aboutsummaryrefslogtreecommitdiffstats
path: root/payloads/libpayload/libc/malloc.c
blob: 11dfeefadd5ba2157910726e340a3ce7d15ba4c7 (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
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
/*
 * This file is part of the libpayload project.
 *
 * Copyright (C) 2008 Advanced Micro Devices, Inc.
 * Copyright (C) 2008-2010 coresystems GmbH
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * This is a classically weak malloc() implementation. We have a relatively
 * small and static heap, so we take the easy route with an O(N) loop
 * through the tree for every malloc() and free(). Obviously, this doesn't
 * scale past a few hundred KB (if that).
 *
 * We're also susceptible to the usual buffer overrun poisoning, though the
 * risk is within acceptable ranges for this implementation (don't overrun
 * your buffers, kids!).
 */

#define IN_MALLOC_C
#include <libpayload.h>

struct memory_type {
	void *start;
	void *end;
	struct align_region_t* align_regions;
};

extern char _heap, _eheap;	/* Defined in the ldscript. */

static struct memory_type default_type = { (void *)&_heap, (void *)&_eheap, NULL };
static struct memory_type *const heap = &default_type;
static struct memory_type *dma = &default_type;

typedef u64 hdrtype_t;
#define HDRSIZE (sizeof(hdrtype_t))

#define SIZE_BITS ((HDRSIZE << 3) - 7)
#define MAGIC     (((hdrtype_t)0x2a) << (SIZE_BITS + 1))
#define FLAG_FREE (((hdrtype_t)0x01) << (SIZE_BITS + 0))
#define MAX_SIZE  ((((hdrtype_t)0x01) << SIZE_BITS) - 1)

#define SIZE(_h) ((_h) & MAX_SIZE)

#define _HEADER(_s, _f) ((hdrtype_t) (MAGIC | (_f) | ((_s) & MAX_SIZE)))

#define FREE_BLOCK(_s) _HEADER(_s, FLAG_FREE)
#define USED_BLOCK(_s) _HEADER(_s, 0)

#define IS_FREE(_h) (((_h) & (MAGIC | FLAG_FREE)) == (MAGIC | FLAG_FREE))
#define HAS_MAGIC(_h) (((_h) & MAGIC) == MAGIC)

static int free_aligned(void* addr, struct memory_type *type);
void print_malloc_map(void);

#ifdef CONFIG_LP_DEBUG_MALLOC
static int heap_initialized = 0;
static int minimal_free = 0;
#endif

void init_dma_memory(void *start, u32 size)
{
#ifdef CONFIG_LP_DEBUG_MALLOC
	if (dma_initialized()) {
		printf("WARNING: %s called twice!\n");
		return;
	}

	printf("Initializing cache-coherent DMA memory at [%p:%p]\n", start, start + size);
#endif

	dma = malloc(sizeof(*dma));
	dma->start = start;
	dma->end = start + size;
	dma->align_regions = NULL;
}

int dma_initialized()
{
	return dma != heap;
}

/* For boards that don't initialize DMA we assume all locations are coherent */
int dma_coherent(void *ptr)
{
	return !dma_initialized() || (dma->start <= ptr && dma->end > ptr);
}

static void setup(hdrtype_t volatile *start, int size)
{
	*start = FREE_BLOCK(size);

#ifdef CONFIG_LP_DEBUG_MALLOC
	heap_initialized = 1;
	minimal_free  = size;
#endif
}

static void *alloc(int len, struct memory_type *type)
{
	hdrtype_t header;
	hdrtype_t volatile *ptr = (hdrtype_t volatile *)type->start;

	/* Align the size. */
	len = (len + HDRSIZE - 1) & ~(HDRSIZE - 1);

	if (!len || len > MAX_SIZE)
		return (void *)NULL;

	/* Make sure the region is setup correctly. */
	if (!HAS_MAGIC(*ptr))
		setup(ptr, (int)((type->end - type->start) - HDRSIZE));

	/* Find some free space. */
	do {
		header = *ptr;
		int size = SIZE(header);

		if (!HAS_MAGIC(header) || size == 0) {
			printf("memory allocator panic. (%s%s)\n",
			       !HAS_MAGIC(header) ? " no magic " : "",
				   size == 0 ? " size=0 " : "");
			halt();
		}

		if (header & FLAG_FREE) {
			if (len <= size) {
				hdrtype_t volatile *nptr = (hdrtype_t volatile *)((int)ptr + HDRSIZE + len);
				int nsize = size - (HDRSIZE + len);

