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