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
slice_print_mask(const char * label,const struct slice_mask * mask)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
slice_print_mask(const char * label,const struct slice_mask * mask)48 static void slice_print_mask(const char *label, const struct slice_mask *mask) {}
49 #define slice_dbg(fmt...)
50
51 #endif
52
slice_addr_is_low(unsigned long addr)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
slice_range_to_mask(unsigned long start,unsigned long len,struct slice_mask * ret)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
slice_area_is_free(struct mm_struct * mm,unsigned long addr,unsigned long len)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
slice_low_has_vma(struct mm_struct * mm,unsigned long slice)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
slice_high_has_vma(struct mm_struct * mm,unsigned long slice)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
slice_mask_for_free(struct mm_struct * mm,struct slice_mask * ret,unsigned long high_limit)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
slice_check_range_fits(struct mm_struct * mm,const struct slice_mask * available,unsigned long start,unsigned long len)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
slice_flush_segments(void * parm)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
slice_convert(struct mm_struct * mm,const struct slice_mask * mask,int psize)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 */
slice_scan_available(unsigned long addr,const struct slice_mask * available,int end,unsigned long * boundary_addr)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
slice_find_area_bottomup(struct mm_struct * mm,unsigned long addr,unsigned long len,const struct slice_mask * available,int psize,unsigned long high_limit)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
287 info.flags = 0;
288 info.length = len;
289 info.align_mask = PAGE_MASK & ((1ul << pshift) - 1);
290 info.align_offset = 0;
291 /*
292 * Check till the allow max value for this mmap request
293 */
294 while (addr < high_limit) {
295 info.low_limit = addr;
296 if (!slice_scan_available(addr, available, 1, &addr))
297 continue;
298
299 next_slice:
300 /*
301 * At this point [info.low_limit; addr) covers
302 * available slices only and ends at a slice boundary.
303 * Check if we need to reduce the range, or if we can
304 * extend it to cover the next available slice.
305 */
306 if (addr >= high_limit)
307 addr = high_limit;
308 else if (slice_scan_available(addr, available, 1, &next_end)) {
309 addr = next_end;
310 goto next_slice;
311 }
312 info.high_limit = addr;
313
314 found = vm_unmapped_area(&info);
315 if (!(found & ~PAGE_MASK))
316 return found;
317 }
318
319 return -ENOMEM;
320 }
321
slice_find_area_topdown(struct mm_struct * mm,unsigned long addr,unsigned long len,const struct slice_mask * available,int psize,unsigned long high_limit)322 static unsigned long slice_find_area_topdown(struct mm_struct *mm,
323 unsigned long addr, unsigned long len,
324 const struct slice_mask *available,
325 int psize, unsigned long high_limit)
326 {
327 int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
328 unsigned long found, prev;
329 struct vm_unmapped_area_info info;
330 unsigned long min_addr = max(PAGE_SIZE, mmap_min_addr);
331
332 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
333 info.length = len;
334 info.align_mask = PAGE_MASK & ((1ul << pshift) - 1);
335 info.align_offset = 0;
336 /*
337 * If we are trying to allocate above DEFAULT_MAP_WINDOW
338 * Add the different to the mmap_base.
339 * Only for that request for which high_limit is above
340 * DEFAULT_MAP_WINDOW we should apply this.
341 */
342 if (high_limit > DEFAULT_MAP_WINDOW)
343 addr += mm_ctx_slb_addr_limit(&mm->context) - DEFAULT_MAP_WINDOW;
344
345 while (addr > min_addr) {
346 info.high_limit = addr;
347 if (!slice_scan_available(addr - 1, available, 0, &addr))
348 continue;
349
350 prev_slice:
351 /*
352 * At this point [addr; info.high_limit) covers
353 * available slices only and starts at a slice boundary.
354 * Check if we need to reduce the range, or if we can
355 * extend it to cover the previous available slice.
356 */
357 if (addr < min_addr)
358 addr = min_addr;
359 else if (slice_scan_available(addr - 1, available, 0, &prev)) {
360 addr = prev;
361 goto prev_slice;
362 }
363 info.low_limit = addr;
364
365 found = vm_unmapped_area(&info);
366 if (!(found & ~PAGE_MASK))
367 return found;
368 }
369
370 /*
371 * A failed mmap() very likely causes application failure,
372 * so fall back to the bottom-up function here. This scenario
373 * can happen with large stack limits and large mmap()
374 * allocations.
