Re: [PATCH v2] arch: Kconfig: Let all little endian architectures define CPU_LITTLE_ENDIAN explicitly

Re: [PATCH v2] arch: Kconfig: Let all little endian architectures define CPU_LITTLE_ENDIAN explicitly

[Geert Uytterhoeven]

CC kbuild

On Wed, Aug 13, 2014 at 12:48 AM, Chen Gang <gang.chen.5i5j@gmail.com> wrote:
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index c49a775..0510a5d 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -199,6 +199,11 @@ config NEED_DMA_MAP_STATE
>  config ARCH_SUPPORTS_UPROBES
>         def_bool y
>
> +config CPU_LITTLE_ENDIAN
> +       depends on !CPU_BIG_ENDIAN
> +       def_bool y
> +
> +
>  config ARCH_HAS_DMA_SET_COHERENT_MASK
>         bool

As this is a common symbol, and replicated for all affected architectures,
I'm wondering if we should have the "config CPU_LITTLE_ENDIAN" in
common Kconfig code instead, and make the individual architectures do a
"select CPU_LITTLE_ENDIAN"?

Also we could have "config CPU_BIG_ENDIAN", too, and error out
if none or both are selected (can Kconfig error out?).

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v2] arch: Kconfig: Let all little endian architectures define CPU_LITTLE_ENDIAN explicitly

[Chen Gang]

On 8/13/14 16:03, Geert Uytterhoeven wrote:
> CC kbuild
> 
> On Wed, Aug 13, 2014 at 12:48 AM, Chen Gang <gang.chen.5i5j@gmail.com> wrote:
>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>> index c49a775..0510a5d 100644
>> --- a/arch/arm/Kconfig
>> +++ b/arch/arm/Kconfig
>> @@ -199,6 +199,11 @@ config NEED_DMA_MAP_STATE
>>  config ARCH_SUPPORTS_UPROBES
>>         def_bool y
>>
>> +config CPU_LITTLE_ENDIAN
>> +       depends on !CPU_BIG_ENDIAN
>> +       def_bool y
>> +
>> +
>>  config ARCH_HAS_DMA_SET_COHERENT_MASK
>>         bool
> 
> As this is a common symbol, and replicated for all affected architectures,
> I'm wondering if we should have the "config CPU_LITTLE_ENDIAN" in
> common Kconfig code instead, and make the individual architectures do a
> "select CPU_LITTLE_ENDIAN"?
> 

That sounds a good idea to me.

> Also we could have "config CPU_BIG_ENDIAN", too, and error out
> if none or both are selected (can Kconfig error out?).
> 

It is a good idea to me, welcome any members ideas, especially Kbuild
members' ideas, suggestions or completions.


Thanks.
-- 
Chen Gang

Open, share, and attitude like air, water, and life which God blessed

Re: [PATCH v2] arch: Kconfig: Let all little endian architectures define CPU_LITTLE_ENDIAN explicitly

[Michal Marek]

Dne 13.8.2014 10:03, Geert Uytterhoeven napsal(a):
> CC kbuild
> 
> On Wed, Aug 13, 2014 at 12:48 AM, Chen Gang <gang.chen.5i5j@gmail.com> wrote:
>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>> index c49a775..0510a5d 100644
>> --- a/arch/arm/Kconfig
>> +++ b/arch/arm/Kconfig
>> @@ -199,6 +199,11 @@ config NEED_DMA_MAP_STATE
>>  config ARCH_SUPPORTS_UPROBES
>>         def_bool y
>>
>> +config CPU_LITTLE_ENDIAN
>> +       depends on !CPU_BIG_ENDIAN
>> +       def_bool y
>> +
>> +
>>  config ARCH_HAS_DMA_SET_COHERENT_MASK
>>         bool
> 
> As this is a common symbol, and replicated for all affected architectures,
> I'm wondering if we should have the "config CPU_LITTLE_ENDIAN" in
> common Kconfig code instead, and make the individual architectures do a
> "select CPU_LITTLE_ENDIAN"?

Yes!


> Also we could have "config CPU_BIG_ENDIAN", too, and error out
> if none or both are selected (can Kconfig error out?).

We can error out in the Makefile, if there is consensus that we should
be doing so.

Michal

Re: [PATCH v2] arch: Kconfig: Let all little endian architectures define CPU_LITTLE_ENDIAN explicitly

[Chen Gang]

On 8/22/14 19:09, Michal Marek wrote:
> Dne 13.8.2014 10:03, Geert Uytterhoeven napsal(a):
>> CC kbuild
>>
>> On Wed, Aug 13, 2014 at 12:48 AM, Chen Gang <gang.chen.5i5j@gmail.com> wrote:
>>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>>> index c49a775..0510a5d 100644
>>> --- a/arch/arm/Kconfig
>>> +++ b/arch/arm/Kconfig
>>> @@ -199,6 +199,11 @@ config NEED_DMA_MAP_STATE
>>>  config ARCH_SUPPORTS_UPROBES
>>>         def_bool y
>>>
>>> +config CPU_LITTLE_ENDIAN
>>> +       depends on !CPU_BIG_ENDIAN
>>> +       def_bool y
>>> +
>>> +
>>>  config ARCH_HAS_DMA_SET_COHERENT_MASK
>>>         bool
>>
>> As this is a common symbol, and replicated for all affected architectures,
>> I'm wondering if we should have the "config CPU_LITTLE_ENDIAN" in
>> common Kconfig code instead, and make the individual architectures do a
>> "select CPU_LITTLE_ENDIAN"?
> 
> Yes!
> 
> 
>> Also we could have "config CPU_BIG_ENDIAN", too, and error out
>> if none or both are selected (can Kconfig error out?).
> 
> We can error out in the Makefile, if there is consensus that we should
> be doing so.
> 

OK, thanks. I have sent patch v3 for it, and did not check related error
in Kconfig files.

Please check the related patches (excuse me, I send the patch v3 only
according to "scripts/maintainers.pl", maybe not cc to you explicitly).


Thanks.
-- 
Chen Gang

Open, share, and attitude like air, water, and life which God blessed