diff --git a/sys/amd64/amd64/apic_vector.S b/sys/amd64/amd64/apic_vector.S
index 09e1b87d88df..7acd37cc5b17 100644
--- a/sys/amd64/amd64/apic_vector.S
+++ b/sys/amd64/amd64/apic_vector.S
@@ -1,6 +1,6 @@
 /*
  *	from: vector.s, 386BSD 0.1 unknown origin
- *	$Id: apic_vector.s,v 1.39 1999/06/01 18:20:11 jlemon Exp $
+ *	$Id: apic_vector.s,v 1.40 1999/06/16 03:53:52 tegge Exp $
  */
 
 
@@ -398,6 +398,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	MASK_IRQ(irq_num) ;						\
 	EOI_IRQ(irq_num) ;						\
 	AVCPL_LOCK ;				/* MP-safe */		\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 	lock ;								\
@@ -409,6 +410,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	ALIGN_TEXT ;							\
 2: ;						/* masked by cpl|cml */	\
 	APIC_ITRACE(apic_itrace_masked, irq_num, APIC_ITRACE_MASKED) ;	\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 	DELOCK ;		/* XXX this is going away... */		\
@@ -418,6 +420,7 @@ __CONCAT(Xresume,irq_num): ;						\
 3: ; 			/* other cpu has isr lock */			\
 	APIC_ITRACE(apic_itrace_noisrlock, irq_num, APIC_ITRACE_NOISRLOCK) ;\
 	AVCPL_LOCK ;				/* MP-safe */		\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	testl	$IRQ_BIT(irq_num), _cpl ;				\
 	jne	4f ;				/* this INT masked */	\
@@ -485,6 +488,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	pushl	%eax ;							\
 	orl	_intr_mask + (irq_num) * 4, %eax ;			\
 	movl	%eax, _cpl ;						\
+	lock ;								\
 	andl	$~IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 ;									\
@@ -508,6 +512,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	MASK_IRQ(irq_num) ;						\
 	EOI_IRQ(irq_num) ;						\
 	AVCPL_LOCK ;				/* MP-safe */		\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 	lock ;								\
@@ -518,6 +523,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	ALIGN_TEXT ;							\
 2: ;				/* masked by cpl, leave iactive set */	\
 	APIC_ITRACE(apic_itrace_masked, irq_num, APIC_ITRACE_MASKED) ;	\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 	ISR_RELLOCK ;		/* XXX this is going away... */		\
@@ -527,6 +533,7 @@ __CONCAT(Xresume,irq_num): ;						\
 3: ; 			/* other cpu has isr lock */			\
 	APIC_ITRACE(apic_itrace_noisrlock, irq_num, APIC_ITRACE_NOISRLOCK) ;\
 	AVCPL_LOCK ;				/* MP-safe */		\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	testl	$IRQ_BIT(irq_num), _cpl ;				\
 	jne	4f ;				/* this INT masked */	\
@@ -698,6 +705,7 @@ _Xcpuast:
 	movl	_cpl, %eax
 #endif
 	pushl	%eax
+	lock
 	orl	$SWI_AST_PENDING, _ipending
 	AVCPL_UNLOCK
 	lock
diff --git a/sys/amd64/amd64/cpu_switch.S b/sys/amd64/amd64/cpu_switch.S
index 757861889b8c..428b0ae2d573 100644
--- a/sys/amd64/amd64/cpu_switch.S
+++ b/sys/amd64/amd64/cpu_switch.S
@@ -33,7 +33,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: swtch.s,v 1.81 1999/05/12 21:38:45 luoqi Exp $
+ *	$Id: swtch.s,v 1.82 1999/06/01 18:19:45 jlemon Exp $
  */
 
 #include "npx.h"
@@ -311,7 +311,7 @@ _idle:
 	 * XXX: we had damn well better be sure we had it before doing this!
 	 */
 	CPL_LOCK			/* XXX */
-	andl	$~SWI_AST_MASK, _ipending 			/* XXX */
+	MPLOCKED andl	$~SWI_AST_MASK, _ipending 			/* XXX */
 	movl	$0, _cpl	/* XXX Allow ASTs on other CPU */
 	CPL_UNLOCK			/* XXX */
 	movl	$FREE_LOCK, %eax
diff --git a/sys/amd64/amd64/swtch.s b/sys/amd64/amd64/swtch.s
index 757861889b8c..428b0ae2d573 100644
--- a/sys/amd64/amd64/swtch.s
+++ b/sys/amd64/amd64/swtch.s
@@ -33,7 +33,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: swtch.s,v 1.81 1999/05/12 21:38:45 luoqi Exp $
+ *	$Id: swtch.s,v 1.82 1999/06/01 18:19:45 jlemon Exp $
  */
 