				/* If there is still room in this block,
				 * then mark it as such otherwise account
				 * the whole space for that block.
				 */

				if (nsize > 0) {
					/* Mark the block as used. */
					*ptr = USED_BLOCK(len);

					/* Create a new free block. */
					*nptr = FREE_BLOCK(nsize);
				} else {
					/* Mark the block as used. */
					*ptr = USED_BLOCK(size);
				}

				return (void *)((int)ptr + HDRSIZE);
			}
		}

		ptr = (hdrtype_t volatile *)((int)ptr + HDRSIZE + size);

	} while (ptr < (hdrtype_t *) type->end);

	/* Nothing available. */
	return (void *)NULL;
}

static void _consolidate(struct memory_type *type)
{
	void *ptr = type->start;

	while (ptr < type->end) {
		void *nptr;
		hdrtype_t hdr = *((hdrtype_t *) ptr);
		unsigned int size = 0;

		if (!IS_FREE(hdr)) {
			ptr += HDRSIZE + SIZE(hdr);
			continue;
		}

		size = SIZE(hdr);
		nptr = ptr + HDRSIZE + SIZE(hdr);

		while (nptr < type->end) {
			hdrtype_t nhdr = *((hdrtype_t *) nptr);

			if (!(IS_FREE(nhdr)))
				break;

			size += SIZE(nhdr) + HDRSIZE;

			*((hdrtype_t *) nptr) = 0;

			nptr += (HDRSIZE + SIZE(nhdr));
		}

		*((hdrtype_t *) ptr) = FREE_BLOCK(size);
		ptr = nptr;
	}
}

void free(void *ptr)
{
	hdrtype_t hdr;
	struct memory_type *type = heap;

	/* Sanity check. */
	if (ptr < type->start || ptr >= type->end) {
		type = dma;
		if (ptr < type->start || ptr >= type->end)
			return;
	}

	if (free_aligned(ptr, type)) return;

	ptr -= HDRSIZE;
	hdr = *((hdrtype_t *) ptr);

	/* Not our header (we're probably poisoned). */
	if (!HAS_MAGIC(hdr))
		return;

	/* Double free. */
	if (hdr & FLAG_FREE)
		return;

	*((hdrtype_t *) ptr) = FREE_BLOCK(SIZE(hdr));
	_consolidate(type);
}

void *malloc(size_t size)
{
	return alloc(size, heap);
}

void *dma_malloc(size_t size)
{
	return alloc(size, dma);
}

void *calloc(size_t nmemb, size_t size)
{
	size_t total = nmemb * size;
	void *ptr = alloc(total, heap);

	if (ptr)
		memset(ptr, 0, total);

	return ptr;
}

void *realloc(void *ptr, size_t size)
{
	void *ret, *pptr;
	unsigned int osize;
	struct memory_type *type = heap;

	if (ptr == NULL)
		return alloc(size, type);

	pptr = ptr - HDRSIZE;

	if (!HAS_MAGIC(*((hdrtype_t *) pptr)))
		return NULL;

	if (ptr < type->start || ptr >= type->end)
		type = dma;

	/* Get the original size of the block. */
	osize = SIZE(*((hdrtype_t *) pptr));

	/*
	 * Free the memory to update the tables - this won't touch the actual
	 * memory, so we can still use it for the copy after we have
	 * reallocated the new space.
	 */
	free(ptr);
	ret = alloc(size, type);

	/*
	 * if ret == NULL, then doh - failure.
	 * if ret == ptr then woo-hoo! no copy needed.
	 */
	if (ret == NULL || ret == ptr)
		return ret;

	/* Copy the memory to the new location. */
	memcpy(ret, ptr, osize > size ? size : osize);

	return ret;
}

struct align_region_t
{
	int alignment;
	/* start in memory, and size in bytes */
	void* start;
	int size;
	/* layout within a region:
	  - num_elements bytes, 0: free, 1: used, 2: used, combines with next
	  - padding to alignment
	  - data section
	  - waste space

	  start_data points to the start of the data section
	*/
	void* start_data;
	/* number of free blocks sized "alignment" */
	int free;
	struct align_region_t *next;
};

static struct align_region_t *allocate_region(int alignment, int num_elements, struct memory_type *type)
{
	struct align_region_t *new_region;
#ifdef CONFIG_LP_DEBUG_MALLOC
	printf("%s(old align_regions=%p, alignment=%u, num_elements=%u)\n",
			__func__, type->align_regions, alignment, num_elements);
#endif

