rdrand generated with march=winchip-c6 in systemd-241

tedheadster tedheadster@gmail.com
Tue May 7 15:08:00 GMT 2019


On Tue, May 7, 2019 at 10:55 AM Jeffrey Walton <noloader@gmail.com> wrote:
>
> As far as I know the instruction is only defined for Intel, AMD and
> Hyogen cpus. See, for example,
> https://github.com/weidai11/cryptopp/blob/master/cpu.cpp#L380.
>

Jeff,
  I think you missed my point. The rdrand instruction is _not_
supported on this old hardware at all. The code should detect that and
avoid using it.

So the problem is that cpuid is either 1) incorrectly reporting that
it is supported or 2) the cpuid detection code is wrong.

- Matthew



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