/* SPDX-License-Identifier: GPL-2.0 */
  /* Copyright (c) 2018 Facebook */
  
  #ifndef _LINUX_BTF_H
  #define _LINUX_BTF_H 1
  
  #include <linux/types.h>
  
  struct btf;
  struct btf_member;
  struct btf_type;
  union bpf_attr;
  
  extern const struct file_operations btf_fops;
  
  void btf_put(struct btf *btf);
  int btf_new_fd(const union bpf_attr *attr);
  struct btf *btf_get_by_fd(int fd);
  int btf_get_info_by_fd(const struct btf *btf,
  		       const union bpf_attr *attr,
  		       union bpf_attr __user *uattr);
  /* Figure out the size of a type_id.  If type_id is a modifier
   * (e.g. const), it will be resolved to find out the type with size.
   *
   * For example:
   * In describing "const void *",  type_id is "const" and "const"
   * refers to "void *".  The return type will be "void *".
   *
   * If type_id is a simple "int", then return type will be "int".
   *
   * @btf: struct btf object
   * @type_id: Find out the size of type_id. The type_id of the return
   *           type is set to *type_id.
   * @ret_size: It can be NULL.  If not NULL, the size of the return
   *            type is set to *ret_size.
   * Return: The btf_type (resolved to another type with size info if needed).
   *         NULL is returned if type_id itself does not have size info
   *         (e.g. void) or it cannot be resolved to another type that
   *         has size info.
   *         *type_id and *ret_size will not be changed in the
   *         NULL return case.
   */
  const struct btf_type *btf_type_id_size(const struct btf *btf,
  					u32 *type_id,
  					u32 *ret_size);
  void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
  		       struct seq_file *m);
  int btf_get_fd_by_id(u32 id);
  u32 btf_id(const struct btf *btf);
  bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
  			   const struct btf_member *m,
  			   u32 expected_offset, u32 expected_size);
  int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t);
  bool btf_type_is_void(const struct btf_type *t);
  
  #ifdef CONFIG_BPF_SYSCALL
  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);
  #else
  static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
  						    u32 type_id)
  {
  	return NULL;
  }
  static inline const char *btf_name_by_offset(const struct btf *btf,
  					     u32 offset)
  {
  	return NULL;
  }
  #endif
  
  #endif