Index: kern/subr_smp.c
===================================================================
--- kern/subr_smp.c	(revision 183527)
+++ kern/subr_smp.c	(working copy)
@@ -285,7 +285,12 @@
 	CTR1(KTR_SMP, "restart_cpus(%x)", map);
 
 	/* signal other cpus to restart */
+#if defined(__amd64__)
+	/* cpumask_t is 64 bit on amd64. */
+	atomic_store_rel_long(&started_cpus, map);
+#else
 	atomic_store_rel_int(&started_cpus, map);
+#endif
 
 	/* wait for each to clear its bit */
 	while ((stopped_cpus & map) != 0)
@@ -455,8 +460,8 @@
 		panic("Built bad topology at %p.  CPU count %d != %d",
 		    top, top->cg_count, mp_ncpus);
 	if (top->cg_mask != all_cpus)
-		panic("Built bad topology at %p.  CPU mask 0x%X != 0x%X",
-		    top, top->cg_mask, all_cpus);
+		panic("Built bad topology at %p.  CPU mask 0x%lX != 0x%lX",
+		    top, (unsigned long)top->cg_mask, (unsigned long)all_cpus);
 	return (top);
 }
 
@@ -496,8 +501,8 @@
 	parent->cg_children++;
 	for (; parent != NULL; parent = parent->cg_parent) {
 		if ((parent->cg_mask & child->cg_mask) != 0)
-			panic("Duplicate children in %p.  mask 0x%X child 0x%X",
-			    parent, parent->cg_mask, child->cg_mask);
+			panic("Duplicate children in %p.  mask 0x%lX child 0x%lX",
+			    parent, (unsigned long)parent->cg_mask, (unsigned long)child->cg_mask);
 		parent->cg_mask |= child->cg_mask;
 		parent->cg_count += child->cg_count;
 	}
Index: amd64/include/smp.h
===================================================================
--- amd64/include/smp.h	(revision 183527)
+++ amd64/include/smp.h	(working copy)
@@ -61,12 +61,12 @@
 int	mp_grab_cpu_hlt(void);
 void	smp_cache_flush(void);
 void	smp_invlpg(vm_offset_t addr);
-void	smp_masked_invlpg(u_int mask, vm_offset_t addr);
+void	smp_masked_invlpg(cpumask_t mask, vm_offset_t addr);
 void	smp_invlpg_range(vm_offset_t startva, vm_offset_t endva);
-void	smp_masked_invlpg_range(u_int mask, vm_offset_t startva,
+void	smp_masked_invlpg_range(cpumask_t mask, vm_offset_t startva,
 	    vm_offset_t endva);
 void	smp_invltlb(void);
-void	smp_masked_invltlb(u_int mask);
+void	smp_masked_invltlb(cpumask_t mask);
 
 #ifdef STOP_NMI
 int	ipi_nmi_handler(void);
Index: amd64/include/_types.h
===================================================================
--- amd64/include/_types.h	(revision 183527)
+++ amd64/include/_types.h	(working copy)
@@ -61,7 +61,7 @@
  * Standard type definitions.
  */
 typedef	__int32_t	__clock_t;		/* clock()... */
-typedef	unsigned int	__cpumask_t;
+typedef	unsigned long	__cpumask_t;
 typedef	__int64_t	__critical_t;
 typedef	double		__double_t;
 typedef	float		__float_t;
Index: amd64/include/pmap.h
===================================================================
--- amd64/include/pmap.h	(revision 183527)
+++ amd64/include/pmap.h	(working copy)
@@ -247,8 +247,7 @@
 	struct mtx		pm_mtx;
 	pml4_entry_t		*pm_pml4;	/* KVA of level 4 page table */
 	TAILQ_HEAD(,pv_chunk)	pm_pvchunk;	/* list of mappings in pmap */
-	u_int			pm_active;	/* active on cpus */
-	/* spare u_int here due to padding */
+	cpumask_t		pm_active;	/* active on cpus */
 	struct pmap_statistics	pm_stats;	/* pmap statistics */
 	vm_page_t		pm_root;	/* spare page table pages */
 };
Index: amd64/amd64/vm_machdep.c
===================================================================
--- amd64/amd64/vm_machdep.c	(revision 183527)
+++ amd64/amd64/vm_machdep.c	(working copy)
@@ -411,7 +411,8 @@
 cpu_reset()
 {
 #ifdef SMP
-	u_int cnt, map;
+	u_int cnt;
+	cpumask_t map;
 
 	if (smp_active) {
 		map = PCPU_GET(other_cpus) & ~stopped_cpus;
@@ -427,7 +428,7 @@
 			printf("cpu_reset: Restarting BSP\n");
 
