From 4924cdb9ace88336cc37506a745ebef210f20767 Mon Sep 17 00:00:00 2001 From: Julius Werner Date: Wed, 16 Nov 2022 17:48:46 -0800 Subject: [PATCH] build: List all Kconfigs in CBFS `config` file, compress it The coreboot build system automatically adds a `config` file to CBFS that lists the exact Kconfig configuration that this image was built with. This is useful to reproduce a build after the fact or to check whether support for a specific feature is enabled in the image. However, the file is currently generated using the `savedefconfig` command to Kconfig, which generates the minimal .config file that is needed to produce the required config in a coreboot build. This is fine for reproduction, but bad when you want to check if a certain config was enabled, since many configs get enabled by default or pulled in through another config's `select` statement and thus don't show up in the defconfig. This patch tries to fix that second use case by instead including the full .config instead. In order to save some space, we can remove all comments (e.g. `# CONFIG_XXX is not set`) from the file, which still makes it easy to test for a specific config (if it's in the file you can extract the right value, if not you can assume it was set to `n`). We can also LZMA compress it since this file is never read by firmware itself and only intended for later re-extraction via cbfstool, which always has LZMA support included. On a sample Trogdor device the existing (uncompressed) `config` file takes up 519 bytes in CBFS, whereas the new (compressed) file after this patch will take up 1832 bytes -- still a small amount that should hopefully not break the bank for anyone. Signed-off-by: Julius Werner Change-Id: I5259ec6f932cdc5780b8843f46dd476da9d19728 Reviewed-on: https://review.coreboot.org/c/coreboot/+/69710 Tested-by: build bot (Jenkins) Reviewed-by: Yu-Ping Wu Reviewed-by: Jakub Czapiga Reviewed-by: Martin Roth --- Makefile.inc | 13 ++++++------- src/Kconfig | 4 ++-- 2 files changed, 8 insertions(+), 9 deletions(-) diff --git a/Makefile.inc b/Makefile.inc index b4c2cdfe92..ef565c2fc9 100644 --- a/Makefile.inc +++ b/Makefile.inc @@ -305,17 +305,15 @@ cbfs-files-processor-nvramtool= \ mv $(2).tmp $(2)) ####################################################################### -# Reduce a .config file to its minimal representation +# Reduce a .config file by removing lines about unset booleans # arg1: input # arg2: output -define cbfs-files-processor-defconfig - $(eval $(2): $(1) $(obj)/build.h $(objutil)/kconfig/conf; \ +define cbfs-files-processor-config + $(eval $(2): $(1) $(obj)/build.h; \ +printf " CREATE $(2) (from $(1))\n"; \ printf "# This image was built using coreboot " > $(2).tmp && \ grep "\" $(obj)/build.h |cut -d\" -f2 >> $(2).tmp && \ - $(MAKE) DOTCONFIG=$(1) DEFCONFIG=$(2).tmp2 savedefconfig && \ - cat $(2).tmp2 >> $(2).tmp && \ - rm -f $(2).tmp2 && \ + sed -e '/^CONFIG/!d' $(1) >> $(2).tmp && \ \mv -f $(2).tmp $(2)) endef @@ -1212,8 +1210,9 @@ vgaroms/seavgabios.bin-file := $(CONFIG_PAYLOAD_VGABIOS_FILE) vgaroms/seavgabios.bin-type := raw cbfs-files-$(CONFIG_INCLUDE_CONFIG_FILE) += config -config-file := $(DOTCONFIG):defconfig +config-file := $(DOTCONFIG):config config-type := raw +config-compression := LZMA cbfs-files-$(CONFIG_INCLUDE_CONFIG_FILE) += revision revision-file := $(obj)/build.h diff --git a/src/Kconfig b/src/Kconfig index f30a1bb683..f16b53c47d 100644 --- a/src/Kconfig +++ b/src/Kconfig @@ -211,9 +211,9 @@ config INCLUDE_CONFIG_FILE Saying Y here will increase the image size by 2-3KB. - You can use the following command to easily list the options: + You can then use cbfstool to extract the config from a final image: - grep -a CONFIG_ coreboot.rom + cbfstool coreboot.rom extract -n config -f Alternatively, you can also use cbfstool to print the image contents (including the raw 'config' item we're looking for).