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 9B34F4681 for ; Thu, 6 Oct 2022 17:36:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C33AC433C1; Thu, 6 Oct 2022 17:36:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1665077771; bh=p7WWSAL6ZEAp08YxCy84XfVzYJ+eRQtdUq8MkjpUoHk=; h=From:To:Cc:Subject:Date:From; b=b9c5Uydrjv8pk3uGlZE3vwB+UQf/6haH4DdHHdZca9dUT+SlykCR9/SgHAz6IeIKR Jqsk1o65vApJ1L7m/tMWyMaTQ6ndEUWTsyVlSnx4r5nGK9q3NU/FtV4V2BniQZVCja AHyZP562lYHjcSGlL4QsLvDnCUS/ooxqeZsT9IVjGLvplhn3fyQjhdGCB7W1b4tXxj bbci+Ym9N7TtS52f4Yyl36wJ3Q2wEku6l4RLumK9YHBFMnbChNGGIliZ+AqpdCxfuL jmppVEh2hNQCZIqIePcNESF8DMwUs9YMtCw946iWeYq1GnYIJX6DHdA4u3Vkwa/VNs xrIwV9v4kyT1A== From: Conor Dooley To: Palmer Dabbelt , Nathan Chancellor , Nick Desaulniers Cc: Tom Rix , Conor Dooley , Dao Lu , Heiko Stuebner , Guo Ren , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev Subject: [PATCH 0/2] (attempt to) Fix RISC-V toolchain extension support detection Date: Thu, 6 Oct 2022 18:35:19 +0100 Message-Id: <20221006173520.1785507-1-conor@kernel.org> X-Mailer: git-send-email 2.37.3 Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Conor Dooley Hey, This came up due to a report from Kevin @ kernel-ci, who had been running a mixed configuration of GNU binutils and clang. Their compiler was relatively recent & supports Zicbom but binutils @ 2.35.2 did not. Our current checks for extension support only cover the compiler, but it appears to me that we need to check both the compiler & linker support in case of "pot-luck" configurations that mix different versions of LD,AS,CC etc. Linker support does not seem possible to actually check, since the ISA string is emitted into the object files - so I put in version checks for that. The checks have gotten a bit ugly since 32 & 64 bit support need to be checked independently but ahh well. As I was going, I fell into the trap of there being duplicated checks for CC support in both the Makefile and Kconfig, so as part of renaming the Kconfig symbol to TOOLCHAIN_HAS_FOO, I dropped the extra checks in the Makefile. This has the added advantage of the TOOLCHAIN_HAS_FOO symbol for Zihintpause appearing in .config. I pushed out a version of this that specificly checked for assember support for LKP to test & it looked /okay/ - but I did some more testing today and realised that this is redudant & have since dropped the as check. I tested locally with a fair few different combinations, to try and cover each of AS, LD, CC missing support for the extension. The one that I am left wondering about is Zicsr/Zifencei. Our Makefile has: > # Newer binutils versions default to ISA spec version 20191213 which moves some > # instructions from the I extension to the Zicsr and Zifencei extensions. > toolchain-need-zicsr-zifencei := $(call cc-option-yn, -march=$(riscv-march-y)_zicsr_zifencei) > riscv-march-$(toolchain-need-zicsr-zifencei) := $(riscv-march-y)_zicsr_zifencei I'd like to also move that one to Kconfig rather than the Makefile so that, again, it shows up in .config etc. But as Zicsr/Zifencei do not appear to be emitted into the object files it's not a fix and can be a follow-on patch if my approach here is not entirely off-the-wall. I am not 100% on the LD/LLD versions that I picked, I went off of a `git branch -a --contains` of the first commits I found that with mention of the extension. Please scream if I got it wrong, I'm not overly familar with where to find this sort of info for the toolchains. Thanks, Conor. Conor Dooley (2): riscv: fix detection of toolchain Zicbom support riscv: fix detection of toolchain Zihintpause support arch/riscv/Kconfig | 17 +++++++++++++---- arch/riscv/Makefile | 6 ++---- arch/riscv/include/asm/vdso/processor.h | 2 +- 3 files changed, 16 insertions(+), 9 deletions(-) -- 2.37.3