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arm64: Support async MTE
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Authored by andrew on Mar 19 2026, 4:07 PM.
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Details

Reviewers
manu
Group Reviewers
arm64
Summary

MTE supports a mode where tags are checked asynchronously. When this is
supported and enabled then tag check failures are recorded by setting
the TFSRE0_EL1.TF0 field (for userspace tag faults). This field is then
checked on kernel entry & send userspace a SIGSEGV if no other signals
are being sent.

This allows the tag check to be performed between the memory operation
and the next exception, reducing the overhead. On a tag check failure no
address location is reported so this mode lacks precision of which
memory access failed.

Sponsored by: Arm Ltd

Diff Detail

Repository
rG FreeBSD src repository
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Build Status
Buildable 71540
Build 68423: arc lint + arc unit