Add MP lock support for OpenBSD/hppa.

ok kettenis@

3 files changed, 261 insertions, 1 deletions

diff --git a/sys/arch/hppa/conf/files.hppa b/sys/arch/hppa/conf/files.hppa
index 88d641f032d..dfbb5dc7609 100644
--- a/sys/arch/hppa/conf/files.hppa
+++ b/sys/arch/hppa/conf/files.hppa
@@ -1,4 +1,4 @@
-#	$OpenBSD: files.hppa,v 1.80 2008/07/16 16:32:08 miod Exp $
+#	$OpenBSD: files.hppa,v 1.81 2010/03/25 14:26:21 jsing Exp $
 #
 # hppa-specific configuration info
 
@@ -307,6 +307,7 @@ file	arch/hppa/hppa/conf.c
 file	arch/hppa/hppa/db_interface.c		ddb
 file	arch/hppa/hppa/db_disasm.c		ddb
 file	arch/hppa/hppa/disksubr.c		disk
+file	arch/hppa/hppa/lock_machdep.c		multiprocessor
 file	arch/hppa/hppa/machdep.c
 file	arch/hppa/hppa/mutex.c
 file	arch/hppa/hppa/pmap.c
diff --git a/sys/arch/hppa/hppa/lock_machdep.c b/sys/arch/hppa/hppa/lock_machdep.c
new file mode 100644
index 00000000000..1480ae45f6d
--- /dev/null
+++ b/sys/arch/hppa/hppa/lock_machdep.c
@@ -0,0 +1,203 @@
+/*	$OpenBSD: lock_machdep.c,v 1.1 2010/03/25 14:26:21 jsing Exp $	*/
+
+/*
+ * Copyright (c) 2007 Artur Grabowski <art@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/lock.h>
+#include <sys/systm.h>
+
+#include <machine/atomic.h>
+#include <machine/intr.h>
+#include <machine/lock.h>
+#include <machine/psl.h>
+
+#include <ddb/db_output.h>
+
+static __inline int
+__cpu_cas(struct __mp_lock *mpl, volatile unsigned long *addr,
+    unsigned long old, unsigned long new)
+{
+	volatile int *lock = (int *)(((vaddr_t)mpl->mpl_lock + 0xf) & ~0xf);
+	volatile register_t locked = 0;
+	int ret = 1;
+
+	/* Note: lock must be 16-byte aligned. */
+	asm volatile (
+		"ldcws      0(%2), %0"
+		: "=&r" (locked), "+m" (lock)
+		: "r" (lock)
+	);
+
+	if (locked == MPL_LOCKED) {
+		if (*addr == old) {
+			*addr = new;
+			asm("sync" ::: "memory");
+			ret = 0;
+		}
+		*lock = MPL_UNLOCKED;
+	}
+
+	return ret;
+}
+
+void
+__mp_lock_init(struct __mp_lock *lock)
+{
+	lock->mpl_lock[0] = MPL_UNLOCKED;
+	lock->mpl_lock[1] = MPL_UNLOCKED;
+	lock->mpl_lock[2] = MPL_UNLOCKED;
+	lock->mpl_lock[3] = MPL_UNLOCKED;
+	lock->mpl_cpu = NULL;
+	lock->mpl_count = 0;
+}
+
+#if defined(MP_LOCKDEBUG)
+#ifndef DDB
+#error "MP_LOCKDEBUG requires DDB"
+#endif
+
+/* CPU-dependent timing, this needs to be settable from ddb. */
+extern int __mp_lock_spinout;
+#endif
+
+#define SPINLOCK_SPIN_HOOK	/**/
+
+static __inline void
+__mp_lock_spin(struct __mp_lock *mpl)
+{
+#ifndef MP_LOCKDEBUG
+	while (mpl->mpl_count != 0)
+		SPINLOCK_SPIN_HOOK;
+#else
+	int ticks = __mp_lock_spinout;
+
+	while (mpl->mpl_count != 0 && ticks-- > 0)
+		SPINLOCK_SPIN_HOOK;
+
+	if (ticks == 0) {
+		db_printf("__mp_lock(0x%x): lock spun out", mpl);
+		Debugger();
+	}
+#endif
+}
+
+void
+__mp_lock(struct __mp_lock *mpl)
+{
+	int s;
+
+	/*
+	 * Please notice that mpl_count gets incremented twice for the
+	 * first lock. This is on purpose. The way we release the lock
+	 * in mp_unlock is to decrement the mpl_count and then check if
