From: Ben Hutchings <ben@decadent.org.uk>
Date: Fri, 22 Jun 2018 17:27:00 +0100
Subject: android: Enable building ashmem and binder as modules
Bug-Debian: https://bugs.debian.org/901492

We want to enable use of the Android ashmem and binder drivers to
support Anbox, but they should not be built-in as that would waste
resources and increase security attack surface on systems that don't
need them.

- Add a MODULE_LICENSE declaration to ashmem
- Change the Makefiles to build each driver as an object with the
  "_linux" suffix (which is what Anbox expects)
- Change config symbol types to tristate

Update:
In upstream commit 721412ed3d titled "staging: remove ashmem" the ashmem
driver was removed entirely. Secondary commit message:
"The mainline replacement for ashmem is memfd, so remove the legacy
code from drivers/staging/"
Consequently, the ashmem part of this patch has been removed.
---
 drivers/android/Kconfig          | 2 +-
 drivers/android/Makefile         | 7 ++++---
 drivers/android/binder_alloc.c   | 2 +-
 3 files changed, 6 insertions(+), 5 deletions(-)

--- a/drivers/android/Kconfig
+++ b/drivers/android/Kconfig
@@ -2,7 +2,7 @@
 menu "Android"
 
 config ANDROID_BINDER_IPC
-	bool "Android Binder IPC Driver"
+	tristate "Android Binder IPC Driver"
 	depends on MMU
 	default n
 	help
--- a/drivers/android/Makefile
+++ b/drivers/android/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 ccflags-y += -I$(src)			# needed for trace events
 
-obj-$(CONFIG_ANDROID_BINDERFS)		+= binderfs.o
-obj-$(CONFIG_ANDROID_BINDER_IPC)	+= binder.o binder_alloc.o
-obj-$(CONFIG_ANDROID_BINDER_IPC_SELFTEST) += binder_alloc_selftest.o
+obj-$(CONFIG_ANDROID_BINDER_IPC)	+= binder_linux.o
+binder_linux-y := binder.o binder_alloc.o
+binder_linux-$(CONFIG_ANDROID_BINDERFS)	+= binderfs.o
+binder_linux-$(CONFIG_ANDROID_BINDER_IPC_SELFTEST) += binder_alloc_selftest.o
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -38,7 +38,7 @@ enum {
 };
 static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
 
-module_param_named(debug_mask, binder_alloc_debug_mask,
+module_param_named(alloc_debug_mask, binder_alloc_debug_mask,
 		   uint, 0644);
 
 #define binder_alloc_debug(mask, x...) \