 			/* Restart CPU #0. */
-			atomic_store_rel_int(&started_cpus, 1 << 0);
+			atomic_store_rel_long(&started_cpus, 1 << 0);
 
 			cnt = 0;
 			while (cpu_reset_proxy_active == 0 && cnt < 10000000)
Index: amd64/amd64/pmap.c
===================================================================
--- amd64/amd64/pmap.c	(revision 183527)
+++ amd64/amd64/pmap.c	(working copy)
@@ -858,8 +858,7 @@
 void
 pmap_invalidate_page(pmap_t pmap, vm_offset_t va)
 {
-	u_int cpumask;
-	u_int other_cpus;
+	cpumask_t cpumask, other_cpus;
 
 	sched_pin();
 	if (pmap == kernel_pmap || pmap->pm_active == all_cpus) {
@@ -879,8 +878,7 @@
 void
 pmap_invalidate_range(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
 {
-	u_int cpumask;
-	u_int other_cpus;
+	cpumask_t cpumask, other_cpus;
 	vm_offset_t addr;
 
 	sched_pin();
@@ -904,8 +902,7 @@
 void
 pmap_invalidate_all(pmap_t pmap)
 {
-	u_int cpumask;
-	u_int other_cpus;
+	cpumask_t cpumask, other_cpus;
 
 	sched_pin();
 	if (pmap == kernel_pmap || pmap->pm_active == all_cpus) {
@@ -4739,8 +4736,8 @@
 	oldpmap = PCPU_GET(curpmap);
 #ifdef SMP
 if (oldpmap)	/* XXX FIXME */
-	atomic_clear_int(&oldpmap->pm_active, PCPU_GET(cpumask));
-	atomic_set_int(&pmap->pm_active, PCPU_GET(cpumask));
+	atomic_clear_long(&oldpmap->pm_active, PCPU_GET(cpumask));
+	atomic_set_long(&pmap->pm_active, PCPU_GET(cpumask));
 #else
 if (oldpmap)	/* XXX FIXME */
 	oldpmap->pm_active &= ~PCPU_GET(cpumask);
Index: amd64/amd64/mp_machdep.c
===================================================================
--- amd64/amd64/mp_machdep.c	(revision 183527)
+++ amd64/amd64/mp_machdep.c	(working copy)
@@ -853,12 +853,12 @@
 }
 
 static void
-smp_targeted_tlb_shootdown(u_int mask, u_int vector, vm_offset_t addr1, vm_offset_t addr2)
+smp_targeted_tlb_shootdown(cpumask_t mask, u_int vector, vm_offset_t addr1, vm_offset_t addr2)
 {
 	int ncpu, othercpus;
 
 	othercpus = mp_ncpus - 1;
-	if (mask == (u_int)-1) {
+	if (mask == (cpumask_t)-1) {
 		ncpu = othercpus;
 		if (ncpu < 1)
 			return;
@@ -883,7 +883,7 @@
 	smp_tlb_addr1 = addr1;
 	smp_tlb_addr2 = addr2;
 	atomic_store_rel_int(&smp_tlb_wait, 0);
-	if (mask == (u_int)-1)
+	if (mask == (cpumask_t)-1)
 		ipi_all_but_self(vector);
 	else
 		ipi_selected(mask, vector);
@@ -927,7 +927,7 @@
 }
 
 void
-smp_masked_invltlb(u_int mask)
+smp_masked_invltlb(cpumask_t mask)
 {
 
 	if (smp_started) {
@@ -936,7 +936,7 @@
 }
 
 void
-smp_masked_invlpg(u_int mask, vm_offset_t addr)
+smp_masked_invlpg(cpumask_t mask, vm_offset_t addr)
 {
 
 	if (smp_started) {
@@ -945,7 +945,7 @@
 }
 
 void
-smp_masked_invlpg_range(u_int mask, vm_offset_t addr1, vm_offset_t addr2)
+smp_masked_invlpg_range(cpumask_t mask, vm_offset_t addr1, vm_offset_t addr2)
 {
 
 	if (smp_started) {
@@ -1045,7 +1045,7 @@
 	
 	CTR2(KTR_SMP, "%s: cpus: %x nmi", __func__, cpus);
 
-	atomic_set_int(&ipi_nmi_pending, cpus);
+	atomic_set_long(&ipi_nmi_pending, cpus);
 
 	while ((cpu = ffs(cpus)) != 0) {
 		cpu--;
@@ -1065,12 +1065,12 @@
 int
 ipi_nmi_handler(void)
 {
-	int cpumask = PCPU_GET(cpumask);
+	cpumask_t cpumask = PCPU_GET(cpumask);
 
 	if (!(ipi_nmi_pending & cpumask))
 		return 1;
 
-	atomic_clear_int(&ipi_nmi_pending, cpumask);
+	atomic_clear_long(&ipi_nmi_pending, cpumask);
 	cpustop_handler();
 	return 0;
 }
@@ -1085,19 +1085,19 @@
 cpustop_handler(void)
 {
 	int cpu = PCPU_GET(cpuid);
-	int cpumask = PCPU_GET(cpumask);
+	cpumask_t cpumask = PCPU_GET(cpumask);
 
 	savectx(&stoppcbs[cpu]);
 
 	/* Indicate that we are stopped */
-	atomic_set_int(&stopped_cpus, cpumask);
+	atomic_set_long(&stopped_cpus, cpumask);
 
 	/* Wait for restart */
 	while (!(started_cpus & cpumask))
 	    ia32_pause();
 
-	atomic_clear_int(&started_cpus, cpumask);
-	atomic_clear_int(&stopped_cpus, cpumask);
+	atomic_clear_long(&started_cpus, cpumask);
+	atomic_clear_long(&stopped_cpus, cpumask);
 
 	if (cpu == 0 && cpustop_restartfunc != NULL) {
 		cpustop_restartfunc();
@@ -1245,7 +1245,7 @@
 int
 mp_grab_cpu_hlt(void)
 {
-	u_int mask = PCPU_GET(cpumask);
+	cpumask_t mask = PCPU_GET(cpumask);
 #ifdef MP_WATCHDOG
 	u_int cpuid = PCPU_GET(cpuid);
 #endif