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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 4C2A8C433E2 for ; Sat, 5 Sep 2020 11:25:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2BAB20760 for ; Sat, 5 Sep 2020 11:25:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="H5fhTYLn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726597AbgIELZM (ORCPT ); Sat, 5 Sep 2020 07:25:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728469AbgIELZJ (ORCPT ); Sat, 5 Sep 2020 07:25:09 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89A8BC061244; Sat, 5 Sep 2020 04:24:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=RcCo8rpDVaNpQkStt8c1HunAQwH7Y1hkDms25uGh7OM=; b=H5fhTYLnze+6FRQQl4W6tmfH1q pcIodbtZk0OZNy1KMaQTx5BS8S0CDbBZcr/8epL6/qMDSFzs52nOdoO8lVQW9tofPDZJDQx8A+nQZ SP5WBd5Lt7+WFiHjRZ5U5NeD1JdUH8LYQ7LRVitgJBSLXj3PIdezDLjvbFnFEAf/LB+tlBvhjd/P6 8W+BoR9OzLU7bO4kjLDP5F483ZezNZPg/YwE/lreGRBFF+PmZJ4NbBZyU+iC9qBiUciNFrmN7V7/I 1ls9g2doQTwnJH+JRPyGSZbHF2VKf89ceWGTMDjCGVhY0amiyxJlqK06cFWWIHxhPnmnb1G91GUwD AZ2H91Gw==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kEWJC-0006qo-6M; Sat, 05 Sep 2020 11:24:38 +0000 Date: Sat, 5 Sep 2020 12:24:38 +0100 From: Matthew Wilcox To: Gabriel Krisman Bertazi Cc: luto@kernel.org, tglx@linutronix.de, keescook@chromium.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-kselftest@vger.kernel.org, shuah@kernel.org, kernel@collabora.com, Paul Gofman Subject: Re: [PATCH v6 5/9] kernel: Implement selective syscall userspace redirection Message-ID: <20200905112438.GA16750@casper.infradead.org> References: <20200904203147.2908430-1-krisman@collabora.com> <20200904203147.2908430-6-krisman@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200904203147.2908430-6-krisman@collabora.com> Sender: linux-api-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Fri, Sep 04, 2020 at 04:31:43PM -0400, Gabriel Krisman Bertazi wrote: > +int set_syscall_user_dispatch(int mode, unsigned long dispatcher_start, > + unsigned long dispatcher_end, char __user *selector) > +{ > + switch (mode) { > + case PR_SYS_DISPATCH_OFF: ... > + case PR_SYS_DISPATCH_ON: ... > + default: > + return -EINVAL; ... > + case PR_SET_SYSCALL_USER_DISPATCH: > + error = set_syscall_user_dispatch((int) arg2, arg3, arg4, > + (char __user *) arg5); This makes aliases of DISPATCH_OFF and DISPATCH_ON every 4GB throughout the 64-bit space of arg2. I don't think that was intentional (nor desirable). I'd suggest just making 'mode' a long and dropping the cast.