diff --git a/sys/mips/include/param.h b/sys/mips/include/param.h
index 7eae10aa5c8..98be25a981d 100644
--- a/sys/mips/include/param.h
+++ b/sys/mips/include/param.h
@@ -103,9 +103,14 @@
 #define	PAGE_SHIFT	12		/* LOG2(PAGE_SIZE) */
 #define	PAGE_SIZE	(1<<PAGE_SHIFT) /* bytes/page */
 #define	PAGE_MASK	(PAGE_SIZE-1)
+
 #define	NPTEPG		(PAGE_SIZE/(sizeof (pt_entry_t)))
 #define	NPDEPG		(PAGE_SIZE/(sizeof (pd_entry_t)))
 
+#define	SEGSHIFT	22		/* LOG2(NBSEG) */
+#define	NBSEG		(1 << SEGSHIFT)	/* bytes/segment */
+#define	SEGMASK		(NBSEG-1)	/* byte offset into segment */
+
 #define	MAXPAGESIZES	1		/* maximum number of supported page sizes */
 
 #define	BLKDEV_IOSIZE	2048		/* xxx: Why is this 1/2 page? */
diff --git a/sys/mips/include/vmparam.h b/sys/mips/include/vmparam.h
index 385d3092827..8928aef2ec3 100644
--- a/sys/mips/include/vmparam.h
+++ b/sys/mips/include/vmparam.h
@@ -51,12 +51,6 @@
  * is the top (end) of the user stack.
  */
 #define	USRTEXT		(1*PAGE_SIZE)
-/*
- * USRSTACK needs to start a little below 0x8000000 because the R8000
- * and some QED CPUs perform some virtual address checks before the
- * offset is calculated.
- */
-#define	USRSTACK	0x7ffff000	/* Start of user stack */
 
 /*
  * Virtual memory related constants, all in bytes
@@ -103,20 +97,23 @@
 #define	VM_MAX_MMAP_ADDR	VM_MAXUSER_ADDRESS
 
 #if defined(__mips_n64)
-#define	VM_MAXUSER_ADDRESS	(VM_MINUSER_ADDRESS + (NPDEPG * NPTEPG * PAGE_SIZE))
+#define	VM_MAXUSER_ADDRESS	(VM_MINUSER_ADDRESS + (NPDEPG * NBSEG))
 #define	VM_MIN_KERNEL_ADDRESS	((vm_offset_t)0xc000000000000000)
-#define	VM_MAX_KERNEL_ADDRESS	(VM_MIN_KERNEL_ADDRESS + (NPDEPG * NPTEPG * PAGE_SIZE))
+#define	VM_MAX_KERNEL_ADDRESS	(VM_MIN_KERNEL_ADDRESS + (NPDEPG * NBSEG))
 #else
 #define	VM_MAXUSER_ADDRESS	((vm_offset_t)0x80000000)
 #define	VM_MIN_KERNEL_ADDRESS	((vm_offset_t)0xC0000000)
 #define	VM_MAX_KERNEL_ADDRESS	((vm_offset_t)0xFFFFC000)
 #endif
-#if 0
-#define	KERNBASE		(VM_MIN_KERNEL_ADDRESS)
-#else
-#define	KERNBASE		((vm_offset_t)(intptr_t)(int32_t)0x80000000)
-#endif
 
+#define	KERNBASE		((vm_offset_t)(intptr_t)(int32_t)0x80000000)
+/*
+ * USRSTACK needs to start a little below 0x8000000 because the R8000
+ * and some QED CPUs perform some virtual address checks before the
+ * offset is calculated.
+ */
+#define	USRSTACK		(VM_MAXUSER_ADDRESS - PAGE_SIZE)
+ 
 /*
  * Only one memory domain.
  */
@@ -205,8 +202,4 @@
  */
 #define	VM_NFREEORDER		9
 
-#define SEGSHIFT	22		/* LOG2(NBSEG) */
-#define NBSEG		(1 << SEGSHIFT)	/* bytes/segment */
-#define SEGOFSET	(NBSEG-1)	/* byte offset into segment */
-
 #endif /* !_MACHINE_VMPARAM_H_ */
diff --git a/sys/mips/mips/pmap.c b/sys/mips/mips/pmap.c
index 9f5616e5e67..59512b3b1a7 100644
--- a/sys/mips/mips/pmap.c
+++ b/sys/mips/mips/pmap.c
@@ -133,7 +133,7 @@ __FBSDID("$FreeBSD$");
 #else
 #define	NUSERPGTBLS		(pmap_segshift(VM_MAXUSER_ADDRESS))
 #endif
-#define	mips_segtrunc(va)	((va) & ~SEGOFSET)
+#define	mips_segtrunc(va)	((va) & ~SEGMASK)
 #define	is_kernel_pmap(x)	((x) == kernel_pmap)
 
 /*
@@ -2902,14 +2902,14 @@ pmap_align_superpage(vm_object_t object, vm_ooffset_t offset,
 		return;
 	if (object != NULL && (object->flags & OBJ_COLORED) != 0)
 		offset += ptoa(object->pg_color);
-	superpage_offset = offset & SEGOFSET;
-	if (size - ((NBSEG - superpage_offset) & SEGOFSET) < NBSEG ||
-	    (*addr & SEGOFSET) == superpage_offset)
+	superpage_offset = offset & SEGMASK;
+	if (size - ((NBSEG - superpage_offset) & SEGMASK) < NBSEG ||
+	    (*addr & SEGMASK) == superpage_offset)
 		return;
-	if ((*addr & SEGOFSET) < superpage_offset)
-		*addr = (*addr & ~SEGOFSET) + superpage_offset;
+	if ((*addr & SEGMASK) < superpage_offset)
+		*addr = (*addr & ~SEGMASK) + superpage_offset;
 	else
-		*addr = ((*addr + SEGOFSET) & ~SEGOFSET) + superpage_offset;
+		*addr = ((*addr + SEGMASK) & ~SEGMASK) + superpage_offset;
 }
 
 /*