1 /*
2 * address space "slices" (meta-segments) support
3 *
4 * Copyright (C) 2007 Benjamin Herrenschmidt, IBM Corporation.
5 *
6 * Based on hugetlb implementation
7 *
8 * Copyright (C) 2003 David Gibson, IBM Corporation.
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 */
24
25 #undef DEBUG
26
27 #include <linux/kernel.h>
28 #include <linux/mm.h>
29 #include <linux/pagemap.h>
30 #include <linux/err.h>
31 #include <linux/spinlock.h>
32 #include <linux/export.h>
33 #include <linux/hugetlb.h>
34 #include <asm/mman.h>
35 #include <asm/mmu.h>
36 #include <asm/copro.h>
37 #include <asm/hugetlb.h>
38
39 static DEFINE_SPINLOCK(slice_convert_lock);
40 /*
41 * One bit per slice. We have lower slices which cover 256MB segments
42 * upto 4G range. That gets us 16 low slices. For the rest we track slices
43 * in 1TB size.
44 */
45 struct slice_mask {
46 u64 low_slices;
47 DECLARE_BITMAP(high_slices, SLICE_NUM_HIGH);
48 };
49
50 #ifdef DEBUG
51 int _slice_debug = 1;
52
53 static void slice_print_mask(const char *label, struct slice_mask mask)
54 {
55 if (!_slice_debug)
56 return;
57 pr_devel("%s low_slice: %*pbl\n", label, (int)SLICE_NUM_LOW, &mask.low_slices);
58 pr_devel("%s high_slice: %*pbl\n", label, (int)SLICE_NUM_HIGH, mask.high_slices);
59 }
60
61 #define slice_dbg(fmt...) do { if (_slice_debug) pr_devel(fmt); } while (0)
62
63 #else
64
65 static void slice_print_mask(const char *label, struct slice_mask mask) {}
66 #define slice_dbg(fmt...)
67
68 #endif
69
70 static void slice_range_to_mask(unsigned long start, unsigned long len,
71 struct slice_mask *ret)
72 {
73 unsigned long end = start + len - 1;
74
75 ret->low_slices = 0;
76 if (SLICE_NUM_HIGH)
77 bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
78
79 if (start < SLICE_LOW_TOP) {
80 unsigned long mend = min(end,
81 (unsigned long)(SLICE_LOW_TOP - 1));
82
83 ret->low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
84 - (1u << GET_LOW_SLICE_INDEX(start));
85 }
86
87 if ((start + len) > SLICE_LOW_TOP) {
88 unsigned long start_index = GET_HIGH_SLICE_INDEX(start);
89 unsigned long align_end = ALIGN(end, (1UL << SLICE_HIGH_SHIFT));
90 unsigned long count = GET_HIGH_SLICE_INDEX(align_end) - start_index;
91
92 bitmap_set(ret->high_slices, start_index, count);
93 }
94 }
95
96 static int slice_area_is_free(struct mm_struct *mm, unsigned long addr,
97 unsigned long len)
98 {
99 struct vm_area_struct *vma;
100
101 if ((mm->context.slb_addr_limit - len) < addr)
102 return 0;
103 vma = find_vma(mm, addr);
104 return (!vma || (addr + len) <= vm_start_gap(vma));
105 }
106
107 static int slice_low_has_vma(struct mm_struct *mm, unsigned long slice)
108 {
109 return !slice_area_is_free(mm, slice << SLICE_LOW_SHIFT,
110 1ul << SLICE_LOW_SHIFT);
111 }
112
113 static int slice_high_has_vma(struct mm_struct *mm, unsigned long slice)
114 {
115 unsigned long start = slice << SLICE_HIGH_SHIFT;
116 unsigned long end = start + (1ul << SLICE_HIGH_SHIFT);
117
118 #ifdef CONFIG_PPC64
119 /* Hack, so that each addresses is controlled by exactly one
