kpatch/kmod/core/kpatch.h
Josh Poimboeuf 84c34ff584 implement per-object patching/relocations
The recent module patching code has exposed some problems with our data
structures. We currently patch the funcs and dynrelas individually,
which is kind of scary now that different objects can be patched at
different times.  Instead it's cleaner and safer to group them by
patched object.

This patch implements per-object patching and relocations by refactoring
the interfaces:

- Completely separate the create-diff-object <-> patch module interface
  from the patch module <-> core module interface. create-diff-object
  will include "kpatch-patch.h" but not "kpatch.h". Thus,
  create-diff-object has no knowledge about the core module's
  interfaces, and the core module has no knowledge about the patch
  module's special sections.

- Newly added kpatch-patch.h defines the format of the patch module
  special sections. It's used by create-diff-object to create the
  special sections and used by the patch module to read them.

- kpatch.h still defines the core module interfaces. Each kpatch_module
  has a list of kpatch_objects for each module object to be patched.
  Each kpatch_object has a list of kpatch_funcs and a list of
  kpatch_dynrelas. The patch module creates these lists when populating
  kpatch_module.

This way of structuring the data allows us to patch funcs and dynrelas
on a per patched object basis, which will allow us to catch more error
scenarios and make the code easier to manage going forward.  It also
allows the use of much more common code between kpatch_register() and
kpatch_module_notify().
2014-06-17 10:03:08 -05:00

88 lines
2.0 KiB
C

/*
* kpatch.h
*
* Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
* Copyright (C) 2013-2014 Josh Poimboeuf <jpoimboe@redhat.com>
*
* 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 <https://www.gnu.org/licenses/>.
*
* Contains the API for the core kpatch module used by the patch modules
*/
#ifndef _KPATCH_H_
#define _KPATCH_H_
#include <linux/types.h>
#include <linux/module.h>
enum kpatch_op {
KPATCH_OP_NONE,
KPATCH_OP_PATCH,
KPATCH_OP_UNPATCH,
};
struct kpatch_func {
/* public */
unsigned long new_addr;
unsigned long new_size;
unsigned long old_offset;
unsigned long old_size;
const char *name;
struct list_head list;
/* private */
struct hlist_node node;
unsigned long old_addr;
enum kpatch_op op;
};
struct kpatch_dynrela {
unsigned long dest;
unsigned long src;
unsigned long type;
const char *name;
const char *objname;
int addend;
struct list_head list;
};
struct kpatch_object {
struct list_head list;
const char *name;
struct list_head funcs;
struct list_head dynrelas;
/* private */
struct module *mod;
};
struct kpatch_module {
/* public */
struct module *mod;
struct list_head objects;
/* public read-only */
bool enabled;
/* private */
struct list_head list;
};
extern struct kobject *kpatch_patches_kobj;
extern int kpatch_register(struct kpatch_module *kpmod, bool replace);
extern int kpatch_unregister(struct kpatch_module *kpmod);
#endif /* _KPATCH_H_ */