arch/alpha/include/asm/spinlock.h

   1 #ifndef _ALPHA_SPINLOCK_H
   2 #define _ALPHA_SPINLOCK_H
   3
   4 #include <linux/kernel.h>
   5 #include <asm/current.h>
   6 #include <asm/barrier.h>
   7 #include <asm/processor.h>
   8
   9 /*
  10  * Simple spin lock operations.  There are two variants, one clears IRQ's
  11  * on the local processor, one does not.
  12  *
  13  * We make no fairness assumptions. They have a cost.
  14  */
  15
  16 #define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
  17 #define arch_spin_is_locked(x)  ((x)->lock != 0)
  18
  19 static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
  20 {
  21         smp_cond_load_acquire(&lock->lock, !VAL);
  22 }
  23
  24 static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
  25 {
  26         return lock.lock == 0;
  27 }
  28
  29 static inline void arch_spin_unlock(arch_spinlock_t * lock)
  30 {
  31         mb();
  32         lock->lock = 0;
  33 }
  34
  35 static inline void arch_spin_lock(arch_spinlock_t * lock)
  36 {
  37         long tmp;
  38
  39         __asm__ __volatile__(
  40         "1:     ldl_l   %0,%1\n"
  41         "       bne     %0,2f\n"
  42         "       lda     %0,1\n"
  43         "       stl_c   %0,%1\n"
  44         "       beq     %0,2f\n"
  45         "       mb\n"
  46         ".subsection 2\n"
  47         "2:     ldl     %0,%1\n"
  48         "       bne     %0,2b\n"
  49         "       br      1b\n"
  50         ".previous"
  51         : "=&r" (tmp), "=m" (lock->lock)
  52         : "m"(lock->lock) : "memory");
  53 }
  54
  55 static inline int arch_spin_trylock(arch_spinlock_t *lock)
  56 {
  57         return !test_and_set_bit(0, &lock->lock);
  58 }
  59
  60 /***********************************************************/
  61
  62 static inline int arch_read_can_lock(arch_rwlock_t *lock)
  63 {
  64         return (lock->lock & 1) == 0;
  65 }
  66
  67 static inline int arch_write_can_lock(arch_rwlock_t *lock)
  68 {
  69         return lock->lock == 0;
  70 }
  71
  72 static inline void arch_read_lock(arch_rwlock_t *lock)
  73 {
  74         long regx;
  75
  76         __asm__ __volatile__(
  77         "1:     ldl_l   %1,%0\n"
  78         "       blbs    %1,6f\n"
  79         "       subl    %1,2,%1\n"
  80         "       stl_c   %1,%0\n"
  81         "       beq     %1,6f\n"
  82         "       mb\n"
  83         ".subsection 2\n"
  84         "6:     ldl     %1,%0\n"
  85         "       blbs    %1,6b\n"
  86         "       br      1b\n"
  87         ".previous"
  88         : "=m" (*lock), "=&r" (regx)
  89         : "m" (*lock) : "memory");
  90 }
  91
  92 static inline void arch_write_lock(arch_rwlock_t *lock)
  93 {
  94         long regx;
  95
  96         __asm__ __volatile__(
  97         "1:     ldl_l   %1,%0\n"
  98         "       bne     %1,6f\n"
  99         "       lda     %1,1\n"
 100         "       stl_c   %1,%0\n"
 101         "       beq     %1,6f\n"
 102         "       mb\n"
 103         ".subsection 2\n"
 104         "6:     ldl     %1,%0\n"
 105         "       bne     %1,6b\n"
 106         "       br      1b\n"
 107         ".previous"
 108         : "=m" (*lock), "=&r" (regx)
 109         : "m" (*lock) : "memory");
 110 }
 111
 112 static inline int arch_read_trylock(arch_rwlock_t * lock)
 113 {
 114         long regx;
 115         int success;
 116
 117         __asm__ __volatile__(
 118         "1:     ldl_l   %1,%0\n"
 119         "       lda     %2,0\n"
 120         "       blbs    %1,2f\n"
 121         "       subl    %1,2,%2\n"
 122         "       stl_c   %2,%0\n"
 123         "       beq     %2,6f\n"
 124         "2:     mb\n"
 125         ".subsection 2\n"
 126         "6:     br      1b\n"
 127         ".previous"
 128         : "=m" (*lock), "=&r" (regx), "=&r" (success)
 129         : "m" (*lock) : "memory");
 130
 131         return success;
 132 }
 133
 134 static inline int arch_write_trylock(arch_rwlock_t * lock)
 135 {
 136         long regx;
 137         int success;
 138
 139         __asm__ __volatile__(
 140         "1:     ldl_l   %1,%0\n"
 141         "       lda     %2,0\n"
 142         "       bne     %1,2f\n"
 143         "       lda     %2,1\n"
 144         "       stl_c   %2,%0\n"
 145         "       beq     %2,6f\n"
 146         "2:     mb\n"
 147         ".subsection 2\n"
 148         "6:     br      1b\n"
 149         ".previous"
 150         : "=m" (*lock), "=&r" (regx), "=&r" (success)
 151         : "m" (*lock) : "memory");
 152
 153         return success;
 154 }
 155
 156 static inline void arch_read_unlock(arch_rwlock_t * lock)
 157 {
 158         long regx;
 159         __asm__ __volatile__(
 160         "       mb\n"
 161         "1:     ldl_l   %1,%0\n"
 162         "       addl    %1,2,%1\n"
 163         "       stl_c   %1,%0\n"
 164         "       beq     %1,6f\n"
 165         ".subsection 2\n"
 166         "6:     br      1b\n"
 167         ".previous"
 168         : "=m" (*lock), "=&r" (regx)
 169         : "m" (*lock) : "memory");
 170 }
 171
 172 static inline void arch_write_unlock(arch_rwlock_t * lock)
 173 {
 174         mb();
 175         lock->lock = 0;
 176 }
 177
 178 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 179 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 180
 181 #endif /* _ALPHA_SPINLOCK_H */