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1713d68b3b
This adds libbpf support for BTF Var and DataSec kinds. Main point here is that libbpf needs to do some preparatory work before the whole BTF object can be loaded into the kernel, that is, fixing up of DataSec size taken from the ELF section size and non-static variable offset which needs to be taken from the ELF's string section. Upstream LLVM doesn't fix these up since at time of BTF emission it is too early in the compilation process thus this information isn't available yet, hence loader needs to take care of it. Note, deduplication handling has not been in the scope of this work and needs to be addressed in a future commit. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://reviews.llvm.org/D59441 Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
108 lines
3.5 KiB
C
108 lines
3.5 KiB
C
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
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/* Copyright (c) 2018 Facebook */
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#ifndef __LIBBPF_BTF_H
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#define __LIBBPF_BTF_H
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#include <linux/types.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifndef LIBBPF_API
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#define LIBBPF_API __attribute__((visibility("default")))
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#endif
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#define BTF_ELF_SEC ".BTF"
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#define BTF_EXT_ELF_SEC ".BTF.ext"
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struct btf;
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struct btf_ext;
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struct btf_type;
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struct bpf_object;
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/*
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* The .BTF.ext ELF section layout defined as
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* struct btf_ext_header
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* func_info subsection
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*
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* The func_info subsection layout:
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* record size for struct bpf_func_info in the func_info subsection
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* struct btf_sec_func_info for section #1
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* a list of bpf_func_info records for section #1
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* where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
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* but may not be identical
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* struct btf_sec_func_info for section #2
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* a list of bpf_func_info records for section #2
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* ......
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*
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* Note that the bpf_func_info record size in .BTF.ext may not
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* be the same as the one defined in include/uapi/linux/bpf.h.
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* The loader should ensure that record_size meets minimum
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* requirement and pass the record as is to the kernel. The
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* kernel will handle the func_info properly based on its contents.
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*/
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struct btf_ext_header {
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__u16 magic;
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__u8 version;
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__u8 flags;
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__u32 hdr_len;
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/* All offsets are in bytes relative to the end of this header */
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__u32 func_info_off;
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__u32 func_info_len;
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__u32 line_info_off;
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__u32 line_info_len;
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};
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LIBBPF_API void btf__free(struct btf *btf);
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LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size);
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LIBBPF_API int btf__finalize_data(struct bpf_object *obj, struct btf *btf);
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LIBBPF_API int btf__load(struct btf *btf);
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LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
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const char *type_name);
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LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf);
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LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
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__u32 id);
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LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
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LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
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LIBBPF_API int btf__fd(const struct btf *btf);
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LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size);
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LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
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LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf);
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LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
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__u32 expected_key_size,
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__u32 expected_value_size,
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__u32 *key_type_id, __u32 *value_type_id);
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LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size);
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LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
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LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext,
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__u32 *size);
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LIBBPF_API int btf_ext__reloc_func_info(const struct btf *btf,
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const struct btf_ext *btf_ext,
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const char *sec_name, __u32 insns_cnt,
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void **func_info, __u32 *cnt);
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LIBBPF_API int btf_ext__reloc_line_info(const struct btf *btf,
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const struct btf_ext *btf_ext,
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const char *sec_name, __u32 insns_cnt,
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void **line_info, __u32 *cnt);
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LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext);
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LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext);
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struct btf_dedup_opts {
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unsigned int dedup_table_size;
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bool dont_resolve_fwds;
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};
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LIBBPF_API int btf__dedup(struct btf *btf, struct btf_ext *btf_ext,
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const struct btf_dedup_opts *opts);
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#ifdef __cplusplus
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} /* extern "C" */
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#endif
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#endif /* __LIBBPF_BTF_H */
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