This source file includes following definitions.
- oom
- free_one_table
- clear_page_tables
- free_page_tables
- clone_page_tables
- copy_page_tables
- unmap_page_range
- zeromap_page_range
- remap_page_range
- put_page
- put_dirty_page
- __do_wp_page
- do_wp_page
- __verify_write
- verify_area
- get_empty_page
- try_to_share
- share_page
- get_empty_pgtable
- handle_no_page
- do_no_page
- do_page_fault
- __bad_pagetable
- __bad_page
- __zero_page
- show_mem
- paging_init
- mem_init
- si_meminfo
- file_mmap_nopage
- file_mmap_free
- file_mmap_share
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36 #include <asm/system.h>
37 #include <linux/config.h>
38
39 #include <linux/signal.h>
40 #include <linux/sched.h>
41 #include <linux/head.h>
42 #include <linux/kernel.h>
43 #include <linux/errno.h>
44 #include <linux/string.h>
45 #include <linux/types.h>
46 #include <linux/ptrace.h>
47 #include <linux/mman.h>
48 #include <linux/segment.h>
49 #include <asm/segment.h>
50
51
52
53
54
55
56 #undef CONFIG_TEST_VERIFY_AREA
57
58 unsigned long high_memory = 0;
59
60 extern unsigned long pg0[1024];
61
62 extern void sound_mem_init(void);
63 extern void die_if_kernel(char *,struct pt_regs *,long);
64 extern void show_net_buffers(void);
65
66
67
68
69
70 int nr_swap_pages = 0;
71 int nr_free_pages = 0;
72 struct mem_list free_area_list[NR_MEM_LISTS];
73 unsigned char * free_area_map[NR_MEM_LISTS];
74
75 #define copy_page(from,to) \
76 __asm__("cld ; rep ; movsl": :"S" (from),"D" (to),"c" (1024):"cx","di","si")
77
78 unsigned short * mem_map = NULL;
79
80 #define CODE_SPACE(addr,p) ((addr) < (p)->end_code)
81
82
83
84
85
86 void oom(struct task_struct * task)
87 {
88 printk("\nOut of memory.\n");
89 task->sigaction[SIGKILL-1].sa_handler = NULL;
90 task->blocked &= ~(1<<(SIGKILL-1));
91 send_sig(SIGKILL,task,1);
92 }
93
94 static void free_one_table(unsigned long * page_dir)
95 {
96 int j;
97 unsigned long pg_table = *page_dir;
98 unsigned long * page_table;
99
100 if (!pg_table)
101 return;
102 *page_dir = 0;
103 if (pg_table >= high_memory || !(pg_table & PAGE_PRESENT)) {
104 printk("Bad page table: [%p]=%08lx\n",page_dir,pg_table);
105 return;
106 }
107 if (mem_map[MAP_NR(pg_table)] & MAP_PAGE_RESERVED)
108 return;
109 page_table = (unsigned long *) (pg_table & PAGE_MASK);
110 for (j = 0 ; j < PTRS_PER_PAGE ; j++,page_table++) {
111 unsigned long pg = *page_table;
112
113 if (!pg)
114 continue;
115 *page_table = 0;
116 if (pg & PAGE_PRESENT)
117 free_page(PAGE_MASK & pg);
118 else
119 swap_free(pg);
120 }
121 free_page(PAGE_MASK & pg_table);
122 }
123
124
125
126
127
128
129
130
131 void clear_page_tables(struct task_struct * tsk)
132 {
133 int i;
134 unsigned long pg_dir;
135 unsigned long * page_dir;
136
137 if (!tsk)
138 return;
139 if (tsk == task[0])
140 panic("task[0] (swapper) doesn't support exec()\n");
141 pg_dir = tsk->tss.cr3;
142 page_dir = (unsigned long *) pg_dir;
143 if (!page_dir || page_dir == swapper_pg_dir) {
144 printk("Trying to clear kernel page-directory: not good\n");
145 return;
146 }
147 if (mem_map[MAP_NR(pg_dir)] > 1) {
148 unsigned long * new_pg;
149
150 if (!(new_pg = (unsigned long*) get_free_page(GFP_KERNEL))) {
151 oom(tsk);
152 return;
153 }
154 for (i = 768 ; i < 1024 ; i++)
155 new_pg[i] = page_dir[i];
156 free_page(pg_dir);
157 tsk->tss.cr3 = (unsigned long) new_pg;
158 return;
159 }
160 for (i = 0 ; i < 768 ; i++,page_dir++)
161 free_one_table(page_dir);
162 invalidate();
163 return;
164 }
165
166
167
168
169 void free_page_tables(struct task_struct * tsk)
170 {
171 int i;
172 unsigned long pg_dir;
173 unsigned long * page_dir;
174
175 if (!tsk)
176 return;
177 if (tsk == task[0]) {
178 printk("task[0] (swapper) killed: unable to recover\n");
179 panic("Trying to free up swapper memory space");
180 }
181 pg_dir = tsk->tss.cr3;
182 if (!pg_dir || pg_dir == (unsigned long) swapper_pg_dir) {
183 printk("Trying to free kernel page-directory: not good\n");
