Commit 5cbd3fe3 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Andrii Nakryiko
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libbpf: Introduce bpf_ksym_exists() macro. 



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: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230317201920.62030-4-alexei.starovoitov@gmail.com
parent 5fc13ad5

tools/lib/bpf/bpf_helpers.h

+5 −0
Original line number Diff line number Diff line
@@ -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