diff --git a/Makefile b/Makefile
index 4088946104cf..3b8feb6bea93 100644
--- a/Makefile
+++ b/Makefile
@@ -131,6 +131,20 @@ $(if $(word 2, $(KBUILD_EXTMOD)), \
 
 export KBUILD_EXTMOD
 
+# ANDROID: set up mixed-build support. mixed-build allows device kernel modules
+# to be compiled against a GKI kernel. This approach still uses the headers and
+# Kbuild from device kernel, so care must be taken to ensure that those headers match.
+ifdef KBUILD_MIXED_TREE
+# Need vmlinux.symvers for modpost and System.map for depmod, check whether they exist in KBUILD_MIXED_TREE
+required_mixed_files=vmlinux.symvers System.map
+$(if $(filter-out $(words $(required_mixed_files)), \
+		$(words $(wildcard $(add-prefix $(KBUILD_MIXED_TREE)/,$(required_mixed_files))))),,\
+	$(error KBUILD_MIXED_TREE=$(KBUILD_MIXED_TREE) doesn't contain $(required_mixed_files)))
+endif
+
+mixed-build-prefix = $(if $(KBUILD_MIXED_TREE),$(KBUILD_MIXED_TREE)/)
+export KBUILD_MIXED_TREE
+
 # Kbuild will save output files in the current working directory.
 # This does not need to match to the root of the kernel source tree.
 #
@@ -655,11 +669,13 @@ drivers-y	+= virt/
 libs-y		:= lib/
 endif # KBUILD_EXTMOD
 
+ifndef KBUILD_MIXED_TREE
 # The all: target is the default when no target is given on the
 # command line.
 # This allow a user to issue only 'make' to build a kernel including modules
 # Defaults to vmlinux, but the arch makefile usually adds further targets
 all: vmlinux
+endif
 
 CFLAGS_GCOV	:= -fprofile-arcs -ftest-coverage \
 	$(call cc-option,-fno-tree-loop-im) \
@@ -1232,8 +1248,10 @@ cmd_link-vmlinux =                                                 \
 	$(CONFIG_SHELL) $< "$(LD)" "$(KBUILD_LDFLAGS)" "$(LDFLAGS_vmlinux)";    \
 	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
 
+ifndef KBUILD_MIXED_TREE
 vmlinux: scripts/link-vmlinux.sh autoksyms_recursive $(vmlinux-deps) FORCE
 	+$(call if_changed,link-vmlinux)
+endif
 
 targets := vmlinux
 
@@ -1454,7 +1472,9 @@ endif
 # using awk while concatenating to the final file.
 
 PHONY += modules
-modules: $(if $(KBUILD_BUILTIN),vmlinux) modules_check modules_prepare
+# if KBUILD_BUILTIN && !KBUILD_MIXED_TREE, depend on vmlinux
+modules: $(if $(KBUILD_BUILTIN), $(if $(KBUILD_MIXED_TREE),,vmlinux))
+modules: modules_check modules_prepare
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
 
 PHONY += modules_check
@@ -1488,8 +1508,8 @@ _modinst_:
 		ln -s $(CURDIR) $(MODLIB)/build ; \
 	fi
 	@sed 's:^:kernel/:' modules.order > $(MODLIB)/modules.order
-	@cp -f modules.builtin $(MODLIB)/
-	@cp -f $(objtree)/modules.builtin.modinfo $(MODLIB)/
+	@cp -f $(mixed-build-prefix)modules.builtin $(MODLIB)/
+	@cp -f $(or $(mixed-build-prefix),$(objtree)/)modules.builtin.modinfo $(MODLIB)/
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst
 
 # This depmod is only for convenience to give the initial
@@ -1868,7 +1888,7 @@ descend: $(build-dirs)
 $(build-dirs): prepare
 	$(Q)$(MAKE) $(build)=$@ \
 	single-build=$(if $(filter-out $@/, $(filter $@/%, $(KBUILD_SINGLE_TARGETS))),1) \
-	need-builtin=1 need-modorder=1
+	$(if $(KBUILD_MIXED_TREE),,need-builtin=1) need-modorder=1
 
 clean-dirs := $(addprefix _clean_, $(clean-dirs))
 PHONY += $(clean-dirs) clean
@@ -2002,7 +2022,7 @@ quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN   $(wildcard $(rm-files))
 # Run depmod only if we have System.map and depmod is executable
 quiet_cmd_depmod = DEPMOD  $(KERNELRELEASE)
       cmd_depmod = $(CONFIG_SHELL) $(srctree)/scripts/depmod.sh $(DEPMOD) \
-                   $(KERNELRELEASE)
+                   $(KERNELRELEASE) $(mixed-build-prefix)
 
 # read saved command lines for existing targets
 existing-targets := $(wildcard $(sort $(targets)))
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index e8bac7553539..6f637794fe17 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -46,6 +46,8 @@ include scripts/Kbuild.include
 # for ld_flags
 include scripts/Makefile.lib
 
+mixed-build-prefix = $(if $(KBUILD_MIXED_TREE),$(KBUILD_MIXED_TREE)/)
+
 MODPOST = scripts/mod/modpost								\
 	$(if $(CONFIG_MODVERSIONS),-m)							\
 	$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a)					\
@@ -67,7 +69,7 @@ else
 
 ifeq ($(KBUILD_EXTMOD),)
 
-input-symdump := vmlinux.symvers
+input-symdump := $(mixed-build-prefix)vmlinux.symvers
 output-symdump := Module.symvers
 module_srcpath := $(srctree)
 
diff --git a/scripts/depmod.sh b/scripts/depmod.sh
index 3643b4f896ed..2de598d4691a 100755
--- a/scripts/depmod.sh
+++ b/scripts/depmod.sh
@@ -3,14 +3,15 @@
 #
 # A depmod wrapper used by the toplevel Makefile
 
-if test $# -ne 2; then
-	echo "Usage: $0 /sbin/depmod <kernelrelease>" >&2
+if test $# -ne 2 -a $# -ne 3; then
+	echo "Usage: $0 /sbin/depmod <kernelrelease> [System.map folder]" >&2
 	exit 1
 fi
 DEPMOD=$1
 KERNELRELEASE=$2
+KBUILD_MIXED_TREE=$3
 
-if ! test -r System.map ; then
+if ! test -r ${KBUILD_MIXED_TREE}System.map ; then
 	echo "Warning: modules_install: missing 'System.map' file. Skipping depmod." >&2
 	exit 0
 fi
@@ -41,7 +42,7 @@ if $depmod_hack_needed; then
 	KERNELRELEASE=99.98.$KERNELRELEASE
 fi
 
-set -- -ae -F System.map
+set -- -ae -F ${KBUILD_MIXED_TREE}System.map
 if test -n "$INSTALL_MOD_PATH"; then
 	set -- "$@" -b "$INSTALL_MOD_PATH"
 fi