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authorEduard Zingerman <eddyz87@gmail.com>2024-03-06 12:45:22 +0200
committerAndrii Nakryiko <andrii@kernel.org>2024-03-06 15:18:15 -0800
commitfe9d049c3da06373a1a35914b7f695509e4cb1fe (patch)
tree6c12581c804da865f4d0f7bf2b224e1d0543f90a /tools/lib
parent1863acccdf936c6917398165ca97e252d02fa6dd (diff)
libbpf: Sync progs autoload with maps autocreate for struct_ops maps
Automatically select which struct_ops programs to load depending on which struct_ops maps are selected for automatic creation. E.g. for the BPF code below: SEC("struct_ops/test_1") int BPF_PROG(foo) { ... } SEC("struct_ops/test_2") int BPF_PROG(bar) { ... } SEC(".struct_ops.link") struct test_ops___v1 A = { .foo = (void *)foo }; SEC(".struct_ops.link") struct test_ops___v2 B = { .foo = (void *)foo, .bar = (void *)bar, }; And the following libbpf API calls: bpf_map__set_autocreate(skel->maps.A, true); bpf_map__set_autocreate(skel->maps.B, false); The autoload would be enabled for program 'foo' and disabled for program 'bar'. During load, for each struct_ops program P, referenced from some struct_ops map M: - set P.autoload = true if M.autocreate is true for some M; - set P.autoload = false if M.autocreate is false for all M; - don't change P.autoload, if P is not referenced from any map. Do this after bpf_object__init_kern_struct_ops_maps() to make sure that shadow vars assignment is done. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240306104529.6453-9-eddyz87@gmail.com
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/bpf/libbpf.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 1fb9a4f237b4..595c287d84ef 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1031,6 +1031,48 @@ static bool is_valid_st_ops_program(struct bpf_object *obj,
return false;
}
+/* For each struct_ops program P, referenced from some struct_ops map M,
+ * enable P.autoload if there are Ms for which M.autocreate is true,
+ * disable P.autoload if for all Ms M.autocreate is false.
+ * Don't change P.autoload for programs that are not referenced from any maps.
+ */
+static int bpf_object_adjust_struct_ops_autoload(struct bpf_object *obj)
+{
+ struct bpf_program *prog, *slot_prog;
+ struct bpf_map *map;
+ int i, j, k, vlen;
+
+ for (i = 0; i < obj->nr_programs; ++i) {
+ int should_load = false;
+ int use_cnt = 0;
+
+ prog = &obj->programs[i];
+ if (prog->type != BPF_PROG_TYPE_STRUCT_OPS)
+ continue;
+
+ for (j = 0; j < obj->nr_maps; ++j) {
+ map = &obj->maps[j];
+ if (!bpf_map__is_struct_ops(map))
+ continue;
+
+ vlen = btf_vlen(map->st_ops->type);
+ for (k = 0; k < vlen; ++k) {
+ slot_prog = map->st_ops->progs[k];
+ if (prog != slot_prog)
+ continue;
+
+ use_cnt++;
+ if (map->autocreate)
+ should_load = true;
+ }
+ }
+ if (use_cnt)
+ prog->autoload = should_load;
+ }
+
+ return 0;
+}
+
/* Init the map's fields that depend on kern_btf */
static int bpf_map__init_kern_struct_ops(struct bpf_map *map)
{
@@ -8175,6 +8217,7 @@ static int bpf_object_load(struct bpf_object *obj, int extra_log_level, const ch
err = err ? : bpf_object__resolve_externs(obj, obj->kconfig);
err = err ? : bpf_object__sanitize_maps(obj);
err = err ? : bpf_object__init_kern_struct_ops_maps(obj);
+ err = err ? : bpf_object_adjust_struct_ops_autoload(obj);
err = err ? : bpf_object__relocate(obj, obj->btf_custom_path ? : target_btf_path);
err = err ? : bpf_object__sanitize_and_load_btf(obj);
err = err ? : bpf_object__create_maps(obj);