From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH v3 binutils] Add BPF support to binutils... Date: Sun, 30 Apr 2017 11:40:24 -0400 (EDT) Message-ID: <20170430.114024.1304052185817716163.davem@davemloft.net> References: <20170429.222450.1300920007783667009.davem@davemloft.net> <20170429.223759.1262491011130998405.davem@davemloft.net> <76ed19a7-add3-0642-4298-9402c7ff0be8@fb.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: daniel@iogearbox.net, aconole@bytheb.org, netdev@vger.kernel.org, xdp-newbies@vger.kernel.org To: ast@fb.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:49852 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751211AbdD3Pk0 (ORCPT ); Sun, 30 Apr 2017 11:40:26 -0400 In-Reply-To: <76ed19a7-add3-0642-4298-9402c7ff0be8@fb.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Alexei Starovoitov Date: Sat, 29 Apr 2017 23:44:59 -0700 > On 4/29/17 7:37 PM, David Miller wrote: >> BTW, should I just remove tailcall from the opcode table altogether? > > yeah. tailcall is not a special opcode from user space point of view. > Only after normal call with func_id=bpf_tail_call passes verifier > then verifier will change insn->code into CALL|X > It's done only to have two 'case' statement in the interpreter, > so that normal calls and tailcalls don't interfere. > From user space pov CALL|X opcode is reserved and we can use it > for something in the future. Just need to change interpeter and JITs. Ok, I've removed it from my tree. Thanks.