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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 91E43F8FA6D for ; Tue, 21 Apr 2026 12:56:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1bgNf4YivZGu1nsDMHDmBZ+9sSBMSyPnPvxOcvLGcT0=; b=ez+hiurYheGOSSFg3teLjSaBiH UzfUN49fj5aJ2/uROxtOmrMX41gSr1gq5D/M3iXmTvBDO5ikBu1gbOyXXXF1v/fh7VEZ0YdtLsAxh VMuM4gBC90T9FWfdhI8rxHENRtOGxDzQUV4pQXOKeYwQYeq6f63Z5cF0Qvf/aP1SgU0DQRL6G7sti omZWreDw0ZOUT6+avAd5fp4AIzy9+5NIdQh7RyZeaH8WaVSNmZ+H6o8VHmScBgr2Tz4/K6aFkDdF+ e0Ka/gJ5fqROTOsDa3q1qhONeyqXHBb71lLmPtruB462roCVhanPICVFthAYH0XpZpk2S1cJKgy2F W2ySPPNg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wFAek-00000008cOh-11MA; Tue, 21 Apr 2026 12:56:46 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wFAeh-00000008cOI-3DW4 for linux-arm-kernel@lists.infradead.org; Tue, 21 Apr 2026 12:56:45 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C58DF25DC; Tue, 21 Apr 2026 05:56:34 -0700 (PDT) Received: from e124191.cambridge.arm.com (e124191.cambridge.arm.com [10.1.197.45]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8EB3D3FE76; Tue, 21 Apr 2026 05:56:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1776776200; bh=/ayGc21r8/ncAlc24Og8fknfgsFrnj75Oxhv3tWBRng=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qspZV0YwriFI+2AhIad+vv9vG37bn5utLcXEfijscBpcTasOdl/ALrfW9HZ0IN2wx 0swzgdLAUwyAHSuLchMs62R18YUcwxfwOk7X4PDsYUsQQC6PT6FJ4e9aOg7SghSIJO 6Nmkl3miMLQFs2Gtn18hdrhcEnzgdnLXxwmrCqe0= Date: Tue, 21 Apr 2026 13:56:28 +0100 From: Joey Gouly To: Jens Axboe Cc: Mark Brown , Catalin Marinas , Linux ARM Subject: Re: kernel-hwcap.h change causing full kernel rebuilds Message-ID: <20260421125628.GA3849283@e124191.cambridge.arm.com> References: <52fb2e8f-3e1c-4cf5-a02a-0d68beedd18b@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52fb2e8f-3e1c-4cf5-a02a-0d68beedd18b@kernel.dk> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260421_055643_892960_200B67AF X-CRM114-Status: GOOD ( 13.61 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi! On Tue, Apr 21, 2026 at 06:52:55AM -0600, Jens Axboe wrote: > Hi, > > Maybe this has already been reported, but a quick search on lore did > not find anything. So here goes... After commit: Here you go! https://lore.kernel.org/linux-arm-kernel/20260413-arm64-hwcap-gen-fix-v1-1-26c56aed6908@kernel.org/ and on it's in rc1 now: https://lore.kernel.org/linux-arm-kernel/aeaDFH0-2zhOQTxy@arm.com/ Thanks, Joey > > commit abed23c3c44f565dc812563ac015be70dd61e97b > Author: Mark Brown > Date: Mon Mar 2 22:53:16 2026 +0000 > > arm64/hwcap: Generate the KERNEL_HWCAP_ definitions for the hwcaps > > arch/arm64/include/generated/asm/kernel-hwcap.h is generated for > _every build_, which means that you can literally run make back to back > without _any_ source changes and you are rewarded with a full kernel > rebuild. Not sure how this ever got past any kind of testing, because > it's very noticeable. > > For now I've reverted this change locally as any kind of testing now > kicks off a full build, when a single file rebuild is all that is > needed. > > -- > Jens Axboe > > >