184 return;
185 }
186 tsk->tss.cr3 = (unsigned long) swapper_pg_dir;
187 if (tsk == current)
188 __asm__ __volatile__("movl %0,%%cr3": :"a" (tsk->tss.cr3));
189 if (mem_map[MAP_NR(pg_dir)] > 1) {
190 free_page(pg_dir);
191 return;
192 }
193 page_dir = (unsigned long *) pg_dir;
194 for (i = 0 ; i < PTRS_PER_PAGE ; i++,page_dir++)
195 free_one_table(page_dir);
196 free_page(pg_dir);
197 invalidate();
198 }
199
200
201
202
203
204
205
206 int clone_page_tables(struct task_struct * tsk)
207 {
208 unsigned long pg_dir;
209
210 pg_dir = current->tss.cr3;
211 mem_map[MAP_NR(pg_dir)]++;
212 tsk->tss.cr3 = pg_dir;
213 return 0;
214 }
215
216
217
218
219
220
221 int copy_page_tables(struct task_struct * tsk)
222 {
223 int i;
224 unsigned long old_pg_dir, *old_page_dir;
225 unsigned long new_pg_dir, *new_page_dir;
226
227 if (!(new_pg_dir = get_free_page(GFP_KERNEL)))
228 return -ENOMEM;
229 old_pg_dir = current->tss.cr3;
230 tsk->tss.cr3 = new_pg_dir;
231 old_page_dir = (unsigned long *) old_pg_dir;
232 new_page_dir = (unsigned long *) new_pg_dir;
233 for (i = 0 ; i < PTRS_PER_PAGE ; i++,old_page_dir++,new_page_dir++) {
234 int j;
235 unsigned long old_pg_table, *old_page_table;
236 unsigned long new_pg_table, *new_page_table;
237
238 old_pg_table = *old_page_dir;
239 if (!old_pg_table)
240 continue;
241 if (old_pg_table >= high_memory || !(old_pg_table & PAGE_PRESENT)) {
242 printk("copy_page_tables: bad page table: "
243 "probable memory corruption");
244 *old_page_dir = 0;
245 continue;
246 }
247 if (mem_map[MAP_NR(old_pg_table)] & MAP_PAGE_RESERVED) {
248 *new_page_dir = old_pg_table;
249 continue;
250 }
251 if (!(new_pg_table = get_free_page(GFP_KERNEL))) {
252 free_page_tables(tsk);
253 return -ENOMEM;
254 }
255 old_page_table = (unsigned long *) (PAGE_MASK & old_pg_table);
256 new_page_table = (unsigned long *) (PAGE_MASK & new_pg_table);
257 for (j = 0 ; j < PTRS_PER_PAGE ; j++,old_page_table++,new_page_table++) {
258 unsigned long pg;
259 pg = *old_page_table;
260 if (!pg)
261 continue;
262 if (!(pg & PAGE_PRESENT)) {
263 *new_page_table = swap_duplicate(pg);
264 continue;
265 }
266 if ((pg & (PAGE_RW | PAGE_COW)) == (PAGE_RW | PAGE_COW))
267 pg &= ~PAGE_RW;
268 *new_page_table = pg;
269 if (mem_map[MAP_NR(pg)] & MAP_PAGE_RESERVED)
270 continue;
271 *old_page_table = pg;
272 mem_map[MAP_NR(pg)]++;
273 }
274 *new_page_dir = new_pg_table | PAGE_TABLE;
275 }
276 invalidate();
277 return 0;
278 }
279
280
281
282
283
284 int unmap_page_range(unsigned long from, unsigned long size)
285 {
286 unsigned long page, page_dir;
287 unsigned long *page_table, *dir;
288 unsigned long poff, pcnt, pc;
289
290 if (from & ~PAGE_MASK) {
291 printk("unmap_page_range called with wrong alignment\n");
292 return -EINVAL;
293 }
294 size = (size + ~PAGE_MASK) >> PAGE_SHIFT;
295 dir = PAGE_DIR_OFFSET(current->tss.cr3,from);
296 poff = (from >> PAGE_SHIFT) & (PTRS_PER_PAGE-1);
297 if ((pcnt = PTRS_PER_PAGE - poff) > size)
298 pcnt = size;
299
300 for ( ; size > 0; ++dir, size -= pcnt,
301 pcnt = (size > PTRS_PER_PAGE ? PTRS_PER_PAGE : size)) {
302 if (!(page_dir = *dir)) {
303 poff = 0;
304 continue;
305 }
306 if (!(page_dir & PAGE_PRESENT)) {
307 printk("unmap_page_range: bad page directory.");
308 continue;
309 }
310 page_table = (unsigned long *)(PAGE_MASK & page_dir);
311 if (poff) {
312 page_table += poff;
313 poff = 0;
314 }
315 for (pc = pcnt; pc--; page_table++) {
316 if ((page = *page_table) != 0) {
317 *page_table = 0;
318 if (1 & page) {
319 if (!(mem_map[MAP_NR(page)] & MAP_PAGE_RESERVED))
320 if (current->mm->rss > 0)
321 --current->mm->rss;
322 free_page(PAGE_MASK & page);
323 } else
324 swap_free(page);
325 }
326 }
327 if (pcnt == PTRS_PER_PAGE) {
328 *dir = 0;
329 free_page(PAGE_MASK & page_dir);
330 }
331 }
332 invalidate();
333 return 0;
334 }
335
336 int zeromap_page_range(unsigned long from, unsigned long size, int mask)
337 {
338 unsigned long *page_table, *dir;
339 unsigned long poff, pcnt;
