Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso...

[linux-2.6-microblaze.git] / include / linux / btf.h

diff --git a/include/linux/btf.h b/include/linux/btf.h
index 1bfed7f..cdb376d 100644 (file)
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -12,14 +12,43 @@
 #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 */
+/* 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 */
 
 struct btf;
 struct btf_member;
@@ -30,16 +59,7 @@ 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 +398,9 @@ 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 +417,11 @@ 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)