From patchwork Wed Feb 16 13:13:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 12748529 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38FC7C4332F for ; Wed, 16 Feb 2022 13:18:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234084AbiBPNSR (ORCPT ); Wed, 16 Feb 2022 08:18:17 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:36092 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233958AbiBPNRa (ORCPT ); Wed, 16 Feb 2022 08:17:30 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EAB2B64C0; Wed, 16 Feb 2022 05:17:16 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 55A28CE26F4; Wed, 16 Feb 2022 13:17:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F2C4C340F9; Wed, 16 Feb 2022 13:17:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645017433; bh=XYviTV8III28kBrCQmsfuK51xOc09ZOif7iEHrUTuIg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RtZeNhuMWLMdUCgp7sQPtFKueCz8UIMqyfmOJ7eTRpRAZj+EX1IydRbAp51tHxwWq 5ne2vxMm/JuLMAmzyha4cuHaIahixOHFYVc5gGcfZri8EF8XqsDBKKhTiX2FVDpISR Pagw3akqo4xNGkF8Pb3UNLVmcr6ZFwFviZKx75YteMrlQ/LSVcu+z3apLlbK8geLHf v3iSy1y9VzaMo/+yVZXWf0Swp3oDEXhPv7eE6oQXabEKWYYUYMRDAqB7mO4dBnJnsi bzLr4K/tjkFnSoB/60v9gCoDQiRG0gDzcN5E85Rk8eBnmYUibpTvgJRV9oTUxC2Xso Mffr2yyPA6wPQ== From: Arnd Bergmann To: Linus Torvalds , Christoph Hellwig , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, arnd@arndb.de, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk Cc: linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, geert@linux-m68k.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, green.hu@gmail.com, dinguyen@kernel.org, shorne@gmail.com, deller@gmx.de, mpe@ellerman.id.au, peterz@infradead.org, mingo@redhat.com, mark.rutland@arm.com, hca@linux.ibm.com, dalias@libc.org, davem@davemloft.net, richard@nod.at, x86@kernel.org, jcmvbkbc@gmail.com, ebiederm@xmission.com, akpm@linux-foundation.org, ardb@kernel.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org Subject: [PATCH v2 09/18] mips: use simpler access_ok() Date: Wed, 16 Feb 2022 14:13:23 +0100 Message-Id: <20220216131332.1489939-10-arnd@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20220216131332.1489939-1-arnd@kernel.org> References: <20220216131332.1489939-1-arnd@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org From: Arnd Bergmann Before unifying the mips version of __access_ok() with the generic code, this converts it to the same algorithm. This is a change in behavior on mips64, as now address in the user segment, the lower 2^62 bytes, is taken to be valid, relying on a page fault for addresses that are within that segment but not valid on that CPU. The new version should be the most effecient way to do this, but it gets rid of the special handling for size=0 that most other architectures ignore as well. Signed-off-by: Arnd Bergmann --- arch/mips/include/asm/uaccess.h | 22 ++++------------------ 1 file changed, 4 insertions(+), 18 deletions(-) diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h index db9a8e002b62..d7c89dc3426c 100644 --- a/arch/mips/include/asm/uaccess.h +++ b/arch/mips/include/asm/uaccess.h @@ -19,6 +19,7 @@ #ifdef CONFIG_32BIT #define __UA_LIMIT 0x80000000UL +#define TASK_SIZE_MAX __UA_LIMIT #define __UA_ADDR ".word" #define __UA_LA "la" @@ -33,6 +34,7 @@ extern u64 __ua_limit; #define __UA_LIMIT __ua_limit +#define TASK_SIZE_MAX XKSSEG #define __UA_ADDR ".dword" #define __UA_LA "dla" @@ -42,22 +44,6 @@ extern u64 __ua_limit; #endif /* CONFIG_64BIT */ -/* - * Is a address valid? This does a straightforward calculation rather - * than tests. - * - * Address valid if: - * - "addr" doesn't have any high-bits set - * - AND "size" doesn't have any high-bits set - * - AND "addr+size" doesn't have any high-bits set - * - OR we are in kernel mode. - * - * __ua_size() is a trick to avoid runtime checking of positive constant - * sizes; for those we already know at compile time that the size is ok. - */ -#define __ua_size(size) \ - ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size)) - /* * access_ok: - Checks if a user space pointer is valid * @addr: User space pointer to start of block to check @@ -79,9 +65,9 @@ extern u64 __ua_limit; static inline int __access_ok(const void __user *p, unsigned long size) { unsigned long addr = (unsigned long)p; - unsigned long end = addr + size - !!size; + unsigned long limit = TASK_SIZE_MAX; - return (__UA_LIMIT & (addr | end | __ua_size(size))) == 0; + return (size <= limit) && (addr <= (limit - size)); } #define access_ok(addr, size) \