bpf: Support struct btf_struct_meta via KF_IMPLICIT_ARGS

The following kfuncs currently accept void *meta__ign argument:
  * bpf_obj_new_impl
  * bpf_obj_drop_impl
  * bpf_percpu_obj_new_impl
  * bpf_percpu_obj_drop_impl
  * bpf_refcount_acquire_impl
  * bpf_list_push_back_impl
  * bpf_list_push_front_impl
  * bpf_rbtree_add_impl

The __ign suffix is an indicator for the verifier to skip the argument
in check_kfunc_args(). Then, in fixup_kfunc_call() the verifier may
set the value of this argument to struct btf_struct_meta *
kptr_struct_meta from insn_aux_data.

BPF programs must pass a dummy NULL value when calling these kfuncs.

Additionally, the list and rbtree _impl kfuncs also accept an implicit
u64 argument, which doesn't require __ign suffix because it's a
scalar, and BPF programs explicitly pass 0.

Add new kfuncs with KF_IMPLICIT_ARGS [1], that correspond to each
_impl kfunc accepting meta__ign. The existing _impl kfuncs remain
unchanged for backwards compatibility.

To support this, add "btf_struct_meta" to the list of recognized
implicit argument types in resolve_btfids.

Implement is_kfunc_arg_implicit() in the verifier, that determines
implicit args by inspecting both a non-_impl BTF prototype of the
kfunc.

Update the special_kfunc_list in the verifier and relevant checks to
support both the old _impl and the new KF_IMPLICIT_ARGS variants of
btf_struct_meta users.

[1] https://lore.kernel.org/bpf/20260120222638.3976562-1-ihor.solodrai@linux.dev/

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260327203241.3365046-1-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 139bdececdcfaefbb5c34985683f6192a2718b69..af011db39ab3f62363e829b7756799176dbad55d 100644 (file)
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -217,7 +217,7 @@ BTF_SET8_END(name)
 
 #else
 
-#define BTF_ID_LIST(name) static u32 __maybe_unused name[64];
+#define BTF_ID_LIST(name) static u32 __maybe_unused name[128];
 #define BTF_ID(prefix, name)
 #define BTF_ID_FLAGS(prefix, name, ...)
 #define BTF_ID_UNUSED

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index cb6d242bd0936969cc65c951d4215d39a16aabda..2d8538bf4cfaa19bfa6488b30f8cdd0c4b2e68ad 100644 (file)
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2302,9 +2302,20 @@ void bpf_rb_root_free(const struct btf_field *field, void *rb_root,
 
 __bpf_kfunc_start_defs();
 
-__bpf_kfunc void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign)
+/**
+ * bpf_obj_new() - allocate an object described by program BTF
+ * @local_type_id__k: type ID in program BTF
+ * @meta: verifier-supplied struct metadata
+ *
+ * Allocate an object of the type identified by @local_type_id__k and
+ * initialize its special fields. BPF programs can use
+ * bpf_core_type_id_local() to provide @local_type_id__k. The verifier
+ * rewrites @meta; BPF programs do not set it.
+ *
+ * Return: Pointer to the allocated object, or %NULL on failure.
+ */
+__bpf_kfunc void *bpf_obj_new(u64 local_type_id__k, struct btf_struct_meta *meta)
 {
-       struct btf_struct_meta *meta = meta__ign;
        u64 size = local_type_id__k;
        void *p;
 
@@ -2313,17 +2324,39 @@ __bpf_kfunc void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign)
                return NULL;
        if (meta)
                bpf_obj_init(meta->record, p);
+
        return p;
 }
 
-__bpf_kfunc void *bpf_percpu_obj_new_impl(u64 local_type_id__k, void *meta__ign)
+__bpf_kfunc void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign)
+{
+       return bpf_obj_new(local_type_id__k, meta__ign);
+}
+
+/**
+ * bpf_percpu_obj_new() - allocate a percpu object described by program BTF
+ * @local_type_id__k: type ID in program BTF
+ * @meta: verifier-supplied struct metadata
+ *
+ * Allocate a percpu object of the type identified by @local_type_id__k. BPF
+ * programs can use bpf_core_type_id_local() to provide @local_type_id__k.
+ * The verifier rewrites @meta; BPF programs do not set it.
+ *
+ * Return: Pointer to the allocated percpu object, or %NULL on failure.
+ */
+__bpf_kfunc void *bpf_percpu_obj_new(u64 local_type_id__k, struct btf_struct_meta *meta)
 {
        u64 size = local_type_id__k;
 
-       /* The verifier has ensured that meta__ign must be NULL */
+       /* The verifier has ensured that meta must be NULL */
        return bpf_mem_alloc(&bpf_global_percpu_ma, size);
 }
 
