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=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 26102C43467 for ; Fri, 9 Oct 2020 16:15:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E86D822281 for ; Fri, 9 Oct 2020 16:15:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="rDHTl2DO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389859AbgJIQPG (ORCPT ); Fri, 9 Oct 2020 12:15:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41544 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389699AbgJIQOU (ORCPT ); Fri, 9 Oct 2020 12:14:20 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B822AC0613E4 for ; Fri, 9 Oct 2020 09:14:13 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id c9so7418360ybs.8 for ; Fri, 09 Oct 2020 09:14:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=ljsItlz/aE0P1FDke8OIPGTsfsgvR6SCQ5aAaAr+FuY=; b=rDHTl2DOvEF5lAI8/1xgnH7ewQP7v+fy6WFg1GImMEetNzxgNOGQtQTgFVZA7nJz4m E/V9TlOXQo2zsXvADw6ZjNHpbyo0GyLXq/UcXFopFQ5iYAVttrLb5kwsOMZlNj6d3mq2 v2Z69HCANswfC9sVB06+DLebakWFduI4MBn43M/w9uUpWzAIbBGEejEK5mHvIYhz912n egyvp5xLTL8ReK004BgDAz4wuj45irBJ5zvwJmj0uVsXV1gk7BqZvJNpws7d45/nZF1s sv/UzaMr8Prok4UlE5mODVRqtzkXlZAlSECInu3Rk5zSafDWjBxTBOhp32r/igI3DisM FvIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ljsItlz/aE0P1FDke8OIPGTsfsgvR6SCQ5aAaAr+FuY=; b=rQBKlB1tUiWg8H8V98D0T+tyycMQGzq4lcxLvtJBoz5nohh24rPy8wqAkWklUvsW8L XeNjykgXBCt44cC7ab4cLb9X3SdCgXdk+JEm3mYgGEkzcLEv0BT2RDF2u56xskL2Rcue u8j48SqmSoHc9dhBXcCZbEqgI0giFpH6xh4k7Y5YqVl2h/FutxMvD6ZF4ep2q35R2c16 weCMvjyjHCtJR4dsqYGZkUZFJ3190uRzKwF6NdV0nQY33IRJ5yZud2/WHvwz+OuwO//H QynOvtyLb8l2QiRLo/+VCL0FCqnFcoHiqh02sXe7DkmqSBbNOiHWCOBCx850WeQg6lnj nuDw== X-Gm-Message-State: AOAM531Hqr4K8tWmQbe/MG08qYhgqbQx1jEJBJUPkmpelGTZDsVEAza7 6RMUOsinF0W3AV+docTT0cjVUoD21zap1ch45BY= X-Google-Smtp-Source: ABdhPJy32BlRlXtKX3ZecjjCx8sYUdqfwZnP6p3172X1KprlyJNmmCaj7qPqSsBQi7a3XNa21VFXuJCMRei9tPIgOic= Sender: "samitolvanen via sendgmr" X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:f693:9fff:fef4:1b6d]) (user=samitolvanen job=sendgmr) by 2002:a25:aaae:: with SMTP id t43mr18851419ybi.404.1602260052989; Fri, 09 Oct 2020 09:14:12 -0700 (PDT) Date: Fri, 9 Oct 2020 09:13:25 -0700 In-Reply-To: <20201009161338.657380-1-samitolvanen@google.com> Message-Id: <20201009161338.657380-17-samitolvanen@google.com> Mime-Version: 1.0 References: <20201009161338.657380-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.1011.ga647a8990f-goog Subject: [PATCH v5 16/29] init: lto: fix PREL32 relocations From: Sami Tolvanen To: Masahiro Yamada , Will Deacon , Steven Rostedt Cc: Peter Zijlstra , 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arch@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 Reviewed-by: Kees Cook --- include/linux/init.h | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/include/linux/init.h b/include/linux/init.h index af638cd6dd52..cea63f7e7705 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -209,26 +209,49 @@ 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); \ + 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)) -- 2.28.0.1011.ga647a8990f-goog