Commit cae118b6 authored by Will Deacon's avatar Will Deacon
Browse files

arm64: Drop support for CMDLINE_EXTEND 

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-danielwa@cisco.com/

Cc: Max Uvarov <muvarov@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Doug Anderson <dianders@chromium.org>
Cc: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/CAL_JsqJX=TCCs7=gg486r9TN4NYscMTCLNfqJF9crskKPq-bTg@mail.gmail.com
Link: https://lore.kernel.org/r/20210303134927.18975-3-will@kernel.org


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent df304c2d

arch/arm64/Kconfig

+0 −6
Original line number Diff line number Diff line
@@ -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

arch/arm64/kernel/idreg-override.c

+1 −4
Original line number Diff line number Diff line
@@ -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);