1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * address space "slices" (meta-segments) support
4 *
5 * Copyright (C) 2007 Benjamin Herrenschmidt, IBM Corporation.
6 *
7 * Based on hugetlb implementation
8 *
9 * Copyright (C) 2003 David Gibson, IBM Corporation.
10 */
11
12 #undef DEBUG
13
14 #include <linux/kernel.h>
15 #include <linux/mm.h>
16 #include <linux/pagemap.h>
17 #include <linux/err.h>
18 #include <linux/spinlock.h>
19 #include <linux/export.h>
20 #include <linux/hugetlb.h>
21 #include <linux/sched/mm.h>
22 #include <linux/security.h>
23 #include <asm/mman.h>
24 #include <asm/mmu.h>
25 #include <asm/copro.h>
26 #include <asm/hugetlb.h>
27 #include <asm/mmu_context.h>
28
29 static DEFINE_SPINLOCK(slice_convert_lock);
30
31 #ifdef DEBUG
32 int _slice_debug = 1;
33
34 static void slice_print_mask(const char *label, const struct slice_mask *mask)
35 {
36 if (!_slice_debug)
37 return;
38 pr_devel("%s low_slice: %*pbl\n", label,
39 (int)SLICE_NUM_LOW, &mask->low_slices);
40 pr_devel("%s high_slice: %*pbl\n", label,
41 (int)SLICE_NUM_HIGH, mask->high_slices);
42 }
43
44 #define slice_dbg(fmt...) do { if (_slice_debug) pr_devel(fmt); } while (0)
45
46 #else
47
48 static void slice_print_mask(const char *label, const struct slice_mask *mask) {}
49 #define slice_dbg(fmt...)
50
51 #endif
52
53 static inline notrace bool slice_addr_is_low(unsigned long addr)
54 {
55 u64 tmp = (u64)addr;
56
57 return tmp < SLICE_LOW_TOP;
58 }
59
60 static void slice_range_to_mask(unsigned long start, unsigned long len,
61 struct slice_mask *ret)
62 {
63 unsigned long end = start + len - 1;
64
65 ret->low_slices = 0;
66 if (SLICE_NUM_HIGH)
67 bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
68
69 if (slice_addr_is_low(start)) {
70 unsigned long mend = min(end,
71 (unsigned long)(SLICE_LOW_TOP - 1));
72
73 ret->low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
74 - (1u << GET_LOW_SLICE_INDEX(start));
75 }
76
77 if (SLICE_NUM_HIGH && !slice_addr_is_low(end)) {
78 unsigned long start_index = GET_HIGH_SLICE_INDEX(start);
79 unsigned long align_end = ALIGN(end, (1UL << SLICE_HIGH_SHIFT));
80 unsigned long count = GET_HIGH_SLICE_INDEX(align_end) - start_index;
81
82 bitmap_set(ret->high_slices, start_index, count);
83 }
84 }
85
86 static int slice_area_is_free(struct mm_struct *mm, unsigned long addr,
87 unsigned long len)
88 {
89 struct vm_area_struct *vma;
90
91 if ((mm_ctx_slb_addr_limit(&mm->context) - len) < addr)
92 return 0;
93 vma = find_vma(mm, addr);
94 return (!vma || (addr + len) <= vm_start_gap(vma));
95 }
96
97 static int slice_low_has_vma(struct mm_struct *mm, unsigned long slice)
98 {
99 return !slice_area_is_free(mm, slice << SLICE_LOW_SHIFT,
100 1ul << SLICE_LOW_SHIFT);
101 }
102
103 static int slice_high_has_vma(struct mm_struct *mm, unsigned long slice)
104 {
105 unsigned long start = slice << SLICE_HIGH_SHIFT;
106 unsigned long end = start + (1ul << SLICE_HIGH_SHIFT);
107
108 /* Hack, so that each addresses is controlled by exactly one
109 * of the high or low area bitmaps, the first high area starts
110 * at 4GB, not 0 */
111 if (start == 0)
112 start = (unsigned long)SLICE_LOW_TOP;
113
114 return !slice_area_is_free(mm, start, end - start);
115 }
116
117 static void slice_mask_for_free(struct mm_struct *mm, struct slice_mask *ret,
118 unsigned long high_limit)
119 {
120 unsigned long i;
121
122 ret->low_slices = 0;
123 if (SLICE_NUM_HIGH)
124 bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
125
126 for (i = 0; i < SLICE_NUM_LOW; i++)
127 if (!slice_low_has_vma(mm, i))
128 ret->low_slices |= 1u << i;
129
130 if (slice_addr_is_low(high_limit - 1))
131 return;
132
133 for (i = 0; i < GET_HIGH_SLICE_INDEX(high_limit); i++)
134 if (!slice_high_has_vma(mm, i))
135 __set_bit(i, ret->high_slices);
136 }
137
138 static bool slice_check_range_fits(struct mm_struct *mm,
139 const struct slice_mask *available,
140 unsigned long start, unsigned long len)
141 {
142 unsigned long end = start + len - 1;
143 u64 low_slices = 0;
144
145 if (slice_addr_is_low(start)) {
146 unsigned long mend = min(end,
147 (unsigned long)(SLICE_LOW_TOP - 1));
148
149 low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
150 - (1u << GET_LOW_SLICE_INDEX(start));
151 }
152 if ((low_slices & available->low_slices) != low_slices)
153 return false;
154
155 if (SLICE_NUM_HIGH && !slice_addr_is_low(end)) {
156 unsigned long start_index = GET_HIGH_SLICE_INDEX(start);
157 unsigned long align_end = ALIGN(end, (1UL << SLICE_HIGH_SHIFT));
158 unsigned long count = GET_HIGH_SLICE_INDEX(align_end) - start_index;
159 unsigned long i;
160
161 for (i = start_index; i < start_index + count; i++) {
162 if (!test_bit(i, available->high_slices))
163 return false;
164 }
165 }
166
167 return true;
168 }
169
170 static void slice_flush_segments(void *parm)
171 {
172 #ifdef CONFIG_PPC64
173 struct mm_struct *mm = parm;
174 unsigned long flags;
175
176 if (mm != current->active_mm)
177 return;
178
179 copy_mm_to_paca(current->active_mm);
180
181 local_irq_save(flags);
182 slb_flush_and_restore_bolted();
183 local_irq_restore(flags);
184 #endif
185 }
186
187 static void slice_convert(struct mm_struct *mm,
188 const struct slice_mask *mask, int psize)
189 {
190 int index, mask_index;
191 /* Write the new slice psize bits */
192 unsigned char *hpsizes, *lpsizes;
193 struct slice_mask *psize_mask, *old_mask;
194 unsigned long i, flags;
195 int old_psize;
196
197 slice_dbg("slice_convert(mm=%p, psize=%d)\n", mm, psize);
198 slice_print_mask(" mask", mask);
199
200 psize_mask = slice_mask_for_size(&mm->context, psize);
201
202 /* We need to use a spinlock here to protect against
203 * concurrent 64k -> 4k demotion ...
204 */
205 spin_lock_irqsave(&slice_convert_lock, flags);
206
207 lpsizes = mm_ctx_low_slices(&mm->context);
208 for (i = 0; i < SLICE_NUM_LOW; i++) {
209 if (!(mask->low_slices & (1u << i)))
210 continue;
211
212 mask_index = i & 0x1;
213 index = i >> 1;
214
215 /* Update the slice_mask */
216 old_psize = (lpsizes[index] >> (mask_index * 4)) & 0xf;
217 old_mask = slice_mask_for_size(&mm->context, old_psize);
218 old_mask->low_slices &= ~(1u << i);
219 psize_mask->low_slices |= 1u << i;
220
221 /* Update the sizes array */
222 lpsizes[index] = (lpsizes[index] & ~(0xf << (mask_index * 4))) |
223 (((unsigned long)psize) << (mask_index * 4));
224 }
225
226 hpsizes = mm_ctx_high_slices(&mm->context);
227 for (i = 0; i < GET_HIGH_SLICE_INDEX(mm_ctx_slb_addr_limit(&mm->context)); i++) {
228 if (!test_bit(i, mask->high_slices))
229 continue;
230
231 mask_index = i & 0x1;
232 index = i >> 1;
233
234 /* Update the slice_mask */
235 old_psize = (hpsizes[index] >> (mask_index * 4)) & 0xf;
236 old_mask = slice_mask_for_size(&mm->context, old_psize);
237 __clear_bit(i, old_mask->high_slices);
238 __set_bit(i, psize_mask->high_slices);
239
240 /* Update the sizes array */
241 hpsizes[index] = (hpsizes[index] & ~(0xf << (mask_index * 4))) |
242 (((unsigned long)psize) << (mask_index * 4));
243 }
244
245 slice_dbg(" lsps=%lx, hsps=%lx\n",
246 (unsigned long)mm_ctx_low_slices(&mm->context),
247 (unsigned long)mm_ctx_high_slices(&mm->context));
248
249 spin_unlock_irqrestore(&slice_convert_lock, flags);
250
251 copro_flush_all_slbs(mm);
252 }
253
254 /*
255 * Compute which slice addr is part of;
256 * set *boundary_addr to the start or end boundary of that slice
257 * (depending on 'end' parameter);
258 * return boolean indicating if the slice is marked as available in the
259 * 'available' slice_mark.
260 */
261 static bool slice_scan_available(unsigned long addr,
262 const struct slice_mask *available,
263 int end, unsigned long *boundary_addr)
264 {
265 unsigned long slice;
266 if (slice_addr_is_low(addr)) {
267 slice = GET_LOW_SLICE_INDEX(addr);
268 *boundary_addr = (slice + end) << SLICE_LOW_SHIFT;
269 return !!(available->low_slices & (1u << slice));
270 } else {
271 slice = GET_HIGH_SLICE_INDEX(addr);
272 *boundary_addr = (slice + end) ?
273 ((slice + end) << SLICE_HIGH_SHIFT) : SLICE_LOW_TOP;
274 return !!test_bit(slice, available->high_slices);
275 }
276 }
277
278 static unsigned long slice_find_area_bottomup(struct mm_struct *mm,
279 unsigned long addr, unsigned long len,
280 const struct slice_mask *available,
281 int psize, unsigned long high_limit)
282 {
283 int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
284 unsigned long found, next_end;
285 struct vm_unmapped_area_info info = {
286 .length = len,
287 .align_mask = PAGE_MASK & ((1ul << pshift) - 1),
288 };
289 /*
290 * Check till the allow max value for this mmap request
291 */
292 while (addr < high_limit) {
293 info.low_limit = addr;
294 if (!slice_scan_available(addr, available, 1, &addr))
295 continue;
296
297 next_slice:
298 /*
299 * At this point [info.low_limit; addr) covers
300 * available slices only and ends at a slice boundary.
301 * Check if we need to reduce the range, or if we can
302 * extend it to cover the next available slice.
303 */
304 if (addr >= high_limit)
305 addr = high_limit;
306 else if (slice_scan_available(addr, available, 1, &next_end)) {
307 addr = next_end;
308 goto next_slice;
309 }
310 info.high_limit = addr;
311
312 found = vm_unmapped_area(&info);
313 if (!(found & ~PAGE_MASK))
314 return found;
315 }
316
317 return -ENOMEM;
318 }
319
320 static unsigned long slice_find_area_topdown(struct mm_struct *mm,
321 unsigned long addr, unsigned long len,
322 const struct slice_mask *available,
323 int psize, unsigned long high_limit)
324 {
325 int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
326 unsigned long found, prev;
327 struct vm_unmapped_area_info info = {
328 .flags = VM_UNMAPPED_AREA_TOPDOWN,
329 .length = len,
330 .align_mask = PAGE_MASK & ((1ul << pshift) - 1),
331 };
332 unsigned long min_addr = max(PAGE_SIZE, mmap_min_addr);
333
334 /*
335 * If we are trying to allocate above DEFAULT_MAP_WINDOW
336 * Add the different to the mmap_base.
337 * Only for that request for which high_limit is above
338 * DEFAULT_MAP_WINDOW we should apply this.
339 */
340 if (high_limit > DEFAULT_MAP_WINDOW)
341 addr += mm_ctx_slb_addr_limit(&mm->context) - DEFAULT_MAP_WINDOW;
342
343 while (addr > min_addr) {
344 info.high_limit = addr;
345 if (!slice_scan_available(addr - 1, available, 0, &addr))
346 continue;
347
348 prev_slice:
349 /*
350 * At this point [addr; info.high_limit) covers
351 * available slices only and starts at a slice boundary.
352 * Check if we need to reduce the range, or if we can
353 * extend it to cover the previous available slice.
354 */
355 if (addr < min_addr)
356 addr = min_addr;
357 else if (slice_scan_available(addr - 1, available, 0, &prev)) {
358 addr = prev;
359 goto prev_slice;
360 }
361 info.low_limit = addr;
362
363 found = vm_unmapped_area(&info);
364 if (!(found & ~PAGE_MASK))
365 return found;
366 }
367
368 /*
369 * A failed mmap() very likely causes application failure,
370 * so fall back to the bottom-up function here. This scenario
371 * can happen with large stack limits and large mmap()
372 * allocations.
373 */
374 return slice_find_area_bottomup(mm, TASK_UNMAPPED_BASE, len, available, psize, high_limit);
375 }
376
377
378 static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
379 const struct slice_mask *mask, int psize,
380 int topdown, unsigned long high_limit)
381 {
382 if (topdown)
383 return slice_find_area_topdown(mm, mm->mmap_base, len, mask, psize, high_limit);
384 else
385 return slice_find_area_bottomup(mm, mm->mmap_base, len, mask, psize, high_limit);
386 }
387
388 static inline void slice_copy_mask(struct slice_mask *dst,
389 const struct slice_mask *src)
390 {
391 dst->low_slices = src->low_slices;
392 if (!SLICE_NUM_HIGH)
393 return;
394 bitmap_copy(dst->high_slices, src->high_slices, SLICE_NUM_HIGH);
395 }
396
397 static inline void slice_or_mask(struct slice_mask *dst,
398 const struct slice_mask *src1,
399 const struct slice_mask *src2)
400 {
401 dst->low_slices = src1->low_slices | src2->low_slices;
402 if (!SLICE_NUM_HIGH)
403 return;
404 bitmap_or(dst->high_slices, src1->high_slices, src2->high_slices, SLICE_NUM_HIGH);
405 }
406
407 static inline void slice_andnot_mask(struct slice_mask *dst,
408 const struct slice_mask *src1,
409 const struct slice_mask *src2)
410 {
411 dst->low_slices = src1->low_slices & ~src2->low_slices;
412 if (!SLICE_NUM_HIGH)
413 return;
414 bitmap_andnot(dst->high_slices, src1->high_slices, src2->high_slices, SLICE_NUM_HIGH);
415 }
416
417 #ifdef CONFIG_PPC_64K_PAGES
418 #define MMU_PAGE_BASE MMU_PAGE_64K
419 #else
420 #define MMU_PAGE_BASE MMU_PAGE_4K
421 #endif
422
423 unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
424 unsigned long flags, unsigned int psize,
425 int topdown)
426 {
427 struct slice_mask good_mask;
428 struct slice_mask potential_mask;
429 const struct slice_mask *maskp;
430 const struct slice_mask *compat_maskp = NULL;
431 int fixed = (flags & MAP_FIXED);
432 int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
433 unsigned long page_size = 1UL << pshift;
434 struct mm_struct *mm = current->mm;
435 unsigned long newaddr;
436 unsigned long high_limit;
437
438 high_limit = DEFAULT_MAP_WINDOW;
439 if (addr >= high_limit || (fixed && (addr + len > high_limit)))
440 high_limit = TASK_SIZE;
441
442 if (len > high_limit)
443 return -ENOMEM;
444 if (len & (page_size - 1))
445 return -EINVAL;
446 if (fixed) {
447 if (addr & (page_size - 1))
448 return -EINVAL;
449 if (addr > high_limit - len)
450 return -ENOMEM;
451 }
452
453 if (high_limit > mm_ctx_slb_addr_limit(&mm->context)) {
454 /*
455 * Increasing the slb_addr_limit does not require
456 * slice mask cache to be recalculated because it should
457 * be already initialised beyond the old address limit.
458 */
459 mm_ctx_set_slb_addr_limit(&mm->context, high_limit);
460
461 on_each_cpu(slice_flush_segments, mm, 1);
462 }
463
464 /* Sanity checks */
465 BUG_ON(mm->task_size == 0);
466 BUG_ON(mm_ctx_slb_addr_limit(&mm->context) == 0);
467 VM_BUG_ON(radix_enabled());
468
469 slice_dbg("slice_get_unmapped_area(mm=%p, psize=%d...\n", mm, psize);
470 slice_dbg(" addr=%lx, len=%lx, flags=%lx, topdown=%d\n",
471 addr, len, flags, topdown);
472
473 /* If hint, make sure it matches our alignment restrictions */
474 if (!fixed && addr) {
475 addr = ALIGN(addr, page_size);
476 slice_dbg(" aligned addr=%lx\n", addr);
477 /* Ignore hint if it's too large or overlaps a VMA */
478 if (addr > high_limit - len || addr < mmap_min_addr ||
479 !slice_area_is_free(mm, addr, len))
480 addr = 0;
481 }
482
483 /* First make up a "good" mask of slices that have the right size
484 * already
485 */
486 maskp = slice_mask_for_size(&mm->context, psize);
487
488 /*
489 * Here "good" means slices that are already the right page size,
490 * "compat" means slices that have a compatible page size (i.e.
491 * 4k in a 64k pagesize kernel), and "free" means slices without
492 * any VMAs.
493 *
494 * If MAP_FIXED:
495 * check if fits in good | compat => OK
496 * check if fits in good | compat | free => convert free
497 * else bad
498 * If have hint:
499 * check if hint fits in good => OK
500 * check if hint fits in good | free => convert free
501 * Otherwise:
502 * search in good, found => OK
503 * search in good | free, found => convert free
504 * search in good | compat | free, found => convert free.
505 */
506
507 /*
508 * If we support combo pages, we can allow 64k pages in 4k slices
509 * The mask copies could be avoided in most cases here if we had
510 * a pointer to good mask for the next code to use.
511 */
512 if (IS_ENABLED(CONFIG_PPC_64K_PAGES) && psize == MMU_PAGE_64K) {
513 compat_maskp = slice_mask_for_size(&mm->context, MMU_PAGE_4K);
514 if (fixed)
515 slice_or_mask(&good_mask, maskp, compat_maskp);
516 else
517 slice_copy_mask(&good_mask, maskp);
518 } else {
519 slice_copy_mask(&good_mask, maskp);
520 }
521
522 slice_print_mask(" good_mask", &good_mask);
523 if (compat_maskp)
524 slice_print_mask(" compat_mask", compat_maskp);
525
526 /* First check hint if it's valid or if we have MAP_FIXED */
527 if (addr != 0 || fixed) {
528 /* Check if we fit in the good mask. If we do, we just return,
529 * nothing else to do
530 */
531 if (slice_check_range_fits(mm, &good_mask, addr, len)) {
532 slice_dbg(" fits good !\n");
533 newaddr = addr;
534 goto return_addr;
535 }
536 } else {
537 /* Now let's see if we can find something in the existing
538 * slices for that size
539 */
540 newaddr = slice_find_area(mm, len, &good_mask,
541 psize, topdown, high_limit);
542 if (newaddr != -ENOMEM) {
543 /* Found within the good mask, we don't have to setup,
544 * we thus return directly
545 */
546 slice_dbg(" found area at 0x%lx\n", newaddr);
547 goto return_addr;
548 }
549 }
550 /*
551 * We don't fit in the good mask, check what other slices are
552 * empty and thus can be converted
553 */
554 slice_mask_for_free(mm, &potential_mask, high_limit);
555 slice_or_mask(&potential_mask, &potential_mask, &good_mask);
556 slice_print_mask(" potential", &potential_mask);
557
558 if (addr != 0 || fixed) {
559 if (slice_check_range_fits(mm, &potential_mask, addr, len)) {
560 slice_dbg(" fits potential !\n");
561 newaddr = addr;
562 goto convert;
563 }
564 }
565
566 /* If we have MAP_FIXED and failed the above steps, then error out */
567 if (fixed)
568 return -EBUSY;
569
570 slice_dbg(" search...\n");
571
572 /* If we had a hint that didn't work out, see if we can fit
573 * anywhere in the good area.
574 */
575 if (addr) {
576 newaddr = slice_find_area(mm, len, &good_mask,
577 psize, topdown, high_limit);
578 if (newaddr != -ENOMEM) {
579 slice_dbg(" found area at 0x%lx\n", newaddr);
580 goto return_addr;
581 }
582 }
583
584 /* Now let's see if we can find something in the existing slices
585 * for that size plus free slices
586 */
587 newaddr = slice_find_area(mm, len, &potential_mask,
588 psize, topdown, high_limit);
589
590 if (IS_ENABLED(CONFIG_PPC_64K_PAGES) && newaddr == -ENOMEM &&
591 psize == MMU_PAGE_64K) {
592 /* retry the search with 4k-page slices included */
593 slice_or_mask(&potential_mask, &potential_mask, compat_maskp);
594 newaddr = slice_find_area(mm, len, &potential_mask,
595 psize, topdown, high_limit);
596 }
597
598 if (newaddr == -ENOMEM)
599 return -ENOMEM;
600
601 slice_range_to_mask(newaddr, len, &potential_mask);
602 slice_dbg(" found potential area at 0x%lx\n", newaddr);
603 slice_print_mask(" mask", &potential_mask);
604
605 convert:
606 /*
607 * Try to allocate the context before we do slice convert
608 * so that we handle the context allocation failure gracefully.
609 */
610 if (need_extra_context(mm, newaddr)) {
611 if (alloc_extended_context(mm, newaddr) < 0)
612 return -ENOMEM;
613 }
614
615 slice_andnot_mask(&potential_mask, &potential_mask, &good_mask);
616 if (compat_maskp && !fixed)
617 slice_andnot_mask(&potential_mask, &potential_mask, compat_maskp);
618 if (potential_mask.low_slices ||
619 (SLICE_NUM_HIGH &&
620 !bitmap_empty(potential_mask.high_slices, SLICE_NUM_HIGH))) {
621 slice_convert(mm, &potential_mask, psize);
622 if (psize > MMU_PAGE_BASE)
623 on_each_cpu(slice_flush_segments, mm, 1);
624 }
625 return newaddr;
626
627 return_addr:
628 if (need_extra_context(mm, newaddr)) {
629 if (alloc_extended_context(mm, newaddr) < 0)
630 return -ENOMEM;
631 }
632 return newaddr;
633 }
634 EXPORT_SYMBOL_GPL(slice_get_unmapped_area);
635
636 unsigned long arch_get_unmapped_area(struct file *filp,
637 unsigned long addr,
638 unsigned long len,
639 unsigned long pgoff,
640 unsigned long flags)
641 {
642 if (radix_enabled())
643 return generic_get_unmapped_area(filp, addr, len, pgoff, flags);
644
645 return slice_get_unmapped_area(addr, len, flags,
646 mm_ctx_user_psize(¤t->mm->context), 0);
647 }
648
649 unsigned long arch_get_unmapped_area_topdown(struct file *filp,
650 const unsigned long addr0,
651 const unsigned long len,
652 const unsigned long pgoff,
653 const unsigned long flags)
654 {
655 if (radix_enabled())
656 return generic_get_unmapped_area_topdown(filp, addr0, len, pgoff, flags);
657
658 return slice_get_unmapped_area(addr0, len, flags,
659 mm_ctx_user_psize(¤t->mm->context), 1);
660 }
661
662 unsigned int notrace get_slice_psize(struct mm_struct *mm, unsigned long addr)
663 {
664 unsigned char *psizes;
665 int index, mask_index;
666
667 VM_BUG_ON(radix_enabled());
668
669 if (slice_addr_is_low(addr)) {
670 psizes = mm_ctx_low_slices(&mm->context);
671 index = GET_LOW_SLICE_INDEX(addr);
672 } else {
673 psizes = mm_ctx_high_slices(&mm->context);
674 index = GET_HIGH_SLICE_INDEX(addr);
675 }
676 mask_index = index & 0x1;
677 return (psizes[index >> 1] >> (mask_index * 4)) & 0xf;
678 }
679 EXPORT_SYMBOL_GPL(get_slice_psize);
680
681 void slice_init_new_context_exec(struct mm_struct *mm)
682 {
683 unsigned char *hpsizes, *lpsizes;
684 struct slice_mask *mask;
685 unsigned int psize = mmu_virtual_psize;
686
687 slice_dbg("slice_init_new_context_exec(mm=%p)\n", mm);
688
689 /*
690 * In the case of exec, use the default limit. In the
691 * case of fork it is just inherited from the mm being
692 * duplicated.
