bpf: Add a kfunc to type cast from bpf uapi ctx to kernel ctx

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Implement bpf_cast_to_kern_ctx() kfunc which does a type cast
of a uapi ctx object to the corresponding kernel ctx. Previously
if users want to access some data available in kctx but not
in uapi ctx, bpf_probe_read_kernel() helper is needed.
The introduction of bpf_cast_to_kern_ctx() allows direct
memory access which makes code simpler and easier to understand.

Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221120195432.3113982-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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Yonghong Song 2022-11-20 11:54:32 -08:00 • committed by Alexei Starovoitov

parent cfe1456440

commit fd264ca020

4 changed files with 53 additions and 0 deletions

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5

include/linux/btf.h

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20

kernel/bpf/btf.c

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6

kernel/bpf/helpers.c

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22

kernel/bpf/verifier.c

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