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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 422 | giacomo | 1 | #ifndef __LINUX_SPINLOCK_H |
| 2 | #define __LINUX_SPINLOCK_H |
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| 3 | |||
| 4 | /* |
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| 5 | * include/linux/spinlock.h - generic locking declarations |
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| 6 | */ |
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| 7 | |||
| 8 | #include <linux/config.h> |
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| 9 | #include <linux/preempt.h> |
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| 10 | #include <linux/linkage.h> |
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| 11 | #include <linux/compiler.h> |
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| 12 | #include <linux/thread_info.h> |
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| 13 | #include <linux/kernel.h> |
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| 14 | #include <linux/stringify.h> |
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| 15 | |||
| 16 | #include <asm/processor.h> /* for cpu relax */ |
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| 17 | #include <asm/system.h> |
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| 18 | |||
| 19 | /* |
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| 20 | * Must define these before including other files, inline functions need them |
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| 21 | */ |
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| 22 | #define LOCK_SECTION_NAME \ |
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| 23 | ".text.lock." __stringify(KBUILD_BASENAME) |
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| 24 | |||
| 25 | #define LOCK_SECTION_START(extra) \ |
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| 26 | ".subsection 1\n\t" \ |
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| 27 | extra \ |
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| 28 | ".ifndef " LOCK_SECTION_NAME "\n\t" \ |
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| 29 | LOCK_SECTION_NAME ":\n\t" \ |
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| 30 | ".endif\n\t" |
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| 31 | |||
| 32 | #define LOCK_SECTION_END \ |
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| 33 | ".previous\n\t" |
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| 34 | |||
| 35 | /* |
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| 36 | * If CONFIG_SMP is set, pull in the _raw_* definitions |
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| 37 | */ |
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| 38 | #ifdef CONFIG_SMP |
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| 39 | #include <asm/spinlock.h> |
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| 40 | |||
| 41 | #else |
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| 42 | |||
| 43 | #if !defined(CONFIG_PREEMPT) && !defined(CONFIG_DEBUG_SPINLOCK) |
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| 44 | # define atomic_dec_and_lock(atomic,lock) atomic_dec_and_test(atomic) |
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| 45 | # define ATOMIC_DEC_AND_LOCK |
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| 46 | #endif |
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| 47 | |||
| 48 | #ifdef CONFIG_DEBUG_SPINLOCK |
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| 49 | |||
| 50 | #define SPINLOCK_MAGIC 0x1D244B3C |
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| 51 | typedef struct { |
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| 52 | unsigned long magic; |
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| 53 | volatile unsigned long lock; |
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| 54 | volatile unsigned int babble; |
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| 55 | const char *module; |
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| 56 | char *owner; |
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| 57 | int oline; |
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| 58 | } spinlock_t; |
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| 59 | #define SPIN_LOCK_UNLOCKED (spinlock_t) { SPINLOCK_MAGIC, 0, 10, __FILE__ , NULL, 0} |
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| 60 | |||
| 61 | #define spin_lock_init(x) \ |
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| 62 | do { \ |
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| 63 | (x)->magic = SPINLOCK_MAGIC; \ |
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| 64 | (x)->lock = 0; \ |
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| 65 | (x)->babble = 5; \ |
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| 66 | (x)->module = __FILE__; \ |
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| 67 | (x)->owner = NULL; \ |
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| 68 | (x)->oline = 0; \ |
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| 69 | } while (0) |
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| 70 | |||
| 71 | #define CHECK_LOCK(x) \ |
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| 72 | do { \ |
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| 73 | if ((x)->magic != SPINLOCK_MAGIC) { \ |
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| 74 | printk(KERN_ERR "%s:%d: spin_is_locked on uninitialized spinlock %p.\n", \ |
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| 75 | __FILE__, __LINE__, (x)); \ |
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| 76 | } \ |
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| 77 | } while(0) |
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| 78 | |||
| 79 | #define _raw_spin_lock(x) \ |
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| 80 | do { \ |
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| 81 | CHECK_LOCK(x); \ |
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| 82 | if ((x)->lock&&(x)->babble) { \ |
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| 83 | (x)->babble--; \ |
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| 84 | printk("%s:%d: spin_lock(%s:%p) already locked by %s/%d\n", \ |
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| 85 | __FILE__,__LINE__, (x)->module, \ |
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| 86 | (x), (x)->owner, (x)->oline); \ |
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| 87 | } \ |
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| 88 | (x)->lock = 1; \ |
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| 89 | (x)->owner = __FILE__; \ |
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| 90 | (x)->oline = __LINE__; \ |
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| 91 | } while (0) |
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| 92 | |||
| 93 | /* without debugging, spin_is_locked on UP always says |
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| 94 | * FALSE. --> printk if already locked. */ |
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| 95 | #define spin_is_locked(x) \ |
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| 96 | ({ \ |
