1 files changed, 178 insertions, 0 deletions
diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h
new file mode 100644
index 000000000000..df84ae96915f
--- /dev/null
+++ b/arch/s390/include/asm/spinlock.h
@@ -0,0 +1,178 @@
+/*
+ *  include/asm-s390/spinlock.h
+ *
+ *  S390 version
+ *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
+ *
+ *  Derived from "include/asm-i386/spinlock.h"
+ */
+
+#ifndef __ASM_SPINLOCK_H
+#define __ASM_SPINLOCK_H
+
+#include <linux/smp.h>
+
+#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
+
+static inline int
+_raw_compare_and_swap(volatile unsigned int *lock,
+		      unsigned int old, unsigned int new)
+{
+	asm volatile(
+		"	cs	%0,%3,%1"
+		: "=d" (old), "=Q" (*lock)
+		: "0" (old), "d" (new), "Q" (*lock)
+		: "cc", "memory" );
+	return old;
+}
+
+#else /* __GNUC__ */
+
+static inline int
+_raw_compare_and_swap(volatile unsigned int *lock,
+		      unsigned int old, unsigned int new)
+{
+	asm volatile(
+		"	cs	%0,%3,0(%4)"
+		: "=d" (old), "=m" (*lock)
+		: "0" (old), "d" (new), "a" (lock), "m" (*lock)
+		: "cc", "memory" );
+	return old;
+}
+
+#endif /* __GNUC__ */
+
+/*
+ * Simple spin lock operations.  There are two variants, one clears IRQ's
+ * on the local processor, one does not.
+ *
+ * We make no fairness assumptions. They have a cost.
+ *
+ * (the type definitions are in asm/spinlock_types.h)
+ */
+
+#define __raw_spin_is_locked(x) ((x)->owner_cpu != 0)
+#define __raw_spin_unlock_wait(lock) \
+	do { while (__raw_spin_is_locked(lock)) \
+		 _raw_spin_relax(lock); } while (0)
+
+extern void _raw_spin_lock_wait(raw_spinlock_t *);
+extern void _raw_spin_lock_wait_flags(raw_spinlock_t *, unsigned long flags);
+extern int _raw_spin_trylock_retry(raw_spinlock_t *);
+extern void _raw_spin_relax(raw_spinlock_t *lock);
+
+static inline void __raw_spin_lock(raw_spinlock_t *lp)
+{
+	int old;
+
+	old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
+	if (likely(old == 0))
+		return;
+	_raw_spin_lock_wait(lp);
+}
+
+static inline void __raw_spin_lock_flags(raw_spinlock_t *lp,
+					 unsigned long flags)
+{
+	int old;
+
+	old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
+	if (likely(old == 0))
+		return;
+	_raw_spin_lock_wait_flags(lp, flags);
+}
+
+static inline int __raw_spin_trylock(raw_spinlock_t *lp)
+{
+	int old;
+
+	old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
+	if (likely(old == 0))
+		return 1;
+	return _raw_spin_trylock_retry(lp);
+}
+
+static inline void __raw_spin_unlock(raw_spinlock_t *lp)
+{
+	_raw_compare_and_swap(&lp->owner_cpu, lp->owner_cpu, 0);
+}
+		
+/*
+ * Read-write spinlocks, allowing multiple readers
+ * but only one writer.
+ *
+ * NOTE! it is quite common to have readers in interrupts
+ * but no interrupt writers. For those circumstances we
+ * can "mix" irq-safe locks - any writer needs to get a
+ * irq-safe write-lock, but readers can get non-irqsafe
+ * read-locks.
+ */
+
+/**
+ * read_can_lock - would read_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+#define __raw_read_can_lock(x) ((int)(x)->lock >= 0)
+
+/**
+ * write_can_lock - would write_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+#define __raw_write_can_lock(x) ((x)->lock == 0)
+
+extern void _raw_read_lock_wait(raw_rwlock_t *lp);
+extern int _raw_read_trylock_retry(raw_rwlock_t *lp);
+extern void _raw_write_lock_wait(raw_rwlock_t *lp);
+extern int _raw_write_trylock_retry(raw_rwlock_t *lp);
+
+static inline void __raw_read_lock(raw_rwlock_t *rw)
+{
+	unsigned int old;
+	old = rw->lock & 0x7fffffffU;
+	if (_raw_compare_and_swap(&rw->lock, old, old + 1) != old)
+		_raw_read_lock_wait(rw);
+}
+
+static inline void __raw_read_unlock(raw_rwlock_t *rw)
+{
+	unsigned int old, cmp;
+
+	old = rw->lock;
+	do {
+		cmp = old;
+		old = _raw_compare_and_swap(&rw->lock, old, old - 1);
+	} while (cmp != old);
+}
+
+static inline void __raw_write_lock(raw_rwlock_t *rw)
+{
+	if (unlikely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) != 0))
+		_raw_write_lock_wait(rw);
+}
+
+static inline void __raw_write_unlock(raw_rwlock_t *rw)
+{
+	_raw_compare_and_swap(&rw->lock, 0x80000000, 0);
+}
+
+static inline int __raw_read_trylock(raw_rwlock_t *rw)
+{
+	unsigned int old;
+	old = rw->lock & 0x7fffffffU;
+	if (likely(_raw_compare_and_swap(&rw->lock, old, old + 1) == old))
+		return 1;
+	return _raw_read_trylock_retry(rw);
+}
+
+static inline int __raw_write_trylock(raw_rwlock_t *rw)
+{
+	if (likely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0))
+		return 1;
+	return _raw_write_trylock_retry(rw);
+}
+
+#define _raw_read_relax(lock)	cpu_relax()
+#define _raw_write_relax(lock)	cpu_relax()
+
+#endif /* __ASM_SPINLOCK_H */