From patchwork Tue Dec 13 18:35:28 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 13072322 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 D9570C4708D for ; Tue, 13 Dec 2022 18:36:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236616AbiLMSgL (ORCPT ); Tue, 13 Dec 2022 13:36:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236626AbiLMSfv (ORCPT ); Tue, 13 Dec 2022 13:35:51 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F26425289; Tue, 13 Dec 2022 10:35:50 -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 88B4F616D1; Tue, 13 Dec 2022 18:35:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34509C433F1; Tue, 13 Dec 2022 18:35:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670956550; bh=iyMWYw8QwA65vOGqJNqBD5pQyIoP0C216Ve7ERqMbKs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZIw+ieQH9eUqCDx7a1A0RVho7mXVxIo8vFgNcKm7CnBOORxhuWpTWR9X/jQZhvOq7 ZOrNQfJDtYODAEwbxMsXi6X+oEGXYUw94sc59zvn5qPg/fHOSS0Psa12wAcpfzlnDG 9Gzqw+DDcKJIuT9SukGEFtJtDQuwO+I4Uf75onM1Pt22Lukw67l+QYw92d6k+9IiTz wIgDbNtVQn3TSPywWnziFudu4t8zh21521aqykMgOG+Bp6rDF/pgIyEde37GbEktV6 9y3JUMV1I0pBqA2OzuzeQizcOz7ckQIBfwv9ngrrla3lxq7MDHOEd5K33r3jNFlI5l alCZcyTHvGUYA== 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, Nathan Chancellor , Daniel Jordan , Steffen Klassert , linux-crypto@vger.kernel.org Subject: [PATCH v3 1/2] padata: Mark padata_work_init() as __ref Date: Tue, 13 Dec 2022 11:35:28 -0700 Message-Id: <20221213183529.766630-2-nathan@kernel.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221213183529.766630-1-nathan@kernel.org> References: <20221213183529.766630-1-nathan@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org When building arm64 allmodconfig + ThinLTO with clang and a proposed modpost update to account for -ffuncton-sections, the following warning appears: 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) LLVM has optimized padata_work_init() to include the address of padata_mt_helper() directly because it inlined the other call to padata_work_init() with padata_parallel_worker(), meaning the remaining uses of padata_work_init() use padata_mt_helper() as the work_fn argument. This optimization causes modpost to complain since padata_work_init() is not __init, whereas padata_mt_helper() is. Since padata_work_init() is only called from __init code when padata_mt_helper() is passed as the work_fn argument, mark padata_work_init() as __ref, which makes it clear to modpost that this scenario is okay. Suggested-by: Daniel Jordan Signed-off-by: Nathan Chancellor --- Cc: Steffen Klassert Cc: Daniel Jordan Cc: linux-crypto@vger.kernel.org --- kernel/padata.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/padata.c b/kernel/padata.c index e5819bb8bd1d..d175cc000453 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -83,8 +83,16 @@ static struct padata_work *padata_work_alloc(void) return pw; } -static void padata_work_init(struct padata_work *pw, work_func_t work_fn, - void *data, int flags) +/* + * This function is marked __ref because this function may be optimized in such + * a way that it directly refers to work_fn's address, which causes modpost to + * complain when work_fn is marked __init. This scenario was observed with clang + * LTO, where padata_work_init() was optimized to refer directly to + * padata_mt_helper() because the calls to padata_work_init() with other work_fn + * values were eliminated or inlined. + */ +static void __ref padata_work_init(struct padata_work *pw, work_func_t work_fn, + void *data, int flags) { if (flags & PADATA_WORK_ONSTACK) INIT_WORK_ONSTACK(&pw->pw_work, work_fn);