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 651D4C001DF for ; Tue, 1 Aug 2023 16:43:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B3B92940026; Tue, 1 Aug 2023 12:43:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AEB8B940010; Tue, 1 Aug 2023 12:43:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9B319940026; Tue, 1 Aug 2023 12:43:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 8891F940010 for ; Tue, 1 Aug 2023 12:43:51 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 2FA2F1A056B for ; Tue, 1 Aug 2023 16:43:51 +0000 (UTC) X-FDA: 81076107462.28.09B1987 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf19.hostedemail.com (Postfix) with ESMTP id 8DEE51A27F8 for ; Tue, 1 Aug 2023 16:40:03 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=abqS+G0u; spf=pass (imf19.hostedemail.com: domain of will@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=will@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=1690908005; 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=NTBwd29Dbu+ECP276LsKiM8HBDKaR00BKAB6CRCf3bE=; b=kWBiho8kMw5CognX4CkVrXPAPixzY3LSnY9MfDzIMoFttyY/GxdThv1t1HoXV7pilWU33+ O9wjtBobPbSdCixQAUXREacJxvd+6KW9GmRbsW5HFmrp42hJGIQcrDFPEix0FHLJ5KEDZW JX9Ci8cenNdytx1rJ0+kAgreF6rUjd4= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1690908005; a=rsa-sha256; cv=none; b=jRrj3e0r7K7l8mVsxRjnvJGTYEjRLks1U1KoCc3AEbjLa8NaexQA81sXCKBtXMIKUyMGId 7QSQEpoI2GQKX0ka6omi/GiQcx3hl5x1aoPwU5kpGrsSjSfkZFBq1HWZBf3VOUsOGOC3zW NXwFZ3+AflwQVe9+Kx8iWNXuu7Lc7qc= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=abqS+G0u; spf=pass (imf19.hostedemail.com: domain of will@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=will@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 995E0615C2; Tue, 1 Aug 2023 14:13:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C215FC433C7; Tue, 1 Aug 2023 14:13:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690899209; bh=NTBwd29Dbu+ECP276LsKiM8HBDKaR00BKAB6CRCf3bE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=abqS+G0uERa7fIKrH4hSw9IDBy+zR3n2e2RncQqAqkzlG6NQHu8J5iIFlkwrB657I oJQ0+vDyHimf0Zzmz13ZMAyco3wCnDXoFSci37voDkjQr4SVseAsIyVJ06v3CG1ZKX wA4zk4L/vjGB4EVHMfxhGACjxWZzRWGs+AESTu3SAB7pEpFPTu5QyCSKsYrmv6ocyz STvBOLI5/v9lmw1IkmkGMiZootxRVm5BrSrS3Z8ppbrLm97hcIZG9bJiqDSG26raqx VegkDKaNPneU+4IvGTtTT2RITGdJC90YBsdQ0YM0USvoHqq9xrcZJCf7t4mwUrCzhT F9wsepVvvxiMA== Date: Tue, 1 Aug 2023 15:13:20 +0100 From: Will Deacon To: Mark Brown Cc: Catalin Marinas , 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 v3 00/36] arm64/gcs: Provide support for GCS in userspace Message-ID: <20230801141319.GC26253@willie-the-truck> References: <20230731-arm64-gcs-v3-0-cddf9f980d98@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230731-arm64-gcs-v3-0-cddf9f980d98@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Queue-Id: 8DEE51A27F8 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: yrgn4exrs69tygt1txdf1fruww9dqfbr X-HE-Tag: 1690908003-833993 X-HE-Meta: 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 hRjldi7S RMOvf1FYCx2Lagi+lvnujTlNYQUqci/mYnk2l4cBs/+wPbHnuYo2p72GShO4ioHmZNsOmkA3RcHTsgHDxjZc4QhGaSIMuA7P/+Z2euTLiMzmniF1c9u7byEZHmM41JaW/KM/xzL/ok6KG7Dbnd9j8pOZl0DqQXdowA0gJFxV3FByWZTVU0BGWR7bLXhV1FOJtO5ucRLfK0UzkrExYGilHr3vvS9rScpZGDbPpTB+vO9WqrlXUs1/XcR+3jTJ4XXpF+Iv7tlSn7EVgbpJIgDdh/VE2tbX87y3rPz2SsiHVbbEJzhAi+KrSLG+L9pxZ8u1LVzOnMC4lp/iPHZ+Z1aAcYxXBlyg1aUiHDqMgW+3OqeHmZ5c= 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: On Mon, Jul 31, 2023 at 02:43:09PM +0100, Mark Brown wrote: > The arm64 Guarded Control Stack (GCS) feature provides support for > hardware protected stacks of return addresses, intended to provide > hardening against return oriented programming (ROP) attacks and to make > it easier to gather call stacks for applications such as profiling. Why is this better than Clang's software shadow stack implementation? It would be nice to see some justification behind adding all this, rather than it being an architectural tick-box exercise. Will