[Buildroot] [PATCH v5] br2-ext linux-kernel-extensions support
Yann E. MORIN
yann.morin.1998 at free.fr
Fri Sep 27 18:05:11 UTC 2019
Robert, All,
On 2019-09-27 10:26 -0500, robert.mccabe at rockwellcollins.com spake thusly:
> From: "McCabe, Robert J" <robert.mccabe at rockwellcollins.com>
>
> Allows br2-externals to inject custom code into the kernel tree.
>
> Signed-off-by: McCabe, Robert J <robert.mccabe at rockwellcollins.com>
Reviewed-by: Yann E. MORIN <yann.morin.1998 at free.fr>
However, see a small nitpick below...
> ---
> docs/manual/customize-outside-br.txt | 14 ++++++++++++++
> linux/linux.mk | 13 +++++++++----
> 2 files changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/docs/manual/customize-outside-br.txt b/docs/manual/customize-outside-br.txt
> index 6ab01bcb1f..0588c478e7 100644
> --- a/docs/manual/customize-outside-br.txt
> +++ b/docs/manual/customize-outside-br.txt
> @@ -219,6 +219,12 @@ BR2_ROOTFS_OVERLAY=$(BR2_EXTERNAL_BAR_42_PATH)/board/<boardname>/overlay/
> BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE=$(BR2_EXTERNAL_BAR_42_PATH)/board/<boardname>/kernel.config
> ----
>
> +===== Custom linux-kernel-extensions
> +
> +Custom code may be added to the Linux kernel tree as discussed in
I think the wording is inadequate. We don't really want to discuss
"custom code". The documentation currently does not delves into the
details of what a linux extension does, except it somehow "prepares" the
linux tree; the macro itself is suffixed with _PREPARE_KERNEL:
09: define FOO_PREPARE_KERNEL
10: $(FOO_DIR)/prepare-kernel-tree.sh --linux-dir=$(@D)
11: endef
I would just rephrase that as:
Custom linux extensions (see xref:linux-kernel-ext[]) can be added
by storing them in the `linux/` director at the root of your
br2-external tree.
But apart from that, I'm OK with the patch.
Regards,
Yann E. MORIN.
> +xref:linux-kernel-ext[] by adding +linux/linux-ext-*.mk+ to the
> +br2-external tree.
> +
> ===== Example layout
>
> Here is an example layout using all features of br2-external (the sample
> @@ -314,6 +320,14 @@ illustration, of course):
> | |$(eval $(toolchain-external-package))
> | `----
> |
> + |- linux/Config.ext.in
> + | |config BR2_LINUX_KERNEL_EXT_EXAMPLE_DRIVER
> + | | bool "example-external-driver"
> + | | help
> + | | Example external driver
> + | |---
> + |- linux/linux-ext-example-driver.mk
> + |
> |- configs/my-board_defconfig
> | |BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_BAR_42_PATH)/patches/"
> | |BR2_ROOTFS_OVERLAY="$(BR2_EXTERNAL_BAR_42_PATH)/board/my-board/overlay/"
> diff --git a/linux/linux.mk b/linux/linux.mk
> index 29d2f0ee69..921558eeb2 100644
> --- a/linux/linux.mk
> +++ b/linux/linux.mk
> @@ -513,14 +513,19 @@ endef
> #
> # Note: our package infrastructure uses the full-path of the last-scanned
> # Makefile to determine what package we're currently defining, using the
> -# last directory component in the path. As such, including other Makefile,
> -# like below, before we call one of the *-package macro is usally not
> -# working.
> +# last directory component in the path. As such, including other Makefiles,
> +# like below, before we call one of the *-package macros usually doesn't
> +# work.
> # However, since the files we include here are in the same directory as
> # the current Makefile, we are OK. But this is a hard requirement: files
> -# included here *must* be in the same directory!
> +# included here *must* either be in this same directory OR within a
> +# another directory with the name "linux" (in the BR2_EXTERNAL case).
> include $(sort $(wildcard linux/linux-ext-*.mk))
>
> +#Import linux-kernel-extensions from externals
> +include $(sort $(wildcard $(foreach ext,$(BR2_EXTERNAL_DIRS), \
> + $(ext)/linux/linux-ext-*.mk)))
> +
> LINUX_PATCH_DEPENDENCIES += $(foreach ext,$(LINUX_EXTENSIONS),\
> $(if $(BR2_LINUX_KERNEL_EXT_$(call UPPERCASE,$(ext))),$(ext)))
>
> --
> 2.17.1
>
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