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 27 #if IS_ENABLED(CONFIG_LIVEPATCH) 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_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 43 * @kobj: kobject for sysfs resources 44 * @state: tracks function-level patch application state 45 * @stack_node: list node for klp_ops func_stack list 46 */ 47 struct klp_func { 48 /* external */ 49 const char *old_name; 50 void *new_func; 51 /* 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. 57 */ 58 unsigned long old_sympos; 59 60 /* internal */ 61 unsigned long old_addr; 62 struct kobject kobj; 63 enum klp_state state; 64 struct list_head stack_node; 65 }; 66 67 /** 68 * struct klp_object - kernel object structure for live patching 69 * @name: module name (or NULL for vmlinux) 70 * @funcs: function entries for functions to be patched in the object 71 * @kobj: kobject for sysfs resources 72 * @mod: kernel module associated with the patched object 73 * (NULL for vmlinux) 74 * @state: tracks object-level patch application state 75 */ 76 struct klp_object { 77 /* external */ 78 const char *name; 79 struct klp_func *funcs; 80 81 /* internal */ 82 struct kobject kobj; 83 struct module *mod; 84 enum klp_state state; 85 }; 86 87 /** 88 * struct klp_patch - patch structure for live patching 89 * @mod: reference to the live patch module 90 * @objs: object entries for kernel objects to be patched 91 * @list: list node for global list of registered patches 92 * @kobj: kobject for sysfs resources 93 * @state: tracks patch-level application state 94 */ 95 struct klp_patch { 96 /* external */ 97 struct module *mod; 98 struct klp_object *objs; 99 100 /* internal */ 101 struct list_head list; 102 struct kobject kobj; 103 enum klp_state state; 104 }; 105 106 #define klp_for_each_object(patch, obj) \ 107 for (obj = patch->objs; obj->funcs || obj->name; obj++) 108 109 #define klp_for_each_func(obj, func) \ 110 for (func = obj->funcs; \ 111 func->old_name || func->new_func || func->old_sympos; \ 112 func++) 113 114 int klp_register_patch(struct klp_patch *); 115 int klp_unregister_patch(struct klp_patch *); 116 int klp_enable_patch(struct klp_patch *); 117 int klp_disable_patch(struct klp_patch *); 118 119 /* Called from the module loader during module coming/going states */ 120 int klp_module_coming(struct module *mod); 121 void klp_module_going(struct module *mod); 122 123 #else /* !CONFIG_LIVEPATCH */ 124 125 static inline int klp_module_coming(struct module *mod) { return 0; } 126 static inline void klp_module_going(struct module *mod) { } 127 128 #endif /* CONFIG_LIVEPATCH */ 129 130 #endif /* _LINUX_LIVEPATCH_H_ */ 131