Re: [PATCH v2] powerpc: Support CMDLINE_EXTEND

Le 02/08/2019 à 00:32, Chris Packham a écrit :

On Thu, 2019-08-01 at 08:14 +0200, Christophe Leroy wrote:

quoted

Le 01/08/2019 à 04:12, Chris Packham a écrit :

quoted

Bring powerpc in line with other architectures that support
extending or
overriding the bootloader provided command line.

The current behaviour is most like CMDLINE_FROM_BOOTLOADER where
the
bootloader command line is preferred but the kernel config can
provide a
fallback so CMDLINE_FROM_BOOTLOADER is the default. CMDLINE_EXTEND
can
be used to append the CMDLINE from the kernel config to the one
provided
by the bootloader.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---
While I'm at it does anyone think it's worth getting rid of the
default CMDLINE
value if CMDLINE_BOOL and maybe CMDLINE_BOOL? Every defconfig in
the kernel
that sets CMDLINE_BOOL=y also sets CMDLINE to something other than
"console=ttyS0,9600 console=tty0 root=/dev/sda2". Removing
CMDLINE_BOOL and
unconditionally setting the default value of CMDLINE to "" would
clean up the
Kconfig even more.

Note
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/co
mmit/?id=cbe46bd4f5104552b612505b73d366f66efc2341
which is already a step forward.

I guess that default is for users selecting this option manually to
get
a first sensitive CMDLINE. But is it really worth it ?

I'm not even sure if it is working as intended right now. Even without
my changes if I use menuconfig and select CMDLINE_BOOL I end up with
CONFIG_CMDLINE="" in the resulting .config.

I guess if the CONFIG_CMDLINE doesn't exist yet, it will get the default value. But if it is already there allthough empty, it will remain empty.
So yes I guess you could just drop it for this reason and the other reasons you said.

Christophe