bpf: Recognize btf_decl_tag("arg: Arena") as PTR_TO_ARENA.

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In global bpf functions recognize btf_decl_tag("arg:arena") as PTR_TO_ARENA.

Note, when the verifier sees:

__weak void foo(struct bar *p)

it recognizes 'p' as PTR_TO_MEM and 'struct bar' has to be a struct with scalars.
Hence the only way to use arena pointers in global functions is to tag them with "arg:arena".

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20240308010812.89848-7-alexei.starovoitov@gmail.com

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Alexei Starovoitov 2024-03-07 17:08:04 -08:00 • committed by Andrii Nakryiko

parent 6082b6c328

commit 2edc3de6fb

3 changed files with 31 additions and 4 deletions

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1

include/linux/bpf.h

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19

kernel/bpf/btf.c

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15

kernel/bpf/verifier.c

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