 #include "npx.h"
@@ -311,7 +311,7 @@ _idle:
 	 * XXX: we had damn well better be sure we had it before doing this!
 	 */
 	CPL_LOCK			/* XXX */
-	andl	$~SWI_AST_MASK, _ipending 			/* XXX */
+	MPLOCKED andl	$~SWI_AST_MASK, _ipending 			/* XXX */
 	movl	$0, _cpl	/* XXX Allow ASTs on other CPU */
 	CPL_UNLOCK			/* XXX */
 	movl	$FREE_LOCK, %eax
diff --git a/sys/i386/i386/apic_vector.s b/sys/i386/i386/apic_vector.s
index 09e1b87d88df..7acd37cc5b17 100644
--- a/sys/i386/i386/apic_vector.s
+++ b/sys/i386/i386/apic_vector.s
@@ -1,6 +1,6 @@
 /*
  *	from: vector.s, 386BSD 0.1 unknown origin
- *	$Id: apic_vector.s,v 1.39 1999/06/01 18:20:11 jlemon Exp $
+ *	$Id: apic_vector.s,v 1.40 1999/06/16 03:53:52 tegge Exp $
  */
 
 
@@ -398,6 +398,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	MASK_IRQ(irq_num) ;						\
 	EOI_IRQ(irq_num) ;						\
 	AVCPL_LOCK ;				/* MP-safe */		\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 	lock ;								\
@@ -409,6 +410,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	ALIGN_TEXT ;							\
 2: ;						/* masked by cpl|cml */	\
 	APIC_ITRACE(apic_itrace_masked, irq_num, APIC_ITRACE_MASKED) ;	\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 	DELOCK ;		/* XXX this is going away... */		\
@@ -418,6 +420,7 @@ __CONCAT(Xresume,irq_num): ;						\
 3: ; 			/* other cpu has isr lock */			\
 	APIC_ITRACE(apic_itrace_noisrlock, irq_num, APIC_ITRACE_NOISRLOCK) ;\
 	AVCPL_LOCK ;				/* MP-safe */		\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	testl	$IRQ_BIT(irq_num), _cpl ;				\
 	jne	4f ;				/* this INT masked */	\
@@ -485,6 +488,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	pushl	%eax ;							\
 	orl	_intr_mask + (irq_num) * 4, %eax ;			\
 	movl	%eax, _cpl ;						\
+	lock ;								\
 	andl	$~IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 ;									\
@@ -508,6 +512,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	MASK_IRQ(irq_num) ;						\
 	EOI_IRQ(irq_num) ;						\
 	AVCPL_LOCK ;				/* MP-safe */		\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 	lock ;								\
@@ -518,6 +523,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	ALIGN_TEXT ;							\
 2: ;				/* masked by cpl, leave iactive set */	\
 	APIC_ITRACE(apic_itrace_masked, irq_num, APIC_ITRACE_MASKED) ;	\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 	ISR_RELLOCK ;		/* XXX this is going away... */		\
@@ -527,6 +533,7 @@ __CONCAT(Xresume,irq_num): ;						\
 3: ; 			/* other cpu has isr lock */			\
 	APIC_ITRACE(apic_itrace_noisrlock, irq_num, APIC_ITRACE_NOISRLOCK) ;\
 	AVCPL_LOCK ;				/* MP-safe */		\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	testl	$IRQ_BIT(irq_num), _cpl ;				\
 	jne	4f ;				/* this INT masked */	\
@@ -698,6 +705,7 @@ _Xcpuast:
 	movl	_cpl, %eax
 #endif
 	pushl	%eax
+	lock
 	orl	$SWI_AST_PENDING, _ipending
 	AVCPL_UNLOCK
 	lock
diff --git a/sys/i386/i386/swtch.s b/sys/i386/i386/swtch.s
index 757861889b8c..428b0ae2d573 100644
--- a/sys/i386/i386/swtch.s
+++ b/sys/i386/i386/swtch.s
@@ -33,7 +33,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: swtch.s,v 1.81 1999/05/12 21:38:45 luoqi Exp $
+ *	$Id: swtch.s,v 1.82 1999/06/01 18:19:45 jlemon Exp $
  */
 
 #include "npx.h"
@@ -311,7 +311,7 @@ _idle:
 	 * XXX: we had damn well better be sure we had it before doing this!
 	 */
 	CPL_LOCK			/* XXX */
-	andl	$~SWI_AST_MASK, _ipending 			/* XXX */
+	MPLOCKED andl	$~SWI_AST_MASK, _ipending 			/* XXX */
 	movl	$0, _cpl	/* XXX Allow ASTs on other CPU */
 	CPL_UNLOCK			/* XXX */
 	movl	$FREE_LOCK, %eax
diff --git a/sys/i386/isa/apic_ipl.s b/sys/i386/isa/apic_ipl.s
index 51ba09511fef..9ed8de08a97f 100644
--- a/sys/i386/isa/apic_ipl.s
+++ b/sys/i386/isa/apic_ipl.s
@@ -22,7 +22,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: apic_ipl.s,v 1.22 1998/09/06 22:41:41 tegge Exp $
+ *	$Id: apic_ipl.s,v 1.23 1999/04/10 19:22:17 tegge Exp $
  */
 
