[linux-2.6-block.git] / include / linux / livepatch.h

/*
 * 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;
};

#define klp_for_each_object(patch, obj) \
	for (obj = patch->objs; obj->funcs; obj++)

#define klp_for_each_func(obj, func) \
	for (func = obj->funcs; func->old_name; 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 *);

#endif /* CONFIG_LIVEPATCH */

#endif /* _LINUX_LIVEPATCH_H_ */
Commit	Line	Data
b700e7f0 SJ	1	/*
	2	* livepatch.h - Kernel Live Patching Core
	3	*
	4	* Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
	5	* Copyright (C) 2014 SUSE
	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License
	9	* as published by the Free Software Foundation; either version 2
	10	* of the License, or (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, see <http://www.gnu.org/licenses/>.
	19	*/
	20
	21	#ifndef _LINUX_LIVEPATCH_H_
	22	#define _LINUX_LIVEPATCH_H_
	23
	24	#include <linux/module.h>
	25	#include <linux/ftrace.h>
	26
12cf89b5	27	#if IS_ENABLED(CONFIG_LIVEPATCH)
b700e7f0 SJ	28
	29	#include <asm/livepatch.h>
	30
	31	enum klp_state {
	32	KLP_DISABLED,
	33	KLP_ENABLED
	34	};
	35
	36	/**
	37	* struct klp_func - function structure for live patching
	38	* @old_name: name of the function to be patched
	39	* @new_func: pointer to the patched function code
	40	* @old_addr: a hint conveying at what address the old function
	41	* can be found (optional, vmlinux patches only)
	42	* @kobj: kobject for sysfs resources
b700e7f0	43	* @state: tracks function-level patch application state
3c33f5b9	44	* @stack_node: list node for klp_ops func_stack list
b700e7f0 SJ	45	*/
	46	struct klp_func {
	47	/* external */
	48	const char *old_name;
	49	void *new_func;
	50	/*
	51	* The old_addr field is optional and can be used to resolve
	52	* duplicate symbol names in the vmlinux object. If this
	53	* information is not present, the symbol is located by name
	54	* with kallsyms. If the name is not unique and old_addr is
	55	* not provided, the patch application fails as there is no
	56	* way to resolve the ambiguity.
	57	*/
	58	unsigned long old_addr;
	59
	60	/* internal */
	61	struct kobject kobj;
b700e7f0	62	enum klp_state state;
3c33f5b9	63	struct list_head stack_node;
b700e7f0 SJ	64	};
	65
	66	/**
	67	* struct klp_reloc - relocation structure for live patching
	68	* @loc: address where the relocation will be written
	69	* @val: address of the referenced symbol (optional,
	70	* vmlinux patches only)
	71	* @type: ELF relocation type
	72	* @name: name of the referenced symbol (for lookup/verification)
	73	* @addend: offset from the referenced symbol
	74	* @external: symbol is either exported or within the live patch module itself
	75	*/
	76	struct klp_reloc {
	77	unsigned long loc;
	78	unsigned long val;
	79	unsigned long type;
	80	const char *name;
	81	int addend;
	82	int external;
	83	};
	84
	85	/**
	86	* struct klp_object - kernel object structure for live patching
	87	* @name: module name (or NULL for vmlinux)
	88	* @relocs: relocation entries to be applied at load time
	89	* @funcs: function entries for functions to be patched in the object
	90	* @kobj: kobject for sysfs resources
	91	* @mod: kernel module associated with the patched object
	92	* (NULL for vmlinux)
	93	* @state: tracks object-level patch application state
	94	*/
	95	struct klp_object {
	96	/* external */
	97	const char *name;
	98	struct klp_reloc *relocs;
	99	struct klp_func *funcs;
	100
	101	/* internal */
cad706df	102	struct kobject kobj;
b700e7f0 SJ	103	struct module *mod;
	104	enum klp_state state;
	105	};
	106
	107	/**
	108	* struct klp_patch - patch structure for live patching
	109	* @mod: reference to the live patch module
	110	* @objs: object entries for kernel objects to be patched
	111	* @list: list node for global list of registered patches
	112	* @kobj: kobject for sysfs resources
	113	* @state: tracks patch-level application state
	114	*/
	115	struct klp_patch {
	116	/* external */
	117	struct module *mod;
	118	struct klp_object *objs;
	119
	120	/* internal */
	121	struct list_head list;
	122	struct kobject kobj;
	123	enum klp_state state;
	124	};
	125
8cdd043a JS	126	#define klp_for_each_object(patch, obj) \
	127	for (obj = patch->objs; obj->funcs; obj++)
	128
	129	#define klp_for_each_func(obj, func) \
	130	for (func = obj->funcs; func->old_name; func++)
	131
4421f8f0 MB	132	int klp_register_patch(struct klp_patch *);
	133	int klp_unregister_patch(struct klp_patch *);
	134	int klp_enable_patch(struct klp_patch *);
	135	int klp_disable_patch(struct klp_patch *);
b700e7f0	136
12cf89b5	137	#endif /* CONFIG_LIVEPATCH */
b700e7f0 SJ	138
b700e7f0 SJ	139	#endif /* _LINUX_LIVEPATCH_H_ */