1/*
2 *  linux/mm/bootmem.c
3 *
4 *  Copyright (C) 1999 Ingo Molnar
5 *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
6 *
7 *  simple boot-time physical memory area allocator and
8 *  free memory collector. It's used to deal with reserved
9 *  system memory and memory holes as well.
10 */
11
12#include <linux/mm.h>
13#include <linux/kernel_stat.h>
14#include <linux/swap.h>
15#include <linux/swapctl.h>
16#include <linux/interrupt.h>
17#include <linux/init.h>
18#include <linux/bootmem.h>
19#include <linux/mmzone.h>
20#include <asm/dma.h>
21#include <asm/io.h>
22
23/*
24 * Access to this subsystem has to be serialized externally. (this is
25 * true for the boot process anyway)
26 */
27unsigned long max_low_pfn;
28unsigned long min_low_pfn;
29unsigned long max_pfn;
30
31/* return the number of _pages_ that will be allocated for the boot bitmap */
32unsigned long __init bootmem_bootmap_pages (unsigned long pages)
33{
34	unsigned long mapsize;
35
36	mapsize = (pages+7)/8;
37	mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
38	mapsize >>= PAGE_SHIFT;
39
40	return mapsize;
41}
42
43/*
44 * Called once to set up the allocator itself.
45 */
46static unsigned long __init init_bootmem_core (pg_data_t *pgdat,
47	unsigned long mapstart, unsigned long start, unsigned long end)
48{
49	bootmem_data_t *bdata = pgdat->bdata;
50	unsigned long mapsize = ((end - start)+7)/8;
51
52	pgdat->node_next = pgdat_list;
53	pgdat_list = pgdat;
54
55	mapsize = (mapsize + (sizeof(long) - 1UL)) & ~(sizeof(long) - 1UL);
56	bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
57	bdata->node_boot_start = (start << PAGE_SHIFT);
58	bdata->node_low_pfn = end;
59
60#if	!defined(CONFIG_HWSIM) || defined(CONFIG_HWSIM_ZMEM)
61	/*
62	 * Initially all pages are reserved - setup_arch() has to
63	 * register free RAM areas explicitly.
64	 */
65	memset(bdata->node_bootmem_map, 0xff, mapsize);
66#endif
67
68	return mapsize;
69}
70
71/*
72 * Marks a particular physical memory range as unallocatable. Usable RAM
73 * might be used for boot-time allocations - or it might get added
74 * to the free page pool later on.
75 */
76static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
77{
78	unsigned long i;
79	/*
80	 * round up, partially reserved pages are considered
81	 * fully reserved.
82	 */
83	unsigned long sidx = (addr - bdata->node_boot_start)/PAGE_SIZE;
84	unsigned long eidx = (addr + size - bdata->node_boot_start +
85							PAGE_SIZE-1)/PAGE_SIZE;
86	unsigned long end = (addr + size + PAGE_SIZE-1)/PAGE_SIZE;
87
88	if (!size) BUG();
89
90	if (sidx < 0)
91		BUG();
92	if (eidx < 0)
93		BUG();
94	if (sidx >= eidx)
95		BUG();
96	if ((addr >> PAGE_SHIFT) >= bdata->node_low_pfn)
97		BUG();
98	if (end > bdata->node_low_pfn)
99		BUG();
100	for (i = sidx; i < eidx; i++)
101		if (test_and_set_bit(i, bdata->node_bootmem_map))
102			printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
103}
104
105static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
106{
107	unsigned long i;
108	unsigned long start;
109	/*
110	 * round down end of usable mem, partially free pages are
111	 * considered reserved.
112	 */
113	unsigned long sidx;
114	unsigned long eidx = (addr + size - bdata->node_boot_start)/PAGE_SIZE;
115	unsigned long end = (addr + size)/PAGE_SIZE;
116
117	if (!size) BUG();
118	if (end > bdata->node_low_pfn)
119		BUG();
120
121	/*
122	 * Round up the beginning of the address.
123	 */
124	start = (addr + PAGE_SIZE-1) / PAGE_SIZE;
125	sidx = start - (bdata->node_boot_start/PAGE_SIZE);
126
127	for (i = sidx; i < eidx; i++) {
128		if (!test_and_clear_bit(i, bdata->node_bootmem_map))
129			BUG();
130	}
131}
132
133/*
134 * We 'merge' subsequent allocations to save space. We might 'lose'
135 * some fraction of a page if allocations cannot be satisfied due to
136 * size constraints on boxes where there is physical RAM space
137 * fragmentation - in these cases * (mostly large memory boxes) this
138 * is not a problem.
139 *
140 * On low memory boxes we get it right in 100% of the cases.
141 */
142
143/*
144 * alignment has to be a power of 2 value.
145 */
146static void * __init __alloc_bootmem_core (bootmem_data_t *bdata,
147	unsigned long size, unsigned long align, unsigned long goal)
148{
149	unsigned long i, start = 0;
150	void *ret;
151	unsigned long offset, remaining_size;
152	unsigned long areasize, preferred, incr;
153	unsigned long eidx = bdata->node_low_pfn - (bdata->node_boot_start >>
154							PAGE_SHIFT);
155
156	if (!size) BUG();
157
158	if (align & (align-1))
159		BUG();
160
161	offset = 0;
162	if (align &&
163	    (bdata->node_boot_start & (align - 1UL)) != 0)
164		offset = (align - (bdata->node_boot_start & (align - 1UL)));
165	offset >>= PAGE_SHIFT;
166
167	/*
168	 * We try to allocate bootmem pages above 'goal'
169	 * first, then we try to allocate lower pages.
