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Code Issues Releases Wiki Activity

libbpf: Introduce bpf_ksym_exists() macro.

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Introduce bpf_ksym_exists() macro that can be used by BPF programs
to detect at load time whether particular ksym (either variable or kfunc)
is present in the kernel.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230317201920.62030-4-alexei.starovoitov@gmail.com
This commit is contained in:
Alexei Starovoitov 2023-03-17 13:19:19 -07:00 committed by Andrii Nakryiko
parent 5fc13ad59b
commit 5cbd3fe3a9
1 changed files with 5 additions and 0 deletions
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5
tools/lib/bpf/bpf_helpers.h
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@ -177,6 +177,11 @@ enum libbpf_tristate {
#define __kptr_untrusted __attribute__((btf_type_tag("kptr_untrusted")))
#define __kptr __attribute__((btf_type_tag("kptr")))
#define bpf_ksym_exists(sym) ({ \
_Static_assert(!__builtin_constant_p(!!sym), #sym " should be marked as __weak"); \
!!sym; \
})
#ifndef ___bpf_concat
#define ___bpf_concat(a, b) a ## b
#endif