From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: Re: [PATCH net-next 1/9] bpf: add BPF_J{LT,LE,SLT,SLE} instructions Date: Wed, 09 Aug 2017 19:03:03 +0200 Message-ID: <598B4047.2090701@iogearbox.net> References: <63b41a38e0d58536700c999ade7c2c267bd2613d.1502272924.git.daniel@iogearbox.net> <20170809.095553.268665355274669790.davem@davemloft.net> <598B3FCA.7060904@iogearbox.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: ast@fb.com, holzheu@linux.vnet.ibm.com, naveen.n.rao@linux.vnet.ibm.com, jakub.kicinski@netronome.com, netdev@vger.kernel.org To: David Miller Return-path: Received: from www62.your-server.de ([213.133.104.62]:37699 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754232AbdHIRDI (ORCPT ); Wed, 9 Aug 2017 13:03:08 -0400 In-Reply-To: <598B3FCA.7060904@iogearbox.net> Sender: netdev-owner@vger.kernel.org List-ID: On 08/09/2017 07:00 PM, Daniel Borkmann wrote: > On 08/09/2017 06:55 PM, David Miller wrote: >> From: Daniel Borkmann >> Date: Wed, 9 Aug 2017 12:23:53 +0200 >> >>> [1] https://github.com/borkmann/llvm/tree/bpf-insns >> >> How is this "backwards compatible"? >> >> If someone takes a new LLVM and tries to load those programs >> into an older kernel they will be rejected. >> >> There appears to be no effort to make things work cleanly in >> that situation at all. > > No, that was just the patch I used for LLVM to enable the > insns, so not the final one that will be submitted there > officially where we have a switch to enable/disable this > functionality. (In other words the one I used for doing the measurements.)