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 2E159E6F08E for ; Fri, 1 Nov 2024 22:39:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 537E36B00A0; Fri, 1 Nov 2024 18:39:26 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4C0EF6B00A1; Fri, 1 Nov 2024 18:39:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 360D96B00A2; Fri, 1 Nov 2024 18:39:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 181766B00A0 for ; Fri, 1 Nov 2024 18:39:26 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 91076802A2 for ; Fri, 1 Nov 2024 22:39:25 +0000 (UTC) X-FDA: 82738992462.01.CA95A9B Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf22.hostedemail.com (Postfix) with ESMTP id 4414DC000F for ; Fri, 1 Nov 2024 22:38:48 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=LEhrLwqB; spf=pass (imf22.hostedemail.com: domain of broonie@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=broonie@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1730500718; 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=JkmskpWLroWyTPtf1p/0xaay+Zwr1MUY5lzV+zGUd1c=; b=hb7H86dxPgtFz5ui7PiUwuPkY2d5D4uzhy6oFfWki+VmoPa4wMpnDansRJJtmeLHwCCGp1 V3YUJuro0/L5hjQNHChMBcF7u694l4ATpcuyKAmttMjRROvb/2zHfVqUIzhK35UwCkkMLg yUgssEpWGQTV75g2W8CmkD6xBkEyo4Q= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1730500718; a=rsa-sha256; cv=none; b=6e4OnU/heQGyfW6A+D9aWEspnrOJuGkhQQYoLy4sa9ZLtfQq7VeVcuOORB+bkNdm1rfL+P nM354OZA1zZLNT1S4jAddAAncAsRvJ+VKXIDJnyu0Hv+dHsYKvFQenUpjl8kThE2zRu+nc KI3lUdBGtCJsjVSAp8RkV1yonO1X5Rw= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=LEhrLwqB; spf=pass (imf22.hostedemail.com: domain of broonie@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=broonie@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 093865C491C; Fri, 1 Nov 2024 22:38:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 072F5C4CECD; Fri, 1 Nov 2024 22:39:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730500762; bh=JkmskpWLroWyTPtf1p/0xaay+Zwr1MUY5lzV+zGUd1c=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LEhrLwqByhfLvAU785JeArYUuInGTqkBsGV3r3plSQ8zSbQAV6fT+ET7wqEU5o5VA ct7o/GLXp2+/PbBbP1QN334NceDAeGev8dTIyBaNpZxzb6p0AY8Znr3vdNOeI/f1LS Oz+QIM7HGR+hvpLC20DDRetymBXJYfjj9VRTn08bKEm2t1Lp6PcPDnGni1/dN9RbXN p7KckOVoTXBme68zzAN3mCqqDK4u2art9j+inl0K6gITEYx7xgvFhacdYnCRnIbsBt biEVrtmlNKtzEwdNtS8V93i5t980S16YKJxmXvG9T5lwJBZeTTueW1wQdfH3d51/xM meKMFv06sf29g== Date: Fri, 1 Nov 2024 22:39:15 +0000 From: Mark Brown To: "Edgecombe, Rick P" Cc: "debug@rivosinc.com" , "Liam.Howlett@oracle.com" , "dave.hansen@linux.intel.com" , "bp@alien8.de" , "lorenzo.stoakes@oracle.com" , "hpa@zytor.com" , "mingo@redhat.com" , "tglx@linutronix.de" , "x86@kernel.org" , "vbabka@suse.cz" , "arnd@arndb.de" , "akpm@linux-foundation.org" , "linux-mm@kvack.org" , "linux-fsdevel@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arch@vger.kernel.org" Subject: Re: [PATCH RFC/RFT v2 2/2] kernel: converge common shadow stack flow agnostic to arch Message-ID: <7f392b4e-9970-42d4-8204-2aa967a5375d@sirena.org.uk> References: <20241016-shstk_converge-v2-0-c41536eb5c3b@rivosinc.com> <20241016-shstk_converge-v2-2-c41536eb5c3b@rivosinc.com> <7109dfcc6df5a610dcfe35a77bb7a84f8932485b.camel@intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="H7fCiCztkNSvBJxu" Content-Disposition: inline In-Reply-To: <7109dfcc6df5a610dcfe35a77bb7a84f8932485b.camel@intel.com> X-Cookie: We read to say that we have read. X-Stat-Signature: 341wpzu4yojgpxjdzzuiibt3dbgq9inw X-Rspam-User: X-Rspamd-Queue-Id: 4414DC000F X-Rspamd-Server: rspam02 X-HE-Tag: 1730500728-225881 X-HE-Meta: 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 3nZ+bPEy 9MYvCj5n9UN3k8+PRVBNjfQN5FPkSAPca4aLG6F+RQY7X+M0Q6EcfSjrZz98u5t38fBlgYsw4prz5Htz7FUsO6JTqTejmsFj2QipUQMd7ZpVrmmBAHpb1V79qUiX+IJAB19gh6dUDnvWqQfkaSqGVvMUqqH849dZezPe9xtVu+oX0l1S0W9n0q/eI5hLobJUOGg8X5srDyHSMx5WUzNsbXvNE/6yXXO/ZbamRpEAFIWh/ZGTXHZabjdur6/5GmteNVpG2JIIa4BZ0Ue7Kg4s56u+nOVRnWRRLnGLFVr/GdJXjjBa/h+zkoeMful6m4hEj0+brr0o4SLWnqCJPzaBNS7RNfmcZHN/Kr+En 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: --H7fCiCztkNSvBJxu Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Nov 01, 2024 at 09:50:27PM +0000, Edgecombe, Rick P wrote: > On Wed, 2024-10-16 at 14:57 -0700, Deepak Gupta wrote: > > - * The maximum distance INCSSP can move the SSP is 2040 bytes, before > > - * it would read the memory. Therefore a single page gap will be enough > > - * to prevent any operation from shifting the SSP to an adjacent stack, > > - * since it would have to land in the gap at least once, causing a > > - * fault. > I want to take a deeper look at this series once I can apply and test it, but > can we maybe make this comment more generic and keep it? I think it is similar > reasoning for arm (?), is there anything situation like this for risc-v? Or > rather, why does risc-v have the guard gaps? Yes, for arm64 you can only move the pointer in single frames so a single page is enough. --H7fCiCztkNSvBJxu Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmclWJIACgkQJNaLcl1U h9BbbAf/YCyway5BCg6C3KzepN1gz5b37UP2Bq3e+NcpcYbuR6W4n/objROMTtBc nsknhZwTf6tIRzlmJyJPi4i0IEVsBXMgH7oe77yvZ2z2Cgw7ZUteK3gGiYV3Z/Si XYIheFf3VcavqebwBiuSkBicYRUmpDtw41KHXjjh51KKCAM7j/fYp+ZCxJsvZINl VruJKtOVl/tyQ+BzFtRlWP/HJ8V3Lyc3bpHM7AMvAihfuOPKFgj/XGi591VRumor jil6i2Q2KioyFq7NMIWn40QQn5ewJNrNyvK2JK3Jj/Uf8EcQIsNlhPVUFSGMt34c MYRZ/U8CCx/7KkbjeOjuelYwP+ayMQ== =h97G -----END PGP SIGNATURE----- --H7fCiCztkNSvBJxu--