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=-22.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 B8276C4338F for ; Tue, 17 Aug 2021 13:22:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8BD0C60238 for ; Tue, 17 Aug 2021 13:22:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237445AbhHQNXP (ORCPT ); Tue, 17 Aug 2021 09:23:15 -0400 Received: from pegase2.c-s.fr ([93.17.235.10]:51239 "EHLO pegase2.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236040AbhHQNXO (ORCPT ); Tue, 17 Aug 2021 09:23:14 -0400 Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4GpsCM6FLvz9sTg; Tue, 17 Aug 2021 15:22:39 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 98tisP6h3gsf; Tue, 17 Aug 2021 15:22:39 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4GpsCM5FSnz9sTf; Tue, 17 Aug 2021 15:22:39 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 886B28B7C8; Tue, 17 Aug 2021 15:22:39 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id z9ArqeFHdXUY; Tue, 17 Aug 2021 15:22:39 +0200 (CEST) Received: from [192.168.4.90] (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 1BB008B7A9; Tue, 17 Aug 2021 15:22:39 +0200 (CEST) Subject: Re: [PATCH/RFC] powerpc/module_64: allow .init_array constructors to run To: Jan Stancek , mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, linuxppc-dev@lists.ozlabs.org Cc: linux-kernel@vger.kernel.org References: <920acea9aa18e4f2956581a8e158bdaa376fdf63.1629203945.git.jstancek@redhat.com> From: Christophe Leroy Message-ID: <0bef6f5d-5c2a-efd4-6281-1e66b1709479@csgroup.eu> Date: Tue, 17 Aug 2021 15:22:38 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <920acea9aa18e4f2956581a8e158bdaa376fdf63.1629203945.git.jstancek@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 17/08/2021 à 15:02, Jan Stancek a écrit : > gcov and kasan rely on compiler generated constructor code. > For modules, gcc-8 with gcov enabled generates .init_array section, > but on ppc64le it doesn't get executed. find_module_sections() never > finds .init_array section, because module_frob_arch_sections() renames > it to _init_array. > > Avoid renaming .init_array section, so do_mod_ctors() can use it. > > Cc: Michael Ellerman > Cc: Benjamin Herrenschmidt > Cc: Paul Mackerras > Cc: Christophe Leroy > Signed-off-by: Jan Stancek > --- > I wasn't able to trace the comment: > "We don't handle .init for the moment: rename to _init" Original patch there: https://github.com/mpe/linux-fullhistory/commit/d6ad6690aa72 > to original patch (it pre-dates .git). I'm not sure if it > still applies today, so I limited patch to .init_array. This > fixes gcov for modules for me on ppc64le 5.14.0-rc6. > > Renaming issue is also mentioned in kasan patches here: > https://patchwork.ozlabs.org/project/linuxppc-dev/cover/20210319144058.772525-1-dja@axtens > > arch/powerpc/kernel/module_64.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c > index 6baa676e7cb6..c604b13ea6bf 100644 > --- a/arch/powerpc/kernel/module_64.c > +++ b/arch/powerpc/kernel/module_64.c > @@ -299,8 +299,16 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr, > sechdrs[i].sh_size); > > /* We don't handle .init for the moment: rename to _init */ > - while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init"))) > + while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init"))) { > +#ifdef CONFIG_CONSTRUCTORS Please avoid #ifdefery as much as possible. I think here you can do: if (IS_ENABLED(CONFIG_CONSTRUCTORS) && strstr(secstrings + sechdrs[i].sh_name, ".init_array")) > + /* find_module_sections() needs .init_array intact */ > + if (strstr(secstrings + sechdrs[i].sh_name, > + ".init_array")) { No { } for single statements (See https://www.kernel.org/doc/html/latest/process/coding-style.html#placing-braces-and-spaces) > + break; > + } > +#endif > p[0] = '_'; > + } > > if (sechdrs[i].sh_type == SHT_SYMTAB) > dedotify((void *)hdr + sechdrs[i].sh_offset, >