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charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 019E11004EF40 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Aug 27, 2020 at 1:31 PM Vincenzo Frascino wrote: > > Hi Andrey, > > On 8/14/20 6:27 PM, Andrey Konovalov wrote: > > +config=C2=B7KASAN_HW_TAGS > > +=C2=BB bool=C2=B7"Hardware=C2=B7tag-based=C2=B7mode" > > +=C2=BB depends=C2=B7on=C2=B7HAVE_ARCH_KASAN_HW_TAGS > > +=C2=BB depends=C2=B7on=C2=B7SLUB > > +=C2=BB help > > +=C2=BB =C2=B7=C2=B7Enables=C2=B7hardware=C2=B7tag-based=C2=B7KASAN=C2= =B7mode. > > + > > +=C2=BB =C2=B7=C2=B7This=C2=B7mode=C2=B7requires=C2=B7both=C2=B7Memory= =C2=B7Tagging=C2=B7Extension=C2=B7and=C2=B7Top=C2=B7Byte=C2=B7Ignore > > +=C2=BB =C2=B7=C2=B7support=C2=B7by=C2=B7the=C2=B7CPU=C2=B7and=C2=B7the= refore=C2=B7is=C2=B7only=C2=B7supported=C2=B7for=C2=B7modern=C2=B7arm64 > > +=C2=BB =C2=B7=C2=B7CPUs=C2=B7(MTE=C2=B7added=C2=B7in=C2=B7ARMv8.5=C2= =B7ISA). > > + > > I do not thing we should make KASAN_HW_TAGS MTE specific especially becau= se it > is in the common code (e.g. SPARC ADI might want to implement it in futur= e). > > Probably would be better to provide some indirection in the generic code = an > implement the MTE backend entirely in arch code. > > Thoughts? I think we can reword the help text to say that it enables tag-based KASAN mode that is backed by the hardware in general, and mention that this is currently only implemented for arm64 through MTE. I don't think it makes sense to provide a common arch interface at this point to keep the code simpler. We can do that when (and if) another hardware backend is added.