jump_entry *entry, - enum jump_label_type type); -extern int jump_label_text_reserved(void *start, void *end); -extern void static_key_slow_inc(struct static_key *key); -extern void static_key_slow_dec(struct static_key *key); -extern void static_key_slow_dec_deferred(struct static_key_deferred *key); -extern void jump_label_apply_nops(struct module *mod); -extern void -jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl); - -#define STATIC_KEY_INIT_TRUE ((struct static_key) \ - { .enabled = ATOMIC_INIT(1), .entries = (void *)1 }) -#define STATIC_KEY_INIT_FALSE ((struct static_key) \ - { .enabled = ATOMIC_INIT(0), .entries = (void *)0 }) - -#else /* !HAVE_JUMP_LABEL */ - -#include <linux/atomic.h> - -struct static_key { - atomic_t enabled; -}; - -static __always_inline void jump_label_init(void) -{ -} - -struct static_key_deferred { - struct static_key key; -}; - -static __always_inline bool static_key_false(struct static_key *key) -{ - if (unlikely(atomic_read(&key->enabled)) > 0) - return true; - return false; -} - -static __always_inline bool static_key_true(struct static_key *key) -{ - if (likely(atomic_read(&key->enabled)) > 0) - return true; - return false; -} - -/* Deprecated. Please use 'static_key_false() instead. */ -static __always_inline bool static_branch(struct static_key *key) -{ - if (unlikely(atomic_read(&key->enabled)) > 0) - return true; - return false; -} - -static inline void static_key_slow_inc(struct static_key *key) -{ - atomic_inc(&key->enabled); -} - -static inline void static_key_slow_dec(struct static_key *key) -{ - atomic_dec(&key->enabled); -} - -static inline void static_key_slow_dec_deferred(struct static_key_deferred *key) -{ - static_key_slow_dec(&key->key); -} - -static inline int jump_label_text_reserved(void *start, void *end) -{ - return 0; -} - -static inline void jump_label_lock(void) {} -static inline void jump_label_unlock(void) {} - -static inline int jump_label_apply_nops(struct module *mod) -{ - return 0; -} - -static inline void -jump_label_rate_limit(struct static_key_deferred *key, - unsigned long rl) -{ -} - -#define STATIC_KEY_INIT_TRUE ((struct static_key) \ - { .enabled = ATOMIC_INIT(1) }) -#define STATIC_KEY_INIT_FALSE ((struct static_key) \ - { .enabled = ATOMIC_INIT(0) }) - -#endif /* HAVE_JUMP_LABEL */ - -#define STATIC_KEY_INIT STATIC_KEY_INIT_FALSE -#define jump_label_enabled static_key_enabled - -static inline bool static_key_enabled(struct static_key *key) -{ - return (atomic_read(&key->enabled) > 0); -} - -#endif /* _LINUX_JUMP_LABEL_H */ |