Re: [PATCH v2 5.4 regression fix] x86/boot: Provide memzero_explicit

Ingo Molnar
2019-10-07T15:40:07Z

* Arvind Sankar <nivedita@alum.mit.edu> wrote:

> With the barrier in there, is there any reason to *not* inline the
> function? barrier_data() is an asm statement that tells the compiler
> that the asm uses the memory that was set to zero, thus preventing it
> from removing the memset even if nothing else uses that memory later. A
> more detailed comment is there in compiler-gcc.h. I can't see why it
> wouldn't work even if it were inlined.
>
> If the function can indeed be inlined, we could just make the common
> implementation a macro and avoid duplicating it? As mentioned in another
> mail, we otherwise will likely need another duplicate implementation for
> arch/s390/purgatory as well.

I suspect macro would be justified in this case. Mind sending a v3 patch
to demonstrate how it would all look like?

I'll zap v2 if the macro solution looks better.

Thanks,

Ingo