diff --git a/sys/arm64/arm64/nexus.c b/sys/arm64/arm64/nexus.c
--- a/sys/arm64/arm64/nexus.c
+++ b/sys/arm64/arm64/nexus.c
@@ -462,7 +462,8 @@
     struct resource_map_request *argsp, struct resource_map *map)
 {
 	struct resource_map_request args;
-	rman_res_t end, length, start;
+	rman_res_t length, start;
+	int error;
 
 	/* Resources must be active to be mapped. */
 	if ((rman_get_flags(r) & RF_ACTIVE) == 0)
@@ -478,18 +479,9 @@
 	}
 
 	resource_init_map_request(&args);
-	if (argsp != NULL)
-		bcopy(argsp, &args, imin(argsp->size, args.size));
-	start = rman_get_start(r) + args.offset;
-	if (args.length == 0)
-		length = rman_get_size(r);
-	else
-		length = args.length;
-	end = start + length - 1;
-	if (start > rman_get_end(r) || start < rman_get_start(r))
-		return (EINVAL);
-	if (end > rman_get_end(r) || end < start)
-		return (EINVAL);
+	error = resource_validate_map_request(r, argsp, &args, &start, &length);
+	if (error)
+		return (error);
 
 	map->r_vaddr = pmap_mapdev_attr(start, length, args.memattr);
 	map->r_bustag = &memmap_bus;
diff --git a/sys/powerpc/powerpc/nexus.c b/sys/powerpc/powerpc/nexus.c
--- a/sys/powerpc/powerpc/nexus.c
+++ b/sys/powerpc/powerpc/nexus.c
@@ -353,9 +353,9 @@
 nexus_map_resource(device_t bus, device_t child, int type, struct resource *r,
     struct resource_map_request *argsp, struct resource_map *map)
 {
-
 	struct resource_map_request args;
-	rman_res_t end, length, start;
+	rman_res_t length, start;
+	int error;
 
 	/* Resources must be active to be mapped. */
 	if (!(rman_get_flags(r) & RF_ACTIVE))
@@ -371,21 +371,9 @@
 	}
 
 	resource_init_map_request(&args);
-	if (argsp != NULL)
-		bcopy(argsp, &args, imin(argsp->size, args.size));
-
-	start = rman_get_start(r) + args.offset;
-	if (args.length == 0)
-		length = rman_get_size(r);
-	else
-		length = args.length;
-
-	end = start + length - 1;
-	if (start > rman_get_end(r) || start < rman_get_start(r))
-		return (EINVAL);
-
-	if (end > rman_get_end(r) || end < start)
-		return (EINVAL);
+	error = resource_validate_map_request(r, argsp, &args, &start, &length);
+	if (error)
+		return (error);
 
 	/*
 	 * If this is a memory resource, map it into the kernel.
diff --git a/sys/riscv/riscv/nexus.c b/sys/riscv/riscv/nexus.c
--- a/sys/riscv/riscv/nexus.c
+++ b/sys/riscv/riscv/nexus.c
@@ -424,7 +424,8 @@
     struct resource_map_request *argsp, struct resource_map *map)
 {
 	struct resource_map_request args;
-	rman_res_t end, length, start;
+	rman_res_t length, start;
+	int error;
 
 	/* Resources must be active to be mapped. */
 	if ((rman_get_flags(r) & RF_ACTIVE) == 0)
@@ -440,18 +441,9 @@
 	}
 
 	resource_init_map_request(&args);
-	if (argsp != NULL)
-		bcopy(argsp, &args, imin(argsp->size, args.size));
-	start = rman_get_start(r) + args.offset;
-	if (args.length == 0)
-		length = rman_get_size(r);
-	else
-		length = args.length;
-	end = start + length - 1;
-	if (start > rman_get_end(r) || start < rman_get_start(r))
-		return (EINVAL);
-	if (end > rman_get_end(r) || end < start)
-		return (EINVAL);
+	error = resource_validate_map_request(r, argsp, &args, &start, &length);
+	if (error)
+		return (error);
 
 	map->r_vaddr = pmap_mapdev(start, length);
 	map->r_bustag = &memmap_bus;
diff --git a/sys/x86/x86/nexus.c b/sys/x86/x86/nexus.c
--- a/sys/x86/x86/nexus.c
+++ b/sys/x86/x86/nexus.c
@@ -458,7 +458,8 @@
     struct resource_map_request *argsp, struct resource_map *map)
 {
 	struct resource_map_request args;
-	rman_res_t end, length, start;
+	rman_res_t length, start;
+	int error;
 
 	/* Resources must be active to be mapped. */
 	if (!(rman_get_flags(r) & RF_ACTIVE))
@@ -474,18 +475,9 @@
 	}
 
 	resource_init_map_request(&args);
-	if (argsp != NULL)
-		bcopy(argsp, &args, imin(argsp->size, args.size));
-	start = rman_get_start(r) + args.offset;
-	if (args.length == 0)
-		length = rman_get_size(r);
-	else
-		length = args.length;
-	end = start + length - 1;
-	if (start > rman_get_end(r) || start < rman_get_start(r))
-		return (EINVAL);
-	if (end > rman_get_end(r) || end < start)
-		return (EINVAL);
+	error = resource_validate_map_request(r, argsp, &args, &start, &length);
+	if (error)
+		return (error);
 
 	/*
 	 * If this is a memory resource, map it into the kernel.