2824ecb701
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 38d5d3b3d5 ("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>
73 lines
2.3 KiB
C
73 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (c) 2018 Facebook */
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#ifndef _LINUX_BTF_H
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#define _LINUX_BTF_H 1
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#include <linux/types.h>
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struct btf;
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struct btf_member;
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struct btf_type;
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union bpf_attr;
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extern const struct file_operations btf_fops;
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void btf_put(struct btf *btf);
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int btf_new_fd(const union bpf_attr *attr);
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struct btf *btf_get_by_fd(int fd);
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int btf_get_info_by_fd(const struct btf *btf,
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const union bpf_attr *attr,
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union bpf_attr __user *uattr);
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/* Figure out the size of a type_id. If type_id is a modifier
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* (e.g. const), it will be resolved to find out the type with size.
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*
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* For example:
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* In describing "const void *", type_id is "const" and "const"
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* refers to "void *". The return type will be "void *".
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*
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* If type_id is a simple "int", then return type will be "int".
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*
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* @btf: struct btf object
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* @type_id: Find out the size of type_id. The type_id of the return
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* type is set to *type_id.
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* @ret_size: It can be NULL. If not NULL, the size of the return
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* type is set to *ret_size.
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* Return: The btf_type (resolved to another type with size info if needed).
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* NULL is returned if type_id itself does not have size info
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* (e.g. void) or it cannot be resolved to another type that
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* has size info.
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* *type_id and *ret_size will not be changed in the
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* NULL return case.
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*/
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const struct btf_type *btf_type_id_size(const struct btf *btf,
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u32 *type_id,
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u32 *ret_size);
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void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
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struct seq_file *m);
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int btf_get_fd_by_id(u32 id);
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u32 btf_id(const struct btf *btf);
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bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
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const struct btf_member *m,
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u32 expected_offset, u32 expected_size);
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int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t);
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bool btf_type_is_void(const struct btf_type *t);
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#ifdef CONFIG_BPF_SYSCALL
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const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
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const char *btf_name_by_offset(const struct btf *btf, u32 offset);
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#else
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static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
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u32 type_id)
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{
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return NULL;
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}
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static inline const char *btf_name_by_offset(const struct btf *btf,
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u32 offset)
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{
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return NULL;
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}
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#endif
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#endif
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