From 9b81932ff1baae4b708bc586524a2fa160699137 Mon Sep 17 00:00:00 2001
From: Ben Hutchings <ben@decadent.org.uk>
Date: Tue, 8 Jul 2025 13:30:55 +0200
Subject: [PATCH] android: Enable building binder as module

Bug-Debian: https://bugs.debian.org/901492

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

- Change the Makefiles to build the driver as an object with the
  "_linux" suffix (which is what Waydroid expects)
- Change config symbol types to tristate
- Add a module description, because modpost warns about missing
  descriptions

Gbp-Pq: Topic debian
Gbp-Pq: Name android-enable-building-binder-as-module.patch
---
 drivers/android/Kconfig        | 2 +-
 drivers/android/Makefile       | 7 ++++---
 drivers/android/binder.c       | 3 +++
 drivers/android/binder_alloc.c | 2 +-
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig
index e2e402c9d17..7e5d76ecd45 100644
--- 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
 	depends on NET
 	default n
diff --git a/drivers/android/Makefile b/drivers/android/Makefile
index e0c650d3898..eae81bed1fb 100644
--- a/drivers/android/Makefile
+++ b/drivers/android/Makefile
@@ -1,7 +1,8 @@
 # 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 binder_netlink.o
-obj-$(CONFIG_ANDROID_BINDER_ALLOC_KUNIT_TEST)	+= tests/
+obj-$(CONFIG_ANDROID_BINDER_IPC)	+= binder_linux.o
+binder_linux-y := binder.o binder_alloc.o binder_netlink.o
+binder_linux-$(CONFIG_ANDROID_BINDERFS)	+= binderfs.o
+binder_linux-$(CONFIG_ANDROID_BINDER_ALLOC_KUNIT_TEST)	+= tests/
 obj-$(CONFIG_ANDROID_BINDER_IPC_RUST)	+= binder/
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 33e4dad0915..44ac3e3c96b 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -7171,3 +7171,6 @@ device_initcall(binder_init);
 
 #define CREATE_TRACE_POINTS
 #include "binder_trace.h"
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Android Binder IPC Driver");
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index d5ed64543bb..62736c76868 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -39,7 +39,7 @@ 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...) \
-- 
2.30.2