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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2FD6FC3DA6F for ; Thu, 24 Aug 2023 15:44:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=dXqbVV990vJ7UwNQ2jCXU24jeYVMJY23awKSNPepVGs=; b=Y3Lrw4WxiHLLGk 6LQY9KYBcTL0CyKjibrX+TlHNuhUkfyp+5dGCmyZCIWnRQ1MIwoAmja/KuuDfsBIBe/nh84aVQcLz g7PMwQp7ziEcAXZUdIhTPXhiDx38yDRwoRBMwiTd66MQXIDZE3LWt2V9z5RsoE6HEjVwy1WZxPf5G DpRJ/RwM3jzLwLzPpiWmVmYizRMaHO4tr4XQVpuEIR0u5vl5KEvi2H9CQQSaZ+sBYQR9Bh0oD7sm+ srjnVWU4Kx8rLr5c2lWDbNKKSO6OmA5SmIUCssxTGC/a0Qpk98rfTxbM2F+OVqRzF25YGKHu6UVUZ DijOjQcBKH5fVDcfQzBg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qZCUx-003OZc-0L; Thu, 24 Aug 2023 15:43:51 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qZCUk-003OUN-0Q; Thu, 24 Aug 2023 15:43:39 +0000 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 87C5867110; Thu, 24 Aug 2023 15:43:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D722EC433C8; Thu, 24 Aug 2023 15:43:23 +0000 (UTC) Date: Thu, 24 Aug 2023 16:43:19 +0100 From: Catalin Marinas To: Mark Brown Cc: Szabolcs Nagy , 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 , "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 v4 03/36] arm64/gcs: Document the ABI for Guarded Control Stacks Message-ID: References: <43ec219d-bf20-47b8-a5f8-32bc3b64d487@sirena.org.uk> <227e6552-353c-40a9-86c1-280587a40e3c@sirena.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230824_084338_211843_B2C12CA9 X-CRM114-Status: GOOD ( 19.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Aug 23, 2023 at 07:16:52PM +0100, Mark Brown wrote: > On Wed, Aug 23, 2023 at 06:40:40PM +0100, Szabolcs Nagy wrote: > > i don't know if we can allow disabled gcs thread creation with locked > > gcs state. (i can see arguments both ways, so further prctl flag may > > be needed which may be another divergence from x86) > > I think that if we do add a new flag that'd just be new functionality, > the divergence would be in allowing configuration via clone3() rather > than the flag. TBH I'm not sure I see a use case for locking but > providing a mechanism for getting out of the lock, that seems very > questionable. You are right, once the configuration is locked a plain clone() or clone3() without a GCS pointer should be rejected. Is there a use-case for the unlocked configuration to allow disabling the GCS implicitly via a clone syscall? If we go for extending clone3, I wonder whether we should also introduce a sigaltstack2/3 ;). I haven't checked what the current patches do and won't have time until early September (on holiday from the end of today). -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel