aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/include/linux/livepatch.h
blob: 9787a63b57accafffd9b2ffa84c81e1a7d665eaf (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/*
 * 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>

/**
 * 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
 * @stack_node:	list node for klp_ops func_stack list
 * @patched:	the func has been added to the klp_ops 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;
	struct list_head stack_node;
	bool patched;
};

/**
 * 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)
 * @patched:	the object's funcs have been added to the klp_ops list
 */
struct klp_object {
	/* external */
	const char *name;
	struct klp_func *funcs;

	/* internal */
	struct kobject kobj;
	struct module *mod;
	bool patched;
};

/**
 * 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
 * @enabled:	the patch is enabled (but operation may be incomplete)
 */
struct klp_patch {
	/* external */
	struct module *mod;
	struct klp_object *objs;

	/* internal */
	struct list_head list;
	struct kobject kobj;
	bool enabled;
};

#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);

void klp_update_patch_state(struct task_struct *task);

#else /* !CONFIG_LIVEPATCH */

static inline int klp_module_coming(struct module *mod) { return 0; }
static inline void klp_module_going(struct module *mod) {}
static inline void klp_update_patch_state(struct task_struct *task) {}

#endif /* CONFIG_LIVEPATCH */

#endif /* _LINUX_LIVEPATCH_H_ */