375 */
376 return slice_find_area_bottomup(mm, TASK_UNMAPPED_BASE, len, available, psize, high_limit);
377 }
378
379
slice_find_area(struct mm_struct * mm,unsigned long len,const struct slice_mask * mask,int psize,int topdown,unsigned long high_limit)380 static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
381 const struct slice_mask *mask, int psize,
382 int topdown, unsigned long high_limit)
383 {
384 if (topdown)
385 return slice_find_area_topdown(mm, mm->mmap_base, len, mask, psize, high_limit);
386 else
387 return slice_find_area_bottomup(mm, mm->mmap_base, len, mask, psize, high_limit);
388 }
389
slice_copy_mask(struct slice_mask * dst,const struct slice_mask * src)390 static inline void slice_copy_mask(struct slice_mask *dst,
391 const struct slice_mask *src)
392 {
393 dst->low_slices = src->low_slices;
394 if (!SLICE_NUM_HIGH)
395 return;
396 bitmap_copy(dst->high_slices, src->high_slices, SLICE_NUM_HIGH);
397 }
398
slice_or_mask(struct slice_mask * dst,const struct slice_mask * src1,const struct slice_mask * src2)399 static inline void slice_or_mask(struct slice_mask *dst,
400 const struct slice_mask *src1,
401 const struct slice_mask *src2)
402 {
403 dst->low_slices = src1->low_slices | src2->low_slices;
404 if (!SLICE_NUM_HIGH)
405 return;
406 bitmap_or(dst->high_slices, src1->high_slices, src2->high_slices, SLICE_NUM_HIGH);
407 }
408
slice_andnot_mask(struct slice_mask * dst,const struct slice_mask * src1,const struct slice_mask * src2)409 static inline void slice_andnot_mask(struct slice_mask *dst,
410 const struct slice_mask *src1,
411 const struct slice_mask *src2)
412 {
413 dst->low_slices = src1->low_slices & ~src2->low_slices;
414 if (!SLICE_NUM_HIGH)
415 return;
416 bitmap_andnot(dst->high_slices, src1->high_slices, src2->high_slices, SLICE_NUM_HIGH);
417 }
418
419 #ifdef CONFIG_PPC_64K_PAGES
420 #define MMU_PAGE_BASE MMU_PAGE_64K
421 #else
422 #define MMU_PAGE_BASE MMU_PAGE_4K
423 #endif
424
slice_get_unmapped_area(unsigned long addr,unsigned long len,unsigned long flags,unsigned int psize,int topdown)425 unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
426 unsigned long flags, unsigned int psize,
427 int topdown)
428 {
429 struct slice_mask good_mask;
430 struct slice_mask potential_mask;
431 const struct slice_mask *maskp;
432 const struct slice_mask *compat_maskp = NULL;
433 int fixed = (flags & MAP_FIXED);
434 int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
435 unsigned long page_size = 1UL << pshift;
436 struct mm_struct *mm = current->mm;
437 unsigned long newaddr;
438 unsigned long high_limit;
439
440 high_limit = DEFAULT_MAP_WINDOW;
441 if (addr >= high_limit || (fixed && (addr + len > high_limit)))
442 high_limit = TASK_SIZE;
443
444 if (len > high_limit)
445 return -ENOMEM;
446 if (len & (page_size - 1))
447 return -EINVAL;
448 if (fixed) {
449 if (addr & (page_size - 1))
450 return -EINVAL;
451 if (addr > high_limit - len)
452 return -ENOMEM;
453 }
454
455 if (high_limit > mm_ctx_slb_addr_limit(&mm->context)) {
456 /*
457 * Increasing the slb_addr_limit does not require
458 * slice mask cache to be recalculated because it should
459 * be already initialised beyond the old address limit.
460 */
461 mm_ctx_set_slb_addr_limit(&mm->context, high_limit);
462
463 on_each_cpu(slice_flush_segments, mm, 1);
464 }
465
466 /* Sanity checks */
467 BUG_ON(mm->task_size == 0);
468 BUG_ON(mm_ctx_slb_addr_limit(&mm->context) == 0);
469 VM_BUG_ON(radix_enabled());
470
471 slice_dbg("slice_get_unmapped_area(mm=%p, psize=%d...\n", mm, psize);
472 slice_dbg(" addr=%lx, len=%lx, flags=%lx, topdown=%d\n",
473 addr, len, flags, topdown);
474
475 /* If hint, make sure it matches our alignment restrictions */
476 if (!fixed && addr) {
477 addr = ALIGN(addr, page_size);
478 slice_dbg(" aligned addr=%lx\n", addr);
479 /* Ignore hint if it's too large or overlaps a VMA */
480 if (addr > high_limit - len || addr < mmap_min_addr ||
481 !slice_area_is_free(mm, addr, len))
482 addr = 0;
483 }
484
485 /* First make up a "good" mask of slices that have the right size
486 * already
487 */
488 maskp = slice_mask_for_size(&mm->context, psize);
489
490 /*
491 * Here "good" means slices that are already the right page size,
492 * "compat" means slices that have a compatible page size (i.e.
493 * 4k in a 64k pagesize kernel), and "free" means slices without
494 * any VMAs.
495 *
496 * If MAP_FIXED:
497 * check if fits in good | compat => OK
498 * check if fits in good | compat | free => convert free
499 * else bad
500 * If have hint:
501 * check if hint fits in good => OK
502 * check if hint fits in good | free => convert free
503 * Otherwise:
504 * search in good, found => OK
505 * search in good | free, found => convert free
506 * search in good | compat | free, found => convert free.
507 */
508
509 /*
510 * If we support combo pages, we can allow 64k pages in 4k slices
511 * The mask copies could be avoided in most cases here if we had
512 * a pointer to good mask for the next code to use.
513 */
514 if (IS_ENABLED(CONFIG_PPC_64K_PAGES) && psize == MMU_PAGE_64K) {
515 compat_maskp = slice_mask_for_size(&mm->context, MMU_PAGE_4K);
516 if (fixed)
517 slice_or_mask(&good_mask, maskp, compat_maskp);
518 else
519 slice_copy_mask(&good_mask, maskp);
520 } else {
521 slice_copy_mask(&good_mask, maskp);
522 }
523
524 slice_print_mask(" good_mask", &good_mask);
525 if (compat_maskp)
526 slice_print_mask(" compat_mask", compat_maskp);
527
528 /* First check hint if it's valid or if we have MAP_FIXED */
529 if (addr != 0 || fixed) {
530 /* Check if we fit in the good mask. If we do, we just return,
531 * nothing else to do
532 */
533 if (slice_check_range_fits(mm, &good_mask, addr, len)) {
534 slice_dbg(" fits good !\n");
535 newaddr = addr;
536 goto return_addr;
537 }
538 } else {
539 /* Now let's see if we can find something in the existing
540 * slices for that size
541 */
542 newaddr = slice_find_area(mm, len, &good_mask,
543 psize, topdown, high_limit);
544 if (newaddr != -ENOMEM) {
545 /* Found within the good mask, we don't have to setup,
546 * we thus return directly
547 */
548 slice_dbg(" found area at 0x%lx\n", newaddr);
549 goto return_addr;
550 }
551 }
552 /*
553 * We don't fit in the good mask, check what other slices are
554 * empty and thus can be converted
555 */
556 slice_mask_for_free(mm, &potential_mask, high_limit);
557 slice_or_mask(&potential_mask, &potential_mask, &good_mask);
558 slice_print_mask(" potential", &potential_mask);
559
560 if (addr != 0 || fixed) {
561 if (slice_check_range_fits(mm, &potential_mask, addr, len)) {
562 slice_dbg(" fits potential !\n");
563 newaddr = addr;
564 goto convert;
565 }
566 }
567
568 /* If we have MAP_FIXED and failed the above steps, then error out */
569 if (fixed)
570 return -EBUSY;
571
572 slice_dbg(" search...\n");
573
574 /* If we had a hint that didn't work out, see if we can fit
575 * anywhere in the good area.
576 */
577 if (addr) {
578 newaddr = slice_find_area(mm, len, &good_mask,
579 psize, topdown, high_limit);
580 if (newaddr != -ENOMEM) {
581 slice_dbg(" found area at 0x%lx\n", newaddr);
582 goto return_addr;
583 }
584 }
585
586 /* Now let's see if we can find something in the existing slices
587 * for that size plus free slices
588 */
589 newaddr = slice_find_area(mm, len, &potential_mask,
590 psize, topdown, high_limit);
591
592 if (IS_ENABLED(CONFIG_PPC_64K_PAGES) && newaddr == -ENOMEM &&
593 psize == MMU_PAGE_64K) {
594 /* retry the search with 4k-page slices included */
595 slice_or_mask(&potential_mask, &potential_mask, compat_maskp);
596 newaddr = slice_find_area(mm, len, &potential_mask,
597 psize, topdown, high_limit);
598 }
599
600 if (newaddr == -ENOMEM)
601 return -ENOMEM;
602
603 slice_range_to_mask(newaddr, len, &potential_mask);
604 slice_dbg(" found potential area at 0x%lx\n", newaddr);
605 slice_print_mask(" mask", &potential_mask);
606
607 convert:
608 /*
609 * Try to allocate the context before we do slice convert
610 * so that we handle the context allocation failure gracefully.
