Re: Question Regarding ERMS memcpy

[Borislav Petkov]

On Sat, Mar 04, 2017 at 04:23:17PM -0800, hpa@xxxxxxxxx wrote:
> What are the compilation flags? It may be that gcc still does TRT
> depending on this call site. I'd check what gcc6 or 7 generates,
> though.

Well, I don't think that matters: if you're building a kernel on one
machine to boot on another machine, the compiler can't know at build
time what the best MOVS* variant would be for the target machine. That's
why we're doing the alternatives patching at *boot* time.

However, if the size is small enough, the CALL/patch overhead would be
definitely too much.

Hmm, I wish we were able to say, "let gcc decide for small sizes and let
us do the patching for larger ones."

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Regards/Gruss,
    Boris.

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