From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83C06C47404 for ; Wed, 9 Oct 2019 08:02:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5DD11206B6 for ; Wed, 9 Oct 2019 08:02:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727766AbfJIICo (ORCPT ); Wed, 9 Oct 2019 04:02:44 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:43187 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725440AbfJIICn (ORCPT ); Wed, 9 Oct 2019 04:02:43 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id 66B758032F; Wed, 9 Oct 2019 10:02:26 +0200 (CEST) Date: Wed, 9 Oct 2019 10:02:40 +0200 From: Pavel Machek To: David Laight Cc: "Theodore Y. Ts'o" , Linus Torvalds , Thomas Gleixner , "Ahmed S. Darwish" , LKML , Nicholas Mc Guire , the arch/x86 maintainers , Andy Lutomirski , Kees Cook Subject: Re: x86/random: Speculation to the rescue Message-ID: <20191009080240.GA11561@amd> References: <20191006114129.GD24605@amd> <20191006173501.GA31243@amd> <20191006182103.GA2394@amd> <20191007114734.GA6104@mit.edu> <20191007221817.GA4027@amd> <4748b43e6b00415fb21c1a127a835e87@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="+QahgC5+KEYLbs62" Content-Disposition: inline In-Reply-To: <4748b43e6b00415fb21c1a127a835e87@AcuMS.aculab.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --+QahgC5+KEYLbs62 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > > I have many systems including SoC here, but technology needed for NAND > > flash is different from technology for CPU, so these parts do _not_ > > share a silicon die. They do not even share same package. (Also RTC > > tends to be on separate chip, connected using i2c). >=20 > NAND flash requires ECC so is likely to be async. > But I2C is clocked from the cpu end - so is fixed. RTC i2c may be clocked from the CPU end, but the time source needs to work when machine is off, so that has a separate crystal for timekeeping. > Also an embedded system could be booting off a large serial EEPROM. > These have fixed timings and are clocked from the cpu end. Have you seen such system running Linux? Best regards, Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --+QahgC5+KEYLbs62 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAl2dlCAACgkQMOfwapXb+vKhEwCeOJiJPIsQBqYclwYrDh8xUdYO 9+cAoI0TgFDfubmPNTzSK/Ib7YMBoqtr =SfmC -----END PGP SIGNATURE----- --+QahgC5+KEYLbs62--