Re: meltdown

[maya%netbsd.org@localhost]

On Sat, Jan 06, 2018 at 01:41:38AM -0500, Michael wrote:
> R10k had all sorts of weirdo speculative execution related problems
> ( see hardware workarounds in the O2 ), and I doubt it's the first to
> implement it.

Loongson-2 had an issue where from branch prediction it would prefetch
instructions from the I/O area and deadlock.

This happened in normal usage so we build the kernel with a binutils
flag to output different jumps and flush the BTB on kernel entry.*

I wouldn't count on MIPS CPUs to hold under the same level of scrutiny
as x86 CPUs, luckily they're pretty obscure (and most probably aren't
speculative).

* https://sourceware.org/ml/binutils/2009-11/msg00387.html