Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2021-04-01

The following pull-request contains BPF updates for your *net-next* tree.

We've added 68 non-merge commits during the last 7 day(s) which contain
a total of 70 files changed, 2944 insertions(+), 1139 deletions(-).

The main changes are:

1) UDP support for sockmap, from Cong.

2) Verifier merge conflict resolution fix, from Daniel.

3) xsk selftests enhancements, from Maciej.

4) Unstable helpers aka kernel func calling, from Martin.

5) Batches ops for LPM map, from Pedro.

6) Fix race in bpf_get_local_storage, from Yonghong.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 300 insertions, 103 deletions

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index c0fd2c718a7d..7aad78dbb4b4 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -185,7 +185,8 @@ enum reloc_type {
 	RELO_LD64,
 	RELO_CALL,
 	RELO_DATA,
-	RELO_EXTERN,
+	RELO_EXTERN_VAR,
+	RELO_EXTERN_FUNC,
 	RELO_SUBPROG_ADDR,
 };
 
@@ -573,14 +574,19 @@ static bool insn_is_subprog_call(const struct bpf_insn *insn)
 	       insn->off == 0;
 }
 
-static bool is_ldimm64(struct bpf_insn *insn)
+static bool is_ldimm64_insn(struct bpf_insn *insn)
 {
 	return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
 }
 
+static bool is_call_insn(const struct bpf_insn *insn)
+{
+	return insn->code == (BPF_JMP | BPF_CALL);
+}
+
 static bool insn_is_pseudo_func(struct bpf_insn *insn)
 {
-	return is_ldimm64(insn) && insn->src_reg == BPF_PSEUDO_FUNC;
+	return is_ldimm64_insn(insn) && insn->src_reg == BPF_PSEUDO_FUNC;
 }
 
 static int
@@ -1921,9 +1927,9 @@ resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id)
 	return btf_is_func_proto(t) ? t : NULL;
 }
 
-static const char *btf_kind_str(const struct btf_type *t)
+static const char *__btf_kind_str(__u16 kind)
 {
-	switch (btf_kind(t)) {
+	switch (kind) {
 	case BTF_KIND_UNKN: return "void";
 	case BTF_KIND_INT: return "int";
 	case BTF_KIND_PTR: return "ptr";
@@ -1945,6 +1951,16 @@ static const char *btf_kind_str(const struct btf_type *t)
 	}
 }
 
+static const char *btf_kind_str(const struct btf_type *t)
+{
+	return __btf_kind_str(btf_kind(t));
+}
+
+static enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
+{
+	return (enum btf_func_linkage)BTF_INFO_VLEN(t->info);
+}
+
 /*
  * Fetch integer attribute of BTF map definition. Such attributes are
  * represented using a pointer to an array, in which dimensionality of array
@@ -3009,7 +3025,7 @@ static bool sym_is_subprog(const GElf_Sym *sym, int text_shndx)
 static int find_extern_btf_id(const struct btf *btf, const char *ext_name)
 {
 	const struct btf_type *t;
-	const char *var_name;
+	const char *tname;
 	int i, n;
 
 	if (!btf)
@@ -3019,14 +3035,18 @@ static int find_extern_btf_id(const struct btf *btf, const char *ext_name)
 	for (i = 1; i <= n; i++) {
 		t = btf__type_by_id(btf, i);
 
-		if (!btf_is_var(t))
+		if (!btf_is_var(t) && !btf_is_func(t))
 			continue;
 
-		var_name = btf__name_by_offset(btf, t->name_off);
-		if (strcmp(var_name, ext_name))
+		tname = btf__name_by_offset(btf, t->name_off);
+		if (strcmp(tname, ext_name))
 			continue;
 
-		if (btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN)
+		if (btf_is_var(t) &&
+		    btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN)
+			return -EINVAL;
+
+		if (btf_is_func(t) && btf_func_linkage(t) != BTF_FUNC_EXTERN)
 			return -EINVAL;
 
 		return i;
@@ -3139,12 +3159,48 @@ static int find_int_btf_id(const struct btf *btf)
 	return 0;
 }
 