340 unsigned long page;
341
342 if (mask) {
343 if ((mask & (PAGE_MASK|PAGE_PRESENT)) != PAGE_PRESENT) {
344 printk("zeromap_page_range: mask = %08x\n",mask);
345 return -EINVAL;
346 }
347 mask |= ZERO_PAGE;
348 }
349 if (from & ~PAGE_MASK) {
350 printk("zeromap_page_range: from = %08lx\n",from);
351 return -EINVAL;
352 }
353 dir = PAGE_DIR_OFFSET(current->tss.cr3,from);
354 size = (size + ~PAGE_MASK) >> PAGE_SHIFT;
355 poff = (from >> PAGE_SHIFT) & (PTRS_PER_PAGE-1);
356 if ((pcnt = PTRS_PER_PAGE - poff) > size)
357 pcnt = size;
358
359 while (size > 0) {
360 if (!(PAGE_PRESENT & *dir)) {
361
362 if (!(page_table = (unsigned long*) get_free_page(GFP_KERNEL))) {
363 invalidate();
364 return -ENOMEM;
365 }
366 if (PAGE_PRESENT & *dir) {
367 free_page((unsigned long) page_table);
368 page_table = (unsigned long *)(PAGE_MASK & *dir++);
369 } else
370 *dir++ = ((unsigned long) page_table) | PAGE_TABLE;
371 } else
372 page_table = (unsigned long *)(PAGE_MASK & *dir++);
373 page_table += poff;
374 poff = 0;
375 for (size -= pcnt; pcnt-- ;) {
376 if ((page = *page_table) != 0) {
377 *page_table = 0;
378 if (page & PAGE_PRESENT) {
379 if (!(mem_map[MAP_NR(page)] & MAP_PAGE_RESERVED))
380 if (current->mm->rss > 0)
381 --current->mm->rss;
382 free_page(PAGE_MASK & page);
383 } else
384 swap_free(page);
385 }
386 *page_table++ = mask;
387 }
388 pcnt = (size > PTRS_PER_PAGE ? PTRS_PER_PAGE : size);
389 }
390 invalidate();
391 return 0;
392 }
393
394
395
396
397
398
399 int remap_page_range(unsigned long from, unsigned long to, unsigned long size, int mask)
400 {
401 unsigned long *page_table, *dir;
402 unsigned long poff, pcnt;
403 unsigned long page;
404
405 if (mask) {
406 if ((mask & (PAGE_MASK|PAGE_PRESENT)) != PAGE_PRESENT) {
407 printk("remap_page_range: mask = %08x\n",mask);
408 return -EINVAL;
409 }
410 }
411 if ((from & ~PAGE_MASK) || (to & ~PAGE_MASK)) {
412 printk("remap_page_range: from = %08lx, to=%08lx\n",from,to);
413 return -EINVAL;
414 }
415 dir = PAGE_DIR_OFFSET(current->tss.cr3,from);
416 size = (size + ~PAGE_MASK) >> PAGE_SHIFT;
417 poff = (from >> PAGE_SHIFT) & (PTRS_PER_PAGE-1);
418 if ((pcnt = PTRS_PER_PAGE - poff) > size)
419 pcnt = size;
420
421 while (size > 0) {
422 if (!(PAGE_PRESENT & *dir)) {
423
424 if (!(page_table = (unsigned long*) get_free_page(GFP_KERNEL))) {
425 invalidate();
426 return -1;
427 }
428 *dir++ = ((unsigned long) page_table) | PAGE_TABLE;
429 }
430 else
431 page_table = (unsigned long *)(PAGE_MASK & *dir++);
432 if (poff) {
433 page_table += poff;
434 poff = 0;
435 }
436
437 for (size -= pcnt; pcnt-- ;) {
438 if ((page = *page_table) != 0) {
439 *page_table = 0;
440 if (PAGE_PRESENT & page) {
441 if (!(mem_map[MAP_NR(page)] & MAP_PAGE_RESERVED))
442 if (current->mm->rss > 0)
443 --current->mm->rss;
444 free_page(PAGE_MASK & page);
445 } else
446 swap_free(page);
447 }
448
449
450
451
452
453
454
455 if (!mask)
456 *page_table++ = 0;
457 else if (to >= high_memory)
458 *page_table++ = (to | mask);
459 else if (!mem_map[MAP_NR(to)])
460 *page_table++ = 0;
461 else {
462 *page_table++ = (to | mask);
463 if (!(mem_map[MAP_NR(to)] & MAP_PAGE_RESERVED)) {
464 ++current->mm->rss;
465 mem_map[MAP_NR(to)]++;
466 }
467 }
468 to += PAGE_SIZE;
469 }
470 pcnt = (size > PTRS_PER_PAGE ? PTRS_PER_PAGE : size);
471 }
472 invalidate();
473 return 0;
474 }
475
476
477
478
479
480
481
482 unsigned long put_page(struct task_struct * tsk,unsigned long page,
483 unsigned long address,int prot)
484 {
485 unsigned long *page_table;
486
487 if ((prot & (PAGE_MASK|PAGE_PRESENT)) != PAGE_PRESENT)
488 printk("put_page: prot = %08x\n",prot);
489 if (page >= high_memory) {
490 printk("put_page: trying to put page %08lx at %08lx\n",page,address);
491 return 0;
492 }
493 page_table = PAGE_DIR_OFFSET(tsk->tss.cr3,address);
494 if ((*page_table) & PAGE_PRESENT)
495 page_table = (unsigned long *) (PAGE_MASK & *page_table);
496 else {
497 printk("put_page: bad page directory entry\n");
