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 78A2F22F3BE; Fri, 25 Apr 2025 07:40:52 +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=1745566852; cv=none; b=AYfQxaLsn108icyKFDpRGyeXpRfN3EdDyaxMzTBrliEqjwrhPaVMfszErp6pPsGgnY5eSfOcCoNsf8cqxORO4xuplBFKLkK9esuBrD+PyZWy59DdlgCIJbHCFmL9n/L29DA279EdVKbdBXMSDK6q130Q/YrdFWm5TVg29+yUFyg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745566852; c=relaxed/simple; bh=WpQFSnpwNwbZzu1PsGGV0iNBNs0zXtDESG2030ZXknQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JM2H2d8qdO0VOLYF1Sryi4lC4odpE1BxJ2AhU6y86bKD9zA5qpSAjpWnmPFrOypVYOrrZKC34nyjZ54gCGMpklVYJH5IKUwM7d1zNtdfceBwQTmYKV2uJqmRS1gEKiPlUasPgBFH2f8+goNqVIq507skMTpx7lA78RRGOvq5wP4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oGkoddQZ; 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="oGkoddQZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16F95C4CEEA; Fri, 25 Apr 2025 07:40:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745566851; bh=WpQFSnpwNwbZzu1PsGGV0iNBNs0zXtDESG2030ZXknQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oGkoddQZ5ObRjUUJcPqdJRMwI3z3dPMaaU1X/QJiQ7RmWj70x9xFRAWdOMHSk5o8B WlhKmkcmuJisZlPpUQyuNjSur7xMn7tNOGfEHeMx477kg21moTiasUqLagomhrBfZm 559Ubi2d/YIJfP34WUpC5oeNZijtq783bUbi5rCc0Wspw+wbILL7j52RiakFag15ta qsaqRKo7Vo5xehl/CSyyFSWt0b7R/JnV2wb+mzKHCXCXvgawjRXos87/Xwi0JFx7CP d0Dmsu7o0F+H3uqLH87Pn+TgfeaI2FtLAtF+y/2wkcdKL1bNZ6DRdvjfh0hsulg7OA X3H3tgJmcA4dw== Date: Fri, 25 Apr 2025 09:40:46 +0200 From: Ingo Molnar To: Arnd Bergmann Cc: Linus Torvalds , kernel test robot , oe-lkp@lists.linux.dev, kernel test robot , linux-kernel@vger.kernel.org, John Stultz , Thomas Gleixner , Stephen Boyd , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Peter Zijlstra Subject: Re: [RFC PATCH 0/15] x86: Remove support for TSC-less and CX8-less CPUs Message-ID: References: <202504211553.3ba9400-lkp@intel.com> <59198081-15e2-4b02-934f-c34dd1a0ac93@app.fastmail.com> 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: * Arnd Bergmann wrote: > > x86/platform: Remove CONFIG_X86_RDC321X support > > arch/x86, gpio: Remove GPIO_RDC321X support > > arch/x86, watchdog: Remove the RDC321X_WDT watchdog driver > > arch/x86, mfd: Remove MFD_RDC321X support > > x86/reboot: Remove the RDC321X reboot quirk > > I'm not sure about the RDC321X bits. Obviously the original > 321x/861x/vortex86sx chips are obsolete and can be removed, > but the product line is still actively developed by RDC and > DM&P, and I suspect that some of the drivers are still used > on 586tsc-class (vortex86dx, vortex86mx) and 686-class > (vortex86dx3, vortex86ex) SoCs that do run modern kernels and > get updates. So CONFIG_X86_RDC321X actively selects M486: +++ b/arch/x86/Kconfig config X86_RDC321X bool "RDC R-321x SoC" depends on X86_32 depends on X86_EXTENDED_PLATFORM select M486 ^^^^^^^^^^^ select X86_REBOOTFIXUPS But indeed the other drivers are not dependent on M486, at least overtly: arch/x86, mfd: Remove MFD_RDC321X support arch/x86, watchdog: Remove the RDC321X_WDT watchdog driver arch/x86, gpio: Remove GPIO_RDC321X support Although the watchdog driver has this indirect dependency: drivers/watchdog/Kconfig: depends on X86_RDC321X || COMPILE_TEST But the 486 kernel would work on any 586/686 upgraded boards as well. Anyway, I've dropped the mfd/watchdog/gpio removal patches, no harm in keeping these drivers, and I've switched the watchdog driver over to X86_32: config RDC321X_WDT tristate "RDC R-321x SoC watchdog" depends on X86_32 || COMPILE_TEST There's also no harm in keeping the southbridge reboot quirk I suppose, so I've dropped this as well: x86/reboot: Remove the RDC321X reboot quirk > > x86/cpu: Remove CPU_SUP_UMC_32 support > > x86/cpu: Remove TSC-less CONFIG_M586 support > > I think Winchip6 (486-class, no tsc, no cx8) and Winchip3D > (486-class, with tsc but no cx8) need to go as well then. Okay, agreed, I've added this patch to the tree: bf82539ad9f6 x86/cpu: Remove CONFIG_MWINCHIP3D/MWINCHIPC6 arch/x86/Kconfig.cpu | 28 ++++------------------------ arch/x86/Makefile_32.cpu | 2 -- arch/x86/include/asm/vermagic.h | 4 ---- 3 files changed, 4 insertions(+), 30 deletions(-) > At this point, maybe we can consider removing CONFIG_X86_GENERIC and > just always build kernels that work across a wide set of CPUs: Only > CMOV and PAE still require a CPU with the hardware support, and > X86_L1_CACHE_SHIFT needs to be at least 6 (64 byte) for > compatibility, but everything else should just be a tuning option. Agreed. Thanks, Ingo