From: David Miller <davem@davemloft.net>
To: ast@plumgrid.com
Cc: zlim.lnx@gmail.com, edumazet@google.com, dborkman@redhat.com,
hpa@zytor.com, tglx@linutronix.de, mingo@kernel.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 net] bpf: x86: fix epilogue generation for eBPF programs
Date: Fri, 05 Dec 2014 21:24:33 -0800 (PST) [thread overview]
Message-ID: <20141205.212433.750912400773154348.davem@davemloft.net> (raw)
In-Reply-To: <1417301173-23691-1-git-send-email-ast@plumgrid.com>
From: Alexei Starovoitov <ast@plumgrid.com>
Date: Sat, 29 Nov 2014 14:46:13 -0800
> classic BPF has a restriction that last insn is always BPF_RET.
> eBPF doesn't have BPF_RET instruction and this restriction.
> It has BPF_EXIT insn which can appear anywhere in the program
> one or more times and it doesn't have to be last insn.
> Fix eBPF JIT to emit epilogue when first BPF_EXIT is seen
> and all other BPF_EXIT instructions will be emitted as jump.
>
> Since jump offset to epilogue is computed as:
> jmp_offset = ctx->cleanup_addr - addrs[i]
> we need to change type of cleanup_addr to signed to compute the offset as:
> (long long) ((int)20 - (int)30)
> instead of:
> (long long) ((unsigned int)20 - (int)30)
>
> Fixes: 622582786c9e ("net: filter: x86: internal BPF JIT")
> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Applied, thanks.
prev parent reply other threads:[~2014-12-06 5:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-29 22:46 [PATCH v2 net] bpf: x86: fix epilogue generation for eBPF programs Alexei Starovoitov
2014-12-03 6:38 ` Z Lim
2014-12-03 15:51 ` Alexei Starovoitov
2014-12-06 5:24 ` David Miller [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20141205.212433.750912400773154348.davem@davemloft.net \
--to=davem@davemloft.net \
--cc=ast@plumgrid.com \
--cc=dborkman@redhat.com \
--cc=edumazet@google.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=zlim.lnx@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).