498 oom(tsk);
499 *page_table = BAD_PAGETABLE | PAGE_TABLE;
500 return 0;
501 }
502 page_table += (address >> PAGE_SHIFT) & (PTRS_PER_PAGE-1);
503 if (*page_table) {
504 printk("put_page: page already exists\n");
505 *page_table = 0;
506 invalidate();
507 }
508 *page_table = page | prot;
509
510 return page;
511 }
512
513
514
515
516
517
518
519 unsigned long put_dirty_page(struct task_struct * tsk, unsigned long page, unsigned long address)
520 {
521 unsigned long tmp, *page_table;
522
523 if (page >= high_memory)
524 printk("put_dirty_page: trying to put page %08lx at %08lx\n",page,address);
525 if (mem_map[MAP_NR(page)] != 1)
526 printk("mem_map disagrees with %08lx at %08lx\n",page,address);
527 page_table = PAGE_DIR_OFFSET(tsk->tss.cr3,address);
528 if (PAGE_PRESENT & *page_table)
529 page_table = (unsigned long *) (PAGE_MASK & *page_table);
530 else {
531 if (!(tmp = get_free_page(GFP_KERNEL)))
532 return 0;
533 if (PAGE_PRESENT & *page_table) {
534 free_page(tmp);
535 page_table = (unsigned long *) (PAGE_MASK & *page_table);
536 } else {
537 *page_table = tmp | PAGE_TABLE;
538 page_table = (unsigned long *) tmp;
539 }
540 }
541 page_table += (address >> PAGE_SHIFT) & (PTRS_PER_PAGE-1);
542 if (*page_table) {
543 printk("put_dirty_page: page already exists\n");
544 *page_table = 0;
545 invalidate();
546 }
547 *page_table = page | (PAGE_DIRTY | PAGE_PRIVATE);
548
549 return page;
550 }
551
552
553
554
555
556
557
558
559
560
561
562
563 static void __do_wp_page(unsigned long error_code, unsigned long address,
564 struct task_struct * tsk)
565 {
566 unsigned long *pde, pte, old_page, prot;
567 unsigned long new_page;
568
569 new_page = __get_free_page(GFP_KERNEL);
570 pde = PAGE_DIR_OFFSET(tsk->tss.cr3,address);
571 pte = *pde;
572 if (!(pte & PAGE_PRESENT))
573 goto end_wp_page;
574 if ((pte & PAGE_TABLE) != PAGE_TABLE || pte >= high_memory)
575 goto bad_wp_pagetable;
576 pte &= PAGE_MASK;
577 pte += PAGE_PTR(address);
578 old_page = *(unsigned long *) pte;
579 if (!(old_page & PAGE_PRESENT))
580 goto end_wp_page;
581 if (old_page >= high_memory)
582 goto bad_wp_page;
583 if (old_page & PAGE_RW)
584 goto end_wp_page;
585 tsk->mm->min_flt++;
586 prot = (old_page & ~PAGE_MASK) | PAGE_RW;
587 old_page &= PAGE_MASK;
588 if (mem_map[MAP_NR(old_page)] != 1) {
589 if (new_page) {
590 if (mem_map[MAP_NR(old_page)] & MAP_PAGE_RESERVED)
591 ++tsk->mm->rss;
592 copy_page(old_page,new_page);
593 *(unsigned long *) pte = new_page | prot;
594 free_page(old_page);
595 invalidate();
596 return;
597 }
598 free_page(old_page);
599 oom(tsk);
600 *(unsigned long *) pte = BAD_PAGE | prot;
601 invalidate();
602 return;
603 }
604 *(unsigned long *) pte |= PAGE_RW;
605 invalidate();
606 if (new_page)
607 free_page(new_page);
608 return;
609 bad_wp_page:
610 printk("do_wp_page: bogus page at address %08lx (%08lx)\n",address,old_page);
611 *(unsigned long *) pte = BAD_PAGE | PAGE_SHARED;
612 send_sig(SIGKILL, tsk, 1);
613 goto end_wp_page;
614 bad_wp_pagetable:
615 printk("do_wp_page: bogus page-table at address %08lx (%08lx)\n",address,pte);
616 *pde = BAD_PAGETABLE | PAGE_TABLE;
617 send_sig(SIGKILL, tsk, 1);
618 end_wp_page:
619 if (new_page)
620 free_page(new_page);
621 return;
622 }
623
624
625
626
627
628 void do_wp_page(unsigned long error_code, unsigned long address,
629 struct task_struct * tsk)
630 {
631 unsigned long page;
632 unsigned long * pg_table;
633
634 pg_table = PAGE_DIR_OFFSET(tsk->tss.cr3,address);
635 page = *pg_table;
636 if (!page)
637 return;
638 if ((page & PAGE_PRESENT) && page < high_memory) {
639 pg_table = (unsigned long *) ((page & PAGE_MASK) + PAGE_PTR(address));
640 page = *pg_table;
641 if (!(page & PAGE_PRESENT))
642 return;
643 if (page & PAGE_RW)
644 return;
645 if (!(page & PAGE_COW)) {
646 if ((error_code & PAGE_USER) && tsk == current) {
647 current->tss.cr2 = address;
648 current->tss.error_code = error_code;
649 current->tss.trap_no = 14;
