Messages in this thread | | | Date | Sun, 5 Mar 2017 01:33:49 +0100 | From | Borislav Petkov <> | Subject | Re: Question Regarding ERMS memcpy |
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On Sat, Mar 04, 2017 at 04:23:17PM -0800, hpa@zytor.com 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."
-- Regards/Gruss, Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --
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