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=ham 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 635E8C433DF for ; Tue, 13 Oct 2020 00:34:53 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 9E335206B5 for ; Tue, 13 Oct 2020 00:34:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="oum/rjpL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9E335206B5 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-20189-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 17628 invoked by uid 550); 13 Oct 2020 00:32:53 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 17549 invoked from network); 13 Oct 2020 00:32:52 -0000 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=oum/rjpLgBIXRzOc38bbhKmbjYdpUPokaueoFkr6scrVzuU9bSims44TwDZ3YQ5/wo tyFgp4XcVUbaCRTIJ7WyMGcJzX9IUYyY8SHh85axKohx3B9YKTYssK7rD/sd+9Gs6OYS 5pLTO9ddpancYtucgKle3gEvEszXKuKKjECSTrvhHvUa0sTQkJ9oAv6nDZgXB2iqzs6F HaozULUdcqCQOaO/g6JRs136BCvSZm6oYr/J1aF/vZtIWA1niCkH+rLYrArccBedjSyb 5JHkueqtTR75zT9X9nD843dXt6Ntpa7oVvhDLRM/xKFRBTH7orAGCLXgpiwYxg5ODzqW hhPg== 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=Ic9fimd0OPmJx53zRLSjSEv3wGnZtenFEbxHCfyjRgVez1dsCwwDHurGxeP+nPCWtb Kx8RW6bR3i9lqslnkjktaD8w+TscfQOLsxhvyIuYMtiEGR300I2t7mbUmPMQnLTK6l25 4qeKUgNYCSYRhUMQeTRxl/6YAAncanOD9vWqOz4O+aapTJd9kcDbJLcl2HixXWUUsf7g ae8EXrjNND92JO0u2cegBwC2yAFnMT0OwzkmTL4kgvUf51jtq/YN1M5etZYwNUj0i+Es z3/omGfH0cFd9QpSK8GnorjaKgoA7JVWIF8n7kLIpMDYIW7k6MjKhMBMiZBiRllkcEqO tvIg== X-Gm-Message-State: AOAM5315Mmi0o6S/hbnxsfrWzjiWTvyiIzLeF+gjA+pj2BTxsFFHaMJI jWA+T+6ehDIpCj65qecZB2xG9g67AccnYq8o8/Q= X-Google-Smtp-Source: ABdhPJwD9pFtxRfETVm7J2JNUfN/ppBHwqDfCtEerXB7/Jkt+07t8oFntbLZxmanhpG4ZYrTFeVoYv7CKCtYGxrwXzg= 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:a25:37c2:: with SMTP id e185mr20091375yba.401.1602549160656; Mon, 12 Oct 2020 17:32:40 -0700 (PDT) Date: Mon, 12 Oct 2020 17:31:54 -0700 In-Reply-To: <20201013003203.4168817-1-samitolvanen@google.com> Message-Id: <20201013003203.4168817-17-samitolvanen@google.com> Mime-Version: 1.0 References: <20201013003203.4168817-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.1011.ga647a8990f-goog Subject: [PATCH v6 16/25] init: lto: fix PREL32 relocations From: Sami Tolvanen To: Masahiro Yamada , Steven Rostedt Cc: Will Deacon , 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" 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