diff --git a/core/base_rules.mk b/core/base_rules.mk
index b0c9aa2..39053ee 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -69,6 +69,12 @@
 $(warning unusual tags $(LOCAL_MODULE_TAGS) on $(LOCAL_MODULE) at $(LOCAL_PATH))
 endif
 
+ifneq ($(filter $(LOCAL_MODULE_TAGS),user),)
+  ifeq ($(filter $(GRANDFATHERED_USER_MODULES),$(LOCAL_MODULE)),)
+    $(warning using user tag on $(LOCAL_MODULE) at $(LOCAL_PATH))
+  endif
+endif
+
 # Add implicit tags.
 #
 # If the local directory or one of its parents contains a MODULE_LICENSE_GPL
diff --git a/core/definitions.mk b/core/definitions.mk
index f42c2a3..6f7a05b 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1797,6 +1797,9 @@
 # when requested.
 include $(BUILD_SYSTEM)/distdir.mk
 
+# -----------------------------------------------------------------
+# The modules allowed to use a user tag
+include $(BUILD_SYSTEM)/user_tags.mk
 
 # broken:
 #	$(foreach file,$^,$(if $(findstring,.a,$(suffix $file)),-l$(file),$(file)))
diff --git a/core/user_tags.mk b/core/user_tags.mk
new file mode 100644
index 0000000..2be1825
--- /dev/null
+++ b/core/user_tags.mk
@@ -0,0 +1,491 @@
+#
+# Copyright (C) 2010 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# This is the list of modules grandfathered to use a user tag
+
+# DO NOT ADD ANY NEW MODULE TO THIS FILE
+#
+# user modules are hard to control and audit and we don't want
+# to add any new such module in the system
+
+GRANDFATHERED_USER_MODULES :=
+
+-include vendor/google/user_tags.mk
+
+GRANDFATHERED_USER_MODULES += \
+	01-test \
+	20-dns.conf \
+	95-configured \
+	aapt \
+	acp \
+	adb \
+	adbd \
+	aidl \
+	am \
+	android \
+	android-common \
+	android.policy \
+	androidprefs \
+	android.test.runner \
+	ant \
+	antlr-2.7.7 \
+	anttasks \
+	apicheck \
+	apkcheck \
+	applypatch \
+	app_process \
+	apriori \
+	archquery \
+	asm-3.1 \
+	atree \
+	audio \
+	bb2sym \
+	bb_dump \
+	bbprof \
+	bison \
+	bluetoothd \
+	bmgr \
+	bootanimation \
+	bouncycastle \
+	brcm_patchram_plus \
+	bugreport \
+	cfassembler \
+	check_stack \
+	check_trace \
+	clearsilver \
+	cmu2nuance \
+	com.android.inputmethod.pinyin.lib \
+	com.android.phone.common \
+	commons-compress-1.0 \
+	copybit.qsd8k \
+	core \
+	core-junit \
+	coverage \
+	cpufeatures \
+	create_test_dmtrace \
+	cts \
+	CtsAppSecurityTests \
+	cts-dalvik-buildutil \
+	dalvikvm \
+	dasm \
+	dbus-daemon \
+	ddmlib \
+	ddms \
+	ddmuilib \
+	debuggerd \
+	descGen \
+	dexdeps \
+	dexdump \
+	dexlist \
+	dexopt \
+	dex-tools \
+	dhcpcd \
+	dhcpcd.conf \
+	dhcpcd-run-hooks \
+	dictTest \
+	dmtracedump \
+	dnsmasq \
+	draw9patch \
+	droiddoc \
+	dumpeventlog \
+	dumpkey \
+	dump_regions \
+	dumpstate \
+	dumpsys \
+	dvz \
+	dx \
+	dx-tests \
+	easymock \
+	edify \
+	emmalib \
+	emulator \
+	emulator-arm \
+	emulator-core \
+	emulator-elff \
+	emulator-hw \
+	emulator-memcheck \
+	emulator-tcg \
+	emulator-ui \
+	etc1tool \
+	eventanalyzer \
+	exc_dump \
+	ext \
+	fastboot \
