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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,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 79D10C04EB9 for ; Wed, 5 Dec 2018 15:41:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A58F206B7 for ; Wed, 5 Dec 2018 15:41:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4A58F206B7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=iogearbox.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728314AbeLEPlJ (ORCPT ); Wed, 5 Dec 2018 10:41:09 -0500 Received: from www62.your-server.de ([213.133.104.62]:54938 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728239AbeLEPk6 (ORCPT ); Wed, 5 Dec 2018 10:40:58 -0500 Received: from [78.46.172.3] (helo=sslproxy06.your-server.de) by www62.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89_1) (envelope-from ) id 1gUZIB-0003bb-Qs; Wed, 05 Dec 2018 16:40:51 +0100 Received: from [2a02:1203:ecb1:b710:c81f:d2d6:50a9:c2d] (helo=linux.home) by sslproxy06.your-server.de with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1gUZIB-000J5Z-Kg; Wed, 05 Dec 2018 16:40:51 +0100 Subject: Re: [PATCH v4 2/2] arm64/bpf: don't allocate BPF JIT programs in module memory To: Will Deacon Cc: Ard Biesheuvel , Linux Kernel Mailing List , Alexei Starovoitov , Rick Edgecombe , Eric Dumazet , Jann Horn , Kees Cook , Jessica Yu , Arnd Bergmann , Catalin Marinas , Mark Rutland , "David S. Miller" , linux-arm-kernel , "" References: <20181123221804.440-1-ard.biesheuvel@linaro.org> <20181123221804.440-3-ard.biesheuvel@linaro.org> <20181130182629.GA16085@arm.com> <20181203124930.GB25097@arm.com> <12954298-de06-349e-6df2-c218e5bf09a3@iogearbox.net> <20181205132444.GA15631@arm.com> From: Daniel Borkmann Message-ID: Date: Wed, 5 Dec 2018 16:40:50 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <20181205132444.GA15631@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.100.2/25179/Tue Dec 4 15:18:37 2018) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/05/2018 02:24 PM, Will Deacon wrote: > On Wed, Dec 05, 2018 at 01:24:17PM +0100, Daniel Borkmann wrote: >> On 12/04/2018 04:45 PM, Ard Biesheuvel wrote: >>> On Mon, 3 Dec 2018 at 13:49, Will Deacon wrote: >>>> On Fri, Nov 30, 2018 at 08:20:06PM +0100, Ard Biesheuvel wrote: >>>>> On Fri, 30 Nov 2018 at 19:26, Will Deacon wrote: >>>>>> On Fri, Nov 23, 2018 at 11:18:04PM +0100, Ard Biesheuvel wrote: >>>>>>> diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c >>>>>>> index a6fdaea07c63..76c2ab40c02d 100644 >>>>>>> --- a/arch/arm64/net/bpf_jit_comp.c >>>>>>> +++ b/arch/arm64/net/bpf_jit_comp.c >>>>>>> @@ -940,3 +940,16 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) >>>>>>> tmp : orig_prog); >>>>>>> return prog; >>>>>>> } >>>>>>> + >>>>>>> +void *bpf_jit_alloc_exec(unsigned long size) >>>>>>> +{ >>>>>>> + return __vmalloc_node_range(size, PAGE_SIZE, BPF_JIT_REGION_START, >>>>>>> + BPF_JIT_REGION_END, GFP_KERNEL, >>>>>>> + PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, >>>>>>> + __builtin_return_address(0)); >>>>>> >>>>>> I guess we'll want VM_IMMEDIATE_UNMAP here if Rich gets that merged. >>>>> >>>>> I think akpm already queued up that patch. >>>>> >>>>>> In the >>>>>> meantime, I wonder if it's worth zeroing the region in bpf_jit_free_exec()? >>>>>> (although we'd need the size information...). >>>>>> >>>>> >>>>> Not sure. What exactly would that achieve? >>>> >>>> I think the zero encoding is guaranteed to be undefined, so it would limit >>>> the usefulness of any stale, executable TLB entries. However, we'd also need >>>> cache maintenance to make that stuff visible to the I side, so it's probably >>>> not worth it, especially if akpm has queued the stuff from Rich. >>>> >>>> Maybe just add an: >>>> >>>> /* FIXME: Remove this when VM_IMMEDIATE_UNMAP is supported */ >>>> #ifndef VM_IMMEDIATE_UNMAP >>>> #define VM_IMMEDIATE_UNMAP 0 >>>> #endif >>>> >>>> so we remember to come back and sort this out? Up to you. >>> >>> I'll just make a note to send out that patch once the definition lands via -akpm >> >> Could I get an ACK from you for this patch, then I'd take the series into bpf-next. > > Gah, thanks for the ping: I thought I acked this initially, but turns out I > didn't. > > Acked-by: Will Deacon Applied, thanks everyone!