AMD Bulldozer/Jaguar CPUs Will No Longer Advertise RdRand Support Under Linux

[Guest]

nranger - I hear you, I've faced the same kinds of problems with AMD desktop cards as well. I have an R9 390 which is also GCN 1.1 so I know the problems you faced.

Luckily, I splurged and bought a Thinkpad X1 Carbon when it was on sale, so now I have a nice laptop with Intel CPU and GPU and Intel WiFi that Just Works(TM).

[Ardje]

lol, kernel can't produce random numbers without hardware. while patch is correct, you can't use kernel instead of hardware, you have to use some other hardware

I don't know why you are LOLing. How the kernel generates random values has been described clearly. And the kernel is constantly reseeding it's generator with random measurements from the system. Patches to let the kernel's random generator solely rely on RdRand has always been rejected. There have been enough problems with it (also on intel) that nobody really wants to use it.
So just rely on the kernel interface.

[xpue]

AMD FineWine™.

[torsionbar28]

Right in the 'AMD support is excellent for Linux' meme.

It's clear you don't understand how rdrand is used. Also that you haven't read the proposed patch, which clearly states this workaround is for faulty BIOS implementations, not a flaw in the CPU. You'd think that here in 2019, the intel fanboys would have plenty of their own intel CPU hardware flaws to keep them occupied, sheesh.

[pal666]

So just rely on the kernel interface.

do you just rely on kernel interface instead of using sse instructions?
if rdrand is faulty, it will be faulty in kernel. but they are just relying on kernel interface btw - kernel reports rdrand capability, and as kernel stopped reporting it, they stopped using it. exactly as you asked