+__bpf_kfunc void *bpf_percpu_obj_new_impl(u64 local_type_id__k, void *meta__ign)
+{
+       return bpf_percpu_obj_new(local_type_id__k, meta__ign);
+}
+
 /* Must be called under migrate_disable(), as required by bpf_mem_free */
 void __bpf_obj_drop_impl(void *p, const struct btf_record *rec, bool percpu)
 {
@@ -2347,23 +2380,56 @@ void __bpf_obj_drop_impl(void *p, const struct btf_record *rec, bool percpu)
        bpf_mem_free_rcu(ma, p);
 }
 
-__bpf_kfunc void bpf_obj_drop_impl(void *p__alloc, void *meta__ign)
+/**
+ * bpf_obj_drop() - drop a previously allocated object
+ * @p__alloc: object to free
+ * @meta: verifier-supplied struct metadata
+ *
+ * Destroy special fields in @p__alloc as needed and free the object. The
+ * verifier rewrites @meta; BPF programs do not set it.
+ */
+__bpf_kfunc void bpf_obj_drop(void *p__alloc, struct btf_struct_meta *meta)
 {
-       struct btf_struct_meta *meta = meta__ign;
        void *p = p__alloc;
 
        __bpf_obj_drop_impl(p, meta ? meta->record : NULL, false);
 }
 
-__bpf_kfunc void bpf_percpu_obj_drop_impl(void *p__alloc, void *meta__ign)
+__bpf_kfunc void bpf_obj_drop_impl(void *p__alloc, void *meta__ign)
+{
+       return bpf_obj_drop(p__alloc, meta__ign);
+}
+
+/**
+ * bpf_percpu_obj_drop() - drop a previously allocated percpu object
+ * @p__alloc: percpu object to free
+ * @meta: verifier-supplied struct metadata
+ *
+ * Free @p__alloc. The verifier rewrites @meta; BPF programs do not set it.
+ */
+__bpf_kfunc void bpf_percpu_obj_drop(void *p__alloc, struct btf_struct_meta *meta)
 {
-       /* The verifier has ensured that meta__ign must be NULL */
+       /* The verifier has ensured that meta must be NULL */
        bpf_mem_free_rcu(&bpf_global_percpu_ma, p__alloc);
 }
 
-__bpf_kfunc void *bpf_refcount_acquire_impl(void *p__refcounted_kptr, void *meta__ign)
+__bpf_kfunc void bpf_percpu_obj_drop_impl(void *p__alloc, void *meta__ign)
+{
+       bpf_percpu_obj_drop(p__alloc, meta__ign);
+}
+
+/**
+ * bpf_refcount_acquire() - turn a local kptr into an owning reference
+ * @p__refcounted_kptr: non-owning local kptr
+ * @meta: verifier-supplied struct metadata
+ *
+ * Increment the refcount for @p__refcounted_kptr. The verifier rewrites
+ * @meta; BPF programs do not set it.
+ *
+ * Return: Owning reference to @p__refcounted_kptr, or %NULL on failure.
+ */
+__bpf_kfunc void *bpf_refcount_acquire(void *p__refcounted_kptr, struct btf_struct_meta *meta)
 {
-       struct btf_struct_meta *meta = meta__ign;
        struct bpf_refcount *ref;
 
        /* Could just cast directly to refcount_t *, but need some code using
@@ -2379,6 +2445,11 @@ __bpf_kfunc void *bpf_refcount_acquire_impl(void *p__refcounted_kptr, void *meta
        return (void *)p__refcounted_kptr;
 }
 
+__bpf_kfunc void *bpf_refcount_acquire_impl(void *p__refcounted_kptr, void *meta__ign)
+{
+       return bpf_refcount_acquire(p__refcounted_kptr, meta__ign);
+}
+
 static int __bpf_list_add(struct bpf_list_node_kern *node,
                          struct bpf_list_head *head,
                          bool tail, struct btf_record *rec, u64 off)
@@ -2406,24 +2477,62 @@ static int __bpf_list_add(struct bpf_list_node_kern *node,
        return 0;
 }
 
