[PATCH v8 2/2] arm64: boot: Support Flat Image Tree
Masahiro Yamada
masahiroy at kernel.org
Fri Dec 1 20:56:01 CET 2023
On Sat, Dec 2, 2023 at 3:09 AM Simon Glass <sjg at chromium.org> wrote:
>
> Hi Masahiro,
>
> On Fri, 1 Dec 2023 at 10:30, Masahiro Yamada <masahiroy at kernel.org> wrote:
> >
> > On Fri, Dec 1, 2023 at 5:34 AM Simon Glass <sjg at chromium.org> wrote:
> > >
> > > Add a script which produces a Flat Image Tree (FIT), a single file
> > > containing the built kernel and associated devicetree files.
> > > Compression defaults to gzip which gives a good balance of size and
> > > performance.
> > >
> > > The files compress from about 86MB to 24MB using this approach.
> > >
> > > The FIT can be used by bootloaders which support it, such as U-Boot
> > > and Linuxboot. It permits automatic selection of the correct
> > > devicetree, matching the compatible string of the running board with
> > > the closest compatible string in the FIT. There is no need for
> > > filenames or other workarounds.
> > >
> > > Add a 'make image.fit' build target for arm64, as well.
> > >
> > > The FIT can be examined using 'dumpimage -l'.
> > >
> > > This features requires pylibfdt (use 'pip install libfdt'). It also
> > > requires compression utilities for the algorithm being used. Supported
> > > compression options are the same as the Image.xxx files. For now there
> > > is no way to change the compression other than by editing the rule for
> > > $(obj)/image.fit
> > >
> > > While FIT supports a ramdisk / initrd, no attempt is made to support
> > > this here, since it must be built separately from the Linux build.
> > >
> > > Signed-off-by: Simon Glass <sjg at chromium.org>
> > > ---
> > >
> > > Changes in v8:
> > > - Drop compatible string in FDT node
> > > - Correct sorting of MAINTAINERS to before ARM64 PORT
> > > - Turn compress part of the make_fit.py comment in to a sentence
> > > - Add two blank lines before parse_args() and setup_fit()
> > > - Use 'image.fit: dtbs' instead of BUILD_DTBS var
> > > - Use '$(<D)/dts' instead of '$(dir $<)dts'
> > > - Add 'mkimage' details Documentation/process/changes.rst
> > > - Allow changing the compression used
> > > - Tweak cover letter since there is only one clean-up patch
> > >
> > > Changes in v7:
> > > - Add Image as a dependency of image.fit
> > > - Drop kbuild tag
> > > - Add dependency on dtbs
> > > - Drop unnecessary path separator for dtbs
> > > - Rebase to -next
> > >
> > > Changes in v5:
> > > - Drop patch previously applied
> > > - Correct compression rule which was broken in v4
> > >
> > > Changes in v4:
> > > - Use single quotes for UIMAGE_NAME
> > >
> > > Changes in v3:
> > > - Drop temporary file image.itk
> > > - Drop patch 'Use double quotes for image name'
> > > - Drop double quotes in use of UIMAGE_NAME
> > > - Drop unnecessary CONFIG_EFI_ZBOOT condition for help
> > > - Avoid hard-coding "arm64" for the DT architecture
> > >
> > > Changes in v2:
> > > - Drop patch previously applied
> > > - Add .gitignore file
> > > - Move fit rule to Makefile.lib using an intermediate file
> > > - Drop dependency on CONFIG_EFI_ZBOOT
> > > - Pick up .dtb files separately from the kernel
> > > - Correct pylint too-many-args warning for write_kernel()
> > > - Include the kernel image in the file count
> > > - Add a pointer to the FIT spec and mention of its wide industry usage
> > > - Mention the kernel version in the FIT description
> > >
> > > Documentation/process/changes.rst | 9 +
> > > MAINTAINERS | 7 +
> > > arch/arm64/Makefile | 7 +-
> > > arch/arm64/boot/.gitignore | 1 +
> > > arch/arm64/boot/Makefile | 9 +-
> > > scripts/Makefile.lib | 13 ++
> > > scripts/make_fit.py | 291 ++++++++++++++++++++++++++++++
> > > 7 files changed, 334 insertions(+), 3 deletions(-)
> > > create mode 100755 scripts/make_fit.py
> > >
> > > diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
> > > index bb96ca0f774b..cad51bd5bd62 100644
> > > --- a/Documentation/process/changes.rst
> > > +++ b/Documentation/process/changes.rst
> > > @@ -62,6 +62,7 @@ Sphinx\ [#f1]_ 1.7 sphinx-build --version
> > > cpio any cpio --version
> > > GNU tar 1.28 tar --version
> > > gtags (optional) 6.6.5 gtags --version
> > > +mkimage (optional) 2017.01 mkimage --version
> > > ====================== =============== ========================================
> > >
> > > .. [#f1] Sphinx is needed only to build the Kernel documentation
> > > @@ -189,6 +190,14 @@ The kernel build requires GNU GLOBAL version 6.6.5 or later to generate
> > > tag files through ``make gtags``. This is due to its use of the gtags
> > > ``-C (--directory)`` flag.
