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 108D4C52D7C for ; Wed, 21 Aug 2024 12:55:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=BJdd+BfFZG/D09vD7q8fgzRHUq4ij9C/snJIOnLUiJQ=; b=IgH7QJ/hhpcfpea1dIcU7Gml7v hGp1rD0UECVFBnX6U4d+yvGchHHlSBFSDVcPYm9XMM84aOWuDj7PvRDlhaj1CCFGf6+seJBj7rYHu 02j60wzQSb9bUydhevTXjeSrg86M1aDaSPGFAFxWH0MkkBlu1seCpqhKaJs6ie4x5ZpRpt0zRAj3G H7dQQcbGzXqlJxGbdktaQrpRcMbPqneJnRCNrN5WI58vwe5THSgpNp3mwqEy26lVctD+BfSo9Vzd/ LXUF+CZHEPk40nG3hbxxKYKIVjYRRyr5IEZu7EY/CNmJaRXan763ehZXHPegqawfCEafxExMDZjZV fgZTTGUA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sgks3-0000000904S-2L7K; Wed, 21 Aug 2024 12:55:27 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sgkrK-00000008zus-2adG; Wed, 21 Aug 2024 12:54:44 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id DD48F60F82; Wed, 21 Aug 2024 12:54:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16F86C32782; Wed, 21 Aug 2024 12:54:35 +0000 (UTC) Date: Wed, 21 Aug 2024 13:54:33 +0100 From: Catalin Marinas To: Mark Brown Cc: Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy , Kees Cook , "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Florian Weimer , Christian Brauner , Thiago Jung Bauermann , Ross Burton , 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 v10 21/40] arm64/gcs: Implement shadow stack prctl() interface Message-ID: References: <20240801-arm64-gcs-v10-0-699e2bd2190b@kernel.org> <20240801-arm64-gcs-v10-21-699e2bd2190b@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240801-arm64-gcs-v10-21-699e2bd2190b@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240821_055442_719374_053BC9E7 X-CRM114-Status: GOOD ( 15.84 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Aug 01, 2024 at 01:06:48PM +0100, Mark Brown wrote: > Implement the architecture neutral prtctl() interface for setting the s/prtctl/prctl/ > +int arch_set_shadow_stack_status(struct task_struct *task, unsigned long arg) > +{ > + unsigned long gcs, size; > + int ret; > + > + if (!system_supports_gcs()) > + return -EINVAL; > + > + if (is_compat_thread(task_thread_info(task))) > + return -EINVAL; > + > + /* Reject unknown flags */ > + if (arg & ~PR_SHADOW_STACK_SUPPORTED_STATUS_MASK) > + return -EINVAL; > + > + ret = gcs_check_locked(task, arg); > + if (ret != 0) > + return ret; > + > + /* If we are enabling GCS then make sure we have a stack */ > + if (arg & PR_SHADOW_STACK_ENABLE) { > + if (!task_gcs_el0_enabled(task)) { > + /* Do not allow GCS to be reenabled */ > + if (task->thread.gcs_base) > + return -EINVAL; > + > + if (task != current) > + return -EBUSY; > + > + size = gcs_size(0); > + gcs = alloc_gcs(0, size); > + if (!gcs) > + return -ENOMEM; > + > + task->thread.gcspr_el0 = gcs + size - sizeof(u64); > + task->thread.gcs_base = gcs; > + task->thread.gcs_size = size; > + if (task == current) > + write_sysreg_s(task->thread.gcspr_el0, > + SYS_GCSPR_EL0); > + > + } > + } Nitpick: use a single 'if' instead of nesting (unless subsequent patches add more to the first block). Otherwise it looks fine. Reviewed-by: Catalin Marinas