summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/mm/imalloc.c
blob: add8c1a9af68ae12db88b1501f7b3f5d1c2ad1e4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
/*
 * c 2001 PPC 64 Team, IBM Corp
 * 
 *      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.
 */

#include <linux/slab.h>
#include <linux/vmalloc.h>

#include <asm/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <linux/mutex.h>
#include <asm/cacheflush.h>

#include "mmu_decl.h"

static DEFINE_MUTEX(imlist_mutex);
struct vm_struct * imlist = NULL;

static int get_free_im_addr(unsigned long size, unsigned long *im_addr)
{
	unsigned long addr;
	struct vm_struct **p, *tmp;

	addr = ioremap_bot;
	for (p = &imlist; (tmp = *p) ; p = &tmp->next) {
		if (size + addr < (unsigned long) tmp->addr)
			break;
		if ((unsigned long)tmp->addr >= ioremap_bot)
			addr = tmp->size + (unsigned long) tmp->addr;
		if (addr >= IMALLOC_END-size)
			return 1;
	}
	*im_addr = addr;

	return 0;
}

/* Return whether the region described by v_addr and size is a subset
 * of the region described by parent
 */
static inline int im_region_is_subset(unsigned long v_addr, unsigned long size,
			struct vm_struct *parent)
{
	return (int) (v_addr >= (unsigned long) parent->addr &&
	              v_addr < (unsigned long) parent->addr + parent->size &&
	    	      size < parent->size);
}

/* Return whether the region described by v_addr and size is a superset
 * of the region described by child
 */
static int im_region_is_superset(unsigned long v_addr, unsigned long size,
		struct vm_struct *child)
{
	struct vm_struct parent;

	parent.addr = (void *) v_addr;
	parent.size = size;

	return im_region_is_subset((unsigned long) child->addr, child->size,
			&parent);
}

/* Return whether the region described by v_addr and size overlaps
 * the region described by vm.  Overlapping regions meet the
 * following conditions:
 * 1) The regions share some part of the address space
 * 2) The regions aren't identical
 * 3) Neither region is a subset of the other
 */
static int im_region_overlaps(unsigned long v_addr, unsigned long size,
		     struct vm_struct *vm)
{
	if (im_region_is_superset(v_addr, size, vm))
		return 0;

	return (v_addr + size > (unsigned long) vm->addr + vm->size &&
		v_addr < (unsigned long) vm->addr + vm->size) ||
	       (v_addr < (unsigned long) vm->addr &&
		v_addr + size > (unsigned long) vm->addr);
}

/* Determine imalloc status of region described by v_addr and size.
 * Can return one of the following:
 * IM_REGION_UNUSED   -  Entire region is unallocated in imalloc space.
 * IM_REGION_SUBSET -    Region is a subset of a region that is already
 * 			 allocated in imalloc space.
 * 		         vm will be assigned to a ptr to the parent region.
 * IM_REGION_EXISTS -    Exact region already allocated in imalloc space.
 *                       vm will be assigned to a ptr to the existing imlist
 *                       member.
 * IM_REGION_OVERLAPS -  Region overlaps an allocated region in imalloc space.
 * IM_REGION_SUPERSET -  Region is a superset of a region that is already
 *                       allocated in imalloc space.
 */
static int im_region_status(unsigned long v_addr, unsigned long size,
		    struct vm_struct **vm)
{
	struct vm_struct *tmp;

	for (tmp = imlist; tmp; tmp = tmp->next)
		if (v_addr < (unsigned long) tmp->addr + tmp->size)
			break;

	*vm = NULL;
	if (tmp) {
		if (im_region_overlaps(v_addr, size, tmp))
			return IM_REGION_OVERLAP;

		*vm = tmp;
		if (im_region_is_subset(v_addr, size, tmp)) {
			/* Return with tmp pointing to superset */
			return IM_REGION_SUBSET;
		}
		if (im_region_is_superset(v_addr, size, tmp)) {
			/* Return with tmp pointing to first subset */
			return IM_REGION_SUPERSET;
		}
		else if (v_addr == (unsigned long) tmp->addr &&
		 	 size == tmp->size) {
			/* Return with tmp pointing to exact region */
			return IM_REGION_EXISTS;
		}
	}

	return IM_REGION_UNUSED;
}

static struct vm_struct * split_im_region(unsigned long v_addr, 
		unsigned long size, struct vm_struct *parent)
{
	struct vm_struct *vm1 = NULL;
	struct vm_struct *vm2 = NULL;
	struct vm_struct *new_vm = NULL;
	
	vm1 = (struct vm_struct *) kmalloc(sizeof(*vm1), GFP_KERNEL);
	if (vm1	== NULL) {
		printk(KERN_ERR "%s() out of memory\n", __FUNCTION__);
		return NULL;
	}

