[RFC PATCH bpf-next 1/7] bpf: Add capability field to BTF_ID_FLAGS

[Juntong Deng]

This patch adds capability field to BTF_ID_FLAGS to record capability
information of each kfunc.

Note that the capability field is just a placeholder, the actual
capability value is set in btf_populate_kfunc_set_cap.

Signed-off-by: Juntong Deng <juntong.deng@xxxxxxxxxxx>
---
 include/linux/btf_ids.h         | 6 +++++-
 tools/bpf/resolve_btfids/main.c | 2 +-
 tools/include/linux/btf_ids.h   | 1 +
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 139bdececdcf..40231ea36058 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -19,6 +19,7 @@ struct btf_id_set8 {
 	struct {
 		u32 id;
 		u32 flags;
+		u32 capability;
 	} pairs[];
 };
 
@@ -65,7 +66,10 @@ word							\
 	__BTF_ID(__ID(__BTF_ID__##prefix##__##name##__), "")
 
 #define ____BTF_ID_FLAGS(prefix, name, flags) \
-	__BTF_ID(__ID(__BTF_ID__##prefix##__##name##__), ".long " #flags "\n")
+	__BTF_ID(__ID(__BTF_ID__##prefix##__##name##__), \
+	".long " #flags "\n"				 \
+	".zero 4         \n")
+
 #define __BTF_ID_FLAGS(prefix, name, flags, ...) \
 	____BTF_ID_FLAGS(prefix, name, flags)
 #define BTF_ID_FLAGS(prefix, name, ...) \
diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index d47191c6e55e..48be22f9a14e 100644
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -495,7 +495,7 @@ static int symbols_collect(struct object *obj)
 			 * that - 1.
 			 */
 			if (id) {
-				id->cnt = sym.st_size / sizeof(uint64_t) - 1;
+				id->cnt = (sym.st_size - sizeof(u32) * 2) / (sizeof(u32) * 3);
 				id->is_set8 = true;
 			}
 		/* set */
diff --git a/tools/include/linux/btf_ids.h b/tools/include/linux/btf_ids.h
index 72ea363d434d..a6c9b560b6ce 100644
--- a/tools/include/linux/btf_ids.h
+++ b/tools/include/linux/btf_ids.h
@@ -16,6 +16,7 @@ struct btf_id_set8 {
 	struct {
 		u32 id;
 		u32 flags;
+		u32 capability;
 	} pairs[];
 };
 
-- 
2.39.5