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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8DDF9C41513 for ; Fri, 28 Jul 2023 17:31:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230302AbjG1Rbn (ORCPT ); Fri, 28 Jul 2023 13:31:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233412AbjG1Rbi (ORCPT ); Fri, 28 Jul 2023 13:31:38 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52F2F3A99; Fri, 28 Jul 2023 10:31:11 -0700 (PDT) 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 E5335621B1; Fri, 28 Jul 2023 17:31:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F788C433C8; Fri, 28 Jul 2023 17:31:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690565466; bh=NXz5tKNsoYH5b9t6PkGaSvdNnq8EVbDx7LLDtyBWDIY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kEKS+ghKaHqzJ/CeAVUmffgp1syROs6M7poM0tlpzGzihFWzpmfvi2K85PgFarbuo RkBcIe75tLMn7XoYUUPhEjXBxGbvzFW6xn32Qzg/SEPgRlqNJ7ZV00NbZfU5yRRyZa jn3bpdlEYETGcDum4z742lJd6KwcgDw+lIfr6otYHl7RO8ePAuI1taZ3cPwmxE/PwJ wKJJvTonQcslSnqjiqKIy+MtAH0nqvGjUK5Hyzlni78cWnO89ixENQFj5Bae9AcGEH K6Fi4h9QSZCy9nrcmCfp6Y1ClZF8Pg2Q4KYKwIAlrtDzm85paoRya48V4qF09hybvv 7Sg5khTe78XFA== Date: Fri, 28 Jul 2023 10:31:03 -0700 From: Nathan Chancellor To: Arnd Bergmann Cc: Tiezhu Yang , linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, loongarch@lists.linux.dev, Linux-Arch , bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, loongson-kernel@lists.loongnix.cn Subject: Re: [PATCH v3 1/2] asm-generic: Unify uapi bitsperlong.h for arm64, riscv and loongarch Message-ID: <20230728173103.GA1299743@dev-arch.thelio-3990X> References: <1687443219-11946-1-git-send-email-yangtiezhu@loongson.cn> <1687443219-11946-2-git-send-email-yangtiezhu@loongson.cn> <20230727213648.GA354736@dev-arch.thelio-3990X> <1777400a-4d9c-4bdb-9d3b-f8808ef054cc@app.fastmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1777400a-4d9c-4bdb-9d3b-f8808ef054cc@app.fastmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org On Fri, Jul 28, 2023 at 01:00:30PM +0200, Arnd Bergmann wrote: > On Thu, Jul 27, 2023, at 23:36, Nathan Chancellor wrote: > > Hi Tiezhu and Arnd, > > > > On Thu, Jun 22, 2023 at 10:13:38PM +0800, Tiezhu Yang wrote: > >> Now we specify the minimal version of GCC as 5.1 and Clang/LLVM as 11.0.0 > >> in Documentation/process/changes.rst, __CHAR_BIT__ and __SIZEOF_LONG__ are > >> usable, it is probably fine to unify the definition of __BITS_PER_LONG as > >> (__CHAR_BIT__ * __SIZEOF_LONG__) in asm-generic uapi bitsperlong.h. > >> > >> In order to keep safe and avoid regression, only unify uapi bitsperlong.h > >> for some archs such as arm64, riscv and loongarch which are using newer > >> toolchains that have the definitions of __CHAR_BIT__ and __SIZEOF_LONG__. > >> > >> Suggested-by: Xi Ruoyao > >> Link: https://lore.kernel.org/all/d3e255e4746de44c9903c4433616d44ffcf18d1b.camel@xry111.site/ > >> Suggested-by: Arnd Bergmann > >> Link: https://lore.kernel.org/linux-arch/a3a4f48a-07d4-4ed9-bc53-5d383428bdd2@app.fastmail.com/ > >> Signed-off-by: Tiezhu Yang > >> --- > > > > > I think this change has backwards compatibility concerns, as it breaks > > building certain host tools on the stable releases (at least 6.4 and > > 6.1, as that is where I noticed this). I see the following error on my > > aarch64 system: > > > > $ make -skj"$(nproc)" ARCH=x86_64 CROSS_COMPILE=x86_64-linux- > > mrproper defconfig prepare > > In file included from /usr/include/asm/bitsperlong.h:1, > > from /usr/include/asm-generic/int-ll64.h:12, > > from /usr/include/asm-generic/types.h:7, > > from /usr/include/asm/types.h:1, > > from tools/include/linux/types.h:13, > > from tools/arch/x86/include/asm/orc_types.h:9, > > from scripts/sorttable.h:96, > > from scripts/sorttable.c:201: > > tools/include/asm-generic/bitsperlong.h:14:2: error: #error > > Inconsistent word size. Check asm/bitsperlong.h > > 14 | #error Inconsistent word size. Check asm/bitsperlong.h > > | ^~~~~ > > Thanks for the report. I'm still struggling to figure out what > exactly is going wrong here, and if this is a bug in the patch > I merged, or an existing bug that now causes a build failure instead > of some other problem. Totally understandable, I was really confused at first too. > > A reverse bisect of 6.4 to 6.5-rc1 points to this patch. This Fedora > > rawhide container has kernel-headers 6.5.0-0.rc2.git0.1.fc39 and the > > error disappears when I downgrade to 6.4.0-0.rc7.git0.1.fc39. I have not > > done a ton of triage/debugging so far, as I am currently hunting down > > other regressions, but I figured I would get an initial report out, > > since I noticed it when validating LLVM from the new release/17.x > > branch. If there is any additional information I can provide or patches > > I can test, I am more than happy to do so. > > One thing I think is going wrong here is that scripts/sorttable.c is > meant to run on the host (arm64) but includes the target (x86) > orc_Types.h header and the kernel-internal asm/bitsperlong.h instead Right. I will note sorttable is not the only utility that has this issue, I see the same problem coming from several files in tools/lib/subcmd when building several different architectures and arch/x86/entry/vdso/vdso2c.c at the very least. > of the uapi version. The sanity check in the kernel-side header > is intended to cross-check the CONFIG_64BIT value against the > __BITS_PER_LONG constant from the header. > > My first guess would be that this only worked by accident if the headers > defaulted to "#define __BITS_PER_LONG 32" in and #undef CONFIG_64BIT" > when include/generated/autoconf.h, but now the __BITS_PER_LONG value > is actually correct. That seems like a reasonable theory. I am still busy looking into other things today but I can try to double back to this on Monday if you don't make any progress. Cheers, Nathan