Messages in this thread | | | Subject | Re: [REGRESSION][PATCH V4 3/3] bpf jit: Let the powerpc jit handle negative offsets | From | Benjamin Herrenschmidt <> | Date | Mon, 30 Apr 2012 13:40:46 +1000 |
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On Mon, 2012-04-30 at 12:43 +1000, Benjamin Herrenschmidt wrote:
> 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. > > I'll mess around & try to test using Jan test case & will come back > with an updated patch.
Wow, hit that nasty along the way: The test program will not work on big endian machines because of a nasty difference between the kernel struct sock_fprog and libpcap struct bpf_program:
Kernel expects:
struct sock_fprog { /* Required for SO_ATTACH_FILTER. */ unsigned short len; /* Number of filter blocks */ struct sock_filter __user *filter; };
libpcap provides:
struct bpf_program { u_int bf_len; struct bpf_insn *bf_insns; };
Note the unsigned short vs. unsigned int there ? This totally breaks it here.
Is it expected that one can pass a struct bpf_program directly to the kernel or should it be "converted" by the library in which case it's just a bug in Jan's test program ?
Cheers, Ben.
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