bpf: Handle sign-extenstin ctx member accesses

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Currently, if user accesses a ctx member with signed types,
the compiler will generate an unsigned load followed by
necessary left and right shifts.

With the introduction of sign-extension load, compiler may
just emit a ldsx insn instead. Let us do a final movsx sign
extension to the final unsigned ctx load result to
satisfy original sign extension requirement.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011207.3712528-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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Yonghong Song 2023-07-27 18:12:07 -07:00 • committed by Alexei Starovoitov

parent 8100928c88

commit 1f1e864b65

1 changed files with 6 additions and 0 deletions

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kernel/bpf/verifier.c

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