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| 97 | CHECK_LOCK(x); \ |
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| 98 | if ((x)->lock&&(x)->babble) { \ |
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| 99 | (x)->babble--; \ |
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| 100 | printk("%s:%d: spin_is_locked(%s:%p) already locked by %s/%d\n", \ |
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| 101 | __FILE__,__LINE__, (x)->module, \ |
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| 102 | (x), (x)->owner, (x)->oline); \ |
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| 103 | } \ |
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| 104 | 0; \ |
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| 105 | }) |
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| 106 | |||
| 107 | /* without debugging, spin_trylock on UP always says |
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| 108 | * TRUE. --> printk if already locked. */ |
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| 109 | #define _raw_spin_trylock(x) \ |
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| 110 | ({ \ |
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| 111 | CHECK_LOCK(x); \ |
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| 112 | if ((x)->lock&&(x)->babble) { \ |
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| 113 | (x)->babble--; \ |
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| 114 | printk("%s:%d: spin_trylock(%s:%p) already locked by %s/%d\n", \ |
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| 115 | __FILE__,__LINE__, (x)->module, \ |
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| 116 | (x), (x)->owner, (x)->oline); \ |
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| 117 | } \ |
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| 118 | (x)->lock = 1; \ |
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| 119 | (x)->owner = __FILE__; \ |
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| 120 | (x)->oline = __LINE__; \ |
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| 121 | 1; \ |
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| 122 | }) |
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| 123 | |||
| 124 | #define spin_unlock_wait(x) \ |
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| 125 | do { \ |
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| 126 | CHECK_LOCK(x); \ |
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| 127 | if ((x)->lock&&(x)->babble) { \ |
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| 128 | (x)->babble--; \ |
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| 129 | printk("%s:%d: spin_unlock_wait(%s:%p) owned by %s/%d\n", \ |
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| 130 | __FILE__,__LINE__, (x)->module, (x), \ |
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| 131 | (x)->owner, (x)->oline); \ |
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| 132 | }\ |
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| 133 | } while (0) |
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| 134 | |||
| 135 | #define _raw_spin_unlock(x) \ |
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| 136 | do { \ |
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| 137 | CHECK_LOCK(x); \ |
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| 138 | if (!(x)->lock&&(x)->babble) { \ |
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| 139 | (x)->babble--; \ |
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| 140 | printk("%s:%d: spin_unlock(%s:%p) not locked\n", \ |
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| 141 | __FILE__,__LINE__, (x)->module, (x));\ |
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| 142 | } \ |
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| 143 | (x)->lock = 0; \ |
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| 144 | } while (0) |
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| 145 | #else |
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| 146 | /* |
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| 147 | * gcc versions before ~2.95 have a nasty bug with empty initializers. |
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| 148 | */ |
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| 149 | #if (__GNUC__ > 2) |
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| 150 | typedef struct { } spinlock_t; |
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| 151 | #define SPIN_LOCK_UNLOCKED (spinlock_t) { } |
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| 152 | #else |
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| 153 | typedef struct { int gcc_is_buggy; } spinlock_t; |
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| 154 | #define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 } |
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| 155 | #endif |
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| 156 | |||
| 157 | /* |
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| 158 | * If CONFIG_SMP is unset, declare the _raw_* definitions as nops |
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| 159 | */ |
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| 160 | #define spin_lock_init(lock) do { (void)(lock); } while(0) |
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| 161 | #define _raw_spin_lock(lock) do { (void)(lock); } while(0) |
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| 162 | #define spin_is_locked(lock) ((void)(lock), 0) |
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| 163 | #define _raw_spin_trylock(lock) ((void)(lock), 1) |
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| 164 | #define spin_unlock_wait(lock) do { (void)(lock); } while(0) |
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| 165 | #define _raw_spin_unlock(lock) do { (void)(lock); } while(0) |
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| 166 | #endif /* CONFIG_DEBUG_SPINLOCK */ |
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| 167 | |||
| 168 | /* RW spinlocks: No debug version */ |
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| 169 | |||
| 170 | #if (__GNUC__ > 2) |
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| 171 | typedef struct { } rwlock_t; |
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| 172 | #define RW_LOCK_UNLOCKED (rwlock_t) { } |
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| 173 | #else |
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| 174 | typedef struct { int gcc_is_buggy; } rwlock_t; |
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| 175 | #define RW_LOCK_UNLOCKED (rwlock_t) { 0 } |
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| 176 | #endif |
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| 177 | |||
| 178 | #define rwlock_init(lock) do { (void)(lock); } while(0) |
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| 179 | #define _raw_read_lock(lock) do { (void)(lock); } while(0) |
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| 180 | #define _raw_read_unlock(lock) do { (void)(lock); } while(0) |
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| 181 | #define _raw_write_lock(lock) do { (void)(lock); } while(0) |