	if (v_addr == (unsigned long) parent->addr) {
	        /* Use existing parent vm_struct to represent child, allocate
		 * new one for the remainder of parent range
		 */
		vm1->size = parent->size - size;
		vm1->addr = (void *) (v_addr + size);
		vm1->next = parent->next;

		parent->size = size;
		parent->next = vm1;
		new_vm = parent;
	} else if (v_addr + size == (unsigned long) parent->addr + 
			parent->size) {
		/* Allocate new vm_struct to represent child, use existing
		 * parent one for remainder of parent range
		 */
		vm1->size = size;
		vm1->addr = (void *) v_addr;
		vm1->next = parent->next;
		new_vm = vm1;

		parent->size -= size;
		parent->next = vm1;
	} else {
	        /* Allocate two new vm_structs for the new child and 
		 * uppermost remainder, and use existing parent one for the
		 * lower remainder of parent range
		 */
		vm2 = (struct vm_struct *) kmalloc(sizeof(*vm2), GFP_KERNEL);
		if (vm2 == NULL) {
			printk(KERN_ERR "%s() out of memory\n", __FUNCTION__);
			kfree(vm1);
			return NULL;
		}

		vm1->size = size;
		vm1->addr = (void *) v_addr;
		vm1->next = vm2;
		new_vm = vm1;

		vm2->size = ((unsigned long) parent->addr + parent->size) - 
				(v_addr + size);
		vm2->addr = (void *) v_addr + size;
		vm2->next = parent->next;

		parent->size = v_addr - (unsigned long) parent->addr;
		parent->next = vm1;
	}

	return new_vm;
}

static struct vm_struct * __add_new_im_area(unsigned long req_addr, 
					    unsigned long size)
{
	struct vm_struct **p, *tmp, *area;
		
	for (p = &imlist; (tmp = *p) ; p = &tmp->next) {
		if (req_addr + size <= (unsigned long)tmp->addr)
			break;
	}
	
	area = (struct vm_struct *) kmalloc(sizeof(*area), GFP_KERNEL);
	if (!area)
		return NULL;
	area->flags = 0;
	area->addr = (void *)req_addr;
	area->size = size;
	area->next = *p;
	*p = area;

	return area;
}

static struct vm_struct * __im_get_area(unsigned long req_addr, 
					unsigned long size,
					int criteria)
{
	struct vm_struct *tmp;
	int status;

	status = im_region_status(req_addr, size, &tmp);
	if ((criteria & status) == 0) {
		return NULL;
	}
	
	switch (status) {
	case IM_REGION_UNUSED:
		tmp = __add_new_im_area(req_addr, size);
		break;
	case IM_REGION_SUBSET:
		tmp = split_im_region(req_addr, size, tmp);
		break;
	case IM_REGION_EXISTS:
		/* Return requested region */
		break;
	case IM_REGION_SUPERSET:
		/* Return first existing subset of requested region */
		break;
	default:
		printk(KERN_ERR "%s() unexpected imalloc region status\n",
				__FUNCTION__);
		tmp = NULL;
	}

	return tmp;
}

struct vm_struct * im_get_free_area(unsigned long size)
{
	struct vm_struct *area;
	unsigned long addr;
	
	mutex_lock(&imlist_mutex);
	if (get_free_im_addr(size, &addr)) {
		printk(KERN_ERR "%s() cannot obtain addr for size 0x%lx\n",
				__FUNCTION__, size);
		area = NULL;
		goto next_im_done;
	}

	area = __im_get_area(addr, size, IM_REGION_UNUSED);
	if (area == NULL) {
		printk(KERN_ERR 
		       "%s() cannot obtain area for addr 0x%lx size 0x%lx\n",
			__FUNCTION__, addr, size);
	}
next_im_done:
	mutex_unlock(&imlist_mutex);
	return area;
}

struct vm_struct * im_get_area(unsigned long v_addr, unsigned long size,
		int criteria)
{
	struct vm_struct *area;

	mutex_lock(&imlist_mutex);
	area = __im_get_area(v_addr, size, criteria);
	mutex_unlock(&imlist_mutex);
	return area;
}

void im_free(void * addr)
{
	struct vm_struct **p, *tmp;
  
	if (!addr)
		return;
	if ((unsigned long) addr & ~PAGE_MASK) {
		printk(KERN_ERR "Trying to %s bad address (%p)\n", __FUNCTION__,			addr);
		return;
	}
	mutex_lock(&imlist_mutex);
	for (p = &imlist ; (tmp = *p) ; p = &tmp->next) {
		if (tmp->addr == addr) {
			*p = tmp->next;
			unmap_vm_area(tmp);
			kfree(tmp);
			mutex_unlock(&imlist_mutex);
			return;
		}
	}
	mutex_unlock(&imlist_mutex);
	printk(KERN_ERR "Trying to %s nonexistent area (%p)\n", __FUNCTION__,
			addr);
}