[PATCH 1/1] auto disable cross for kmod build against distro kernels

[Felix Moessbauer <felix.moessbauer@siemens.com>]

Cross compiling kernel modules for distro kernels is not supported in debian.
To simplify downstream kernel module builds, we automatically turn off cross
compilation for a user-provided module when building it for a distro kernel.

This patch further replaces the hard-coded list of distro kernels with
the DISTRO_KERNELS variable to avoid code duplication.

Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
---
 RECIPE-API-CHANGELOG.md                       |  6 +++++
 .../example-module/example-module.bb          | 22 -------------------
 meta/recipes-kernel/linux-module/module.inc   | 10 +++++++++
 3 files changed, 16 insertions(+), 22 deletions(-)

diff --git a/RECIPE-API-CHANGELOG.md b/RECIPE-API-CHANGELOG.md
index bea12871..b1e5a5ab 100644
--- a/RECIPE-API-CHANGELOG.md
+++ b/RECIPE-API-CHANGELOG.md
@@ -566,3 +566,9 @@ supported, but a warning is issued when it is used. Future versions will drop
 When building a custom kernel module, the `KBuild` file might be located in
 a subdirectory. To support this use-case, set `MODULE_DIR=$(PWD)/subdir` in
 the module build recipe.
+
+### Automatically disable cross for kmod builds against distro kernels
+
+Cross compiling kernel modules for distro kernels is not supported in debian.
+To simplify downstream kernel module builds, we automatically turn of cross
+compilation for a user-provided module when building it for a distro kernel.
diff --git a/meta-isar/recipes-kernel/example-module/example-module.bb b/meta-isar/recipes-kernel/example-module/example-module.bb
index 5ebed102..22f3cc47 100644
--- a/meta-isar/recipes-kernel/example-module/example-module.bb
+++ b/meta-isar/recipes-kernel/example-module/example-module.bb
@@ -5,28 +5,6 @@
 #
 # SPDX-License-Identifier: MIT
 
-# Cross-compilation is not supported for the default Debian kernels.
-# For example, package with kernel headers for ARM:
-#   linux-headers-armmp
-# has hard dependencies from linux-compiler-gcc-4.8-arm, what
-# conflicts with the host binaries.
-python() {
-    if d.getVar('KERNEL_NAME') in [
-        'armmp',
-        'arm64',
-        'rpi-rpfv',
-        'amd64',
-        '686-pae',
-        '4kc-malta',
-        'riscv64',
-        'kernel',
-        'kernel7',
-        'kernel7l',
-        'kernel8',
-    ]:
-        d.setVar('ISAR_CROSS_COMPILE', '0')
-}
-
 require recipes-kernel/linux-module/module.inc
 
 SRC_URI += "file://src"
diff --git a/meta/recipes-kernel/linux-module/module.inc b/meta/recipes-kernel/linux-module/module.inc
index 269da6ae..eddbf177 100644
--- a/meta/recipes-kernel/linux-module/module.inc
+++ b/meta/recipes-kernel/linux-module/module.inc
@@ -28,6 +28,16 @@ SRC_URI += "file://debian/"
 
 AUTOLOAD ?= ""
 
+# Cross-compilation is not supported for the default Debian kernels.
+# For example, package with kernel headers for ARM:
+#   linux-headers-armmp
+# has hard dependencies from linux-compiler-gcc-4.8-arm, what
+# conflicts with the host binaries.
+python() {
+    if d.getVar('KERNEL_NAME') in d.getVar('DISTRO_KERNELS').split():
+        d.setVar('ISAR_CROSS_COMPILE', '0')
+}
+
 inherit dpkg
 
 TEMPLATE_FILES = "debian/control.tmpl \
-- 
2.39.2