From 32f139873e89672cbd5b28f5da944201e86fdb92 Mon Sep 17 00:00:00 2001
From: Alexei Starovoitov <ast@plumgrid.com>
Date: Mon, 10 Mar 2014 15:56:51 -0700
Subject: 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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'arch')

diff --git a/arch/x86/net/bpf_jit.S b/arch/x86/net/bpf_jit.S
index 877b9a1b215..01495755701 100644
--- a/arch/x86/net/bpf_jit.S
+++ b/arch/x86/net/bpf_jit.S
@@ -140,7 +140,7 @@ bpf_slow_path_byte_msh:
 	push	%r9;						\
 	push	SKBDATA;					\
 /* rsi already has offset */					\
-	mov	$SIZE,%ecx;	/* size */			\
+	mov	$SIZE,%edx;	/* size */			\
 	call	bpf_internal_load_pointer_neg_helper;		\
 	test	%rax,%rax;					\
 	pop	SKBDATA;					\
-- 
cgit v1.2.3-18-g5258