+/**
+ * bpf_list_push_front() - add a node to the front of a BPF linked list
+ * @head: list head
+ * @node: node to insert
+ * @meta: verifier-supplied struct metadata
+ * @off: verifier-supplied offset of @node within the containing object
+ *
+ * Insert @node at the front of @head. The verifier rewrites @meta and @off;
+ * BPF programs do not set them.
+ *
+ * Return: 0 on success, or %-EINVAL if @node is already linked.
+ */
+__bpf_kfunc int bpf_list_push_front(struct bpf_list_head *head,
+                                   struct bpf_list_node *node,
+                                   struct btf_struct_meta *meta,
+                                   u64 off)
+{
+       struct bpf_list_node_kern *n = (void *)node;
+
+       return __bpf_list_add(n, head, false, meta ? meta->record : NULL, off);
+}
+
 __bpf_kfunc int bpf_list_push_front_impl(struct bpf_list_head *head,
                                         struct bpf_list_node *node,
                                         void *meta__ign, u64 off)
+{
+       return bpf_list_push_front(head, node, meta__ign, off);
+}
+
+/**
+ * bpf_list_push_back() - add a node to the back of a BPF linked list
+ * @head: list head
+ * @node: node to insert
+ * @meta: verifier-supplied struct metadata
+ * @off: verifier-supplied offset of @node within the containing object
+ *
+ * Insert @node at the back of @head. The verifier rewrites @meta and @off;
+ * BPF programs do not set them.
+ *
+ * Return: 0 on success, or %-EINVAL if @node is already linked.
+ */
+__bpf_kfunc int bpf_list_push_back(struct bpf_list_head *head,
+                                  struct bpf_list_node *node,
+                                  struct btf_struct_meta *meta,
+                                  u64 off)
 {
        struct bpf_list_node_kern *n = (void *)node;
-       struct btf_struct_meta *meta = meta__ign;
 
-       return __bpf_list_add(n, head, false, meta ? meta->record : NULL, off);
+       return __bpf_list_add(n, head, true, meta ? meta->record : NULL, off);
 }
 
 __bpf_kfunc int bpf_list_push_back_impl(struct bpf_list_head *head,
                                        struct bpf_list_node *node,
                                        void *meta__ign, u64 off)
 {
-       struct bpf_list_node_kern *n = (void *)node;
-       struct btf_struct_meta *meta = meta__ign;
-
-       return __bpf_list_add(n, head, true, meta ? meta->record : NULL, off);
+       return bpf_list_push_back(head, node, meta__ign, off);
 }
 
 static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tail)
@@ -2535,16 +2644,37 @@ static int __bpf_rbtree_add(struct bpf_rb_root *root,
        return 0;
 }
 
-__bpf_kfunc int bpf_rbtree_add_impl(struct bpf_rb_root *root, struct bpf_rb_node *node,
-                                   bool (less)(struct bpf_rb_node *a, const struct bpf_rb_node *b),
-                                   void *meta__ign, u64 off)
+/**
+ * bpf_rbtree_add() - add a node to a BPF rbtree
+ * @root: tree root
+ * @node: node to insert
+ * @less: comparator used to order nodes
+ * @meta: verifier-supplied struct metadata
+ * @off: verifier-supplied offset of @node within the containing object
+ *
+ * Insert @node into @root using @less. The verifier rewrites @meta and @off;
+ * BPF programs do not set them.
+ *
+ * Return: 0 on success, or %-EINVAL if @node is already linked in a tree.
+ */
+__bpf_kfunc int bpf_rbtree_add(struct bpf_rb_root *root,
+                              struct bpf_rb_node *node,
+                              bool (less)(struct bpf_rb_node *a, const struct bpf_rb_node *b),
+                              struct btf_struct_meta *meta,
+                              u64 off)
 {
-       struct btf_struct_meta *meta = meta__ign;
        struct bpf_rb_node_kern *n = (void *)node;
 
        return __bpf_rbtree_add(root, n, (void *)less, meta ? meta->record : NULL, off);
 }
 
+__bpf_kfunc int bpf_rbtree_add_impl(struct bpf_rb_root *root, struct bpf_rb_node *node,
+                                   bool (less)(struct bpf_rb_node *a, const struct bpf_rb_node *b),
+                                   void *meta__ign, u64 off)
+{
+       return bpf_rbtree_add(root, node, less, meta__ign, off);
+}
+
 __bpf_kfunc struct bpf_rb_node *bpf_rbtree_first(struct bpf_rb_root *root)
 {
        struct rb_root_cached *r = (struct rb_root_cached *)root;
@@ -4536,12 +4666,19 @@ BTF_KFUNCS_START(generic_btf_ids)
 #ifdef CONFIG_CRASH_DUMP
 BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE)
 #endif
+BTF_ID_FLAGS(func, bpf_obj_new, KF_ACQUIRE | KF_RET_NULL | KF_IMPLICIT_ARGS)
 BTF_ID_FLAGS(func, bpf_obj_new_impl, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_percpu_obj_new, KF_ACQUIRE | KF_RET_NULL | KF_IMPLICIT_ARGS)
 BTF_ID_FLAGS(func, bpf_percpu_obj_new_impl, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_obj_drop, KF_RELEASE | KF_IMPLICIT_ARGS)
 BTF_ID_FLAGS(func, bpf_obj_drop_impl, KF_RELEASE)
+BTF_ID_FLAGS(func, bpf_percpu_obj_drop, KF_RELEASE | KF_IMPLICIT_ARGS)
 BTF_ID_FLAGS(func, bpf_percpu_obj_drop_impl, KF_RELEASE)
+BTF_ID_FLAGS(func, bpf_refcount_acquire, KF_ACQUIRE | KF_RET_NULL | KF_RCU | KF_IMPLICIT_ARGS)
 BTF_ID_FLAGS(func, bpf_refcount_acquire_impl, KF_ACQUIRE | KF_RET_NULL | KF_RCU)
+BTF_ID_FLAGS(func, bpf_list_push_front, KF_IMPLICIT_ARGS)
 BTF_ID_FLAGS(func, bpf_list_push_front_impl)
+BTF_ID_FLAGS(func, bpf_list_push_back, KF_IMPLICIT_ARGS)
 BTF_ID_FLAGS(func, bpf_list_push_back_impl)
 BTF_ID_FLAGS(func, bpf_list_pop_front, KF_ACQUIRE | KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL)
@@ -4550,6 +4687,7 @@ BTF_ID_FLAGS(func, bpf_list_back, KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_task_release, KF_RELEASE)
 BTF_ID_FLAGS(func, bpf_rbtree_remove, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_rbtree_add, KF_IMPLICIT_ARGS)
 BTF_ID_FLAGS(func, bpf_rbtree_add_impl)
 BTF_ID_FLAGS(func, bpf_rbtree_first, KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_rbtree_root, KF_RET_NULL)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 11207e63c94eac52f07ab02f9a63569ecc618029..8c1cf2eb6cbbdd38a79014d903f880a94b526504 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -12473,6 +12473,28 @@ static bool is_kfunc_arg_prog_aux(const struct btf *btf, const struct btf_param
        return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_PROG_AUX_ID);
 }
 