+static int add_dummy_ksym_var(struct btf *btf)
+{
+	int i, int_btf_id, sec_btf_id, dummy_var_btf_id;
+	const struct btf_var_secinfo *vs;
+	const struct btf_type *sec;
+
+	sec_btf_id = btf__find_by_name_kind(btf, KSYMS_SEC,
+					    BTF_KIND_DATASEC);
+	if (sec_btf_id < 0)
+		return 0;
+
+	sec = btf__type_by_id(btf, sec_btf_id);
+	vs = btf_var_secinfos(sec);
+	for (i = 0; i < btf_vlen(sec); i++, vs++) {
+		const struct btf_type *vt;
+
+		vt = btf__type_by_id(btf, vs->type);
+		if (btf_is_func(vt))
+			break;
+	}
+
+	/* No func in ksyms sec.  No need to add dummy var. */
+	if (i == btf_vlen(sec))
+		return 0;
+
+	int_btf_id = find_int_btf_id(btf);
+	dummy_var_btf_id = btf__add_var(btf,
+					"dummy_ksym",
+					BTF_VAR_GLOBAL_ALLOCATED,
+					int_btf_id);
+	if (dummy_var_btf_id < 0)
+		pr_warn("cannot create a dummy_ksym var\n");
+
+	return dummy_var_btf_id;
+}
+
 static int bpf_object__collect_externs(struct bpf_object *obj)
 {
 	struct btf_type *sec, *kcfg_sec = NULL, *ksym_sec = NULL;
 	const struct btf_type *t;
 	struct extern_desc *ext;
-	int i, n, off;
+	int i, n, off, dummy_var_btf_id;
 	const char *ext_name, *sec_name;
 	Elf_Scn *scn;
 	GElf_Shdr sh;
@@ -3156,6 +3212,10 @@ static int bpf_object__collect_externs(struct bpf_object *obj)
 	if (elf_sec_hdr(obj, scn, &sh))
 		return -LIBBPF_ERRNO__FORMAT;
 
+	dummy_var_btf_id = add_dummy_ksym_var(obj->btf);
+	if (dummy_var_btf_id < 0)
+		return dummy_var_btf_id;
+
 	n = sh.sh_size / sh.sh_entsize;
 	pr_debug("looking for externs among %d symbols...\n", n);
 
@@ -3200,6 +3260,11 @@ static int bpf_object__collect_externs(struct bpf_object *obj)
 		sec_name = btf__name_by_offset(obj->btf, sec->name_off);
 
 		if (strcmp(sec_name, KCONFIG_SEC) == 0) {
+			if (btf_is_func(t)) {
+				pr_warn("extern function %s is unsupported under %s section\n",
+					ext->name, KCONFIG_SEC);
+				return -ENOTSUP;
+			}
 			kcfg_sec = sec;
 			ext->type = EXT_KCFG;
 			ext->kcfg.sz = btf__resolve_size(obj->btf, t->type);
@@ -3221,6 +3286,11 @@ static int bpf_object__collect_externs(struct bpf_object *obj)
 				return -ENOTSUP;
 			}
 		} else if (strcmp(sec_name, KSYMS_SEC) == 0) {
+			if (btf_is_func(t) && ext->is_weak) {
+				pr_warn("extern weak function %s is unsupported\n",
+					ext->name);
+				return -ENOTSUP;
+			}
 			ksym_sec = sec;
 			ext->type = EXT_KSYM;
 			skip_mods_and_typedefs(obj->btf, t->type,
@@ -3247,7 +3317,14 @@ static int bpf_object__collect_externs(struct bpf_object *obj)
 		 * extern variables in DATASEC
 		 */
 		int int_btf_id = find_int_btf_id(obj->btf);
+		/* For extern function, a dummy_var added earlier
+		 * will be used to replace the vs->type and
+		 * its name string will be used to refill
+		 * the missing param's name.
+		 */
+		const struct btf_type *dummy_var;
 
