mirror of
https://github.com/torvalds/linux
synced 2024-07-25 12:42:37 +00:00
ec6209c8d4
This patch adds support for the proposed type match relation to
relo_core where it is shared between userspace and kernel. It plumbs
through both kernel-side and libbpf-side support.
The matching relation is defined as follows (copy from source):
- modifiers and typedefs are stripped (and, hence, effectively ignored)
- generally speaking types need to be of same kind (struct vs. struct, union
vs. union, etc.)
- exceptions are struct/union behind a pointer which could also match a
forward declaration of a struct or union, respectively, and enum vs.
enum64 (see below)
Then, depending on type:
- integers:
- match if size and signedness match
- arrays & pointers:
- target types are recursively matched
- structs & unions:
- local members need to exist in target with the same name
- for each member we recursively check match unless it is already behind a
pointer, in which case we only check matching names and compatible kind
- enums:
- local variants have to have a match in target by symbolic name (but not
numeric value)
- size has to match (but enum may match enum64 and vice versa)
- function pointers:
- number and position of arguments in local type has to match target
- for each argument and the return value we recursively check match
Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220628160127.607834-5-deso@posteo.net
100 lines
3.3 KiB
C
100 lines
3.3 KiB
C
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
|
|
/* Copyright (c) 2019 Facebook */
|
|
|
|
#ifndef __RELO_CORE_H
|
|
#define __RELO_CORE_H
|
|
|
|
#include <linux/bpf.h>
|
|
|
|
struct bpf_core_cand {
|
|
const struct btf *btf;
|
|
__u32 id;
|
|
};
|
|
|
|
/* dynamically sized list of type IDs and its associated struct btf */
|
|
struct bpf_core_cand_list {
|
|
struct bpf_core_cand *cands;
|
|
int len;
|
|
};
|
|
|
|
#define BPF_CORE_SPEC_MAX_LEN 64
|
|
|
|
/* represents BPF CO-RE field or array element accessor */
|
|
struct bpf_core_accessor {
|
|
__u32 type_id; /* struct/union type or array element type */
|
|
__u32 idx; /* field index or array index */
|
|
const char *name; /* field name or NULL for array accessor */
|
|
};
|
|
|
|
struct bpf_core_spec {
|
|
const struct btf *btf;
|
|
/* high-level spec: named fields and array indices only */
|
|
struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN];
|
|
/* original unresolved (no skip_mods_or_typedefs) root type ID */
|
|
__u32 root_type_id;
|
|
/* CO-RE relocation kind */
|
|
enum bpf_core_relo_kind relo_kind;
|
|
/* high-level spec length */
|
|
int len;
|
|
/* raw, low-level spec: 1-to-1 with accessor spec string */
|
|
int raw_spec[BPF_CORE_SPEC_MAX_LEN];
|
|
/* raw spec length */
|
|
int raw_len;
|
|
/* field bit offset represented by spec */
|
|
__u32 bit_offset;
|
|
};
|
|
|
|
struct bpf_core_relo_res {
|
|
/* expected value in the instruction, unless validate == false */
|
|
__u64 orig_val;
|
|
/* new value that needs to be patched up to */
|
|
__u64 new_val;
|
|
/* relocation unsuccessful, poison instruction, but don't fail load */
|
|
bool poison;
|
|
/* some relocations can't be validated against orig_val */
|
|
bool validate;
|
|
/* for field byte offset relocations or the forms:
|
|
* *(T *)(rX + <off>) = rY
|
|
* rX = *(T *)(rY + <off>),
|
|
* we remember original and resolved field size to adjust direct
|
|
* memory loads of pointers and integers; this is necessary for 32-bit
|
|
* host kernel architectures, but also allows to automatically
|
|
* relocate fields that were resized from, e.g., u32 to u64, etc.
|
|
*/
|
|
bool fail_memsz_adjust;
|
|
__u32 orig_sz;
|
|
__u32 orig_type_id;
|
|
__u32 new_sz;
|
|
__u32 new_type_id;
|
|
};
|
|
|
|
int __bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
|
|
const struct btf *targ_btf, __u32 targ_id, int level);
|
|
int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
|
|
const struct btf *targ_btf, __u32 targ_id);
|
|
int __bpf_core_types_match(const struct btf *local_btf, __u32 local_id, const struct btf *targ_btf,
|
|
__u32 targ_id, bool behind_ptr, int level);
|
|
int bpf_core_types_match(const struct btf *local_btf, __u32 local_id, const struct btf *targ_btf,
|
|
__u32 targ_id);
|
|
|
|
size_t bpf_core_essential_name_len(const char *name);
|
|
|
|
int bpf_core_calc_relo_insn(const char *prog_name,
|
|
const struct bpf_core_relo *relo, int relo_idx,
|
|
const struct btf *local_btf,
|
|
struct bpf_core_cand_list *cands,
|
|
struct bpf_core_spec *specs_scratch,
|
|
struct bpf_core_relo_res *targ_res);
|
|
|
|
int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
|
|
int insn_idx, const struct bpf_core_relo *relo,
|
|
int relo_idx, const struct bpf_core_relo_res *res);
|
|
|
|
int bpf_core_parse_spec(const char *prog_name, const struct btf *btf,
|
|
const struct bpf_core_relo *relo,
|
|
struct bpf_core_spec *spec);
|
|
|
|
int bpf_core_format_spec(char *buf, size_t buf_sz, const struct bpf_core_spec *spec);
|
|
|
|
#endif
|