bpf: btf: Fix bitfield extraction for big endian

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When extracting bitfield from a number, btf_int_bits_seq_show() builds
a mask and accesses least significant byte of the number in a way
specific to little-endian. This patch fixes that by checking endianness
of the machine and then shifting left and right the unneeded bits.

Thanks to Martin Lau for the help in navigating potential pitfalls when
dealing with endianess and for the final solution.

Fixes: b00b8daec8 ("bpf: btf: Add pretty print capability for data with BTF type info")
Signed-off-by: Okash Khawaja <osk@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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Okash Khawaja 2018-07-10 14:33:07 -07:00 • committed by Daniel Borkmann

parent 61d769807f

commit b65f370d06

1 changed files with 13 additions and 17 deletions

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kernel/bpf/btf.c

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