1 files changed, 260 insertions, 0 deletions
diff --git a/include/asm-ppc64/spinlock.h b/include/asm-ppc64/spinlock.h
new file mode 100644
index 00000000000..a9b2a1162cf
--- /dev/null
+++ b/include/asm-ppc64/spinlock.h
@@ -0,0 +1,260 @@
+#ifndef __ASM_SPINLOCK_H
+#define __ASM_SPINLOCK_H
+
+/*
+ * Simple spin lock operations.  
+ *
+ * Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM
+ * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
+ * Copyright (C) 2002 Dave Engebretsen <engebret@us.ibm.com>, IBM
+ *	Rework to support virtual processors
+ *
+ * Type of int is used as a full 64b word is not necessary.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <linux/config.h>
+#include <asm/paca.h>
+#include <asm/hvcall.h>
+#include <asm/iSeries/HvCall.h>
+
+typedef struct {
+	volatile unsigned int lock;
+#ifdef CONFIG_PREEMPT
+	unsigned int break_lock;
+#endif
+} spinlock_t;
+
+typedef struct {
+	volatile signed int lock;
+#ifdef CONFIG_PREEMPT
+	unsigned int break_lock;
+#endif
+} rwlock_t;
+
+#ifdef __KERNEL__
+#define SPIN_LOCK_UNLOCKED	(spinlock_t) { 0 }
+
+#define spin_is_locked(x)	((x)->lock != 0)
+#define spin_lock_init(x)	do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
+
+static __inline__ void _raw_spin_unlock(spinlock_t *lock)
+{
+	__asm__ __volatile__("lwsync	# spin_unlock": : :"memory");
+	lock->lock = 0;
+}
+
+/*
+ * On a system with shared processors (that is, where a physical
+ * processor is multiplexed between several virtual processors),
+ * there is no point spinning on a lock if the holder of the lock
+ * isn't currently scheduled on a physical processor.  Instead
+ * we detect this situation and ask the hypervisor to give the
+ * rest of our timeslice to the lock holder.
+ *
+ * So that we can tell which virtual processor is holding a lock,
+ * we put 0x80000000 | smp_processor_id() in the lock when it is
+ * held.  Conveniently, we have a word in the paca that holds this
+ * value.
+ */
+
+#if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
+/* We only yield to the hypervisor if we are in shared processor mode */
+#define SHARED_PROCESSOR (get_paca()->lppaca.shared_proc)
+extern void __spin_yield(spinlock_t *lock);
+extern void __rw_yield(rwlock_t *lock);
+#else /* SPLPAR || ISERIES */
+#define __spin_yield(x)	barrier()
+#define __rw_yield(x)	barrier()
+#define SHARED_PROCESSOR	0
+#endif
+extern void spin_unlock_wait(spinlock_t *lock);
+
+/*
+ * This returns the old value in the lock, so we succeeded
+ * in getting the lock if the return value is 0.
+ */
+static __inline__ unsigned long __spin_trylock(spinlock_t *lock)
+{
+	unsigned long tmp, tmp2;
+
+	__asm__ __volatile__(
+"	lwz		%1,%3(13)		# __spin_trylock\n\
+1:	lwarx		%0,0,%2\n\
+	cmpwi		0,%0,0\n\
+	bne-		2f\n\
+	stwcx.		%1,0,%2\n\
+	bne-		1b\n\
+	isync\n\
+2:"	: "=&r" (tmp), "=&r" (tmp2)
+	: "r" (&lock->lock), "i" (offsetof(struct paca_struct, lock_token))
+	: "cr0", "memory");
+
+	return tmp;
+}
+
+static int __inline__ _raw_spin_trylock(spinlock_t *lock)
+{
+	return __spin_trylock(lock) == 0;
+}
+
+static void __inline__ _raw_spin_lock(spinlock_t *lock)
+{
+	while (1) {
+		if (likely(__spin_trylock(lock) == 0))
+			break;
+		do {
+			HMT_low();
+			if (SHARED_PROCESSOR)
+				__spin_yield(lock);
+		} while (likely(lock->lock != 0));
+		HMT_medium();
+	}
+}
+
+static void __inline__ _raw_spin_lock_flags(spinlock_t *lock, unsigned long flags)
+{
+	unsigned long flags_dis;
+
+	while (1) {
+		if (likely(__spin_trylock(lock) == 0))
+			break;
+		local_save_flags(flags_dis);
+		local_irq_restore(flags);
+		do {
+			HMT_low();
+			if (SHARED_PROCESSOR)
+				__spin_yield(lock);
+		} while (likely(lock->lock != 0));
+		HMT_medium();
+		local_irq_restore(flags_dis);
+	}
+}
+
+/*
+ * 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.