> > >
> > > +mkimage
> > > +-------
> > > +
> > > +This tool is used when building a Flat Image Tree (FIT), commonly used on ARM
> > > +platforms. The tool is available via the ``u-boot-tools`` package or can be
> > > +built from the U-Boot source code. See the instructions at
> > > +https://docs.u-boot.org/en/latest/build/tools.html#building-tools-for-linux
> > > +
> > > System utilities
> > > ****************
> > >
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index 14587be87a33..9f3eb476ece4 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -3037,6 +3037,13 @@ F: drivers/mmc/host/sdhci-of-arasan.c
> > > N: zynq
> > > N: xilinx
> > >
> > > +ARM64 FIT SUPPORT
> > > +M: Simon Glass <sjg at chromium.org>
> > > +L: linux-arm-kernel at lists.infradead.org (moderated for non-subscribers)
> > > +S: Maintained
> > > +F: arch/arm64/boot/Makefile
> > > +F: scripts/make_fit.py
> > > +
> > > ARM64 PORT (AARCH64 ARCHITECTURE)
> > > M: Catalin Marinas <catalin.marinas at arm.com>
> > > M: Will Deacon <will at kernel.org>
> > > diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> > > index 1bd4fae6e806..6b893dc454b7 100644
> > > --- a/arch/arm64/Makefile
> > > +++ b/arch/arm64/Makefile
> > > @@ -150,7 +150,7 @@ libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
> > > # Default target when executing plain make
> > > boot := arch/arm64/boot
> > >
> > > -BOOT_TARGETS := Image vmlinuz.efi
> > > +BOOT_TARGETS := Image vmlinuz.efi image.fit
> > >
> > > PHONY += $(BOOT_TARGETS)
> > >
> > > @@ -162,7 +162,9 @@ endif
> > >
> > > all: $(notdir $(KBUILD_IMAGE))
> > >
> > > -vmlinuz.efi: Image
> > > +image.fit: dtbs
> > > +
> > > +vmlinuz.efi image.fit: Image
> > > $(BOOT_TARGETS): vmlinux
> > > $(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
> > >
> > > @@ -215,6 +217,7 @@ virtconfig:
> > > define archhelp
> > > echo '* Image.gz - Compressed kernel image (arch/$(ARCH)/boot/Image.gz)'
> > > echo ' Image - Uncompressed kernel image (arch/$(ARCH)/boot/Image)'
> > > + echo ' image.fit - Flat Image Tree (arch/$(ARCH)/boot/image.fit)'
> > > echo ' install - Install uncompressed kernel'
> > > echo ' zinstall - Install compressed kernel'
> > > echo ' Install using (your) ~/bin/installkernel or'
> > > diff --git a/arch/arm64/boot/.gitignore b/arch/arm64/boot/.gitignore
> > > index af5dc61f8b43..abaae9de1bdd 100644
> > > --- a/arch/arm64/boot/.gitignore
> > > +++ b/arch/arm64/boot/.gitignore
> > > @@ -2,3 +2,4 @@
> > > Image
> > > Image.gz
> > > vmlinuz*
> > > +image.fit
> > > diff --git a/arch/arm64/boot/Makefile b/arch/arm64/boot/Makefile
> > > index 1761f5972443..62efb533a9bc 100644
> > > --- a/arch/arm64/boot/Makefile
> > > +++ b/arch/arm64/boot/Makefile
> > > @@ -16,7 +16,8 @@
> > >
> > > OBJCOPYFLAGS_Image :=-O binary -R .note -R .note.gnu.build-id -R .comment -S
> > >
> > > -targets := Image Image.bz2 Image.gz Image.lz4 Image.lzma Image.lzo Image.zst
> > > +targets := Image Image.bz2 Image.gz Image.lz4 Image.lzma Image.lzo \
> > > + Image.zst image.fit
> > >
> > > $(obj)/Image: vmlinux FORCE
> > > $(call if_changed,objcopy)
> > > @@ -39,6 +40,12 @@ $(obj)/Image.lzo: $(obj)/Image FORCE
> > > $(obj)/Image.zst: $(obj)/Image FORCE
> > > $(call if_changed,zstd)
> > >
> > > +# Use this to override the compression algorithm
> > > +FIT_COMPRESS ?= gzip
> > > +
> > > +$(obj)/image.fit: $(obj)/Image FORCE
> > > + $(call cmd,fit,$(FIT_COMPRESS))
> >
> >
> >
> > Again, $(FIT_COMPRESS) is not used anywhere.
> >
> >
> > Please fix it to
> >
> > $(call cmd,fit)
> >
> >
> >
> >
> > See your code.
> >
> >
> > cmd_fit = $(MAKE_FIT) -f $@ --arch $(UIMAGE_ARCH) --os linux \
> > --name '$(UIMAGE_NAME)' \
> > --compress $(UIMAGE_COMPRESSION) -k $< \
> > $(<D)/dts
> >
> >
> > cmd_fit does not take any argument.
> >
> >
> > The compression is determined by $(UIMAGE_COMPRESSION).
>
> This references argument 2, which is how it works. I have tested this,
Hah, I missed it, sorry.
You want to use gzip instead of none as the
default compression for the fit image, right?
If so, maybe, you can directly add FIT_COMPRESSION
in scripts/Makefile.lib
Users are still allowed to override it from an
environment variable.
FIT_COMPRESSION ?= gzip
cmd_fit = $(MAKE_FIT) -f $@ --arch $(UIMAGE_ARCH) --os linux \
--name '$(UIMAGE_NAME)' \
--compress $(FIT_COMPRESSION) -k $< \
$(<D)/dts
> for example:
>
> ARCH=arm64 CROSS_COMPILE=... make FIT_COMPRESS=lzma image.fit
>
> I do want to support different algorithms, if possible. Is there a
> better way to do this?
>
> Regards,
> Simon
--
Best Regards
Masahiro Yamada
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