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 X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_GIT autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EDC00C48BE8 for ; Wed, 16 Jun 2021 08:06:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC69D6115C for ; Wed, 16 Jun 2021 08:06:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231882AbhFPIIa (ORCPT ); Wed, 16 Jun 2021 04:08:30 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:43266 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S231195AbhFPII3 (ORCPT ); Wed, 16 Jun 2021 04:08:29 -0400 X-UUID: 26ae6738386344e88258b709a2c20f1c-20210616 X-UUID: 26ae6738386344e88258b709a2c20f1c-20210616 Received: from mtkcas06.mediatek.inc [(172.21.101.30)] by mailgw02.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1960171326; Wed, 16 Jun 2021 16:02:54 +0800 Received: from MTKCAS06.mediatek.inc (172.21.101.30) by mtkmbs08n2.mediatek.inc (172.21.101.56) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 16 Jun 2021 16:02:52 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by MTKCAS06.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Wed, 16 Jun 2021 16:02:52 +0800 From: Lecopzer Chen To: CC: , , , , , , , , , Subject: Re: [PATCH] kbuild: lto: fix module versionings mismatch in incremental build Date: Wed, 16 Jun 2021 16:02:52 +0800 Message-ID: <20210616080252.32046-1-lecopzer.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <202106150821.B4D3E02@keescook> References: <202106150821.B4D3E02@keescook> MIME-Version: 1.0 Content-Type: text/plain X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Tue, Jun 15, 2021 at 02:26:58PM +0800, Lecopzer Chen wrote: > > > On Mon, Jun 14, 2021 at 01:51:09PM +0800, Lecopzer Chen wrote: > > > > When building modules(CONFIG_...=m), I found some of module versions > > > > are incorrect and set to 0. > > > > This can be found in build log for first clean build which shows > > > > > > > > WARNING: EXPORT symbol "XXXX" [drivers/XXX/XXX.ko] version generation failed, symbol will not be versioned. > > > > > > I'm doing this, and I don't see the problem: > > > > > > $ make LLVM=1 LLVM_IAS=1 distclean > > > $ make LLVM=1 LLVM_IAS=1 menuconfig > > > *enable LTO* > > > *enable a module* > > > $ make LLVM=1 LLVM_IAS=1 -j... > > > > > > What series of commands (and .config) shows this for you? > > > > Hi Kees, > > > > Thanks for you checking. > > > > After double checking in clean android kernel build, this causes by > > make version. > > (I have build failed in Linux LTO, > > seems it's not well support in contract to android?) > > > > I knew Google has LTO first in Android and upstream later, and most code > > are same as upstream, so the env here I use Android common kernel for > > easily testing. > > > > > > Test env is android common kernel: android12-5.4 [1] with its latest code > > and it builds from build.sh[2] > > > > $ BUILD_CONFIG=common/build.config.gki.aarch64 build/build.sh > > + make O=.... LLVM=1 LLVM_IAS=1 DEPMOD=depmod -j12 Image modules Image.lz4 > > > > With make set to v3.81, this can be reproduced with CONFIG_TEE=m. > > With version >= 4.2 this is not reproducible. > > Ah, very interesting. While there are tests in Makefile for > MAKE_VERSION, if we want to do this, it should likely be extended to > Kconfig, as that's where the initial version tests for things happen. We > could require MAKE_VERSION >= 4.2 for LTO? > > -Kees Yes, We can imitate how CLANG_VERSION was implemented in Kconfig. Accroding to GNU make release page[1], I've only tested for 3.81, 4.2 and 4.3. 4.2 was released in 2016, I think it's fine for LTO lowest version. [1] https://ftp.gnu.org/gnu/make/ thanks, Lecopzer