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| author | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2021-10-02 06:47:56 +0530 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2021-10-05 17:07:42 -0700 |
| commit | 18f4fccbf314fdb07d276f4cd3eaf53f1825550d (patch) | |
| tree | aa75df537590490fe9cd09ec10265cc2ab1c4d3d /tools/lib/bpf/libbpf.c | |
| parent | 466b2e13971ef65cd7b621ca3044be14028b002b (diff) | |
| download | linux-18f4fccbf314fdb07d276f4cd3eaf53f1825550d.tar.bz2 | |
libbpf: Update gen_loader to emit BTF_KIND_FUNC relocations
This change updates the BPF syscall loader to relocate BTF_KIND_FUNC
relocations, with support for weak kfunc relocations. The general idea
is to move map_fds to loader map, and also use the data for storing
kfunc BTF fds. Since both reuse the fd_array parameter, they need to be
kept together.
For map_fds, we reserve MAX_USED_MAPS slots in a region, and for kfunc,
we reserve MAX_KFUNC_DESCS. This is done so that insn->off has more
chances of being <= INT16_MAX than treating data map as a sparse array
and adding fd as needed.
When the MAX_KFUNC_DESCS limit is reached, we fall back to the sparse
array model, so that as long as it does remain <= INT16_MAX, we pass an
index relative to the start of fd_array.
We store all ksyms in an array where we try to avoid calling the
bpf_btf_find_by_name_kind helper, and also reuse the BTF fd that was
already stored. This also speeds up the loading process compared to
emitting calls in all cases, in later tests.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211002011757.311265-9-memxor@gmail.com
Diffstat (limited to 'tools/lib/bpf/libbpf.c')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 092cf4bd1879..f32fa51b1e63 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -6360,12 +6360,12 @@ static int bpf_program__record_externs(struct bpf_program *prog) ext->name); return -ENOTSUP; } - bpf_gen__record_extern(obj->gen_loader, ext->name, BTF_KIND_VAR, - relo->insn_idx); + bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak, + BTF_KIND_VAR, relo->insn_idx); break; case RELO_EXTERN_FUNC: - bpf_gen__record_extern(obj->gen_loader, ext->name, BTF_KIND_FUNC, - relo->insn_idx); + bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak, + BTF_KIND_FUNC, relo->insn_idx); break; default: continue; |