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 97C36C001B0 for ; Wed, 19 Jul 2023 13:25:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 91D5C28005B; Wed, 19 Jul 2023 09:25:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8CD0928004C; Wed, 19 Jul 2023 09:25:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 76E2428005B; Wed, 19 Jul 2023 09:25:51 -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 6550728004C for ; Wed, 19 Jul 2023 09:25:51 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 17F36A02FA for ; Wed, 19 Jul 2023 13:25:51 +0000 (UTC) X-FDA: 81028434102.13.8186688 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf24.hostedemail.com (Postfix) with ESMTP id 2CB7C180008 for ; Wed, 19 Jul 2023 13:25:48 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=Gb9Diglh; spf=pass (imf24.hostedemail.com: domain of broonie@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=broonie@kernel.org; dmarc=pass (policy=none) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1689773149; 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=Q+Ai/WigE3ZKGlPZYs90Rx1iWdpMjWdMDmcdaXMo/0g=; b=Nec80qVfglDFA6xxgKtcFbYe3TqrFPAZa//ZjTKY7gc7PcGva1s68iMGWO3DypAFtQHnOY 643/Ej0LC5vbsspi8e73ZGchuyleq0A9vKK+v39HLJuYTrdoASzv6DMJfcARVzg+g1Sx6J IajJPGHCHlZjJiwZD7wIgA5cOCdJVcs= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1689773149; a=rsa-sha256; cv=none; b=kUQDs1+6XO32gAdyg7ODDrj8OKJoRPDULR0T5oDoF1owUxdPojuHnNfBwNi6K0hTUAR/WK HzpLB9ctnsS9tT36W1AbA2TV/EOZDbaKEh6of+cloNA/ipwY7i56iEyAyY10jpwxxa/Sep 9dftchk2CrmpcCBfYoaBB229FbJuVSs= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=Gb9Diglh; spf=pass (imf24.hostedemail.com: domain of broonie@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=broonie@kernel.org; dmarc=pass (policy=none) header.from=kernel.org Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C762961638; Wed, 19 Jul 2023 13:25:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 60714C433BA; Wed, 19 Jul 2023 13:25:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1689773147; bh=EyVLtL0y3pMG2CuYY0w75B4btgW07dMcezlAZDsSdHQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Gb9Diglh/i64PDngyNdt/GKb2Nk1ffhlx2iCYRVwYwJFFaIWeqdykk3XHsdIjxi+U ySo7EE75m9kyEmpGqZr+PUnM1neiLXdgMRuMhDCLMjYIpKB5stI7SDZFdeCnV7pSuT 3rxlgGugHsMh6Yu2Y2ZMz7uzUyqXc5OaAdIZuONNkooR8IAwPmhrzZzWDT1N1DwHYx RlTVeZoCs4CL7meIUWNo6SyAJaBckf8cXgHWQ1TpJoo/sQRvPGvbROxf9n80ltzbXE 5eGxexNIybAnY53SN4bcht+Z5iuvu040wYt+t4TGE0tkG8rPpOs8sUKiihTlsC+cQY ajt3gtR/VCWvQ== Date: Wed, 19 Jul 2023 14:25:38 +0100 From: Mark Brown To: Mike Rapoport Cc: Catalin Marinas , Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Kees Cook , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy , "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , 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 04/35] arm64/gcs: Document the ABI for Guarded Control Stacks Message-ID: <01dd7853-953d-4715-8cf0-c2f500065b55@sirena.org.uk> References: <20230716-arm64-gcs-v1-0-bf567f93bba6@kernel.org> <20230716-arm64-gcs-v1-4-bf567f93bba6@kernel.org> <20230719114437.GJ1901145@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="I9qodeRa311/Bc25" Content-Disposition: inline In-Reply-To: <20230719114437.GJ1901145@kernel.org> X-Cookie: They just buzzed and buzzed...buzzed. X-Rspamd-Queue-Id: 2CB7C180008 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: y7e1cswk4hqzpui9nx84yefxy9qwrh4y X-HE-Tag: 1689773148-656670 X-HE-Meta: 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 dfoOqJIN 1YQGdBW6Dpm3d5K56M0LFyJcFJNpza3BQEtRgmr+TshzsHtKpF9IpeVimQ3r0RIHbFkrhAzIyWENqv7SweFKwqgjeUgxw/UXLpMXzLKQvg/6wg+363NuNZaBOigcdNQHuVlGAgnp79vh/IBimu5PZPCqmOCoHN16H7bT1NyDTuTsYvRjh0C94tzgEAIktnXAavMJICm4gKYDw0cRR84tKOOJ+ot9TRGUHqmDBkuCOEsHk3dsgAUGzohcnVYsctT6WFxyol18J4JsI/o1luGHJ0qHk9ze9hxJZyRpvBkhXHSA5cnX8WYTZl49IYUwo6AjnbT6yDhPtQnLoofmbF+liuKaFrBa/6O+eI7zfFXQXB5eNJfYmbM8QsO5Jau0KYKg2i7gqaQHIIIs+smt39rnYaSALxRg91zRQj+jglmHJkfopem8= 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: --I9qodeRa311/Bc25 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jul 19, 2023 at 02:44:37PM +0300, Mike Rapoport wrote: > On Sun, Jul 16, 2023 at 10:51:00PM +0100, Mark Brown wrote: > > +* When set PR_SHADOW_STACK_ENABLE flag allocates a Guarded Control Sta= ck for >=20 > 'for' here looks excessi= ve ^ > > + and enables GCS for the thread, enabling the functionality controlle= d by > > + GCSPRE0_EL1.{nTR, RVCHKEN, PCRSEL}. It does scan fine to me as a native speaker. > > +7. ptrace extensions > > +--------------------- > > + > > +* A new regset NT_ARM_GCS is defined for use with PTRACE_GETREGSET and > > + PTRACE_SETREGSET. > > + > > +* Due to the complexity surrounding allocation and deallocation of sta= kcs and > > + lack of practical application changes to the GCS configuration via p= trace > > + are not supported. > On x86 CRIU needed to be able to temporarily unlock shadow stack features > to recreate the shadow stack of the thread being restored. I presume CRIU > will need something like that on arm64 as well. It would be good to understand why and what exactly is needed here. I'm guessing the main thing would be stores? It's relatively easy to add features later, I think I'll just add support for everything except enable just now. --I9qodeRa311/Bc25 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmS35FEACgkQJNaLcl1U h9ATlQf9HMvGT285Dxb1K98/IQO88I6xjkJKw25NyYtFdnj3sDQr/5mkdc17dstk 89MZPCDWgwC0akok+8SB6yCnT8x6dYbpiCgo7RkJXlfEhqR+xhvrJ7N+VRcoW4Uz ZZuPeiCqQs9GwvjBL9y0oD00oCZeIh/tfYI0cti4uHuUDaIiOjy6E9x96TGWTxBu l85odWvjI7U0wOUXQQL9qoDQCBU3bO52EN0k30ch7ILF9YAwR/NgAISqgoHreQ7d LrmfFdQSTWQiqh9/zau9U7ZESH/kw3vLVBo/TZd+pzuMnc1g+rxyKEHVZoJi1DBh 3Tt8WxOzSOFTarknQTMyOSKwRH7q9w== =EN0T -----END PGP SIGNATURE----- --I9qodeRa311/Bc25--