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Seth Jenningsb700e7f2014-12-16 11:58:19 -06001/*
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
Jessica Yu7e545d62016-03-16 20:55:39 -040027#if IS_ENABLED(CONFIG_LIVEPATCH)
28
Seth Jenningsb700e7f2014-12-16 11:58:19 -060029#include <asm/livepatch.h>
30
31enum 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
Chris J Argesb2b018e2015-12-01 20:40:54 -060040 * @old_sympos: a hint indicating which symbol position the old function
41 * can be found (optional)
42 * @old_addr: the address of the function being patched
Seth Jenningsb700e7f2014-12-16 11:58:19 -060043 * @kobj: kobject for sysfs resources
Seth Jenningsb700e7f2014-12-16 11:58:19 -060044 * @state: tracks function-level patch application state
Josh Poimboeuf3c33f5b2015-01-20 09:26:19 -060045 * @stack_node: list node for klp_ops func_stack list
Seth Jenningsb700e7f2014-12-16 11:58:19 -060046 */
47struct klp_func {
48 /* external */
49 const char *old_name;
50 void *new_func;
51 /*
Chris J Argesb2b018e2015-12-01 20:40:54 -060052 * The old_sympos field is optional and can be used to resolve
53 * duplicate symbol names in livepatch objects. If this field is zero,
54 * it is expected the symbol is unique, otherwise patching fails. If
55 * this value is greater than zero then that occurrence of the symbol
56 * in kallsyms for the given object is used.
Seth Jenningsb700e7f2014-12-16 11:58:19 -060057 */
Chris J Argesb2b018e2015-12-01 20:40:54 -060058 unsigned long old_sympos;
Seth Jenningsb700e7f2014-12-16 11:58:19 -060059
60 /* internal */
Chris J Argesb2b018e2015-12-01 20:40:54 -060061 unsigned long old_addr;
Seth Jenningsb700e7f2014-12-16 11:58:19 -060062 struct kobject kobj;
Seth Jenningsb700e7f2014-12-16 11:58:19 -060063 enum klp_state state;
Josh Poimboeuf3c33f5b2015-01-20 09:26:19 -060064 struct list_head stack_node;
Seth Jenningsb700e7f2014-12-16 11:58:19 -060065};
66
67/**
68 * struct klp_reloc - relocation structure for live patching
69 * @loc: address where the relocation will be written
Chris J Arges064c89d2015-12-01 20:40:55 -060070 * @sympos: position in kallsyms to disambiguate symbols (optional)
Seth Jenningsb700e7f2014-12-16 11:58:19 -060071 * @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 */
76struct klp_reloc {
77 unsigned long loc;
Chris J Arges064c89d2015-12-01 20:40:55 -060078 unsigned long sympos;
Seth Jenningsb700e7f2014-12-16 11:58:19 -060079 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 */
95struct klp_object {
96 /* external */
97 const char *name;
98 struct klp_reloc *relocs;
99 struct klp_func *funcs;
100
101 /* internal */
Miroslav Benescad706d2015-05-19 12:01:18 +0200102 struct kobject kobj;
Seth Jenningsb700e7f2014-12-16 11:58:19 -0600103 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 */
115struct 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
Jiri Slaby8cdd0432015-05-19 12:01:19 +0200126#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
Miroslav Benes4421f8f2015-02-18 15:21:07 +0100132int klp_register_patch(struct klp_patch *);
133int klp_unregister_patch(struct klp_patch *);
134int klp_enable_patch(struct klp_patch *);
135int klp_disable_patch(struct klp_patch *);
Seth Jenningsb700e7f2014-12-16 11:58:19 -0600136
Jessica Yu7e545d62016-03-16 20:55:39 -0400137/* Called from the module loader during module coming/going states */
138int klp_module_coming(struct module *mod);
139void klp_module_going(struct module *mod);
140
141#else /* !CONFIG_LIVEPATCH */
142
143static inline int klp_module_coming(struct module *mod) { return 0; }
144static inline void klp_module_going(struct module *mod) { }
145
146#endif /* CONFIG_LIVEPATCH */
147
Seth Jenningsb700e7f2014-12-16 11:58:19 -0600148#endif /* _LINUX_LIVEPATCH_H_ */