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| 182 | #define _raw_write_unlock(lock) do { (void)(lock); } while(0) |
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| 183 | #define _raw_write_trylock(lock) ({ (void)(lock); (1); }) |
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| 184 | |||
| 185 | #endif /* !SMP */ |
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| 186 | |||
| 187 | /* |
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| 188 | * Define the various spin_lock and rw_lock methods. Note we define these |
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| 189 | * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various |
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| 190 | * methods are defined as nops in the case they are not required. |
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| 191 | */ |
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| 192 | #define spin_trylock(lock) ({preempt_disable(); _raw_spin_trylock(lock) ? \ |
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| 193 | 1 : ({preempt_enable(); 0;});}) |
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| 194 | |||
| 195 | #define write_trylock(lock) ({preempt_disable();_raw_write_trylock(lock) ? \ |
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| 196 | 1 : ({preempt_enable(); 0;});}) |
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| 197 | |||
| 198 | /* Where's read_trylock? */ |
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| 199 | |||
| 200 | #if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT) |
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| 201 | void __preempt_spin_lock(spinlock_t *lock); |
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| 202 | void __preempt_write_lock(rwlock_t *lock); |
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| 203 | |||
| 204 | #define spin_lock(lock) \ |
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| 205 | do { \ |
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| 206 | preempt_disable(); \ |
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| 207 | if (unlikely(!_raw_spin_trylock(lock))) \ |
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| 208 | __preempt_spin_lock(lock); \ |
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| 209 | } while (0) |
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| 210 | |||
| 211 | #define write_lock(lock) \ |
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| 212 | do { \ |
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| 213 | preempt_disable(); \ |
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| 214 | if (unlikely(!_raw_write_trylock(lock))) \ |
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| 215 | __preempt_write_lock(lock); \ |
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| 216 | } while (0) |
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| 217 | |||
| 218 | #else |
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| 219 | #define spin_lock(lock) \ |
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| 220 | do { \ |
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| 221 | preempt_disable(); \ |
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| 222 | _raw_spin_lock(lock); \ |
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| 223 | } while(0) |
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| 224 | |||
| 225 | #define write_lock(lock) \ |
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| 226 | do { \ |
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| 227 | preempt_disable(); \ |
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| 228 | _raw_write_lock(lock); \ |
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| 229 | } while(0) |
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| 230 | #endif |
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| 231 | |||
| 232 | #define read_lock(lock) \ |
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| 233 | do { \ |
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| 234 | preempt_disable(); \ |
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| 235 | _raw_read_lock(lock); \ |
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| 236 | } while(0) |
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| 237 | |||
| 238 | #define spin_unlock(lock) \ |
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| 239 | do { \ |
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| 240 | _raw_spin_unlock(lock); \ |
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| 241 | preempt_enable(); \ |
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| 242 | } while (0) |
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| 243 | |||
| 244 | #define write_unlock(lock) \ |
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| 245 | do { \ |
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| 246 | _raw_write_unlock(lock); \ |
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| 247 | preempt_enable(); \ |
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| 248 | } while(0) |
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| 249 | |||
| 250 | #define read_unlock(lock) \ |
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| 251 | do { \ |
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| 252 | _raw_read_unlock(lock); \ |
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| 253 | preempt_enable(); \ |
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| 254 | } while(0) |
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| 255 | |||
| 256 | #define spin_lock_irqsave(lock, flags) \ |
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| 257 | do { \ |
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| 258 | local_irq_save(flags); \ |
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| 259 | preempt_disable(); \ |
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| 260 | _raw_spin_lock(lock); \ |
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| 261 | } while (0) |
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| 262 | |||
| 263 | #define spin_lock_irq(lock) \ |
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| 264 | do { \ |
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| 265 | local_irq_disable(); \ |
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| 266 | preempt_disable(); \ |
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| 267 | _raw_spin_lock(lock); \ |
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| 268 | } while (0) |
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| 269 | |||
| 270 | #define spin_lock_bh(lock) \ |
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| 271 | do { \ |
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| 272 | local_bh_disable(); \ |
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| 273 | preempt_disable(); \ |
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| 274 | _raw_spin_lock(lock); \ |
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| 275 | } while (0) |
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| 276 | |||
| 277 | #define read_lock_irqsave(lock, flags) \ |
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| 278 | do { \ |
