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 7CD7CC43457 for ; Fri, 9 Oct 2020 16:15:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3937D2227E 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 S2389704AbgJIQPG (ORCPT ); Fri, 9 Oct 2020 12:15:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41480 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389766AbgJIQOU (ORCPT ); Fri, 9 Oct 2020 12:14:20 -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 BAA28C0613A9 for ; Fri, 9 Oct 2020 09:14:13 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id n13so9316923ybk.9 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=rqs/qpLSL8c3XqtI+LMYxgvkYUoYtU/Xk1yjf36kEBWRSR/BqDrQMgVjEtlYZc1BWR d8HxAPiPcpjX3CbHyAQTcWP6HQgfOBz9SQFiJ0apYpEtEaFLvpAs0i0T1iHL8mcYhjbn 3FbSa2AAFKxPapSGh/Vz9UMYxpyJ4aZU22uLw7Vuh7tBHN5xZ90USmKvifH86osSMD+y tPg4LuaNBYS3vM5Uhm3KjPlhSHLr/30TyFMaMSLo1QUvKBXjGK+YmQlHaSAknw2I01NZ K1VuJ2nTt0NOM73P641e27o1N3O7VpJJFXO4uMO+S8YMi+V7iHRQ8gr8G0z2389pQCgH i8Ww== X-Gm-Message-State: AOAM533P1ur0w16j3bhCg6Gx/UdOzmAP4N6YZHR1uUMINzLcSV2Hmzcj SrGbxyJQOGEYwe9zFYyz1Gu+S7RmOJQM8eU1swE= 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-pci@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