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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 5C5C2C4646D for ; Wed, 8 Aug 2018 13:16:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2225721A09 for ; Wed, 8 Aug 2018 13:16:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2225721A09 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727258AbeHHPgA (ORCPT ); Wed, 8 Aug 2018 11:36:00 -0400 Received: from ozlabs.org ([203.11.71.1]:51221 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727078AbeHHPgA (ORCPT ); Wed, 8 Aug 2018 11:36:00 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id 41lsN34l38z9s0n; Wed, 8 Aug 2018 23:16:19 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au From: Michael Ellerman To: Andrew Morton , Geert Uytterhoeven Cc: Linux Kernel Mailing List , Dan Williams , linuxppc-dev , "npiggin\@gmail.com" Subject: Re: Build regressions/improvements in v4.17-rc1 In-Reply-To: <87lg9hb12y.fsf@concordia.ellerman.id.au> References: <1523884165-17044-1-git-send-email-geert@linux-m68k.org> <20180806155440.9dcb271a3b075bd964aec60f@linux-foundation.org> <87lg9hb12y.fsf@concordia.ellerman.id.au> Date: Wed, 08 Aug 2018 23:16:16 +1000 Message-ID: <87d0utati7.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Michael Ellerman writes: > Andrew Morton writes: >> On Mon, 6 Aug 2018 12:39:21 +0200 Geert Uytterhoeven wrote: >> >>> CC Dan, Michael, AKPM, powerpc >>> >>> On Mon, Apr 16, 2018 at 3:10 PM Geert Uytterhoeven wrote: >>> > Below is the list of build error/warning regressions/improvements in >>> > v4.17-rc1[1] compared to v4.16[2]. >>> >>> I'd like to point your attention to: >>> >>> > + warning: vmlinux.o(.text+0x376518): Section mismatch in reference from the function .devm_memremap_pages() to the function .meminit.text:.arch_add_memory(): => N/A >>> > + warning: vmlinux.o(.text+0x376d64): Section mismatch in reference from the function .devm_memremap_pages_release() to the function .meminit.text:.arch_remove_memory(): => N/A >> >> hm. Dan isn't around at present so we're on our own with this one. >> >> x86 doesn't put arch_add_memory and arch_remove_memory into __meminit. >> x86 does >> >> #ifdef CONFIG_MEMORY_HOTPLUG >> int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap, >> bool want_memblock) >> { >> ... >> >> >> So I guess powerpc should do that as well? > > But we only recently added it to fix a section mismatch warning: > > WARNING: vmlinux.o(.text+0x6da88): Section mismatch in reference from the function .arch_add_memory() to the function .meminit.text:.create_section_mapping() > The function .arch_add_memory() references > the function __meminit .create_section_mapping(). > This is often because .arch_add_memory lacks a __meminit > annotation or the annotation of .create_section_mapping is wrong. > > > I think the problem is that the section mismatch logic isn't able to > cope with __meminit's changing semantics. > > When CONFIG_MEMORY_HOTPLUG=y references from .text to .meminit.text > should be allowed, because they're just folded in together in the linker > script. > > When CONFIG_MEMORY_HOTPLUG=n references from .text to .meminit.text > should NOT be allowed, because .meminit.text becomes .init.text and will > be freed. > > I don't see anything in the section mismatch logic to cope with that > difference. > > It looks like __meminit is saving us about 1K on powerpc, so I'm > strongly inclined to just remove it entirely from arch/powerpc. Gah that doesn't work. Our arch routines call things in mm/ that are __meminit, so we have to mark our code __meminit too, otherwise we get a section mismatch warning. cheers