linux/tools/lib/bpf/bpf_gen_internal.h
Kumar Kartikeya Dwivedi 18f4fccbf3 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
2021-10-05 17:07:42 -07:00

56 lines
1.5 KiB
C

/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
/* Copyright (c) 2021 Facebook */
#ifndef __BPF_GEN_INTERNAL_H
#define __BPF_GEN_INTERNAL_H
struct ksym_relo_desc {
const char *name;
int kind;
int insn_idx;
bool is_weak;
};
struct ksym_desc {
const char *name;
int ref;
int kind;
int off;
int insn;
};
struct bpf_gen {
struct gen_loader_opts *opts;
void *data_start;
void *data_cur;
void *insn_start;
void *insn_cur;
ssize_t cleanup_label;
__u32 nr_progs;
__u32 nr_maps;
int log_level;
int error;
struct ksym_relo_desc *relos;
int relo_cnt;
char attach_target[128];
int attach_kind;
struct ksym_desc *ksyms;
__u32 nr_ksyms;
int fd_array;
int nr_fd_array;
};
void bpf_gen__init(struct bpf_gen *gen, int log_level);
int bpf_gen__finish(struct bpf_gen *gen);
void bpf_gen__free(struct bpf_gen *gen);
void bpf_gen__load_btf(struct bpf_gen *gen, const void *raw_data, __u32 raw_size);
void bpf_gen__map_create(struct bpf_gen *gen, struct bpf_create_map_attr *map_attr, int map_idx);
struct bpf_prog_load_params;
void bpf_gen__prog_load(struct bpf_gen *gen, struct bpf_prog_load_params *load_attr, int prog_idx);
void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *value, __u32 value_size);
void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx);
void bpf_gen__record_attach_target(struct bpf_gen *gen, const char *name, enum bpf_attach_type type);
void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, int kind,
int insn_idx);
#endif