defconfig support for CPU_BIG_ENDIAN arm64 kernel

defconfig support for CPU_BIG_ENDIAN arm64 kernel

[Scott Branden]

For arm64 platforms there is only a single defconfig upstreamed.  This 
builds for Little Endian ARM64 platforms.  So...what about Big Endian?

It seems like we need another defconfig with CPU_BIG_ENDIAN to be 
enabled and built in the upstream kernel.  We need this deconfig to test 
that drivers compile in big endian mode and we have an upstream kernel 
image to run on these systems.

I'm hoping the upstreamed kernel is already being built/tested with the 
arm64 big endian compiler.

If not, perhaps the upstream solution is to continue to use the single 
defconfig we have today and start using scripts/kconfig/merge_config.sh 
to add the CPU_BIG_ENDIAN support to generate a big endian defconfig?

Hopefully arm64 is already being compiled and tested for Big Endian and 
I'm missing something?

Regards,
  Scott

defconfig support for CPU_BIG_ENDIAN arm64 kernel

[Arnd Bergmann]

On Monday 23 November 2015 13:58:42 Scott Branden wrote:
> For arm64 platforms there is only a single defconfig upstreamed.  This 
> builds for Little Endian ARM64 platforms.  So...what about Big Endian?
> 
> It seems like we need another defconfig with CPU_BIG_ENDIAN to be 
> enabled and built in the upstream kernel.  We need this deconfig to test 
> that drivers compile in big endian mode and we have an upstream kernel 
> image to run on these systems.
> 
> I'm hoping the upstreamed kernel is already being built/tested with the 
> arm64 big endian compiler.
> 
> If not, perhaps the upstream solution is to continue to use the single 
> defconfig we have today and start using scripts/kconfig/merge_config.sh 
> to add the CPU_BIG_ENDIAN support to generate a big endian defconfig?
> 
> Hopefully arm64 is already being compiled and tested for Big Endian and 
> I'm missing something?

kernelci.org uses Kconfig fragments to build big-endian kernels with
merge-config.sh

We should probably make it a little more straightforward to do this
with mainline kernels. 'make help' already shows 'kvmconfig', 'xenconfig'
and 'tinyconfig' targets for arm64 that use this. Any suggestions how we
should name and integrate big-endian builds?

	Arnd

defconfig support for CPU_BIG_ENDIAN arm64 kernel

[Scott Branden]

Hi Arnd,

On 15-11-23 02:04 PM, Arnd Bergmann wrote:
> On Monday 23 November 2015 13:58:42 Scott Branden wrote:
>> For arm64 platforms there is only a single defconfig upstreamed.  This
>> builds for Little Endian ARM64 platforms.  So...what about Big Endian?
>>
>> It seems like we need another defconfig with CPU_BIG_ENDIAN to be
>> enabled and built in the upstream kernel.  We need this deconfig to test
>> that drivers compile in big endian mode and we have an upstream kernel
>> image to run on these systems.
>>
>> I'm hoping the upstreamed kernel is already being built/tested with the
>> arm64 big endian compiler.
>>
>> If not, perhaps the upstream solution is to continue to use the single
>> defconfig we have today and start using scripts/kconfig/merge_config.sh
>> to add the CPU_BIG_ENDIAN support to generate a big endian defconfig?
>>
>> Hopefully arm64 is already being compiled and tested for Big Endian and
>> I'm missing something?
>
> kernelci.org uses Kconfig fragments to build big-endian kernels with
> merge-config.sh

Glad its already tested!
>
> We should probably make it a little more straightforward to do this
> with mainline kernels. 'make help' already shows 'kvmconfig', 'xenconfig'
> and 'tinyconfig' targets for arm64 that use this. Any suggestions how we
> should name and integrate big-endian builds?

Yes, I would like this ability added to the standard arm64 make 
configuration targets.

To do this we would need to add a new configuration target
"bigendianconfig"
or
"beconfig"  - Update current config to enable big endian support

If we do that - Perhaps the other is necessary as well then?
"littleendianconfig"
or
"leconfig"

I propose the short format "beconfig" and "leconfig" be added.

Thanks,
Scott

>
> 	Arnd
>