Re: [PATCH 15/19] csky: Build infrastructure

[Guo Ren]

Hi Arnd,

On Wed, Mar 28, 2018 at 09:40:49AM +0200, Arnd Bergmann wrote:
> Ok, thanks for the clarification. Obviously if they are mutually incompatible,
> there is no point in using a common kernel, so your current version is
> absolutely fine, and this is similar to how we cannot have a common kernel
> between ARMv5, ARMv7-A and ARMv7-M, which are all incompatible
> at the kernel level.
Yes.

> One more question for my understanding: Are the three types of ck8xx
> CPUs mutually incompatible in user space as well, or are the differences
> only for the kernel? For the ARM example, ARMv5 and ARMv7
> fundamentally require separate kernels, but both can run user space
> programs built for ARMv5.

 -mcpu=ck807 app could run on ck807, ck810, ck860.
 -mcpu=ck810 app could run on ck807, ck810, ck860.
 -mcpu=ck860 app only  run on ck860.

They are all incompatible at the kernel level.

Best Regards
 Guo Ren