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.


Cc: Max Uvarov <>
Cc: Rob Herring <>
Cc: Ard Biesheuvel <>
Cc: Marc Zyngier <>
Cc: Doug Anderson <>
Cc: Tyler Hicks <>
Cc: Frank Rowand <>
Cc: Catalin Marinas <>
Signed-off-by: Will Deacon <>
2 files changed