include/asm-parisc/spinlock.h

   1 #ifndef __ASM_SPINLOCK_H
   2 #define __ASM_SPINLOCK_H
   3
   4 #include <asm/system.h>
   5
   6 /* Note that PA-RISC has to use `1' to mean unlocked and `0' to mean locked
   7  * since it only has load-and-zero. Moreover, at least on some PA processors,
   8  * the semaphore address has to be 16-byte aligned.
   9  */
  10
  11 #ifndef CONFIG_DEBUG_SPINLOCK
  12
  13 #define __SPIN_LOCK_UNLOCKED    { { 1, 1, 1, 1 } }
  14 #undef SPIN_LOCK_UNLOCKED
  15 #define SPIN_LOCK_UNLOCKED (spinlock_t) __SPIN_LOCK_UNLOCKED
  16
  17 #define spin_lock_init(x)       do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
  18
  19 static inline int spin_is_locked(spinlock_t *x)
  20 {
  21         volatile unsigned int *a = __ldcw_align(x);
  22         return *a == 0;
  23 }
  24
  25 #define spin_unlock_wait(x)     do { barrier(); } while(spin_is_locked(x))
  26 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
  27
  28 static inline void _raw_spin_lock(spinlock_t *x)
  29 {
  30         volatile unsigned int *a;
  31
  32         mb();
  33         a = __ldcw_align(x);
  34         while (__ldcw(a) == 0)
  35                 while (*a == 0);
  36         mb();
  37 }
  38
  39 static inline void _raw_spin_unlock(spinlock_t *x)
  40 {
  41         volatile unsigned int *a;
  42         mb();
  43         a = __ldcw_align(x);
  44         *a = 1;
  45         mb();
  46 }
  47
  48 static inline int _raw_spin_trylock(spinlock_t *x)
  49 {
  50         volatile unsigned int *a;
  51         int ret;
  52
  53         mb();
  54         a = __ldcw_align(x);
  55         ret = __ldcw(a) != 0;
  56         mb();
  57
  58         return ret;
  59 }
  60
  61 #define spin_lock_own(LOCK, LOCATION)   ((void)0)
  62
  63 #else /* !(CONFIG_DEBUG_SPINLOCK) */
  64
  65 #define SPINLOCK_MAGIC  0x1D244B3C
  66
  67 #define __SPIN_LOCK_UNLOCKED    { { 1, 1, 1, 1 }, SPINLOCK_MAGIC, 10, __FILE__ , NULL, 0, -1, NULL, NULL }
  68 #undef SPIN_LOCK_UNLOCKED
  69 #define SPIN_LOCK_UNLOCKED (spinlock_t) __SPIN_LOCK_UNLOCKED
  70
  71 #define spin_lock_init(x)       do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
  72
  73 #define CHECK_LOCK(x)                                                   \
  74         do {                                                            \
  75                 if (unlikely((x)->magic != SPINLOCK_MAGIC)) {                   \
  76                         printk(KERN_ERR "%s:%d: spin_is_locked"         \
  77                         " on uninitialized spinlock %p.\n",             \
  78                                 __FILE__, __LINE__, (x));               \
  79                 }                                                       \
  80         } while(0)
  81
  82 #define spin_is_locked(x)                                               \
  83         ({                                                              \
  84                 CHECK_LOCK(x);                                          \
  85                 volatile unsigned int *a = __ldcw_align(x);             \
  86                 if (unlikely((*a == 0) && (x)->babble)) {                               \
  87                         (x)->babble--;                                  \
  88                         printk("KERN_WARNING                            \
  89                                 %s:%d: spin_is_locked(%s/%p) already"   \
  90                                 " locked by %s:%d in %s at %p(%d)\n",   \
  91                                 __FILE__,__LINE__, (x)->module, (x),    \
  92                                 (x)->bfile, (x)->bline, (x)->task->comm,\
  93                                 (x)->previous, (x)->oncpu);             \
  94                 }                                                       \
  95                 *a == 0;                                                \
  96         })
  97
  98 #define spin_unlock_wait(x)                                             \
  99         do {                                                            \
 100                 CHECK_LOCK(x);                                          \
 101                 volatile unsigned int *a = __ldcw_align(x);             \
 102                 if (unlikely((*a == 0) && (x)->babble)) {                               \
 103                         (x)->babble--;                                  \
 104                         printk("KERN_WARNING                            \
 105                                 %s:%d: spin_unlock_wait(%s/%p)"         \
 106                                 " owned by %s:%d in %s at %p(%d)\n",    \
 107                                 __FILE__,__LINE__, (x)->module, (x),    \
 108                                 (x)->bfile, (x)->bline, (x)->task->comm,\
 109                                 (x)->previous, (x)->oncpu);             \
 110                 }                                                       \
 111                 barrier();                                              \
 112         } while (*((volatile unsigned char *)(__ldcw_align(x))) == 0)
 113
 114 extern void _dbg_spin_lock(spinlock_t *lock, const char *base_file, int line_no);
 115 extern void _dbg_spin_unlock(spinlock_t *lock, const char *, int);
 116 extern int _dbg_spin_trylock(spinlock_t * lock, const char *, int);
 117
 118 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
 119
 120 #define _raw_spin_unlock(lock)  _dbg_spin_unlock(lock, __FILE__, __LINE__)
 121 #define _raw_spin_lock(lock) _dbg_spin_lock(lock, __FILE__, __LINE__)
 122 #define _raw_spin_trylock(lock) _dbg_spin_trylock(lock, __FILE__, __LINE__)
 123
 124 /* just in case we need it */
 125 #define spin_lock_own(LOCK, LOCATION)                                   \
 126 do {                                                                    \
 127         volatile unsigned int *a = __ldcw_align(LOCK);                  \
 128         if (!((*a == 0) && ((LOCK)->oncpu == smp_processor_id())))      \
 129                 printk("KERN_WARNING                                    \
 130                         %s: called on %d from %p but lock %s on %d\n",  \
 131                         LOCATION, smp_processor_id(),                   \
 132                         __builtin_return_address(0),                    \
 133                         (*a == 0) ? "taken" : "freed", (LOCK)->on_cpu); \
 134 } while (0)
 135
 136 #endif /* !(CONFIG_DEBUG_SPINLOCK) */
 137
 138 /*
 139  * Read-write spinlocks, allowing multiple readers
 140  * but only one writer.
