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Donenfeld" Cc: Borislav Petkov , Gregory Price , x86@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org, mario.limonciello@amd.com, riel@surriel.com, yazen.ghannam@amd.com, me@mixaill.net, kai.huang@intel.com, sandipan.das@amd.com, darwi@linutronix.de, stable@vger.kernel.org Subject: Re: [PATCH v2] x86/amd: Disable RDSEED on AMD Zen5 because of an error. Message-ID: <176216536464.37138.975167391934381427@copycat> User-Agent: Dodo Date: Mon, 03 Nov 2025 02:22:44 -0800 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; protocol="application/pgp-signature"; micalg="pgp-sha512"; boundary="===============5056424951694076744==" --===============5056424951694076744== Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit On Sun 19 Oct 2025 05:03:25 PM , Jason A. Donenfeld wrote: > On Sun, Oct 19, 2025 at 05:00:27PM +0200, Borislav Petkov wrote: > > On Sun, Oct 19, 2025 at 04:46:06PM +0200, Jason A. Donenfeld wrote: > > > While your team is checking into this, I'd be most interested to know > > > one way or the other whether this affects RDRAND too. > > > > No it doesn't, AFAIK. The only one affected is the 32-bit or 16-bit dest > > operand version of RDSEED. Again, AFAIK. > > Oh good. So on 64-bit kernels, the impact to random.c is zilch. > > Jason > Although apparently, the patch does break userspace for any distribution building packages with -march=znver4 - Christopher --===============5056424951694076744== Content-Type: application/pgp-signature Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="signature.asc" MIME-Version: 1.0 -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEdiLr51NrDwQ29PFjjWyYR59K3nEFAmkIgnQACgkQjWyYR59K 3nGg5Q/9HwqTQmyZmJmlaNOajSOMdy/ktzMmuis4X1c14Ri+P9E1uD9h95jOp9Ks TNvPhe7haYL5/5yhP9chuuZT8Skd0aECw2wxmmZ1Ah2qoUQpY6jbYSG8KAaoWH5C ujX/xZaYSqfpgk37dlaPTE8PA2cq+x1AJOlEZn4Re3sGUadU6qYMG7S+BjvLAI4h IprXvD45cjDv5AnisZYQEq0KpM+wYfHrOSuHEkf3q+rFDGO7ityuKtXzuIfH/skZ 70/xw5fZ5Dm0fhj8j5CSy6BLPu8rLl5cirPnPYY02nVDzHBeWS3YTHtOSRSMDzJ6 7spzj4hzrk1xGLDtCQdyqGJlgHF1/w88SG+UD9BkIHOJWcnpDSKcqBEy8hW66UQJ j5eml8leqPC1Qk/QwDFmP8LuRa6RLMJZuSLIB3LahdCyRrcxy3Trf7aNmuRTb5ic t9i3D6ltVNuS2GJ1XVJBdk1cpH8lwVCo+9Fn0KOkA5YhcWCOkxOrKBMxSitCmeBY JdOB+nC5gzqLSS0RsvTt6nda49hOjQWS9AdK+hAOPzZFp9mP3QytfUmJwAT6L+XN 3wZolRgLH4e/n0XoxvqOYWdoDviEysDjIyRMxnS908sDk+g8pR9cbPTBxP+m8abQ +d8setlnsWwaMxbcD1x1vqGnb26GeXMLRva2qw7eUv98dxIN2V0= =pAL5 -----END PGP SIGNATURE----- --===============5056424951694076744==--