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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 0FDB2C433E0 for ; Fri, 5 Feb 2021 02:33:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C9EE464E8C for ; Fri, 5 Feb 2021 02:33:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230263AbhBECdi (ORCPT ); Thu, 4 Feb 2021 21:33:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:45982 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230248AbhBECda (ORCPT ); Thu, 4 Feb 2021 21:33:30 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id D510064E8C; Fri, 5 Feb 2021 02:32:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1612492349; bh=zCb/7WAiBCDElm4qashemmfeIZSFHUythbcDbyDQ0bY=; h=Date:From:To:Subject:In-Reply-To:From; b=mqgP5hAv3U6KCM5XV3I8PuqIAozcJGrOEpwQaJMqGvg/Y8hKT2EjCYjZJf4fiSAxn 5n3nK4ENYH6DPnJoG0Mp5wwSdnP9WG/4qVJsYKiqz/tdNKgcZe+PQk/o5ENJeDkuPj YRMN5fgU+AsEkwPqzDPtre8w1euqTHIUezL4pl60= Date: Thu, 04 Feb 2021 18:32:28 -0800 From: Andrew Morton To: akpm@linux-foundation.org, arnd@arndb.de, jeyu@kernel.org, johannes.berg@intel.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, oberpar@linux.ibm.com, torvalds@linux-foundation.org Subject: [patch 08/18] init/gcov: allow CONFIG_CONSTRUCTORS on UML to fix module gcov Message-ID: <20210205023228.nBf0f2zDd%akpm@linux-foundation.org> In-Reply-To: <20210204183135.e123f0d6027529f2cf500cf2@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Johannes Berg Subject: init/gcov: allow CONFIG_CONSTRUCTORS on UML to fix module gcov On ARCH=um, loading a module doesn't result in its constructors getting called, which breaks module gcov since the debugfs files are never registered. On the other hand, in-kernel constructors have already been called by the dynamic linker, so we can't call them again. Get out of this conundrum by allowing CONFIG_CONSTRUCTORS to be selected, but avoiding the in-kernel constructor calls. Also remove the "if !UML" from GCOV selecting CONSTRUCTORS now, since we really do want CONSTRUCTORS, just not kernel binary ones. Link: https://lkml.kernel.org/r/20210120172041.c246a2cac2fb.I1358f584b76f1898373adfed77f4462c8705b736@changeid Signed-off-by: Johannes Berg Reviewed-by: Peter Oberparleiter Cc: Arnd Bergmann Cc: Jessica Yu Signed-off-by: Andrew Morton --- init/Kconfig | 1 - init/main.c | 8 +++++++- kernel/gcov/Kconfig | 2 +- 3 files changed, 8 insertions(+), 3 deletions(-) --- a/init/Kconfig~init-gcov-allow-config_constructors-on-uml-to-fix-module-gcov +++ a/init/Kconfig @@ -76,7 +76,6 @@ config CC_HAS_ASM_INLINE config CONSTRUCTORS bool - depends on !UML config IRQ_WORK bool --- a/init/main.c~init-gcov-allow-config_constructors-on-uml-to-fix-module-gcov +++ a/init/main.c @@ -1066,7 +1066,13 @@ asmlinkage __visible void __init __no_sa /* Call all constructor functions linked into the kernel. */ static void __init do_ctors(void) { -#ifdef CONFIG_CONSTRUCTORS +/* + * For UML, the constructors have already been called by the + * normal setup code as it's just a normal ELF binary, so we + * cannot do it again - but we do need CONFIG_CONSTRUCTORS + * even on UML for modules. + */ +#if defined(CONFIG_CONSTRUCTORS) && !defined(CONFIG_UML) ctor_fn_t *fn = (ctor_fn_t *) __ctors_start; for (; fn < (ctor_fn_t *) __ctors_end; fn++) --- a/kernel/gcov/Kconfig~init-gcov-allow-config_constructors-on-uml-to-fix-module-gcov +++ a/kernel/gcov/Kconfig @@ -4,7 +4,7 @@ menu "GCOV-based kernel profiling" config GCOV_KERNEL bool "Enable gcov-based kernel profiling" depends on DEBUG_FS - select CONSTRUCTORS if !UML + select CONSTRUCTORS default n help This option enables gcov-based code profiling (e.g. for code coverage _