120 * of the high or low area bitmaps, the first high area starts
121 * at 4GB, not 0 */
122 if (start == 0)
123 start = SLICE_LOW_TOP;
124 #endif
125
126 return !slice_area_is_free(mm, start, end - start);
127 }
128
129 static void slice_mask_for_free(struct mm_struct *mm, struct slice_mask *ret,
130 unsigned long high_limit)
131 {
132 unsigned long i;
133
134 ret->low_slices = 0;
135 if (SLICE_NUM_HIGH)
136 bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
137
138 for (i = 0; i < SLICE_NUM_LOW; i++)
139 if (!slice_low_has_vma(mm, i))
140 ret->low_slices |= 1u << i;
141
142 if (high_limit <= SLICE_LOW_TOP)
143 return;
144
145 for (i = 0; i < GET_HIGH_SLICE_INDEX(high_limit); i++)
146 if (!slice_high_has_vma(mm, i))
147 __set_bit(i, ret->high_slices);
148 }
149
150 static void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_mask *ret,
151 unsigned long high_limit)
152 {
153 unsigned char *hpsizes;
154 int index, mask_index;
155 unsigned long i;
156 u64 lpsizes;
157
158 ret->low_slices = 0;
159 if (SLICE_NUM_HIGH)
160 bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
161
162 lpsizes = mm->context.low_slices_psize;
163 for (i = 0; i < SLICE_NUM_LOW; i++)
164 if (((lpsizes >> (i * 4)) & 0xf) == psize)
165 ret->low_slices |= 1u << i;
166
167 if (high_limit <= SLICE_LOW_TOP)
168 return;
169
170 hpsizes = mm->context.high_slices_psize;
171 for (i = 0; i < GET_HIGH_SLICE_INDEX(high_limit); i++) {
172 mask_index = i & 0x1;
173 index = i >> 1;
174 if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == psize)
175 __set_bit(i, ret->high_slices);
176 }
177 }
178
179 static int slice_check_fit(struct mm_struct *mm,
180 struct slice_mask mask, struct slice_mask available)
181 {
182 DECLARE_BITMAP(result, SLICE_NUM_HIGH);
183 /*
184 * Make sure we just do bit compare only to the max
185 * addr limit and not the full bit map size.
186 */
187 unsigned long slice_count = GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit);
188
189 if (!SLICE_NUM_HIGH)
190 return (mask.low_slices & available.low_slices) ==
191 mask.low_slices;
192
193 bitmap_and(result, mask.high_slices,
194 available.high_slices, slice_count);
195
196 return (mask.low_slices & available.low_slices) == mask.low_slices &&
197 bitmap_equal(result, mask.high_slices, slice_count);
198 }
199
200 static void slice_flush_segments(void *parm)
201 {
202 #ifdef CONFIG_PPC64
203 struct mm_struct *mm = parm;
204 unsigned long flags;
205
206 if (mm != current->active_mm)
207 return;
208
209 copy_mm_to_paca(current->active_mm);
210
211 local_irq_save(flags);
212 slb_flush_and_rebolt();
213 local_irq_restore(flags);
214 #endif
215 }
216
217 static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psize)
218 {
219 int index, mask_index;
220 /* Write the new slice psize bits */
221 unsigned char *hpsizes;
222 u64 lpsizes;
223 unsigned long i, flags;
224
225 slice_dbg("slice_convert(mm=%p, psize=%d)\n", mm, psize);
226 slice_print_mask(" mask", mask);
227
228 /* We need to use a spinlock here to protect against
229 * concurrent 64k -> 4k demotion ...
