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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 | ||
7e545d6e JY |
27 | #if IS_ENABLED(CONFIG_LIVEPATCH) |
28 | ||
b700e7f0 SJ |
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 | |
b2b018ef CA |
40 | * @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 | |
b700e7f0 | 43 | * @kobj: kobject for sysfs resources |
b700e7f0 | 44 | * @state: tracks function-level patch application state |
3c33f5b9 | 45 | * @stack_node: list node for klp_ops func_stack list |
b700e7f0 SJ |
46 | */ |
47 | struct klp_func { | |
48 | /* external */ | |
49 | const char *old_name; | |
50 | void *new_func; | |
51 | /* | |
b2b018ef CA |
52 | * 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. | |
b700e7f0 | 57 | */ |
b2b018ef | 58 | unsigned long old_sympos; |
b700e7f0 SJ |
59 | |
60 | /* internal */ | |
b2b018ef | 61 | unsigned long old_addr; |
b700e7f0 | 62 | struct kobject kobj; |
b700e7f0 | 63 | enum klp_state state; |
3c33f5b9 | 64 | struct list_head stack_node; |
b700e7f0 SJ |
65 | }; |
66 | ||
67 | /** | |
68 | * struct klp_reloc - relocation structure for live patching | |
69 | * @loc: address where the relocation will be written | |
064c89df | 70 | * @sympos: position in kallsyms to disambiguate symbols (optional) |
b700e7f0 SJ |
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; | |
064c89df | 78 | unsigned long sympos; |
b700e7f0 SJ |
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 | |
7e545d6e JY |
137 | /* Called from the module loader during module coming/going states */ |
138 | int klp_module_coming(struct module *mod); | |
139 | void klp_module_going(struct module *mod); | |
140 | ||
141 | #else /* !CONFIG_LIVEPATCH */ | |
142 | ||
143 | static inline int klp_module_coming(struct module *mod) { return 0; } | |
144 | static inline void klp_module_going(struct module *mod) { } | |
145 | ||
146 | #endif /* CONFIG_LIVEPATCH */ | |
147 | ||
b700e7f0 | 148 | #endif /* _LINUX_LIVEPATCH_H_ */ |