Re: [PATCH 1/2] MIPS: Allow MIPS32R2 kernel to run on P5600 and M5150

From: Jiaxun Yang
Date: Tue May 30 2023 - 09:10:23 EST

> 2023年5月30日 13:16,Maciej W. Rozycki <macro@xxxxxxxxxxx> 写道:
> On Tue, 30 May 2023, Jiaxun Yang wrote:
>>> Sure, but this change is not needed for it. You just need to declare
>>> which ISA revisions your platform supports and leave `__get_cpu_type'
>>> alone. It has worked like that for a decade now.
>> I’m afraid it won’t work as you expected.
>> Actually I ran into a problem that `case CPU_P5600` in c-r4k.c is optimised out
>> by compiler, because the codepath is marked as unreachable.
> Maybe there's a bug elsewhere then. Send me your .config and I'll try to
> reproduce it.

Ok I see the problem, after applying patch 2 the issue is gone.
So actually only patch 2 is necessary.

The unreachable mark here leads gcc to generate some confusing code
and I misread it.

Sorry for the noise.

- Jiaxun

> Maciej