611 */
612 if (need_extra_context(mm, newaddr)) {
613 if (alloc_extended_context(mm, newaddr) < 0)
614 return -ENOMEM;
615 }
616
617 slice_andnot_mask(&potential_mask, &potential_mask, &good_mask);
618 if (compat_maskp && !fixed)
619 slice_andnot_mask(&potential_mask, &potential_mask, compat_maskp);
620 if (potential_mask.low_slices ||
621 (SLICE_NUM_HIGH &&
622 !bitmap_empty(potential_mask.high_slices, SLICE_NUM_HIGH))) {
623 slice_convert(mm, &potential_mask, psize);
624 if (psize > MMU_PAGE_BASE)
625 on_each_cpu(slice_flush_segments, mm, 1);
626 }
627 return newaddr;
628
629 return_addr:
630 if (need_extra_context(mm, newaddr)) {
631 if (alloc_extended_context(mm, newaddr) < 0)
632 return -ENOMEM;
633 }
634 return newaddr;
635 }
636 EXPORT_SYMBOL_GPL(slice_get_unmapped_area);
637
arch_get_unmapped_area(struct file * filp,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)638 unsigned long arch_get_unmapped_area(struct file *filp,
639 unsigned long addr,
640 unsigned long len,
641 unsigned long pgoff,
642 unsigned long flags)
643 {
644 if (radix_enabled())
645 return generic_get_unmapped_area(filp, addr, len, pgoff, flags);
646
647 return slice_get_unmapped_area(addr, len, flags,
648 mm_ctx_user_psize(¤t->mm->context), 0);
649 }
650
arch_get_unmapped_area_topdown(struct file * filp,const unsigned long addr0,const unsigned long len,const unsigned long pgoff,const unsigned long flags)651 unsigned long arch_get_unmapped_area_topdown(struct file *filp,
652 const unsigned long addr0,
653 const unsigned long len,
654 const unsigned long pgoff,
655 const unsigned long flags)
656 {
657 if (radix_enabled())
658 return generic_get_unmapped_area_topdown(filp, addr0, len, pgoff, flags);
659
660 return slice_get_unmapped_area(addr0, len, flags,
661 mm_ctx_user_psize(¤t->mm->context), 1);
662 }
663
get_slice_psize(struct mm_struct * mm,unsigned long addr)664 unsigned int notrace get_slice_psize(struct mm_struct *mm, unsigned long addr)
665 {
666 unsigned char *psizes;
667 int index, mask_index;
668
669 VM_BUG_ON(radix_enabled());
670
671 if (slice_addr_is_low(addr)) {
672 psizes = mm_ctx_low_slices(&mm->context);
673 index = GET_LOW_SLICE_INDEX(addr);
674 } else {
675 psizes = mm_ctx_high_slices(&mm->context);
676 index = GET_HIGH_SLICE_INDEX(addr);
677 }
678 mask_index = index & 0x1;
679 return (psizes[index >> 1] >> (mask_index * 4)) & 0xf;
680 }
681 EXPORT_SYMBOL_GPL(get_slice_psize);
682
slice_init_new_context_exec(struct mm_struct * mm)683 void slice_init_new_context_exec(struct mm_struct *mm)
684 {
685 unsigned char *hpsizes, *lpsizes;
686 struct slice_mask *mask;
687 unsigned int psize = mmu_virtual_psize;
688
689 slice_dbg("slice_init_new_context_exec(mm=%p)\n", mm);
690
691 /*
692 * In the case of exec, use the default limit. In the
693 * case of fork it is just inherited from the mm being
694 * duplicated.
695 */
696 mm_ctx_set_slb_addr_limit(&mm->context, SLB_ADDR_LIMIT_DEFAULT);
697 mm_ctx_set_user_psize(&mm->context, psize);
698
699 /*
700 * Set all slice psizes to the default.