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| 279 | local_irq_save(flags); \ |
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| 280 | preempt_disable(); \ |
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| 281 | _raw_read_lock(lock); \ |
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| 282 | } while (0) |
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| 283 | |||
| 284 | #define read_lock_irq(lock) \ |
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| 285 | do { \ |
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| 286 | local_irq_disable(); \ |
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| 287 | preempt_disable(); \ |
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| 288 | _raw_read_lock(lock); \ |
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| 289 | } while (0) |
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| 290 | |||
| 291 | #define read_lock_bh(lock) \ |
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| 292 | do { \ |
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| 293 | local_bh_disable(); \ |
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| 294 | preempt_disable(); \ |
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| 295 | _raw_read_lock(lock); \ |
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| 296 | } while (0) |
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| 297 | |||
| 298 | #define write_lock_irqsave(lock, flags) \ |
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| 299 | do { \ |
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| 300 | local_irq_save(flags); \ |
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| 301 | preempt_disable(); \ |
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| 302 | _raw_write_lock(lock); \ |
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| 303 | } while (0) |
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| 304 | |||
| 305 | #define write_lock_irq(lock) \ |
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| 306 | do { \ |
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| 307 | local_irq_disable(); \ |
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| 308 | preempt_disable(); \ |
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| 309 | _raw_write_lock(lock); \ |
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| 310 | } while (0) |
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| 311 | |||
| 312 | #define write_lock_bh(lock) \ |
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| 313 | do { \ |
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| 314 | local_bh_disable(); \ |
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| 315 | preempt_disable(); \ |
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| 316 | _raw_write_lock(lock); \ |
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| 317 | } while (0) |
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| 318 | |||
| 319 | #define spin_unlock_irqrestore(lock, flags) \ |
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| 320 | do { \ |
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| 321 | _raw_spin_unlock(lock); \ |
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| 322 | local_irq_restore(flags); \ |
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| 323 | preempt_enable(); \ |
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| 324 | } while (0) |
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| 325 | |||
| 326 | #define _raw_spin_unlock_irqrestore(lock, flags) \ |
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| 327 | do { \ |
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| 328 | _raw_spin_unlock(lock); \ |
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| 329 | local_irq_restore(flags); \ |
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| 330 | } while (0) |
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| 331 | |||
| 332 | #define spin_unlock_irq(lock) \ |
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| 333 | do { \ |
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| 334 | _raw_spin_unlock(lock); \ |
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| 335 | local_irq_enable(); \ |
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| 336 | preempt_enable(); \ |
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| 337 | } while (0) |
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| 338 | |||
| 339 | #define spin_unlock_bh(lock) \ |
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| 340 | do { \ |
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| 341 | _raw_spin_unlock(lock); \ |
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| 342 | preempt_enable(); \ |
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| 343 | local_bh_enable(); \ |
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| 344 | } while (0) |
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| 345 | |||
| 346 | #define read_unlock_irqrestore(lock, flags) \ |
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| 347 | do { \ |
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| 348 | _raw_read_unlock(lock); \ |
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| 349 | local_irq_restore(flags); \ |
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| 350 | preempt_enable(); \ |
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| 351 | } while (0) |
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| 352 | |||
| 353 | #define read_unlock_irq(lock) \ |
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| 354 | do { \ |
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| 355 | _raw_read_unlock(lock); \ |
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| 356 | local_irq_enable(); \ |
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| 357 | preempt_enable(); \ |
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| 358 | } while (0) |
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| 359 | |||
| 360 | #define read_unlock_bh(lock) \ |
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| 361 | do { \ |
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| 362 | _raw_read_unlock(lock); \ |
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| 363 | preempt_enable(); \ |
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| 364 | local_bh_enable(); \ |
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| 365 | } while (0) |
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| 366 | |||
| 367 | #define write_unlock_irqrestore(lock, flags) \ |
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| 368 | do { \ |
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| 369 | _raw_write_unlock(lock); \ |
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| 370 | local_irq_restore(flags); \ |
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| 371 | preempt_enable(); \ |
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| 372 | } while (0) |
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| 373 | |||
| 374 | #define write_unlock_irq(lock) \ |
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| 375 | do { \ |
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| 376 | _raw_write_unlock(lock); \ |
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| 377 | local_irq_enable(); \ |
