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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C084AC433FE for ; Wed, 23 Feb 2022 23:31:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244815AbiBWXbe (ORCPT ); Wed, 23 Feb 2022 18:31:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52426 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243948AbiBWXbc (ORCPT ); Wed, 23 Feb 2022 18:31:32 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C8D58583B6; Wed, 23 Feb 2022 15:31:03 -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 ams.source.kernel.org (Postfix) with ESMTPS id 71131B81878; Wed, 23 Feb 2022 23:31:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 62A8BC340E7; Wed, 23 Feb 2022 23:30:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645659061; bh=lqCEQ++vi7cgL8SGDqvu6VRtg8aruPJlQBSjPBXBFVM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=sbRe9FkUPCxCGG5QhSpQFHALisL4a0h67bCxhSLbAt1nLiwP1yIOk1Uj7FSa6KCb5 weBLktMX2iJ1azUVoI5qzyIPsB248hdzJqK4FY8iQs4ijX9ClxGFEG4dPQ2t94Tu+v xnm83JKO7FsjVlGtupBZVZ1sGqkMArGtNnLjnEwqgMRRugYsRTn+yfOLhixpTMveFC hFyJk7dTbBRw3IsZy86rcTOonVkHxoMQs0BGW96T4vsXyVidvkbPH0uwFh8RFITz5K oD3k8dsNBCQPOLOspB8IOHbjF16KCCmPClOP9aOj20bxN2gTg9NdvWcdAxevymW0xQ hD4A1zZdc89kw== Message-ID: Date: Wed, 23 Feb 2022 17:30:53 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v2 07/18] nios2: drop access_ok() check from __put_user() Content-Language: en-US To: Arnd Bergmann , 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, 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 References: <20220216131332.1489939-1-arnd@kernel.org> <20220216131332.1489939-8-arnd@kernel.org> From: Dinh Nguyen In-Reply-To: <20220216131332.1489939-8-arnd@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On 2/16/22 07:13, Arnd Bergmann wrote: > From: Arnd Bergmann > > Unlike other architectures, the nios2 version of __put_user() has an > extra check for access_ok(), preventing it from being used to implement > __put_kernel_nofault(). > > Split up put_user() along the same lines as __get_user()/get_user() > > Signed-off-by: Arnd Bergmann > --- > arch/nios2/include/asm/uaccess.h | 56 +++++++++++++++++++------------- > 1 file changed, 33 insertions(+), 23 deletions(-) > > diff --git a/arch/nios2/include/asm/uaccess.h b/arch/nios2/include/asm/uaccess.h > index ca9285a915ef..a5cbe07cf0da 100644 > --- a/arch/nios2/include/asm/uaccess.h > +++ b/arch/nios2/include/asm/uaccess.h > @@ -167,34 +167,44 @@ do { \ > : "r" (val), "r" (ptr), "i" (-EFAULT)); \ > } > > -#define put_user(x, ptr) \ > +#define __put_user_common(__pu_val, __pu_ptr) \ > ({ \ > long __pu_err = -EFAULT; \ > - __typeof__(*(ptr)) __user *__pu_ptr = (ptr); \ > - __typeof__(*(ptr)) __pu_val = (__typeof(*ptr))(x); \ > - if (access_ok(__pu_ptr, sizeof(*__pu_ptr))) { \ > - switch (sizeof(*__pu_ptr)) { \ > - case 1: \ > - __put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err); \ > - break; \ > - case 2: \ > - __put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err); \ > - break; \ > - case 4: \ > - __put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err); \ > - break; \ > - default: \ > - /* XXX: This looks wrong... */ \ > - __pu_err = 0; \ > - if (copy_to_user(__pu_ptr, &(__pu_val), \ > - sizeof(*__pu_ptr))) \ > - __pu_err = -EFAULT; \ > - break; \ > - } \ > + switch (sizeof(*__pu_ptr)) { \ > + case 1: \ > + __put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err); \ > + break; \ > + case 2: \ > + __put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err); \ > + break; \ > + case 4: \ > + __put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err); \ > + break; \ > + default: \ > + /* XXX: This looks wrong... */ \ > + __pu_err = 0; \ > + if (__copy_to_user(__pu_ptr, &(__pu_val), \ > + sizeof(*__pu_ptr))) \ > + __pu_err = -EFAULT; \ > + break; \ > } \ > __pu_err; \ > }) > > -#define __put_user(x, ptr) put_user(x, ptr) > +#define __put_user(x, ptr) \ > +({ \ > + __auto_type __pu_ptr = (ptr); \ > + typeof(*__pu_ptr) __pu_val = (typeof(*__pu_ptr))(x); \ > + __put_user_common(__pu_val, __pu_ptr); \ > +}) > + > +#define put_user(x, ptr) \ > +({ \ > + __auto_type __pu_ptr = (ptr); \ > + typeof(*__pu_ptr) __pu_val = (typeof(*__pu_ptr))(x); \ > + access_ok(__pu_ptr, sizeof(*__pu_ptr)) ? \ > + __put_user_common(__pu_val, __pu_ptr) : \ > + -EFAULT; \ > +}) > > #endif /* _ASM_NIOS2_UACCESS_H */ Acked-by: Dinh Nguyen