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19#include <linux/mm.h>
20#include <linux/module.h>
21#include <linux/swap.h>
22#include <linux/bio.h>
23#include <linux/pagemap.h>
24#include <linux/mempool.h>
25#include <linux/blkdev.h>
26#include <linux/init.h>
27#include <linux/hash.h>
28#include <linux/highmem.h>
29#include <linux/kgdb.h>
30#include <asm/tlbflush.h>
31
32
33#if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
34DEFINE_PER_CPU(int, __kmap_atomic_idx);
35#endif
36
37
38
39
40
41
42
43
44
45#ifdef CONFIG_HIGHMEM
46
47unsigned long totalhigh_pages __read_mostly;
48EXPORT_SYMBOL(totalhigh_pages);
49
50
51EXPORT_PER_CPU_SYMBOL(__kmap_atomic_idx);
52
53unsigned int nr_free_highpages (void)
54{
55 pg_data_t *pgdat;
56 unsigned int pages = 0;
57
58 for_each_online_pgdat(pgdat) {
59 pages += zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
60 NR_FREE_PAGES);
61 if (zone_movable_is_highmem())
62 pages += zone_page_state(
63 &pgdat->node_zones[ZONE_MOVABLE],
64 NR_FREE_PAGES);
65 }
66
67 return pages;
68}
69
70static int pkmap_count[LAST_PKMAP];
71static unsigned int last_pkmap_nr;
72static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kmap_lock);
73
74pte_t * pkmap_page_table;
75
76static DECLARE_WAIT_QUEUE_HEAD(pkmap_map_wait);
77
78
79
80
81
82
83#ifdef ARCH_NEEDS_KMAP_HIGH_GET
84#define lock_kmap() spin_lock_irq(&kmap_lock)
85#define unlock_kmap() spin_unlock_irq(&kmap_lock)
86#define lock_kmap_any(flags) spin_lock_irqsave(&kmap_lock, flags)
87#define unlock_kmap_any(flags) spin_unlock_irqrestore(&kmap_lock, flags)
88#else
89#define lock_kmap() spin_lock(&kmap_lock)
90#define unlock_kmap() spin_unlock(&kmap_lock)
91#define lock_kmap_any(flags) \
92 do { spin_lock(&kmap_lock); (void)(flags); } while (0)
93#define unlock_kmap_any(flags) \
94 do { spin_unlock(&kmap_lock); (void)(flags); } while (0)
95#endif
96
97static void flush_all_zero_pkmaps(void)
98{
99 int i;
100 int need_flush = 0;
101
102 flush_cache_kmaps();
103
104 for (i = 0; i < LAST_PKMAP; i++) {
105 struct page *page;
106
107
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110
111
112
113 if (pkmap_count[i] != 1)
114 continue;
115 pkmap_count[i] = 0;
116
117
118 BUG_ON(pte_none(pkmap_page_table[i]));
119
120
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123
124
125
126
127 page = pte_page(pkmap_page_table[i]);
128 pte_clear(&init_mm, (unsigned long)page_address(page),
129 &pkmap_page_table[i]);
130
131 set_page_address(page, NULL);
132 need_flush = 1;
133 }
134 if (need_flush)
135 flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP));
136}
137
138
139
140
141void kmap_flush_unused(void)
142{
143 lock_kmap();
144 flush_all_zero_pkmaps();
145 unlock_kmap();
146}
147
148static inline unsigned long map_new_virtual(struct page *page)
149{
150 unsigned long vaddr;
151 int count;
152
153start:
154 count = LAST_PKMAP;
155
156 for (;;) {
157 last_pkmap_nr = (last_pkmap_nr + 1) & LAST_PKMAP_MASK;
158 if (!last_pkmap_nr) {
159 flush_all_zero_pkmaps();
160 count = LAST_PKMAP;
161 }
162 if (!pkmap_count[last_pkmap_nr])
163 break;
164 if (--count)
165 continue;
166
167
168
169
170 {
171 DECLARE_WAITQUEUE(wait, current);
172
173 __set_current_state(TASK_UNINTERRUPTIBLE);
174 add_wait_queue(&pkmap_map_wait, &wait);
175 unlock_kmap();
176 schedule();
177 remove_wait_queue(&pkmap_map_wait, &wait);
178 lock_kmap();
179
180
181 if (page_address(page))
182 return (unsigned long)page_address(page);
183
184
185 goto start;
186 }
187 }
188 vaddr = PKMAP_ADDR(last_pkmap_nr);
189 set_pte_at(&init_mm, vaddr,
190 &(pkmap_page_table[last_pkmap_nr]), mk_pte(page, kmap_prot));
191
192 pkmap_count[last_pkmap_nr] = 1;
193 set_page_address(page, (void *)vaddr);
194
195 return vaddr;
196}
197
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204
205
206void *kmap_high(struct page *page)
207{
208 unsigned long vaddr;
209
210
211
212
213
214 lock_kmap();
215 vaddr = (unsigned long)page_address(page);
216 if (!vaddr)
217 vaddr = map_new_virtual(page);
218 pkmap_count[PKMAP_NR(vaddr)]++;
219 BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 2);
220 unlock_kmap();
221 return (void*) vaddr;
222}
