Re: Re: [PATCH 5.4~6.6] MIPS: Probe toolchain support of -msym32

From: Maciej W. Rozycki
Date: Fri Jan 03 2025 - 00:49:38 EST


On Fri, 3 Jan 2025, WangYuli wrote:

> Are you suggesting that a commit from v6.8 reintroduced a regression that
> was fixed in v6.6?

Correct.

> If so, we should address this issue in the mainline first before backporting.

I do not disagree.

> As a general rule, we avoid introducing out-of-tree commits to linux-stable
> except for reverts.

Understood.

> For this patch, merging it into linux-stable is crucial, as it would prevent
> certain configurations like loongson3_defconfig from building the kernel with
> clang.

Conversely I don't think it's acceptable for -stable to merge a change
that replaces one known bug with another; it violates our rule #2:

- It must be obviously correct and tested.

If you care about support for building with Clang, then please either fix
your fix or fix the compiler to handle `-msym32' or an equivalent option
(which seems a good idea for n64 MIPS performance anyway -- you're wasting
a lot of cycles to explicitly put the sign-extension of bit 31 into the
high order 32 bits where the CPU architecture does it for you already).
And only then offer a backport of whatever you feel is needed to -stable.

Maciej