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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> | |
3ec24776 | 26 | #include <linux/completion.h> |
b700e7f0 | 27 | |
7e545d6e JY |
28 | #if IS_ENABLED(CONFIG_LIVEPATCH) |
29 | ||
b700e7f0 SJ |
30 | #include <asm/livepatch.h> |
31 | ||
d83a7cb3 JP |
32 | /* task patch states */ |
33 | #define KLP_UNDEFINED -1 | |
34 | #define KLP_UNPATCHED 0 | |
35 | #define KLP_PATCHED 1 | |
36 | ||
b700e7f0 SJ |
37 | /** |
38 | * struct klp_func - function structure for live patching | |
39 | * @old_name: name of the function to be patched | |
40 | * @new_func: pointer to the patched function code | |
b2b018ef CA |
41 | * @old_sympos: a hint indicating which symbol position the old function |
42 | * can be found (optional) | |
d83a7cb3 | 43 | * @immediate: patch the func immediately, bypassing safety mechanisms |
b2b018ef | 44 | * @old_addr: the address of the function being patched |
b700e7f0 | 45 | * @kobj: kobject for sysfs resources |
3c33f5b9 | 46 | * @stack_node: list node for klp_ops func_stack list |
f5e547f4 JP |
47 | * @old_size: size of the old function |
48 | * @new_size: size of the new function | |
0dade9f3 | 49 | * @patched: the func has been added to the klp_ops list |
d83a7cb3 JP |
50 | * @transition: the func is currently being applied or reverted |
51 | * | |
52 | * The patched and transition variables define the func's patching state. When | |
53 | * patching, a func is always in one of the following states: | |
54 | * | |
55 | * patched=0 transition=0: unpatched | |
56 | * patched=0 transition=1: unpatched, temporary starting state | |
57 | * patched=1 transition=1: patched, may be visible to some tasks | |
58 | * patched=1 transition=0: patched, visible to all tasks | |
59 | * | |
60 | * And when unpatching, it goes in the reverse order: | |
61 | * | |
62 | * patched=1 transition=0: patched, visible to all tasks | |
63 | * patched=1 transition=1: patched, may be visible to some tasks | |
64 | * patched=0 transition=1: unpatched, temporary ending state | |
65 | * patched=0 transition=0: unpatched | |
b700e7f0 SJ |
66 | */ |
67 | struct klp_func { | |
68 | /* external */ | |
69 | const char *old_name; | |
70 | void *new_func; | |
71 | /* | |
b2b018ef CA |
72 | * The old_sympos field is optional and can be used to resolve |
73 | * duplicate symbol names in livepatch objects. If this field is zero, | |
74 | * it is expected the symbol is unique, otherwise patching fails. If | |
75 | * this value is greater than zero then that occurrence of the symbol | |
76 | * in kallsyms for the given object is used. | |
b700e7f0 | 77 | */ |
b2b018ef | 78 | unsigned long old_sympos; |
d83a7cb3 | 79 | bool immediate; |
b700e7f0 SJ |
80 | |
81 | /* internal */ | |
b2b018ef | 82 | unsigned long old_addr; |
b700e7f0 | 83 | struct kobject kobj; |
3c33f5b9 | 84 | struct list_head stack_node; |
f5e547f4 | 85 | unsigned long old_size, new_size; |
0dade9f3 | 86 | bool patched; |
d83a7cb3 | 87 | bool transition; |
b700e7f0 SJ |
88 | }; |
89 | ||
93862e38 JL |
90 | struct klp_object; |
91 | ||
92 | /** | |
93 | * struct klp_callbacks - pre/post live-(un)patch callback structure | |
94 | * @pre_patch: executed before code patching | |
95 | * @post_patch: executed after code patching | |
96 | * @pre_unpatch: executed before code unpatching | |
97 | * @post_unpatch: executed after code unpatching | |
98 | * @post_unpatch_enabled: flag indicating if post-unpatch callback | |
99 | * should run | |
100 | * | |
101 | * All callbacks are optional. Only the pre-patch callback, if provided, | |
102 | * will be unconditionally executed. If the parent klp_object fails to | |
103 | * patch for any reason, including a non-zero error status returned from | |
104 | * the pre-patch callback, no further callbacks will be executed. | |
105 | */ | |
106 | struct klp_callbacks { | |
107 | int (*pre_patch)(struct klp_object *obj); | |
108 | void (*post_patch)(struct klp_object *obj); | |
109 | void (*pre_unpatch)(struct klp_object *obj); | |
110 | void (*post_unpatch)(struct klp_object *obj); | |
111 | bool post_unpatch_enabled; | |
112 | }; | |
113 | ||
b700e7f0 SJ |
114 | /** |
115 | * struct klp_object - kernel object structure for live patching | |
116 | * @name: module name (or NULL for vmlinux) | |