+		dummy_var = btf__type_by_id(obj->btf, dummy_var_btf_id);
 		for (i = 0; i < obj->nr_extern; i++) {
 			ext = &obj->externs[i];
 			if (ext->type != EXT_KSYM)
@@ -3266,12 +3343,32 @@ static int bpf_object__collect_externs(struct bpf_object *obj)
 			ext_name = btf__name_by_offset(obj->btf, vt->name_off);
 			ext = find_extern_by_name(obj, ext_name);
 			if (!ext) {
-				pr_warn("failed to find extern definition for BTF var '%s'\n",
-					ext_name);
+				pr_warn("failed to find extern definition for BTF %s '%s'\n",
+					btf_kind_str(vt), ext_name);
 				return -ESRCH;
 			}
-			btf_var(vt)->linkage = BTF_VAR_GLOBAL_ALLOCATED;
-			vt->type = int_btf_id;
+			if (btf_is_func(vt)) {
+				const struct btf_type *func_proto;
+				struct btf_param *param;
+				int j;
+
+				func_proto = btf__type_by_id(obj->btf,
+							     vt->type);
+				param = btf_params(func_proto);
+				/* Reuse the dummy_var string if the
+				 * func proto does not have param name.
+				 */
+				for (j = 0; j < btf_vlen(func_proto); j++)
+					if (param[j].type && !param[j].name_off)
+						param[j].name_off =
+							dummy_var->name_off;
+				vs->type = dummy_var_btf_id;
+				vt->info &= ~0xffff;
+				vt->info |= BTF_FUNC_GLOBAL;
+			} else {
+				btf_var(vt)->linkage = BTF_VAR_GLOBAL_ALLOCATED;
+				vt->type = int_btf_id;
+			}
 			vs->offset = off;
 			vs->size = sizeof(int);
 		}
@@ -3403,31 +3500,7 @@ static int bpf_program__record_reloc(struct bpf_program *prog,
 
 	reloc_desc->processed = false;
 
-	/* sub-program call relocation */
-	if (insn->code == (BPF_JMP | BPF_CALL)) {
-		if (insn->src_reg != BPF_PSEUDO_CALL) {
-			pr_warn("prog '%s': incorrect bpf_call opcode\n", prog->name);
-			return -LIBBPF_ERRNO__RELOC;
-		}
-		/* text_shndx can be 0, if no default "main" program exists */
-		if (!shdr_idx || shdr_idx != obj->efile.text_shndx) {
-			sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx));
-			pr_warn("prog '%s': bad call relo against '%s' in section '%s'\n",
-				prog->name, sym_name, sym_sec_name);
-			return -LIBBPF_ERRNO__RELOC;
-		}
-		if (sym->st_value % BPF_INSN_SZ) {
-			pr_warn("prog '%s': bad call relo against '%s' at offset %zu\n",
-				prog->name, sym_name, (size_t)sym->st_value);
-			return -LIBBPF_ERRNO__RELOC;
-		}
-		reloc_desc->type = RELO_CALL;
-		reloc_desc->insn_idx = insn_idx;
-		reloc_desc->sym_off = sym->st_value;
-		return 0;
-	}
-
-	if (!is_ldimm64(insn)) {
+	if (!is_call_insn(insn) && !is_ldimm64_insn(insn)) {
 		pr_warn("prog '%s': invalid relo against '%s' for insns[%d].code 0x%x\n",
 			prog->name, sym_name, insn_idx, insn->code);
 		return -LIBBPF_ERRNO__RELOC;
@@ -3450,12 +3523,39 @@ static int bpf_program__record_reloc(struct bpf_program *prog,
 		}
 		pr_debug("prog '%s': found extern #%d '%s' (sym %d) for insn #%u\n",
 			 prog->name, i, ext->name, ext->sym_idx, insn_idx);
-		reloc_desc->type = RELO_EXTERN;
+		if (insn->code == (BPF_JMP | BPF_CALL))
+			reloc_desc->type = RELO_EXTERN_FUNC;
+		else
+			reloc_desc->type = RELO_EXTERN_VAR;
 		reloc_desc->insn_idx = insn_idx;
 		reloc_desc->sym_off = i; /* sym_off stores extern index */
 		return 0;
 	}
 