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| 378 | preempt_enable(); \ |
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| 379 | } while (0) |
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| 380 | |||
| 381 | #define write_unlock_bh(lock) \ |
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| 382 | do { \ |
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| 383 | _raw_write_unlock(lock); \ |
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| 384 | preempt_enable(); \ |
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| 385 | local_bh_enable(); \ |
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| 386 | } while (0) |
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| 387 | |||
| 388 | #define spin_trylock_bh(lock) ({ local_bh_disable(); preempt_disable(); \ |
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| 389 | _raw_spin_trylock(lock) ? 1 : \ |
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| 390 | ({preempt_enable(); local_bh_enable(); 0;});}) |
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| 391 | |||
| 392 | /* "lock on reference count zero" */ |
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| 393 | #ifndef ATOMIC_DEC_AND_LOCK |
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| 394 | #include <asm/atomic.h> |
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| 395 | extern int atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); |
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| 396 | #endif |
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| 397 | |||
| 398 | /* |
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| 399 | * bit-based spin_lock() |
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| 400 | * |
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| 401 | * Don't use this unless you really need to: spin_lock() and spin_unlock() |
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| 402 | * are significantly faster. |
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| 403 | */ |
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| 404 | static inline void bit_spin_lock(int bitnum, unsigned long *addr) |
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| 405 | { |
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| 406 | /* |
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| 407 | * Assuming the lock is uncontended, this never enters |
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| 408 | * the body of the outer loop. If it is contended, then |
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| 409 | * within the inner loop a non-atomic test is used to |
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| 410 | * busywait with less bus contention for a good time to |
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| 411 | * attempt to acquire the lock bit. |
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| 412 | */ |
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| 413 | preempt_disable(); |
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| 414 | #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) |
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| 415 | while (test_and_set_bit(bitnum, addr)) { |
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| 416 | while (test_bit(bitnum, addr)) |
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| 417 | cpu_relax(); |
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| 418 | } |
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| 419 | #endif |
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| 420 | } |
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| 421 | |||
| 422 | /* |
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| 423 | * Return true if it was acquired |
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| 424 | */ |
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| 425 | static inline int bit_spin_trylock(int bitnum, unsigned long *addr) |
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| 426 | { |
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| 427 | #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) |
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| 428 | int ret; |
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| 429 | |||
| 430 | preempt_disable(); |
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| 431 | ret = !test_and_set_bit(bitnum, addr); |
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| 432 | if (!ret) |
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| 433 | preempt_enable(); |
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| 434 | return ret; |
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| 435 | #else |
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| 436 | preempt_disable(); |
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| 437 | return 1; |
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| 438 | #endif |
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| 439 | } |
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| 440 | |||
| 441 | /* |
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| 442 | * bit-based spin_unlock() |
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| 443 | */ |
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| 444 | static inline void bit_spin_unlock(int bitnum, unsigned long *addr) |
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| 445 | { |
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| 446 | #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) |
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| 447 | BUG_ON(!test_bit(bitnum, addr)); |
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| 448 | smp_mb__before_clear_bit(); |
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| 449 | clear_bit(bitnum, addr); |
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| 450 | #endif |
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| 451 | preempt_enable(); |
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| 452 | } |
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| 453 | |||
| 454 | /* |
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| 455 | * Return true if the lock is held. |
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| 456 | */ |
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| 457 | static inline int bit_spin_is_locked(int bitnum, unsigned long *addr) |
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| 458 | { |
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| 459 | #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) |
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| 460 | return test_bit(bitnum, addr); |
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| 461 | #elif defined CONFIG_PREEMPT |
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| 462 | return preempt_count(); |
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| 463 | #else |
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| 464 | return 1; |
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| 465 | #endif |
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| 466 | } |
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| 467 | |||
| 468 | #endif /* __LINUX_SPINLOCK_H */ |