Commit 3ee4f533 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Andrii Nakryiko
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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: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210721000822.40958-3-alexei.starovoitov@gmail.com
parent 6e43b286

tools/lib/bpf/libbpf.c

+71 −46
Original line number Diff line number Diff line
@@ -5972,26 +5972,13 @@ static int insn_bytes_to_bpf_size(__u32 sz) 
 * 5. *(T *)(rX + <off>) = rY, where T is one of {u8, u16, u32, u64};

 * 6. *(T *)(rX + <off>) = <imm>, 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 @@ static int bpf_core_patch_insn(struct bpf_program *prog, 


		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,

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 hashmap *cand_cache)

				    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 @@ static int bpf_core_apply_relo(struct bpf_program *prog, 
	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)

{