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From: Eduard Zingerman <eddyz87@gmail.com>
To: bpf@vger.kernel.org, ast@kernel.org
Cc: andrii@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev,
	kernel-team@fb.com, yonghong.song@linux.dev, void@manifault.com,
	sinquersw@gmail.com, Eduard Zingerman <eddyz87@gmail.com>
Subject: [PATCH bpf-next v2 11/15] libbpf: struct_ops in SEC("?.struct_ops") and SEC("?.struct_ops.link")
Date: Sat,  2 Mar 2024 03:19:16 +0200	[thread overview]
Message-ID: <20240302011920.15302-12-eddyz87@gmail.com> (raw)
In-Reply-To: <20240302011920.15302-1-eddyz87@gmail.com>

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: Eduard Zingerman <eddyz87@gmail.com>
---
 tools/lib/bpf/libbpf.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 8ecfad091cb5..157d28aea186 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -497,6 +497,8 @@ struct bpf_struct_ops {
 #define KSYMS_SEC ".ksyms"
 #define STRUCT_OPS_SEC ".struct_ops"
 #define STRUCT_OPS_LINK_SEC ".struct_ops.link"
+#define OPT_STRUCT_OPS_SEC "?.struct_ops"
+#define OPT_STRUCT_OPS_LINK_SEC "?.struct_ops.link"
 
 enum libbpf_map_type {
 	LIBBPF_MAP_UNSPEC,
@@ -1278,6 +1280,15 @@ 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;
@@ -3647,7 +3658,9 @@ 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, OPT_STRUCT_OPS_SEC) == 0 ||
+				   strcmp(name, OPT_STRUCT_OPS_LINK_SEC) == 0) {
 				sec_desc->sec_type = SEC_ST_OPS;
 				sec_desc->shdr = sh;
 				sec_desc->data = data;
@@ -3667,6 +3680,8 @@ 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" OPT_STRUCT_OPS_SEC) &&
+			    strcmp(name, ".rel" OPT_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,
-- 
2.43.0


  parent reply	other threads:[~2024-03-02  1:19 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-02  1:19 [PATCH bpf-next v2 00/15] libbpf: type suffixes and autocreate flag for struct_ops maps Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 01/15] libbpf: allow version suffixes (___smth) for struct_ops types Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 02/15] libbpf: tie struct_ops programs to kernel BTF ids, not to local ids Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 03/15] libbpf: honor autocreate flag for struct_ops maps Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 04/15] selftests/bpf: test struct_ops map definition with type suffix Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 05/15] selftests/bpf: utility functions to capture libbpf log in test_progs Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 06/15] selftests/bpf: bad_struct_ops test Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 07/15] selftests/bpf: test autocreate behavior for struct_ops maps Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 08/15] libbpf: sync progs autoload with maps autocreate " Eduard Zingerman
2024-03-04 19:13   ` Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 09/15] selftests/bpf: verify struct_ops autoload/autocreate sync Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 10/15] libbpf: replace elf_state->st_ops_* fields with SEC_ST_OPS sec_type Eduard Zingerman
2024-03-02  1:19 ` Eduard Zingerman [this message]
2024-03-02  1:19 ` [PATCH bpf-next v2 12/15] libbpf: rewrite btf datasec names starting from '?' Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 13/15] selftests/bpf: test case for SEC("?.struct_ops") Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 14/15] bpf: allow '?' at the beginning of DATASEC names Eduard Zingerman
2024-03-02  1:19 ` [PATCH bpf-next v2 15/15] selftests/bpf: test cases for '?' in BTF names Eduard Zingerman

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