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/*
* 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>
enum klp_state {
KLP_DISABLED,
KLP_ENABLED
};
/**
* 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
* @state: tracks function-level patch application state
* @stack_node: list node for klp_ops func_stack 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;
enum klp_state state;
struct list_head stack_node;
};
/**
* struct klp_reloc - relocation structure for live patching
* @loc: address where the relocation will be written
* @sympos: position in kallsyms to disambiguate symbols (optional)
* @type: ELF relocation type
* @name: name of the referenced symbol (for lookup/verification)
* @addend: offset from the referenced symbol
* @external: symbol is either exported or within the live patch module itself
*/
struct klp_reloc {
unsigned long loc;
unsigned long sympos;
unsigned long type;
const char *name;
int addend;
int external;
};
/**
* struct klp_object - kernel object structure for live patching
* @name: module name (or NULL for vmlinux)
* @relocs: relocation entries to be applied at load time
* @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)
* @state: tracks object-level patch application state
*/
struct klp_object {
/* external */
const char *name;
struct klp_reloc *relocs;
struct klp_func *funcs;
/* internal */
struct kobject kobj;
struct module *mod;
enum klp_state state;
};
/**
* 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
* @state: tracks patch-level application state
*/
struct klp_patch {
/* external */
struct module *mod;
struct klp_object *objs;
/* internal */
struct list_head list;
struct kobject kobj;
enum klp_state state;
};
#define klp_for_each_object(patch, obj) \
for (obj = patch->objs; obj->funcs; obj++)
#define klp_for_each_func(obj, func) \
for (func = obj->funcs; func->old_name; 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 *);
/* Called from the module loader during module coming/going states */
int klp_module_coming(struct module *mod);
void klp_module_going(struct module *mod);
#else /* !CONFIG_LIVEPATCH */
static inline int klp_module_coming(struct module *mod) { return 0; }
static inline void klp_module_going(struct module *mod) { }
#endif /* CONFIG_LIVEPATCH */
#endif /* _LINUX_LIVEPATCH_H_ */
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