X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fpowerpc%2Flib%2Flocks.c;fp=arch%2Fpowerpc%2Flib%2Flocks.c;h=8362fa272ca58e9699c88c155c535a2e59fb4aeb;hb=16cf0ec7408f389279d413869e94c1a351392f97;hp=0000000000000000000000000000000000000000;hpb=65da6b7c3bf0bd6a149128079565e5f4efec28ac;p=linux-2.6.git

diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c
new file mode 100644
index 000000000..8362fa272
--- /dev/null
+++ b/arch/powerpc/lib/locks.c
@@ -0,0 +1,93 @@
+/*
+ * Spin and read/write 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
+ *
+ * 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 <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/stringify.h>
+#include <linux/smp.h>
+
+/* waiting for a spinlock... */
+#if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
+#include <asm/hvcall.h>
+#include <asm/iseries/hv_call.h>
+#include <asm/smp.h>
+
+void __spin_yield(raw_spinlock_t *lock)
+{
+	unsigned int lock_value, holder_cpu, yield_count;
+
+	lock_value = lock->slock;
+	if (lock_value == 0)
+		return;
+	holder_cpu = lock_value & 0xffff;
+	BUG_ON(holder_cpu >= NR_CPUS);
+	yield_count = lppaca[holder_cpu].yield_count;
+	if ((yield_count & 1) == 0)
+		return;		/* virtual cpu is currently running */
+	rmb();
+	if (lock->slock != lock_value)
+		return;		/* something has changed */
+#ifdef CONFIG_PPC_ISERIES
+	HvCall2(HvCallBaseYieldProcessor, HvCall_YieldToProc,
+		((u64)holder_cpu << 32) | yield_count);
+#else
+	plpar_hcall_norets(H_CONFER, get_hard_smp_processor_id(holder_cpu),
+			   yield_count);
+#endif
+}
+
+/*
+ * Waiting for a read lock or a write lock on a rwlock...
+ * This turns out to be the same for read and write locks, since
+ * we only know the holder if it is write-locked.
+ */
+void __rw_yield(raw_rwlock_t *rw)
+{
+	int lock_value;
+	unsigned int holder_cpu, yield_count;
+
+	lock_value = rw->lock;
+	if (lock_value >= 0)
+		return;		/* no write lock at present */
+	holder_cpu = lock_value & 0xffff;
+	BUG_ON(holder_cpu >= NR_CPUS);
+	yield_count = lppaca[holder_cpu].yield_count;
+	if ((yield_count & 1) == 0)
+		return;		/* virtual cpu is currently running */
+	rmb();
+	if (rw->lock != lock_value)
+		return;		/* something has changed */
+#ifdef CONFIG_PPC_ISERIES
+	HvCall2(HvCallBaseYieldProcessor, HvCall_YieldToProc,
+		((u64)holder_cpu << 32) | yield_count);
+#else
+	plpar_hcall_norets(H_CONFER, get_hard_smp_processor_id(holder_cpu),
+			   yield_count);
+#endif
+}
+#endif
+
+void __raw_spin_unlock_wait(raw_spinlock_t *lock)
+{
+	while (lock->slock) {
+		HMT_low();
+		if (SHARED_PROCESSOR)
+			__spin_yield(lock);
+	}
+	HMT_medium();
+}
+
+EXPORT_SYMBOL(__raw_spin_unlock_wait);