From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: Re: [PATCH iproute2 master] bpf: provide fallback defs for __NR_bpf when not avail Date: Thu, 15 Jun 2017 01:01:14 +0200 Message-ID: <5941C03A.6010107@iogearbox.net> References: <20170614155648.4cfd7a73@xeon-e3> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: alexei.starovoitov@gmail.com, netdev@vger.kernel.org To: Stephen Hemminger Return-path: Received: from www62.your-server.de ([213.133.104.62]:46262 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752121AbdFNXBT (ORCPT ); Wed, 14 Jun 2017 19:01:19 -0400 In-Reply-To: <20170614155648.4cfd7a73@xeon-e3> Sender: netdev-owner@vger.kernel.org List-ID: On 06/15/2017 12:56 AM, Stephen Hemminger wrote: > On Thu, 15 Jun 2017 00:47:15 +0200 > Daniel Borkmann wrote: > >> panji reported that he wasn't able to build iproute2's bpf library >> due to lack of __NR_bpf in his system headers. Providing a fallback >> definition when __NR_bpf is not available in the system lets the >> loader compile just fine, so lets add them for majority of archs. >> >> Reported-by: panji >> Signed-off-by: Daniel Borkmann >> --- >> lib/bpf.c | 20 ++++++++++++++++++++ >> 1 file changed, 20 insertions(+) >> >> diff --git a/lib/bpf.c b/lib/bpf.c >> index ae4d97d..e1e29cc 100644 >> --- a/lib/bpf.c >> +++ b/lib/bpf.c >> @@ -128,6 +128,26 @@ static inline __u64 bpf_ptr_to_u64(const void *ptr) >> return (__u64)(unsigned long)ptr; >> } >> >> +#ifndef __NR_bpf >> +# if defined(__i386__) >> +# define __NR_bpf 357 >> +# elif defined(__x86_64__) >> +# define __NR_bpf 321 >> +# elif defined(__aarch64__) >> +# define __NR_bpf 280 >> +# elif defined(__sparc__) >> +# define __NR_bpf 349 >> +# elif defined(__arm__) >> +# define __NR_bpf 386 >> +# elif defined(__powerpc__) >> +# define __NR_bpf 361 >> +# elif defined(__s390__) >> +# define __NR_bpf 351 >> +# else >> +# error __NR_bpf not defined. Update kernel headers. >> +# endif >> +#endif >> + >> static int bpf(int cmd, union bpf_attr *attr, unsigned int size) >> { >> #ifdef __NR_bpf > > Sorry this looks like a mess. enumerating architectures in two different > projects is likely to break in future. It says ifndef __NR_bpf, so only used then. And the numbers are uabi, what will break here exactly? libbpf in kernel tree is having a similar approach by the way.