 
@@ -116,6 +116,7 @@ splz_next:
 	ALIGN_TEXT
 splz_unpend:
 	bsfl	%ecx,%ecx
+	lock
 	btrl	%ecx,_ipending
 	jnc	splz_next
 	cmpl	$NHWI,%ecx
diff --git a/sys/i386/isa/apic_vector.s b/sys/i386/isa/apic_vector.s
index 09e1b87d88df..7acd37cc5b17 100644
--- a/sys/i386/isa/apic_vector.s
+++ b/sys/i386/isa/apic_vector.s
@@ -1,6 +1,6 @@
 /*
  *	from: vector.s, 386BSD 0.1 unknown origin
- *	$Id: apic_vector.s,v 1.39 1999/06/01 18:20:11 jlemon Exp $
+ *	$Id: apic_vector.s,v 1.40 1999/06/16 03:53:52 tegge Exp $
  */
 
 
@@ -398,6 +398,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	MASK_IRQ(irq_num) ;						\
 	EOI_IRQ(irq_num) ;						\
 	AVCPL_LOCK ;				/* MP-safe */		\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 	lock ;								\
@@ -409,6 +410,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	ALIGN_TEXT ;							\
 2: ;						/* masked by cpl|cml */	\
 	APIC_ITRACE(apic_itrace_masked, irq_num, APIC_ITRACE_MASKED) ;	\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 	DELOCK ;		/* XXX this is going away... */		\
@@ -418,6 +420,7 @@ __CONCAT(Xresume,irq_num): ;						\
 3: ; 			/* other cpu has isr lock */			\
 	APIC_ITRACE(apic_itrace_noisrlock, irq_num, APIC_ITRACE_NOISRLOCK) ;\
 	AVCPL_LOCK ;				/* MP-safe */		\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	testl	$IRQ_BIT(irq_num), _cpl ;				\
 	jne	4f ;				/* this INT masked */	\
@@ -485,6 +488,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	pushl	%eax ;							\
 	orl	_intr_mask + (irq_num) * 4, %eax ;			\
 	movl	%eax, _cpl ;						\
+	lock ;								\
 	andl	$~IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 ;									\
@@ -508,6 +512,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	MASK_IRQ(irq_num) ;						\
 	EOI_IRQ(irq_num) ;						\
 	AVCPL_LOCK ;				/* MP-safe */		\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 	lock ;								\
@@ -518,6 +523,7 @@ __CONCAT(Xresume,irq_num): ;						\
 	ALIGN_TEXT ;							\
 2: ;				/* masked by cpl, leave iactive set */	\
 	APIC_ITRACE(apic_itrace_masked, irq_num, APIC_ITRACE_MASKED) ;	\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	AVCPL_UNLOCK ;							\
 	ISR_RELLOCK ;		/* XXX this is going away... */		\
@@ -527,6 +533,7 @@ __CONCAT(Xresume,irq_num): ;						\
 3: ; 			/* other cpu has isr lock */			\
 	APIC_ITRACE(apic_itrace_noisrlock, irq_num, APIC_ITRACE_NOISRLOCK) ;\
 	AVCPL_LOCK ;				/* MP-safe */		\
+	lock ;								\
 	orl	$IRQ_BIT(irq_num), _ipending ;				\
 	testl	$IRQ_BIT(irq_num), _cpl ;				\
 	jne	4f ;				/* this INT masked */	\
@@ -698,6 +705,7 @@ _Xcpuast:
 	movl	_cpl, %eax
 #endif
 	pushl	%eax
+	lock
 	orl	$SWI_AST_PENDING, _ipending
 	AVCPL_UNLOCK
 	lock
diff --git a/sys/i386/isa/ipl.s b/sys/i386/isa/ipl.s
index 66f31cf672d1..51e8329cf63e 100644
--- a/sys/i386/isa/ipl.s
+++ b/sys/i386/isa/ipl.s
@@ -36,7 +36,7 @@
  *
  *	@(#)ipl.s
  *
- *	$Id: ipl.s,v 1.27 1999/05/06 09:44:54 bde Exp $
+ *	$Id: ipl.s,v 1.28 1999/06/01 18:20:15 jlemon Exp $
  */
 
 
@@ -236,6 +236,7 @@ doreti_unpend:
 	TEST_CIL
 	/* we enter with cpl locked */
 	bsfl	%ecx, %ecx		/* slow, but not worth optimizing */
+	lock
 	btrl	%ecx, _ipending
 	jnc	doreti_next2		/* some intr cleared memory copy */
 	cmpl	$NHWI, %ecx
@@ -377,7 +378,7 @@ swi_ast_phantom:
 	 */
 	cli
 	ICPL_LOCK
-	orl $SWI_AST_PENDING, _ipending
+	MPLOCKED orl $SWI_AST_PENDING, _ipending
 	/* cpl is unlocked in doreti_exit */
 	subl	%eax,%eax
 #ifdef CPL_AND_CML