cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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chipreg.c (2328B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Registration for chip drivers
      4 *
      5 */
      6
      7#include <linux/kernel.h>
      8#include <linux/module.h>
      9#include <linux/kmod.h>
     10#include <linux/spinlock.h>
     11#include <linux/slab.h>
     12#include <linux/mtd/map.h>
     13#include <linux/mtd/mtd.h>
     14
     15static DEFINE_SPINLOCK(chip_drvs_lock);
     16static LIST_HEAD(chip_drvs_list);
     17
     18void register_mtd_chip_driver(struct mtd_chip_driver *drv)
     19{
     20	spin_lock(&chip_drvs_lock);
     21	list_add(&drv->list, &chip_drvs_list);
     22	spin_unlock(&chip_drvs_lock);
     23}
     24
     25void unregister_mtd_chip_driver(struct mtd_chip_driver *drv)
     26{
     27	spin_lock(&chip_drvs_lock);
     28	list_del(&drv->list);
     29	spin_unlock(&chip_drvs_lock);
     30}
     31
     32static struct mtd_chip_driver *get_mtd_chip_driver (const char *name)
     33{
     34	struct mtd_chip_driver *ret = NULL, *this;
     35
     36	spin_lock(&chip_drvs_lock);
     37
     38	list_for_each_entry(this, &chip_drvs_list, list) {
     39		if (!strcmp(this->name, name)) {
     40			ret = this;
     41			break;
     42		}
     43	}
     44	if (ret && !try_module_get(ret->module))
     45		ret = NULL;
     46
     47	spin_unlock(&chip_drvs_lock);
     48
     49	return ret;
     50}
     51
     52	/* Hide all the horrid details, like some silly person taking
     53	   get_module_symbol() away from us, from the caller. */
     54
     55struct mtd_info *do_map_probe(const char *name, struct map_info *map)
     56{
     57	struct mtd_chip_driver *drv;
     58	struct mtd_info *ret;
     59
     60	drv = get_mtd_chip_driver(name);
     61
     62	if (!drv && !request_module("%s", name))
     63		drv = get_mtd_chip_driver(name);
     64
     65	if (!drv)
     66		return NULL;
     67
     68	ret = drv->probe(map);
     69
     70	/* We decrease the use count here. It may have been a
     71	   probe-only module, which is no longer required from this
     72	   point, having given us a handle on (and increased the use
     73	   count of) the actual driver code.
     74	*/
     75	module_put(drv->module);
     76
     77	return ret;
     78}
     79/*
     80 * Destroy an MTD device which was created for a map device.
     81 * Make sure the MTD device is already unregistered before calling this
     82 */
     83void map_destroy(struct mtd_info *mtd)
     84{
     85	struct map_info *map = mtd->priv;
     86
     87	if (map->fldrv->destroy)
     88		map->fldrv->destroy(mtd);
     89
     90	module_put(map->fldrv->module);
     91
     92	kfree(mtd);
     93}
     94
     95EXPORT_SYMBOL(register_mtd_chip_driver);
     96EXPORT_SYMBOL(unregister_mtd_chip_driver);
     97EXPORT_SYMBOL(do_map_probe);
     98EXPORT_SYMBOL(map_destroy);
     99
    100MODULE_LICENSE("GPL");
    101MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
    102MODULE_DESCRIPTION("Core routines for registering and invoking MTD chip drivers");