Index: sys/kern/makesyscalls.sh
===================================================================
--- sys/kern/makesyscalls.sh
+++ sys/kern/makesyscalls.sh
@@ -254,13 +254,6 @@
 		print > systraceret
 		next
 	}
-	syscall != $1 {
-		printf "%s: line %d: syscall number out of sync at %d\n",
-		    infile, NR, syscall
-		printf "line is:\n"
-		print
-		exit 1
-	}
 	# Returns true if the type "name" is the first flag in the type field
 	function type(name, flags, n) {
 		n = split($3, flags, /\|/)
@@ -274,6 +267,26 @@
 				return 1
 		return 0
 	}
+	{
+		n = split($1, syscall_range, /-/)
+		if (n < 1 || n > 2) {
+			printf "%s: line %d: invalid syscall number or range %s\n",
+			    infile, NR, $1
+			exit 1
+		}
+		if (n == 2 && !type("UNIMPL")) {
+			printf "%s: line %d: range permitted only with UNIMPL\n",
+			    infile, NR
+			exit 1
+		}
+	}
+	syscall != syscall_range[1] {
+		printf "%s: line %d: syscall number out of sync at %d\n",
+		    infile, NR, syscall
+		printf "line is:\n"
+		print
+		exit 1
+	}
 	function align_sysent_comment(column) {
 		printf("\t") > sysent
 		column = column + 8 - column % 8
@@ -614,11 +627,14 @@
 		next
 	}
 	type("UNIMPL") {
-		printf("\t{ 0, (sy_call_t *)nosys, AUE_NULL, NULL, 0, 0, 0, SY_THR_ABSENT },\t\t\t/* %d = %s */\n",
-		    syscall, comment) > sysent
-		printf("\t\"#%d\",\t\t\t/* %d = %s */\n",
-		    syscall, syscall, comment) > sysnames
-		syscall++
+		while (syscall == syscall_range[1] ||
+		    syscall <= syscall_range[2]) {
+			printf("\t{ 0, (sy_call_t *)nosys, AUE_NULL, NULL, 0, 0, 0, SY_THR_ABSENT },\t\t\t/* %d = %s */\n",
+			    syscall, comment) > sysent
+			printf("\t\"#%d\",\t\t\t/* %d = %s */\n",
+			    syscall, syscall, comment) > sysnames
+			syscall++
+		}
 		next
 	}
 	{