230 */
231 spin_lock_irqsave(&slice_convert_lock, flags);
232
233 lpsizes = mm->context.low_slices_psize;
234 for (i = 0; i < SLICE_NUM_LOW; i++)
235 if (mask.low_slices & (1u << i))
236 lpsizes = (lpsizes & ~(0xful << (i * 4))) |
237 (((unsigned long)psize) << (i * 4));
238
239 /* Assign the value back */
240 mm->context.low_slices_psize = lpsizes;
241
242 hpsizes = mm->context.high_slices_psize;
243 for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit); i++) {
244 mask_index = i & 0x1;
245 index = i >> 1;
246 if (test_bit(i, mask.high_slices))
247 hpsizes[index] = (hpsizes[index] &
248 ~(0xf << (mask_index * 4))) |
249 (((unsigned long)psize) << (mask_index * 4));
250 }
251
252 slice_dbg(" lsps=%lx, hsps=%lx\n",
253 (unsigned long)mm->context.low_slices_psize,
254 (unsigned long)mm->context.high_slices_psize);
255
256 spin_unlock_irqrestore(&slice_convert_lock, flags);
257
258 copro_flush_all_slbs(mm);
259 }
260
261 /*
262 * Compute which slice addr is part of;
263 * set *boundary_addr to the start or end boundary of that slice
264 * (depending on 'end' parameter);
265 * return boolean indicating if the slice is marked as available in the
266 * 'available' slice_mark.
267 */
268 static bool slice_scan_available(unsigned long addr,
269 struct slice_mask available,
270 int end,
271 unsigned long *boundary_addr)
272 {
273 unsigned long slice;
274 if (addr < SLICE_LOW_TOP) {
275 slice = GET_LOW_SLICE_INDEX(addr);
276 *boundary_addr = (slice + end) << SLICE_LOW_SHIFT;
277 return !!(available.low_slices & (1u << slice));
278 } else {
279 slice = GET_HIGH_SLICE_INDEX(addr);
280 *boundary_addr = (slice + end) ?
281 ((slice + end) << SLICE_HIGH_SHIFT) : SLICE_LOW_TOP;
282 return !!test_bit(slice, available.high_slices);
283 }
284 }
285
286 static unsigned long slice_find_area_bottomup(struct mm_struct *mm,
287 unsigned long len,
288 struct slice_mask available,
289 int psize, unsigned long high_limit)
290 {
291 int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
292 unsigned long addr, found, next_end;
293 struct vm_unmapped_area_info info;
294
295 info.flags = 0;
296 info.length = len;
297 info.align_mask = PAGE_MASK & ((1ul << pshift) - 1);
298 info.align_offset = 0;
299
300 addr = TASK_UNMAPPED_BASE;
301 /*
302 * Check till the allow max value for this mmap request
303 */
304 while (addr < high_limit) {
305 info.low_limit = addr;
306 if (!slice_scan_available(addr, available, 1, &addr))
307 continue;
308
309 next_slice:
310 /*
311 * At this point [info.low_limit; addr) covers
312 * available slices only and ends at a slice boundary.
313 * Check if we need to reduce the range, or if we can
314 * extend it to cover the next available slice.
315 */
316 if (addr >= high_limit)
317 addr = high_limit;
318 else if (slice_scan_available(addr, available, 1, &next_end)) {
319 addr = next_end;
320 goto next_slice;
321 }
322 info.high_limit = addr;
323
324 found = vm_unmapped_area(&info);
325 if (!(found & ~PAGE_MASK))
326 return found;
327 }
328
329 return -ENOMEM;
330 }
331
332 static unsigned long slice_find_area_topdown(struct mm_struct *mm,
333 unsigned long len,
334 struct slice_mask available,
335 int psize, unsigned long high_limit)
336 {
337 int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
338 unsigned long addr, found, prev;
339 struct vm_unmapped_area_info info;
340
341 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
342 info.length = len;
343 info.align_mask = PAGE_MASK & ((1ul << pshift) - 1);
344 info.align_offset = 0;
345
346 addr = mm->mmap_base;
347 /*
348 * If we are trying to allocate above DEFAULT_MAP_WINDOW
349 * Add the different to the mmap_base.
350 * Only for that request for which high_limit is above
351 * DEFAULT_MAP_WINDOW we should apply this.
352 */
353 if (high_limit > DEFAULT_MAP_WINDOW)
354 addr += mm->context.slb_addr_limit - DEFAULT_MAP_WINDOW;
355
356 while (addr > PAGE_SIZE) {
357 info.high_limit = addr;
358 if (!slice_scan_available(addr - 1, available, 0, &addr))
359 continue;
360
361 prev_slice:
362 /*
363 * At this point [addr; info.high_limit) covers
364 * available slices only and starts at a slice boundary.
