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d29d87f7e6
This change splits out previous btf__new functionality of constructing
struct btf and loading it into kernel into two:
- btf__new() just creates and initializes struct btf
- btf__load() attempts to load existing struct btf into kernel
btf__free will still close BTF fd, if it was ever loaded successfully
into kernel.
This change allows users of libbpf to manipulate BTF using its API,
without the need to unnecessarily load it into kernel.
One of the intended use cases is pahole, which will do DWARF to BTF
conversion and then use libbpf to do type deduplication, while then
handling ELF sections overwriting and other concerns on its own.
Fixes: 2d3feca8c4 ("bpf: btf: print map dump and lookup with btf info")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
102 lines
3.3 KiB
C
102 lines
3.3 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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/*
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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__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 void btf__get_strings(const struct btf *btf, const char **strings,
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__u32 *str_len);
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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 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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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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