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| author | Andrii Nakryiko <andrii@kernel.org> | 2021-04-23 11:13:34 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2021-04-23 14:05:26 -0700 |
| commit | aea28a602fa19fb4fe66374030ab7e2c8ddf643e (patch) | |
| tree | 044aaf22b476bf1e16840f21a1a34eb996eed748 /tools/lib/bpf/bpf_helpers.h | |
| parent | 0fec7a3cee1cf8e4f86ff563d229408ccbdc2d66 (diff) | |
| download | linux-aea28a602fa19fb4fe66374030ab7e2c8ddf643e.tar.bz2 | |
libbpf: Mark BPF subprogs with hidden visibility as static for BPF verifier
Define __hidden helper macro in bpf_helpers.h, which is a short-hand for
__attribute__((visibility("hidden"))). Add libbpf support to mark BPF
subprograms marked with __hidden as static in BTF information to enforce BPF
verifier's static function validation algorithm, which takes more information
(caller's context) into account during a subprogram validation.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210423181348.1801389-5-andrii@kernel.org
Diffstat (limited to 'tools/lib/bpf/bpf_helpers.h')
| -rw-r--r-- | tools/lib/bpf/bpf_helpers.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index 75c7581b304c..9720dc0b4605 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -47,6 +47,14 @@ #define __weak __attribute__((weak)) #endif +/* + * Use __hidden attribute to mark a non-static BPF subprogram effectively + * static for BPF verifier's verification algorithm purposes, allowing more + * extensive and permissive BPF verification process, taking into account + * subprogram's caller context. + */ +#define __hidden __attribute__((visibility("hidden"))) + /* When utilizing vmlinux.h with BPF CO-RE, user BPF programs can't include * any system-level headers (such as stddef.h, linux/version.h, etc), and * commonly-used macros like NULL and KERNEL_VERSION aren't available through |