+	framework \
+	FrameworkCoreHostTests \
+	fsck_msdos \
+	fs_get_stats \
+	fw_bcm4329_apsta.bin \
+	fw_bcm4329.bin \
+	genext2fs \
+	gps.mahimahi \
+	gralloc.default \
+	gralloc.qsd8k \
+	groovy-all-1.7.0 \
+	grxmlcompile \
+	guava \
+	guavalib \
+	gzip \
+	hciattach \
+	hierarchyviewer \
+	hist_trace \
+	hosttestlib \
+	hprof-conv \
+	icudata \
+	idegen \
+	ime \
+	init \
+	input \
+	installd \
+	iptables \
+	ip-up-vpn \
+	iself \
+	isprelinked \
+	jarjar \
+	jasmin \
+	jasmin.jar \
+	javax.obex \
+	jcommon-1.0.12 \
+	jdiff \
+	jdwpspy \
+	jfreechart-1.0.9 \
+	jfreechart-1.0.9-swt \
+	jsr305 \
+	jsr305lib \
+	junit \
+	jython \
+	kcm \
+	keystore \
+	kxml2-2.3.0 \
+	layoutlib \
+	layoutlib_api \
+	layoutlib_create \
+	layoutlib_utils \
+	layoutopt \
+	liba2dp \
+	libabi \
+	libacc \
+	libandroid \
+	libandroid_runtime \
+	libandroid_servers \
+	libarity \
+	libastl \
+	libastl_host \
+	libaudio \
+	libaudioeffect_jni \
+	libaudioflinger \
+	libaudiointerface \
+	libaudiopolicy \
+	libaudiopolicybase \
+	libbinder \
+	libbluedroid \
+	libbluetooth \
+	libbluetoothd \
+	libbuiltinplugin \
+	libbundlewrapper \
+	libbz \
+	libc \
+	libcamera_client \
+	libcameraservice \
+	libcamerastub \
+	libc_common \
+	libc_nomalloc \
+	libcrypto \
+	libctest \
+	libcutils \
+	libdb \
+	libdbus \
+	libdex \
+	libdiskconfig \
+	libdl \
+	libdrm1 \
+	libdrm1_jni \
+	libdvm \
+	libebl \
+	libebl_arm \
+	libebl_sh \
+	libedify \
+	libeffects \
+	libEGL \
+	libelf \
+	libelfcopy \
+	libESR_Portable \
+	libESR_Shared \
+	libETC1 \
+	libexif \
+	libexpat \
+	libext \
+	libfdlibm \
+	libFFTEm \
+	libfst \
+	libft2 \
+	libgdbus_static \
+	libgif \
+	libGLES_android \
+	libGLESv1_CM \
+	libGLESv2 \
+	libglib_static \
+	libgui \
+	libhardware \
+	libhardware_legacy \
+	libhost \
+	libicui18n \
+	libicuuc \
+	libiprouteutil \
+	libiptc \
+	libjavacore \
+	libjnigraphics \
+	libjni_latinime \
+	libjni_pinyinime \
+	libjpeg \
+	libjs \
+	liblinenoise \
+	libloc_api-rpc \
+	liblog \
+	libm \
+	libmedia \
+	libmedia_jni \
+	libmediaplayerservice \
+	libmincrypt \
+	libminui \
+	libminzip \
+	libmtdutils \
+	libmusicbundle \
+	libnativehelper \
+	libneo_cgi \
+	libneo_cs \
+	libneo_util \
+	libnetlink \
+	libnetutils \
+	libop \
+	libOpenSLES \
+	libopensles_helper \
+	libOpenSLESUT \
+	libpcap \
+	libpixelflinger \
+	libpixelflinger_armv6 \
+	libpixelflinger_static \
+	libpng \
+	libpopt \
+	libpower \
+	librecovery_ui_htc \
+	libreference-cdma-sms \
+	libreference-ril \
+	libreverb \
+	libreverbwrapper \
+	libril \
+	librpc \
+	librtp_jni \
+	libsafe_iop \
+	libSDL \
+	libSDLmain \
+	libsensorservice \
+	libskia \
+	libskiagl \
+	libsonivox \
+	libsoundpool \
+	libspeex \
+	libsqlite \
+	libsqlite3_android \
+	libsqlite_jni \
+	libSR_AcousticModels \
+	libSR_AcousticState \
+	libSR_AudioIn \
+	libSR_Core \
+	libsrec_jni \
+	libSR_EventLog \
+	libSR_G2P \
+	libSR_Grammar \
+	libSR_Nametag \
+	libSR_Recognizer \
+	libSR_Semproc \
