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/*
* Kernel Probes (KProbes)
* kernel/kprobes.c
*
* 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2002, 2004
*/
/*
* Dynamic Binary Instrumentation Module based on KProbes
* modules/kprobe/swap_slots.c
*
* 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) Samsung Electronics, 2006-2012
*
* 2008-2009 Alexey Gerenkov <a.gerenkov@samsung.com> User-Space
* Probes initial implementation; Support x86/ARM/MIPS for both user and kernel spaces.
* 2010 Ekaterina Gorelkina <e.gorelkina@samsung.com>: redesign module for separating core and arch parts
* 2012-2013 Vyacheslav Cherkashin <v.cherkashin@samsung.com> new memory allocator for slots
*/
#include <linux/module.h>
#include <linux/rculist.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include "swap_slots.h"
#include "dbi_kprobes_deps.h"
struct chunk {
unsigned long *data;
unsigned long first_available;
unsigned long count_available;
spinlock_t lock;
unsigned long size;
unsigned long *index;
};
struct fixed_alloc
{
struct hlist_node hlist;
struct chunk chunk;
};
static void chunk_init(struct chunk *chunk, void *data, size_t size, size_t size_block)
{
unsigned long i;
unsigned long *p;
spin_lock_init(&chunk->lock);
chunk->data = (unsigned long *)data;
chunk->first_available = 0;
chunk->count_available = size / size_block;
chunk->size = chunk->count_available;
chunk->index = kmalloc(sizeof(*chunk->index)*chunk->count_available, GFP_ATOMIC);
p = chunk->index;
for (i = 0; i != chunk->count_available; ++p) {
*p = ++i;
}
}
static void chunk_uninit(struct chunk *chunk)
{
kfree(chunk->index);
}
static void* chunk_allocate(struct chunk *chunk, size_t size_block)
{
unsigned long *ret;
if (!chunk->count_available) {
return NULL;
}
spin_lock(&chunk->lock);
ret = chunk->data + chunk->first_available*size_block;
chunk->first_available = chunk->index[chunk->first_available];
--chunk->count_available;
spin_unlock(&chunk->lock);
return ret;
}
static void chunk_deallocate(struct chunk *chunk, void *p, size_t size_block)
{
unsigned long idx = ((unsigned long *)p - chunk->data)/size_block;
spin_lock(&chunk->lock);
chunk->index[idx] = chunk->first_available;
chunk->first_available = idx;
++chunk->count_available;
spin_unlock(&chunk->lock);
}
static inline int chunk_check_ptr(struct chunk *chunk, void *p, size_t size)
{
if (( chunk->data <= (unsigned long *)p) &&
((chunk->data + size/sizeof(chunk->data)) > (unsigned long *)p)) {
return 1;
}
return 0;
}
static inline int chunk_free(struct chunk *chunk)
{
return (chunk->count_available == chunk->size);
}
static struct fixed_alloc *create_fixed_alloc(struct slot_manager *sm)
{
void *data;
struct fixed_alloc *fa;
fa = kmalloc(sizeof(*fa), GFP_ATOMIC);
if (fa == NULL) {
return NULL;
}
data = sm->alloc(sm);
if(data == NULL) {
kfree(fa);
return NULL;
}
chunk_init(&fa->chunk, data, PAGE_SIZE/sizeof(unsigned long), sm->slot_size);
return fa;
}
static void free_fixed_alloc(struct slot_manager *sm, struct fixed_alloc *fa)
{
chunk_uninit(&fa->chunk);
sm->free(sm, fa->chunk.data);
kfree(fa);
}
void *swap_slot_alloc(struct slot_manager *sm)
{
void *free_slot;
struct fixed_alloc *fa;
DECLARE_NODE_PTR_FOR_HLIST(pos);
swap_hlist_for_each_entry_rcu(fa, pos, &sm->page_list, hlist) {
free_slot = chunk_allocate(&fa->chunk, sm->slot_size);
if (free_slot)
return free_slot;
}
fa = create_fixed_alloc(sm);
if(fa == NULL)
return NULL;
INIT_HLIST_NODE(&fa->hlist);
hlist_add_head_rcu(&fa->hlist, &sm->page_list);
return chunk_allocate(&fa->chunk, sm->slot_size);
}
EXPORT_SYMBOL_GPL(swap_slot_alloc);
void swap_slot_free(struct slot_manager *sm, void *slot)
{
struct fixed_alloc *fa;
DECLARE_NODE_PTR_FOR_HLIST(pos);
if (slot == NULL)
return;
swap_hlist_for_each_entry_rcu(fa, pos, &sm->page_list, hlist) {
if (!chunk_check_ptr(&fa->chunk, slot, PAGE_SIZE))
continue;
chunk_deallocate(&fa->chunk, slot, sm->slot_size);
if (chunk_free(&fa->chunk)) {
hlist_del_rcu(&fa->hlist);
free_fixed_alloc(sm, fa);
}
return;
}
panic("%s: slot=%p is not data base\n", __func__, slot);
}
EXPORT_SYMBOL_GPL(swap_slot_free);
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