On 2019-10-11 16:39, Marc Gonzalez wrote:
On 11/10/2019 12:50, Mark Rutland wrote:
Before we make any changes, we need to check whether we do actually
handle this variation in a safe way, and we need to consider what this
means w.r.t. late CPU hotplug.
Even if we can handle variation at boot time, once we've determined
the
set of system-wide features we cannot allow those to regress, and I
believe we'll need new code to enforce that. I don't think it's
sufficient to mark these as NONSTRICT, though we might do that with
other changes.
We shouldn't look at the part number at all here. We care about
variation across CPUs regardless of whether this is big.LITTLE or some
variation in tie-offs, etc.
See also the "Unexpected variation in SYS_ID_AA64MMFR0_EL1" thread
from a year ago: (that was on msm8998)
https://www.spinics.net/lists/arm-kernel/msg691242.html
I think, it was fixed by commit: 5717fe5ab38f ("arm64: cpufeature: Don't
treat granule sizes as strict")
Thanks,
Sai
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