170	 */
171	if (goal && (goal >= bdata->node_boot_start) &&
172			((goal >> PAGE_SHIFT) < bdata->node_low_pfn)) {
173		preferred = goal - bdata->node_boot_start;
174	} else
175		preferred = 0;
176
177	preferred = ((preferred + align - 1) & ~(align - 1)) >> PAGE_SHIFT;
178	preferred += offset;
179	areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
180	incr = align >> PAGE_SHIFT ? : 1;
181
182restart_scan:
183	for (i = preferred; i < eidx; i += incr) {
184		unsigned long j;
185		if (test_bit(i, bdata->node_bootmem_map))
186			continue;
187		for (j = i + 1; j < i + areasize; ++j) {
188			if (j >= eidx)
189				goto fail_block;
190			if (test_bit (j, bdata->node_bootmem_map))
191				goto fail_block;
192		}
193		start = i;
194		goto found;
195	fail_block:;
196	}
197	if (preferred) {
198		preferred = offset;
199		goto restart_scan;
200	}
201	return NULL;
202found:
203	if (start >= eidx)
204		BUG();
205
206	/*
207	 * Is the next page of the previous allocation-end the start
208	 * of this allocation's buffer? If yes then we can 'merge'
209	 * the previous partial page with this allocation.
210	 */
211	if (align <= PAGE_SIZE
212	    && bdata->last_offset && bdata->last_pos+1 == start) {
213		offset = (bdata->last_offset+align-1) & ~(align-1);
214		if (offset > PAGE_SIZE)
215			BUG();
216		remaining_size = PAGE_SIZE-offset;
217		if (size < remaining_size) {
218			areasize = 0;
219			// last_pos unchanged
220			bdata->last_offset = offset+size;
221			ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
222						bdata->node_boot_start);
223		} else {
224			remaining_size = size - remaining_size;
225			areasize = (remaining_size+PAGE_SIZE-1)/PAGE_SIZE;
226			ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
227						bdata->node_boot_start);
228			bdata->last_pos = start+areasize-1;
229			bdata->last_offset = remaining_size;
230		}
231		bdata->last_offset &= ~PAGE_MASK;
232	} else {
233		bdata->last_pos = start + areasize - 1;
234		bdata->last_offset = size & ~PAGE_MASK;
235		ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
236	}
237	/*
238	 * Reserve the area now:
239	 */
240	for (i = start; i < start+areasize; i++)
241		if (test_and_set_bit(i, bdata->node_bootmem_map))
242			BUG();
243#ifndef CONFIG_HWSIM
244	memset(ret, 0, size);
245#endif
246	return ret;
247}
248
249static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
250{
251	struct page *page = pgdat->node_mem_map;
252	bootmem_data_t *bdata = pgdat->bdata;
253	unsigned long i, count, total = 0;
254	unsigned long idx;
255
256	if (!bdata->node_bootmem_map) BUG();
257
258	count = 0;
259	idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
260	for (i = 0; i < idx; i++, page++) {
261		if (!test_bit(i, bdata->node_bootmem_map)) {
262			count++;
263			ClearPageReserved(page);
264			set_page_count(page, 1);
265			__free_page(page);
266		}
267	}
268	total += count;
269
270	/*
271	 * Now free the allocator bitmap itself, it's not
272	 * needed anymore:
273	 */
274	page = virt_to_page(bdata->node_bootmem_map);
275	count = 0;
276	for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {
277		count++;
278		ClearPageReserved(page);
279		set_page_count(page, 1);
280		__free_page(page);
281	}
282	total += count;
283	bdata->node_bootmem_map = NULL;
284
285	return total;
286}
287
288unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn)
289{
290	return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn));
291}
292
293void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
294{
295	reserve_bootmem_core(pgdat->bdata, physaddr, size);
296}
297
298void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
299{
300	return(free_bootmem_core(pgdat->bdata, physaddr, size));
301}
302
303unsigned long __init free_all_bootmem_node (pg_data_t *pgdat)
304{
305	return(free_all_bootmem_core(pgdat));
306}
307
308unsigned long __init init_bootmem (unsigned long start, unsigned long pages)
309{
310	max_low_pfn = pages;
311	min_low_pfn = start;
312	return(init_bootmem_core(&contig_page_data, start, 0, pages));
313}
314
315void __init reserve_bootmem (unsigned long addr, unsigned long size)
316{
317	reserve_bootmem_core(contig_page_data.bdata, addr, size);
318}
319
320void __init free_bootmem (unsigned long addr, unsigned long size)
321{
322	return(free_bootmem_core(contig_page_data.bdata, addr, size));
323}
324
325unsigned long __init free_all_bootmem (void)
326{
327	return(free_all_bootmem_core(&contig_page_data));
328}
329
330void * __init __alloc_bootmem (unsigned long size, unsigned long align, unsigned long goal)
331{
332	pg_data_t *pgdat;
333	void *ptr;
334
335	for_each_pgdat(pgdat)
336		if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
337						align, goal)))
338			return(ptr);
339
340	/*
341	 * Whoops, we cannot satisfy the allocation request.
342	 */
343	printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
344	panic("Out of memory");
345	return NULL;
346}
347
348void * __init __alloc_bootmem_node (pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal)
349{
350	void *ptr;
351
352	ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal);
353	if (ptr)
354		return (ptr);
355
356	/*
357	 * Whoops, we cannot satisfy the allocation request.
358	 */
359	printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
360	panic("Out of memory");
361	return NULL;
362}
363
364