diff --git a/sys/arch/alpha/alpha/machdep.c b/sys/arch/alpha/alpha/machdep.c
index e282b3700876..59d453b62516 100644
--- a/sys/arch/alpha/alpha/machdep.c
+++ b/sys/arch/alpha/alpha/machdep.c
@@ -1,4 +1,4 @@
-/* $NetBSD: machdep.c,v 1.286 2005/06/03 15:06:40 jdc Exp $ */
+/* $NetBSD: machdep.c,v 1.287 2005/07/28 13:57:06 thorpej Exp $ */
 
 /*-
  * Copyright (c) 1998, 1999, 2000 The NetBSD Foundation, Inc.
@@ -75,7 +75,7 @@
 
 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
 
-__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.286 2005/06/03 15:06:40 jdc Exp $");
+__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.287 2005/07/28 13:57:06 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1706,6 +1706,7 @@ fpusave_cpu(struct cpu_info *ci, int save)
 	KDASSERT(ci == curcpu());
 
 #if defined(MULTIPROCESSOR)
+	s = splhigh();		/* block IPIs for the duration */
 	atomic_setbits_ulong(&ci->ci_flags, CPUF_FPUSAVE);
 #endif
 
@@ -1720,16 +1721,17 @@ fpusave_cpu(struct cpu_info *ci, int save)
 
 	alpha_pal_wrfen(0);
 
-	FPCPU_LOCK(&l->l_addr->u_pcb, s);
+	FPCPU_LOCK(&l->l_addr->u_pcb);
 
 	l->l_addr->u_pcb.pcb_fpcpu = NULL;
 	ci->ci_fpcurlwp = NULL;
 
-	FPCPU_UNLOCK(&l->l_addr->u_pcb, s);
+	FPCPU_UNLOCK(&l->l_addr->u_pcb);
 
  out:
 #if defined(MULTIPROCESSOR)
 	atomic_clearbits_ulong(&ci->ci_flags, CPUF_FPUSAVE);
+	splx(s);
 #endif
 	return;
 }
@@ -1749,25 +1751,32 @@ fpusave_proc(struct lwp *l, int save)
 
 	KDASSERT(l->l_addr != NULL);
 
-	FPCPU_LOCK(&l->l_addr->u_pcb, s);
+#if defined(MULTIPROCESSOR)
+	s = splhigh();		/* block IPIs for the duration */
+#endif
+	FPCPU_LOCK(&l->l_addr->u_pcb);
 
 	oci = l->l_addr->u_pcb.pcb_fpcpu;
 	if (oci == NULL) {
-		FPCPU_UNLOCK(&l->l_addr->u_pcb, s);
+		FPCPU_UNLOCK(&l->l_addr->u_pcb);
+#if defined(MULTIPROCESSOR)
+		splx(s);
+#endif
 		return;
 	}
 
 #if defined(MULTIPROCESSOR)
 	if (oci == ci) {
 		KASSERT(ci->ci_fpcurlwp == l);
-		FPCPU_UNLOCK(&l->l_addr->u_pcb, s);
+		FPCPU_UNLOCK(&l->l_addr->u_pcb);
+		splx(s);
 		fpusave_cpu(ci, save);
 		return;
 	}
 
 	KASSERT(oci->ci_fpcurlwp == l);
 	alpha_send_ipi(oci->ci_cpuid, ipi);
-	FPCPU_UNLOCK(&l->l_addr->u_pcb, s);
+	FPCPU_UNLOCK(&l->l_addr->u_pcb);
 
