1 #ifndef __LINUX_SPINLOCK_H 2 #define __LINUX_SPINLOCK_H 3 4 /* 5 * include/linux/spinlock.h - generic spinlock/rwlock declarations 6 * 7 * here's the role of the various spinlock/rwlock related include files: 8 * 9 * on SMP builds: 10 * 11 * asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the 12 * initializers 13 * 14 * linux/spinlock_types.h: 15 * defines the generic type and initializers 16 * 17 * asm/spinlock.h: contains the __raw_spin_*()/etc. lowlevel 18 * implementations, mostly inline assembly code 19 * 20 * (also included on UP-debug builds:) 21 * 22 * linux/spinlock_api_smp.h: 23 * contains the prototypes for the _spin_*() APIs. 24 * 25 * linux/spinlock.h: builds the final spin_*() APIs. 26 * 27 * on UP builds: 28 * 29 * linux/spinlock_type_up.h: 30 * contains the generic, simplified UP spinlock type. 31 * (which is an empty structure on non-debug builds) 32 * 33 * linux/spinlock_types.h: 34 * defines the generic type and initializers 35 * 36 * linux/spinlock_up.h: 37 * contains the __raw_spin_*()/etc. version of UP 38 * builds. (which are NOPs on non-debug, non-preempt 39 * builds) 40 * 41 * (included on UP-non-debug builds:) 42 * 43 * linux/spinlock_api_up.h: 44 * builds the _spin_*() APIs. 45 * 46 * linux/spinlock.h: builds the final spin_*() APIs. 47 */ 48 49 #include <linux/config.h> 50 #include <linux/preempt.h> 51 #include <linux/linkage.h> 52 #include <linux/compiler.h> 53 #include <linux/thread_info.h> 54 #include <linux/kernel.h> 55 #include <linux/stringify.h> 56 57 #include <asm/system.h> 58 59 /* 60 * Must define these before including other files, inline functions need them 61 */ 62 #define LOCK_SECTION_NAME \ 63 ".text.lock." __stringify(KBUILD_BASENAME) 64 65 #define LOCK_SECTION_START(extra) \ 66 ".subsection 1\n\t" \ 67 extra \ 68 ".ifndef " LOCK_SECTION_NAME "\n\t" \ 69 LOCK_SECTION_NAME ":\n\t" \ 70 ".endif\n" 71 72 #define LOCK_SECTION_END \ 73 ".previous\n\t" 74 75 #define __lockfunc fastcall __attribute__((section(".spinlock.text"))) 76 77 /* 78 * Pull the raw_spinlock_t and raw_rwlock_t definitions: 79 */ 80 #include <linux/spinlock_types.h> 81 82 extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock); 83 84 /* 85 * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them): 86 */ 87 #if defined(CONFIG_SMP) 88 # include <asm/spinlock.h> 89 #else 90 # include <linux/spinlock_up.h> 91 #endif 92 93 #define spin_lock_init(lock) do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0) 94 #define rwlock_init(lock) do { *(lock) = RW_LOCK_UNLOCKED; } while (0) 95 96 #define spin_is_locked(lock) __raw_spin_is_locked(&(lock)->raw_lock) 97 98 /** 99 * spin_unlock_wait - wait until the spinlock gets unlocked 100 * @lock: the spinlock in question. 101 */ 102 #define spin_unlock_wait(lock) __raw_spin_unlock_wait(&(lock)->raw_lock) 103 104 /* 105 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations: 106 */ 107 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 108 # include <linux/spinlock_api_smp.h> 109 #else 110 # include <linux/spinlock_api_up.h> 111 #endif 112 113 #ifdef CONFIG_DEBUG_SPINLOCK 114 extern void _raw_spin_lock(spinlock_t *lock); 115 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock) 116 extern int _raw_spin_trylock(spinlock_t *lock); 117 extern void _raw_spin_unlock(spinlock_t *lock); 118 119 extern void _raw_read_lock(rwlock_t *lock); 120 extern int _raw_read_trylock(rwlock_t *lock); 121 extern void _raw_read_unlock(rwlock_t *lock); 122 extern void _raw_write_lock(rwlock_t *lock); 123 extern int _raw_write_trylock(rwlock_t *lock); 124 extern void _raw_write_unlock(rwlock_t *lock); 125 #else 126 # define _raw_spin_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock) 127 # define _raw_spin_trylock(lock) __raw_spin_trylock(&(lock)->raw_lock) 128 # define _raw_spin_lock(lock) __raw_spin_lock(&(lock)->raw_lock) 129 # define _raw_spin_lock_flags(lock, flags) \ 130 __raw_spin_lock_flags(&(lock)->raw_lock, *(flags)) 131 # define _raw_read_lock(rwlock) __raw_read_lock(&(rwlock)->raw_lock) 132 # define _raw_write_lock(rwlock) __raw_write_lock(&(rwlock)->raw_lock) 133 # define _raw_read_unlock(rwlock) __raw_read_unlock(&(rwlock)->raw_lock) 134 # define _raw_write_unlock(rwlock) __raw_write_unlock(&(rwlock)->raw_lock) 135 # define _raw_read_trylock(rwlock) __raw_read_trylock(&(rwlock)->raw_lock) 136 # define _raw_write_trylock(rwlock) __raw_write_trylock(&(rwlock)->raw_lock) 137 #endif 138 139 #define read_can_lock(rwlock) __raw_read_can_lock(&(rwlock)->raw_lock) 140 #define write_can_lock(rwlock) __raw_write_can_lock(&(rwlock)->raw_lock) 141 142 /* 143 * Define the various spin_lock and rw_lock methods. Note we define these 144 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various 145 * methods are defined as nops in the case they are not required. 146 */ 147 #define spin_trylock(lock) __cond_lock(_spin_trylock(lock)) 148 #define read_trylock(lock) __cond_lock(_read_trylock(lock)) 149 #define write_trylock(lock) __cond_lock(_write_trylock(lock)) 150 151 #define spin_lock(lock) _spin_lock(lock) 152 #define write_lock(lock) _write_lock(lock) 153 #define read_lock(lock) _read_lock(lock) 154 155 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 156 #define spin_lock_irqsave(lock, flags) flags = _spin_lock_irqsave(lock) 157 #define read_lock_irqsave(lock, flags) flags = _read_lock_irqsave(lock) 158 #define write_lock_irqsave(lock, flags) flags = _write_lock_irqsave(lock) 159 #else 160 #define spin_lock_irqsave(lock, flags) _spin_lock_irqsave(lock, flags) 161 #define read_lock_irqsave(lock, flags) _read_lock_irqsave(lock, flags) 162 #define write_lock_irqsave(lock, flags) _write_lock_irqsave(lock, flags) 163 #endif 164 165 #define spin_lock_irq(lock) _spin_lock_irq(lock) 166 #define spin_lock_bh(lock) _spin_lock_bh(lock) 167 168 #define read_lock_irq(lock) _read_lock_irq(lock) 169 #define read_lock_bh(lock) _read_lock_bh(lock) 170 171 #define write_lock_irq(lock) _write_lock_irq(lock) 172 #define write_lock_bh(lock) _write_lock_bh(lock) 173 174 #define spin_unlock(lock) _spin_unlock(lock) 175 #define write_unlock(lock) _write_unlock(lock) 176 #define read_unlock(lock) _read_unlock(lock) 177 178 #define spin_unlock_irqrestore(lock, flags) \ 179 _spin_unlock_irqrestore(lock, flags) 180 #define spin_unlock_irq(lock) _spin_unlock_irq(lock) 181 #define spin_unlock_bh(lock) _spin_unlock_bh(lock) 182 183 #define read_unlock_irqrestore(lock, flags) \ 184 _read_unlock_irqrestore(lock, flags) 185 #define read_unlock_irq(lock) _read_unlock_irq(lock) 186 #define read_unlock_bh(lock) _read_unlock_bh(lock) 187 188 #define write_unlock_irqrestore(lock, flags) \ 189 _write_unlock_irqrestore(lock, flags) 190 #define write_unlock_irq(lock) _write_unlock_irq(lock) 191 #define write_unlock_bh(lock) _write_unlock_bh(lock) 192 193 #define spin_trylock_bh(lock) __cond_lock(_spin_trylock_bh(lock)) 194 195 #define spin_trylock_irq(lock) \ 196 ({ \ 197 local_irq_disable(); \ 198 _spin_trylock(lock) ? \ 199 1 : ({ local_irq_enable(); 0; }); \ 200 }) 201 202 #define spin_trylock_irqsave(lock, flags) \ 203 ({ \ 204 local_irq_save(flags); \ 205 _spin_trylock(lock) ? \ 206 1 : ({ local_irq_restore(flags); 0; }); \ 207 }) 208 209 /* 210 * Pull the atomic_t declaration: 211 * (asm-mips/atomic.h needs above definitions) 212 */ 213 #include <asm/atomic.h> 214 /** 215 * atomic_dec_and_lock - lock on reaching reference count zero 216 * @atomic: the atomic counter 217 * @lock: the spinlock in question 218 */ 219 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); 220 #define atomic_dec_and_lock(atomic, lock) \ 221 __cond_lock(_atomic_dec_and_lock(atomic, lock)) 222 223 /** 224 * spin_can_lock - would spin_trylock() succeed? 225 * @lock: the spinlock in question. 226 */ 227 #define spin_can_lock(lock) (!spin_is_locked(lock)) 228 229 #endif /* __LINUX_SPINLOCK_H */ 230