From: Adrian Freihofer <[email protected]> With ENV_WRITEABLE_LIST only specific environment variables lisetd in CFG_ENV_FLAGS_LIST_STATIC are read from the u-boot environment storage. All other environment variables are set to default values and are not written back to the storage.
The u-boot environment usually stays for the lifetime of the product. There is no A/B copy mechanism as for the firmware itself. That means that incompatible changes to environment variables in future u-boot versions may lead to serious issues if the old environment is used with a new u-boot version or vice versa. Having this protection in place ensures that only a limited set of environment variables are persisted across u-boot versions. All the macros not listed in CFG_ENV_FLAGS_LIST_STATIC are now part of the u-boot binary which is redundant and immutable. This guarantees that the u-boot version and the default values of these environment variables are always in sync and cannot be changed at runtime. ustate and rastate are not relevant for u-boot itself. ustate is used by swupdate which persists the transaction state in the environment. rastate is a similar variable used by another user space application. Signed-off-by: Adrian Freihofer <[email protected]> Signed-off-by: Heiko Schocher <[email protected]> --- configs/imx8qxp_capricorn.config | 1 + include/configs/capricorn-common.h | 14 ++++++++++++++ 2 files changed, 15 insertions(+) diff --git a/configs/imx8qxp_capricorn.config b/configs/imx8qxp_capricorn.config index 626634cb09c..2bae5b1a862 100644 --- a/configs/imx8qxp_capricorn.config +++ b/configs/imx8qxp_capricorn.config @@ -12,6 +12,7 @@ CONFIG_CUSTOM_SYS_INIT_SP_ADDR=0x80200000 CONFIG_ENV_SIZE=0x2000 CONFIG_ENV_REDUNDANT=y CONFIG_ENV_MMC_EMMC_HW_PARTITION=2 +CONFIG_ENV_WRITEABLE_LIST=y CONFIG_DM_GPIO=y CONFIG_AHAB_BOOT=y diff --git a/include/configs/capricorn-common.h b/include/configs/capricorn-common.h index 7120a44d186..bbacea09aed 100644 --- a/include/configs/capricorn-common.h +++ b/include/configs/capricorn-common.h @@ -38,6 +38,20 @@ #define CFG_EXTRA_ENV_SETTINGS \ AHAB_ENV +#ifdef CONFIG_ENV_WRITEABLE_LIST +#define CFG_ENV_FLAGS_LIST_STATIC \ + "bootcount:dw," \ + "bootdelay:sw," \ + "bootlimit:dw," \ + "ip_method:sw," \ + "partitionset_active:sw," \ + "rastate:dw," \ + "sig_a:sw,sig_b:sw," \ + "target_env:sw," \ + "upgrade_available:dw," \ + "ustate:dw" +#endif + /* Default location for tftp and bootm */ /* On CCP board, USDHC1 is for eMMC */ -- 2.20.1
