/*
   * 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_addr:	a hint conveying at what address the old function
   *		can be found (optional, vmlinux patches only)
   * @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_addr field is optional and can be used to resolve
  	 * duplicate symbol names in the vmlinux object.  If this
  	 * information is not present, the symbol is located by name
  	 * with kallsyms. If the name is not unique and old_addr is
  	 * not provided, the patch application fails as there is no
  	 * way to resolve the ambiguity.
  	 */
  	unsigned long old_addr;
  
  	/* internal */
  	struct kobject kobj;

  	enum klp_state state;

  	struct list_head stack_node;

  };
  
  /**
   * struct klp_reloc - relocation structure for live patching
   * @loc:	address where the relocation will be written
   * @val:	address of the referenced symbol (optional,
   *		vmlinux	patches only)
   * @type:	ELF relocation type
   * @name:	name of the referenced symbol (for lookup/verification)
   * @addend:	offset from the referenced symbol
   * @external:	symbol is either exported or within the live patch module itself
   */
  struct klp_reloc {
  	unsigned long loc;
  	unsigned long val;
  	unsigned long type;
  	const char *name;
  	int addend;
  	int external;
  };
  
  /**
   * struct klp_object - kernel object structure for live patching
   * @name:	module name (or NULL for vmlinux)
   * @relocs:	relocation entries to be applied at load time
   * @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_reloc *relocs;
  	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;
  };

  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 *);

  #endif /* CONFIG_LIVEPATCH */

  
  #endif /* _LINUX_LIVEPATCH_H_ */