/*
   * livepatch.h - Kernel Live Patching Core
   *
   * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
   * Copyright (C) 2014 SUSE
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version 2
   * of the License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, see <http://www.gnu.org/licenses/>.
   */
  
  #ifndef _LINUX_LIVEPATCH_H_
  #define _LINUX_LIVEPATCH_H_
  
  #include <linux/module.h>
  #include <linux/ftrace.h>

  #if IS_ENABLED(CONFIG_LIVEPATCH)

  #include <asm/livepatch.h>
  
  enum klp_state {
  	KLP_DISABLED,
  	KLP_ENABLED
  };
  
  /**
   * struct klp_func - function structure for live patching
   * @old_name:	name of the function to be patched
   * @new_func:	pointer to the patched function code

   * @old_sympos: a hint indicating which symbol position the old function
   *		can be found (optional)
   * @old_addr:	the address of the function being patched

   * @kobj:	kobject for sysfs resources

   * @state:	tracks function-level patch application state

   * @stack_node:	list node for klp_ops func_stack list

   */
  struct klp_func {
  	/* external */
  	const char *old_name;
  	void *new_func;
  	/*

  	 * The old_sympos field is optional and can be used to resolve
  	 * duplicate symbol names in livepatch objects. If this field is zero,
  	 * it is expected the symbol is unique, otherwise patching fails. If
  	 * this value is greater than zero then that occurrence of the symbol
  	 * in kallsyms for the given object is used.

  	 */

  	unsigned long old_sympos;

  
  	/* internal */

  	unsigned long old_addr;

  	struct kobject kobj;

  	enum klp_state state;

  	struct list_head stack_node;

  };
  
  /**

   * struct klp_object - kernel object structure for live patching
   * @name:	module name (or NULL for vmlinux)

   * @funcs:	function entries for functions to be patched in the object
   * @kobj:	kobject for sysfs resources
   * @mod:	kernel module associated with the patched object
   * 		(NULL for vmlinux)
   * @state:	tracks object-level patch application state
   */
  struct klp_object {
  	/* external */
  	const char *name;

  	struct klp_func *funcs;
  
  	/* internal */

  	struct kobject kobj;

  	struct module *mod;
  	enum klp_state state;
  };
  
  /**
   * struct klp_patch - patch structure for live patching
   * @mod:	reference to the live patch module
   * @objs:	object entries for kernel objects to be patched
   * @list:	list node for global list of registered patches
   * @kobj:	kobject for sysfs resources
   * @state:	tracks patch-level application state
   */
  struct klp_patch {
  	/* external */
  	struct module *mod;
  	struct klp_object *objs;
  
  	/* internal */
  	struct list_head list;
  	struct kobject kobj;
  	enum klp_state state;
  };

  #define klp_for_each_object(patch, obj) \

  	for (obj = patch->objs; obj->funcs || obj->name; obj++)

  
  #define klp_for_each_func(obj, func) \

  	for (func = obj->funcs; \
  	     func->old_name || func->new_func || func->old_sympos; \
  	     func++)

  int klp_register_patch(struct klp_patch *);
  int klp_unregister_patch(struct klp_patch *);
  int klp_enable_patch(struct klp_patch *);
  int klp_disable_patch(struct klp_patch *);

  void arch_klp_init_object_loaded(struct klp_patch *patch,
  				 struct klp_object *obj);

  /* Called from the module loader during module coming/going states */
  int klp_module_coming(struct module *mod);
  void klp_module_going(struct module *mod);
  
  #else /* !CONFIG_LIVEPATCH */
  
  static inline int klp_module_coming(struct module *mod) { return 0; }
  static inline void klp_module_going(struct module *mod) { }
  
  #endif /* CONFIG_LIVEPATCH */

  #endif /* _LINUX_LIVEPATCH_H_ */