bpf: Switch to new kfunc flags infrastructure

Instead of populating multiple sets to indicate some attribute and then
researching the same BTF ID in them, prepare a single unified BTF set
which indicates whether a kfunc is allowed to be called, and also its
attributes if any at the same time. Now, only one call is needed to
perform the lookup for both kfunc availability and its attributes.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

2 files changed, 12 insertions, 24 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 11950029284f..a97751d845c9 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1924,7 +1924,8 @@ int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
 				struct bpf_reg_state *regs);
 int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
 			      const struct btf *btf, u32 func_id,
-			      struct bpf_reg_state *regs);
+			      struct bpf_reg_state *regs,
+			      u32 kfunc_flags);
 int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
 			  struct bpf_reg_state *reg);
 int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
diff --git a/include/linux/btf.h b/include/linux/btf.h
index 1bfed7fa0428..6dfc6eaf7f8c 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -12,14 +12,11 @@
 #define BTF_TYPE_EMIT(type) ((void)(type *)0)
 #define BTF_TYPE_EMIT_ENUM(enum_val) ((void)enum_val)
 
-enum btf_kfunc_type {
-	BTF_KFUNC_TYPE_CHECK,
-	BTF_KFUNC_TYPE_ACQUIRE,
-	BTF_KFUNC_TYPE_RELEASE,
-	BTF_KFUNC_TYPE_RET_NULL,
-	BTF_KFUNC_TYPE_KPTR_ACQUIRE,
-	BTF_KFUNC_TYPE_MAX,
-};
+/* These need to be macros, as the expressions are used in assembler input */
+#define KF_ACQUIRE	(1 << 0) /* kfunc is an acquire function */
+#define KF_RELEASE	(1 << 1) /* kfunc is a release function */
+#define KF_RET_NULL	(1 << 2) /* kfunc returns a pointer that may be NULL */
+#define KF_KPTR_GET	(1 << 3) /* kfunc returns reference to a kptr */
 
 struct btf;
 struct btf_member;
@@ -30,16 +27,7 @@ struct btf_id_set;
 
 struct btf_kfunc_id_set {
 	struct module *owner;
-	union {
-		struct {
-			struct btf_id_set *check_set;
-			struct btf_id_set *acquire_set;
-			struct btf_id_set *release_set;
-			struct btf_id_set *ret_null_set;
-			struct btf_id_set *kptr_acquire_set;
-		};
-		struct btf_id_set *sets[BTF_KFUNC_TYPE_MAX];
-	};
+	struct btf_id_set8 *set;
 };
 
 struct btf_id_dtor_kfunc {
@@ -378,9 +366,9 @@ const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
 const char *btf_name_by_offset(const struct btf *btf, u32 offset);
 struct btf *btf_parse_vmlinux(void);
 struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog);
-bool btf_kfunc_id_set_contains(const struct btf *btf,
+u32 *btf_kfunc_id_set_contains(const struct btf *btf,
 			       enum bpf_prog_type prog_type,
-			       enum btf_kfunc_type type, u32 kfunc_btf_id);
+			       u32 kfunc_btf_id);
 int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
 			      const struct btf_kfunc_id_set *s);
 s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id);
@@ -397,12 +385,11 @@ static inline const char *btf_name_by_offset(const struct btf *btf,
 {
 	return NULL;
 }
-static inline bool btf_kfunc_id_set_contains(const struct btf *btf,
+static inline u32 *btf_kfunc_id_set_contains(const struct btf *btf,
 					     enum bpf_prog_type prog_type,
-					     enum btf_kfunc_type type,
 					     u32 kfunc_btf_id)
 {
-	return false;
+	return NULL;
 }
 static inline int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
 					    const struct btf_kfunc_id_set *s)