650 send_sig(SIGSEGV, tsk, 1);
651 return;
652 }
653 }
654 if (mem_map[MAP_NR(page)] == 1) {
655 *pg_table |= PAGE_RW | PAGE_DIRTY;
656 invalidate();
657 return;
658 }
659 __do_wp_page(error_code, address, tsk);
660 return;
661 }
662 printk("bad page directory entry %08lx\n",page);
663 *pg_table = 0;
664 }
665
666 static int __verify_write(unsigned long start, unsigned long size)
667 {
668 size--;
669 size += start & ~PAGE_MASK;
670 size >>= PAGE_SHIFT;
671 start &= PAGE_MASK;
672 do {
673 do_wp_page(1,start,current);
674 start += PAGE_SIZE;
675 } while (size--);
676 return 0;
677 }
678
679 int verify_area(int type, const void * addr, unsigned long size)
680 {
681 struct vm_area_struct * vma;
682
683
684
685
686
687 if (get_fs() == get_ds())
688 return 0;
689
690 for (vma = current->mm->mmap ; ; vma = vma->vm_next) {
691 if (!vma)
692 goto bad_area;
693 if (vma->vm_end > (unsigned long) addr)
694 break;
695 }
696 if (vma->vm_start <= (unsigned long) addr)
697 goto good_area;
698 if (!(vma->vm_flags & VM_GROWSDOWN))
699 goto bad_area;
700 if (vma->vm_end - (unsigned long) addr > current->rlim[RLIMIT_STACK].rlim_cur)
701 goto bad_area;
702 good_area:
703 while (vma->vm_end - (unsigned long) addr < size) {
704 struct vm_area_struct * next = vma->vm_next;
705 if (!next)
706 goto bad_area;
707 if (vma->vm_end != next->vm_start)
708 goto bad_area;
709 vma = next;
710 }
711 if (wp_works_ok || type == VERIFY_READ || !size)
712 return 0;
713 return __verify_write((unsigned long) addr,size);
714 bad_area:
715 return -EFAULT;
716 }
717
718 static inline void get_empty_page(struct task_struct * tsk, unsigned long address)
719 {
720 unsigned long tmp;
721
722 if (!(tmp = get_free_page(GFP_KERNEL))) {
723 oom(tsk);
724 tmp = BAD_PAGE;
725 }
726 if (!put_page(tsk,tmp,address,PAGE_PRIVATE))
727 free_page(tmp);
728 }
729
730
731
732
733
734
735
736
737
738 static int try_to_share(unsigned long to_address, struct vm_area_struct * to_area,
739 unsigned long from_address, struct vm_area_struct * from_area,
740 unsigned long newpage)
741 {
742 unsigned long from;
743 unsigned long to;
744 unsigned long from_page;
745 unsigned long to_page;
746
747 from_page = (unsigned long)PAGE_DIR_OFFSET(from_area->vm_task->tss.cr3,from_address);
748 to_page = (unsigned long)PAGE_DIR_OFFSET(to_area->vm_task->tss.cr3,to_address);
749
750 from = *(unsigned long *) from_page;
751 if (!(from & PAGE_PRESENT))
752 return 0;
753 from &= PAGE_MASK;
754 from_page = from + PAGE_PTR(from_address);
755 from = *(unsigned long *) from_page;
756
757 if ((from & (PAGE_PRESENT | PAGE_DIRTY)) != PAGE_PRESENT)
758 return 0;
759 if (from >= high_memory)
760 return 0;
761 if (mem_map[MAP_NR(from)] & MAP_PAGE_RESERVED)
762 return 0;
763
764 to = *(unsigned long *) to_page;
765 if (!(to & PAGE_PRESENT))
766 return 0;
767 to &= PAGE_MASK;
768 to_page = to + PAGE_PTR(to_address);
769 if (*(unsigned long *) to_page)
770 return 0;
771
772 if (newpage) {
773 copy_page((from & PAGE_MASK), newpage);
774 *(unsigned long *) to_page = newpage | to_area->vm_page_prot;
775 return 1;
776 }
777
778 mem_map[MAP_NR(from)]++;
779
780 to = (from & PAGE_MASK) | to_area->vm_page_prot;
781 if (to & PAGE_COW)
782 to &= ~PAGE_RW;
783 *(unsigned long *) to_page = to;
784
785 if (!(from & PAGE_RW))
786 return 1;
787 if (!(from_area->vm_page_prot & PAGE_COW))
788 return 1;
789
790 from &= ~PAGE_RW;
791 *(unsigned long *) from_page = from;
792 invalidate();
793 return 1;
794 }
795
796
797
798
799
800
801
802
803 static int share_page(struct vm_area_struct * area, unsigned long address,
804 unsigned long error_code, unsigned long newpage)
805 {
806 struct inode * inode;
807 struct task_struct ** p;
808 unsigned long offset;
809 unsigned long from_address;
810 unsigned long give_page;
811
812 if (!area || !(inode = area->vm_inode) || inode->i_count < 2)
813 return 0;
814
815 give_page = 0;
816 if ((area->vm_page_prot & PAGE_COW) && (error_code & PAGE_RW)) {
