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 177E2C00528 for ; Tue, 1 Aug 2023 17:03:48 +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=MUMtNrsnAMVKAugfrJ5pwxvRZLDQmZU9xCWnBwdue2Y=; b=2UmPpgl2dLCDdx g3rFwa5go+RIIyTqzrJoOHxAGZfGuJcLDw2s3at9iAcq5Hgv6aqlYYCgiYnPyZGXb0WZPMdxRPc7j mMm9favEdFwNYquJ3VSMh5e0FQkZo0WdzSpOx3D4ENMabvfMo8yKNxX+KCJfiUsyqCbvX2Qt2AHhl KrfvfWRuXQeLM6zK/wTijcn9xv7Y5yIHzfh90IB1jlz3gjcpNhYFNpBbMDjBS7Xnq9lHE8PY+MXxj 82EKeonYr1+POuV170sAx2pWtogg6Akgo0w9Ftx+4cDTj/Hbkxks77B2R/vUX2OxAMHnjFZWuCtfG fX+Vc96dhunRk4i2jRMQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qQsmK-002s5P-09; Tue, 01 Aug 2023 17:03:24 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qQsmH-002s4H-36; Tue, 01 Aug 2023 17:03:23 +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 7EDDC61633; Tue, 1 Aug 2023 17:03:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 14158C433C8; Tue, 1 Aug 2023 17:03:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690909400; bh=n2/9ktpmINrFVuBWg1KAR2bAcG2NpG4kfEtaUDByDfs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AA0UkNhQxwECDyCEaDtc6JhBhvuvyCYYCaSh4HblOm5/sFOqJy8oy4lzt1PHsqe/d TNp/HD+vd9HlKtv5qMTIS+koyMnH6IxwcAdwNwXp4F5+zwZgvrnFbpNoU+QmQ8b5J3 ddlGURjkJRGzvvXYAv/2/xdGEsvIazcCS7ipemT/wemv7xW5NPdaO+scLqNwkzr3kd QYfygusILQtsW8OYGbFyAk8m/i1xYFxg47ufEb41rqQx5La8ZysCvnd1hWLGpVELSo 6atnVwdyqVnvxRrlqLIxYCR2TAHb6qdezWZ2QfOYTjqX/DgeT6WtV9UpJOx4DAmJz+ ldxqcY8ezOQig== Date: Tue, 1 Aug 2023 20:02:31 +0300 From: Mike Rapoport To: Mark Brown 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 v3 11/36] arm64/mm: Map pages for guarded control stack Message-ID: <20230801170231.GC2607694@kernel.org> References: <20230731-arm64-gcs-v3-0-cddf9f980d98@kernel.org> <20230731-arm64-gcs-v3-11-cddf9f980d98@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230731-arm64-gcs-v3-11-cddf9f980d98@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230801_100322_083966_4BA88C59 X-CRM114-Status: GOOD ( 23.30 ) 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 Mon, Jul 31, 2023 at 02:43:20PM +0100, Mark Brown wrote: > Map pages flagged as being part of a GCS as such rather than using the > full set of generic VM flags. > > This is done using a conditional rather than extending the size of > protection_map since that would make for a very sparse array. > > Signed-off-by: Mark Brown > --- > arch/arm64/mm/mmap.c | 17 ++++++++++++++++- > 1 file changed, 16 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c > index 8f5b7ce857ed..e2ca770920ed 100644 > --- a/arch/arm64/mm/mmap.c > +++ b/arch/arm64/mm/mmap.c > @@ -79,8 +79,23 @@ arch_initcall(adjust_protection_map); > > pgprot_t vm_get_page_prot(unsigned long vm_flags) > { > - pteval_t prot = pgprot_val(protection_map[vm_flags & > + pteval_t prot; > + > + /* > + * If this is a GCS then only interpret VM_WRITE. > + * > + * TODO: Just make protection_map[] bigger? Nothing seems > + * ideal here. > + */ I think extending protection_map and updating adjust_protection_map() is cleaner and probably faster. > + if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) { > + if (vm_flags & VM_WRITE) > + prot = _PAGE_GCS; > + else > + prot = _PAGE_GCS_RO; > + } else { > + prot = pgprot_val(protection_map[vm_flags & > (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]); > + } > > if (vm_flags & VM_ARM64_BTI) > prot |= PTE_GP; > > -- > 2.30.2 > > -- Sincerely yours, Mike. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel