2 * address space "slices" (meta-segments) support
4 * Copyright (C) 2007 Benjamin Herrenschmidt, IBM Corporation.
6 * Based on hugetlb implementation
8 * Copyright (C) 2003 David Gibson, IBM Corporation.
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.
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.
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
27 #include <linux/kernel.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 <linux/security.h>
37 #include <asm/copro.h>
38 #include <asm/hugetlb.h>
39 #include <asm/mmu_context.h>
41 static DEFINE_SPINLOCK(slice_convert_lock);
46 static void slice_print_mask(const char *label, const struct slice_mask *mask)
50 pr_devel("%s low_slice: %*pbl\n", label,
51 (int)SLICE_NUM_LOW, &mask->low_slices);
52 pr_devel("%s high_slice: %*pbl\n", label,
53 (int)SLICE_NUM_HIGH, mask->high_slices);
56 #define slice_dbg(fmt...) do { if (_slice_debug) pr_devel(fmt); } while (0)
60 static void slice_print_mask(const char *label, const struct slice_mask *mask) {}
61 #define slice_dbg(fmt...)
65 static inline bool slice_addr_is_low(unsigned long addr)
69 return tmp < SLICE_LOW_TOP;
72 static void slice_range_to_mask(unsigned long start, unsigned long len,
73 struct slice_mask *ret)
75 unsigned long end = start + len - 1;
79 bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
81 if (slice_addr_is_low(start)) {
82 unsigned long mend = min(end,
83 (unsigned long)(SLICE_LOW_TOP - 1));
85 ret->low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
86 - (1u << GET_LOW_SLICE_INDEX(start));
89 if (SLICE_NUM_HIGH && !slice_addr_is_low(end)) {
90 unsigned long start_index = GET_HIGH_SLICE_INDEX(start);
91 unsigned long align_end = ALIGN(end, (1UL << SLICE_HIGH_SHIFT));
92 unsigned long count = GET_HIGH_SLICE_INDEX(align_end) - start_index;
94 bitmap_set(ret->high_slices, start_index, count);
98 static int slice_area_is_free(struct mm_struct *mm, unsigned long addr,
101 struct vm_area_struct *vma;
103 if ((mm->context.slb_addr_limit - len) < addr)
105 vma = find_vma(mm, addr);
106 return (!vma || (addr + len) <= vm_start_gap(vma));
109 static int slice_low_has_vma(struct mm_struct *mm, unsigned long slice)
111 return !slice_area_is_free(mm, slice << SLICE_LOW_SHIFT,
112 1ul << SLICE_LOW_SHIFT);
115 static int slice_high_has_vma(struct mm_struct *mm, unsigned long slice)
117 unsigned long start = slice << SLICE_HIGH_SHIFT;
118 unsigned long end = start + (1ul << SLICE_HIGH_SHIFT);
121 /* Hack, so that each addresses is controlled by exactly one
122 * of the high or low area bitmaps, the first high area starts
125 start = SLICE_LOW_TOP;
128 return !slice_area_is_free(mm, start, end - start);
131 static void slice_mask_for_free(struct mm_struct *mm, struct slice_mask *ret,
132 unsigned long high_limit)
138 bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
140 for (i = 0; i < SLICE_NUM_LOW; i++)
141 if (!slice_low_has_vma(mm, i))
142 ret->low_slices |= 1u << i;
144 if (slice_addr_is_low(high_limit - 1))
147 for (i = 0; i < GET_HIGH_SLICE_INDEX(high_limit); i++)
148 if (!slice_high_has_vma(mm, i))
149 __set_bit(i, ret->high_slices);
152 #ifdef CONFIG_PPC_BOOK3S_64
153 static struct slice_mask *slice_mask_for_size(struct mm_struct *mm, int psize)
155 #ifdef CONFIG_PPC_64K_PAGES
156 if (psize == MMU_PAGE_64K)
157 return &mm->context.mask_64k;
159 if (psize == MMU_PAGE_4K)
160 return &mm->context.mask_4k;
161 #ifdef CONFIG_HUGETLB_PAGE
162 if (psize == MMU_PAGE_16M)
163 return &mm->context.mask_16m;
164 if (psize == MMU_PAGE_16G)
165 return &mm->context.mask_16g;
169 #elif defined(CONFIG_PPC_8xx)
170 static struct slice_mask *slice_mask_for_size(struct mm_struct *mm, int psize)
172 if (psize == mmu_virtual_psize)
173 return &mm->context.mask_base_psize;
174 #ifdef CONFIG_HUGETLB_PAGE
175 if (psize == MMU_PAGE_512K)
176 return &mm->context.mask_512k;
177 if (psize == MMU_PAGE_8M)
178 return &mm->context.mask_8m;
183 #error "Must define the slice masks for page sizes supported by the platform"
186 static bool slice_check_range_fits(struct mm_struct *mm,
187 const struct slice_mask *available,
188 unsigned long start, unsigned long len)
190 unsigned long end = start + len - 1;
193 if (slice_addr_is_low(start)) {
194 unsigned long mend = min(end,
195 (unsigned long)(SLICE_LOW_TOP - 1));
197 low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
198 - (1u << GET_LOW_SLICE_INDEX(start));
200 if ((low_slices & available->low_slices) != low_slices)
203 if (SLICE_NUM_HIGH && !slice_addr_is_low(end)) {
204 unsigned long start_index = GET_HIGH_SLICE_INDEX(start);
205 unsigned long align_end = ALIGN(end, (1UL << SLICE_HIGH_SHIFT));
206 unsigned long count = GET_HIGH_SLICE_INDEX(align_end) - start_index;
209 for (i = start_index; i < start_index + count; i++) {
210 if (!test_bit(i, available->high_slices))
218 static void slice_flush_segments(void *parm)
221 struct mm_struct *mm = parm;
224 if (mm != current->active_mm)
227 copy_mm_to_paca(current->active_mm);
229 local_irq_save(flags);
230 slb_flush_and_rebolt();
231 local_irq_restore(flags);
235 static void slice_convert(struct mm_struct *mm,
236 const struct slice_mask *mask, int psize)
238 int index, mask_index;
239 /* Write the new slice psize bits */
240 unsigned char *hpsizes, *lpsizes;
241 struct slice_mask *psize_mask, *old_mask;
242 unsigned long i, flags;
245 slice_dbg("slice_convert(mm=%p, psize=%d)\n", mm, psize);
246 slice_print_mask(" mask", mask);
248 psize_mask = slice_mask_for_size(mm, psize);
250 /* We need to use a spinlock here to protect against
251 * concurrent 64k -> 4k demotion ...
253 spin_lock_irqsave(&slice_convert_lock, flags);
255 lpsizes = mm->context.low_slices_psize;
256 for (i = 0; i < SLICE_NUM_LOW; i++) {
257 if (!(mask->low_slices & (1u << i)))
260 mask_index = i & 0x1;
263 /* Update the slice_mask */
264 old_psize = (lpsizes[index] >> (mask_index * 4)) & 0xf;
265 old_mask = slice_mask_for_size(mm, old_psize);
266 old_mask->low_slices &= ~(1u << i);
267 psize_mask->low_slices |= 1u << i;
269 /* Update the sizes array */
270 lpsizes[index] = (lpsizes[index] & ~(0xf << (mask_index * 4))) |
271 (((unsigned long)psize) << (mask_index * 4));
274 hpsizes = mm->context.high_slices_psize;
275 for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit); i++) {
276 if (!test_bit(i, mask->high_slices))
279 mask_index = i & 0x1;
282 /* Update the slice_mask */
283 old_psize = (hpsizes[index] >> (mask_index * 4)) & 0xf;
284 old_mask = slice_mask_for_size(mm, old_psize);
285 __clear_bit(i, old_mask->high_slices);
286 __set_bit(i, psize_mask->high_slices);
288 /* Update the sizes array */
289 hpsizes[index] = (hpsizes[index] & ~(0xf << (mask_index * 4))) |
290 (((unsigned long)psize) << (mask_index * 4));
293 slice_dbg(" lsps=%lx, hsps=%lx\n",
294 (unsigned long)mm->context.low_slices_psize,
295 (unsigned long)mm->context.high_slices_psize);
297 spin_unlock_irqrestore(&slice_convert_lock, flags);
299 copro_flush_all_slbs(mm);
303 * Compute which slice addr is part of;
304 * set *boundary_addr to the start or end boundary of that slice
305 * (depending on 'end' parameter);
306 * return boolean indicating if the slice is marked as available in the
307 * 'available' slice_mark.
309 static bool slice_scan_available(unsigned long addr,
310 const struct slice_mask *available,
311 int end, unsigned long *boundary_addr)
314 if (slice_addr_is_low(addr)) {
315 slice = GET_LOW_SLICE_INDEX(addr);
316 *boundary_addr = (slice + end) << SLICE_LOW_SHIFT;
317 return !!(available->low_slices & (1u << slice));
319 slice = GET_HIGH_SLICE_INDEX(addr);
320 *boundary_addr = (slice + end) ?
321 ((slice + end) << SLICE_HIGH_SHIFT) : SLICE_LOW_TOP;
322 return !!test_bit(slice, available->high_slices);
326 static unsigned long slice_find_area_bottomup(struct mm_struct *mm,
328 const struct slice_mask *available,
329 int psize, unsigned long high_limit)
331 int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
332 unsigned long addr, found, next_end;
333 struct vm_unmapped_area_info info;
337 info.align_mask = PAGE_MASK & ((1ul << pshift) - 1);
338 info.align_offset = 0;
340 addr = TASK_UNMAPPED_BASE;
342 * Check till the allow max value for this mmap request
344 while (addr < high_limit) {
345 info.low_limit = addr;
346 if (!slice_scan_available(addr, available, 1, &addr))
351 * At this point [info.low_limit; addr) covers
352 * available slices only and ends at a slice boundary.
353 * Check if we need to reduce the range, or if we can
354 * extend it to cover the next available slice.
356 if (addr >= high_limit)
358 else if (slice_scan_available(addr, available, 1, &next_end)) {
362 info.high_limit = addr;
364 found = vm_unmapped_area(&info);
365 if (!(found & ~PAGE_MASK))
372 static unsigned long slice_find_area_topdown(struct mm_struct *mm,
374 const struct slice_mask *available,
375 int psize, unsigned long high_limit)
377 int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
378 unsigned long addr, found, prev;
379 struct vm_unmapped_area_info info;
380 unsigned long min_addr = max(PAGE_SIZE, mmap_min_addr);
382 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
384 info.align_mask = PAGE_MASK & ((1ul << pshift) - 1);
385 info.align_offset = 0;
387 addr = mm->mmap_base;
389 * If we are trying to allocate above DEFAULT_MAP_WINDOW
390 * Add the different to the mmap_base.
391 * Only for that request for which high_limit is above
392 * DEFAULT_MAP_WINDOW we should apply this.
394 if (high_limit > DEFAULT_MAP_WINDOW)
395 addr += mm->context.slb_addr_limit - DEFAULT_MAP_WINDOW;
397 while (addr > min_addr) {
398 info.high_limit = addr;
399 if (!slice_scan_available(addr - 1, available, 0, &addr))
404 * At this point [addr; info.high_limit) covers
405 * available slices only and starts at a slice boundary.
406 * Check if we need to reduce the range, or if we can
407 * extend it to cover the previous available slice.
411 else if (slice_scan_available(addr - 1, available, 0, &prev)) {
415 info.low_limit = addr;
417 found = vm_unmapped_area(&info);
418 if (!(found & ~PAGE_MASK))
423 * A failed mmap() very likely causes application failure,
424 * so fall back to the bottom-up function here. This scenario
425 * can happen with large stack limits and large mmap()
428 return slice_find_area_bottomup(mm, len, available, psize, high_limit);
432 static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
433 const struct slice_mask *mask, int psize,
434 int topdown, unsigned long high_limit)
437 return slice_find_area_topdown(mm, len, mask, psize, high_limit);
439 return slice_find_area_bottomup(mm, len, mask, psize, high_limit);
442 static inline void slice_copy_mask(struct slice_mask *dst,
443 const struct slice_mask *src)
445 dst->low_slices = src->low_slices;
448 bitmap_copy(dst->high_slices, src->high_slices, SLICE_NUM_HIGH);
451 static inline void slice_or_mask(struct slice_mask *dst,
452 const struct slice_mask *src1,
453 const struct slice_mask *src2)
455 dst->low_slices = src1->low_slices | src2->low_slices;
458 bitmap_or(dst->high_slices, src1->high_slices, src2->high_slices, SLICE_NUM_HIGH);
461 static inline void slice_andnot_mask(struct slice_mask *dst,
462 const struct slice_mask *src1,
463 const struct slice_mask *src2)
465 dst->low_slices = src1->low_slices & ~src2->low_slices;
468 bitmap_andnot(dst->high_slices, src1->high_slices, src2->high_slices, SLICE_NUM_HIGH);
471 #ifdef CONFIG_PPC_64K_PAGES
472 #define MMU_PAGE_BASE MMU_PAGE_64K
474 #define MMU_PAGE_BASE MMU_PAGE_4K
477 unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
478 unsigned long flags, unsigned int psize,
481 struct slice_mask good_mask;
482 struct slice_mask potential_mask;
483 const struct slice_mask *maskp;
484 const struct slice_mask *compat_maskp = NULL;
485 int fixed = (flags & MAP_FIXED);
486 int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
487 unsigned long page_size = 1UL << pshift;
488 struct mm_struct *mm = current->mm;
489 unsigned long newaddr;
490 unsigned long high_limit;
492 high_limit = DEFAULT_MAP_WINDOW;
493 if (addr >= high_limit || (fixed && (addr + len > high_limit)))
494 high_limit = TASK_SIZE;
496 if (len > high_limit)
498 if (len & (page_size - 1))
501 if (addr & (page_size - 1))
503 if (addr > high_limit - len)
507 if (high_limit > mm->context.slb_addr_limit) {
509 * Increasing the slb_addr_limit does not require
510 * slice mask cache to be recalculated because it should
511 * be already initialised beyond the old address limit.
513 mm->context.slb_addr_limit = high_limit;
515 on_each_cpu(slice_flush_segments, mm, 1);
519 BUG_ON(mm->task_size == 0);
520 BUG_ON(mm->context.slb_addr_limit == 0);
521 VM_BUG_ON(radix_enabled());
523 slice_dbg("slice_get_unmapped_area(mm=%p, psize=%d...\n", mm, psize);
524 slice_dbg(" addr=%lx, len=%lx, flags=%lx, topdown=%d\n",
525 addr, len, flags, topdown);
527 /* If hint, make sure it matches our alignment restrictions */
528 if (!fixed && addr) {
529 addr = _ALIGN_UP(addr, page_size);
530 slice_dbg(" aligned addr=%lx\n", addr);
531 /* Ignore hint if it's too large or overlaps a VMA */
532 if (addr > high_limit - len || addr < mmap_min_addr ||
533 !slice_area_is_free(mm, addr, len))
537 /* First make up a "good" mask of slices that have the right size
540 maskp = slice_mask_for_size(mm, psize);
543 * Here "good" means slices that are already the right page size,
544 * "compat" means slices that have a compatible page size (i.e.
545 * 4k in a 64k pagesize kernel), and "free" means slices without
549 * check if fits in good | compat => OK
550 * check if fits in good | compat | free => convert free
553 * check if hint fits in good => OK
554 * check if hint fits in good | free => convert free
556 * search in good, found => OK
557 * search in good | free, found => convert free
558 * search in good | compat | free, found => convert free.
562 * If we support combo pages, we can allow 64k pages in 4k slices
563 * The mask copies could be avoided in most cases here if we had
564 * a pointer to good mask for the next code to use.
566 if (IS_ENABLED(CONFIG_PPC_64K_PAGES) && psize == MMU_PAGE_64K) {
567 compat_maskp = slice_mask_for_size(mm, MMU_PAGE_4K);
569 slice_or_mask(&good_mask, maskp, compat_maskp);
571 slice_copy_mask(&good_mask, maskp);
573 slice_copy_mask(&good_mask, maskp);
576 slice_print_mask(" good_mask", &good_mask);
578 slice_print_mask(" compat_mask", compat_maskp);
580 /* First check hint if it's valid or if we have MAP_FIXED */
581 if (addr != 0 || fixed) {
582 /* Check if we fit in the good mask. If we do, we just return,
585 if (slice_check_range_fits(mm, &good_mask, addr, len)) {
586 slice_dbg(" fits good !\n");
591 /* Now let's see if we can find something in the existing
592 * slices for that size
594 newaddr = slice_find_area(mm, len, &good_mask,
595 psize, topdown, high_limit);
596 if (newaddr != -ENOMEM) {
597 /* Found within the good mask, we don't have to setup,
598 * we thus return directly
600 slice_dbg(" found area at 0x%lx\n", newaddr);
605 * We don't fit in the good mask, check what other slices are
606 * empty and thus can be converted
608 slice_mask_for_free(mm, &potential_mask, high_limit);
609 slice_or_mask(&potential_mask, &potential_mask, &good_mask);
610 slice_print_mask(" potential", &potential_mask);
612 if (addr != 0 || fixed) {
613 if (slice_check_range_fits(mm, &potential_mask, addr, len)) {
614 slice_dbg(" fits potential !\n");
620 /* If we have MAP_FIXED and failed the above steps, then error out */
624 slice_dbg(" search...\n");
626 /* If we had a hint that didn't work out, see if we can fit
627 * anywhere in the good area.
630 newaddr = slice_find_area(mm, len, &good_mask,
631 psize, topdown, high_limit);
632 if (newaddr != -ENOMEM) {
633 slice_dbg(" found area at 0x%lx\n", newaddr);
638 /* Now let's see if we can find something in the existing slices
639 * for that size plus free slices
641 newaddr = slice_find_area(mm, len, &potential_mask,
642 psize, topdown, high_limit);
644 #ifdef CONFIG_PPC_64K_PAGES
645 if (newaddr == -ENOMEM && psize == MMU_PAGE_64K) {
646 /* retry the search with 4k-page slices included */
647 slice_or_mask(&potential_mask, &potential_mask, compat_maskp);
648 newaddr = slice_find_area(mm, len, &potential_mask,
649 psize, topdown, high_limit);
653 if (newaddr == -ENOMEM)
656 slice_range_to_mask(newaddr, len, &potential_mask);
657 slice_dbg(" found potential area at 0x%lx\n", newaddr);
658 slice_print_mask(" mask", &potential_mask);
662 * Try to allocate the context before we do slice convert
663 * so that we handle the context allocation failure gracefully.
