On Thu, Aug 27, 2020 at 1:31 PM Vincenzo Frascino
[off-list ref] wrote:

Hi Andrey,

On 8/14/20 6:27 PM, Andrey Konovalov wrote:

quoted

+config·KASAN_HW_TAGS
+» bool·"Hardware·tag-based·mode"
+» depends·on·HAVE_ARCH_KASAN_HW_TAGS
+» depends·on·SLUB
+» help
+» ··Enables·hardware·tag-based·KASAN·mode.
+
+» ··This·mode·requires·both·Memory·Tagging·Extension·and·Top·Byte·Ignore
+» ··support·by·the·CPU·and·therefore·is·only·supported·for·modern·arm64
+» ··CPUs·(MTE·added·in·ARMv8.5·ISA).
+

I do not thing we should make KASAN_HW_TAGS MTE specific especially because it
is in the common code (e.g. SPARC ADI might want to implement it in future).

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.

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