+	/* sub-program call relocation */
+	if (is_call_insn(insn)) {
+		if (insn->src_reg != BPF_PSEUDO_CALL) {
+			pr_warn("prog '%s': incorrect bpf_call opcode\n", prog->name);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		/* text_shndx can be 0, if no default "main" program exists */
+		if (!shdr_idx || shdr_idx != obj->efile.text_shndx) {
+			sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx));
+			pr_warn("prog '%s': bad call relo against '%s' in section '%s'\n",
+				prog->name, sym_name, sym_sec_name);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		if (sym->st_value % BPF_INSN_SZ) {
+			pr_warn("prog '%s': bad call relo against '%s' at offset %zu\n",
+				prog->name, sym_name, (size_t)sym->st_value);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		reloc_desc->type = RELO_CALL;
+		reloc_desc->insn_idx = insn_idx;
+		reloc_desc->sym_off = sym->st_value;
+		return 0;
+	}
+
 	if (!shdr_idx || shdr_idx >= SHN_LORESERVE) {
 		pr_warn("prog '%s': invalid relo against '%s' in special section 0x%x; forgot to initialize global var?..\n",
 			prog->name, sym_name, shdr_idx);
@@ -5695,7 +5795,7 @@ poison:
 		/* poison second part of ldimm64 to avoid confusing error from
 		 * verifier about "unknown opcode 00"
 		 */
-		if (is_ldimm64(insn))
+		if (is_ldimm64_insn(insn))
 			bpf_core_poison_insn(prog, relo_idx, insn_idx + 1, insn + 1);
 		bpf_core_poison_insn(prog, relo_idx, insn_idx, insn);
 		return 0;
@@ -5771,7 +5871,7 @@ poison:
 	case BPF_LD: {
 		__u64 imm;
 
-		if (!is_ldimm64(insn) ||
+		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 ||
@@ -6213,7 +6313,7 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog)
 			insn[0].imm = obj->maps[relo->map_idx].fd;
 			relo->processed = true;
 			break;
-		case RELO_EXTERN:
+		case RELO_EXTERN_VAR:
 			ext = &obj->externs[relo->sym_off];
 			if (ext->type == EXT_KCFG) {
 				insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
@@ -6231,6 +6331,12 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog)
 			}
 			relo->processed = true;
 			break;
+		case RELO_EXTERN_FUNC:
+			ext = &obj->externs[relo->sym_off];
+			insn[0].src_reg = BPF_PSEUDO_KFUNC_CALL;
+			insn[0].imm = ext->ksym.kernel_btf_id;
+			relo->processed = true;
+			break;
 		case RELO_SUBPROG_ADDR:
 			insn[0].src_reg = BPF_PSEUDO_FUNC;
 			/* will be handled as a follow up pass */
@@ -7351,6 +7457,7 @@ static int bpf_object__read_kallsyms_file(struct bpf_object *obj)
 {
 	char sym_type, sym_name[500];
 	unsigned long long sym_addr;
+	const struct btf_type *t;
 	struct extern_desc *ext;
 	int ret, err = 0;
 	FILE *f;
@@ -7377,6 +7484,10 @@ static int bpf_object__read_kallsyms_file(struct bpf_object *obj)
 		if (!ext || ext->type != EXT_KSYM)
 			continue;
 
+		t = btf__type_by_id(obj->btf, ext->btf_id);
+		if (!btf_is_var(t))
+			continue;
+
 		if (ext->is_set && ext->ksym.addr != sym_addr) {
 			pr_warn("extern (ksym) '%s' resolution is ambiguous: 0x%llx or 0x%llx\n",
 				sym_name, ext->ksym.addr, sym_addr);
@@ -7395,75 +7506,151 @@ out:
 	return err;
 }
 
-static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj)
+static int find_ksym_btf_id(struct bpf_object *obj, const char *ksym_name,
+			    __u16 kind, struct btf **res_btf,
+			    int *res_btf_fd)
 {
-	struct extern_desc *ext;
+	int i, id, btf_fd, err;
 	struct btf *btf;
-	int i, j, id, btf_fd, err;
 
-	for (i = 0; i < obj->nr_extern; i++) {
-		const struct btf_type *targ_var, *targ_type;
-		__u32 targ_type_id, local_type_id;
-		const char *targ_var_name;
-		int ret;
+	btf = obj->btf_vmlinux;
+	btf_fd = 0;
+	id = btf__find_by_name_kind(btf, ksym_name, kind);
 
-		ext = &obj->externs[i];
-		if (ext->type != EXT_KSYM || !ext->ksym.type_id)
-			continue;
-
-		btf = obj->btf_vmlinux;
-		btf_fd = 0;
-		id = btf__find_by_name_kind(btf, ext->name, BTF_KIND_VAR);
-		if (id == -ENOENT) {
-			err = load_module_btfs(obj);
-			if (err)
-				return err;
+	if (id == -ENOENT) {
+		err = load_module_btfs(obj);
+		if (err)
+			return err;
 
