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authorDaniel Borkmann <daniel@iogearbox.net>2019-04-10 00:20:10 +0300
committerAlexei Starovoitov <ast@kernel.org>2019-04-10 03:05:46 +0300
commit2824ecb7010f6a20e9a4140512b798469ab066cc (patch)
treebb72402c12f3dd2f34be1d12e460442e7ed79b54 /include
parent1dc92851849cc2235a1efef8f8d5a9255efc5f13 (diff)
downloadlinux-2824ecb7010f6a20e9a4140512b798469ab066cc.tar.xz
bpf: allow for key-less BTF in array map
Given we'll be reusing BPF array maps for global data/bss/rodata sections, we need a way to associate BTF DataSec type as its map value type. In usual cases we have this ugly BPF_ANNOTATE_KV_PAIR() macro hack e.g. via 38d5d3b3d5db ("bpf: Introduce BPF_ANNOTATE_KV_PAIR") to get initial map to type association going. While more use cases for it are discouraged, this also won't work for global data since the use of array map is a BPF loader detail and therefore unknown at compilation time. For array maps with just a single entry we make an exception in terms of BTF in that key type is declared optional if value type is of DataSec type. The latter LLVM is guaranteed to emit and it also aligns with how we regard global data maps as just a plain buffer area reusing existing map facilities for allowing things like introspection with existing tools. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/btf.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/btf.h b/include/linux/btf.h
index 455d31b55828..64cdf2a23d42 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -51,6 +51,7 @@ bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
const struct btf_member *m,
u32 expected_offset, u32 expected_size);
int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t);
+bool btf_type_is_void(const struct btf_type *t);
#ifdef CONFIG_BPF_SYSCALL
const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);