365 * Check if we need to reduce the range, or if we can
366 * extend it to cover the previous available slice.
367 */
368 if (addr < PAGE_SIZE)
369 addr = PAGE_SIZE;
370 else if (slice_scan_available(addr - 1, available, 0, &prev)) {
371 addr = prev;
372 goto prev_slice;
373 }
374 info.low_limit = addr;
375
376 found = vm_unmapped_area(&info);
377 if (!(found & ~PAGE_MASK))
378 return found;
379 }
380
381 /*
382 * A failed mmap() very likely causes application failure,
383 * so fall back to the bottom-up function here. This scenario
384 * can happen with large stack limits and large mmap()
385 * allocations.
386 */
387 return slice_find_area_bottomup(mm, len, available, psize, high_limit);
388 }
389
390
391 static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
392 struct slice_mask mask, int psize,
393 int topdown, unsigned long high_limit)
394 {
395 if (topdown)
396 return slice_find_area_topdown(mm, len, mask, psize, high_limit);
397 else
398 return slice_find_area_bottomup(mm, len, mask, psize, high_limit);
399 }
400
401 static inline void slice_or_mask(struct slice_mask *dst, struct slice_mask *src)
402 {
403 dst->low_slices |= src->low_slices;
404 if (!SLICE_NUM_HIGH)
405 return;
406 bitmap_or(dst->high_slices, dst->high_slices, src->high_slices,
407 SLICE_NUM_HIGH);
408 }
409
410 static inline void slice_andnot_mask(struct slice_mask *dst, struct slice_mask *src)
411 {
412 dst->low_slices &= ~src->low_slices;
413
414 if (!SLICE_NUM_HIGH)
415 return;
416 bitmap_andnot(dst->high_slices, dst->high_slices, src->high_slices,
417 SLICE_NUM_HIGH);
418 }
419
420 #ifdef CONFIG_PPC_64K_PAGES
421 #define MMU_PAGE_BASE MMU_PAGE_64K
422 #else
423 #define MMU_PAGE_BASE MMU_PAGE_4K
424 #endif
425
426 unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
427 unsigned long flags, unsigned int psize,
428 int topdown)
429 {
430 struct slice_mask mask;
431 struct slice_mask good_mask;
432 struct slice_mask potential_mask;
433 struct slice_mask compat_mask;
434 int fixed = (flags & MAP_FIXED);
435 int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
436 unsigned long page_size = 1UL << pshift;
437 struct mm_struct *mm = current->mm;
438 unsigned long newaddr;
439 unsigned long high_limit;
440
441 high_limit = DEFAULT_MAP_WINDOW;
442 if (addr >= high_limit || (fixed && (addr + len > high_limit)))
443 high_limit = TASK_SIZE;
444
445 if (len > high_limit)
446 return -ENOMEM;
447 if (len & (page_size - 1))
448 return -EINVAL;
449 if (fixed) {
450 if (addr & (page_size - 1))
451 return -EINVAL;
452 if (addr > high_limit - len)
453 return -ENOMEM;
454 }
455
456 if (high_limit > mm->context.slb_addr_limit) {
457 mm->context.slb_addr_limit = high_limit;
458 on_each_cpu(slice_flush_segments, mm, 1);
459 }
460
461 /*
462 * init different masks
463 */
464 mask.low_slices = 0;
465
466 /* silence stupid warning */;
467 potential_mask.low_slices = 0;
468
469 compat_mask.low_slices = 0;
470
471 if (SLICE_NUM_HIGH) {
472 bitmap_zero(mask.high_slices, SLICE_NUM_HIGH);
473 bitmap_zero(potential_mask.high_slices, SLICE_NUM_HIGH);
474 bitmap_zero(compat_mask.high_slices, SLICE_NUM_HIGH);
475 }
476
477 /* Sanity checks */
478 BUG_ON(mm->task_size == 0);
479 BUG_ON(mm->context.slb_addr_limit == 0);
480 VM_BUG_ON(radix_enabled());
481
482 slice_dbg("slice_get_unmapped_area(mm=%p, psize=%d...\n", mm, psize);
483 slice_dbg(" addr=%lx, len=%lx, flags=%lx, topdown=%d\n",
484 addr, len, flags, topdown);
485
486 /* If hint, make sure it matches our alignment restrictions */
487 if (!fixed && addr) {
488 addr = _ALIGN_UP(addr, page_size);
489 slice_dbg(" aligned addr=%lx\n", addr);
490 /* Ignore hint if it's too large or overlaps a VMA */
491 if (addr > high_limit - len ||
492 !slice_area_is_free(mm, addr, len))
493 addr = 0;
494 }
495
496 /* First make up a "good" mask of slices that have the right size
497 * already
498 */
499 slice_mask_for_size(mm, psize, &good_mask, high_limit);
500 slice_print_mask(" good_mask", good_mask);
501
502 /*
503 * Here "good" means slices that are already the right page size,
504 * "compat" means slices that have a compatible page size (i.e.
