Messages in this thread | | | Subject | Re: [v6 11/15] arm64/kasan: explicitly zero kasan shadow memory | From | Pasha Tatashin <> | Date | Tue, 8 Aug 2017 08:49:55 -0400 |
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Hi Will,
> Damn, I actually prefer the flag :) > > But actually, if you look at our implementation of vmemmap_populate, then we > have our own version of vmemmap_populate_basepages that terminates at the > pmd level anyway if ARM64_SWAPPER_USES_SECTION_MAPS. If there's resistance > to do this in the core code, then I'd be inclined to replace our > vmemmap_populate implementation in the arm64 code with a single version that > can terminate at either the PMD or the PTE level, and do zeroing if > required. We're already special-casing it, so we don't really lose anything > imo.
Another approach is to create a new mapping interface for kasan only. As what Ard Biesheuvel wrote:
> KASAN uses vmemmap_populate as a convenience: kasan has nothing to do > with vmemmap, but the function already existed and happened to do what > KASAN requires. > > Given that that will no longer be the case, it would be far better to > stop using vmemmap_populate altogether, and clone it into a KASAN > specific version (with an appropriate name) with the zeroing folded > into it.
I agree with this statement, but I think it should not be part of this project.
Pasha
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