From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0B60F1BFE1A; Tue, 27 Aug 2024 12:50:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724763046; cv=none; b=I3TjJ8ZPjOwTV2QERj/nwPPlOoSHWOCFPXPK41xXItxToplLt+RiACPNup2wfB7Djrtor8ENCIwBSVbpFmeCRg1Y/a5Lb8XpZGhmjDhIlScNnmxNQT96iGjvHJuIxmDJ6lDH8FL/MorqPrpOTFDyz3dbYyVJ1x95HujAGOIIuNw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724763046; c=relaxed/simple; bh=qwDcptw+GorkjYb2aHEhqk3vhBLhz0T0r/3W8LEKW3A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=udUH7NePoxZNzw/2H8ZL+hvPxVyvVxrYYRxLsItW/DpgwMUngeQ99temZW15+c5GY8b3PDMA2l5+n4GhAoDpnlzEPwXogDc20wI5FOr7e6yPapbmvDLkNhjOy6NUHqBHFZXaykBzRCjShwkGZZtkF6XIfbTxZp2lJOqcR+lpe2k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KsU2C8e4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KsU2C8e4" 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> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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) 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