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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 B896DC10F13 for ; Tue, 16 Apr 2019 09:14:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9043120675 for ; Tue, 16 Apr 2019 09:14:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728913AbfDPJOy (ORCPT ); Tue, 16 Apr 2019 05:14:54 -0400 Received: from mail-qt1-f194.google.com ([209.85.160.194]:43167 "EHLO mail-qt1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726160AbfDPJOx (ORCPT ); Tue, 16 Apr 2019 05:14:53 -0400 Received: by mail-qt1-f194.google.com with SMTP id v32so22410671qtc.10 for ; Tue, 16 Apr 2019 02:14:53 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=vi8vuKV7FF8LFTD9Ed1q0g3vJ+6TdGMNWOak7k27ocw=; b=UO9SMGCYcZON5XfHQrhuCCmBRHROfS6/rVD3+zSUmjiH5WKM6IT7OdYpara7e31XIQ gA2JgUUhsFLOKQIIPWfVQ42C3VXwbiWH1uKBXzmHikYZERNOOl8jNJaPvUE/53qW6iBs cJX2rwJsBVQijfXDWJgEueshtLVVLWfxzofs6Rk8trpgApIyPcf6rjPvn70XO4uk+R/K 8sYz+RKLhdOD+s2F6AjLt86s2yzq1Whd5H0mRg87BsIwKv+bFp237YIejaJPiILCJct9 wNFh9O2ZBDr0+ArQr9hHyDCsrqkrkNc+hzECKcolCN2oWrLMTlLRiITswbui+qDBaZ8h HqqA== X-Gm-Message-State: APjAAAVkjfswSytssnoqKj/TevPbzAcWR60gQiJt8/ACJ3P3UNJAuvmk 7EYcNhskIFaTobXFVpPhDutmLu3IxRaMD++LR18= X-Google-Smtp-Source: APXvYqxBgx0waGInw/ldbLgtjJ6hQ+aCQTBhF5b2AEyGf3wzgfednKCZAjxE18Nwx9qmdfNUADRi4CA6wrnArVoO+hY= X-Received: by 2002:a0c:93f2:: with SMTP id g47mr62680310qvg.22.1555406092667; Tue, 16 Apr 2019 02:14:52 -0700 (PDT) MIME-Version: 1.0 References: <20190416172937.6a7621f7@canb.auug.org.au> <20190416185327.5c129073@canb.auug.org.au> In-Reply-To: <20190416185327.5c129073@canb.auug.org.au> From: Arnd Bergmann Date: Tue, 16 Apr 2019 11:14:36 +0200 Message-ID: Subject: Re: [PATCH] kernel/compat.c: mark expected switch fall-throughs To: Stephen Rothwell Cc: Linux Kernel Mailing List , Deepa Dinamani , "Gustavo A. R. Silva" , Kees Cook , Jann Horn Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 16, 2019 at 10:54 AM Stephen Rothwell wrote: > On Tue, 16 Apr 2019 10:32:55 +0200 Arnd Bergmann wrote: > > We could also consider just getting rid of put_compat_sigset() and > > get_compat_sigset() but replacing them with a combined > > put_sigset()/get_sigset() that does the right thing for both native > > and compat tasks. This lets us kill a couple of compat system > > calls that only differ in their sigset_t argument. On little-endian > > systems (which are the vast majority of the installed base), there > > is no difference anyway there is no overhead anyway since > > native and compat sigset_t are identical. > > That sounds like a bigger patch that would require some real testing :-) Yes, definitely. I mainly mentioned it in case someone wants to do that work anyway, as it would avoid the need for your patch. Arnd