https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921
--- Comment #5 from Linus Torvalds <torva...@linux-foundation.org> ---
(In reply to Linus Torvalds from comment #2)
>
> So we could make our workaround option be something like
>
> config GCC_ASM_GOTO_WORKAROUND
> def_bool y
> depends on CC_IS_GCC && GCC_VERSION < 120100
Replying to myself some more, since that kernel side workaround is actually in
two parts: it does the extra empty inline asm as an extra barrier, but it
*also* adds the 'volatile' to the asm with outputs to work around the other gcc
bug.
And that other fix ("Mark asm goto with outputs as volatile") is *not* in
gcc-12.1.0. It has only made it into gcc-13.2.0 (and it's pending in the gcc-12
release branch if I read things right).
I suspect that other bug doesn't affect Sean's kvm case, because the outputs
are always used, but it could affect other kernel code.
So we'd want to have at least gcc-13.2 to be safe.
Hmm.
We could make the "add volatile manually" be the default workaround, though,
since it shouldn't matter.
