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Diffstat (limited to 'arch/powerpc/include/asm/qspinlock.h')
-rw-r--r--arch/powerpc/include/asm/qspinlock.h24
1 files changed, 19 insertions, 5 deletions
diff --git a/arch/powerpc/include/asm/qspinlock.h b/arch/powerpc/include/asm/qspinlock.h
index 713f6629f6fb..c16e1f0674b5 100644
--- a/arch/powerpc/include/asm/qspinlock.h
+++ b/arch/powerpc/include/asm/qspinlock.h
@@ -2,29 +2,43 @@
#ifndef _ASM_POWERPC_QSPINLOCK_H
#define _ASM_POWERPC_QSPINLOCK_H
-#include <linux/atomic.h>
#include <linux/compiler.h>
#include <asm/qspinlock_types.h>
#include <asm/paravirt.h>
static __always_inline int queued_spin_is_locked(struct qspinlock *lock)
{
- return atomic_read(&lock->val);
+ return READ_ONCE(lock->val);
}
static __always_inline int queued_spin_value_unlocked(struct qspinlock lock)
{
- return !atomic_read(&lock.val);
+ return !lock.val;
}
static __always_inline int queued_spin_is_contended(struct qspinlock *lock)
{
- return !!(atomic_read(&lock->val) & _Q_TAIL_CPU_MASK);
+ return !!(READ_ONCE(lock->val) & _Q_TAIL_CPU_MASK);
}
static __always_inline int queued_spin_trylock(struct qspinlock *lock)
{
- return atomic_cmpxchg_acquire(&lock->val, 0, _Q_LOCKED_VAL) == 0;
+ u32 prev;
+
+ asm volatile(
+"1: lwarx %0,0,%1,%3 # queued_spin_trylock \n"
+" cmpwi 0,%0,0 \n"
+" bne- 2f \n"
+" stwcx. %2,0,%1 \n"
+" bne- 1b \n"
+"\t" PPC_ACQUIRE_BARRIER " \n"
+"2: \n"
+ : "=&r" (prev)
+ : "r" (&lock->val), "r" (_Q_LOCKED_VAL),
+ "i" (IS_ENABLED(CONFIG_PPC64))
+ : "cr0", "memory");
+
+ return likely(prev == 0);
}
void queued_spin_lock_slowpath(struct qspinlock *lock);