 141  */
 142 typedef struct {
 143         spinlock_t lock;
 144         volatile int counter;
 145 #ifdef CONFIG_PREEMPT
 146         unsigned int break_lock;
 147 #endif
 148 } rwlock_t;
 149
 150 #define RW_LOCK_UNLOCKED (rwlock_t) { __SPIN_LOCK_UNLOCKED, 0 }
 151
 152 #define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while (0)
 153
 154 #define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
 155
 156 /* read_lock, read_unlock are pretty straightforward.  Of course it somehow
 157  * sucks we end up saving/restoring flags twice for read_lock_irqsave aso. */
 158
 159 #ifdef CONFIG_DEBUG_RWLOCK
 160 extern void _dbg_read_lock(rwlock_t * rw, const char *bfile, int bline);
 161 #define _raw_read_lock(rw) _dbg_read_lock(rw, __FILE__, __LINE__)
 162 #else
 163 static  __inline__ void _raw_read_lock(rwlock_t *rw)
 164 {
 165         unsigned long flags;
 166         local_irq_save(flags);
 167         _raw_spin_lock(&rw->lock);
 168
 169         rw->counter++;
 170
 171         _raw_spin_unlock(&rw->lock);
 172         local_irq_restore(flags);
 173 }
 174 #endif  /* CONFIG_DEBUG_RWLOCK */
 175
 176 static  __inline__ void _raw_read_unlock(rwlock_t *rw)
 177 {
 178         unsigned long flags;
 179         local_irq_save(flags);
 180         _raw_spin_lock(&rw->lock);
 181
 182         rw->counter--;
 183
 184         _raw_spin_unlock(&rw->lock);
 185         local_irq_restore(flags);
 186 }
 187
 188 /* write_lock is less trivial.  We optimistically grab the lock and check
 189  * if we surprised any readers.  If so we release the lock and wait till
 190  * they're all gone before trying again
 191  *
 192  * Also note that we don't use the _irqsave / _irqrestore suffixes here.
 193  * If we're called with interrupts enabled and we've got readers (or other
 194  * writers) in interrupt handlers someone fucked up and we'd dead-lock
 195  * sooner or later anyway.   prumpf */
 196
 197 #ifdef CONFIG_DEBUG_RWLOCK
 198 extern void _dbg_write_lock(rwlock_t * rw, const char *bfile, int bline);
 199 #define _raw_write_lock(rw) _dbg_write_lock(rw, __FILE__, __LINE__)
 200 #else
 201 static  __inline__ void _raw_write_lock(rwlock_t *rw)
 202 {
 203 retry:
 204         _raw_spin_lock(&rw->lock);
 205
 206         if(rw->counter != 0) {
 207                 /* this basically never happens */
 208                 _raw_spin_unlock(&rw->lock);
 209
 210                 while(rw->counter != 0);
 211
 212                 goto retry;
 213         }
 214
 215         /* got it.  now leave without unlocking */
 216         rw->counter = -1; /* remember we are locked */
 217 }
 218 #endif /* CONFIG_DEBUG_RWLOCK */
 219
 220 /* write_unlock is absolutely trivial - we don't have to wait for anything */
 221
 222 static  __inline__ void _raw_write_unlock(rwlock_t *rw)
 223 {
 224         rw->counter = 0;
 225         _raw_spin_unlock(&rw->lock);
 226 }
 227
 228 #ifdef CONFIG_DEBUG_RWLOCK
 229 extern int _dbg_write_trylock(rwlock_t * rw, const char *bfile, int bline);
 230 #define _raw_write_trylock(rw) _dbg_write_trylock(rw, __FILE__, __LINE__)
 231 #else
 232 static  __inline__ int _raw_write_trylock(rwlock_t *rw)
 233 {
 234         _raw_spin_lock(&rw->lock);
 235         if (rw->counter != 0) {
 236                 /* this basically never happens */
 237                 _raw_spin_unlock(&rw->lock);
 238
 239                 return 0;
 240         }
 241
 242         /* got it.  now leave without unlocking */
 243         rw->counter = -1; /* remember we are locked */
 244         return 1;
 245 }
 246 #endif /* CONFIG_DEBUG_RWLOCK */
 247
 248 static __inline__ int is_read_locked(rwlock_t *rw)
 249 {
 250         return rw->counter > 0;
 251 }
 252
 253 static __inline__ int is_write_locked(rwlock_t *rw)
 254 {
 255         return rw->counter < 0;
 256 }
 257
 258 #endif /* __ASM_SPINLOCK_H */