Messages in this thread | | | Date | Tue, 8 Aug 2017 13:30:43 +0100 | From | Will Deacon <> | Subject | Re: [v6 11/15] arm64/kasan: explicitly zero kasan shadow memory |
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On Tue, Aug 08, 2017 at 07:49:22AM -0400, Pasha Tatashin wrote: > Hi Will, > > Thank you for looking at this change. What you described was in my previous > iterations of this project. > > See for example here: https://lkml.org/lkml/2017/5/5/369 > > I was asked to remove that flag, and only zero memory in place when needed. > Overall the current approach is better everywhere else in the kernel, but it > adds a little extra code to kasan initialization.
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.
Will
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