From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>
Subject: Re: [PATCH RFC v4 net-next 17/26] tracing: allow eBPF programs to be
 attached to events
Date: Fri, 15 Aug 2014 11:50:49 -0700
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Cc: Daniel Borkmann <dborkman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
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	Linux API <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Chema Gonzalez <chema-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
	Eric Dumazet <edumazet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
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	Brendan Gregg <brendan.d.gregg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
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	LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Peter Zijlstra <a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>,
	Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
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	Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Alexei Starovoitov <ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
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On Aug 15, 2014 10:36 AM, "Alexei Starovoitov" <ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org> wrote:
>
> On Fri, Aug 15, 2014 at 10:20 AM, Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org> wrote:
> > The downside of this approach is that compat support might be
> > difficult or impossible.
>
> Would do you mean by compat? 32-bit programs on 64-bit kernels?
> There is no such concept for eBPF. All eBPF programs are always
> operating on 64-bit registers.

Doesn't the eBPF program need to know sizeof(long) to read these
fields correctly?  Or am I misunderstanding what the code does?

--Andy