-			for (j = 0; j < obj->btf_module_cnt; j++) {
-				btf = obj->btf_modules[j].btf;
-				/* we assume module BTF FD is always >0 */
-				btf_fd = obj->btf_modules[j].fd;
-				id = btf__find_by_name_kind(btf, ext->name, BTF_KIND_VAR);
-				if (id != -ENOENT)
-					break;
-			}
-		}
-		if (id <= 0) {
-			pr_warn("extern (ksym) '%s': failed to find BTF ID in kernel BTF(s).\n",
-				ext->name);
-			return -ESRCH;
+		for (i = 0; i < obj->btf_module_cnt; i++) {
+			btf = obj->btf_modules[i].btf;
+			/* we assume module BTF FD is always >0 */
+			btf_fd = obj->btf_modules[i].fd;
+			id = btf__find_by_name_kind(btf, ksym_name, kind);
+			if (id != -ENOENT)
+				break;
 		}
+	}
+	if (id <= 0) {
+		pr_warn("extern (%s ksym) '%s': failed to find BTF ID in kernel BTF(s).\n",
+			__btf_kind_str(kind), ksym_name);
+		return -ESRCH;
+	}
 
-		/* find local type_id */
-		local_type_id = ext->ksym.type_id;
+	*res_btf = btf;
+	*res_btf_fd = btf_fd;
+	return id;
+}
 
-		/* find target type_id */
-		targ_var = btf__type_by_id(btf, id);
-		targ_var_name = btf__name_by_offset(btf, targ_var->name_off);
-		targ_type = skip_mods_and_typedefs(btf, targ_var->type, &targ_type_id);
+static int bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj,
+					       struct extern_desc *ext)
+{
+	const struct btf_type *targ_var, *targ_type;
+	__u32 targ_type_id, local_type_id;
+	const char *targ_var_name;
+	int id, btf_fd = 0, err;
+	struct btf *btf = NULL;
 
-		ret = bpf_core_types_are_compat(obj->btf, local_type_id,
-						btf, targ_type_id);
-		if (ret <= 0) {
-			const struct btf_type *local_type;
-			const char *targ_name, *local_name;
+	id = find_ksym_btf_id(obj, ext->name, BTF_KIND_VAR, &btf, &btf_fd);
+	if (id < 0)
+		return id;
 
-			local_type = btf__type_by_id(obj->btf, local_type_id);
-			local_name = btf__name_by_offset(obj->btf, local_type->name_off);
-			targ_name = btf__name_by_offset(btf, targ_type->name_off);
+	/* find local type_id */
+	local_type_id = ext->ksym.type_id;
 
-			pr_warn("extern (ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n",
-				ext->name, local_type_id,
-				btf_kind_str(local_type), local_name, targ_type_id,
-				btf_kind_str(targ_type), targ_name);
-			return -EINVAL;
-		}
+	/* find target type_id */
+	targ_var = btf__type_by_id(btf, id);
+	targ_var_name = btf__name_by_offset(btf, targ_var->name_off);
+	targ_type = skip_mods_and_typedefs(btf, targ_var->type, &targ_type_id);
+
+	err = bpf_core_types_are_compat(obj->btf, local_type_id,
+					btf, targ_type_id);
+	if (err <= 0) {
+		const struct btf_type *local_type;
+		const char *targ_name, *local_name;
 
