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 0C9C6C7EE29 for ; Tue, 13 Jun 2023 11:56:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4CAB76B0075; Tue, 13 Jun 2023 07:56:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 47AC56B0078; Tue, 13 Jun 2023 07:56:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 36A976B007B; Tue, 13 Jun 2023 07:56:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 2A03C6B0075 for ; Tue, 13 Jun 2023 07:56:06 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 07E5740492 for ; Tue, 13 Jun 2023 11:56:05 +0000 (UTC) X-FDA: 80897571090.14.2112080 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf29.hostedemail.com (Postfix) with ESMTP id 3EA60120015 for ; Tue, 13 Jun 2023 11:56:01 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=cJlSzc9c; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf29.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=1686657362; 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=Y55L/ifTD+Az3stG2Sj9E0dJ66FX1dAYyv7iV54FE38=; b=VkLEqD+8qQgdS/QkMTFhgNcaG6oCSGRdp2/buYga9V0O6/YWUwfcV5LPkqPk15OyEPcMbW 2C1g8ZNDC22FmzbG++hekbCfT55mIsIXZOqsop+lfhxyeDS75lHBwfZCfRXnOmT8WEFRGP x8jb6SVaCwibWkjqHQVhR4hqvtnDomk= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=cJlSzc9c; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf29.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=1686657362; a=rsa-sha256; cv=none; b=VJl4/8DcrTNwyii+Ha1zuzwdVmkJEZvuBw92P8LD9uS0Q+npcGQlOR0PiffPIHQhPm4HvR 7yDq1DIkH4Yp01zRqCdQt3PbMaScAWCzFPHiAOdaT3XTuYvLdl//EJE+oTKSEkVEAMRnnO 9FkBM+IwIzQsXfY8y2aExIpn6NJCIdg= Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0F60363548; Tue, 13 Jun 2023 11:56:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EACCDC433D2; Tue, 13 Jun 2023 11:55:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686657360; bh=Y55L/ifTD+Az3stG2Sj9E0dJ66FX1dAYyv7iV54FE38=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cJlSzc9cAgm+2yPlvuu8gZ/T9bYn86hE9l2Db7NKeGcKpGhGvt7nMuKa9vtZJwAT7 0Pmee1IYLv6zI2hlTDbTl6kEbzuR1MPKb0GXqZkfxDGQN3LMMHlPbOmipHaUitPNM4 jBKIhm7wEHcU4eP3gK1FD9EmtjFk8kbAc+SOmOedWRYnvFr4EU/ZjtWIc91Cnva7MV hqMk3ik2IP8ek/EQJOmpQZqBnsvWOCw6XrnSMmjExBuNtmzzbjCyLNhYBa1kXiNB4P nkM/bQf3AFb+1byGT0Q1A0J92v6m3KwLTngcBazzoy7js0bJb/+ns83TVxjGjk/Ojs japRf5kSxwZmg== Date: Tue, 13 Jun 2023 12:55:48 +0100 From: Mark Brown To: Rick Edgecombe Cc: x86@kernel.org, "H . Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H . J . Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , Weijiang Yang , "Kirill A . Shutemov" , John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, akpm@linux-foundation.org, Andrew.Cooper3@citrix.com, christina.schimpe@intel.com, david@redhat.com, debug@rivosinc.com, szabolcs.nagy@arm.com, torvalds@linux-foundation.org, Yu-cheng Yu , Pengfei Xu Subject: Re: [PATCH v9 23/42] Documentation/x86: Add CET shadow stack description Message-ID: <0b7cae2a-ae5b-40d8-9ae7-10aea5a57fd6@sirena.org.uk> References: <20230613001108.3040476-1-rick.p.edgecombe@intel.com> <20230613001108.3040476-24-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="kfP6EvgSuUvXOsjA" Content-Disposition: inline In-Reply-To: <20230613001108.3040476-24-rick.p.edgecombe@intel.com> X-Cookie: Not a flying toy. X-Rspamd-Queue-Id: 3EA60120015 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: iu7n98y9677ekue3hdibduu6f6j8esny X-HE-Tag: 1686657361-523924 X-HE-Meta: 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 7uWuudZf UAS2outifjT3Y45/UHGA+cOe1LCn97aA4yGQYvsh2xX/Ig4fmCPW1s5CrYozBPD8Za7pkX5Bi5r/VRIPLIoKxfNN7zOSpaJXnVh/uThE3liT4h2uMvw1Gty2UrCoBPP/gzUig1Fl3waDsPMEuHryJzRORLOo5Blnso/mgpEXOgm+d5e7tDeiieDrHW4tcPPeHGuDGM03R9LnvOy0ILoeP+H9qP9az0QrXlzx9ImM0okkfoEqCSgg3oIN5t6UIZOVipPVreHzFZ/AJxoxqnKywBixkw7WUqjmwZKMzwLmEePRuxLFRaP02C4/kHzyR+xT2DaWTFV+sCnaJnDTvM5RvZDvtP0HehstGOrCALdU4qT7vhT4seyh+mxwNEls/epRM1PbC/+EXABxxtXNmdFTXinNbTuchSHCHQE8h 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: --kfP6EvgSuUvXOsjA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Jun 12, 2023 at 05:10:49PM -0700, Rick Edgecombe wrote: > +Enabling arch_prctl()'s > +======================= > + > +Elf features should be enabled by the loader using the below arch_prctl's. They > +are only supported in 64 bit user applications. These operate on the features > +on a per-thread basis. The enablement status is inherited on clone, so if the > +feature is enabled on the first thread, it will propagate to all the thread's > +in an app. I appreciate it's very late in the development of this series but given that there are very similar features on both arm64 and riscv would it make sense to make these just regular prctl()s, arch_prctl() isn't used on other architectures and it'd reduce the amount of arch specific work that userspace needs to do if the interface is shared. It should also be possible to support both interfaces for x86 I guess, though that feels like askng for trouble. --kfP6EvgSuUvXOsjA Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmSIWUMACgkQJNaLcl1U h9Decwf/Sfj1gjBXiige5kMFXXsGESCn0ysC4UryS29Y6kt4AZaDRY4e+Sav+q1E HJvMz1T1PvtW/of626ohvIdHHQfnw/cgBY8fiJty2koBqH3rLv49GkdgFBqGQadw i6mt0r8Iic3mgMA0U0vKYbaVRH3XFW57t/wHv/s0ZXymAp/gfHVEu19h/mJ5Q6Id VcxOUUbwLG8iAQqf4LeFqinIuDMF/RLh8ww2N7qfmZAjtZjVR1sK9EZEL3wi7rPf TXkYE2ytzOBsdr20PSk0IPDn6THMit+hJN13KtV+fC1CR4pUrPpV34smNhxLdKz4 w23fBr1HzZUByK5stGOoiP+mPWjeqQ== =Bwcu -----END PGP SIGNATURE----- --kfP6EvgSuUvXOsjA--