693 */
694 mm_ctx_set_slb_addr_limit(&mm->context, SLB_ADDR_LIMIT_DEFAULT);
695 mm_ctx_set_user_psize(&mm->context, psize);
696
697 /*
698 * Set all slice psizes to the default.
699 */
700 lpsizes = mm_ctx_low_slices(&mm->context);
701 memset(lpsizes, (psize << 4) | psize, SLICE_NUM_LOW >> 1);
702
703 hpsizes = mm_ctx_high_slices(&mm->context);
704 memset(hpsizes, (psize << 4) | psize, SLICE_NUM_HIGH >> 1);
705
706 /*
707 * Slice mask cache starts zeroed, fill the default size cache.
708 */
709 mask = slice_mask_for_size(&mm->context, psize);
710 mask->low_slices = ~0UL;
711 if (SLICE_NUM_HIGH)
712 bitmap_fill(mask->high_slices, SLICE_NUM_HIGH);
713 }
714
715 void slice_setup_new_exec(void)
716 {
717 struct mm_struct *mm = current->mm;
718
719 slice_dbg("slice_setup_new_exec(mm=%p)\n", mm);
720
721 if (!is_32bit_task())
722 return;
723
724 mm_ctx_set_slb_addr_limit(&mm->context, DEFAULT_MAP_WINDOW);
725 }
726
727 void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
728 unsigned long len, unsigned int psize)
729 {
730 struct slice_mask mask;
731
732 VM_BUG_ON(radix_enabled());
733
734 slice_range_to_mask(start, len, &mask);
735 slice_convert(mm, &mask, psize);
736 }
737
738 #ifdef CONFIG_HUGETLB_PAGE
739 /*
740 * is_hugepage_only_range() is used by generic code to verify whether
741 * a normal mmap mapping (non hugetlbfs) is valid on a given area.
742 *
743 * until the generic code provides a more generic hook and/or starts
744 * calling arch get_unmapped_area for MAP_FIXED (which our implementation
745 * here knows how to deal with), we hijack it to keep standard mappings
746 * away from us.
747 *
748 * because of that generic code limitation, MAP_FIXED mapping cannot
749 * "convert" back a slice with no VMAs to the standard page size, only
750 * get_unmapped_area() can. It would be possible to fix it here but I
751 * prefer working on fixing the generic code instead.
752 *
753 * WARNING: This will not work if hugetlbfs isn't enabled since the
754 * generic code will redefine that function as 0 in that. This is ok
755 * for now as we only use slices with hugetlbfs enabled. This should
756 * be fixed as the generic code gets fixed.
757 */
758 int slice_is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
759 unsigned long len)
760 {
761 const struct slice_mask *maskp;
762 unsigned int psize = mm_ctx_user_psize(&mm->context);
763
764 VM_BUG_ON(radix_enabled());
765
766 maskp = slice_mask_for_size(&mm->context, psize);
767
768 /* We need to account for 4k slices too */
769 if (IS_ENABLED(CONFIG_PPC_64K_PAGES) && psize == MMU_PAGE_64K) {
770 const struct slice_mask *compat_maskp;
771 struct slice_mask available;
772
773 compat_maskp = slice_mask_for_size(&mm->context, MMU_PAGE_4K);
774 slice_or_mask(&available, maskp, compat_maskp);
775 return !slice_check_range_fits(mm, &available, addr, len);
776 }
777
778 return !slice_check_range_fits(mm, maskp, addr, len);
779 }
780
781 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
782 {
783 /* With radix we don't use slice, so derive it from vma*/
784 if (radix_enabled())
785 return vma_kernel_pagesize(vma);
786
787 return 1UL << mmu_psize_to_shift(get_slice_psize(vma->vm_mm, vma->vm_start));
788 }
789
790 static int file_to_psize(struct file *file)
791 {
792 struct hstate *hstate = hstate_file(file);
793 return shift_to_mmu_psize(huge_page_shift(hstate));
794 }
795
796 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
797 unsigned long len, unsigned long pgoff,
798 unsigned long flags)
799 {
800 if (radix_enabled())
801 return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags);
802
803 return slice_get_unmapped_area(addr, len, flags, file_to_psize(file), 1);
804 }
805 #endif
806
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.