b700e7f0 | 117 | * @funcs: function entries for functions to be patched in the object |
93862e38 | 118 | * @callbacks: functions to be executed pre/post (un)patching |
b700e7f0 SJ |
119 | * @kobj: kobject for sysfs resources |
120 | * @mod: kernel module associated with the patched object | |
d83a7cb3 | 121 | * (NULL for vmlinux) |
0dade9f3 | 122 | * @patched: the object's funcs have been added to the klp_ops list |
b700e7f0 SJ |
123 | */ |
124 | struct klp_object { | |
125 | /* external */ | |
126 | const char *name; | |
b700e7f0 | 127 | struct klp_func *funcs; |
93862e38 | 128 | struct klp_callbacks callbacks; |
b700e7f0 SJ |
129 | |
130 | /* internal */ | |
cad706df | 131 | struct kobject kobj; |
b700e7f0 | 132 | struct module *mod; |
0dade9f3 | 133 | bool patched; |
b700e7f0 SJ |
134 | }; |
135 | ||
136 | /** | |
137 | * struct klp_patch - patch structure for live patching | |
138 | * @mod: reference to the live patch module | |
139 | * @objs: object entries for kernel objects to be patched | |
d83a7cb3 | 140 | * @immediate: patch all funcs immediately, bypassing safety mechanisms |
b700e7f0 SJ |
141 | * @list: list node for global list of registered patches |
142 | * @kobj: kobject for sysfs resources | |
0dade9f3 | 143 | * @enabled: the patch is enabled (but operation may be incomplete) |
3ec24776 | 144 | * @finish: for waiting till it is safe to remove the patch module |
b700e7f0 SJ |
145 | */ |
146 | struct klp_patch { | |
147 | /* external */ | |
148 | struct module *mod; | |
149 | struct klp_object *objs; | |
d83a7cb3 | 150 | bool immediate; |
b700e7f0 SJ |
151 | |
152 | /* internal */ | |
153 | struct list_head list; | |
154 | struct kobject kobj; | |
0dade9f3 | 155 | bool enabled; |
3ec24776 | 156 | struct completion finish; |
b700e7f0 SJ |
157 | }; |
158 | ||
8cdd043a | 159 | #define klp_for_each_object(patch, obj) \ |
f09d9086 | 160 | for (obj = patch->objs; obj->funcs || obj->name; obj++) |
8cdd043a JS |
161 | |
162 | #define klp_for_each_func(obj, func) \ | |
f09d9086 MB |
163 | for (func = obj->funcs; \ |
164 | func->old_name || func->new_func || func->old_sympos; \ | |
165 | func++) | |
8cdd043a | 166 | |
4421f8f0 MB |
167 | int klp_register_patch(struct klp_patch *); |
168 | int klp_unregister_patch(struct klp_patch *); | |
169 | int klp_enable_patch(struct klp_patch *); | |
170 | int klp_disable_patch(struct klp_patch *); | |
b700e7f0 | 171 | |
255e732c JY |
172 | void arch_klp_init_object_loaded(struct klp_patch *patch, |
173 | struct klp_object *obj); | |
174 | ||
7e545d6e JY |
175 | /* Called from the module loader during module coming/going states */ |
176 | int klp_module_coming(struct module *mod); | |
177 | void klp_module_going(struct module *mod); | |
178 | ||
d83a7cb3 | 179 | void klp_copy_process(struct task_struct *child); |
46c5a011 JP |
180 | void klp_update_patch_state(struct task_struct *task); |
181 | ||
d83a7cb3 JP |
182 | static inline bool klp_patch_pending(struct task_struct *task) |
183 | { | |
184 | return test_tsk_thread_flag(task, TIF_PATCH_PENDING); | |
185 | } | |
186 | ||
187 | static inline bool klp_have_reliable_stack(void) | |
188 | { | |
189 | return IS_ENABLED(CONFIG_STACKTRACE) && | |
190 | IS_ENABLED(CONFIG_HAVE_RELIABLE_STACKTRACE); | |
191 | } | |
192 | ||
439e7271 JL |
193 | void *klp_shadow_get(void *obj, unsigned long id); |
194 | void *klp_shadow_alloc(void *obj, unsigned long id, void *data, | |
195 | size_t size, gfp_t gfp_flags); | |
196 | void *klp_shadow_get_or_alloc(void *obj, unsigned long id, void *data, | |
197 | size_t size, gfp_t gfp_flags); | |
198 | void klp_shadow_free(void *obj, unsigned long id); | |
199 | void klp_shadow_free_all(unsigned long id); | |
200 | ||
7e545d6e JY |
201 | #else /* !CONFIG_LIVEPATCH */ |
202 | ||
203 | static inline int klp_module_coming(struct module *mod) { return 0; } | |
46c5a011 | 204 | static inline void klp_module_going(struct module *mod) {} |
d83a7cb3 | 205 | static inline bool klp_patch_pending(struct task_struct *task) { return false; } |
46c5a011 | 206 | static inline void klp_update_patch_state(struct task_struct *task) {} |
d83a7cb3 | 207 | static inline void klp_copy_process(struct task_struct *child) {} |
7e545d6e JY |
208 | |
209 | #endif /* CONFIG_LIVEPATCH */ | |
210 | ||
b700e7f0 | 211 | #endif /* _LINUX_LIVEPATCH_H_ */ |