+	 * the lock should be released. Since mpl_count is what we're
+	 * spinning on, decrementing it in mpl_unlock to 0 means that
+	 * we can't clear mpl_cpu, because we're no longer holding the
+	 * lock. In theory mpl_cpu doesn't need to be cleared, but it's
+	 * safer to clear it and besides, setting mpl_count to 2 on the
+	 * first lock makes most of this code much simpler.
+	 */
+
+	while (1) {
+		s = hppa_intr_disable();
+		if (__cpu_cas(mpl, &mpl->mpl_count, 0, 1) == 0) {
+			__asm __volatile("sync" ::: "memory");
+			mpl->mpl_cpu = curcpu();
+		}
+		if (mpl->mpl_cpu == curcpu()) {
+			mpl->mpl_count++;
+			hppa_intr_enable(s);
+			break;
+		}
+		hppa_intr_enable(s);
+
+		__mp_lock_spin(mpl);
+	}
+}
+
+void
+__mp_unlock(struct __mp_lock *mpl)
+{
+	int s;
+
+#ifdef MP_LOCKDEBUG
+	if (mpl->mpl_cpu != curcpu()) {
+		db_printf("__mp_unlock(%p): not held lock\n", mpl);
+		Debugger();
+	}
+#endif
+
+	s = hppa_intr_disable();
+	if (--mpl->mpl_count == 1) {
+		mpl->mpl_cpu = NULL;
+		__asm __volatile("sync" ::: "memory");
+		mpl->mpl_count = 0;
+	}
+	hppa_intr_enable(s);
+}
+
+int
+__mp_release_all(struct __mp_lock *mpl)
+{
+	int rv = mpl->mpl_count - 1;
+	int s;
+
+#ifdef MP_LOCKDEBUG
+	if (mpl->mpl_cpu != curcpu()) {
+		db_printf("__mp_release_all(%p): not held lock\n", mpl);
+		Debugger();
+	}
+#endif
+
+	s = hppa_intr_disable();
+	mpl->mpl_cpu = NULL;
+	__asm __volatile("sync" ::: "memory");
+	mpl->mpl_count = 0;
+	hppa_intr_enable(s);
+
+	return (rv);
+}
+
+int
+__mp_release_all_but_one(struct __mp_lock *mpl)
+{
+	int rv = mpl->mpl_count - 2;
+
+#ifdef MP_LOCKDEBUG
+	if (mpl->mpl_cpu != curcpu()) {
+		db_printf("__mp_release_all_but_one(%p): not held lock\n", mpl);
+		Debugger();
+	}
+#endif
+
+	mpl->mpl_count = 2;
+
+	return (rv);
+}
+
+void
+__mp_acquire_count(struct __mp_lock *mpl, int count)
+{
+	while (count--)
+		__mp_lock(mpl);
+}
+
+int
+__mp_lock_held(struct __mp_lock *mpl)
+{
+	return mpl->mpl_cpu == curcpu();
+}
diff --git a/sys/arch/hppa/include/mplock.h b/sys/arch/hppa/include/mplock.h
new file mode 100644
index 00000000000..ec5bb03c16d
--- /dev/null
+++ b/sys/arch/hppa/include/mplock.h
@@ -0,0 +1,56 @@
+/*	$OpenBSD: mplock.h,v 1.1 2010/03/25 14:26:21 jsing Exp $	*/
+
+/*
+ * Copyright (c) 2004 Niklas Hallqvist.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _MACHINE_MPLOCK_H_
+#define _MACHINE_MPLOCK_H_
+
+/*
+ * Really simple spinlock implementation with recursive capabilities.
+ * Correctness is paramount, no fancyness allowed.
+ */
+
+#define	MPL_LOCKED	0
+#define	MPL_UNLOCKED	1
+
+struct __mp_lock {
+	volatile int mpl_lock[4];
+	volatile struct cpu_info *mpl_cpu;
+	volatile long mpl_count;
+};
+
+#ifndef _LOCORE
+
+void __mp_lock_init(struct __mp_lock *);
+void __mp_lock(struct __mp_lock *);
+void __mp_unlock(struct __mp_lock *);
+int __mp_release_all(struct __mp_lock *);
+int __mp_release_all_but_one(struct __mp_lock *);
+void __mp_acquire_count(struct __mp_lock *, int);
+int __mp_lock_held(struct __mp_lock *);
+
+#endif
+
+#endif /* !_MACHINE_MPLOCK_H */