+	libSR_Session \
+	libSR_Vocabulary \
+	libssl \
+	libstagefright \
+	libstagefright_aacdec \
+	libstagefright_aacenc \
+	libstagefright_amrnb_common \
+	libstagefright_amrnbdec \
+	libstagefright_amrnbenc \
+	libstagefright_amrwbdec \
+	libstagefright_amrwbenc \
+	libstagefright_avc_common \
+	libstagefright_avcdec \
+	libstagefright_avcenc \
+	libstagefright_color_conversion \
+	libstagefright_enc_common \
+	libstagefright_foundation \
+	libstagefright_g711dec \
+	libstagefright_httplive \
+	libstagefrighthw \
+	libstagefright_id3 \
+	libstagefright_m4vh263dec \
+	libstagefright_m4vh263enc \
+	libstagefright_matroska \
+	libstagefright_mp3dec \
+	libstagefright_mpeg2ts \
+	libstagefright_omx \
+	libstagefright_rtsp \
+	libstagefright_vorbisdec \
+	libstagefright_vpxdec \
+	libstdc++ \
+	libstlport \
+	libstlport_static \
+	libstorage \
+	libsurfaceflinger \
+	libsurfaceflinger_client \
+	libsvoxpico \
+	libsystem_server \
+	libsysutils \
+	libthread_db \
+	libtinyxml \
+	libtomcrypt \
+	libtommath \
+	libttspico \
+	libttssynthproxy \
+	libui \
+	libunz \
+	libutil \
+	libutils \
+	libv8 \
+	libvisualizer \
+	libvorbisidec \
+	libvpx \
+	libwebcore \
+	libwpa_client \
+	libxml2 \
+	libz \
+	libzipfile \
+	lights.kraken \
+	lights.qsd8k \
+	line_endings \
+	linker \
+	localize \
+	logcat \
+	logwrapper \
+	lsd \
+	mahimahi-keypad.kcm \
+	make_cfst \
+	makedict \
+	make_ext4fs \
+	make_g2g \
+	makekeycodes \
+	make_ve_grammar \
+	mediaserver \
+	minigzip \
+	mkbootfs \
+	mkbootimg \
+	mksdcard \
+	mksnapshot \
+	mkstubs \
+	mkuserimg.sh \
+	mkyaffs2image \
+	monkey \
+	monkeyrunner \
+	mtpd \
+	ndc \
+	netcfg \
+	netd \
+	ninepatch \
+	oauth \
+	obbtool \
+	omx_tests \
+	org.eclipse.core.commands_3.4.0.I20080509-2000 \
+	org.eclipse.equinox.common_3.4.0.v20080421-2006 \
+	org.eclipse.jface_3.4.2.M20090107-0800 \
+	org-netbeans-api-visual \
+	org-openide-util \
+	osgi \
+	pand \
+	parseStringTest \
+	ping \
+	platform.xml \
+	pm \
+	post_trace \
+	pppd \
+	preload \
+	profile_pid \
+	profile_trace \
+	q2dm \
+	q2g \
+	qwerty2.kcm \
+	qwerty.kcm \
+	racoon \
+	read_addr \
+	read_method \
+	read_pid \
+	read_trace \
+	rgb2565 \
+	rild \
+	rsg-generator \
+	run-as \
+	schedtest \
+	screenshot2 \
+	sdcard \
+	sdklib \
+	sdkmanager \
+	sdkstats \
+	sdkuilib \
+	sdk_v4 \
+	sdk_v5 \
+	sdk_v6 \
+	sdk_v7 \
+	sdk_v8 \
+	sdptool \
+	service \
+	servicemanager \
+	services \
+	sh \
+	sig \
+	sig-check \
+	sig-create \
+	signapk \
+	signature-tools \
+	simg2img \
+	soslim \
+	spec-progress \
+	sqlite3 \
+	sqlite-jdbc \
+	stack_dump \
+	stringtemplate \
+	surfaceflinger \
+	svc \
+	swing-worker-1.1 \
+	swt \
+	system_server \
+	tc \
+	temp_layoutlib \
+	test_g2g \
+	test-progress \
+	test-progress-new \
+	test_swiarb \
+	test_zipfile \
+	toolbox \
+	traceview \
+	tuttle2.kcm \
+	uix \
+	usbtest \
+	vdc \
+	vm-tests \
+	vold \
+	wdsclient \
+	wpa_supplicant \
+	wpa_supplicant.conf \
+	xmlwriter \
+	yuv420sp2rgb \
+	zipalign
+