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 87E3FC4167B for ; Thu, 7 Dec 2023 14:12:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 269536B0081; Thu, 7 Dec 2023 09:12:34 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1F2B86B0088; Thu, 7 Dec 2023 09:12:34 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1080B6B0089; Thu, 7 Dec 2023 09:12:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 03D266B0081 for ; Thu, 7 Dec 2023 09:12:34 -0500 (EST) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id C88BFA0214 for ; Thu, 7 Dec 2023 14:12:33 +0000 (UTC) X-FDA: 81540212586.09.BB58B12 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf15.hostedemail.com (Postfix) with ESMTP id E24BCA0008 for ; Thu, 7 Dec 2023 14:12:31 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=KNjNn79q; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf15.hostedemail.com: domain of broonie@kernel.org designates 145.40.68.75 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=1701958352; 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=+gztOlwLqoxlc6p24w78awa2dpugbjJOPrgLwHsvqxA=; b=CFv9r8PaUhctnwWmtnvINhMD26/7NaVgiXL+tbdwTOFedIkBqIevwKfh6Krs+yF3A6gKZP LNTE2pHCFUiRz+e73VSK4+KOYXpWa7FTPVPiBHM8Ie7cZueF5QgbZo18AnMVpYoxsc8DKS z/GWXA/LagTP1FusJ4TVtWIjaYOtaqY= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=KNjNn79q; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf15.hostedemail.com: domain of broonie@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=broonie@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1701958352; a=rsa-sha256; cv=none; b=1VcuAlOZdnlOS218WTzIM12CdIJrA3F+CPm/7zzaUDbCkZUo+F1z68V3Fxyl56y4asoCmH 5sbPNa+04a5QQ6KmTN9TYMHS6kbYHrUKDtyIH7lSmHB/u9j80YU/4XDr1nNJDun8thWRjY dQkegLu4bxFWAH1VnFJQJn8GmE37q5U= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by ams.source.kernel.org (Postfix) with ESMTP id 645CFB8285B; Thu, 7 Dec 2023 14:12:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B982C433CA; Thu, 7 Dec 2023 14:12:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701958349; bh=47UZfvnQWDEJSOeupCYwAYrzuYtNC/T8g7iT65OoBZU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KNjNn79q5qw9TWzhiTTP83A72DjqspeTkbwfxzoFnhtiod+ean4s/g2ZihwzwXDAU Am57C5Ozpebi7RrIDin2lfTxnQxnd/g1SJoTl2stCv7gjEib8S29onQm4DWkSwfzAZ zQi1z8Fa3bGDCUGc8ZtXlmlIVQ6Xi6yNJgaAYtgdyVUXKyIp8aiTF0U1YOWvQahFHS ovxFQg0P0owLouv5ZAp97Cl/VvE9siUPJngtZBoqORuYrfG2l/L7z/ZrGnG0gD2Q4f uSh67mCPQywqM40/rxG+J9b+1jRbCMjSIyBubfR+IcM6KHPn1/BRu4XSAbS+A0laFC Gp0YR7Yh9D9NQ== Date: Thu, 7 Dec 2023 14:12:23 +0000 From: Mark Brown To: Catalin Marinas Cc: Joey Gouly , linux-arm-kernel@lists.infradead.org, akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com, dave.hansen@linux.intel.com, maz@kernel.org, oliver.upton@linux.dev, shuah@kernel.org, will@kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, James Morse , Suzuki K Poulose , Zenghui Yu Subject: Re: [PATCH v3 05/25] arm64: context switch POR_EL0 register Message-ID: <6ff480e3-e2d4-472a-ba6f-4037e438f69b@sirena.org.uk> References: <20231124163510.1835740-1-joey.gouly@arm.com> <20231124163510.1835740-6-joey.gouly@arm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="tFLJkYHdpJA4U9vc" Content-Disposition: inline In-Reply-To: X-Cookie: Two is company, three is an orgy. X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: E24BCA0008 X-Stat-Signature: 5egjiq1hxdmbi5cj66zbtcaf3hgd66fq X-HE-Tag: 1701958351-256372 X-HE-Meta: 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 3MsW5QxB qVuOgmBYvo84zzG0T3xts8WH7ri5pwU7QH55+L5Fk8zSvtFNpyy+0PvCfO2Qyjq03O50nKUcpHgqGkW4IjQzWkFuwOE2YhSVGZW6V+5KdBU3Tg0vkosEsHvEbudatPP5u4ERAoA2D27jSfRq6p0O23NzF7fiwb3ZDNL0cMHOOYYkNj6y7KuKFY18DJnCsL5/R7m53UrwmlJTPA+gVj7Ij1H1CxDHIYnxPDW289vtosVpH0X2pgeZB9i8z5pkgr/9jVuN+ZOcTMIK76SowU/UMZzMiDk6QS+dWxx9kpbyJehSaYBE= 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: --tFLJkYHdpJA4U9vc Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, Dec 07, 2023 at 01:55:31PM +0000, Catalin Marinas wrote: > On Sat, Nov 25, 2023 at 12:02:49PM +0000, Mark Brown wrote: > > On Fri, Nov 24, 2023 at 04:34:50PM +0000, Joey Gouly wrote: > > > +static void flush_poe(void) > > > +{ > > > + if (system_supports_poe()) > > > + write_sysreg_s(POR_EL0_INIT, SYS_POR_EL0); > > > +} > > Here we have no isb()... > My immediate thought was that we'd not care about the ISB here since > we'll have an ERET before getting to EL0. However, we may have some > LDTR/STTR populating the new process args page on exec which may, in > theory, pick up a stale POR_EL0. Yeah, it was a combination of the inconsistency and the lack of clarity over there being a path which could potentially use POR_EL0 before ERET. We at least probably need some comments with regard to the requirements here. --tFLJkYHdpJA4U9vc Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmVx0sYACgkQJNaLcl1U h9AZCgf/X0uy8/6EiE75lAKZoYXgFKyGs21xpo+KNf8OlxnW1Cmwd9pWCniE0DGV /4Knlc88paXTUnUA8ufobkjiQdj+R2nYJUnW62qD/SfOULo8As//rlpui0NgjfYO 2e2UKWEJ0cHFdSGifE0R4DF3qmQFo5K73m7ywedSo1IMrbM6EIR6qBTOe3mnOIcu ofI81TpLR6gKiz0hA2uWNITQQK8VNG0Czuvi6QaIVOKnADLbPFP5orAZDEdt4t06 Qa13Ok13tFqqUSxGnsHFnCLRvRILPy2L6ecupywOUsgtMIj3kkfTi4uMRs4EPcMx 6eViRFXbIAXNsGbjwlE1t4vNBPLbBQ== =nEdy -----END PGP SIGNATURE----- --tFLJkYHdpJA4U9vc--