Re: [RFC] Get rid of SUBARCH

David Daney
2013-08-22T20:55:25Z

On 08/22/2013 01:41 PM, Rob Landley wrote:
> On 08/22/2013 07:58:26 AM, Geert Uytterhoeven wrote:
>> On Wed, Aug 21, 2013 at 9:51 PM, Sam Ravnborg <sam@ravnborg.org> wrote:
>> >> > The series touches also m68k, sh, mips and unicore32.
>> >> > These architectures magically select a cross compiler if ARCH !=
>> SUBARCH.
>> >> > Do really need that behavior?
>> >>
>> >> This does remove functionality.
>> >> It allows to build a kernel using e.g. "make ARCH=m68k".
>> >>
>> >> Perhaps this can be moved to generic code? Most (not all!)
>> cross-toolchains
>> >> are called $ARCH-{unknown-,}linux{,-gnu}.
>> >> Exceptions are e.g. am33_2.0-linux and bfin-uclinux.
>> >
>> > Today you can specify CROSS_COMPILE in Kconfig.
>> > With this we should be able to remove these hacks.
>>
>> The correct CROSS_COMPILE value depends on the host environment, not
>> on the target configuration.
>
> Actually it depends on _both_.
>

I think the important issue is not the exact dependencies of the value
of CROSS_COMPILE, but rather that it varies enough that automatically
choosing a value based on SUBARCH often gives the wrong result.

Removing SUBARCH and setting CROSS_COMPILE either from the make command
line (or environment) or the config file, is a good idea because it
simplifies the build system, makes things clearer, and yields more
predictable results.

David Daney