701 */
702 lpsizes = mm_ctx_low_slices(&mm->context);
703 memset(lpsizes, (psize << 4) | psize, SLICE_NUM_LOW >> 1);
704
705 hpsizes = mm_ctx_high_slices(&mm->context);
706 memset(hpsizes, (psize << 4) | psize, SLICE_NUM_HIGH >> 1);
707
708 /*
709 * Slice mask cache starts zeroed, fill the default size cache.
710 */
711 mask = slice_mask_for_size(&mm->context, psize);
712 mask->low_slices = ~0UL;
713 if (SLICE_NUM_HIGH)
714 bitmap_fill(mask->high_slices, SLICE_NUM_HIGH);
715 }
716
slice_setup_new_exec(void)717 void slice_setup_new_exec(void)
718 {
719 struct mm_struct *mm = current->mm;
720
721 slice_dbg("slice_setup_new_exec(mm=%p)\n", mm);
722
723 if (!is_32bit_task())
724 return;
725
726 mm_ctx_set_slb_addr_limit(&mm->context, DEFAULT_MAP_WINDOW);
727 }
728
slice_set_range_psize(struct mm_struct * mm,unsigned long start,unsigned long len,unsigned int psize)729 void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
730 unsigned long len, unsigned int psize)
731 {
732 struct slice_mask mask;
733
734 VM_BUG_ON(radix_enabled());
735
736 slice_range_to_mask(start, len, &mask);
737 slice_convert(mm, &mask, psize);
738 }
739
740 #ifdef CONFIG_HUGETLB_PAGE
741 /*
742 * is_hugepage_only_range() is used by generic code to verify whether
743 * a normal mmap mapping (non hugetlbfs) is valid on a given area.
744 *
745 * until the generic code provides a more generic hook and/or starts
746 * calling arch get_unmapped_area for MAP_FIXED (which our implementation
747 * here knows how to deal with), we hijack it to keep standard mappings
748 * away from us.
749 *
750 * because of that generic code limitation, MAP_FIXED mapping cannot
751 * "convert" back a slice with no VMAs to the standard page size, only
752 * get_unmapped_area() can. It would be possible to fix it here but I
753 * prefer working on fixing the generic code instead.
754 *
755 * WARNING: This will not work if hugetlbfs isn't enabled since the
756 * generic code will redefine that function as 0 in that. This is ok
757 * for now as we only use slices with hugetlbfs enabled. This should
758 * be fixed as the generic code gets fixed.
759 */
slice_is_hugepage_only_range(struct mm_struct * mm,unsigned long addr,unsigned long len)760 int slice_is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
761 unsigned long len)
762 {
763 const struct slice_mask *maskp;
764 unsigned int psize = mm_ctx_user_psize(&mm->context);
765
766 VM_BUG_ON(radix_enabled());
767
768 maskp = slice_mask_for_size(&mm->context, psize);
769
770 /* We need to account for 4k slices too */
771 if (IS_ENABLED(CONFIG_PPC_64K_PAGES) && psize == MMU_PAGE_64K) {
772 const struct slice_mask *compat_maskp;
773 struct slice_mask available;
774
775 compat_maskp = slice_mask_for_size(&mm->context, MMU_PAGE_4K);
776 slice_or_mask(&available, maskp, compat_maskp);
777 return !slice_check_range_fits(mm, &available, addr, len);
778 }
779
780 return !slice_check_range_fits(mm, maskp, addr, len);
781 }
782
vma_mmu_pagesize(struct vm_area_struct * vma)783 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
784 {
785 /* With radix we don't use slice, so derive it from vma*/
786 if (radix_enabled())
787 return vma_kernel_pagesize(vma);
788
789 return 1UL << mmu_psize_to_shift(get_slice_psize(vma->vm_mm, vma->vm_start));
790 }
791
file_to_psize(struct file * file)792 static int file_to_psize(struct file *file)
793 {
794 struct hstate *hstate = hstate_file(file);
795 return shift_to_mmu_psize(huge_page_shift(hstate));
796 }
797
hugetlb_get_unmapped_area(struct file * file,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)798 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
799 unsigned long len, unsigned long pgoff,
800 unsigned long flags)
801 {
802 if (radix_enabled())
803 return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags);
804
805 return slice_get_unmapped_area(addr, len, flags, file_to_psize(file), 1);
806 }
807 #endif
808