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adb8fa195e
BTFGen needs to run the core relocation logic in order to understand what are the types involved in a given relocation. Currently bpf_core_apply_relo() calculates and **applies** a relocation to an instruction. Having both operations in the same function makes it difficult to only calculate the relocation without patching the instruction. This commit splits that logic in two different phases: (1) calculate the relocation and (2) patch the instruction. For the first phase bpf_core_apply_relo() is renamed to bpf_core_calc_relo_insn() who is now only on charge of calculating the relocation, the second phase uses the already existing bpf_core_patch_insn(). bpf_object__relocate_core() uses both of them and the BTFGen will use only bpf_core_calc_relo_insn(). Signed-off-by: Mauricio Vásquez <mauricio@kinvolk.io> Signed-off-by: Rafael David Tinoco <rafael.tinoco@aquasec.com> Signed-off-by: Lorenzo Fontana <lorenzo.fontana@elastic.co> Signed-off-by: Leonardo Di Donato <leonardo.didonato@elastic.co> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220215225856.671072-2-mauricio@kinvolk.io
87 lines
2.6 KiB
C
87 lines
2.6 KiB
C
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
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/* Copyright (c) 2019 Facebook */
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#ifndef __RELO_CORE_H
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#define __RELO_CORE_H
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#include <linux/bpf.h>
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struct bpf_core_cand {
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const struct btf *btf;
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__u32 id;
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};
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/* dynamically sized list of type IDs and its associated struct btf */
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struct bpf_core_cand_list {
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struct bpf_core_cand *cands;
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int len;
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};
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#define BPF_CORE_SPEC_MAX_LEN 64
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/* represents BPF CO-RE field or array element accessor */
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struct bpf_core_accessor {
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__u32 type_id; /* struct/union type or array element type */
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__u32 idx; /* field index or array index */
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const char *name; /* field name or NULL for array accessor */
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};
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struct bpf_core_spec {
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const struct btf *btf;
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/* high-level spec: named fields and array indices only */
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struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN];
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/* original unresolved (no skip_mods_or_typedefs) root type ID */
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__u32 root_type_id;
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/* CO-RE relocation kind */
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enum bpf_core_relo_kind relo_kind;
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/* high-level spec length */
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int len;
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/* raw, low-level spec: 1-to-1 with accessor spec string */
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int raw_spec[BPF_CORE_SPEC_MAX_LEN];
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/* raw spec length */
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int raw_len;
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/* field bit offset represented by spec */
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__u32 bit_offset;
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};
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struct bpf_core_relo_res {
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/* expected value in the instruction, unless validate == false */
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__u32 orig_val;
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/* new value that needs to be patched up to */
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__u32 new_val;
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/* relocation unsuccessful, poison instruction, but don't fail load */
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bool poison;
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/* some relocations can't be validated against orig_val */
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bool validate;
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/* for field byte offset relocations or the forms:
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* *(T *)(rX + <off>) = rY
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* rX = *(T *)(rY + <off>),
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* we remember original and resolved field size to adjust direct
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* memory loads of pointers and integers; this is necessary for 32-bit
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* host kernel architectures, but also allows to automatically
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* relocate fields that were resized from, e.g., u32 to u64, etc.
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*/
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bool fail_memsz_adjust;
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__u32 orig_sz;
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__u32 orig_type_id;
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__u32 new_sz;
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__u32 new_type_id;
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};
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int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
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const struct btf *targ_btf, __u32 targ_id);
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size_t bpf_core_essential_name_len(const char *name);
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int bpf_core_calc_relo_insn(const char *prog_name,
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const struct bpf_core_relo *relo, int relo_idx,
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const struct btf *local_btf,
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struct bpf_core_cand_list *cands,
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struct bpf_core_spec *specs_scratch,
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struct bpf_core_relo_res *targ_res);
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int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
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int insn_idx, const struct bpf_core_relo *relo,
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int relo_idx, const struct bpf_core_relo_res *res);
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#endif
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