include/asm/spinlock.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 #ifndef _ALPHA_SPINLOCK_H
0003 #define _ALPHA_SPINLOCK_H
0004
0005 #include <linux/kernel.h>
0006 #include <asm/current.h>
0007 #include <asm/barrier.h>
0008 #include <asm/processor.h>
0009
0010 /*
0011  * Simple spin lock operations.  There are two variants, one clears IRQ's
0012  * on the local processor, one does not.
0013  *
0014  * We make no fairness assumptions. They have a cost.
0015  */
0016
0017 #define arch_spin_is_locked(x)  ((x)->lock != 0)
0018
0019 static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
0020 {
0021         return lock.lock == 0;
0022 }
0023
0024 static inline void arch_spin_unlock(arch_spinlock_t * lock)
0025 {
0026     mb();
0027     lock->lock = 0;
0028 }
0029
0030 static inline void arch_spin_lock(arch_spinlock_t * lock)
0031 {
0032     long tmp;
0033
0034     __asm__ __volatile__(
0035     "1: ldl_l   %0,%1\n"
0036     "   bne %0,2f\n"
0037     "   lda %0,1\n"
0038     "   stl_c   %0,%1\n"
0039     "   beq %0,2f\n"
0040     "   mb\n"
0041     ".subsection 2\n"
0042     "2: ldl %0,%1\n"
0043     "   bne %0,2b\n"
0044     "   br  1b\n"
0045     ".previous"
0046     : "=&r" (tmp), "=m" (lock->lock)
0047     : "m"(lock->lock) : "memory");
0048 }
0049
0050 static inline int arch_spin_trylock(arch_spinlock_t *lock)
0051 {
0052     return !test_and_set_bit(0, &lock->lock);
0053 }
0054
0055 /***********************************************************/
0056
0057 static inline void arch_read_lock(arch_rwlock_t *lock)
0058 {
0059     long regx;
0060
0061     __asm__ __volatile__(
0062     "1: ldl_l   %1,%0\n"
0063     "   blbs    %1,6f\n"
0064     "   subl    %1,2,%1\n"
0065     "   stl_c   %1,%0\n"
0066     "   beq %1,6f\n"
0067     "   mb\n"
0068     ".subsection 2\n"
0069     "6: ldl %1,%0\n"
0070     "   blbs    %1,6b\n"
0071     "   br  1b\n"
0072     ".previous"
0073     : "=m" (*lock), "=&r" (regx)
0074     : "m" (*lock) : "memory");
0075 }
0076
0077 static inline void arch_write_lock(arch_rwlock_t *lock)
0078 {
0079     long regx;
0080
0081     __asm__ __volatile__(
0082     "1: ldl_l   %1,%0\n"
0083     "   bne %1,6f\n"
0084     "   lda %1,1\n"
0085     "   stl_c   %1,%0\n"
0086     "   beq %1,6f\n"
0087     "   mb\n"
0088     ".subsection 2\n"
0089     "6: ldl %1,%0\n"
0090     "   bne %1,6b\n"
0091     "   br  1b\n"
0092     ".previous"
0093     : "=m" (*lock), "=&r" (regx)
0094     : "m" (*lock) : "memory");
0095 }
0096
0097 static inline int arch_read_trylock(arch_rwlock_t * lock)
0098 {
0099     long regx;
0100     int success;
0101
0102     __asm__ __volatile__(
0103     "1: ldl_l   %1,%0\n"
0104     "   lda %2,0\n"
0105     "   blbs    %1,2f\n"
0106     "   subl    %1,2,%2\n"
0107     "   stl_c   %2,%0\n"
0108     "   beq %2,6f\n"
0109     "2: mb\n"
0110     ".subsection 2\n"
0111     "6: br  1b\n"
0112     ".previous"
0113     : "=m" (*lock), "=&r" (regx), "=&r" (success)
0114     : "m" (*lock) : "memory");
0115
0116     return success;
0117 }
0118
0119 static inline int arch_write_trylock(arch_rwlock_t * lock)
0120 {
0121     long regx;
0122     int success;
0123
0124     __asm__ __volatile__(
0125     "1: ldl_l   %1,%0\n"
0126     "   lda %2,0\n"
0127     "   bne %1,2f\n"
0128     "   lda %2,1\n"
0129     "   stl_c   %2,%0\n"
0130     "   beq %2,6f\n"
0131     "2: mb\n"
0132     ".subsection 2\n"
0133     "6: br  1b\n"
0134     ".previous"
0135     : "=m" (*lock), "=&r" (regx), "=&r" (success)
0136     : "m" (*lock) : "memory");
0137
0138     return success;
0139 }
0140
0141 static inline void arch_read_unlock(arch_rwlock_t * lock)
0142 {
0143     long regx;
0144     __asm__ __volatile__(
0145     "   mb\n"
0146     "1: ldl_l   %1,%0\n"
0147     "   addl    %1,2,%1\n"
0148     "   stl_c   %1,%0\n"
0149     "   beq %1,6f\n"
0150     ".subsection 2\n"
0151     "6: br  1b\n"
0152     ".previous"
0153     : "=m" (*lock), "=&r" (regx)
0154     : "m" (*lock) : "memory");
0155 }
0156
0157 static inline void arch_write_unlock(arch_rwlock_t * lock)
0158 {
0159     mb();
0160     lock->lock = 0;
0161 }
0162
0163 #endif /* _ALPHA_SPINLOCK_H */