Commit 5ad0ecbe authored by Eduard Zingerman's avatar Eduard Zingerman Committed by Andrii Nakryiko
Browse files

libbpf: Struct_ops in SEC("?.struct_ops") / SEC("?.struct_ops.link") 



Allow using two new section names for struct_ops maps:
- SEC("?.struct_ops")
- SEC("?.struct_ops.link")

To specify maps that have bpf_map->autocreate == false after open.

Signed-off-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240306104529.6453-12-eddyz87@gmail.com
parent 240bf8a5

tools/lib/bpf/libbpf.c

+14 −1
Original line number Diff line number Diff line
@@ -1322,6 +1322,15 @@ static int init_struct_ops_maps(struct bpf_object *obj, const char *sec_name, 
			return -ENOMEM;

		map->btf_value_type_id = type_id;



		/* Follow same convention as for programs autoload:

		 * SEC("?.struct_ops") means map is not created by default.

		 */

		if (sec_name[0] == '?') {

			map->autocreate = false;

			/* from now on forget there was ? in section name */

			sec_name++;

		}



		map->def.type = BPF_MAP_TYPE_STRUCT_OPS;

		map->def.key_size = sizeof(int);

		map->def.value_size = type->size;
@@ -3685,7 +3694,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj) 
				sec_desc->shdr = sh;

				sec_desc->data = data;

			} else if (strcmp(name, STRUCT_OPS_SEC) == 0 ||

				   strcmp(name, STRUCT_OPS_LINK_SEC) == 0) {

				   strcmp(name, STRUCT_OPS_LINK_SEC) == 0 ||

				   strcmp(name, "?" STRUCT_OPS_SEC) == 0 ||

				   strcmp(name, "?" STRUCT_OPS_LINK_SEC) == 0) {

				sec_desc->sec_type = SEC_ST_OPS;

				sec_desc->shdr = sh;

				sec_desc->data = data;
@@ -3705,6 +3716,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj) 
			if (!section_have_execinstr(obj, targ_sec_idx) &&

			    strcmp(name, ".rel" STRUCT_OPS_SEC) &&

			    strcmp(name, ".rel" STRUCT_OPS_LINK_SEC) &&

			    strcmp(name, ".rel?" STRUCT_OPS_SEC) &&

			    strcmp(name, ".rel?" STRUCT_OPS_LINK_SEC) &&

			    strcmp(name, ".rel" MAPS_ELF_SEC)) {

				pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n",

					idx, name, targ_sec_idx,