From patchwork Tue Jan 28 14:05:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 11354441 X-Patchwork-Delegate: paulburton@kernel.org 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 DACEE92A for ; Tue, 28 Jan 2020 14:43:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFC8224685 for ; Tue, 28 Jan 2020 14:43:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580222582; bh=bQ7Ch7w2vy4MOIB1WFMg92oKjuy8tP+9iUlBmjabkBE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=wjD2rpcYcdqCmTTqIr1FkLTvqMkpHIkzeZmAS66oynF/4ph1POR983szL+kOzDa79 jmpSrjH8Zjgi+4J7BmnSHz9VEn9yHZ6eWDQNV7Dc8SD4E/9l+WnvuF9m3DWDHzmPJt kdbh891TXT5YN9/sCNzeeGhEzD7ZgYDtEAE9kThw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729212AbgA1OMS (ORCPT ); Tue, 28 Jan 2020 09:12:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:33450 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727397AbgA1OMO (ORCPT ); Tue, 28 Jan 2020 09:12:14 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3305224685; Tue, 28 Jan 2020 14:12:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580220733; bh=bQ7Ch7w2vy4MOIB1WFMg92oKjuy8tP+9iUlBmjabkBE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cB7ACNL6yJeWog2gNufa3+2u0rTWF8vnYdDqj83Jg6sh30t2cEO7aLHKv0xIwu2gp hEksI83hwcjrQPGYgAQlaCJFzpnoF8gA2sWAiiflDoImlNHAsdRecyGPJBob8Lr4Zk 0F76pdmQQBxMPbS+vhXK5xxKDFkVOAO2NYWoLF2k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nathan Chancellor , Eli Friedman , Nick Desaulniers , Paul Burton , ralf@linux-mips.org, jhogan@kernel.org, "Maciej W. Rozycki" , Hassan Naveed , Stephen Kitt , Serge Semin , Mike Rapoport , Andrew Morton , Michal Hocko , linux-mips@vger.kernel.org, clang-built-linux@googlegroups.com, Sasha Levin Subject: [PATCH 4.4 126/183] mips: avoid explicit UB in assignment of mips_io_port_base Date: Tue, 28 Jan 2020 15:05:45 +0100 Message-Id: <20200128135842.463604020@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200128135829.486060649@linuxfoundation.org> References: <20200128135829.486060649@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org From: Nick Desaulniers [ Upstream commit 12051b318bc3ce5b42d6d786191008284b067d83 ] The code in question is modifying a variable declared const through pointer manipulation. Such code is explicitly undefined behavior, and is the lone issue preventing malta_defconfig from booting when built with Clang: If an attempt is made to modify an object defined with a const-qualified type through use of an lvalue with non-const-qualified type, the behavior is undefined. LLVM is removing such assignments. A simple fix is to not declare variables const that you plan on modifying. Limiting the scope would be a better method of preventing unwanted writes to such a variable. Further, the code in question mentions "compiler bugs" without any links to bug reports, so it is difficult to know if the issue is resolved in GCC. The patch was authored in 2006, which would have been GCC 4.0.3 or 4.1.1. The minimal supported version of GCC in the Linux kernel is currently 4.6. For what its worth, there was UB before the commit in question, it just added a barrier and got lucky IRT codegen. I don't think there's any actual compiler bugs related, just runtime bugs due to UB. Link: https://github.com/ClangBuiltLinux/linux/issues/610 Fixes: 966f4406d903 ("[MIPS] Work around bad code generation for .") Reported-by: Nathan Chancellor Debugged-by: Nathan Chancellor Suggested-by: Eli Friedman Signed-off-by: Nick Desaulniers Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Signed-off-by: Paul Burton Cc: ralf@linux-mips.org Cc: jhogan@kernel.org Cc: Maciej W. Rozycki Cc: Hassan Naveed Cc: Stephen Kitt Cc: Serge Semin Cc: Mike Rapoport Cc: Andrew Morton Cc: Michal Hocko Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: clang-built-linux@googlegroups.com Signed-off-by: Sasha Levin --- arch/mips/include/asm/io.h | 14 ++------------ arch/mips/kernel/setup.c | 2 +- 2 files changed, 3 insertions(+), 13 deletions(-) diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h index ab1df19b09571..60604b26fa72c 100644 --- a/arch/mips/include/asm/io.h +++ b/arch/mips/include/asm/io.h @@ -60,21 +60,11 @@ * instruction, so the lower 16 bits must be zero. Should be true on * on any sane architecture; generic code does not use this assumption. */ -extern const unsigned long mips_io_port_base; +extern unsigned long mips_io_port_base; -/* - * Gcc will generate code to load the value of mips_io_port_base after each - * function call which may be fairly wasteful in some cases. So we don't - * play quite by the book. We tell gcc mips_io_port_base is a long variable - * which solves the code generation issue. Now we need to violate the - * aliasing rules a little to make initialization possible and finally we - * will need the barrier() to fight side effects of the aliasing chat. - * This trickery will eventually collapse under gcc's optimizer. Oh well. - */ static inline void set_io_port_base(unsigned long base) { - * (unsigned long *) &mips_io_port_base = base; - barrier(); + mips_io_port_base = base; } /* diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index 4f9f1ae492138..fadc946b306d2 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -80,7 +80,7 @@ static char __initdata builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE; * mips_io_port_base is the begin of the address space to which x86 style * I/O ports are mapped. */ -const unsigned long mips_io_port_base = -1; +unsigned long mips_io_port_base = -1; EXPORT_SYMBOL(mips_io_port_base); static struct resource code_resource = { .name = "Kernel code", }; From patchwork Tue Jan 28 14:06:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 11354415 X-Patchwork-Delegate: paulburton@kernel.org 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 2669D92A for ; Tue, 28 Jan 2020 14:41:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04EE024699 for ; Tue, 28 Jan 2020 14:41:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580222468; bh=ovyg9rOdRhnWjAyCJAiP7l4cs3HUvteGl44V31baW5Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gAFSKoZTHyvuvCrP0FTjtDnJkDhO75sWqL1TSAUuq8uc5jVoepLj4cnGAzxOsLjl8 v6uK5P+EY3gJmvMEWq45CfeHhmdh4BY8F7DSJhaOqUtH5erAsx72CbuJQf8JiYEzAz USnAIhTkuM885J+qc6IKXohVHG0jIPLcHPzY2Lwg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729632AbgA1OlH (ORCPT ); Tue, 28 Jan 2020 09:41:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:36662 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729359AbgA1OOb (ORCPT ); Tue, 28 Jan 2020 09:14:31 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3A39D2468A; Tue, 28 Jan 2020 14:14:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580220870; bh=ovyg9rOdRhnWjAyCJAiP7l4cs3HUvteGl44V31baW5Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dc9ulyBrkIHCuMgkqpAtbP7Gjp+sJVBw3I/MBYYQGYBfOSqzDaO5Lx9tMquAy293m NGzV4Ja+3ufK/loKyivESR3XxxCJoHk2kb5kbBHfG1aou6AvuDoKx+bDi+hEkdosrQ gzhqbkQH19sbSGbWb4JRe6Gn67a+IHAt6ge/n0cg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tiezhu Yang , Paul Burton , Ralf Baechle , James Hogan , Huacai Chen , Jiaxun Yang , linux-mips@vger.kernel.org, Sasha Levin Subject: [PATCH 4.4 153/183] MIPS: Loongson: Fix return value of loongson_hwmon_init Date: Tue, 28 Jan 2020 15:06:12 +0100 Message-Id: <20200128135845.061700335@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200128135829.486060649@linuxfoundation.org> References: <20200128135829.486060649@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org From: Tiezhu Yang [ Upstream commit dece3c2a320b0a6d891da6ff774ab763969b6860 ] When call function hwmon_device_register failed, use the actual return value instead of always -ENOMEM. Fixes: 64f09aa967e1 ("MIPS: Loongson-3: Add CPU Hwmon platform driver") Signed-off-by: Tiezhu Yang Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: James Hogan Cc: Huacai Chen Cc: Jiaxun Yang Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Sasha Levin --- drivers/platform/mips/cpu_hwmon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/platform/mips/cpu_hwmon.c b/drivers/platform/mips/cpu_hwmon.c index 0f6c63e17049e..9a201c3caaf41 100644 --- a/drivers/platform/mips/cpu_hwmon.c +++ b/drivers/platform/mips/cpu_hwmon.c @@ -155,7 +155,7 @@ static int __init loongson_hwmon_init(void) cpu_hwmon_dev = hwmon_device_register(NULL); if (IS_ERR(cpu_hwmon_dev)) { - ret = -ENOMEM; + ret = PTR_ERR(cpu_hwmon_dev); pr_err("hwmon_device_register fail!\n"); goto fail_hwmon_device_register; }