[Buildroot] [PATCH 2/2 v9] package/linux-backports: switch to using the kernel-module infra

[Romain Naour <romain.naour@openwide.fr>]

Hi Yann, all

Le 23/07/2015 23:55, Yann E. MORIN a ?crit :
> linux-backports manually generates its autoconf.h header, which needs a
> .config file.
> 
> Using a pre- or post-configure hook does not really work, because
> generating that file touches the .config, and thus our .stamp files ar
> enot longer properly time-ordered and running a subsequent make would
> incorrectly believe it has to rebuild linux-backports.
> 
> So, even though this is not a fixup proper, we generate that file from
> the _KCONFIG_FIXUP_CMDS to ensure the stampt file is created after we
> touch .config.
> 
> Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> Cc: Petr Vorel <petr.vorel@gmail.com>
> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Reviewed-by: Romain Naour <romain.naour@openwide.fr>

Tested with a x86 3.2 kernel.
Tested-by: Romain Naour <romain.naour@openwide.fr>

> 
> ---
> Changes v8 -> v9:
>   - comment tricky constructs  (Thomas)
>   - use _KCONFIG_FIXUP_CMDS instead of POST_CONFIGURE_HOOKS
> ---
>  package/linux-backports/linux-backports.mk | 48 +++++++++++++++++++-----------
>  1 file changed, 30 insertions(+), 18 deletions(-)
> 
> diff --git a/package/linux-backports/linux-backports.mk b/package/linux-backports/linux-backports.mk
> index e4ac9f4..44ac7e7 100644
> --- a/package/linux-backports/linux-backports.mk
> +++ b/package/linux-backports/linux-backports.mk
> @@ -11,33 +11,44 @@ LINUX_BACKPORTS_SITE = $(BR2_KERNEL_MIRROR)/linux/kernel/projects/backports/stab
>  LINUX_BACKPORTS_LICENSE = GPLv2
>  LINUX_BACKPORTS_LICENSE_FILES = COPYING
>  
> -LINUX_BACKPORTS_DEPENDENCIES = linux
> -
> -LINUX_BACKPORTS_MAKE_OPTS = \
> -	$(LINUX_MAKE_FLAGS) \
> -	KLIB_BUILD=$(LINUX_DIR) \
> -	KLIB=$(TARGET_DIR)
> -
>  ifeq ($(BR2_PACKAGE_LINUX_BACKPORTS_USE_DEFCONFIG),y)
>  LINUX_BACKPORTS_KCONFIG_FILE = $(LINUX_BACKPORTS_DIR)/defconfigs/$(call qstrip,$(BR2_PACKAGE_LINUX_BACKPORTS_DEFCONFIG))
>  else ifeq ($(BR2_PACKAGE_LINUX_BACKPORTS_USE_CUSTOM_CONFIG),y)
>  LINUX_BACKPORTS_KCONFIG_FILE = $(call qstrip,$(BR2_PACKAGE_LINUX_BACKPORTS_CUSTOM_CONFIG_FILE))
>  endif
>  
> -define LINUX_BACKPORTS_BUILD_CMDS
> -	$(TARGET_MAKE_ENV) $(MAKE) $(LINUX_BACKPORTS_MAKE_OPTS) -C $(@D)
> -endef
> -
> -define LINUX_BACKPORTS_INSTALL_TARGET_CMDS
> -	$(TARGET_MAKE_ENV) $(MAKE) $(LINUX_BACKPORTS_MAKE_OPTS) \
> -		-C $(LINUX_DIR) M=$(@D) \
> -		INSTALL_MOD_DIR=backports \
> -		modules_install
> -endef
> -
>  LINUX_BACKPORTS_KCONFIG_FRAGMENT_FILES = $(call qstrip,$(BR2_PACKAGE_LINUX_BACKPORTS_CONFIG_FRAGMENT_FILES))
>  LINUX_BACKPORTS_KCONFIG_OPTS = $(LINUX_BACKPORTS_MAKE_OPTS)
>  
> +# linux-backports' build system expects the config options to be present
> +# in the environment, and it is so when using their custom buildsystem,
> +# because they are set in the main Makefile, which then calls a second
> +# Makefile.
> +#
> +# In our case, we do not use that first Makefile. So, we parse the
> +# .config file, filter-out comment lines and put the rest as command
> +# line variables.
> +#
> +# LINUX_BACKPORTS_MAKE_OPTS is used by the kconfig-package infra, while
> +# LINUX_BACKPORTS_MODULE_MAKE_OPTS is used by the kernel-module infra.
> +#
> +LINUX_BACKPORTS_MAKE_OPTS = \
> +	BACKPORT_DIR=$(@D) \
> +	KLIB_BUILD=$(LINUX_DIR) \
> +	KLIB=$(TARGET_DIR)/lib/modules/$(LINUX_VERSION_PROBED) \
> +	INSTALL_MOD_DIR=backports \
> +	`sed -r -e '/^\#/d;' $(@D)/.config`

At first read, I was wondering why $(SED) wasn't used here, but since it
contains -i option we can't use it here. So the .config is not modified.

Thanks Yann for the explanation on IRC ;-)

Thanks Petr for your initial work on this.

Best regards,
Romain

> +
> +LINUX_BACKPORTS_MODULE_MAKE_OPTS = $(LINUX_BACKPORTS_MAKE_OPTS)
> +
> +# This file is not automatically generated by 'oldconfig' that we use in
> +# the kconfig-package infrastructure. In the linux buildsystem, it is
> +# generated by running silentoldconfig, but that's not the case for
> +# linux-backports: it uses a hand-crafted rule to generate that file.
> +define LINUX_BACKPORTS_KCONFIG_FIXUP_CMDS
> +	$(MAKE) -C $(@D) $(LINUX_BACKPORTS_MAKE_OPTS) backport-include/backport/autoconf.h
> +endef
> +
>  # Checks to give errors that the user can understand
>  ifeq ($(BR_BUILDING),y)
>  
> @@ -55,6 +66,7 @@ endif
>  
>  endif # BR_BUILDING
>  
> +$(eval $(kernel-module))
>  $(eval $(kconfig-package))
>  
>  # linux-backports' own .config file needs options from the kernel's own
>