From: Johannes Berg <johannes@sipsolutions•net>
To: Alexei Starovoitov <alexei.starovoitov@gmail•com>
Cc: Daniel Borkmann <daniel@iogearbox•net>,
"netdev@vger•kernel.org" <netdev@vger•kernel.org>,
Alexei Starovoitov <ast@kernel•org>
Subject: Re: eBPF - little-endian load instructions?
Date: Sat, 15 Apr 2017 09:06:11 +0200 [thread overview]
Message-ID: <1492239971.4735.5.camel@sipsolutions.net> (raw)
In-Reply-To: <20170414184228.GA41922@ast-mbp.thefacebook.com> (sfid-20170414_204234_987955_362A9588)
On Fri, 2017-04-14 at 11:42 -0700, Alexei Starovoitov wrote:
> bpf takes endianness of the cpu it runs on.
Ok, so then things are actually not as difficult as I thought.
> if we said that bpf 32-bit load insn is little endian, it would have
> screwed up all big-endian archs and the other way around.
Right.
But then basically we do only need to have builtins for endian
conversion, and #define them appropriately, as done anywhere else.
Perhaps we want to eventually be able to take advantage of "other-
endian" loads the CPU may have through the JIT, but getting it correct
first would be good :)
Either way though, it could be done with something like inline
assembly.
johannes
prev parent reply other threads:[~2017-04-15 7:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-11 10:38 eBPF - little-endian load instructions? Johannes Berg
2017-04-11 11:06 ` Daniel Borkmann
2017-04-11 11:15 ` Johannes Berg
2017-04-11 11:22 ` Daniel Borkmann
2017-04-11 11:26 ` Johannes Berg
2017-04-12 13:02 ` Johannes Berg
2017-04-12 16:58 ` Alexei Starovoitov
2017-04-12 19:38 ` Johannes Berg
2017-04-13 3:08 ` Alexei Starovoitov
2017-04-13 5:58 ` Johannes Berg
2017-04-14 18:42 ` Alexei Starovoitov
2017-04-15 7:06 ` Johannes Berg [this message]
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