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From: Jonathan Wakely <jwakely.gcc@gmail.com>
Date: Mon, 4 Oct 2021 10:24:51 +0100
Message-ID: <CAH6eHdTMfY=_hcFRm1A87dZW85K34QTO_txq9t5C7JYtTL-C=Q@mail.gmail.com>
Subject: Re: About amd ryzen 3000 bugs of rdseed and rdrand?
To: unlvsur unlvsur <unlvsur@live.com>
Cc: "unlvsur unlvsur via Libstdc++" <libstdc++@gcc.gnu.org>
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On Mon, 4 Oct 2021 at 09:50, unlvsur unlvsur via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> My computer used to always return -1 for rdseed and rdrand for ryzen 3000.
>
> AMD Ryzen 3000 series CPUs can't do Random on boot causing Boot Failure on newer Linux distributions - LinuxReviews<https://linuxreviews.org/AMD_Ryzen_3000_series_CPUs_can%27t_do_Random_on_boot_causing_Boot_Failure_on_newer_Linux_distributions>
>
> [PATCH] x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h (kernel.org)<https://lore.kernel.org/all/776cb5c2d33e7fd0d2893904724c0e52b394f24a.1565817448.git.thomas.lendacky@amd.com/T/#u>
>
> Libstdc++ uses rdseed and rdrand internally. Does it contain the rdseed bugs on ryzen 3000 cpu?


See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100444