+/*
+ * A kfunc with KF_IMPLICIT_ARGS has two prototypes in BTF:
+ *   - the _impl prototype with full arg list (meta->func_proto)
+ *   - the BPF API prototype w/o implicit args (func->type in BTF)
+ * To determine whether an argument is implicit, we compare its position
+ * against the number of arguments in the prototype w/o implicit args.
+ */
+static bool is_kfunc_arg_implicit(const struct bpf_kfunc_call_arg_meta *meta, u32 arg_idx)
+{
+       const struct btf_type *func, *func_proto;
+       u32 argn;
+
+       if (!(meta->kfunc_flags & KF_IMPLICIT_ARGS))
+               return false;
+
+       func = btf_type_by_id(meta->btf, meta->func_id);
+       func_proto = btf_type_by_id(meta->btf, func->type);
+       argn = btf_type_vlen(func_proto);
+
+       return argn <= arg_idx;
+}
+
 /* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
 static bool __btf_type_is_scalar_struct(struct bpf_verifier_env *env,
                                        const struct btf *btf,
@@ -12539,10 +12561,15 @@ enum kfunc_ptr_arg_type {
 
 enum special_kfunc_type {
        KF_bpf_obj_new_impl,
+       KF_bpf_obj_new,
        KF_bpf_obj_drop_impl,
+       KF_bpf_obj_drop,
        KF_bpf_refcount_acquire_impl,
+       KF_bpf_refcount_acquire,
        KF_bpf_list_push_front_impl,
+       KF_bpf_list_push_front,
        KF_bpf_list_push_back_impl,
+       KF_bpf_list_push_back,
        KF_bpf_list_pop_front,
        KF_bpf_list_pop_back,
        KF_bpf_list_front,
@@ -12553,6 +12580,7 @@ enum special_kfunc_type {
        KF_bpf_rcu_read_unlock,
        KF_bpf_rbtree_remove,
        KF_bpf_rbtree_add_impl,
+       KF_bpf_rbtree_add,
        KF_bpf_rbtree_first,
        KF_bpf_rbtree_root,
        KF_bpf_rbtree_left,
@@ -12565,7 +12593,9 @@ enum special_kfunc_type {
        KF_bpf_dynptr_slice_rdwr,
        KF_bpf_dynptr_clone,
        KF_bpf_percpu_obj_new_impl,
+       KF_bpf_percpu_obj_new,
        KF_bpf_percpu_obj_drop_impl,
+       KF_bpf_percpu_obj_drop,
        KF_bpf_throw,
        KF_bpf_wq_set_callback,
        KF_bpf_preempt_disable,
@@ -12599,10 +12629,15 @@ enum special_kfunc_type {
 
