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=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 AEA11C4338F for ; Thu, 29 Jul 2021 14:24:13 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 76EBC60560 for ; Thu, 29 Jul 2021 14:24:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 76EBC60560 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Reply-To:Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date :Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=6Wu2DsuP+QbuY/253NQo11TjGT/j77idQELDUKuNbFI=; b=emQfbzheudfjzXbcThMNuFcTIe nNsAbX8vzmSr28FQieYjttno165IjqbqJPgcYOAxljl6UxBp2UcrYfiJHrzR82Hgqf9eathe0M1KK fS+hHWuoSltIFigbZv0sdgkoB9oZWW9CnVa1Flt8QDEY5JJt9DStsEZhFgsy0bwJRXIpoRK7vAZ3H j30S17Ej4NEUe/Z2wNv8mL1GwPHF7Lo8LMrmGzF+lPEVxPcKTPscHz5uy2uQIMEUASBxzlGQ8Xlmf LWRIKyjjQNS2vVPLNLLMjG/GeiL/yc1L20piqAdc4E0dWxs7UfF8vM3DwJWUymjC26rgbHNXR5i1C uMCToq0A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m96va-004Vfl-1A; Thu, 29 Jul 2021 14:22:26 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1m96vV-004Vep-G1 for linux-arm-kernel@lists.infradead.org; Thu, 29 Jul 2021 14:22:22 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id A62F0600CD; Thu, 29 Jul 2021 14:22:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627568541; bh=dGJgCD9HBU4P5F9+JMOW0kQ1g0Etx3KrkT/csNNl57c=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TDQ1UhqOcQa1kNQ8TfW19UybYqdMgP5lG2WZlXstrLzAeAycSK5LgZPS56m8dMXl3 haeW2ePQlZ27gJeuDemjtH6e088VrXqPBDMx3XrAL1cJbRW2nXlD50VnrAq9pWdgov QUeAU4b4y9pmzJg5kFUPm/QkYQ1T8gUBjLMiZYYiWXHUeaNQlqNuV9t2x33qjCqN/A 5amf808l1c2BBQxKAfopczc+k3cBS3KghjpXNf1Odk4QorrxrjgmXw8z3IV77yOKvh YKXPbRUZ/6eDEbG3Vqi7qY44BRID6ssngJJTun/Fn5aL/solHmX0Rnw39Xkh4ApnaK oZczgHTX+pfGA== Date: Thu, 29 Jul 2021 15:22:10 +0100 From: Mark Brown To: Sebastian Andrzej Siewior Cc: linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Thomas Gleixner Subject: Re: [PATCH] arm64/sve: Make kernel FPU protection RT friendly Message-ID: <20210729142210.GN4670@sirena.org.uk> References: <20210729105215.2222338-1-bigeasy@linutronix.de> <20210729105215.2222338-3-bigeasy@linutronix.de> MIME-Version: 1.0 In-Reply-To: <20210729105215.2222338-3-bigeasy@linutronix.de> X-Cookie: Vini, vidi, Linux! User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210729_072221_591070_B5284B2B X-CRM114-Status: GOOD ( 10.01 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============1867420289876168205==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============1867420289876168205== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="yOym6oKMddBvWW1X" Content-Disposition: inline --yOym6oKMddBvWW1X Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jul 29, 2021 at 12:52:15PM +0200, Sebastian Andrzej Siewior wrote: > Non RT kernels need to protect FPU against preemption and bottom half > processing. This is achieved by disabling bottom halves via > local_bh_disable() which implictly disables preemption. >=20 > On RT kernels this protection mechanism is not sufficient because > local_bh_disable() does not disable preemption. It serializes bottom half > related processing via a CPU local lock. >=20 > As bottom halves are running always in thread context on RT kernels > disabling preemption is the proper choice as it implicitly prevents bottom > half processing. I think someone sent a very similar looking patch in the past week or two? --yOym6oKMddBvWW1X Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmECuZEACgkQJNaLcl1U h9CBtgf/aBMyaVSxQwBHI/z0Wq7Ahr9a5lsz5e7YtiFtnnNsUGjEZIznJ8Z0qWNp 6SFHsbeiYzCLTAJA07kYvQ6Q92QszPheSU+xCdcxyx5z/5bWdA8ganaJ7Asdl6+0 YYEWdhrw5ZtIFEby2dZZ8es7CoEF+flh3TgenIi/CM4LY65rMUwKD+6pEnyvuzCa ZCDWX9QuRneF7ZSxvkXDeMTbbTvOkM/ql2VPIBth5v1PVDhWVevw9EIfK41v7QYT vHC/aPav9aXpOmTf/ExE+JTFlWTMwrQQPDP6Tpczloc5L4LcAnNxX76vaOsMR6IX 5KEQMp92EVrfgAuH94IH2XGRJ4lDWA== =ucN6 -----END PGP SIGNATURE----- --yOym6oKMddBvWW1X-- --===============1867420289876168205== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============1867420289876168205==--