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

[Laurent Pinchart]

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.

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

> > +
> > +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,

Laurent Pinchart