diff options
Diffstat (limited to 'arch/arm64/include/asm/spinlock.h')
-rw-r--r-- | arch/arm64/include/asm/spinlock.h | 173 |
1 files changed, 1 insertions, 172 deletions
diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h index 95ad7102b63c..fdb827c7832f 100644 --- a/arch/arm64/include/asm/spinlock.h +++ b/arch/arm64/include/asm/spinlock.h @@ -27,8 +27,6 @@ * instructions. */ -#define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock) - static inline void arch_spin_lock(arch_spinlock_t *lock) { unsigned int tmp; @@ -139,176 +137,7 @@ static inline int arch_spin_is_contended(arch_spinlock_t *lock) } #define arch_spin_is_contended arch_spin_is_contended -/* - * Write lock implementation. - * - * Write locks set bit 31. Unlocking, is done by writing 0 since the lock is - * exclusively held. - * - * The memory barriers are implicit with the load-acquire and store-release - * instructions. - */ - -static inline void arch_write_lock(arch_rwlock_t *rw) -{ - unsigned int tmp; - - asm volatile(ARM64_LSE_ATOMIC_INSN( - /* LL/SC */ - " sevl\n" - "1: wfe\n" - "2: ldaxr %w0, %1\n" - " cbnz %w0, 1b\n" - " stxr %w0, %w2, %1\n" - " cbnz %w0, 2b\n" - __nops(1), - /* LSE atomics */ - "1: mov %w0, wzr\n" - "2: casa %w0, %w2, %1\n" - " cbz %w0, 3f\n" - " ldxr %w0, %1\n" - " cbz %w0, 2b\n" - " wfe\n" - " b 1b\n" - "3:") - : "=&r" (tmp), "+Q" (rw->lock) - : "r" (0x80000000) - : "memory"); -} - -static inline int arch_write_trylock(arch_rwlock_t *rw) -{ - unsigned int tmp; - - asm volatile(ARM64_LSE_ATOMIC_INSN( - /* LL/SC */ - "1: ldaxr %w0, %1\n" - " cbnz %w0, 2f\n" - " stxr %w0, %w2, %1\n" - " cbnz %w0, 1b\n" - "2:", - /* LSE atomics */ - " mov %w0, wzr\n" - " casa %w0, %w2, %1\n" - __nops(2)) - : "=&r" (tmp), "+Q" (rw->lock) - : "r" (0x80000000) - : "memory"); - - return !tmp; -} - -static inline void arch_write_unlock(arch_rwlock_t *rw) -{ - asm volatile(ARM64_LSE_ATOMIC_INSN( - " stlr wzr, %0", - " swpl wzr, wzr, %0") - : "=Q" (rw->lock) :: "memory"); -} - -/* write_can_lock - would write_trylock() succeed? */ -#define arch_write_can_lock(x) ((x)->lock == 0) - -/* - * Read lock implementation. - * - * It exclusively loads the lock value, increments it and stores the new value - * back if positive and the CPU still exclusively owns the location. If the - * value is negative, the lock is already held. - * - * During unlocking there may be multiple active read locks but no write lock. - * - * The memory barriers are implicit with the load-acquire and store-release - * instructions. - * - * Note that in UNDEFINED cases, such as unlocking a lock twice, the LL/SC - * and LSE implementations may exhibit different behaviour (although this - * will have no effect on lockdep). - */ -static inline void arch_read_lock(arch_rwlock_t *rw) -{ - unsigned int tmp, tmp2; - - asm volatile( - " sevl\n" - ARM64_LSE_ATOMIC_INSN( - /* LL/SC */ - "1: wfe\n" - "2: ldaxr %w0, %2\n" - " add %w0, %w0, #1\n" - " tbnz %w0, #31, 1b\n" - " stxr %w1, %w0, %2\n" - " cbnz %w1, 2b\n" - __nops(1), - /* LSE atomics */ - "1: wfe\n" - "2: ldxr %w0, %2\n" - " adds %w1, %w0, #1\n" - " tbnz %w1, #31, 1b\n" - " casa %w0, %w1, %2\n" - " sbc %w0, %w1, %w0\n" - " cbnz %w0, 2b") - : "=&r" (tmp), "=&r" (tmp2), "+Q" (rw->lock) - : - : "cc", "memory"); -} - -static inline void arch_read_unlock(arch_rwlock_t *rw) -{ - unsigned int tmp, tmp2; - - asm volatile(ARM64_LSE_ATOMIC_INSN( - /* LL/SC */ - "1: ldxr %w0, %2\n" - " sub %w0, %w0, #1\n" - " stlxr %w1, %w0, %2\n" - " cbnz %w1, 1b", - /* LSE atomics */ - " movn %w0, #0\n" - " staddl %w0, %2\n" - __nops(2)) - : "=&r" (tmp), "=&r" (tmp2), "+Q" (rw->lock) - : - : "memory"); -} - -static inline int arch_read_trylock(arch_rwlock_t *rw) -{ - unsigned int tmp, tmp2; - - asm volatile(ARM64_LSE_ATOMIC_INSN( - /* LL/SC */ - " mov %w1, #1\n" - "1: ldaxr %w0, %2\n" - " add %w0, %w0, #1\n" - " tbnz %w0, #31, 2f\n" - " stxr %w1, %w0, %2\n" - " cbnz %w1, 1b\n" - "2:", - /* LSE atomics */ - " ldr %w0, %2\n" - " adds %w1, %w0, #1\n" - " tbnz %w1, #31, 1f\n" - " casa %w0, %w1, %2\n" - " sbc %w1, %w1, %w0\n" - __nops(1) - "1:") - : "=&r" (tmp), "=&r" (tmp2), "+Q" (rw->lock) - : - : "cc", "memory"); - - return !tmp2; -} - -/* read_can_lock - would read_trylock() succeed? */ -#define arch_read_can_lock(x) ((x)->lock < 0x80000000) - -#define arch_read_lock_flags(lock, flags) arch_read_lock(lock) -#define arch_write_lock_flags(lock, flags) arch_write_lock(lock) - -#define arch_spin_relax(lock) cpu_relax() -#define arch_read_relax(lock) cpu_relax() -#define arch_write_relax(lock) cpu_relax() +#include <asm/qrwlock.h> /* See include/linux/spinlock.h */ #define smp_mb__after_spinlock() smp_mb() |