ARM branch predictor hardening
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Cover letter [PATCH 0/3] ARM branch predictor hardening
Quoted 7 lines · Marc Zyngier
This small series implements some basic BP hardening by invalidating the BTB on CPUs that are known to be susceptible to aliasing attacks.
These patches are closely modelled against what we do on arm64, although simpler as we can rely on an architected instruction to perform the invalidation.
Quoted 5 lines
The first patch reuses the Cortex-A8 BTB invalidation in
switch_mmand generalises it to be used on all affected CPUs. The second perform the same invalidation on fatal signal delivery. The last one nukes it on guest exit, and results in some major surgery (kudos to Dimitris Papastamos who came up with the magic vector decoding sequence).
So if a Cortex-A8 has bootloder set the IBE bit, and kernel has ARM_ERRATA_430973 enabled, is Cortex-A8 already hardened then?
Regards,
Tony