Subject: Re: [REGRESSION][PATCH V4 3/3] bpf jit: Let the powerpc jit handle negative offsets

From: Benjamin Herrenschmidt <[email-masked]>
Date: Mon, 30 Apr 2012 14:11:28 +1000

On Mon, 2012-04-30 at 12:43 +1000, Benjamin Herrenschmidt wrote:

> > Matt's having a look at powerpc
> 
> Ok, he hasn't so I'll dig a bit.
> 
> No obvious wrongness (but I'm not very familiar with bpf), though I do
> have a comment: sk_negative_common() and bpf_slow_path_common() should
> be made one and single macro which takes the fallback function as an
> argument.

Ok, with the compile fix below it seems to work for me:

(Feel free to fold that into the original patch)

diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h
index af1ab5e..5c3cf2d 100644
--- a/arch/powerpc/net/bpf_jit.h
+++ b/arch/powerpc/net/bpf_jit.h
@@ -48,7 +48,13 @@
 /*
  * Assembly helpers from arch/powerpc/net/bpf_jit.S:
  */
-extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
+#define DECLARE_LOAD_FUNC(func)	\
+	extern u8 func[], func##_negative_offset[], func##_positive_offset[]
+
+DECLARE_LOAD_FUNC(sk_load_word);
+DECLARE_LOAD_FUNC(sk_load_half);
+DECLARE_LOAD_FUNC(sk_load_byte);
+DECLARE_LOAD_FUNC(sk_load_byte_msh);
 
 #define FUNCTION_DESCR_SIZE	24
 
Cheers,
Ben.