1 files changed, 133 insertions, 37 deletions

diff --git a/include/linux/btf.h b/include/linux/btf.h
index 0c74348cbc9d..f9aababc5d78 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -12,11 +12,73 @@
 #define BTF_TYPE_EMIT(type) ((void)(type *)0)
 #define BTF_TYPE_EMIT_ENUM(enum_val) ((void)enum_val)
 
+/* 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 */
+/* Trusted arguments are those which are meant to be referenced arguments with
+ * unchanged offset. It is used to enforce that pointers obtained from acquire
+ * kfuncs remain unmodified when being passed to helpers taking trusted args.
+ *
+ * Consider
+ *	struct foo {
+ *		int data;
+ *		struct foo *next;
+ *	};
+ *
+ *	struct bar {
+ *		int data;
+ *		struct foo f;
+ *	};
+ *
+ *	struct foo *f = alloc_foo(); // Acquire kfunc
+ *	struct bar *b = alloc_bar(); // Acquire kfunc
+ *
+ * If a kfunc set_foo_data() wants to operate only on the allocated object, it
+ * will set the KF_TRUSTED_ARGS flag, which will prevent unsafe usage like:
+ *
+ *	set_foo_data(f, 42);	   // Allowed
+ *	set_foo_data(f->next, 42); // Rejected, non-referenced pointer
+ *	set_foo_data(&f->next, 42);// Rejected, referenced, but wrong type
+ *	set_foo_data(&b->f, 42);   // Rejected, referenced, but bad offset
+ *
+ * In the final case, usually for the purposes of type matching, it is deduced
+ * by looking at the type of the member at the offset, but due to the
+ * requirement of trusted argument, this deduction will be strict and not done
+ * for this case.
+ */
+#define KF_TRUSTED_ARGS (1 << 4) /* kfunc only takes trusted pointer arguments */
+#define KF_SLEEPABLE    (1 << 5) /* kfunc may sleep */
+#define KF_DESTRUCTIVE  (1 << 6) /* kfunc performs destructive actions */
+
+/*
+ * Return the name of the passed struct, if exists, or halt the build if for
+ * example the structure gets renamed. In this way, developers have to revisit
+ * the code using that structure name, and update it accordingly.
+ */
+#define stringify_struct(x)			\
+	({ BUILD_BUG_ON(sizeof(struct x) < 0);	\
+	   __stringify(x); })
+
 struct btf;
 struct btf_member;
 struct btf_type;
 union bpf_attr;
 struct btf_show;
+struct btf_id_set;
+
+struct btf_kfunc_id_set {
+	struct module *owner;
+	struct btf_id_set8 *set;
+};
+
+struct btf_id_dtor_kfunc {
+	u32 btf_id;
+	u32 kfunc_btf_id;
+};
+
+typedef void (*btf_dtor_kfunc_t)(void *);
 
 extern const struct file_operations btf_fops;
 
@@ -101,6 +163,8 @@ bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
 			   u32 expected_offset, u32 expected_size);
 int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t);
 int btf_find_timer(const struct btf *btf, const struct btf_type *t);
+struct bpf_map_value_off *btf_parse_kptrs(const struct btf *btf,
+					  const struct btf_type *t);
 bool btf_type_is_void(const struct btf_type *t);
 s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind);
 const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
@@ -144,6 +208,19 @@ static inline bool btf_type_is_enum(const struct btf_type *t)
 	return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM;
 }
 
+static inline bool btf_is_any_enum(const struct btf_type *t)
+{
+	return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM ||
+	       BTF_INFO_KIND(t->info) == BTF_KIND_ENUM64;
+}
+
+static inline bool btf_kind_core_compat(const struct btf_type *t1,
+					const struct btf_type *t2)
+{
+	return BTF_INFO_KIND(t1->info) == BTF_INFO_KIND(t2->info) ||
+	       (btf_is_any_enum(t1) && btf_is_any_enum(t2));
+}
+
 static inline bool str_is_empty(const char *s)
 {
 	return !s || !s[0];
@@ -159,6 +236,16 @@ static inline bool btf_is_enum(const struct btf_type *t)
 	return btf_kind(t) == BTF_KIND_ENUM;
 }
 
