[libcamera-devel] [PATCH] utils: Add kernel headers update script

[Kieran Bingham]

On 08/03/2021 13:06, Laurent Pinchart wrote:
> Hi Kieran,
> 
> On Mon, Mar 08, 2021 at 12:23:19PM +0000, Kieran Bingham wrote:
>> On 03/03/2021 17:39, Laurent Pinchart wrote:
>>> Add a script to update the local copy of kernel headers (in
>>> include/linux/) from a Linux kernel git tree. The script handles header
>>> installation, manual processing of the IPU3 header that is still in
>>> staging, and update of the README file.
>>>
>>> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
>>> ---
>>>  utils/update-kernel-headers.sh | 78 ++++++++++++++++++++++++++++++++++
>>>  1 file changed, 78 insertions(+)
>>>  create mode 100755 utils/update-kernel-headers.sh
>>>
>>> diff --git a/utils/update-kernel-headers.sh b/utils/update-kernel-headers.sh
>>> new file mode 100755
>>> index 000000000000..f5d91c8a8c08
>>> --- /dev/null
>>> +++ b/utils/update-kernel-headers.sh
>>> @@ -0,0 +1,78 @@
>>> +#!/bin/sh
>>> +
>>> +# SPDX-License-Identifier: GPL-2.0-or-later
>>> +# Update the kernel headers copy from a kernel source tree
>>> +
>>> +if [ $# != 1 ] ; then
>>> +	echo "Usage: $0 <kernel dir>"
>>> +	exit 1
>>> +fi
>>> +
>>> +header_dir="$(dirname "$(realpath "$0")")/../include/linux"
>>> +kernel_dir="$1"
>>> +
>>> +# Bail out if the directory doesn't contain kernel sources
>>> +line=$(head -3 "${kernel_dir}/Kbuild" 2>/dev/null | tail -1)
>>> +if [ "$line" != "# Kbuild for top-level directory of the kernel" ] ; then
>>> +	echo "Directory ${kernel_dir} doesn't contain a kernel source tree"
>>> +	exit 1
>>> +fi
>>> +
>>> +if [ ! -d "${kernel_dir}/.git" ] ; then
>>> +	echo "Directory ${kernel_dir} doesn't contain a git tree"
>>> +	exit 1
>>> +fi
>>> +
>>> +# Install the headers to a temporary directory
>>> +install_dir=$(mktemp -d)
>>> +if [ ! -d "${install_dir}" ] ; then
>>> +	echo "Failed to create temporary directory"
>>> +	exit 1
>>> +fi
>>> +
>>> +trap "rm -rf ${install_dir}" EXIT
>>> +
>>> +set -e
>>> +make -C "${kernel_dir}" O="${install_dir}" headers_install
>>> +set +e
>>> +
>>> +# Copy the headers
>>> +headers="
>>> +	drm/drm_fourcc.h
>>> +	linux/dma-buf.h
>>> +	linux/dma-heap.h
>>> +	linux/media-bus-format.h
>>> +	linux/media.h
>>> +	linux/rkisp1-config.h
>>> +	linux/v4l2-common.h
>>> +	linux/v4l2-controls.h
>>> +	linux/v4l2-mediabus.h
>>> +	linux/v4l2-subdev.h
>>> +	linux/videodev2.h
>>> +"
>>> +
>>> +for header in $headers ; do
>>> +	name=$(basename "${header}")
>>> +	cp "${install_dir}/usr/include/${header}" "${header_dir}/${name}"
>>> +done
>>> +
>>> +# The IPU3 header is a special case, as it's stored in staging. Handle it
>>> +# manually.
>>> +(cd "${install_dir}" ; "${kernel_dir}scripts/headers_install.sh" \
>>> +	"${kernel_dir}/drivers/staging/media/ipu3/include/intel-ipu3.h" \
>>> +	"${header_dir}/intel-ipu3.h")
>>> +
>>> +# Update the README file
>>> +version=$(git --git-dir="${kernel_dir}/.git" describe)
>>
>> Should this have any other parameters?
>>
>>  --always --tags --dirty ?
> 
> We're expected to run this on a kernel git tree, if it doesn't have any
> tag, there's something clearly wrong :-) --always shouldn't be needed.
> Similarly, for --tags, as we're tracking mainline tags are annotated.
> If there are local tags in a kernel tree on top a mailine tag, ignoring
> them would be less confusing I think.

Are we always guaranteed to have pull tags locally?

Aren't there conditions where the local git tree might not have the
tags? (Perhaps not, but that's why I suggested the always).

> 
> --dirty sounds good, and we should actually error out in that case. I'll
> submit a v2.

Erroring out in that case sounds best indeed.



> 
>>> +
>>> +cat <<EOF > "${header_dir}/README"
>>> +# SPDX-License-Identifier: CC0-1.0
>>> +
>>> +Files in this directory are imported from ${version} of the Linux kernel. Do not
>>> +modify them manually.
>>> +EOF
>>> +
>>> +# Cleanup
>>> +rm -rf "${install_dir}"
>>> +
>>> +echo "Kernel headers updated"
>>
>> Are there any other manual steps required which should be mentioned at
>> the end of the script so they do not get missed by someone running it?
> 
> How about this ?
> 
> diff --git a/utils/update-kernel-headers.sh b/utils/update-kernel-headers.sh
> index f5d91c8a8c08..bb045d395359 100755
> --- a/utils/update-kernel-headers.sh
> +++ b/utils/update-kernel-headers.sh
> @@ -75,4 +75,9 @@ EOF
>  # Cleanup
>  rm -rf "${install_dir}"
> 
> -echo "Kernel headers updated"
> +cat <<EOF
> +----------------------------------------------------------------------
> +Kernel headers updated. Please review and up-port local changes before
> +committing.
> +----------------------------------------------------------------------
> +EOF
> 
>> Otherwise
>>
>> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> 

-- 
Regards
--
Kieran