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=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 A76ACC35243 for ; Fri, 24 Jan 2020 11:54:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6E382206F0 for ; Fri, 24 Jan 2020 11:54:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="bwZsiipU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6E382206F0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1A4196B000A; Fri, 24 Jan 2020 06:54:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1532C6B000C; Fri, 24 Jan 2020 06:54:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 08F146B000D; Fri, 24 Jan 2020 06:54:44 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0241.hostedemail.com [216.40.44.241]) by kanga.kvack.org (Postfix) with ESMTP id E0DF26B000A for ; Fri, 24 Jan 2020 06:54:44 -0500 (EST) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 8B243824556B for ; Fri, 24 Jan 2020 11:54:44 +0000 (UTC) X-FDA: 76412370888.14.owner77_80a7f2671431c X-HE-Tag: owner77_80a7f2671431c X-Filterd-Recvd-Size: 4789 Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) by imf14.hostedemail.com (Postfix) with ESMTP for ; Fri, 24 Jan 2020 11:54:43 +0000 (UTC) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 483yHP4WVnz9tyN8; Fri, 24 Jan 2020 12:54:41 +0100 (CET) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=bwZsiipU; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id SSrNdcuyBBuq; Fri, 24 Jan 2020 12:54:41 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 483yHP3MZ0z9tyMv; Fri, 24 Jan 2020 12:54:41 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1579866881; bh=VLx+Lz40VzpGWWhkdYBRnnJLZiSw4fD8aXzdGmSoxMc=; h=In-Reply-To:References:From:Subject:To:Cc:Date:From; b=bwZsiipUE7XPgOvT/fv2tqC+/BWEPK6x8YER7CmIw+j4b5yIyqSryoZtfG0J7w+Tf ZzZL2Q/9A94nVbWguyBkIyRGVFggtzAk1vSu8pZ2wXAHAKGyNcdqOVhqKB0aIWTh5a QQOzfPsEfaQ1xj33F6c7Av5mksgYB3EtZPDKDfIE= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 9A1C98B85C; Fri, 24 Jan 2020 12:54:42 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id rOBxj6ZDwIhG; Fri, 24 Jan 2020 12:54:42 +0100 (CET) Received: from po14934vm.idsi0.si.c-s.fr (po15451.idsi0.si.c-s.fr [172.25.230.111]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 80CE08B84A; Fri, 24 Jan 2020 12:54:42 +0100 (CET) Received: by po14934vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 62D06651F0; Fri, 24 Jan 2020 11:54:42 +0000 (UTC) Message-Id: <85e971223dfe6ace734637db1841678939a76155.1579866752.git.christophe.leroy@c-s.fr> In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v4 4/7] powerpc/32s: Drop NULL addr verification To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org Date: Fri, 24 Jan 2020 11:54:42 +0000 (UTC) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: NULL addr is a user address. Don't waste time checking it. If someone tries to access it, it will SIGFAULT the same way as for address 1, so no need to make it special. The special case is when not doing a write, in that case we want to drop the entire function. This is now handled by 'dir' param and not by the nulity of 'to' anymore. Also make beginning of prevent_user_access() similar to beginning of allow_user_access(), and tell the compiler that writing in kernel space or with a 0 length is unlikely Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/d79cb9f680f4e971e05262303103a4b94baa91ce.1579715466.git.christophe.leroy@c-s.fr --- v4: taken from powerpc/merge-test --- arch/powerpc/include/asm/book3s/32/kup.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h index 91c8f1d9bcee..de29fb752cca 100644 --- a/arch/powerpc/include/asm/book3s/32/kup.h +++ b/arch/powerpc/include/asm/book3s/32/kup.h @@ -113,7 +113,7 @@ static __always_inline void allow_user_access(void __user *to, const void __user addr = (__force u32)to; - if (!addr || addr >= TASK_SIZE || !size) + if (unlikely(addr >= TASK_SIZE || !size)) return; end = min(addr + size, TASK_SIZE); @@ -124,16 +124,18 @@ static __always_inline void allow_user_access(void __user *to, const void __user static __always_inline void prevent_user_access(void __user *to, const void __user *from, u32 size, unsigned long dir) { - u32 addr = (__force u32)to; - u32 end = min(addr + size, TASK_SIZE); + u32 addr, end; BUILD_BUG_ON(!__builtin_constant_p(dir)); if (!(dir & KUAP_WRITE)) return; - if (!addr || addr >= TASK_SIZE || !size) + addr = (__force u32)to; + + if (unlikely(addr >= TASK_SIZE || !size)) return; + end = min(addr + size, TASK_SIZE); current->thread.kuap = 0; kuap_update_sr(mfsrin(addr) | SR_KS, addr, end); /* set Ks */ } -- 2.25.0