+static inline bool btf_is_enum64(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_ENUM64;
+}
+
+static inline u64 btf_enum64_value(const struct btf_enum64 *e)
+{
+	return ((u64)e->val_hi32 << 32) | e->val_lo32;
+}
+
 static inline bool btf_is_composite(const struct btf_type *t)
 {
 	u16 kind = btf_kind(t);
@@ -216,6 +303,11 @@ static inline bool btf_type_is_var(const struct btf_type *t)
 	return BTF_INFO_KIND(t->info) == BTF_KIND_VAR;
 }
 
+static inline bool btf_type_is_type_tag(const struct btf_type *t)
+{
+	return BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG;
+}
+
 /* union is only a special case of struct:
  * all its offsetof(member) == 0
  */
@@ -294,12 +386,22 @@ static inline struct btf_enum *btf_enum(const struct btf_type *t)
 	return (struct btf_enum *)(t + 1);
 }
 
+static inline struct btf_enum64 *btf_enum64(const struct btf_type *t)
+{
+	return (struct btf_enum64 *)(t + 1);
+}
+
 static inline const struct btf_var_secinfo *btf_type_var_secinfo(
 		const struct btf_type *t)
 {
 	return (const struct btf_var_secinfo *)(t + 1);
 }
 
+static inline struct btf_param *btf_params(const struct btf_type *t)
+{
+	return (struct btf_param *)(t + 1);
+}
+
 #ifdef CONFIG_BPF_SYSCALL
 struct bpf_prog;
 
@@ -307,6 +409,14 @@ 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);
+u32 *btf_kfunc_id_set_contains(const struct btf *btf,
+			       enum bpf_prog_type prog_type,
+			       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);
+int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
+				struct module *owner);
 #else
 static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
 						    u32 type_id)
@@ -318,50 +428,36 @@ static inline const char *btf_name_by_offset(const struct btf *btf,
 {
 	return NULL;
 }
-#endif
-
-struct kfunc_btf_id_set {
-	struct list_head list;
-	struct btf_id_set *set;
-	struct module *owner;
-};
-
-struct kfunc_btf_id_list {
-	struct list_head list;
-	struct mutex mutex;
-};
-
-#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
-void register_kfunc_btf_id_set(struct kfunc_btf_id_list *l,
-			       struct kfunc_btf_id_set *s);
-void unregister_kfunc_btf_id_set(struct kfunc_btf_id_list *l,
-				 struct kfunc_btf_id_set *s);
-bool bpf_check_mod_kfunc_call(struct kfunc_btf_id_list *klist, u32 kfunc_id,
-			      struct module *owner);
-
-extern struct kfunc_btf_id_list bpf_tcp_ca_kfunc_list;
-extern struct kfunc_btf_id_list prog_test_kfunc_list;
-#else
-static inline void register_kfunc_btf_id_set(struct kfunc_btf_id_list *l,
-					     struct kfunc_btf_id_set *s)
+static inline u32 *btf_kfunc_id_set_contains(const struct btf *btf,
+					     enum bpf_prog_type prog_type,
+					     u32 kfunc_btf_id)
 {
+	return NULL;
 }
-static inline void unregister_kfunc_btf_id_set(struct kfunc_btf_id_list *l,
-					       struct kfunc_btf_id_set *s)
+static inline int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
+					    const struct btf_kfunc_id_set *s)
 {
+	return 0;
 }
-static inline bool bpf_check_mod_kfunc_call(struct kfunc_btf_id_list *klist,
-					    u32 kfunc_id, struct module *owner)
+static inline s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
 {
-	return false;
+	return -ENOENT;
+}
+static inline int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors,
+					      u32 add_cnt, struct module *owner)
+{
+	return 0;
 }
-
-static struct kfunc_btf_id_list bpf_tcp_ca_kfunc_list __maybe_unused;
-static struct kfunc_btf_id_list prog_test_kfunc_list __maybe_unused;
 #endif
 
-#define DEFINE_KFUNC_BTF_ID_SET(set, name)                                     \
-	struct kfunc_btf_id_set name = { LIST_HEAD_INIT(name.list), (set),     \
-					 THIS_MODULE }
+static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t)
+{
+	if (!btf_type_is_ptr(t))
+		return false;
+
+	t = btf_type_skip_modifiers(btf, t->type, NULL);
+
+	return btf_type_is_struct(t);
+}
 
 #endif