+ */
+#define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
+
+#define rwlock_init(x)		do { *(x) = RW_LOCK_UNLOCKED; } while(0)
+
+#define read_can_lock(rw)	((rw)->lock >= 0)
+#define write_can_lock(rw)	(!(rw)->lock)
+
+static __inline__ void _raw_write_unlock(rwlock_t *rw)
+{
+	__asm__ __volatile__("lwsync		# write_unlock": : :"memory");
+	rw->lock = 0;
+}
+
+/*
+ * This returns the old value in the lock + 1,
+ * so we got a read lock if the return value is > 0.
+ */
+static long __inline__ __read_trylock(rwlock_t *rw)
+{
+	long tmp;
+
+	__asm__ __volatile__(
+"1:	lwarx		%0,0,%1		# read_trylock\n\
+	extsw		%0,%0\n\
+	addic.		%0,%0,1\n\
+	ble-		2f\n\
+	stwcx.		%0,0,%1\n\
+	bne-		1b\n\
+	isync\n\
+2:"	: "=&r" (tmp)
+	: "r" (&rw->lock)
+	: "cr0", "xer", "memory");
+
+	return tmp;
+}
+
+static int __inline__ _raw_read_trylock(rwlock_t *rw)
+{
+	return __read_trylock(rw) > 0;
+}
+
+static void __inline__ _raw_read_lock(rwlock_t *rw)
+{
+	while (1) {
+		if (likely(__read_trylock(rw) > 0))
+			break;
+		do {
+			HMT_low();
+			if (SHARED_PROCESSOR)
+				__rw_yield(rw);
+		} while (likely(rw->lock < 0));
+		HMT_medium();
+	}
+}
+
+static void __inline__ _raw_read_unlock(rwlock_t *rw)
+{
+	long tmp;
+
+	__asm__ __volatile__(
+	"eieio				# read_unlock\n\
+1:	lwarx		%0,0,%1\n\
+	addic		%0,%0,-1\n\
+	stwcx.		%0,0,%1\n\
+	bne-		1b"
+	: "=&r"(tmp)
+	: "r"(&rw->lock)
+	: "cr0", "memory");
+}
+
+/*
+ * This returns the old value in the lock,
+ * so we got the write lock if the return value is 0.
+ */
+static __inline__ long __write_trylock(rwlock_t *rw)
+{
+	long tmp, tmp2;
+
+	__asm__ __volatile__(
+"	lwz		%1,%3(13)	# write_trylock\n\
+1:	lwarx		%0,0,%2\n\
+	cmpwi		0,%0,0\n\
+	bne-		2f\n\
+	stwcx.		%1,0,%2\n\
+	bne-		1b\n\
+	isync\n\
+2:"	: "=&r" (tmp), "=&r" (tmp2)
+	: "r" (&rw->lock), "i" (offsetof(struct paca_struct, lock_token))
+	: "cr0", "memory");
+
+	return tmp;
+}
+
+static int __inline__ _raw_write_trylock(rwlock_t *rw)
+{
+	return __write_trylock(rw) == 0;
+}
+
+static void __inline__ _raw_write_lock(rwlock_t *rw)
+{
+	while (1) {
+		if (likely(__write_trylock(rw) == 0))
+			break;
+		do {
+			HMT_low();
+			if (SHARED_PROCESSOR)
+				__rw_yield(rw);
+		} while (likely(rw->lock != 0));
+		HMT_medium();
+	}
+}
+
+#endif /* __KERNEL__ */
+#endif /* __ASM_SPINLOCK_H */