 BTF_ID_LIST(special_kfunc_list)
 BTF_ID(func, bpf_obj_new_impl)
+BTF_ID(func, bpf_obj_new)
 BTF_ID(func, bpf_obj_drop_impl)
+BTF_ID(func, bpf_obj_drop)
 BTF_ID(func, bpf_refcount_acquire_impl)
+BTF_ID(func, bpf_refcount_acquire)
 BTF_ID(func, bpf_list_push_front_impl)
+BTF_ID(func, bpf_list_push_front)
 BTF_ID(func, bpf_list_push_back_impl)
+BTF_ID(func, bpf_list_push_back)
 BTF_ID(func, bpf_list_pop_front)
 BTF_ID(func, bpf_list_pop_back)
 BTF_ID(func, bpf_list_front)
@@ -12613,6 +12648,7 @@ BTF_ID(func, bpf_rcu_read_lock)
 BTF_ID(func, bpf_rcu_read_unlock)
 BTF_ID(func, bpf_rbtree_remove)
 BTF_ID(func, bpf_rbtree_add_impl)
+BTF_ID(func, bpf_rbtree_add)
 BTF_ID(func, bpf_rbtree_first)
 BTF_ID(func, bpf_rbtree_root)
 BTF_ID(func, bpf_rbtree_left)
@@ -12632,7 +12668,9 @@ BTF_ID(func, bpf_dynptr_slice)
 BTF_ID(func, bpf_dynptr_slice_rdwr)
 BTF_ID(func, bpf_dynptr_clone)
 BTF_ID(func, bpf_percpu_obj_new_impl)
+BTF_ID(func, bpf_percpu_obj_new)
 BTF_ID(func, bpf_percpu_obj_drop_impl)
+BTF_ID(func, bpf_percpu_obj_drop)
 BTF_ID(func, bpf_throw)
 BTF_ID(func, bpf_wq_set_callback)
 BTF_ID(func, bpf_preempt_disable)
@@ -12676,6 +12714,50 @@ BTF_ID(func, bpf_session_is_return)
 BTF_ID(func, bpf_stream_vprintk)
 BTF_ID(func, bpf_stream_print_stack)
 
+static bool is_bpf_obj_new_kfunc(u32 func_id)
+{
+       return func_id == special_kfunc_list[KF_bpf_obj_new] ||
+              func_id == special_kfunc_list[KF_bpf_obj_new_impl];
+}
+
+static bool is_bpf_percpu_obj_new_kfunc(u32 func_id)
+{
+       return func_id == special_kfunc_list[KF_bpf_percpu_obj_new] ||
+              func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl];
+}
+
+static bool is_bpf_obj_drop_kfunc(u32 func_id)
+{
+       return func_id == special_kfunc_list[KF_bpf_obj_drop] ||
+              func_id == special_kfunc_list[KF_bpf_obj_drop_impl];
+}
+
+static bool is_bpf_percpu_obj_drop_kfunc(u32 func_id)
+{
+       return func_id == special_kfunc_list[KF_bpf_percpu_obj_drop] ||
+              func_id == special_kfunc_list[KF_bpf_percpu_obj_drop_impl];
+}
+
+static bool is_bpf_refcount_acquire_kfunc(u32 func_id)
+{
+       return func_id == special_kfunc_list[KF_bpf_refcount_acquire] ||
+              func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl];
+}
+
+static bool is_bpf_list_push_kfunc(u32 func_id)
+{
+       return func_id == special_kfunc_list[KF_bpf_list_push_front] ||
+              func_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
+              func_id == special_kfunc_list[KF_bpf_list_push_back] ||
+              func_id == special_kfunc_list[KF_bpf_list_push_back_impl];
+}
+
+static bool is_bpf_rbtree_add_kfunc(u32 func_id)
+{
+       return func_id == special_kfunc_list[KF_bpf_rbtree_add] ||
+              func_id == special_kfunc_list[KF_bpf_rbtree_add_impl];
+}
+
 static bool is_task_work_add_kfunc(u32 func_id)
 {
        return func_id == special_kfunc_list[KF_bpf_task_work_schedule_signal] ||
@@ -12684,10 +12766,8 @@ static bool is_task_work_add_kfunc(u32 func_id)
 
 static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta)
 {
-       if (meta->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl] &&
-           meta->arg_owning_ref) {
+       if (is_bpf_refcount_acquire_kfunc(meta->func_id) && meta->arg_owning_ref)
                return false;
-       }
 
        return meta->kfunc_flags & KF_RET_NULL;
 }
@@ -13075,8 +13155,7 @@ static int check_reg_allocation_locked(struct bpf_verifier_env *env, struct bpf_
 
 static bool is_bpf_list_api_kfunc(u32 btf_id)
 {
-       return btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
-              btf_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
+       return is_bpf_list_push_kfunc(btf_id) ||
               btf_id == special_kfunc_list[KF_bpf_list_pop_front] ||
               btf_id == special_kfunc_list[KF_bpf_list_pop_back] ||
               btf_id == special_kfunc_list[KF_bpf_list_front] ||
@@ -13085,7 +13164,7 @@ static bool is_bpf_list_api_kfunc(u32 btf_id)
 