817 if (!newpage)
818 return 0;
819 give_page = newpage;
820 }
821 offset = address - area->vm_start + area->vm_offset;
822 for (p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
823 struct vm_area_struct * mpnt;
824 if (!*p)
825 continue;
826 if (area->vm_task == *p)
827 continue;
828
829
830 for (mpnt = (*p)->mm->mmap; mpnt; mpnt = mpnt->vm_next) {
831
832 if (mpnt->vm_inode != inode)
833 continue;
834
835 if ((mpnt->vm_offset ^ area->vm_offset) & ~PAGE_MASK)
836 continue;
837
838 from_address = offset + mpnt->vm_start - mpnt->vm_offset;
839 if (from_address < mpnt->vm_start || from_address >= mpnt->vm_end)
840 continue;
841
842 if (!try_to_share(address, area, from_address, mpnt, give_page))
843 continue;
844
845 if (give_page || !newpage)
846 return 1;
847 free_page(newpage);
848 return 1;
849 }
850 }
851 return 0;
852 }
853
854
855
856
857 static inline unsigned long get_empty_pgtable(struct task_struct * tsk,unsigned long address)
858 {
859 unsigned long page;
860 unsigned long *p;
861
862 p = PAGE_DIR_OFFSET(tsk->tss.cr3,address);
863 if (PAGE_PRESENT & *p)
864 return *p;
865 if (*p) {
866 printk("get_empty_pgtable: bad page-directory entry \n");
867 *p = 0;
868 }
869 page = get_free_page(GFP_KERNEL);
870 p = PAGE_DIR_OFFSET(tsk->tss.cr3,address);
871 if (PAGE_PRESENT & *p) {
872 free_page(page);
873 return *p;
874 }
875 if (*p) {
876 printk("get_empty_pgtable: bad page-directory entry \n");
877 *p = 0;
878 }
879 if (page) {
880 *p = page | PAGE_TABLE;
881 return *p;
882 }
883 oom(current);
884 *p = BAD_PAGETABLE | PAGE_TABLE;
885 return 0;
886 }
887
888 static void handle_no_page(struct vm_area_struct * vma,
889 unsigned long address, unsigned long error_code)
890 {
891 unsigned long page;
892 int prot;
893
894 page = get_free_page(GFP_KERNEL);
895 if (share_page(vma, address, error_code, page)) {
896 ++vma->vm_task->mm->min_flt;
897 return;
898 }
899 if (!page) {
900 oom(current);
901 put_page(vma->vm_task, BAD_PAGE, address, PAGE_PRIVATE);
902 return;
903 }
904 ++vma->vm_task->mm->maj_flt;
905 ++vma->vm_task->mm->rss;
906 page = vma->vm_ops->nopage(vma, address, page, error_code);
907 if (share_page(vma, address, error_code, 0))
908 return;
909 prot = vma->vm_page_prot;
910 if ((prot & PAGE_COW) && mem_map[MAP_NR(page)] > 1)
911 prot &= ~PAGE_RW;
912 if (put_page(vma->vm_task, page, address, prot))
913 return;
914 free_page(page);
915 oom(current);
916 }
917
918 void do_no_page(unsigned long error_code, unsigned long address,
919 struct task_struct *tsk)
920 {
921 unsigned long page, tmp;
922 struct vm_area_struct * vma;
923
924 page = get_empty_pgtable(tsk,address);
925 if (!page)
926 return;
927 page &= PAGE_MASK;
928 page += PAGE_PTR(address);
929 tmp = *(unsigned long *) page;
930 if (tmp & PAGE_PRESENT)
931 return;
932 if (tmp) {
933 ++tsk->mm->rss;
934 ++tsk->mm->maj_flt;
935 swap_in((unsigned long *) page);
936 return;
937 }
938 address &= PAGE_MASK;
939 for (vma = tsk->mm->mmap ; ; vma = vma->vm_next) {
940 if (!vma)
941 goto bad_area;
942 if (vma->vm_end > address)
943 break;
944 }
945 if (vma->vm_start <= address)
946 goto good_area;
947 if (!(vma->vm_flags & VM_GROWSDOWN))
948 goto bad_area;
949 if (vma->vm_end - address > tsk->rlim[RLIMIT_STACK].rlim_cur)
950 goto bad_area;
951 vma->vm_offset -= vma->vm_start - address;
952 vma->vm_start = address;
953
954 good_area:
955 if (!vma->vm_ops || !vma->vm_ops->nopage) {
956 ++tsk->mm->rss;
957 ++tsk->mm->min_flt;
958 get_empty_page(tsk,address);
959 return;
960 }
961 handle_no_page(vma, address, error_code);
962 return;
963
964 bad_area:
965 if (tsk != current)
966 goto kernel_needs_bad_page;
967 tsk->tss.cr2 = address;
968 tsk->tss.error_code = error_code;
969 tsk->tss.trap_no = 14;
970 send_sig(SIGSEGV,tsk,1);
971 if (error_code & 4)
972 return;
973
974 kernel_needs_bad_page:
975 ++tsk->mm->rss;
976 ++tsk->mm->min_flt;
977 get_empty_page(tsk,address);
978 }
979
980
981
982
983
984
