diff --git a/cddl/lib/libtpool/tests/Makefile b/cddl/lib/libtpool/tests/Makefile
index 19e43cc1882..72a82b6afa5 100644
--- a/cddl/lib/libtpool/tests/Makefile
+++ b/cddl/lib/libtpool/tests/Makefile
@@ -1,5 +1,3 @@
-ZFSTOP= ${SRCTOP}/sys/contrib/openzfs
-
 ATF_TESTS_C+=	libtpool_test
 
 TEST_METADATA+= timeout="10"
diff --git a/cddl/lib/libzpool/Makefile b/cddl/lib/libzpool/Makefile
index 031cc27fb43..57d9fb16e7a 100644
--- a/cddl/lib/libzpool/Makefile
+++ b/cddl/lib/libzpool/Makefile
@@ -1,5 +1,3 @@
-ZFSTOP=	${SRCTOP}/sys/contrib/openzfs
-
 .PATH: ${ZFSTOP}/lib/libzpool
 
 # ZFS_COMMON_SRCS
diff --git a/cddl/sbin/zfs/Makefile b/cddl/sbin/zfs/Makefile
index 9a0a5198602..3b9abe4446e 100644
--- a/cddl/sbin/zfs/Makefile
+++ b/cddl/sbin/zfs/Makefile
@@ -1,5 +1,3 @@
-ZFSTOP=	${SRCTOP}/sys/contrib/openzfs
-
 .PATH: ${ZFSTOP}/cmd/zfs
 .PATH: ${ZFSTOP}/man/man7
 .PATH: ${ZFSTOP}/man/man8
diff --git a/cddl/sbin/zpool/Makefile b/cddl/sbin/zpool/Makefile
index ab7b852b4d9..be498d73001 100644
--- a/cddl/sbin/zpool/Makefile
+++ b/cddl/sbin/zpool/Makefile
@@ -1,5 +1,3 @@
-ZFSTOP=	${SRCTOP}/sys/contrib/openzfs
-
 .PATH: ${ZFSTOP}/man/man4
 .PATH: ${ZFSTOP}/man/man5
 .PATH: ${ZFSTOP}/man/man7
diff --git a/cddl/share/zfs/compatibility.d/Makefile b/cddl/share/zfs/compatibility.d/Makefile
index 6d3663081ae..4bc8da77416 100644
--- a/cddl/share/zfs/compatibility.d/Makefile
+++ b/cddl/share/zfs/compatibility.d/Makefile
@@ -1,5 +1,3 @@
-ZFSTOP= ${SRCTOP}/sys/contrib/openzfs
-
 .PATH: ${ZFSTOP}/cmd/zpool/compatibility.d
 
 PACKAGE=	zfs
diff --git a/cddl/usr.bin/zinject/Makefile b/cddl/usr.bin/zinject/Makefile
index fd8437ed3f2..2305c36ccba 100644
--- a/cddl/usr.bin/zinject/Makefile
+++ b/cddl/usr.bin/zinject/Makefile
@@ -1,5 +1,3 @@
-ZFSTOP=	${SRCTOP}/sys/contrib/openzfs
-
 .PATH: ${ZFSTOP}/cmd/zinject
 .PATH: ${ZFSTOP}/man/man8
 
diff --git a/cddl/usr.bin/zstream/Makefile b/cddl/usr.bin/zstream/Makefile
index 7b753f79c4d..09f4b81025c 100644
--- a/cddl/usr.bin/zstream/Makefile
+++ b/cddl/usr.bin/zstream/Makefile
@@ -1,5 +1,3 @@
-ZFSTOP=	${SRCTOP}/sys/contrib/openzfs
-
 .PATH: ${ZFSTOP}/cmd/zstream
 .PATH: ${ZFSTOP}/man/man8
 
diff --git a/cddl/usr.bin/ztest/Makefile b/cddl/usr.bin/ztest/Makefile
index ef4bd561b41..755764493dd 100644
--- a/cddl/usr.bin/ztest/Makefile
+++ b/cddl/usr.bin/ztest/Makefile
@@ -1,7 +1,5 @@
 .include <src.opts.mk>
 
-ZFSTOP=	${SRCTOP}/sys/contrib/openzfs
-
 .PATH: ${ZFSTOP}/cmd
 .PATH: ${ZFSTOP}/man/man1
 
diff --git a/cddl/usr.libexec/zfs_prepare_disk/Makefile b/cddl/usr.libexec/zfs_prepare_disk/Makefile
index 0d3f9b56b28..1a261c5684b 100644
--- a/cddl/usr.libexec/zfs_prepare_disk/Makefile
+++ b/cddl/usr.libexec/zfs_prepare_disk/Makefile
@@ -1,5 +1,3 @@
-ZFSTOP= ${SRCTOP}/sys/contrib/openzfs
-
 .PATH: ${ZFSTOP}/scripts
 
 PACKAGE=	zfs
diff --git a/cddl/usr.libexec/zpool_influxdb/Makefile b/cddl/usr.libexec/zpool_influxdb/Makefile
index f91ce1a7a21..53779443573 100644
--- a/cddl/usr.libexec/zpool_influxdb/Makefile
+++ b/cddl/usr.libexec/zpool_influxdb/Makefile
@@ -1,5 +1,3 @@
-ZFSTOP=	${SRCTOP}/sys/contrib/openzfs
-
 .PATH: ${ZFSTOP}/cmd/zpool_influxdb
 .PATH: ${ZFSTOP}/man/man8
 
diff --git a/cddl/usr.sbin/zdb/Makefile b/cddl/usr.sbin/zdb/Makefile
index f8f7eea6050..2e8f8860364 100644
--- a/cddl/usr.sbin/zdb/Makefile
+++ b/cddl/usr.sbin/zdb/Makefile
@@ -1,5 +1,3 @@
-ZFSTOP=	${SRCTOP}/sys/contrib/openzfs
-
 .PATH: ${ZFSTOP}/cmd/zdb
 .PATH: ${ZFSTOP}/man/man8
 
diff --git a/cddl/usr.sbin/zhack/Makefile b/cddl/usr.sbin/zhack/Makefile
index 2b981919e17..0d83856eb08 100644
--- a/cddl/usr.sbin/zhack/Makefile
+++ b/cddl/usr.sbin/zhack/Makefile
@@ -1,5 +1,3 @@
-ZFSTOP= ${SRCTOP}/sys/contrib/openzfs
-
 .PATH: ${ZFSTOP}/cmd
 .PATH: ${ZFSTOP}/man/man1
 
diff --git a/share/mk/src.sys.mk b/share/mk/src.sys.mk
index ec035fb71e5..6d6523f2475 100644
--- a/share/mk/src.sys.mk
+++ b/share/mk/src.sys.mk
@@ -48,6 +48,9 @@ CFLAGS+=	-fmacro-prefix-map=${SRCTOP}=/usr/src -fdebug-prefix-map=${SRCTOP}=/usr
 
 DEFAULTWARNS?=	6
 
+# ZFS source directory
+ZFSTOP?=	${SRCTOP}/sys/contrib/openzfs
+
 # tempting, but bsd.compiler.mk causes problems this early
 # probably need to remove dependence on bsd.own.mk 
 #.include "src.opts.mk"