 static bool is_bpf_rbtree_api_kfunc(u32 btf_id)
 {
-       return btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl] ||
+       return is_bpf_rbtree_add_kfunc(btf_id) ||
               btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
               btf_id == special_kfunc_list[KF_bpf_rbtree_first] ||
               btf_id == special_kfunc_list[KF_bpf_rbtree_root] ||
@@ -13102,8 +13181,9 @@ static bool is_bpf_iter_num_api_kfunc(u32 btf_id)
 
 static bool is_bpf_graph_api_kfunc(u32 btf_id)
 {
-       return is_bpf_list_api_kfunc(btf_id) || is_bpf_rbtree_api_kfunc(btf_id) ||
-              btf_id == special_kfunc_list[KF_bpf_refcount_acquire_impl];
+       return is_bpf_list_api_kfunc(btf_id) ||
+              is_bpf_rbtree_api_kfunc(btf_id) ||
+              is_bpf_refcount_acquire_kfunc(btf_id);
 }
 
 static bool is_bpf_res_spin_lock_kfunc(u32 btf_id)
@@ -13136,7 +13216,7 @@ static bool kfunc_spin_allowed(u32 btf_id)
 
 static bool is_sync_callback_calling_kfunc(u32 btf_id)
 {
-       return btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl];
+       return is_bpf_rbtree_add_kfunc(btf_id);
 }
 
 static bool is_async_callback_calling_kfunc(u32 btf_id)
@@ -13200,12 +13280,11 @@ static bool check_kfunc_is_graph_node_api(struct bpf_verifier_env *env,
 
        switch (node_field_type) {
        case BPF_LIST_NODE:
-               ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
-                      kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_back_impl]);
+               ret = is_bpf_list_push_kfunc(kfunc_btf_id);
                break;
        case BPF_RB_NODE:
-               ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
-                      kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl] ||
+               ret = (is_bpf_rbtree_add_kfunc(kfunc_btf_id) ||
+                      kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
                       kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_left] ||
                       kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_right]);
                break;
@@ -13422,11 +13501,6 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_
                bool is_ret_buf_sz = false;
                int kf_arg_type;
 
-               t = btf_type_skip_modifiers(btf, args[i].type, NULL);
-
-               if (is_kfunc_arg_ignore(btf, &args[i]))
-                       continue;
-
                if (is_kfunc_arg_prog_aux(btf, &args[i])) {
                        /* Reject repeated use bpf_prog_aux */
                        if (meta->arg_prog) {
@@ -13438,6 +13512,11 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_
                        continue;
                }
 
+               if (is_kfunc_arg_ignore(btf, &args[i]) || is_kfunc_arg_implicit(meta, i))
+                       continue;
+
+               t = btf_type_skip_modifiers(btf, args[i].type, NULL);
+
                if (btf_type_is_scalar(t)) {
                        if (reg->type != SCALAR_VALUE) {
                                verbose(env, "R%d is not a scalar\n", regno);
@@ -13612,13 +13691,13 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_
                        break;
                case KF_ARG_PTR_TO_ALLOC_BTF_ID:
                        if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC)) {
-                               if (meta->func_id != special_kfunc_list[KF_bpf_obj_drop_impl]) {
-                                       verbose(env, "arg#%d expected for bpf_obj_drop_impl()\n", i);
+                               if (!is_bpf_obj_drop_kfunc(meta->func_id)) {
+                                       verbose(env, "arg#%d expected for bpf_obj_drop()\n", i);
                                        return -EINVAL;
                                }
                        } else if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC | MEM_PERCPU)) {
-                               if (meta->func_id != special_kfunc_list[KF_bpf_percpu_obj_drop_impl]) {
-                                       verbose(env, "arg#%d expected for bpf_percpu_obj_drop_impl()\n", i);
+                               if (!is_bpf_percpu_obj_drop_kfunc(meta->func_id)) {
+                                       verbose(env, "arg#%d expected for bpf_percpu_obj_drop()\n", i);
                                        return -EINVAL;
                                }
                        } else {
@@ -13744,7 +13823,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_
                                return ret;
                        break;
                case KF_ARG_PTR_TO_RB_NODE:
-                       if (meta->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+                       if (is_bpf_rbtree_add_kfunc(meta->func_id)) {
                                if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
                                        verbose(env, "arg#%d expected pointer to allocated object\n", i);
                                        return -EINVAL;
@@ -13981,13 +14060,12 @@ static int check_special_kfunc(struct bpf_verifier_env *env, struct bpf_kfunc_ca
        if (meta->btf != btf_vmlinux)
                return 0;
 
-       if (meta->func_id == special_kfunc_list[KF_bpf_obj_new_impl] ||
-           meta->func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) {
+       if (is_bpf_obj_new_kfunc(meta->func_id) || is_bpf_percpu_obj_new_kfunc(meta->func_id)) {
                struct btf_struct_meta *struct_meta;
                struct btf *ret_btf;
                u32 ret_btf_id;
 
