[PATCH v2] aarch64: Add MTE mode tunable

[Yury Khrustalev]

On Thu, Sep 10, 2026 at 11:30:01AM -0300, Adhemerval Zanella Netto wrote:
> 
> On 07/09/26 11:02, Yury Khrustalev wrote:
> > Add tunable glibc.cpu.mtemode for selecting tag checking fault mode
> > for Memory Tagging Extension (MTE): disabled, enabled, sync, or async.
> > Default is disabled.
> > 
> > ---
> > Passes regression in aarch64. OK for trunk?
> > 
> > Please note that this patch does not include support for MTE binary
> > marking as there is no intention to implement it at this stage.
> > However, this patch is designed to support such an extension in the
> > future.
> > 
> > Relevant discussion:
> > https://inbox.sourceware.org/libc-alpha/ansmVLinBE86-SZ4@arm.com/
> > 
> > Base commit: fe03757f67
> > 
> > Changes in v2:
> >  - Don't add the 'mte' property to the cpu_features struct.
> >  - Define bool variable for MTE for ifunc resolvers based on
> >    the MTE mode value.
> >  - v1: https://inbox.sourceware.org/libc-alpha/20260904094800.1810189-1-yury.khrustalev@arm.com/
> 
> It is not clear to me why add this support without any MTE usage within
> glibc. All these MTE enablement can done by the application itself, if
> it requires so (like a MTE aware malloc).
> 
> I think this feature should added along the MTE malloc you seems to be
> working on.

One step at a time. Just avoiding long patch series that are difficult
to review and maintain. This change is essential ground work and is
required to unblock work on a couple of other things. If we keep it
attached to them, it creates unnecessary overhead of rebasing and testing
overlapping changes.

Thanks,
Yury