505 * 4k in a 64k pagesize kernel), and "free" means slices without
506 * any VMAs.
507 *
508 * If MAP_FIXED:
509 * check if fits in good | compat => OK
510 * check if fits in good | compat | free => convert free
511 * else bad
512 * If have hint:
513 * check if hint fits in good => OK
514 * check if hint fits in good | free => convert free
515 * Otherwise:
516 * search in good, found => OK
517 * search in good | free, found => convert free
518 * search in good | compat | free, found => convert free.
519 */
520
521 #ifdef CONFIG_PPC_64K_PAGES
522 /* If we support combo pages, we can allow 64k pages in 4k slices */
523 if (psize == MMU_PAGE_64K) {
524 slice_mask_for_size(mm, MMU_PAGE_4K, &compat_mask, high_limit);
525 if (fixed)
526 slice_or_mask(&good_mask, &compat_mask);
527 }
528 #endif
529
530 /* First check hint if it's valid or if we have MAP_FIXED */
531 if (addr != 0 || fixed) {
532 /* Build a mask for the requested range */
533 slice_range_to_mask(addr, len, &mask);
534 slice_print_mask(" mask", mask);
535
536 /* Check if we fit in the good mask. If we do, we just return,
537 * nothing else to do
538 */
539 if (slice_check_fit(mm, mask, good_mask)) {
540 slice_dbg(" fits good !\n");
541 return addr;
542 }
543 } else {
544 /* Now let's see if we can find something in the existing
545 * slices for that size
546 */
547 newaddr = slice_find_area(mm, len, good_mask,
548 psize, topdown, high_limit);
549 if (newaddr != -ENOMEM) {
550 /* Found within the good mask, we don't have to setup,
551 * we thus return directly
552 */
553 slice_dbg(" found area at 0x%lx\n", newaddr);
554 return newaddr;
555 }
556 }
557 /*
558 * We don't fit in the good mask, check what other slices are
559 * empty and thus can be converted
560 */
561 slice_mask_for_free(mm, &potential_mask, high_limit);
562 slice_or_mask(&potential_mask, &good_mask);
563 slice_print_mask(" potential", potential_mask);
564
565 if ((addr != 0 || fixed) && slice_check_fit(mm, mask, potential_mask)) {
566 slice_dbg(" fits potential !\n");
567 goto convert;
568 }
569
570 /* If we have MAP_FIXED and failed the above steps, then error out */
571 if (fixed)
572 return -EBUSY;
573
574 slice_dbg(" search...\n");
575
576 /* If we had a hint that didn't work out, see if we can fit
577 * anywhere in the good area.
