v4.19.13 snapshot.
diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
new file mode 100644
index 0000000..aec44b1
--- /dev/null
+++ b/include/linux/livepatch.h
@@ -0,0 +1,214 @@
+/*
+ * 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>
+#include <linux/completion.h>
+
+#if IS_ENABLED(CONFIG_LIVEPATCH)
+
+#include <asm/livepatch.h>
+
+/* task patch states */
+#define KLP_UNDEFINED -1
+#define KLP_UNPATCHED 0
+#define KLP_PATCHED 1
+
+/**
+ * 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
+ * @stack_node: list node for klp_ops func_stack list
+ * @old_size: size of the old function
+ * @new_size: size of the new function
+ * @patched: the func has been added to the klp_ops list
+ * @transition: the func is currently being applied or reverted
+ *
+ * The patched and transition variables define the func's patching state. When
+ * patching, a func is always in one of the following states:
+ *
+ * patched=0 transition=0: unpatched
+ * patched=0 transition=1: unpatched, temporary starting state
+ * patched=1 transition=1: patched, may be visible to some tasks
+ * patched=1 transition=0: patched, visible to all tasks
+ *
+ * And when unpatching, it goes in the reverse order:
+ *
+ * patched=1 transition=0: patched, visible to all tasks
+ * patched=1 transition=1: patched, may be visible to some tasks
+ * patched=0 transition=1: unpatched, temporary ending state
+ * patched=0 transition=0: unpatched
+ */
+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;
+ struct list_head stack_node;
+ unsigned long old_size, new_size;
+ bool patched;
+ bool transition;
+};
+
+struct klp_object;
+
+/**
+ * struct klp_callbacks - pre/post live-(un)patch callback structure
+ * @pre_patch: executed before code patching
+ * @post_patch: executed after code patching
+ * @pre_unpatch: executed before code unpatching
+ * @post_unpatch: executed after code unpatching
+ * @post_unpatch_enabled: flag indicating if post-unpatch callback
+ * should run
+ *
+ * All callbacks are optional. Only the pre-patch callback, if provided,
+ * will be unconditionally executed. If the parent klp_object fails to
+ * patch for any reason, including a non-zero error status returned from
+ * the pre-patch callback, no further callbacks will be executed.
+ */
+struct klp_callbacks {
+ int (*pre_patch)(struct klp_object *obj);
+ void (*post_patch)(struct klp_object *obj);
+ void (*pre_unpatch)(struct klp_object *obj);
+ void (*post_unpatch)(struct klp_object *obj);
+ bool post_unpatch_enabled;
+};
+
+/**
+ * struct klp_object - kernel object structure for live patching
+ * @name: module name (or NULL for vmlinux)
+ * @funcs: function entries for functions to be patched in the object
+ * @callbacks: functions to be executed pre/post (un)patching
+ * @kobj: kobject for sysfs resources
+ * @mod: kernel module associated with the patched object
+ * (NULL for vmlinux)
+ * @patched: the object's funcs have been added to the klp_ops list
+ */
+struct klp_object {
+ /* external */
+ const char *name;
+ struct klp_func *funcs;
+ struct klp_callbacks callbacks;
+
+ /* internal */
+ struct kobject kobj;
+ struct module *mod;
+ bool patched;
+};
+
+/**
+ * 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
+ * @enabled: the patch is enabled (but operation may be incomplete)
+ * @finish: for waiting till it is safe to remove the patch module
+ */
+struct klp_patch {
+ /* external */
+ struct module *mod;
+ struct klp_object *objs;
+
+ /* internal */
+ struct list_head list;
+ struct kobject kobj;
+ bool enabled;
+ struct completion finish;
+};
+
+#define klp_for_each_object(patch, obj) \
+ for (obj = patch->objs; obj->funcs || obj->name; obj++)
+
+#define klp_for_each_func(obj, func) \
+ for (func = obj->funcs; \
+ func->old_name || func->new_func || func->old_sympos; \
+ 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 *);
+
+void arch_klp_init_object_loaded(struct klp_patch *patch,
+ struct klp_object *obj);
+
+/* Called from the module loader during module coming/going states */
+int klp_module_coming(struct module *mod);
+void klp_module_going(struct module *mod);
+
+void klp_copy_process(struct task_struct *child);
+void klp_update_patch_state(struct task_struct *task);
+
+static inline bool klp_patch_pending(struct task_struct *task)
+{
+ return test_tsk_thread_flag(task, TIF_PATCH_PENDING);
+}
+
+static inline bool klp_have_reliable_stack(void)
+{
+ return IS_ENABLED(CONFIG_STACKTRACE) &&
+ IS_ENABLED(CONFIG_HAVE_RELIABLE_STACKTRACE);
+}
+
+typedef int (*klp_shadow_ctor_t)(void *obj,
+ void *shadow_data,
+ void *ctor_data);
+typedef void (*klp_shadow_dtor_t)(void *obj, void *shadow_data);
+
+void *klp_shadow_get(void *obj, unsigned long id);
+void *klp_shadow_alloc(void *obj, unsigned long id,
+ size_t size, gfp_t gfp_flags,
+ klp_shadow_ctor_t ctor, void *ctor_data);
+void *klp_shadow_get_or_alloc(void *obj, unsigned long id,
+ size_t size, gfp_t gfp_flags,
+ klp_shadow_ctor_t ctor, void *ctor_data);
+void klp_shadow_free(void *obj, unsigned long id, klp_shadow_dtor_t dtor);
+void klp_shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor);
+
+#else /* !CONFIG_LIVEPATCH */
+
+static inline int klp_module_coming(struct module *mod) { return 0; }
+static inline void klp_module_going(struct module *mod) {}
+static inline bool klp_patch_pending(struct task_struct *task) { return false; }
+static inline void klp_update_patch_state(struct task_struct *task) {}
+static inline void klp_copy_process(struct task_struct *child) {}
+
+#endif /* CONFIG_LIVEPATCH */
+
+#endif /* _LINUX_LIVEPATCH_H_ */