From patchwork Mon Feb 14 16:34:42 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 12745846 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2496C433F5 for ; Mon, 14 Feb 2022 16:36:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3329B6B0080; Mon, 14 Feb 2022 11:36:34 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2E13F6B0081; Mon, 14 Feb 2022 11:36:34 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 15B436B0082; Mon, 14 Feb 2022 11:36:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0195.hostedemail.com [216.40.44.195]) by kanga.kvack.org (Postfix) with ESMTP id 07D9A6B0080 for ; Mon, 14 Feb 2022 11:36:34 -0500 (EST) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id B98158248D52 for ; Mon, 14 Feb 2022 16:36:33 +0000 (UTC) X-FDA: 79141938666.30.3394088 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf04.hostedemail.com (Postfix) with ESMTP id 2CD4E40019 for ; Mon, 14 Feb 2022 16:36:33 +0000 (UTC) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 85254614F3; Mon, 14 Feb 2022 16:36:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1DF5AC340EE; Mon, 14 Feb 2022 16:36:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644856592; bh=/86KMr0jNBuJ/zqhHefOXTiqAWO1yELIA3z6g/367IQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ju2iGesCRW+FUxlTNWTSRCgy2RFCuZmRYFpVLrljojp/Ih1OBpPciIhZmM3Mzx76Y pq5UVjX55O0F8EXS8TaAkyYpSzYdo5XnN3HUDTfqVZjd5Sxm+EgqhUJfUY0qFQsOiM WPe43LcxQCw3FNNhUfT3JoeBojFKSdpgkUg8J9I/dv80iMXlTOJQyVuvr1Ic44t/BW sshZLtCicnOONQZDNhIZJ2ShtALDJCGKaAWUcBcXH8Jbk1posHGnpQW7HLIfAPf8T5 5TP+rCS3n73O88MVkDoM2JLsZFfmsE0haaOo3bUAhntO+4hI+BH5xYhaxIiM5tV/MT +qH72eefIpddw== 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 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-arm-kernel@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 04/14] x86: use more conventional access_ok() definition Date: Mon, 14 Feb 2022 17:34:42 +0100 Message-Id: <20220214163452.1568807-5-arnd@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20220214163452.1568807-1-arnd@kernel.org> References: <20220214163452.1568807-1-arnd@kernel.org> MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 2CD4E40019 X-Stat-Signature: gz3gw5gkc6yowjmm98ggx9x56pasu7ax Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ju2iGesC; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf04.hostedemail.com: domain of arnd@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=arnd@kernel.org X-HE-Tag: 1644856593-65509 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Arnd Bergmann The way that access_ok() is defined on x86 is slightly different from most other architectures, and a bit more complex. The generic version tends to result in the best output on all architectures, as it results in single comparison against a constant limit for calls with a known size. There are a few callers of __range_not_ok(), all of which use TASK_SIZE as the limit rather than TASK_SIZE_MAX, but I could not see any reason for picking this. Changing these to call __access_ok() instead uses the default limit, but keeps the behavior otherwise. x86 is the only architecture with a WARN_ON_IN_IRQ() checking access_ok(), but it's probably best to leave that in place. Signed-off-by: Arnd Bergmann --- arch/x86/include/asm/uaccess.h | 38 +++++++++++----------------------- 1 file changed, 12 insertions(+), 26 deletions(-) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index ac96f9b2d64b..6956a63291b6 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -16,30 +16,13 @@ * Test whether a block of memory is a valid user space address. * Returns 0 if the range is valid, nonzero otherwise. */ -static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit) +static inline bool __access_ok(void __user *ptr, unsigned long size) { - /* - * If we have used "sizeof()" for the size, - * we know it won't overflow the limit (but - * it might overflow the 'addr', so it's - * important to subtract the size from the - * limit, not add it to the address). - */ - if (__builtin_constant_p(size)) - return unlikely(addr > limit - size); - - /* Arbitrary sizes? Be careful about overflow */ - addr += size; - if (unlikely(addr < size)) - return true; - return unlikely(addr > limit); -} + unsigned long limit = TASK_SIZE_MAX; + unsigned long addr = ptr; -#define __range_not_ok(addr, size, limit) \ -({ \ - __chk_user_ptr(addr); \ - __chk_range_not_ok((unsigned long __force)(addr), size, limit); \ -}) + return (size <= limit) && (addr <= (limit - size)); +} #ifdef CONFIG_DEBUG_ATOMIC_SLEEP static inline bool pagefault_disabled(void); @@ -66,12 +49,15 @@ static inline bool pagefault_disabled(void); * Return: true (nonzero) if the memory block may be valid, false (zero) * if it is definitely invalid. */ -#define access_ok(addr, size) \ -({ \ - WARN_ON_IN_IRQ(); \ - likely(!__range_not_ok(addr, size, TASK_SIZE_MAX)); \ +#define access_ok(addr, size) \ +({ \ + WARN_ON_IN_IRQ(); \ + likely(__access_ok(addr, size));\ }) +#define __range_not_ok(addr, size, limit) (!__access_ok(addr, size)) +#define __chk_range_not_ok(addr, size, limit) (!__access_ok((void __user *)addr, size)) + extern int __get_user_1(void); extern int __get_user_2(void); extern int __get_user_4(void);