223
224EXPORT_SYMBOL(kmap_high);
225
226#ifdef ARCH_NEEDS_KMAP_HIGH_GET
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235
236
237void *kmap_high_get(struct page *page)
238{
239 unsigned long vaddr, flags;
240
241 lock_kmap_any(flags);
242 vaddr = (unsigned long)page_address(page);
243 if (vaddr) {
244 BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 1);
245 pkmap_count[PKMAP_NR(vaddr)]++;
246 }
247 unlock_kmap_any(flags);
248 return (void*) vaddr;
249}
250#endif
251
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257
258
259void kunmap_high(struct page *page)
260{
261 unsigned long vaddr;
262 unsigned long nr;
263 unsigned long flags;
264 int need_wakeup;
265
266 lock_kmap_any(flags);
267 vaddr = (unsigned long)page_address(page);
268 BUG_ON(!vaddr);
269 nr = PKMAP_NR(vaddr);
270
271
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273
274
275 need_wakeup = 0;
276 switch (--pkmap_count[nr]) {
277 case 0:
278 BUG();
279 case 1:
280
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289
290 need_wakeup = waitqueue_active(&pkmap_map_wait);
291 }
292 unlock_kmap_any(flags);
293
294
295 if (need_wakeup)
296 wake_up(&pkmap_map_wait);
297}
298
299EXPORT_SYMBOL(kunmap_high);
300#endif
301
302#if defined(HASHED_PAGE_VIRTUAL)
303
304#define PA_HASH_ORDER 7
305
306
307
308
309struct page_address_map {
310 struct page *page;
311 void *virtual;
312 struct list_head list;
313};
314
315
316
317
318static struct list_head page_address_pool;
319static spinlock_t pool_lock;
320
321
322
323
324static struct page_address_slot {
325 struct list_head lh;
326 spinlock_t lock;
327} ____cacheline_aligned_in_smp page_address_htable[1<<PA_HASH_ORDER];
328
329static struct page_address_slot *page_slot(struct page *page)
330{
331 return &page_address_htable[hash_ptr(page, PA_HASH_ORDER)];
332}
333
334
335
336
337
338
339
340void *page_address(struct page *page)
341{
342 unsigned long flags;
343 void *ret;
344 struct page_address_slot *pas;
345
346 if (!PageHighMem(page))
347 return lowmem_page_address(page);
348
349 pas = page_slot(page);
350 ret = NULL;
351 spin_lock_irqsave(&pas->lock, flags);
352 if (!list_empty(&pas->lh)) {
353 struct page_address_map *pam;
354
355 list_for_each_entry(pam, &pas->lh, list) {
356 if (pam->page == page) {
357 ret = pam->virtual;
358 goto done;
359 }
360 }
361 }
362done:
363 spin_unlock_irqrestore(&pas->lock, flags);
364 return ret;
365}
366
367EXPORT_SYMBOL(page_address);
368
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371
372
373
374void set_page_address(struct page *page, void *virtual)
375{
376 unsigned long flags;
377 struct page_address_slot *pas;
378 struct page_address_map *pam;
379
380 BUG_ON(!PageHighMem(page));
381
382 pas = page_slot(page);
383 if (virtual) {
384 BUG_ON(list_empty(&page_address_pool));
385
386 spin_lock_irqsave(&pool_lock, flags);
387 pam = list_entry(page_address_pool.next,
388 struct page_address_map, list);
389 list_del(&pam->list);
390 spin_unlock_irqrestore(&pool_lock, flags);
391
392 pam->page = page;
393 pam->virtual = virtual;
394
395 spin_lock_irqsave(&pas->lock, flags);
396 list_add_tail(&pam->list, &pas->lh);
397 spin_unlock_irqrestore(&pas->lock, flags);
398 } else {
399 spin_lock_irqsave(&pas->lock, flags);
400 list_for_each_entry(pam, &pas->lh, list) {
401 if (pam->page == page) {
402 list_del(&pam->list);
403 spin_unlock_irqrestore(&pas->lock, flags);
404 spin_lock_irqsave(&pool_lock, flags);
405 list_add_tail(&pam->list, &page_address_pool);
406 spin_unlock_irqrestore(&pool_lock, flags);
407 goto done;
408 }
409 }
410 spin_unlock_irqrestore(&pas->lock, flags);
411 }
412done:
413 return;
414}
415
416static struct page_address_map page_address_maps[LAST_PKMAP];
417
418void __init page_address_init(void)
419{
420 int i;
421
422 INIT_LIST_HEAD(&page_address_pool);
423 for (i = 0; i < ARRAY_SIZE(page_address_maps); i++)
424 list_add(&page_address_maps[i].list, &page_address_pool);
425 for (i = 0; i < ARRAY_SIZE(page_address_htable); i++) {
426 INIT_LIST_HEAD(&page_address_htable[i].lh);
427 spin_lock_init(&page_address_htable[i].lock);
428 }
429 spin_lock_init(&pool_lock);
430}
431
432#endif
433