-               if (meta->func_id == special_kfunc_list[KF_bpf_obj_new_impl] && !bpf_global_ma_set)
+               if (is_bpf_obj_new_kfunc(meta->func_id) && !bpf_global_ma_set)
                        return -ENOMEM;
 
                if (((u64)(u32)meta->arg_constant.value) != meta->arg_constant.value) {
@@ -14010,7 +14088,7 @@ static int check_special_kfunc(struct bpf_verifier_env *env, struct bpf_kfunc_ca
                        return -EINVAL;
                }
 
-               if (meta->func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) {
+               if (is_bpf_percpu_obj_new_kfunc(meta->func_id)) {
                        if (ret_t->size > BPF_GLOBAL_PERCPU_MA_MAX_SIZE) {
                                verbose(env, "bpf_percpu_obj_new type size (%d) is greater than %d\n",
                                        ret_t->size, BPF_GLOBAL_PERCPU_MA_MAX_SIZE);
@@ -14040,7 +14118,7 @@ static int check_special_kfunc(struct bpf_verifier_env *env, struct bpf_kfunc_ca
                }
 
                struct_meta = btf_find_struct_meta(ret_btf, ret_btf_id);
-               if (meta->func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) {
+               if (is_bpf_percpu_obj_new_kfunc(meta->func_id)) {
                        if (!__btf_type_is_scalar_struct(env, ret_btf, ret_t, 0)) {
                                verbose(env, "bpf_percpu_obj_new type ID argument must be of a struct of scalars\n");
                                return -EINVAL;
@@ -14056,12 +14134,12 @@ static int check_special_kfunc(struct bpf_verifier_env *env, struct bpf_kfunc_ca
                regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC;
                regs[BPF_REG_0].btf = ret_btf;
                regs[BPF_REG_0].btf_id = ret_btf_id;
-               if (meta->func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl])
+               if (is_bpf_percpu_obj_new_kfunc(meta->func_id))
                        regs[BPF_REG_0].type |= MEM_PERCPU;
 
                insn_aux->obj_new_size = ret_t->size;
                insn_aux->kptr_struct_meta = struct_meta;
-       } else if (meta->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]) {
+       } else if (is_bpf_refcount_acquire_kfunc(meta->func_id)) {
                mark_reg_known_zero(env, regs, BPF_REG_0);
                regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC;
                regs[BPF_REG_0].btf = meta->arg_btf;
@@ -14227,7 +14305,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
        if (err < 0)
                return err;
 
-       if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+       if (is_bpf_rbtree_add_kfunc(meta.func_id)) {
                err = push_callback_call(env, insn, insn_idx, meta.subprogno,
                                         set_rbtree_add_callback_state);
                if (err) {
@@ -14331,9 +14409,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
                        return err;
        }
 
-       if (meta.func_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
-           meta.func_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
-           meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+       if (is_bpf_list_push_kfunc(meta.func_id) || is_bpf_rbtree_add_kfunc(meta.func_id)) {
                release_ref_obj_id = regs[BPF_REG_2].ref_obj_id;
                insn_aux->insert_off = regs[BPF_REG_2].var_off.value;
                insn_aux->kptr_struct_meta = btf_find_struct_meta(meta.arg_btf, meta.arg_btf_id);
@@ -14381,11 +14457,10 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
        t = btf_type_skip_modifiers(desc_btf, meta.func_proto->type, NULL);
 
        if (is_kfunc_acquire(&meta) && !btf_type_is_struct_ptr(meta.btf, t)) {
-               /* Only exception is bpf_obj_new_impl */
                if (meta.btf != btf_vmlinux ||
-                   (meta.func_id != special_kfunc_list[KF_bpf_obj_new_impl] &&
-                    meta.func_id != special_kfunc_list[KF_bpf_percpu_obj_new_impl] &&
-                    meta.func_id != special_kfunc_list[KF_bpf_refcount_acquire_impl])) {
+                   (!is_bpf_obj_new_kfunc(meta.func_id) &&
+                    !is_bpf_percpu_obj_new_kfunc(meta.func_id) &&
+                    !is_bpf_refcount_acquire_kfunc(meta.func_id))) {
                        verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n");
                        return -EINVAL;
                }
@@ -14496,8 +14571,8 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
                        regs[BPF_REG_0].id = ++env->id_gen;
        } else if (btf_type_is_void(t)) {
                if (meta.btf == btf_vmlinux) {
-                       if (meta.func_id == special_kfunc_list[KF_bpf_obj_drop_impl] ||
-                           meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_drop_impl]) {
+                       if (is_bpf_obj_drop_kfunc(meta.func_id) ||
+                           is_bpf_percpu_obj_drop_kfunc(meta.func_id)) {
                                insn_aux->kptr_struct_meta =
                                        btf_find_struct_meta(meta.arg_btf,
                                                             meta.arg_btf_id);
@@ -23324,13 +23399,12 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
        if (!bpf_jit_supports_far_kfunc_call())
                insn->imm = BPF_CALL_IMM(desc->addr);
 