985 asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code)
986 {
987 unsigned long address;
988 unsigned long page;
989 unsigned int bit;
990
991
992 __asm__("movl %%cr2,%0":"=r" (address));
993 if (address < TASK_SIZE) {
994 if (regs->eflags & VM_MASK) {
995 bit = (address - 0xA0000) >> PAGE_SHIFT;
996 if (bit < 32)
997 current->screen_bitmap |= 1 << bit;
998 }
999 if (error_code & PAGE_PRESENT) {
1000 #ifdef CONFIG_TEST_VERIFY_AREA
1001 if (regs->cs == KERNEL_CS)
1002 printk("WP fault at %08x\n", regs->eip);
1003 #endif
1004 do_wp_page(error_code, address, current);
1005 } else {
1006 do_no_page(error_code, address, current);
1007 }
1008 return;
1009 }
1010 address -= TASK_SIZE;
1011 if (wp_works_ok < 0 && address == 0 && (error_code & PAGE_PRESENT)) {
1012 wp_works_ok = 1;
1013 pg0[0] = PAGE_SHARED;
1014 printk("This processor honours the WP bit even when in supervisor mode. Good.\n");
1015 return;
1016 }
1017 if (address < PAGE_SIZE) {
1018 printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
1019 pg0[0] = PAGE_SHARED;
1020 } else
1021 printk(KERN_ALERT "Unable to handle kernel paging request");
1022 printk(" at kernel address %08lx\n",address);
1023 address += TASK_SIZE;
1024 __asm__("movl %%cr3,%0" : "=r" (page));
1025 printk(KERN_ALERT "current->tss.cr3 = %08lx, %%cr3 = %08lx\n",
1026 current->tss.cr3, page);
1027 page = ((unsigned long *) page)[address >> 22];
1028 printk(KERN_ALERT "*pde = %08lx\n", page);
1029 if (page & PAGE_PRESENT) {
1030 page &= PAGE_MASK;
1031 address &= 0x003ff000;
1032 page = ((unsigned long *) page)[address >> PAGE_SHIFT];
1033 printk(KERN_ALERT "*pte = %08lx\n", page);
1034 }
1035 die_if_kernel("Oops", regs, error_code);
1036 do_exit(SIGKILL);
1037 }
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052 unsigned long __bad_pagetable(void)
1053 {
1054 extern char empty_bad_page_table[PAGE_SIZE];
1055
1056 __asm__ __volatile__("cld ; rep ; stosl":
1057 :"a" (BAD_PAGE + PAGE_TABLE),
1058 "D" ((long) empty_bad_page_table),
1059 "c" (PTRS_PER_PAGE)
1060 :"di","cx");
1061 return (unsigned long) empty_bad_page_table;
1062 }
1063
1064 unsigned long __bad_page(void)
1065 {
1066 extern char empty_bad_page[PAGE_SIZE];
1067
1068 __asm__ __volatile__("cld ; rep ; stosl":
1069 :"a" (0),
1070 "D" ((long) empty_bad_page),
1071 "c" (PTRS_PER_PAGE)
1072 :"di","cx");
1073 return (unsigned long) empty_bad_page;
1074 }
1075
1076 unsigned long __zero_page(void)
1077 {
1078 extern char empty_zero_page[PAGE_SIZE];
1079
1080 __asm__ __volatile__("cld ; rep ; stosl":
1081 :"a" (0),
1082 "D" ((long) empty_zero_page),
1083 "c" (PTRS_PER_PAGE)
1084 :"di","cx");
1085 return (unsigned long) empty_zero_page;
1086 }
1087
1088 void show_mem(void)
1089 {
1090 int i,free = 0,total = 0,reserved = 0;
1091 int shared = 0;
1092
1093 printk("Mem-info:\n");
1094 show_free_areas();
1095 printk("Free swap: %6dkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
1096 i = high_memory >> PAGE_SHIFT;
1097 while (i-- > 0) {
1098 total++;
1099 if (mem_map[i] & MAP_PAGE_RESERVED)
1100 reserved++;
1101 else if (!mem_map[i])
1102 free++;
1103 else
1104 shared += mem_map[i]-1;
1105 }
1106 printk("%d pages of RAM\n",total);
1107 printk("%d free pages\n",free);
1108 printk("%d reserved pages\n",reserved);
1109 printk("%d pages shared\n",shared);
1110 show_buffers();
1111 #ifdef CONFIG_NET
1112 show_net_buffers();
1113 #endif
1114 }
1115
1116 extern unsigned long free_area_init(unsigned long, unsigned long);
1117
1118
1119
1120
1121
1122
1123
1124
1125 unsigned long paging_init(unsigned long start_mem, unsigned long end_mem)
1126 {
1127 unsigned long * pg_dir;
1128 unsigned long * pg_table;
1129 unsigned long tmp;
1130 unsigned long address;
1131
1132
1133
1134
1135
1136
1137
1138 #if 0
1139 memset((void *) 0, 0, PAGE_SIZE);
1140 #endif
1141 start_mem = PAGE_ALIGN(start_mem);
1142 address = 0;
1143 pg_dir = swapper_pg_dir;
1144 while (address < end_mem) {
1145 tmp = *(pg_dir + 768);
1146 if (!tmp) {
