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=-14.3 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL 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 B119FC3A5A0 for ; Mon, 19 Aug 2019 15:47:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 73C1D2070B for ; Mon, 19 Aug 2019 15:47:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="hb156RXe" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 73C1D2070B Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 173366B026F; Mon, 19 Aug 2019 11:47:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0FD0A6B0270; Mon, 19 Aug 2019 11:47:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EDF866B0271; Mon, 19 Aug 2019 11:47:27 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0098.hostedemail.com [216.40.44.98]) by kanga.kvack.org (Postfix) with ESMTP id C639A6B026F for ; Mon, 19 Aug 2019 11:47:27 -0400 (EDT) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 69508181AC9AE for ; Mon, 19 Aug 2019 15:47:27 +0000 (UTC) X-FDA: 75839606934.14.food08_5e2154fd23c32 X-HE-Tag: food08_5e2154fd23c32 X-Filterd-Recvd-Size: 5644 Received: from mail-pf1-f195.google.com (mail-pf1-f195.google.com [209.85.210.195]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Mon, 19 Aug 2019 15:47:26 +0000 (UTC) Received: by mail-pf1-f195.google.com with SMTP id d85so1400393pfd.2 for ; Mon, 19 Aug 2019 08:47:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=GVKhbnPbpjWbhz5xDYatb5Jf0xezOaFTSU5iPuDRTeo=; b=hb156RXeMFMq/ZFBxV79hUwsJ33TBPwNChB7tz9IM49HqYq3bFTECBQ0jWs93GlT2G SEOQohdK8Qpvg992CDM37AZOCtspic82CV7MxeJ16y4n+GAIARuDtkAqM0Vpcs5ugO59 3sRkxC82ZNpPiJFiSjHCE8xFRcNyFvlrnKXcUERASk/OU7gh9oUuKntlcF8+9VOgRdQO XwzHDLp8GeaF9DmG79eL+xmRZIDuOI163umv7VF+AUJ3CNUJ8QSO3555UzdSqQRzm98/ M6E4uyzHKgmn+l3ROAiDQuvOoBKPpaBx3AvAN7T4WwNWZXw8eHWQZ7MH/qOuEtyRVpnD 8p+A== 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=GVKhbnPbpjWbhz5xDYatb5Jf0xezOaFTSU5iPuDRTeo=; b=byo1P3E+lRQ/vUkUqAA5g1VX3NmmGln/n4mC7I5D3L+fBQhiycnYgDc2B8p2bvpDY7 Q+yhu0yq6mpuneUQDSwi1kIvbXiOMT5QQd7qHZS3F0fLDniuOsqSg5i8MTaZHwvmH2sF 7kubEKJ1kJZNygUeC+4mwr3Vxm53c25NkgEvEupEwjJ8UIby0mf2wHcSZcVlB1T6Qz5Z H/QKOIJCzQmlfGpbaFkfdpIqpr5OdJRZKOgy++N+1VfZM99MZNeELrXUHHncG4kHYeya S+qTB6EAEq61A8+tAhZ7wIcRiVCca8DpIGgaqluFHKnyb8gkof2gqxH/H6x3L+t1etKK 6Sqg== X-Gm-Message-State: APjAAAWnqpDE+dtKCHqfrWb59xIuaemQujzSR2vChTwZowCVchuCOxkr SoJ2TDOLTwZ3wh4BuEnIK5VYgU5FSnapV63QtVFMqg== X-Google-Smtp-Source: APXvYqxLTHM5LEFPfn7KCCEc2GvHDBYCQbwS1b0CfA10FVE2b1wMY/bojyivxbvU4UFTnmGkD/DFGafc0BRQouvpbVg= X-Received: by 2002:a17:90a:858c:: with SMTP id m12mr21540803pjn.129.1566229645488; Mon, 19 Aug 2019 08:47:25 -0700 (PDT) MIME-Version: 1.0 References: <20190815154403.16473-1-catalin.marinas@arm.com> <20190815154403.16473-4-catalin.marinas@arm.com> In-Reply-To: <20190815154403.16473-4-catalin.marinas@arm.com> From: Andrey Konovalov Date: Mon, 19 Aug 2019 17:47:14 +0200 Message-ID: Subject: Re: [PATCH v8 3/5] arm64: Change the tagged_addr sysctl control semantics to only prevent the opt-in To: Catalin Marinas Cc: Linux ARM , Linux Memory Management List , Andrew Morton , Vincenzo Frascino , Will Deacon , Szabolcs Nagy , Kevin Brodsky , Dave P Martin , Dave Hansen , "open list:DOCUMENTATION" , linux-arch Content-Type: text/plain; charset="UTF-8" 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: On Thu, Aug 15, 2019 at 5:44 PM Catalin Marinas wrote: > > First rename the sysctl control to abi.tagged_addr_disabled and make it > default off (zero). When abi.tagged_addr_disabled == 1, only block the > enabling of the TBI ABI via prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE). > Getting the status of the ABI or disabling it is still allowed. > > Signed-off-by: Catalin Marinas Acked-by: Andrey Konovalov > --- > arch/arm64/kernel/process.c | 17 ++++++++++------- > 1 file changed, 10 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > index 76b7c55026aa..03689c0beb34 100644 > --- a/arch/arm64/kernel/process.c > +++ b/arch/arm64/kernel/process.c > @@ -579,17 +579,22 @@ void arch_setup_new_exec(void) > /* > * Control the relaxed ABI allowing tagged user addresses into the kernel. > */ > -static unsigned int tagged_addr_prctl_allowed = 1; > +static unsigned int tagged_addr_disabled; > > long set_tagged_addr_ctrl(unsigned long arg) > { > - if (!tagged_addr_prctl_allowed) > - return -EINVAL; > if (is_compat_task()) > return -EINVAL; > if (arg & ~PR_TAGGED_ADDR_ENABLE) > return -EINVAL; > > + /* > + * Do not allow the enabling of the tagged address ABI if globally > + * disabled via sysctl abi.tagged_addr_disabled. > + */ > + if (arg & PR_TAGGED_ADDR_ENABLE && tagged_addr_disabled) > + return -EINVAL; > + > update_thread_flag(TIF_TAGGED_ADDR, arg & PR_TAGGED_ADDR_ENABLE); > > return 0; > @@ -597,8 +602,6 @@ long set_tagged_addr_ctrl(unsigned long arg) > > long get_tagged_addr_ctrl(void) > { > - if (!tagged_addr_prctl_allowed) > - return -EINVAL; > if (is_compat_task()) > return -EINVAL; > > @@ -618,9 +621,9 @@ static int one = 1; > > static struct ctl_table tagged_addr_sysctl_table[] = { > { > - .procname = "tagged_addr", > + .procname = "tagged_addr_disabled", > .mode = 0644, > - .data = &tagged_addr_prctl_allowed, > + .data = &tagged_addr_disabled, > .maxlen = sizeof(int), > .proc_handler = proc_dointvec_minmax, > .extra1 = &zero,