425595a7fc
Reuse module loader code to write relocations, thereby eliminating the need for architecture specific relocation code in livepatch. Specifically, reuse the apply_relocate_add() function in the module loader to write relocations instead of duplicating functionality in livepatch's arch-dependent klp_write_module_reloc() function. In order to accomplish this, livepatch modules manage their own relocation sections (marked with the SHF_RELA_LIVEPATCH section flag) and livepatch-specific symbols (marked with SHN_LIVEPATCH symbol section index). To apply livepatch relocation sections, livepatch symbols referenced by relocs are resolved and then apply_relocate_add() is called to apply those relocations. In addition, remove x86 livepatch relocation code and the s390 klp_write_module_reloc() function stub. They are no longer needed since relocation work has been offloaded to module loader. Lastly, mark the module as a livepatch module so that the module loader canappropriately identify and initialize it. Signed-off-by: Jessica Yu <jeyu@redhat.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # for s390 changes Signed-off-by: Jiri Kosina <jkosina@suse.cz>
129 lines
3.7 KiB
C
129 lines
3.7 KiB
C
/*
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* livepatch.h - Kernel Live Patching Core
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*
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* Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
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* Copyright (C) 2014 SUSE
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _LINUX_LIVEPATCH_H_
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#define _LINUX_LIVEPATCH_H_
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#include <linux/module.h>
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#include <linux/ftrace.h>
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#if IS_ENABLED(CONFIG_LIVEPATCH)
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#include <asm/livepatch.h>
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enum klp_state {
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KLP_DISABLED,
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KLP_ENABLED
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};
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/**
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* struct klp_func - function structure for live patching
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* @old_name: name of the function to be patched
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* @new_func: pointer to the patched function code
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* @old_sympos: a hint indicating which symbol position the old function
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* can be found (optional)
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* @old_addr: the address of the function being patched
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* @kobj: kobject for sysfs resources
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* @state: tracks function-level patch application state
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* @stack_node: list node for klp_ops func_stack list
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*/
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struct klp_func {
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/* external */
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const char *old_name;
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void *new_func;
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/*
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* The old_sympos field is optional and can be used to resolve
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* duplicate symbol names in livepatch objects. If this field is zero,
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* it is expected the symbol is unique, otherwise patching fails. If
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* this value is greater than zero then that occurrence of the symbol
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* in kallsyms for the given object is used.
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*/
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unsigned long old_sympos;
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/* internal */
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unsigned long old_addr;
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struct kobject kobj;
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enum klp_state state;
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struct list_head stack_node;
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};
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/**
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* struct klp_object - kernel object structure for live patching
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* @name: module name (or NULL for vmlinux)
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* @funcs: function entries for functions to be patched in the object
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* @kobj: kobject for sysfs resources
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* @mod: kernel module associated with the patched object
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* (NULL for vmlinux)
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* @state: tracks object-level patch application state
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*/
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struct klp_object {
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/* external */
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const char *name;
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struct klp_func *funcs;
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/* internal */
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struct kobject kobj;
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struct module *mod;
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enum klp_state state;
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};
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/**
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* struct klp_patch - patch structure for live patching
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* @mod: reference to the live patch module
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* @objs: object entries for kernel objects to be patched
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* @list: list node for global list of registered patches
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* @kobj: kobject for sysfs resources
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* @state: tracks patch-level application state
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*/
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struct klp_patch {
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/* external */
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struct module *mod;
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struct klp_object *objs;
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/* internal */
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struct list_head list;
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struct kobject kobj;
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enum klp_state state;
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};
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#define klp_for_each_object(patch, obj) \
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for (obj = patch->objs; obj->funcs; obj++)
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#define klp_for_each_func(obj, func) \
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for (func = obj->funcs; func->old_name; func++)
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int klp_register_patch(struct klp_patch *);
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int klp_unregister_patch(struct klp_patch *);
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int klp_enable_patch(struct klp_patch *);
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int klp_disable_patch(struct klp_patch *);
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/* Called from the module loader during module coming/going states */
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int klp_module_coming(struct module *mod);
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void klp_module_going(struct module *mod);
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#else /* !CONFIG_LIVEPATCH */
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static inline int klp_module_coming(struct module *mod) { return 0; }
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static inline void klp_module_going(struct module *mod) { }
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#endif /* CONFIG_LIVEPATCH */
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#endif /* _LINUX_LIVEPATCH_H_ */
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