bpf: allow b/h/w/dw access for bpf's cb in ctx

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When structs are used to store temporary state in cb[] buffer that is
used with programs and among tail calls, then the generated code will
not always access the buffer in bpf_w chunks. We can ease programming
of it and let this act more natural by allowing for aligned b/h/w/dw
sized access for cb[] ctx member. Various test cases are attached as
well for the selftest suite. Potentially, this can also be reused for
other program types to pass data around.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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Daniel Borkmann 2017-01-12 11:51:33 +01:00 • committed by David S. Miller

parent 6b8cc1d11e

commit 62c7989b24

3 changed files with 478 additions and 13 deletions

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8

kernel/bpf/verifier.c

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41

net/core/filter.c

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442

tools/testing/selftests/bpf/test_verifier.c

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