-       if (desc->func_id == special_kfunc_list[KF_bpf_obj_new_impl] ||
-           desc->func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) {
+       if (is_bpf_obj_new_kfunc(desc->func_id) || is_bpf_percpu_obj_new_kfunc(desc->func_id)) {
                struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
                struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) };
                u64 obj_new_size = env->insn_aux_data[insn_idx].obj_new_size;
 
-               if (desc->func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl] && kptr_struct_meta) {
+               if (is_bpf_percpu_obj_new_kfunc(desc->func_id) && kptr_struct_meta) {
                        verifier_bug(env, "NULL kptr_struct_meta expected at insn_idx %d",
                                     insn_idx);
                        return -EFAULT;
@@ -23341,20 +23415,19 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
                insn_buf[2] = addr[1];
                insn_buf[3] = *insn;
                *cnt = 4;
-       } else if (desc->func_id == special_kfunc_list[KF_bpf_obj_drop_impl] ||
-                  desc->func_id == special_kfunc_list[KF_bpf_percpu_obj_drop_impl] ||
-                  desc->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]) {
+       } else if (is_bpf_obj_drop_kfunc(desc->func_id) ||
+                  is_bpf_percpu_obj_drop_kfunc(desc->func_id) ||
+                  is_bpf_refcount_acquire_kfunc(desc->func_id)) {
                struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
                struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) };
 
-               if (desc->func_id == special_kfunc_list[KF_bpf_percpu_obj_drop_impl] && kptr_struct_meta) {
+               if (is_bpf_percpu_obj_drop_kfunc(desc->func_id) && kptr_struct_meta) {
                        verifier_bug(env, "NULL kptr_struct_meta expected at insn_idx %d",
                                     insn_idx);
                        return -EFAULT;
                }
 
-               if (desc->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl] &&
-                   !kptr_struct_meta) {
+               if (is_bpf_refcount_acquire_kfunc(desc->func_id) && !kptr_struct_meta) {
                        verifier_bug(env, "kptr_struct_meta expected at insn_idx %d",
                                     insn_idx);
                        return -EFAULT;
@@ -23364,15 +23437,14 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
                insn_buf[1] = addr[1];
                insn_buf[2] = *insn;
                *cnt = 3;
-       } else if (desc->func_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
-                  desc->func_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
-                  desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+       } else if (is_bpf_list_push_kfunc(desc->func_id) ||
+                  is_bpf_rbtree_add_kfunc(desc->func_id)) {
                struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
                int struct_meta_reg = BPF_REG_3;
                int node_offset_reg = BPF_REG_4;
 
                /* rbtree_add has extra 'less' arg, so args-to-fixup are in diff regs */
-               if (desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+               if (is_bpf_rbtree_add_kfunc(desc->func_id)) {
                        struct_meta_reg = BPF_REG_4;
                        node_offset_reg = BPF_REG_5;
                }

diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index 5208f650080fe02b85b617e081c83fec5ef45ca6..f8a91fa7584f4cae50927df1f46c78a45cb1f3e6 100644 (file)
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -1065,6 +1065,7 @@ static bool is_kf_implicit_arg(const struct btf *btf, const struct btf_param *p)
 {
        static const char *const kf_implicit_arg_types[] = {
                "bpf_prog_aux",
+               "btf_struct_meta",
        };
        const struct btf_type *t;
        const char *name;

diff --git a/tools/testing/selftests/bpf/progs/percpu_alloc_fail.c b/tools/testing/selftests/bpf/progs/percpu_alloc_fail.c
index f2b8eb2ff76f7a98a088ae20b4f8afc3b98ab941..81813c724fa962584f91b99746f7d2557d65270f 100644 (file)
--- a/tools/testing/selftests/bpf/progs/percpu_alloc_fail.c
+++ b/tools/testing/selftests/bpf/progs/percpu_alloc_fail.c
@@ -110,7 +110,7 @@ int BPF_PROG(test_array_map_3)
 }
 
 SEC("?fentry.s/bpf_fentry_test1")
-__failure __msg("arg#0 expected for bpf_percpu_obj_drop_impl()")
+__failure __msg("arg#0 expected for bpf_percpu_obj_drop()")
 int BPF_PROG(test_array_map_4)
 {
        struct val_t __percpu_kptr *p;
@@ -124,7 +124,7 @@ int BPF_PROG(test_array_map_4)
 }
 
 SEC("?fentry.s/bpf_fentry_test1")
-__failure __msg("arg#0 expected for bpf_obj_drop_impl()")
+__failure __msg("arg#0 expected for bpf_obj_drop()")
 int BPF_PROG(test_array_map_5)
 {
        struct val_t *p;