 	spincount = 0;
 	while (l->l_addr->u_pcb.pcb_fpcpu != NULL) {
@@ -1778,7 +1787,7 @@ fpusave_proc(struct lwp *l, int save)
 	}
 #else
 	KASSERT(ci->ci_fpcurlwp == l);
-	FPCPU_UNLOCK(&l->l_addr->u_pcb, s);
+	FPCPU_UNLOCK(&l->l_addr->u_pcb);
 	fpusave_cpu(ci, save);
 #endif /* MULTIPROCESSOR */
 }
diff --git a/sys/arch/alpha/alpha/trap.c b/sys/arch/alpha/alpha/trap.c
index 778d273fcc2f..9fdd635d64d0 100644
--- a/sys/arch/alpha/alpha/trap.c
+++ b/sys/arch/alpha/alpha/trap.c
@@ -1,4 +1,4 @@
-/* $NetBSD: trap.c,v 1.97 2005/06/01 16:09:01 drochner Exp $ */
+/* $NetBSD: trap.c,v 1.98 2005/07/28 13:57:06 thorpej Exp $ */
 
 /*-
  * Copyright (c) 2000, 2001 The NetBSD Foundation, Inc.
@@ -100,7 +100,7 @@
 
 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
 
-__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.97 2005/06/01 16:09:01 drochner Exp $");
+__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.98 2005/07/28 13:57:06 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -634,12 +634,18 @@ alpha_enable_fp(struct lwp *l, int check)
 	KDASSERT(l->l_addr->u_pcb.pcb_fpcpu == NULL);
 #endif
 
-	FPCPU_LOCK(&l->l_addr->u_pcb, s);
+#if defined(MULTIPROCESSOR)
+	s = splhigh();		/* block IPIs */
+#endif
+	FPCPU_LOCK(&l->l_addr->u_pcb);
 
 	l->l_addr->u_pcb.pcb_fpcpu = ci;
 	ci->ci_fpcurlwp = l;
 
-	FPCPU_UNLOCK(&l->l_addr->u_pcb, s);
+	FPCPU_UNLOCK(&l->l_addr->u_pcb);
+#if defined(MULTIPROCESSOR)
+	splx(s);
+#endif
 
 	/*
 	 * Instrument FP usage -- if a process had not previously
diff --git a/sys/arch/alpha/include/pcb.h b/sys/arch/alpha/include/pcb.h
index 56ca9f70cd8d..e5fd7bd76dd6 100644
--- a/sys/arch/alpha/include/pcb.h
+++ b/sys/arch/alpha/include/pcb.h
@@ -1,4 +1,4 @@
-/* $NetBSD: pcb.h,v 1.12 2003/06/29 22:28:05 fvdl Exp $ */
+/* $NetBSD: pcb.h,v 1.13 2005/07/28 13:57:06 thorpej Exp $ */
 
 /*
  * Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
@@ -64,25 +64,13 @@ struct pcb {
 	struct simplelock pcb_fpcpu_slock;	/* simple lock on fpcpu [SW] */
 };
 
-#if defined(MULTIPROCESSOR)
 /*
- * Need to block IPIs while holding the fpcpu_slock.
+ * MULTIPROCESSOR:
+ * Need to block IPIs while holding the fpcpu_slock.  That is the
+ * responsibility of the CALLER!
  */
-#define	FPCPU_LOCK(pcb, s)						\
-do {									\
-	(s) = splhigh();						\
-	simple_lock(&(pcb)->pcb_fpcpu_slock);				\
-} while (/*CONSTCOND*/0)
-
-#define	FPCPU_UNLOCK(pcb, s)						\
-do {									\
-	simple_unlock(&(pcb)->pcb_fpcpu_slock);				\
-	splx((s));							\
-} while (/*CONSTCOND*/0)
-#else
-#define	FPCPU_LOCK(pcb, s)	simple_lock(&(pcb)->pcb_fpcpu_slock)
-#define	FPCPU_UNLOCK(pcb, s)	simple_unlock(&(pcb)->pcb_fpcpu_slock)
-#endif /* MULTIPROCESSOR */
+#define	FPCPU_LOCK(pcb)		simple_lock(&(pcb)->pcb_fpcpu_slock)
+#define	FPCPU_UNLOCK(pcb)	simple_unlock(&(pcb)->pcb_fpcpu_slock)
 
 /*
  * The pcb is augmented with machine-dependent additional data for