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 17022C54734 for ; Tue, 27 Aug 2024 12:54:04 +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=4l4Hildk3Mm2NxJx5Tv02rAjpvnSgTpUxJBiySeOnR4=; b=hr+IrHnlaL0UsWENJLuqWSC6q9 VBZ2692NGUd1pmSAH0X/v2wEsprHmnIX4RO2spMF1ZVhViBigbVzW9+CQ8J+EAyBBfjI5lOM5KaJ2 hoAqn/OjhpTWI0Ov1J2mdXBKkPKid4NjTtnFUMHKIyDGJE+l7dOcD7CeyECR5Ruwf+gohIbjN7P1m N94DUWxDCpiFMf4oWhy2xNVz+P2KGFRvGFaoi64xPfqCTKDYNvNPrREhPdkKTIMGeCX2dDJy+7ilS NPFyl69JRQBGFoCqU/BpgqX3uH+O9hY56G4hFjFStK6mp2G9G8elxOhXZqtp2XnhSJ8PHeLNBLuzb SjZ+g6iw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sivhr-0000000BLJq-2u3W; Tue, 27 Aug 2024 12:53:55 +0000 Received: from nyc.source.kernel.org ([2604:1380:45d1:ec00::3]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1siveo-0000000BKJN-3mvW for linux-arm-kernel@lists.infradead.org; Tue, 27 Aug 2024 12:50:48 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id E9D97A4198A; Tue, 27 Aug 2024 12:50:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F3E28C6106D; Tue, 27 Aug 2024 12:50:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1724763045; bh=qwDcptw+GorkjYb2aHEhqk3vhBLhz0T0r/3W8LEKW3A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KsU2C8e4LDwj/SADssPE/RQmKmgNsC5cSE+iGDc8XbTNn/TtPDiTQml00UjyBKiPQ 7StZK4bmdbuJ8mDViwf3tRSyU9D9OdOlf7npkI9dvh1AyFAQovBiia+V0Dqk9yamRs NZQILFjJIbw/+NdbJB+SbSfAnVuTUaLvzYcMz4e4sAaP8ybmhhPi7uO/I08TCEVzqK So84DwabR+DR6y6gysD+VnEddq70DmCemjIRcjgNuxdzny3RTwRVbqo/ELaJZtuRyu 9zzDOEfJWJCp3iDgzLdFqeuJua2wna0feA/4LX8/kmoUdx/BVipW7M7ezAq+k6n3CP QnSPSayqIaejg== Date: Tue, 27 Aug 2024 13:50:37 +0100 From: Will Deacon To: Alice Ryhl Cc: Catalin Marinas , Ard Biesheuvel , Jamie Cunliffe , Sami Tolvanen , Nathan Chancellor , Conor Dooley , Kees Cook , Masahiro Yamada , Nicolas Schier , Marc Zyngier , Mark Rutland , Mark Brown , Nick Desaulniers , Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Valentin Obst , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, rust-for-linux@vger.kernel.org Subject: Re: [PATCH v6] rust: support for shadow call stack sanitizer Message-ID: <20240827125037.GC4772@willie-the-truck> References: <20240826-shadow-call-stack-v6-1-495a7e3eb0ef@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240826-shadow-call-stack-v6-1-495a7e3eb0ef@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240827_055047_106081_48CAE614 X-CRM114-Status: GOOD ( 33.83 ) 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 Mon, Aug 26, 2024 at 02:22:52PM +0000, Alice Ryhl wrote: > This patch adds all of the flags that are needed to support the shadow > call stack (SCS) sanitizer with Rust, and updates Kconfig to allow only > configurations that work. > > The -Zfixed-x18 flag is required to use SCS on arm64, and requires rustc > version 1.80.0 or greater. This restriction is reflected in Kconfig. > > When CONFIG_DYNAMIC_SCS is enabled, the build will be configured to > include unwind tables in the build artifacts. Dynamic SCS uses the > unwind tables at boot to find all places that need to be patched. The > -Cforce-unwind-tables=y flag ensures that unwind tables are available > for Rust code. > > In non-dynamic mode, the -Zsanitizer=shadow-call-stack flag is what > enables the SCS sanitizer. Using this flag requires rustc version 1.82.0 > or greater on the targets used by Rust in the kernel. This restriction > is reflected in Kconfig. > > It is possible to avoid the requirement of rustc 1.80.0 by using > -Ctarget-feature=+reserve-x18 instead of -Zfixed-x18. However, this flag > emits a warning during the build, so this patch does not add support for > using it and instead requires 1.80.0 or greater. > > The dependency is placed on `select HAVE_RUST` to avoid a situation > where enabling Rust silently turns off the sanitizer. Instead, turning > on the sanitizer results in Rust being disabled. We generally do not > want changes to CONFIG_RUST to result in any mitigations being changed > or turned off. > > At the time of writing, rustc 1.82.0 only exists via the nightly release > channel. There is a chance that the -Zsanitizer=shadow-call-stack flag > will end up needing 1.83.0 instead, but I think it is small. > > Signed-off-by: Alice Ryhl > --- > Link: https://lore.kernel.org/rust-for-linux/20240808221138.873750-1-ojeda@kernel.org/ [1] > --- > Changes in v6: > - Move Kconfig requirements into arch/*/Kconfig. > - List non-dynamic SCS as supported on 1.82. This reflects newly added > things in rustc. > - Link to v5: https://lore.kernel.org/r/20240806-shadow-call-stack-v5-1-26dccb829154@google.com > > Changes in v5: > - Rebase series on v6.11-rc2. > - The first patch is no longer included as it was merged in v6.11-rc2. > - The commit message is rewritten from scratch. > - Link to v4: https://lore.kernel.org/r/20240729-shadow-call-stack-v4-0-2a664b082ea4@google.com > > Changes in v4: > - Move `depends on` to CONFIG_RUST. > - Rewrite commit messages to include more context. > - Link to v3: https://lore.kernel.org/r/20240704-shadow-call-stack-v3-0-d11c7a6ebe30@google.com > > Changes in v3: > - Use -Zfixed-x18. > - Add logic to reject unsupported rustc versions. > - Also include a fix to be backported. > - Link to v2: https://lore.kernel.org/rust-for-linux/20240305-shadow-call-stack-v2-1-c7b4a3f4d616@google.com/ > > Changes in v2: > - Add -Cforce-unwind-tables flag. > - Link to v1: https://lore.kernel.org/rust-for-linux/20240304-shadow-call-stack-v1-1-f055eaf40a2c@google.com/ > --- > Makefile | 1 + > arch/arm64/Kconfig | 7 ++++++- > arch/arm64/Makefile | 3 +++ > arch/riscv/Kconfig | 7 ++++++- > init/Kconfig | 1 - > 5 files changed, 16 insertions(+), 3 deletions(-) For the arm64 parts: Acked-by: Will Deacon In which tree do you plan to merge this? Cheers, Will