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=-12.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 AC214C4741F for ; Fri, 30 Oct 2020 15:49:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 243B022243 for ; Fri, 30 Oct 2020 15:49:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="WVmWqQwG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 243B022243 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8D0286B0073; Fri, 30 Oct 2020 11:49:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 859886B0074; Fri, 30 Oct 2020 11:49:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 721F96B0075; Fri, 30 Oct 2020 11:49:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0202.hostedemail.com [216.40.44.202]) by kanga.kvack.org (Postfix) with ESMTP id 40DC36B0073 for ; Fri, 30 Oct 2020 11:49:32 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id D6088180AD804 for ; Fri, 30 Oct 2020 15:49:31 +0000 (UTC) X-FDA: 77429026542.21.uncle37_520d83e27297 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin21.hostedemail.com (Postfix) with ESMTP id AEBE8180442C2 for ; Fri, 30 Oct 2020 15:49:31 +0000 (UTC) X-HE-Tag: uncle37_520d83e27297 X-Filterd-Recvd-Size: 4016 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Fri, 30 Oct 2020 15:49:31 +0000 (UTC) Received: from localhost.localdomain (HSI-KBW-46-223-126-90.hsi.kabel-badenwuerttemberg.de [46.223.126.90]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ED397206E9; Fri, 30 Oct 2020 15:49:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604072969; bh=xH/xlh89YROcQ6IGanzE2IUwe7x9ABvjpXSH43dVrJE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WVmWqQwGHaS4dTDzDIyxXEX9rwVMnmELKiEcch4wuAWUu8jAMUxoLWiZkQfs4syTF F84Lc34G02PqLbS7gUO690oFismOg2pygTQWoC8GmN6c7zobjVWdHA3RXEXTJh299w R7/iMgOB2iHrCSL1nCvDdOuXub2rAYRb+K9ubr3M= From: Arnd Bergmann To: Russell King , Christoph Hellwig Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, viro@zeniv.linux.org.uk, linus.walleij@linaro.org, arnd@arndb.de Subject: [PATCH 1/9] mm/maccess: fix unaligned copy_{from,to}_kernel_nofault Date: Fri, 30 Oct 2020 16:49:11 +0100 Message-Id: <20201030154919.1246645-1-arnd@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20201030154519.1245983-1-arnd@kernel.org> References: <20201030154519.1245983-1-arnd@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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 On machines such as ARMv5 that trap unaligned accesses, these two functions can be slow when each access needs to be emulated, or they might not work at all. Change them so that each loop is only used when both the src and dst pointers are naturally aligned. Reviewed-by: Christoph Hellwig Signed-off-by: Arnd Bergmann --- mm/maccess.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) diff --git a/mm/maccess.c b/mm/maccess.c index 3bd70405f2d8..d3f1a1f0b1c1 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -24,13 +24,21 @@ bool __weak copy_from_kernel_nofault_allowed(const vo= id *unsafe_src, =20 long copy_from_kernel_nofault(void *dst, const void *src, size_t size) { + unsigned long align =3D 0; + + if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) + align =3D (unsigned long)dst | (unsigned long)src; + if (!copy_from_kernel_nofault_allowed(src, size)) return -ERANGE; =20 pagefault_disable(); - copy_from_kernel_nofault_loop(dst, src, size, u64, Efault); - copy_from_kernel_nofault_loop(dst, src, size, u32, Efault); - copy_from_kernel_nofault_loop(dst, src, size, u16, Efault); + if (!(align & 7)) + copy_from_kernel_nofault_loop(dst, src, size, u64, Efault); + if (!(align & 3)) + copy_from_kernel_nofault_loop(dst, src, size, u32, Efault); + if (!(align & 1)) + copy_from_kernel_nofault_loop(dst, src, size, u16, Efault); copy_from_kernel_nofault_loop(dst, src, size, u8, Efault); pagefault_enable(); return 0; @@ -50,10 +58,18 @@ EXPORT_SYMBOL_GPL(copy_from_kernel_nofault); =20 long copy_to_kernel_nofault(void *dst, const void *src, size_t size) { + unsigned long align =3D 0; + + if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) + align =3D (unsigned long)dst | (unsigned long)src; + pagefault_disable(); - copy_to_kernel_nofault_loop(dst, src, size, u64, Efault); - copy_to_kernel_nofault_loop(dst, src, size, u32, Efault); - copy_to_kernel_nofault_loop(dst, src, size, u16, Efault); + if (!(align & 7)) + copy_to_kernel_nofault_loop(dst, src, size, u64, Efault); + if (!(align & 3)) + copy_to_kernel_nofault_loop(dst, src, size, u32, Efault); + if (!(align & 1)) + copy_to_kernel_nofault_loop(dst, src, size, u16, Efault); copy_to_kernel_nofault_loop(dst, src, size, u8, Efault); pagefault_enable(); return 0; --=20 2.27.0