665 if (need_extra_context(mm, newaddr)) {
666 if (alloc_extended_context(mm, newaddr) < 0)
670 slice_andnot_mask(&potential_mask, &potential_mask, &good_mask);
671 if (compat_maskp && !fixed)
672 slice_andnot_mask(&potential_mask, &potential_mask, compat_maskp);
673 if (potential_mask.low_slices ||
675 !bitmap_empty(potential_mask.high_slices, SLICE_NUM_HIGH))) {
676 slice_convert(mm, &potential_mask, psize);
677 if (psize > MMU_PAGE_BASE)
678 on_each_cpu(slice_flush_segments, mm, 1);
683 if (need_extra_context(mm, newaddr)) {
684 if (alloc_extended_context(mm, newaddr) < 0)
689 EXPORT_SYMBOL_GPL(slice_get_unmapped_area);
691 unsigned long arch_get_unmapped_area(struct file *filp,
697 return slice_get_unmapped_area(addr, len, flags,
698 current->mm->context.user_psize, 0);
701 unsigned long arch_get_unmapped_area_topdown(struct file *filp,
702 const unsigned long addr0,
703 const unsigned long len,
704 const unsigned long pgoff,
705 const unsigned long flags)
707 return slice_get_unmapped_area(addr0, len, flags,
708 current->mm->context.user_psize, 1);
711 unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr)
713 unsigned char *psizes;
714 int index, mask_index;
716 VM_BUG_ON(radix_enabled());
718 if (slice_addr_is_low(addr)) {
719 psizes = mm->context.low_slices_psize;
720 index = GET_LOW_SLICE_INDEX(addr);
722 psizes = mm->context.high_slices_psize;
723 index = GET_HIGH_SLICE_INDEX(addr);
725 mask_index = index & 0x1;
726 return (psizes[index >> 1] >> (mask_index * 4)) & 0xf;
728 EXPORT_SYMBOL_GPL(get_slice_psize);
730 void slice_init_new_context_exec(struct mm_struct *mm)
732 unsigned char *hpsizes, *lpsizes;
733 struct slice_mask *mask;
734 unsigned int psize = mmu_virtual_psize;
736 slice_dbg("slice_init_new_context_exec(mm=%p)\n", mm);
739 * In the case of exec, use the default limit. In the
740 * case of fork it is just inherited from the mm being
744 mm->context.slb_addr_limit = DEFAULT_MAP_WINDOW_USER64;
746 mm->context.slb_addr_limit = DEFAULT_MAP_WINDOW;
749 mm->context.user_psize = psize;
752 * Set all slice psizes to the default.
754 lpsizes = mm->context.low_slices_psize;
755 memset(lpsizes, (psize << 4) | psize, SLICE_NUM_LOW >> 1);
757 hpsizes = mm->context.high_slices_psize;
758 memset(hpsizes, (psize << 4) | psize, SLICE_NUM_HIGH >> 1);
761 * Slice mask cache starts zeroed, fill the default size cache.
763 mask = slice_mask_for_size(mm, psize);
764 mask->low_slices = ~0UL;
766 bitmap_fill(mask->high_slices, SLICE_NUM_HIGH);
769 void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
770 unsigned long len, unsigned int psize)
772 struct slice_mask mask;
774 VM_BUG_ON(radix_enabled());
776 slice_range_to_mask(start, len, &mask);
777 slice_convert(mm, &mask, psize);
780 #ifdef CONFIG_HUGETLB_PAGE
782 * is_hugepage_only_range() is used by generic code to verify whether
783 * a normal mmap mapping (non hugetlbfs) is valid on a given area.
785 * until the generic code provides a more generic hook and/or starts
786 * calling arch get_unmapped_area for MAP_FIXED (which our implementation
787 * here knows how to deal with), we hijack it to keep standard mappings
790 * because of that generic code limitation, MAP_FIXED mapping cannot
791 * "convert" back a slice with no VMAs to the standard page size, only
792 * get_unmapped_area() can. It would be possible to fix it here but I
793 * prefer working on fixing the generic code instead.
795 * WARNING: This will not work if hugetlbfs isn't enabled since the
796 * generic code will redefine that function as 0 in that. This is ok
797 * for now as we only use slices with hugetlbfs enabled. This should
798 * be fixed as the generic code gets fixed.
800 int slice_is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
803 const struct slice_mask *maskp;
804 unsigned int psize = mm->context.user_psize;
806 VM_BUG_ON(radix_enabled());
808 maskp = slice_mask_for_size(mm, psize);
809 #ifdef CONFIG_PPC_64K_PAGES
810 /* We need to account for 4k slices too */
811 if (psize == MMU_PAGE_64K) {
812 const struct slice_mask *compat_maskp;
813 struct slice_mask available;
815 compat_maskp = slice_mask_for_size(mm, MMU_PAGE_4K);
816 slice_or_mask(&available, maskp, compat_maskp);
817 return !slice_check_range_fits(mm, &available, addr, len);
821 return !slice_check_range_fits(mm, maskp, addr, len);