Re: [PATCH] MIPS: Add missing file for eBPF JIT.

From: Daniel Borkmann
Date: Fri Aug 04 2017 - 09:05:30 EST


On 08/04/2017 02:10 AM, David Daney wrote:
Inexplicably, commit f381bf6d82f0 ("MIPS: Add support for eBPF JIT.")
lost a file somewhere on its path to Linus' tree. Add back the
missing ebpf_jit.c so that we can build with CONFIG_BPF_JIT selected.

This version of ebpf_jit.c is identical to the original except for two
minor change need to resolve conflicts with changes merged from the
BPF branch:

A) Set prog->jited_len = image_size;
B) Use BPF_TAIL_CALL instead of BPF_CALL | BPF_X

Fixes: f381bf6d82f0 ("MIPS: Add support for eBPF JIT.")
Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
---

It might be best to merge this along the path of BPF fixes rather than
MIPS, as the MIPS maintainer (Ralf) seems to be inactive recently.

Looks like situation is that multiple people including myself tried
to contact Ralf due to 'half/mis-applied' MIPS BPF JIT in [1,2] that
sits currently in Linus tree, but never got a reply back since mid June.

Given the work was accepted long ago but incorrectly merged, would be
great if this could still be fixed up with this patch. Given Ralf seems
unfortunately unresponsive, is there a chance, if people are fine with
it, that we could try route this fix e.g. via -net instead before a
final v4.13?

Anyway, the generic pieces interacting with core BPF look good to me:

Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>

Thanks,
Daniel

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f381bf6d82f032b7410185b35d000ea370ac706b
[2] https://patchwork.linux-mips.org/patch/16369/