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 69B211B0F19 for ; Wed, 9 Apr 2025 21:34:11 +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=1744234451; cv=none; b=AMAlBieuD5JhA+c6n2619mFTbhGDFo2aGfg4cfyF5p2V8cyfu6iKC2BNh/iCJQSV/AnaG/g+/DQw9VYrgQDbh6fKvTZd4o9IHQ1NlbosQrMrq80IhyKGFogNsZHjlIi9Rd+h42SxwlFtR2psY7O06PcSNknnmHWLqXPlH1yf2Q0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744234451; c=relaxed/simple; bh=a48WLQkkP4gWo/eLBpfCmDza6nZ39Kc1DDQYC5pcMAg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=J/gOpor2NnW8sQJYQLd6+0dCKks1Y4YdjDqijOYa6g1vNFKrtyZcnI5BV0yc4Ih2ZbzafVL3RTUfpDns26qcu22jpSI9KGuzdQJz3+X0v6J5ZRZLEiC4/Xr6w0flObM3oQrZigm4Eh8SzpDhzpE50WMoVLmF2wgT+qpAFDknb/A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nufb9xb9; 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="nufb9xb9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA986C4CEE2; Wed, 9 Apr 2025 21:34:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744234450; bh=a48WLQkkP4gWo/eLBpfCmDza6nZ39Kc1DDQYC5pcMAg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nufb9xb9hRrg4Y4JrZG03t9mCjGEsDxSMzfT4DyDqc41mI5iHEWFp12mICAsO9s8A d+4v0ZQgYN81AyalzmB/+s0s/czMQpYOnWWyzm3x2c4KPLhkwRvofjP7VZHW1P0fNq J2b1Ix2NGLnF2PD4zkPRyvqYIIqNE3jHH60J7z4b1uGnuYDLWTcYP8UpYwJDTMaC9F XqqBQq+zBwyDsygR0jioHQUbHD85XyBBZHerC5K+fRobaXlj7nw+94qbSclL54Ppd7 Z1z+fr9iwNFExIhczcFdOP7x4iebNYx49syYV/OVHuvMtlfmuAhJDv8kA8nYACy3HU Zx4GYNvheJtOA== Date: Wed, 9 Apr 2025 23:34:06 +0200 From: Ingo Molnar To: Shuah Khan Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, hpa@zytor.com Subject: Re: [PATCH] x86/Kconfig: Fix dependency for X86_DEBUG_FPU Message-ID: References: <20250407231057.328010-1-skhan@linuxfoundation.org> Precedence: bulk X-Mailing-List: linux-kernel@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: * Shuah Khan wrote: > On 4/8/25 00:54, Ingo Molnar wrote: > > > > * Shuah Khan wrote: > > > > > Compile fails when X86_DEBUG_FPU is enabled and X86_REQUIRED_FEATURE_FPU is > > > disabled. Add explicit dependency on X86_REQUIRED_FEATURE_FPU to fix it. > > > > > > ../arch/x86/kernel/fpu/regset.c:411:(.text+0x4cf2f): undefined reference to `fpregs_soft_get' > > > ld: vmlinux.o: in function `fpregs_set': > > > ../arch/x86/kernel/fpu/regset.c:445:(.text+0x4d0da): undefined reference to `fpregs_soft_set' > > > ld: vmlinux.o: in function `copy_fpstate_to_sigframe': > > > ../arch/x86/kernel/fpu/signal.c:197:(.text+0x4da98): undefined reference to `fpregs_soft_get' > > > > > > > So I cannot reproduce this build failure on either v6.14 or v6.15-rc1: > > > > starship:~/tip> git describe > > v6.15-rc1 > > > > starship:~/tip> grep -E 'X86_32=|M486SX=|X86_REQUIRED_FEATURE|X86_DEBUG_FPU' .config > > CONFIG_X86_32=y > > CONFIG_M486SX=y > > CONFIG_X86_REQUIRED_FEATURE_ALWAYS=y > > CONFIG_X86_DEBUG_FPU=y > > > > starship:~/tip> make -j128 ARCH=i386 bzImage modules > > > > ... > > Kernel: arch/x86/boot/bzImage is ready (#5) > > > > > Signed-off-by: Shuah Khan > > > --- > > > 6.14 compile worked without X86_REQUIRED_FEATURE_FPU enabled. Might be a > > > new dependency. Enabling X86_REQUIRED_FEATURE_FPU fixed it for me on my > > > test system. > > > > So vanilla v6.14 does not have X86_REQUIRED_FEATURE Kconfig flags, at > > all: > > > > starship:~/tip> grep FPU .config > > CONFIG_ARCH_HAS_KERNEL_FPU_SUPPORT=y > > CONFIG_X86_DEBUG_FPU=y > > # CONFIG_TEST_FPU is not set > > > > Because X86_REQUIRED_FEATURE_FPU is a new v6.15-rc1 feature, introduced > > via: > > > > 3d37d9396eb3 ("x86/cpufeatures: Add {REQUIRED,DISABLED} feature configs") > > > > I have no doubt you are seeing this build failure - but I think there > > might be some other .config detail required to reproduce it, not > > mentioned in your changelog. Could you please send the config you used? > > > > Config attached. > > grep _FPU /boot/config-6.14.0+ > CONFIG_ARCH_HAS_KERNEL_FPU_SUPPORT=y > CONFIG_X86_DEBUG_FPU=y > # CONFIG_TEST_FPU is not set > > I noticed you are building ARCH=i386 - can you reproduce this > with x86_64? That is what I am building. > > thanks, > -- Shuah > # > # Automatically generated file; DO NOT EDIT. > # Linux/x86 6.14.0 Kernel Configuration > # > CONFIG_CC_VERSION_TEXT="gcc (Debian 14.2.0-17) 14.2.0" Is this a vanilla v6.14 kernel? Because on upstream v6.14 'make oldconfig' gives me: Generate BTF type information (DEBUG_INFO_BTF) [N/y/?] (NEW) Maybe different build environment? ... and after answering that with 'N' the build succeeds: LD arch/x86/boot/setup.elf OBJCOPY arch/x86/boot/setup.bin BUILD arch/x86/boot/bzImage Kernel: arch/x86/boot/bzImage is ready (#3) More importantly, X86_REQUIRED_FEATURE_FPU *does not exist* in the vanilla v6.14 kernel, it's a new v6.15 feature. So this part of your changelog totally doesn't apply to a v6.14 kernel: > > > Compile fails when X86_DEBUG_FPU is enabled and X86_REQUIRED_FEATURE_FPU is > > > disabled. Add explicit dependency on X86_REQUIRED_FEATURE_FPU to fix it. Thanks, Ingo