From 368f721f71e128cca4398262aafbaf940ea9d83b Mon Sep 17 00:00:00 2001 From: Nicholas Chin Date: Tue, 7 Jan 2025 22:14:32 -0700 Subject: [PATCH] drivers/option: Add CBFS file based option backend MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a new option backend that uses values stored in CBFS files, similar to the SeaBIOS runtime config options stored in files with the etc/ prefix. Options should be stored in CBFS with the option/ prefix. Values can be set using `cbfstool coreboot.rom add-int -n option/ -i `. For simplicity, options should be stored in the COREBOOT (RO) FMAP region, which is the default for cbfstool. This backend is not available in SMM due to CBFS dependencies on vboot functions which are not added to SMM, and thus the fallback will be returned by calls to get_uint_option() in SMM. Tested with QEMU Q35 by setting various options for "sata_mode" and observing the console output for the SATA controller mode during i82801ix_sata initialization. Change-Id: Ifc0439ee42f13f49ae54d4855d1d9333c39b01f5 Signed-off-by: Nicholas Chin Reviewed-on: https://review.coreboot.org/c/coreboot/+/85905 Tested-by: build bot (Jenkins) Reviewed-by: Subrata Banik Reviewed-by: Julius Werner Reviewed-by: Jérémy Compostella --- src/Kconfig | 7 +++++++ src/drivers/option/Makefile.mk | 2 ++ src/drivers/option/cbfs_file_option.c | 27 +++++++++++++++++++++++++++ src/include/option.h | 4 +++- 4 files changed, 39 insertions(+), 1 deletion(-) create mode 100644 src/drivers/option/cbfs_file_option.c diff --git a/src/Kconfig b/src/Kconfig index 55fad952bb..320d6db32c 100644 --- a/src/Kconfig +++ b/src/Kconfig @@ -149,6 +149,7 @@ config UTIL_GENPARSER choice prompt "Option backend to use" + default USE_CBFS_FILE_OPTION_BACKEND if CHROMEOS && PLATFORM_USES_FSP2_0 default USE_MAINBOARD_SPECIFIC_OPTION_BACKEND if HAVE_MAINBOARD_SPECIFIC_OPTION_BACKEND default USE_OPTION_TABLE if NVRAMCUI_SECONDARY_PAYLOAD default USE_UEFI_VARIABLE_STORE if DRIVERS_EFI_VARIABLE_STORE && \ @@ -164,6 +165,12 @@ config USE_OPTION_TABLE Enable this option if coreboot shall read options from the "CMOS" NVRAM instead of using hard-coded values. +config USE_CBFS_FILE_OPTION_BACKEND + bool "Use CBFS files for configuration values" + help + Enable this option if coreboot shall read options from files in CBFS. + Options can be set using `cbfstool add-int -n option/ -i value`. + config USE_UEFI_VARIABLE_STORE bool "Use UEFI variable-store in SPI flash as option backend" depends on DRIVERS_EFI_VARIABLE_STORE diff --git a/src/drivers/option/Makefile.mk b/src/drivers/option/Makefile.mk index 7ca439db78..63ac1baea0 100644 --- a/src/drivers/option/Makefile.mk +++ b/src/drivers/option/Makefile.mk @@ -1,3 +1,5 @@ # SPDX-License-Identifier: GPL-2.0-only ramstage-$(CONFIG_DRIVERS_OPTION_CFR) += cfr.c + +all-$(CONFIG_USE_CBFS_FILE_OPTION_BACKEND) += cbfs_file_option.c diff --git a/src/drivers/option/cbfs_file_option.c b/src/drivers/option/cbfs_file_option.c new file mode 100644 index 0000000000..b87bba8fb9 --- /dev/null +++ b/src/drivers/option/cbfs_file_option.c @@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include +#include +#include + +unsigned int get_uint_option(const char *name, const unsigned int fallback) +{ + size_t size; + uint64_t value; + char full_name[CBFS_METADATA_MAX_SIZE]; + snprintf(full_name, sizeof(full_name), "option/%s", name); + + void *p = cbfs_ro_map(full_name, &size); + if (!p || size < sizeof(value)) { + value = fallback; + } else { + value = le64dec(p); + cbfs_unmap(p); + } + return (unsigned int)value; +} + +enum cb_err set_uint_option(const char *name, unsigned int value) +{ + return CB_ERR_NOT_IMPLEMENTED; +} diff --git a/src/include/option.h b/src/include/option.h index 3a00570064..bee761acfb 100644 --- a/src/include/option.h +++ b/src/include/option.h @@ -7,7 +7,9 @@ void sanitize_cmos(void); -#if CONFIG(OPTION_BACKEND_NONE) +/* The CBFS file option backend cannot be used in SMM due to vboot + * dependencies, which are not added to SMM */ +#if CONFIG(OPTION_BACKEND_NONE) || (CONFIG(USE_CBFS_FILE_OPTION_BACKEND) && ENV_SMM) static inline unsigned int get_uint_option(const char *name, const unsigned int fallback) {