Re: [RFC PATCH 4/7] kconfig: support new special property shell=

[Arnd Bergmann]

On Tue, Feb 13, 2018 at 2:53 AM, Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
> On 02/12/2018 05:41 PM, Masahiro Yamada wrote:
>> 2018-02-13 8:48 GMT+09:00 Randy Dunlap <rdunlap@xxxxxxxxxxxxx>:
>>> On 02/12/2018 07:24 AM, Kees Cook wrote:
>>>> On Mon, Feb 12, 2018 at 6:39 AM, Masahiro Yamada
>>>> <yamada.masahiro@xxxxxxxxxxxxx> wrote:
>>>
>>>>>> (And in thinking about this, does Kconfig know the true $CC in use?
>>>>>> i.e. the configured cross compiler, etc?)
>>>>>
>>>>> I was thinking of removing CONFIG_CROSS_COMPILE.
>>>>>
>>>>> A user can dynamically change CROSS_COMPILE from
>>>>> "make menuconfig".
>>>>
>>>> Most builds I've seen implement cross compilers as an environment
>>>> variable during all "make" invocations.
>>>
>>> I agree. I think you would break a bunch of build bots if you remove that.
>>
>>
>> For clarification, I suggested to remove CONFIG_CROSS_COMPILE.
>>
>> The following code:
>> https://github.com/torvalds/linux/blob/v4.16-rc1/Makefile#L315
>> https://github.com/torvalds/linux/blob/v4.16-rc1/init/Kconfig#L58
>>
>> I hope build bots are not using this.
>>
>>
>> Passing CROSS_COMPILE via the command line, environment
>> is still supported.
>
> OK, I misunderstood.  That one can go away IMO.

Removing it will break the workflow for some people in a minor way
though. Could we have the top-level Makefile try to detect the
CROSS_COMPILE? Instead of just using CC=gcc as the default,
we could check for ${ARCH}!=`uname -m` and then see if $PATH
contains a ${ARCH}-linux-gcc, ${ARCH}-elf-gcc or ${ARCH}-gcc.

it will need slightly more complexity to deal with architectures
that have different identifiers in linux and gcc, but I think it would
be a nice feature anyway.

     Arnd