-		ext->is_set = true;
-		ext->ksym.kernel_btf_obj_fd = btf_fd;
-		ext->ksym.kernel_btf_id = id;
-		pr_debug("extern (ksym) '%s': resolved to [%d] %s %s\n",
-			 ext->name, id, btf_kind_str(targ_var), targ_var_name);
+		local_type = btf__type_by_id(obj->btf, local_type_id);
+		local_name = btf__name_by_offset(obj->btf, local_type->name_off);
+		targ_name = btf__name_by_offset(btf, targ_type->name_off);
+
+		pr_warn("extern (var ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n",
+			ext->name, local_type_id,
+			btf_kind_str(local_type), local_name, targ_type_id,
+			btf_kind_str(targ_type), targ_name);
+		return -EINVAL;
+	}
+
+	ext->is_set = true;
+	ext->ksym.kernel_btf_obj_fd = btf_fd;
+	ext->ksym.kernel_btf_id = id;
+	pr_debug("extern (var ksym) '%s': resolved to [%d] %s %s\n",
+		 ext->name, id, btf_kind_str(targ_var), targ_var_name);
+
+	return 0;
+}
+
+static int bpf_object__resolve_ksym_func_btf_id(struct bpf_object *obj,
+						struct extern_desc *ext)
+{
+	int local_func_proto_id, kfunc_proto_id, kfunc_id;
+	const struct btf_type *kern_func;
+	struct btf *kern_btf = NULL;
+	int ret, kern_btf_fd = 0;
+
+	local_func_proto_id = ext->ksym.type_id;
+
+	kfunc_id = find_ksym_btf_id(obj, ext->name, BTF_KIND_FUNC,
+				    &kern_btf, &kern_btf_fd);
+	if (kfunc_id < 0) {
+		pr_warn("extern (func ksym) '%s': not found in kernel BTF\n",
+			ext->name);
+		return kfunc_id;
+	}
+
+	if (kern_btf != obj->btf_vmlinux) {
+		pr_warn("extern (func ksym) '%s': function in kernel module is not supported\n",
+			ext->name);
+		return -ENOTSUP;
+	}
+
+	kern_func = btf__type_by_id(kern_btf, kfunc_id);
+	kfunc_proto_id = kern_func->type;
+
+	ret = bpf_core_types_are_compat(obj->btf, local_func_proto_id,
+					kern_btf, kfunc_proto_id);
+	if (ret <= 0) {
+		pr_warn("extern (func ksym) '%s': func_proto [%d] incompatible with kernel [%d]\n",
+			ext->name, local_func_proto_id, kfunc_proto_id);
+		return -EINVAL;
+	}
+
+	ext->is_set = true;
+	ext->ksym.kernel_btf_obj_fd = kern_btf_fd;
+	ext->ksym.kernel_btf_id = kfunc_id;
+	pr_debug("extern (func ksym) '%s': resolved to kernel [%d]\n",
+		 ext->name, kfunc_id);
+
+	return 0;
+}
+
+static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj)
+{
+	const struct btf_type *t;
+	struct extern_desc *ext;
+	int i, err;
+
+	for (i = 0; i < obj->nr_extern; i++) {
+		ext = &obj->externs[i];
+		if (ext->type != EXT_KSYM || !ext->ksym.type_id)
+			continue;
+
+		t = btf__type_by_id(obj->btf, ext->btf_id);
+		if (btf_is_var(t))
+			err = bpf_object__resolve_ksym_var_btf_id(obj, ext);
+		else
+			err = bpf_object__resolve_ksym_func_btf_id(obj, ext);
+		if (err)
+			return err;
 	}
 	return 0;
 }
@@ -8270,6 +8457,16 @@ int bpf_object__btf_fd(const struct bpf_object *obj)
 	return obj->btf ? btf__fd(obj->btf) : -1;
 }
 
+int bpf_object__set_kversion(struct bpf_object *obj, __u32 kern_version)
+{
+	if (obj->loaded)
+		return -EINVAL;
+
+	obj->kern_version = kern_version;
+
+	return 0;
+}
+
 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
 			 bpf_object_clear_priv_t clear_priv)
 {
@@ -8458,7 +8655,7 @@ int bpf_program__nth_fd(const struct bpf_program *prog, int n)
 	return fd;
 }
 
-enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog)
+enum bpf_prog_type bpf_program__get_type(const struct bpf_program *prog)
 {
 	return prog->type;
 }
@@ -8503,7 +8700,7 @@ BPF_PROG_TYPE_FNS(extension, BPF_PROG_TYPE_EXT);
 BPF_PROG_TYPE_FNS(sk_lookup, BPF_PROG_TYPE_SK_LOOKUP);
 
 enum bpf_attach_type
-bpf_program__get_expected_attach_type(struct bpf_program *prog)
+bpf_program__get_expected_attach_type(const struct bpf_program *prog)
 {
 	return prog->expected_attach_type;
 }