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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3382C52D6F for ; Wed, 21 Aug 2024 12:48:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3FD726B00E6; Wed, 21 Aug 2024 08:48:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3AD1D6B0115; Wed, 21 Aug 2024 08:48:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 24D656B0116; Wed, 21 Aug 2024 08:48:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 043566B00E6 for ; Wed, 21 Aug 2024 08:48:35 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id A20841402DE for ; Wed, 21 Aug 2024 12:48:35 +0000 (UTC) X-FDA: 82476231390.09.6730F80 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf10.hostedemail.com (Postfix) with ESMTP id D99C8C001F for ; Wed, 21 Aug 2024 12:48:32 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=c2vqtqLz; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf10.hostedemail.com: domain of broonie@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=broonie@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1724244448; a=rsa-sha256; cv=none; b=g2yd9j0dBmoO68d9+WKsOxpHz6Pl5F3eIjQDwUd5lt2y96GvWznWk0zhnQKr1IBz7FwHcF aK2jPhl4YOR6/M/NyoYS32fsEDcDZbTkxzuJ3B9tfkoimtJuHrT/aBTKwSHVUAvoUABzjd sJ0ZJB1hEzBakvErh4poxrDizRP6P4M= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=c2vqtqLz; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf10.hostedemail.com: domain of broonie@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=broonie@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1724244448; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=369GC2xOfsQ2Dp/ZCHQm8dV212RSO5ESNv8LhHO1baw=; b=2Ld9LW+ef2JLSIZQvsRY6UGhoKkgNDoSkAaIAFI9x7XJDy9T+WPOK0KtsxqOpojD7M5jXu anYcosxJiVBbXG8s6QF/weGlhahISIQzQ0Fznm0YaGMX1kQSoBBeIOQsEZgJuoGkoOhNb6 KVcBvt6ShM1RTliFcjYCKmwUbPYBi2E= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id E024660FEF; Wed, 21 Aug 2024 12:48:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34586C4AF0C; Wed, 21 Aug 2024 12:48:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1724244511; bh=j9HZBA2/5Wb2g40y9Oti29HTzjGioJbne5mKkeX2ur8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=c2vqtqLzx77yK+jri4pI05ZBvo2YloFCkoCVtCEjRuNnOxfTyJdeVqAID+oks/Got k/MOAywNrA9LkLm2vhxFrX8HojrmEpCpPMFZ8usZAOfEXdFUi9ZJwugyMFj8wDYOpP J1p1m7nAlRo1BJ53vsZ41xGztHqtr9cQpA/9TG6W3AYjgGVSZYvjFqKjCbFotL/+sN WOBnbQJNg1ix3kDwZLLHWgSh5TWlK3ROmZdRmEhC1vOJVT/Udnx4TyTf9FOU8SDCdC IYiUPSkNc7T8xR3pNt74QmD397GNbk0kklwH3BlYq4s8DCTEhzbg4+mFWP0qXvQSXc HGPkV5gyPIOuA== Date: Wed, 21 Aug 2024 13:48:22 +0100 From: Mark Brown To: Catalin Marinas Cc: Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy , Kees Cook , "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Florian Weimer , Christian Brauner , Thiago Jung Bauermann , Ross Burton , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH v10 19/40] arm64/gcs: Context switch GCS state for EL0 Message-ID: <3bc63a7e-0cb7-483b-9054-b52727997b6d@sirena.org.uk> References: <20240801-arm64-gcs-v10-0-699e2bd2190b@kernel.org> <20240801-arm64-gcs-v10-19-699e2bd2190b@kernel.org> <0f6fd3ec-2481-4507-af0e-3cbbb7406b54@sirena.org.uk> <3b316422-7f88-4f5d-a691-eb9209ec4ba9@sirena.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="qtdMReCOgtjtAPvI" Content-Disposition: inline In-Reply-To: X-Cookie: You are false data. X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: D99C8C001F X-Stat-Signature: aiu53p95woz65186iyk9coxtyyj3aenm X-Rspam-User: X-HE-Tag: 1724244512-652767 X-HE-Meta: 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 E3EXnJ2c T+lqhmMYsg0vzGXyV/E4l6TnN4tOmzDWOKhxWwLLcQ6M/tejA3v/ngsu1v5G/gn0jVDQ3SUcvmv57Xt4vpBSfSifdM/E0S2gxF8nEptuUuVeItBRR2F+wAwVHBj03bAJPg/+m0CLpFjFEB0HG/rgXFDEjkaio839OIy6K/vyiunBJT/MUJbvNyubP2tmfqEo8mW9vV9YeMweIdz0kz4hNnYuxsfMiZYm0YxOp0QUO2HEu6I8U5K2XJbxs9TzuZQyPauk3+jb7yy0W0zmD1crGqgpON9C7mSxSHtCY2F1m+yRzjkuZPOoJ9gzDwIB0t9UZ9LG5m2dks0QwQZIX/IWlEHvepa7UrMtIJjhChq7ClCGprfgK+atBicPuGoLrMBcfqtP0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: --qtdMReCOgtjtAPvI Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Aug 21, 2024 at 09:50:22AM +0100, Catalin Marinas wrote: > On Tue, Aug 20, 2024 at 06:56:19PM +0100, Mark Brown wrote: > > I forgot when writing the above that we always allow reads from > > GCSPR_EL0 in order to avoid corner cases for unwinders in the case of > > asynchronous disable. I'd expect that to be cheap to access though. > But then gcs_preserve_current_state() doesn't save the GCSPR_EL0 value > if the shadow stack was disabled. At the subsequent switch to this task, > we write some stale value. True, we should make the disable save the current value. --qtdMReCOgtjtAPvI Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmbF4hUACgkQJNaLcl1U h9DrbQf/SQgnftiL0Tbvv1xffP9U4UoVPIul2GtdtgQHIDIzT1ukcsmQhdRliW8p YkPVH3S3HbTM+Qtdp/kLSqVJHoK9rDDUsUJYlLAIBhC0dxhz6vEeOekbUti1UKFB hdq/nUQDHb0LMufsGWvFir+5WNZkrUMFajAkS8FQ/0RFAA8IXmWgihu6T+Lf1wu2 TVR7gLXkxw51w03S8rD5D4xGzNLF6xXKU50cftHNVPwu8zsPbXCbu1jIpaPVPCXM oWKLc3IOSmG0w3XNoWb7Ki07+H0OmcAbrXvIDK/8FLyyHrcehyy+teM/H/AJqJtt gDCFIXYlvUlLXHmodMUWCk2uNYAYXA== =msk7 -----END PGP SIGNATURE----- --qtdMReCOgtjtAPvI--