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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4509AC4321E for ; Wed, 30 Nov 2022 22:38:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229662AbiK3WiA (ORCPT ); Wed, 30 Nov 2022 17:38:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229555AbiK3Wh7 (ORCPT ); Wed, 30 Nov 2022 17:37:59 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10EC643848; Wed, 30 Nov 2022 14:37:59 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A0A1C61E0F; Wed, 30 Nov 2022 22:37:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57F59C433D6; Wed, 30 Nov 2022 22:37:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669847878; bh=wBJggPu6LEiCX32dXU3wBuz4z4f1m5wgizBQVClgrRs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sdfn9F8Y5LEqFHHvrUouhm7+w7eSEiFZ9qjZWrfNiVQtQD///hEuuxYZYQsc1hbA0 2XX1vOYwmtw/z6cK5q7L6gM2xrzM4+RkCr3Yfljj+JJPxFtHVZXl01IJzy1CLRsnfC lSfM0zUG3rdwU6ZRrkEElKs4vOvf9ZLpdPHs3oG2ZucB7EaXxOhpDcE5JsxIMqudyn BpUQWM1xP2K/XbjyKfgmmbsxV7xOjf7GY7QO+1J2LuFRG6YuOOc3EU5ILfvxZWa3Hr ibsdMVYTuuckkvJVNMWzbBwTPnAUFskagqWh+aiZYH/foPZNCERQUEzHlmDOvun6oF 4amgxs2OjihSA== Date: Wed, 30 Nov 2022 15:37:55 -0700 From: Nathan Chancellor To: Masahiro Yamada Cc: Nick Desaulniers , Tom Rix , Nicolas Schier , Sami Tolvanen , Vincent Donnefort , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, patches@lists.linux.dev, Steffen Klassert , Daniel Jordan , linux-crypto@vger.kernel.org Subject: Re: [PATCH 1/2] padata: Do not mark padata_mt_helper() as __init Message-ID: References: <20221129190123.872394-1-nathan@kernel.org> <20221129190123.872394-2-nathan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org On Thu, Dec 01, 2022 at 07:20:47AM +0900, Masahiro Yamada wrote: > On Wed, Nov 30, 2022 at 4:02 AM Nathan Chancellor wrote: > > > > When building arm64 allmodconfig + ThinLTO with clang and a proposed > > modpost update to account for -ffuncton-sections, the following warning > > appears: > > > > How to enable -ffuncton-sections for ARCH=arm64 ? > (in other words, how to set CONFIG_LD_DEAD_CODE_DATA_ELIMINATION ?) clang LTO implies -fdata-sections and -ffunction-sections. $ cat foo.c int foo(void) { return 0; } $ cat bar.c extern int foo(void); int bar(void) { return foo(); } $ clang -c -o foo.{o,c} $ clang -c -o bar.{o,c} $ ld.lld -r -o foobar {foo,bar}.o $ llvm-readelf -s foobar Symbol table '.symtab' contains 9 entries: Num: Value Size Type Bind Vis Ndx Name 0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND 1: 0000000000000000 0 FILE LOCAL DEFAULT ABS foo.c 2: 0000000000000000 0 SECTION LOCAL DEFAULT 1 .text 3: 0000000000000000 0 SECTION LOCAL DEFAULT 3 .eh_frame 4: 0000000000000000 0 SECTION LOCAL DEFAULT 5 .llvm_addrsig 5: 0000000000000000 0 FILE LOCAL DEFAULT ABS bar.c 6: 0000000000000000 0 SECTION LOCAL DEFAULT 2 .comment 7: 0000000000000000 8 FUNC GLOBAL DEFAULT 1 foo 8: 0000000000000010 11 FUNC GLOBAL DEFAULT 1 bar $ clang -flto -c -o foo.{o,c} $ clang -flto -c -o bar.{o,c} $ ld.lld -r -o foobar {foo,bar}.o $ llvm-readelf -s foobar Symbol table '.symtab' contains 10 entries: Num: Value Size Type Bind Vis Ndx Name 0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND 1: 0000000000000000 0 FILE LOCAL DEFAULT ABS ld-temp.o 2: 0000000000000000 0 SECTION LOCAL DEFAULT 1 .text 3: 0000000000000000 0 SECTION LOCAL DEFAULT 2 .text.foo 4: 0000000000000000 0 SECTION LOCAL DEFAULT 3 .text.bar 5: 0000000000000000 0 SECTION LOCAL DEFAULT 6 .eh_frame 6: 0000000000000000 0 SECTION LOCAL DEFAULT 8 .llvm_addrsig 7: 0000000000000000 0 SECTION LOCAL DEFAULT 5 .comment 8: 0000000000000000 8 FUNC GLOBAL DEFAULT 2 foo 9: 0000000000000000 13 FUNC GLOBAL DEFAULT 3 bar > In upstream, it is only possible for mips and powerpc. > > ./arch/mips/Kconfig:82: select HAVE_LD_DEAD_CODE_DATA_ELIMINATION > ./arch/powerpc/Kconfig:237: select HAVE_LD_DEAD_CODE_DATA_ELIMINATION > > > > Is there another proposal to add it for arm64, > or is this about a downstream kernel? > > > > > > > > > WARNING: modpost: vmlinux.o: section mismatch in reference: padata_work_init (section: .text.padata_work_init) -> padata_mt_helper (section: .init.text) > > WARNING: modpost: vmlinux.o: section mismatch in reference: padata_work_init (section: .text.padata_work_init) -> padata_mt_helper (section: .init.text) > > > > In both cases, an __init function calls padata_work_init(), which is not > > marked __init, with padata_mt_helper(), another __init function, as a > > work function argument. > > > > padata_work_init() is called from non-init paths, otherwise it could be > > marked __init to resolve the warning. Instead, remove __init from > > padata_mt_helper() to resolve the warning. > > > > Signed-off-by: Nathan Chancellor > > --- > > Cc: Steffen Klassert > > Cc: Daniel Jordan > > Cc: linux-crypto@vger.kernel.org > > --- > > kernel/padata.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/kernel/padata.c b/kernel/padata.c > > index e5819bb8bd1d..c2271d7e446d 100644 > > --- a/kernel/padata.c > > +++ b/kernel/padata.c > > @@ -45,7 +45,7 @@ struct padata_mt_job_state { > > }; > > > > static void padata_free_pd(struct parallel_data *pd); > > -static void __init padata_mt_helper(struct work_struct *work); > > +static void padata_mt_helper(struct work_struct *work); > > > > static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index) > > { > > @@ -425,7 +425,7 @@ static int padata_setup_cpumasks(struct padata_instance *pinst) > > return err; > > } > > > > -static void __init padata_mt_helper(struct work_struct *w) > > +static void padata_mt_helper(struct work_struct *w) > > { > > struct padata_work *pw = container_of(w, struct padata_work, pw_work); > > struct padata_mt_job_state *ps = pw->pw_data; > > -- > > 2.38.1 > > > > > -- > Best Regards > Masahiro Yamada