From 3ee4f5335511b5357d3e762b3461b0d13e565ad5 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Tue, 20 Jul 2021 17:08:20 -0700 Subject: [PATCH] libbpf: Split bpf_core_apply_relo() into bpf_program independent helper. bpf_core_apply_relo() doesn't need to know bpf_program internals and hashmap details. Signed-off-by: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210721000822.40958-3-alexei.starovoitov@gmail.com --- tools/lib/bpf/libbpf.c | 117 +++++++++++++++++++++++++---------------- 1 file changed, 71 insertions(+), 46 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 66e9c9e55444..8649f657e81c 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5972,26 +5972,13 @@ static int insn_bytes_to_bpf_size(__u32 sz) * 5. *(T *)(rX + ) = rY, where T is one of {u8, u16, u32, u64}; * 6. *(T *)(rX + ) = , where T is one of {u8, u16, u32, u64}. */ -static int bpf_core_patch_insn(struct bpf_program *prog, - const struct bpf_core_relo *relo, - int relo_idx, - const struct bpf_core_relo_res *res) +static 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) { - const char *prog_name = prog->name; __u32 orig_val, new_val; - struct bpf_insn *insn; - int insn_idx; __u8 class; - if (relo->insn_off % BPF_INSN_SZ) - return -EINVAL; - insn_idx = relo->insn_off / BPF_INSN_SZ; - /* adjust insn_idx from section frame of reference to the local - * program's frame of reference; (sub-)program code is not yet - * relocated, so it's enough to just subtract in-section offset - */ - insn_idx = insn_idx - prog->sec_insn_off; - insn = &prog->insns[insn_idx]; class = BPF_CLASS(insn->code); if (res->poison) { @@ -6077,7 +6064,6 @@ poison: if (!is_ldimm64_insn(insn) || insn[0].src_reg != 0 || insn[0].off != 0 || - insn_idx + 1 >= prog->insns_cnt || insn[1].code != 0 || insn[1].dst_reg != 0 || insn[1].src_reg != 0 || insn[1].off != 0) { pr_warn("prog '%s': relo #%d: insn #%d (LDIMM64) has unexpected form\n", @@ -6227,19 +6213,17 @@ static void *u32_as_hash_key(__u32 x) * between multiple relocations for the same type ID and is updated as some * of the candidates are pruned due to structural incompatibility. */ -static int bpf_core_apply_relo(struct bpf_program *prog, - const struct bpf_core_relo *relo, - int relo_idx, - const struct btf *local_btf, - struct hashmap *cand_cache) +static int bpf_core_apply_relo_insn(const char *prog_name, struct bpf_insn *insn, + int insn_idx, + const struct bpf_core_relo *relo, + int relo_idx, + const struct btf *local_btf, + struct core_cand_list *cands) { struct bpf_core_spec local_spec, cand_spec, targ_spec = {}; - const void *type_key = u32_as_hash_key(relo->type_id); struct bpf_core_relo_res cand_res, targ_res; const struct btf_type *local_type; const char *local_name; - struct core_cand_list *cands = NULL; - const char *prog_name = prog->name; __u32 local_id; const char *spec_str; int i, j, err; @@ -6257,12 +6241,6 @@ static int bpf_core_apply_relo(struct bpf_program *prog, if (str_is_empty(spec_str)) return -EINVAL; - if (prog->obj->gen_loader) { - pr_warn("// TODO core_relo: prog %td insn[%d] %s %s kind %d\n", - prog - prog->obj->programs, relo->insn_off / 8, - local_name, spec_str, relo->kind); - return -ENOTSUP; - } err = bpf_core_parse_spec(local_btf, local_id, spec_str, relo->kind, &local_spec); if (err) { pr_warn("prog '%s': relo #%d: parsing [%d] %s %s + %s failed: %d\n", @@ -6293,20 +6271,6 @@ static int bpf_core_apply_relo(struct bpf_program *prog, return -EOPNOTSUPP; } - if (!hashmap__find(cand_cache, type_key, (void **)&cands)) { - cands = bpf_core_find_cands(prog->obj, local_btf, local_id); - if (IS_ERR(cands)) { - pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n", - prog_name, relo_idx, local_id, btf_kind_str(local_type), - local_name, PTR_ERR(cands)); - return PTR_ERR(cands); - } - err = hashmap__set(cand_cache, type_key, cands, NULL, NULL); - if (err) { - bpf_core_free_cands(cands); - return err; - } - } for (i = 0, j = 0; i < cands->len; i++) { err = bpf_core_spec_match(&local_spec, cands->cands[i].btf, @@ -6391,7 +6355,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog, patch_insn: /* bpf_core_patch_insn() should know how to handle missing targ_spec */ - err = bpf_core_patch_insn(prog, relo, relo_idx, &targ_res); + err = bpf_core_patch_insn(prog_name, insn, insn_idx, relo, relo_idx, &targ_res); if (err) { pr_warn("prog '%s': relo #%d: failed to patch insn #%zu: %d\n", prog_name, relo_idx, relo->insn_off / BPF_INSN_SZ, err); @@ -6401,6 +6365,67 @@ patch_insn: return 0; } +static int bpf_core_apply_relo(struct bpf_program *prog, + const struct bpf_core_relo *relo, + int relo_idx, + const struct btf *local_btf, + struct hashmap *cand_cache) +{ + const void *type_key = u32_as_hash_key(relo->type_id); + struct core_cand_list *cands = NULL; + const char *prog_name = prog->name; + const struct btf_type *local_type; + const char *local_name; + __u32 local_id = relo->type_id; + struct bpf_insn *insn; + int insn_idx, err; + + if (relo->insn_off % BPF_INSN_SZ) + return -EINVAL; + insn_idx = relo->insn_off / BPF_INSN_SZ; + /* adjust insn_idx from section frame of reference to the local + * program's frame of reference; (sub-)program code is not yet + * relocated, so it's enough to just subtract in-section offset + */ + insn_idx = insn_idx - prog->sec_insn_off; + if (insn_idx > prog->insns_cnt) + return -EINVAL; + insn = &prog->insns[insn_idx]; + + local_type = btf__type_by_id(local_btf, local_id); + if (!local_type) + return -EINVAL; + + local_name = btf__name_by_offset(local_btf, local_type->name_off); + if (!local_name) + return -EINVAL; + + if (prog->obj->gen_loader) { + pr_warn("// TODO core_relo: prog %td insn[%d] %s kind %d\n", + prog - prog->obj->programs, relo->insn_off / 8, + local_name, relo->kind); + return -ENOTSUP; + } + + if (relo->kind != BPF_TYPE_ID_LOCAL && + !hashmap__find(cand_cache, type_key, (void **)&cands)) { + cands = bpf_core_find_cands(prog->obj, local_btf, local_id); + if (IS_ERR(cands)) { + pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n", + prog_name, relo_idx, local_id, btf_kind_str(local_type), + local_name, PTR_ERR(cands)); + return PTR_ERR(cands); + } + err = hashmap__set(cand_cache, type_key, cands, NULL, NULL); + if (err) { + bpf_core_free_cands(cands); + return err; + } + } + + return bpf_core_apply_relo_insn(prog_name, insn, insn_idx, relo, relo_idx, local_btf, cands); +} + static int bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) { -- 2.25.1