arch/alpha/include/asm/spinlock.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ALPHA_SPINLOCK_H
   3 #define _ALPHA_SPINLOCK_H
   4
   5 #include <linux/kernel.h>
   6 #include <asm/current.h>
   7 #include <asm/barrier.h>
   8 #include <asm/processor.h>
   9
  10 /*
  11  * Simple spin lock operations.  There are two variants, one clears IRQ's
  12  * on the local processor, one does not.
  13  *
  14  * We make no fairness assumptions. They have a cost.
  15  */
  16
  17 #define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
  18 #define arch_spin_is_locked(x)  ((x)->lock != 0)
  19
  20 static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
  21 {
  22         return lock.lock == 0;
  23 }
  24
  25 static inline void arch_spin_unlock(arch_spinlock_t * lock)
  26 {
  27         mb();
  28         lock->lock = 0;
  29 }
  30
  31 static inline void arch_spin_lock(arch_spinlock_t * lock)
  32 {
  33         long tmp;
  34
  35         __asm__ __volatile__(
  36         "1:     ldl_l   %0,%1\n"
  37         "       bne     %0,2f\n"
  38         "       lda     %0,1\n"
  39         "       stl_c   %0,%1\n"
  40         "       beq     %0,2f\n"
  41         "       mb\n"
  42         ".subsection 2\n"
  43         "2:     ldl     %0,%1\n"
  44         "       bne     %0,2b\n"
  45         "       br      1b\n"
  46         ".previous"
  47         : "=&r" (tmp), "=m" (lock->lock)
  48         : "m"(lock->lock) : "memory");
  49 }
  50
  51 static inline int arch_spin_trylock(arch_spinlock_t *lock)
  52 {
  53         return !test_and_set_bit(0, &lock->lock);
  54 }
  55
  56 /***********************************************************/
  57
  58 static inline int arch_read_can_lock(arch_rwlock_t *lock)
  59 {
  60         return (lock->lock & 1) == 0;
  61 }
  62
  63 static inline int arch_write_can_lock(arch_rwlock_t *lock)
  64 {
  65         return lock->lock == 0;
  66 }
  67
  68 static inline void arch_read_lock(arch_rwlock_t *lock)
  69 {
  70         long regx;
  71
  72         __asm__ __volatile__(
  73         "1:     ldl_l   %1,%0\n"
  74         "       blbs    %1,6f\n"
  75         "       subl    %1,2,%1\n"
  76         "       stl_c   %1,%0\n"
  77         "       beq     %1,6f\n"
  78         "       mb\n"
  79         ".subsection 2\n"
  80         "6:     ldl     %1,%0\n"
  81         "       blbs    %1,6b\n"
  82         "       br      1b\n"
  83         ".previous"
  84         : "=m" (*lock), "=&r" (regx)
  85         : "m" (*lock) : "memory");
  86 }
  87
  88 static inline void arch_write_lock(arch_rwlock_t *lock)
  89 {
  90         long regx;
  91
  92         __asm__ __volatile__(
  93         "1:     ldl_l   %1,%0\n"
  94         "       bne     %1,6f\n"
  95         "       lda     %1,1\n"
  96         "       stl_c   %1,%0\n"
  97         "       beq     %1,6f\n"
  98         "       mb\n"
  99         ".subsection 2\n"
 100         "6:     ldl     %1,%0\n"
 101         "       bne     %1,6b\n"
 102         "       br      1b\n"
 103         ".previous"
 104         : "=m" (*lock), "=&r" (regx)
 105         : "m" (*lock) : "memory");
 106 }
 107
 108 static inline int arch_read_trylock(arch_rwlock_t * lock)
 109 {
 110         long regx;
 111         int success;
 112
 113         __asm__ __volatile__(
 114         "1:     ldl_l   %1,%0\n"
 115         "       lda     %2,0\n"
 116         "       blbs    %1,2f\n"
 117         "       subl    %1,2,%2\n"
 118         "       stl_c   %2,%0\n"
 119         "       beq     %2,6f\n"
 120         "2:     mb\n"
 121         ".subsection 2\n"
 122         "6:     br      1b\n"
 123         ".previous"
 124         : "=m" (*lock), "=&r" (regx), "=&r" (success)
 125         : "m" (*lock) : "memory");
 126
 127         return success;
 128 }
 129
 130 static inline int arch_write_trylock(arch_rwlock_t * lock)
 131 {
 132         long regx;
 133         int success;
 134
 135         __asm__ __volatile__(
 136         "1:     ldl_l   %1,%0\n"
 137         "       lda     %2,0\n"
 138         "       bne     %1,2f\n"
 139         "       lda     %2,1\n"
 140         "       stl_c   %2,%0\n"
 141         "       beq     %2,6f\n"
 142         "2:     mb\n"
 143         ".subsection 2\n"
 144         "6:     br      1b\n"
 145         ".previous"
 146         : "=m" (*lock), "=&r" (regx), "=&r" (success)
 147         : "m" (*lock) : "memory");
 148
 149         return success;
 150 }
 151
 152 static inline void arch_read_unlock(arch_rwlock_t * lock)
 153 {
 154         long regx;
 155         __asm__ __volatile__(
 156         "       mb\n"
 157         "1:     ldl_l   %1,%0\n"
 158         "       addl    %1,2,%1\n"
 159         "       stl_c   %1,%0\n"
 160         "       beq     %1,6f\n"
 161         ".subsection 2\n"
 162         "6:     br      1b\n"
 163         ".previous"
 164         : "=m" (*lock), "=&r" (regx)
 165         : "m" (*lock) : "memory");
 166 }
 167
 168 static inline void arch_write_unlock(arch_rwlock_t * lock)
 169 {
 170         mb();
 171         lock->lock = 0;
 172 }
 173
 174 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 175 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 176
 177 #endif /* _ALPHA_SPINLOCK_H */