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/*
* Copyright (C) 2010-2011, 2013-2014 ARM Limited. All rights reserved.
*
* This program is free software and is provided to you under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation, and any use by you of this program is subject to the terms of such GNU licence.
*
* A copy of the licence is included with the program, and can also be obtained from Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "mali_kernel_common.h"
#include "mali_osk.h"
#include "ump_osk.h"
#include "ump_kernel_common.h"
#include "ump_kernel_types.h"
#include "ump_kernel_random_mapping.h"
#include <linux/random.h>
#include <linux/rbtree.h>
#include <linux/sched.h>
#include <linux/jiffies.h>
static ump_dd_mem *search(struct rb_root *root, int id)
{
struct rb_node *node = root->rb_node;
while (node) {
ump_dd_mem *e = container_of(node, ump_dd_mem, node);
if (id < e->secure_id) {
node = node->rb_left;
} else if (id > e->secure_id) {
node = node->rb_right;
} else {
return e;
}
}
return NULL;
}
static mali_bool insert(struct rb_root *root, int id, ump_dd_mem *mem)
{
struct rb_node **new = &(root->rb_node);
struct rb_node *parent = NULL;
while (*new) {
ump_dd_mem *this = container_of(*new, ump_dd_mem, node);
parent = *new;
if (id < this->secure_id) {
new = &((*new)->rb_left);
} else if (id > this->secure_id) {
new = &((*new)->rb_right);
} else {
printk(KERN_ERR "UMP: ID already used %x\n", id);
return MALI_FALSE;
}
}
rb_link_node(&mem->node, parent, new);
rb_insert_color(&mem->node, root);
return MALI_TRUE;
}
ump_random_mapping *ump_random_mapping_create(void)
{
ump_random_mapping *map = _mali_osk_calloc(1, sizeof(ump_random_mapping));
if (NULL == map)
return NULL;
map->lock = _mali_osk_mutex_rw_init(_MALI_OSK_LOCKFLAG_ORDERED,
_MALI_OSK_LOCK_ORDER_DESCRIPTOR_MAP);
if (NULL != map->lock) {
map->root = RB_ROOT;
#if UMP_RANDOM_MAP_DELAY
map->failed.count = 0;
map->failed.timestamp = jiffies;
#endif
return map;
}
return NULL;
}
void ump_random_mapping_destroy(ump_random_mapping *map)
{
_mali_osk_mutex_rw_term(map->lock);
_mali_osk_free(map);
}
int ump_random_mapping_insert(ump_random_mapping *map, ump_dd_mem *mem)
{
_mali_osk_mutex_rw_wait(map->lock, _MALI_OSK_LOCKMODE_RW);
while (1) {
u32 id;
get_random_bytes(&id, sizeof(id));
/* Try a new random number if id happened to be the invalid
* secure ID (-1). */
if (unlikely(id == UMP_INVALID_SECURE_ID))
continue;
/* Insert into the tree. If the id was already in use, get a
* new random id and try again. */
if (insert(&map->root, id, mem)) {
mem->secure_id = id;
break;
}
}
_mali_osk_mutex_rw_signal(map->lock, _MALI_OSK_LOCKMODE_RW);
return 0;
}
ump_dd_mem *ump_random_mapping_get(ump_random_mapping *map, int id)
{
ump_dd_mem *mem = NULL;
#if UMP_RANDOM_MAP_DELAY
int do_delay = 0;
#endif
DEBUG_ASSERT(map);
_mali_osk_mutex_rw_wait(map->lock, _MALI_OSK_LOCKMODE_RO);
mem = search(&map->root, id);
if (unlikely(NULL == mem)) {
#if UMP_RANDOM_MAP_DELAY
map->failed.count++;
if (time_is_before_jiffies(map->failed.timestamp +
UMP_FAILED_LOOKUP_DELAY * HZ)) {
/* If it is a long time since last failure, reset
* the counter and skip the delay this time. */
map->failed.count = 0;
} else if (map->failed.count > UMP_FAILED_LOOKUPS_ALLOWED) {
do_delay = 1;
}
map->failed.timestamp = jiffies;
#endif /* UMP_RANDOM_MAP_DELAY */
} else {
ump_dd_reference_add(mem);
}
_mali_osk_mutex_rw_signal(map->lock, _MALI_OSK_LOCKMODE_RO);
#if UMP_RANDOM_MAP_DELAY
if (do_delay) {
/* Apply delay */
schedule_timeout_killable(UMP_FAILED_LOOKUP_DELAY);
}
#endif /* UMP_RANDOM_MAP_DELAY */
return mem;
}
static ump_dd_mem *ump_random_mapping_remove_internal(ump_random_mapping *map, int id)
{
ump_dd_mem *mem = NULL;
mem = search(&map->root, id);
if (mem) {
rb_erase(&mem->node, &map->root);
}
return mem;
}
void ump_random_mapping_put(ump_dd_mem *mem)
{
int new_ref;
_mali_osk_mutex_rw_wait(device.secure_id_map->lock, _MALI_OSK_LOCKMODE_RW);
new_ref = _ump_osk_atomic_dec_and_read(&mem->ref_count);
DBG_MSG(5, ("Memory reference decremented. ID: %u, new value: %d\n",
mem->secure_id, new_ref));
if (0 == new_ref) {
DBG_MSG(3, ("Final release of memory. ID: %u\n", mem->secure_id));
ump_random_mapping_remove_internal(device.secure_id_map, mem->secure_id);
mem->release_func(mem->ctx, mem);
_mali_osk_free(mem);
}
_mali_osk_mutex_rw_signal(device.secure_id_map->lock, _MALI_OSK_LOCKMODE_RW);
}
ump_dd_mem *ump_random_mapping_remove(ump_random_mapping *map, int descriptor)
{
ump_dd_mem *mem;
_mali_osk_mutex_rw_wait(map->lock, _MALI_OSK_LOCKMODE_RW);
mem = ump_random_mapping_remove_internal(map, descriptor);
_mali_osk_mutex_rw_signal(map->lock, _MALI_OSK_LOCKMODE_RW);
return mem;
}
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