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 A58F5CD37AA for ; Tue, 3 Sep 2024 18:20:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2342C8D01C5; Tue, 3 Sep 2024 14:20:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1E46E8D016E; Tue, 3 Sep 2024 14:20:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 05DEA8D01C5; Tue, 3 Sep 2024 14:20:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id D40B48D016E for ; Tue, 3 Sep 2024 14:20:18 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 3CEA5C0657 for ; Tue, 3 Sep 2024 18:20:18 +0000 (UTC) X-FDA: 82524241716.04.4E549DF Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf23.hostedemail.com (Postfix) with ESMTP id 7A4D714000A for ; Tue, 3 Sep 2024 18:20:16 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ciUdQG6T; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf23.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=1725387510; 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=3M41hDuZ2hOv4A0wqx1B4EpRjBwVCpmQ+MYvSeDr0Yw=; b=g7uuIJ9Vs3U3rD0VO+1L9p8IQuboj1FiaY3H1FjRGFsBE/kw2FEcIvZ1QsqOcduhEapr6i RwvPilOQX/plB5ISqh1FRqkoS6xGUK7G2HPchKh2tRSacAi1NQLSu+klPsZpLT4w/+fqsE Jj4G1HcQ2++yvlp26WmZ8N77erTRAd8= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1725387510; a=rsa-sha256; cv=none; b=tPDGhIgFBezlvbVglt4Z0YwgQwFumQINApHcbR8aQdCSKoGdezYR9q+bMIapziK50d4Aa3 LdKQZB5Zc9R9dFDDK8vK0mais/0s7wNqQ5tPDGc8BkR/UDYHyd3xTAaEepeU1l6kOyk9SC NZzSX1ZIcVTKD2PlsRdDKwqnpaklinI= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ciUdQG6T; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf23.hostedemail.com: domain of broonie@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=broonie@kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id BDADF5C59E4; Tue, 3 Sep 2024 18:20:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05262C4CEC5; Tue, 3 Sep 2024 18:20:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725387614; bh=3M41hDuZ2hOv4A0wqx1B4EpRjBwVCpmQ+MYvSeDr0Yw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ciUdQG6Ttgi9yvvZQGiq8UopO75eB7vVzLKBng7HwibzPFRnXBalgGP0DHJOhsgYw 3uk4X//pO6AWblx6uj2/rrtcfZi8xJ+KLRhTGUIMHNMXYzXGdpl88AE1LNLYhQLrSP DF8KUTdzVN5U6fM8gZroVggjf3verSxfxLuJNEjmcXfbWXBE0OFnt2KZ4iEV5Vhk9j JeNKEHjQ3QpE+rmpaiNn2XI0qgA0oJV7QO0sGId48qZnT0wsdO40PdufRSPzAvFgKn YqlXDkAF0Dp4f65YVZerwA+zsLHpTSAMy3EtYLEl14MtxYmN71YQsS6p8hzMMNF/7p L/5KsXBbyQ2oQ== Date: Tue, 3 Sep 2024 19:20:02 +0100 From: Mark Brown To: Lorenzo Stoakes Cc: Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Russell King , Guo Ren , Huacai Chen , WANG Xuerui , "James E.J. Bottomley" , Helge Deller , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Naveen N Rao , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , "David S. Miller" , Andreas Larsson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Chris Zankel , Max Filippov , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Catalin Marinas , Will Deacon , Deepak Gupta , linux-arm-kernel@lists.infradead.org, linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-csky@vger.kernel.org, loongarch@lists.linux.dev, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org, Rick Edgecombe Subject: Re: [PATCH 3/3] mm: Care about shadow stack guard gap when getting an unmapped area Message-ID: <3ff7a6dc-a21a-4a53-b3d5-cc8b0b5333fb@sirena.org.uk> References: <20240902-mm-generic-shadow-stack-guard-v1-0-9acda38b3dd3@kernel.org> <20240902-mm-generic-shadow-stack-guard-v1-3-9acda38b3dd3@kernel.org> <6d91ca85-def3-422c-8fb2-76337136257d@lucifer.local> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="o37zrp9IxB4WCgx3" Content-Disposition: inline In-Reply-To: <6d91ca85-def3-422c-8fb2-76337136257d@lucifer.local> X-Cookie: Words must be weighed, not counted. X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 7A4D714000A X-Stat-Signature: g75aahzuqwro1uew8cgx4ir5bzd8jc16 X-Rspam-User: X-HE-Tag: 1725387616-920655 X-HE-Meta: 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 9qNZWlwD D5cyM8x7zRxhBh8p1Sj+oqIdb8/ODsd7Nk0eZvK9jXcEPgDNMXiYIpCJu2ORJEcoRb17Uk/OT2UAXG7hhW+JNhEoGccF8i1GbK870KyqJ+Il6MB8CZMlZSeEnb5kSQsuf2FMQaECLeiT+c2/qcRVEm8yYJPlnEgCPjNrhn5nHT8Jcsu3z1cnbkYJJuvp9ZlTLTfbLmlvSof3fZ4c771mF4AL2NdZ1xldBU1D0f4midMZYJHmMAIjTb/UhcDmgNxdp0tEQLH+BWK2YYQOGNYjfGPMp44PQxrVU8Tq5 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: --o37zrp9IxB4WCgx3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Sep 03, 2024 at 06:49:46PM +0100, Lorenzo Stoakes wrote: > On Mon, Sep 02, 2024 at 08:08:15PM GMT, Mark Brown wrote: > > On x86 there is a custom arch_get_unmapped_area() which was updated by the > > above commit to cover this case by specifying a start_gap for allocations > > with VM_SHADOW_STACK. Both arm64 and RISC-V have equivalent features and > > use the generic implementation of arch_get_unmapped_area() so let's make > > the equivalent change there so they also don't get shadow stack pages > > placed without guard pages. > Don't you need to unwind that change in x86 now you're doing it in generic code? No, x86 had a preexisting custom implementation for some other reason (hence the "updated by the above commit" part above) - the shadow stack support would most likely have been added in the core in the first place were it not for that. --o37zrp9IxB4WCgx3 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmbXU1EACgkQJNaLcl1U h9D6cgf/XDZdPu9OMFQe6TQgFZfL0q5O9mqkm+BWBPaJVUsfz+b1eJX8MY/X94i7 isw0bRIKXl4Rdgglf/Mjack/jKZI2dA1nVQtiA0++/6tT814x3Y/iykb6tAbghmy uinhNXZQlV9/DYrMjNAbBcGeFlMlKmRBSrZEuoHwLuaOsQ3CfzCxB7zqsWtaxrBk Ct7Jtsia48hr6Df5deBgMHgDTE6xyu7fxb9fDqVippx4fBJzXvjimEBvAG8OWp/z 77YIEDqfJ+JuDQvg3E5YL5EW1xarV++hvLacqfnaffNQFwngWwUWM8TyY7p5C4VK LKP++oAShrv2wbyvnGgxkpomt/Eb5g== =xc/U -----END PGP SIGNATURE----- --o37zrp9IxB4WCgx3--