The documented behaviour for CMDLINE_EXTEND is that the arguments from the bootloader are appended to the built-in kernel command line. This also matches the option parsing behaviour for the EFI stub and early ID register overrides.
Bizarrely, the fdt behaviour is the other way around: appending the built-in command line to the bootloader arguments, resulting in a command-line that doesn't necessarily line-up with the parsing order and definitely doesn't line-up with the documented behaviour. As it turns out, there is a proposal [1] to replace CMDLINE_EXTEND with CMDLINE_PREPEND and CMDLINE_APPEND options which should hopefully make the intended behaviour much clearer. While we wait for those to land, drop CMDLINE_EXTEND for now as there appears to be little enthusiasm for changing the current FDT behaviour. [1] https://lore.kernel.org/lkml/20190319232448.45964-2-danie...@cisco.com/ Cc: Max Uvarov <muva...@gmail.com> Cc: Rob Herring <r...@kernel.org> Cc: Ard Biesheuvel <a...@kernel.org> Cc: Marc Zyngier <m...@kernel.org> Cc: Doug Anderson <diand...@chromium.org> Cc: Tyler Hicks <tyhi...@linux.microsoft.com> Cc: Frank Rowand <frowand.l...@gmail.com> Cc: Catalin Marinas <catalin.mari...@arm.com> Link: https://lore.kernel.org/r/CAL_JsqJX=TCCs7=gg486r9tn4nyscmtclnfqjf9crskkpq-...@mail.gmail.com Signed-off-by: Will Deacon <w...@kernel.org> --- arch/arm64/Kconfig | 6 ------ arch/arm64/kernel/idreg-override.c | 5 +---- 2 files changed, 1 insertion(+), 10 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 1f212b47a48a..f15418332d16 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1855,12 +1855,6 @@ config CMDLINE_FROM_BOOTLOADER the boot loader doesn't provide any, the default kernel command string provided in CMDLINE will be used. -config CMDLINE_EXTEND - bool "Extend bootloader kernel arguments" - help - The command-line arguments provided by the boot loader will be - appended to the default kernel command string. - config CMDLINE_FORCE bool "Always use the default kernel command string" help diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c index cc071712c6f9..83f1c4b92095 100644 --- a/arch/arm64/kernel/idreg-override.c +++ b/arch/arm64/kernel/idreg-override.c @@ -188,11 +188,8 @@ static __init void parse_cmdline(void) { const u8 *prop = get_bootargs_cmdline(); - if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || - IS_ENABLED(CONFIG_CMDLINE_FORCE) || - !prop) { + if (IS_ENABLED(CONFIG_CMDLINE_FORCE) || !prop) __parse_cmdline(CONFIG_CMDLINE, true); - } if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && prop) __parse_cmdline(prop, true); -- 2.30.1.766.gb4fecdf3b7-goog
