x86: bpf_jit: support negative offsets
authorAlexei Starovoitov <ast@plumgrid.com>
Mon, 10 Mar 2014 22:56:51 +0000 (15:56 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 31 Mar 2014 16:58:13 +0000 (09:58 -0700)
commit32f139873e89672cbd5b28f5da944201e86fdb92
tree82d7b1abeefc6a6b141e25e3361d4f7bed49650a
parent21680f38b5994c8d839380e7cf002496a51962a2
x86: bpf_jit: support negative offsets

commit fdfaf64e75397567257e1051931f9a3377360665 upstream.

Commit a998d4342337 claimed to introduce negative offset support to x86 jit,
but it couldn't be working, since at the time of the execution
of LD+ABS or LD+IND instructions via call into
bpf_internal_load_pointer_neg_helper() the %edx (3rd argument of this func)
had junk value instead of access size in bytes (1 or 2 or 4).

Store size into %edx instead of %ecx (what original commit intended to do)

Fixes: a998d4342337 ("bpf jit: Let the x86 jit handle negative offsets")
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Jan Seiffert <kaffeemonster@googlemail.com>
Cc: Eric Dumazet <edumazet@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/net/bpf_jit.S