tree d4bedf61af0927bf456743246441aefccaef6287
parent b62673c645752a78f649282cfa293e8da09e3bef
author Boyan Karatotev <boyan.karatotev@arm.com> 1737449092 +0000
committer Boyan Karatotev <boyan.karatotev@arm.com> 1740072539 +0000

perf(cpus): inline cpu_rev_var checks

We strive to apply errata as close to reset as possible with as few
things enabled as possible. Importantly, the I-cache will not be
enabled. This means that repeated branches to these tiny functions must
be re-fetched all the way from memory each time which has glacial speed.
Cores are allowed to fetch things ahead of time though as long as
execution is fairly linear. So we can trade a little bit of space (3 to
7 instructions per erratum) to keep things linear and not have to go to
memory.

While we're at it, optimise the the cpu_rev_var_{ls, hs, range}
functions to take up less space. Dropping the moves allows for a bit of
assembly magic that produces the same result in 2 and 3 instructions
respectively.

Change-Id: I51608352f23b2244ea7a99e76c10892d257f12bf
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>