From: Yann E. MORIN Date: Sat, 4 Apr 2020 12:10:21 +0000 (+0200) Subject: linux: allow packages to set kernel config options X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=0aed4c2dae76f28ca7a868e31622873222c410e8;p=buildroot.git linux: allow packages to set kernel config options Currently, the linux kernel will apply some fixups on its .config file, based on whether some packages are enabled or not. That list of conditional fixups is getting bigger and bigger with each new package that needs such fixups, culminating with the pending firewalld one [0]. Furthermore, these fixups are not accessible to packages in br2-external trees. Add a new per-package variable, that packages may set to the commands to run to fixup the kernel .config file, which is added at the end of the linux' own fixups. This opens the possibility to write things like; define FOO_LINUX_CONFIG_FIXUPS $(call KCONFIG_ENABLE_OPT,BLA) endef Of course, it also opens the way to run arbitrary commands in there, but any alternative that would be declarative only, such as a list of options to enable or disable (as an example): FOO_LINUX_CONFIG_FIXUPS = +BAR -FOO +BUZ="value" .. is not very nice either, and such lists fall flat when a value would have a space. For packages that we have in-tree, we can ensure they won't play foul with their _LINUX_CONFIG_FIXUPS. For packages in br2-external trees, there's nothing we can do; users already have the opportunity to hack into the linux configure process by providing LINUX_PRE_CONFIGURE_HOOKS or LINUX_POST_CONFIGURE_HOOKS anyway... .. which brings the question of why we don't use that to implement the per-package fixups. We don't, because _PRE or _POST_CONFIGURE_HOOKS are run after we run 'make oldconfig' to sanitise the mangled .config. [0] http://lists.busybox.net/pipermail/buildroot/2020-March/278683.html Signed-off-by: Yann E. MORIN Cc: Thomas Petazzoni Cc: Thomas De Schampheleire Cc: Peter Korsgaard Cc: Adam Duskett Signed-off-by: Thomas Petazzoni --- diff --git a/docs/manual/adding-packages-generic.txt b/docs/manual/adding-packages-generic.txt index ed1e6acf57..568daaeb8d 100644 --- a/docs/manual/adding-packages-generic.txt +++ b/docs/manual/adding-packages-generic.txt @@ -577,6 +577,14 @@ different steps of the build process. This is seldom used, as packages rarely have custom rules. *Do not use this variable*, unless you really know that you need to print help. +* +LIBFOO_LINUX_CONFIG_FIXUPS+ lists the Linux kernel configuration + options that are needed to build and use this package, and without + which the package is fundamentally broken. This shall be a set of + calls to one of the kconfig tweaking option: `KCONFIG_ENABLE_OPT`, + `KCONFIG_DISABLE_OPT`, or `KCONFIG_SET_OPT`. + This is seldom used, as package usually have no strict requirements on + the kernel options. + The preferred way to define these variables is: ---------------------- diff --git a/linux/linux.mk b/linux/linux.mk index 9a618db0e0..eb13920d57 100644 --- a/linux/linux.mk +++ b/linux/linux.mk @@ -421,6 +421,7 @@ define LINUX_KCONFIG_FIXUP_CMDS $(call KCONFIG_ENABLE_OPT,CONFIG_SECURITY) $(call KCONFIG_ENABLE_OPT,CONFIG_SECURITY_NETWORK) $(call KCONFIG_ENABLE_OPT,CONFIG_SECURITY_SELINUX)) + $(PACKAGES_LINUX_CONFIG_FIXUPS) endef ifeq ($(BR2_LINUX_KERNEL_DTS_SUPPORT),y) diff --git a/package/pkg-generic.mk b/package/pkg-generic.mk index 8cd5a7ff62..946dc6d561 100644 --- a/package/pkg-generic.mk +++ b/package/pkg-generic.mk @@ -1083,6 +1083,9 @@ endif ifneq ($$($(2)_USERS),) PACKAGES_USERS += $$($(2)_USERS)$$(sep) endif +ifneq ($$($(2)_LINUX_CONFIG_FIXUPS),) +PACKAGES_LINUX_CONFIG_FIXUPS += $$($(2)_LINUX_CONFIG_FIXUPS)$$(sep) +endif TARGET_FINALIZE_HOOKS += $$($(2)_TARGET_FINALIZE_HOOKS) ROOTFS_PRE_CMD_HOOKS += $$($(2)_ROOTFS_PRE_CMD_HOOKS) KEEP_PYTHON_PY_FILES += $$($(2)_KEEP_PY_FILES)