Re: [PATCH v8 2/2] arm64: boot: Support Flat Image Tree

Hi Masahiro,

On Fri, 1 Dec 2023 at 10:30, Masahiro Yamada masahiroy@kernel.org wrote:

On Fri, Dec 1, 2023 at 5:34 AM Simon Glass sjg@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@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@chromium.org +L: linux-arm-kernel@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@arm.com M: Will Deacon will@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, 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