	new_region = malloc(sizeof(struct align_region_t));

	if (!new_region)
		return NULL;
	new_region->alignment = alignment;
	new_region->start = alloc((num_elements+1) * alignment + num_elements, type);
	if (!new_region->start) {
		free(new_region);
		return NULL;
	}
	new_region->start_data = (void*)((u32)(new_region->start + num_elements + alignment - 1) & (~(alignment-1)));
	new_region->size = num_elements * alignment;
	new_region->free = num_elements;
	new_region->next = type->align_regions;
	memset(new_region->start, 0, num_elements);
	type->align_regions = new_region;
	return new_region;
}


static int free_aligned(void* addr, struct memory_type *type)
{
	struct align_region_t *reg = type->align_regions;
	while (reg != 0)
	{
		if ((addr >= reg->start_data) && (addr < reg->start_data + reg->size))
		{
			int i = (addr-reg->start_data)/reg->alignment;
			while (((u8*)reg->start)[i]==2)
			{
				((u8*)reg->start)[i++]=0;
				reg->free++;
			}
			((u8*)reg->start)[i]=0;
			reg->free++;
			return 1;
		}
		reg = reg->next;
	}
	return 0;
}

static void *alloc_aligned(size_t align, size_t size, struct memory_type *type)
{
	if (size == 0) return 0;
	if (type->align_regions == 0) {
		type->align_regions = malloc(sizeof(struct align_region_t));
		if (type->align_regions == NULL)
			return NULL;
		memset(type->align_regions, 0, sizeof(struct align_region_t));
	}
	struct align_region_t *reg = type->align_regions;
look_further:
	while (reg != 0)
	{
		if ((reg->alignment == align) && (reg->free >= (size + align - 1)/align))
		{
#ifdef CONFIG_LP_DEBUG_MALLOC
			printf("  found memalign region. %x free, %x required\n", reg->free, (size + align - 1)/align);
#endif
			break;
		}
		reg = reg->next;
	}
	if (reg == 0)
	{
#ifdef CONFIG_LP_DEBUG_MALLOC
		printf("  need to allocate a new memalign region\n");
#endif
		/* get align regions */
		reg = allocate_region(align, (size<1024)?(1024/align):(((size-1)/align)+1), type);
#ifdef CONFIG_LP_DEBUG_MALLOC
		printf("  ... returned %p\n", reg);
#endif
	}
	if (reg == 0) {
		/* Nothing available. */
		return (void *)NULL;
	}

	int i, count = 0, target = (size+align-1)/align;
	for (i = 0; i < (reg->size/align); i++)
	{
		if (((u8*)reg->start)[i] == 0)
		{
			count++;
			if (count == target) {
				count = i+1-count;
				for (i=0; i<target-1; i++)
				{
					((u8*)reg->start)[count+i]=2;
				}
				((u8*)reg->start)[count+target-1]=1;
				reg->free -= target;
				return reg->start_data+(align*count);
			}
		} else {
			count = 0;
		}
	}
	/* The free space in this region is fragmented,
	   so we will move on and try the next one: */
	reg = reg->next;
	goto look_further; // end condition is once a new region is allocated - it always has enough space
}

void *memalign(size_t align, size_t size)
{
	return alloc_aligned(align, size, heap);
}

void *dma_memalign(size_t align, size_t size)
{
	return alloc_aligned(align, size, dma);
}

/* This is for debugging purposes. */
#ifdef CONFIG_LP_DEBUG_MALLOC
void print_malloc_map(void)
{
	void *ptr = heap->start;
	int free_memory = 0;

	while (ptr < heap->end) {
		hdrtype_t hdr = *((hdrtype_t *) ptr);

		if (!HAS_MAGIC(hdr)) {
			if (heap_initialized)
				printf("Poisoned magic - we're toast\n");
			else
				printf("No magic yet - going to initialize\n");
			break;
		}

		/* FIXME: Verify the size of the block. */

		printf("%x: %s (%x bytes)\n",
		       (unsigned int)(ptr - heap->start),
		       hdr & FLAG_FREE ? "FREE" : "USED", SIZE(hdr));

		if (hdr & FLAG_FREE)
			free_memory += SIZE(hdr);

		ptr += HDRSIZE + SIZE(hdr);
	}

	if (free_memory && (minimal_free > free_memory))
		minimal_free = free_memory;
	printf("Maximum memory consumption: %d bytes\n",
		(unsigned int)(heap->end - heap->start) - HDRSIZE - minimal_free);
}
#endif