On Wed, Feb 14, 2018 at 11:06 AM, Laura Abbott <labbott@xxxxxxxxxx> wrote: > fixed. Modules yes are not fully protected. The conclusion from past > experience has been that we cannot safely break down larger page sizes > at runtime like x86 does. We could theoretically > add support for fixing up the alias if PAGE_POISONING is enabled but > I don't know who would actually use that in production. Performance > is very poor at that point. XPFO forces 4K pages on the physmap[1] for similar reasons. I have no doubt about performance changes, but I'd be curious to see real numbers. Did anyone do benchmarks on just the huge/4K change? (Without also the XPFO overhead?) If this, XPFO, and PAGE_POISONING all need it, I think we have to start a closer investigation. :) -Kees [1] http://www.openwall.com/lists/kernel-hardening/2017/09/07/13 -- Kees Cook Pixel Security -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
