Commit 20e55025 authored by Jason Baron's avatar Jason Baron Committed by Jiri Kosina
Browse files

livepatch: Use lists to manage patches, objects and functions 



Currently klp_patch contains a pointer to a statically allocated array of
struct klp_object and struct klp_objects contains a pointer to a statically
allocated array of klp_func. In order to allow for the dynamic allocation
of objects and functions, link klp_patch, klp_object, and klp_func together
via linked lists. This allows us to more easily allocate new objects and
functions, while having the iterator be a simple linked list walk.

The static structures are added to the lists early. It allows to add
the dynamically allocated objects before klp_init_object() and
klp_init_func() calls. Therefore it reduces the further changes
to the code.

This patch does not change the existing behavior.

Signed-off-by: default avatarJason Baron <jbaron@akamai.com>
[pmladek@suse.com: Initialize lists before init calls]
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
Acked-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 958ef1e3

include/linux/livepatch.h

+17 −2
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/module.h>

#include <linux/ftrace.h>

#include <linux/completion.h>

#include <linux/list.h>



#if IS_ENABLED(CONFIG_LIVEPATCH)
@@ -42,6 +43,7 @@ 
 *		can be found (optional)

 * @old_func:	pointer to the function being patched

 * @kobj:	kobject for sysfs resources

 * @node:	list node for klp_object func_list

 * @stack_node:	list node for klp_ops func_stack list

 * @old_size:	size of the old function

 * @new_size:	size of the new function
@@ -80,6 +82,7 @@ struct klp_func { 
	/* internal */

	void *old_func;

	struct kobject kobj;

	struct list_head node;

	struct list_head stack_node;

	unsigned long old_size, new_size;

	bool kobj_added;
@@ -117,6 +120,8 @@ struct klp_callbacks { 
 * @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

 * @func_list:	dynamic list of the function entries

 * @node:	list node for klp_patch obj_list

 * @mod:	kernel module associated with the patched object

 *		(NULL for vmlinux)

 * @kobj_added: @kobj has been added and needs freeing
@@ -130,6 +135,8 @@ struct klp_object { 


	/* internal */

	struct kobject kobj;

	struct list_head func_list;

	struct list_head node;

	struct module *mod;

	bool kobj_added;

	bool patched;
@@ -141,6 +148,7 @@ struct klp_object { 
 * @objs:	object entries for kernel objects to be patched

 * @list:	list node for global list of actively used patches

 * @kobj:	kobject for sysfs resources

 * @obj_list:	dynamic list of the object entries

 * @kobj_added: @kobj has been added and needs freeing

 * @enabled:	the patch is enabled (but operation may be incomplete)

 * @forced:	was involved in a forced transition
@@ -155,6 +163,7 @@ struct klp_patch { 
	/* internal */

	struct list_head list;

	struct kobject kobj;

	struct list_head obj_list;

	bool kobj_added;

	bool enabled;

	bool forced;
@@ -162,14 +171,20 @@ struct klp_patch { 
	struct completion finish;

};



#define klp_for_each_object(patch, obj) \

#define klp_for_each_object_static(patch, obj) \

	for (obj = patch->objs; obj->funcs || obj->name; obj++)



#define klp_for_each_func(obj, func) \

#define klp_for_each_object(patch, obj)	\

	list_for_each_entry(obj, &patch->obj_list, node)



#define klp_for_each_func_static(obj, func) \

	for (func = obj->funcs; \

	     func->old_name || func->new_func || func->old_sympos; \

	     func++)



#define klp_for_each_func(obj, func)	\

	list_for_each_entry(func, &obj->func_list, node)



int klp_enable_patch(struct klp_patch *);



void arch_klp_init_object_loaded(struct klp_patch *patch,

kernel/livepatch/core.c

+7 −2
Original line number Diff line number Diff line
@@ -659,20 +659,25 @@ static int klp_init_patch_early(struct klp_patch *patch) 
		return -EINVAL;



	INIT_LIST_HEAD(&patch->list);

	INIT_LIST_HEAD(&patch->obj_list);

	patch->kobj_added = false;

	patch->enabled = false;

	patch->forced = false;

	INIT_WORK(&patch->free_work, klp_free_patch_work_fn);

	init_completion(&patch->finish);



	klp_for_each_object(patch, obj) {

	klp_for_each_object_static(patch, obj) {

		if (!obj->funcs)

			return -EINVAL;



		INIT_LIST_HEAD(&obj->func_list);

		obj->kobj_added = false;

		list_add_tail(&obj->node, &patch->obj_list);



		klp_for_each_func(obj, func)

		klp_for_each_func_static(obj, func) {

			func->kobj_added = false;

			list_add_tail(&func->node, &obj->func_list);

		}

	}



	if (!try_module_get(patch->mod))

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