From patchwork Wed Jun 24 20:31:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11624243 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6CC78913 for ; Wed, 24 Jun 2020 20:34:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5437F20836 for ; Wed, 24 Jun 2020 20:34:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="egWHIaow" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406522AbgFXUdV (ORCPT ); Wed, 24 Jun 2020 16:33:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406477AbgFXUdR (ORCPT ); Wed, 24 Jun 2020 16:33:17 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17D51C061795 for ; Wed, 24 Jun 2020 13:33:17 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id b135so3498656yba.11 for ; Wed, 24 Jun 2020 13:33:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=edIkT6p07lpLePHQP+aYqsXpIzZ2+6woe9Vgp5gIJI4=; b=egWHIaowycA2j4XZam7KmKMW2pQ89pwKSamnnESmMZjXlGrpDiBMEKX0ymsIpEUG5Q Q/5jq7wq9EUsrGut0D7nH0OzX+X6PmQ4BsvV+OFdyIwItO18fwnnqRcjLL/etsokICn2 kJA/eOpcLnRws54bEMudJOUeKnPBfutms4HPc2YVoU7pUuEXirkoHEo/+ZivIPBIpcjm QAZkoUB6YhA3LjQHac3tKT7W83SDE0ybUBlgAkHod3lCaXJMmDghQ2Hjaer2BjebhMdJ 6tJB8nkEwUWILUX4LAlqgG6pcwYlTLpv3LHaWpmgIRcC8eGvhD6AT800VKeaZEkZUUaI CVRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=edIkT6p07lpLePHQP+aYqsXpIzZ2+6woe9Vgp5gIJI4=; b=ivctJc61TNiLl0B+66EKRpGc9gGKW04LkstPTdPwdjcIJTH+D6fckzbgO4EF6Nk5WN 3aSM6/Mubr0Id3TUp1zkJLV29B3rKS3wfZsfyf9wCzws6ZuMtygvmlzadICpyFzNcP0g Du45mcK4R1xb3bVeIvg4PfgLfO4LzBSpFDZqXTtezamC7+iqXT1OiI05klnTl5xxy/wC rNhgFZ8vdzqiwqNtok1qBInIozlozzNkqFRA0bQVEQT9UZkbh8JIhLuigNQlntGoU/EZ 1c99Os/vzL5fndDrFapAKCo0G593ZXffp/qcIFmeLDKe8A1NjlQ9Mma6bantitgMp1Ya 2MKg== X-Gm-Message-State: AOAM532Y26ZmWAQPD/t/3dE6qvioiy6fbrKDoa0r71YcV2dG/+csy8an 1VuWEpL791dqIPTNZFLisFqg1PDGc7hxoWoUD5c= X-Google-Smtp-Source: ABdhPJydy+dzRZtnkDF9CbEhIOBTVruIEpnrPFlxeYrxbEJR+QigE4MSYlaU55SmzK1okb/YgyaF3Z/PviJDUt9UdRg= X-Received: by 2002:a25:2fc5:: with SMTP id v188mr45630243ybv.130.1593030796295; Wed, 24 Jun 2020 13:33:16 -0700 (PDT) Date: Wed, 24 Jun 2020 13:31:48 -0700 In-Reply-To: <20200624203200.78870-1-samitolvanen@google.com> Message-Id: <20200624203200.78870-11-samitolvanen@google.com> Mime-Version: 1.0 References: <20200624203200.78870-1-samitolvanen@google.com> X-Mailer: git-send-email 2.27.0.212.ge8ba1cc988-goog Subject: [PATCH 10/22] init: lto: fix PREL32 relocations From: Sami Tolvanen To: Masahiro Yamada , Will Deacon Cc: Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, x86@kernel.org, Sami Tolvanen Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org With LTO, the compiler can rename static functions to avoid global naming collisions. As initcall functions are typically static, renaming can break references to them in inline assembly. This change adds a global stub with a stable name for each initcall to fix the issue when PREL32 relocations are used. Signed-off-by: Sami Tolvanen --- include/linux/init.h | 30 ++++++++++++++++++++++++++---- 1 file changed, 26 insertions(+), 4 deletions(-) diff --git a/include/linux/init.h b/include/linux/init.h index af638cd6dd52..5b4bdc5a8399 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -209,26 +209,48 @@ extern bool initcall_debug; */ #define __initcall_section(__sec, __iid) \ #__sec ".init.." #__iid + +/* + * With LTO, the compiler can rename static functions to avoid + * global naming collisions. We use a global stub function for + * initcalls to create a stable symbol name whose address can be + * taken in inline assembly when PREL32 relocations are used. + */ +#define __initcall_stub(fn, __iid, id) \ + __initcall_name(initstub, __iid, id) + +#define __define_initcall_stub(__stub, fn) \ + int __init __stub(void) \ + { \ + return fn(); \ + } \ + __ADDRESSABLE(__stub) #else #define __initcall_section(__sec, __iid) \ #__sec ".init" + +#define __initcall_stub(fn, __iid, id) fn + +#define __define_initcall_stub(__stub, fn) \ + __ADDRESSABLE(fn) #endif #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS -#define ____define_initcall(fn, __name, __sec) \ - __ADDRESSABLE(fn) \ +#define ____define_initcall(fn, __stub, __name, __sec) \ + __define_initcall_stub(__stub, fn) \ asm(".section \"" __sec "\", \"a\" \n" \ __stringify(__name) ": \n" \ - ".long " #fn " - . \n" \ + ".long " __stringify(__stub) " - . \n" \ ".previous \n"); #else -#define ____define_initcall(fn, __name, __sec) \ +#define ____define_initcall(fn, __unused, __name, __sec) \ static initcall_t __name __used \ __attribute__((__section__(__sec))) = fn; #endif #define __unique_initcall(fn, id, __sec, __iid) \ ____define_initcall(fn, \ + __initcall_stub(fn, __iid, id), \ __initcall_name(initcall, __iid, id), \ __initcall_section(__sec, __iid))