578 */
579 if (addr) {
580 addr = slice_find_area(mm, len, good_mask,
581 psize, topdown, high_limit);
582 if (addr != -ENOMEM) {
583 slice_dbg(" found area at 0x%lx\n", addr);
584 return addr;
585 }
586 }
587
588 /* Now let's see if we can find something in the existing slices
589 * for that size plus free slices
590 */
591 addr = slice_find_area(mm, len, potential_mask,
592 psize, topdown, high_limit);
593
594 #ifdef CONFIG_PPC_64K_PAGES
595 if (addr == -ENOMEM && psize == MMU_PAGE_64K) {
596 /* retry the search with 4k-page slices included */
597 slice_or_mask(&potential_mask, &compat_mask);
598 addr = slice_find_area(mm, len, potential_mask,
599 psize, topdown, high_limit);
600 }
601 #endif
602
603 if (addr == -ENOMEM)
604 return -ENOMEM;
605
606 slice_range_to_mask(addr, len, &mask);
607 slice_dbg(" found potential area at 0x%lx\n", addr);
608 slice_print_mask(" mask", mask);
609
610 convert:
611 slice_andnot_mask(&mask, &good_mask);
612 slice_andnot_mask(&mask, &compat_mask);
613 if (mask.low_slices ||
614 (SLICE_NUM_HIGH &&
615 !bitmap_empty(mask.high_slices, SLICE_NUM_HIGH))) {
616 slice_convert(mm, mask, psize);
617 if (psize > MMU_PAGE_BASE)
618 on_each_cpu(slice_flush_segments, mm, 1);
619 }
620 return addr;
621
622 }
623 EXPORT_SYMBOL_GPL(slice_get_unmapped_area);
624
625 unsigned long arch_get_unmapped_area(struct file *filp,
626 unsigned long addr,
627 unsigned long len,
628 unsigned long pgoff,
629 unsigned long flags)
630 {
631 return slice_get_unmapped_area(addr, len, flags,
632 current->mm->context.user_psize, 0);
633 }
634
635 unsigned long arch_get_unmapped_area_topdown(struct file *filp,
636 const unsigned long addr0,
637 const unsigned long len,
638 const unsigned long pgoff,
639 const unsigned long flags)
640 {
641 return slice_get_unmapped_area(addr0, len, flags,
642 current->mm->context.user_psize, 1);
643 }
644
645 unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr)
646 {
647 unsigned char *hpsizes;
648 int index, mask_index;
649
650 /*
651 * Radix doesn't use slice, but can get enabled along with MMU_SLICE
652 */
653 if (radix_enabled()) {
654 #ifdef CONFIG_PPC_64K_PAGES
655 return MMU_PAGE_64K;
656 #else
657 return MMU_PAGE_4K;
658 #endif
659 }
660 if (addr < SLICE_LOW_TOP) {
661 u64 lpsizes;
662 lpsizes = mm->context.low_slices_psize;
663 index = GET_LOW_SLICE_INDEX(addr);
664 return (lpsizes >> (index * 4)) & 0xf;
665 }
666 hpsizes = mm->context.high_slices_psize;
667 index = GET_HIGH_SLICE_INDEX(addr);
668 mask_index = index & 0x1;
669 return (hpsizes[index >> 1] >> (mask_index * 4)) & 0xf;
670 }
671 EXPORT_SYMBOL_GPL(get_slice_psize);
672
673 /*
674 * This is called by hash_page when it needs to do a lazy conversion of
675 * an address space from real 64K pages to combo 4K pages (typically
676 * when hitting a non cacheable mapping on a processor or hypervisor
677 * that won't allow them for 64K pages).
678 *
679 * This is also called in init_new_context() to change back the user
680 * psize from whatever the parent context had it set to
681 * N.B. This may be called before mm->context.id has been set.
682 *
683 * This function will only change the content of the {low,high)_slice_psize
684 * masks, it will not flush SLBs as this shall be handled lazily by the
685 * caller.