1147 tmp = start_mem | PAGE_TABLE;
1148 *(pg_dir + 768) = tmp;
1149 start_mem += PAGE_SIZE;
1150 }
1151 *pg_dir = tmp;
1152 pg_dir++;
1153 pg_table = (unsigned long *) (tmp & PAGE_MASK);
1154 for (tmp = 0 ; tmp < PTRS_PER_PAGE ; tmp++,pg_table++) {
1155 if (address < end_mem)
1156 *pg_table = address | PAGE_SHARED;
1157 else
1158 *pg_table = 0;
1159 address += PAGE_SIZE;
1160 }
1161 }
1162 invalidate();
1163 return free_area_init(start_mem, end_mem);
1164 }
1165
1166 void mem_init(unsigned long start_low_mem,
1167 unsigned long start_mem, unsigned long end_mem)
1168 {
1169 int codepages = 0;
1170 int reservedpages = 0;
1171 int datapages = 0;
1172 unsigned long tmp;
1173 extern int etext;
1174
1175 cli();
1176 end_mem &= PAGE_MASK;
1177 high_memory = end_mem;
1178
1179
1180 start_low_mem = PAGE_ALIGN(start_low_mem);
1181 start_mem = PAGE_ALIGN(start_mem);
1182
1183
1184
1185
1186
1187
1188 while (start_low_mem < 0x9f000) {
1189 mem_map[MAP_NR(start_low_mem)] = 0;
1190 start_low_mem += PAGE_SIZE;
1191 }
1192
1193 while (start_mem < high_memory) {
1194 mem_map[MAP_NR(start_mem)] = 0;
1195 start_mem += PAGE_SIZE;
1196 }
1197 #ifdef CONFIG_SOUND
1198 sound_mem_init();
1199 #endif
1200 for (tmp = 0 ; tmp < high_memory ; tmp += PAGE_SIZE) {
1201 if (mem_map[MAP_NR(tmp)]) {
1202 if (tmp >= 0xA0000 && tmp < 0x100000)
1203 reservedpages++;
1204 else if (tmp < (unsigned long) &etext)
1205 codepages++;
1206 else
1207 datapages++;
1208 continue;
1209 }
1210 mem_map[MAP_NR(tmp)] = 1;
1211 free_page(tmp);
1212 }
1213 tmp = nr_free_pages << PAGE_SHIFT;
1214 printk("Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data)\n",
1215 tmp >> 10,
1216 high_memory >> 10,
1217 codepages << (PAGE_SHIFT-10),
1218 reservedpages << (PAGE_SHIFT-10),
1219 datapages << (PAGE_SHIFT-10));
1220
1221 wp_works_ok = -1;
1222 pg0[0] = PAGE_READONLY;
1223 invalidate();
1224 __asm__ __volatile__("movb 0,%%al ; movb %%al,0": : :"ax", "memory");
1225 pg0[0] = 0;
1226 invalidate();
1227 if (wp_works_ok < 0)
1228 wp_works_ok = 0;
1229 #ifdef CONFIG_TEST_VERIFY_AREA
1230 wp_works_ok = 0;
1231 #endif
1232 return;
1233 }
1234
1235 void si_meminfo(struct sysinfo *val)
1236 {
1237 int i;
1238
1239 i = high_memory >> PAGE_SHIFT;
1240 val->totalram = 0;
1241 val->sharedram = 0;
1242 val->freeram = nr_free_pages << PAGE_SHIFT;
1243 val->bufferram = buffermem;
1244 while (i-- > 0) {
1245 if (mem_map[i] & MAP_PAGE_RESERVED)
1246 continue;
1247 val->totalram++;
1248 if (!mem_map[i])
1249 continue;
1250 val->sharedram += mem_map[i]-1;
1251 }
1252 val->totalram <<= PAGE_SHIFT;
1253 val->sharedram <<= PAGE_SHIFT;
1254 return;
1255 }
1256
1257
1258
1259 unsigned long file_mmap_nopage(struct vm_area_struct * area, unsigned long address,
1260 unsigned long page, int error_code)
1261 {
1262 struct inode * inode = area->vm_inode;
1263 unsigned int block;
1264 int nr[8];
1265 int i, j;
1266 int prot = area->vm_page_prot;
1267
1268 address &= PAGE_MASK;
1269 block = address - area->vm_start + area->vm_offset;
1270 block >>= inode->i_sb->s_blocksize_bits;
1271
1272 for (i=0, j=0; i< PAGE_SIZE ; j++, block++, i += inode->i_sb->s_blocksize)
1273 nr[j] = bmap(inode,block);
1274 if (error_code & PAGE_RW)
1275 prot |= PAGE_RW | PAGE_DIRTY;
1276 return bread_page(page, inode->i_dev, nr, inode->i_sb->s_blocksize, !(error_code & PAGE_RW));
1277 }
1278
1279 void file_mmap_free(struct vm_area_struct * area)
1280 {
1281 if (area->vm_inode)
1282 iput(area->vm_inode);
1283 #if 0
1284 if (area->vm_inode)
1285 printk("Free inode %x:%d (%d)\n",area->vm_inode->i_dev,
1286 area->vm_inode->i_ino, area->vm_inode->i_count);
1287 #endif
1288 }
1289
1290
1291
1292
1293
1294 int file_mmap_share(struct vm_area_struct * area1,
1295 struct vm_area_struct * area2,
1296 unsigned long address)
1297 {
1298 return 1;
1299 }
1300
1301 struct vm_operations_struct file_mmap = {
1302 NULL,
1303 file_mmap_free,
1304 file_mmap_nopage,
1305 NULL,
1306 file_mmap_share,
1307 NULL,
1308 };