686 */
687 void slice_set_user_psize(struct mm_struct *mm, unsigned int psize)
688 {
689 int index, mask_index;
690 unsigned char *hpsizes;
691 unsigned long flags, lpsizes;
692 unsigned int old_psize;
693 int i;
694
695 slice_dbg("slice_set_user_psize(mm=%p, psize=%d)\n", mm, psize);
696
697 VM_BUG_ON(radix_enabled());
698 spin_lock_irqsave(&slice_convert_lock, flags);
699
700 old_psize = mm->context.user_psize;
701 slice_dbg(" old_psize=%d\n", old_psize);
702 if (old_psize == psize)
703 goto bail;
704
705 mm->context.user_psize = psize;
706 wmb();
707
708 lpsizes = mm->context.low_slices_psize;
709 for (i = 0; i < SLICE_NUM_LOW; i++)
710 if (((lpsizes >> (i * 4)) & 0xf) == old_psize)
711 lpsizes = (lpsizes & ~(0xful << (i * 4))) |
712 (((unsigned long)psize) << (i * 4));
713 /* Assign the value back */
714 mm->context.low_slices_psize = lpsizes;
715
716 hpsizes = mm->context.high_slices_psize;
717 for (i = 0; i < SLICE_NUM_HIGH; i++) {
718 mask_index = i & 0x1;
719 index = i >> 1;
720 if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == old_psize)
721 hpsizes[index] = (hpsizes[index] &
722 ~(0xf << (mask_index * 4))) |
723 (((unsigned long)psize) << (mask_index * 4));
724 }
725
726
727
728
729 slice_dbg(" lsps=%lx, hsps=%lx\n",
730 (unsigned long)mm->context.low_slices_psize,
731 (unsigned long)mm->context.high_slices_psize);
732
733 bail:
734 spin_unlock_irqrestore(&slice_convert_lock, flags);
735 }
736
737 void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
738 unsigned long len, unsigned int psize)
739 {
740 struct slice_mask mask;
741
742 VM_BUG_ON(radix_enabled());
743
744 slice_range_to_mask(start, len, &mask);
745 slice_convert(mm, mask, psize);
746 }
747
748 #ifdef CONFIG_HUGETLB_PAGE
749 /*
750 * is_hugepage_only_range() is used by generic code to verify whether
751 * a normal mmap mapping (non hugetlbfs) is valid on a given area.
752 *
753 * until the generic code provides a more generic hook and/or starts
754 * calling arch get_unmapped_area for MAP_FIXED (which our implementation
755 * here knows how to deal with), we hijack it to keep standard mappings
756 * away from us.
757 *
758 * because of that generic code limitation, MAP_FIXED mapping cannot
759 * "convert" back a slice with no VMAs to the standard page size, only
760 * get_unmapped_area() can. It would be possible to fix it here but I
761 * prefer working on fixing the generic code instead.
762 *
763 * WARNING: This will not work if hugetlbfs isn't enabled since the
764 * generic code will redefine that function as 0 in that. This is ok
765 * for now as we only use slices with hugetlbfs enabled. This should
766 * be fixed as the generic code gets fixed.
767 */
768 int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
769 unsigned long len)
770 {
771 struct slice_mask mask, available;
772 unsigned int psize = mm->context.user_psize;
773 unsigned long high_limit = mm->context.slb_addr_limit;
774
775 if (radix_enabled())
776 return 0;
777
778 slice_range_to_mask(addr, len, &mask);
779 slice_mask_for_size(mm, psize, &available, high_limit);
780 #ifdef CONFIG_PPC_64K_PAGES
781 /* We need to account for 4k slices too */
782 if (psize == MMU_PAGE_64K) {
783 struct slice_mask compat_mask;
784 slice_mask_for_size(mm, MMU_PAGE_4K, &compat_mask, high_limit);
785 slice_or_mask(&available, &compat_mask);
786 }
787 #endif
788
789 #if 0 /* too verbose */
790 slice_dbg("is_hugepage_only_range(mm=%p, addr=%lx, len=%lx)\n",
791 mm, addr, len);
792 slice_print_mask(" mask", mask);
793 slice_print_mask(" available", available);
794 #endif
795 return !slice_check_fit(mm, mask, available);
796 }
797 #endif
798
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