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Linux/arch/powerpc/mm/hugetlbpage.c

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  1 /*
  2  * PPC Huge TLB Page Support for Kernel.
  3  *
  4  * Copyright (C) 2003 David Gibson, IBM Corporation.
  5  * Copyright (C) 2011 Becky Bruce, Freescale Semiconductor
  6  *
  7  * Based on the IA-32 version:
  8  * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
  9  */
 10 
 11 #include <linux/mm.h>
 12 #include <linux/io.h>
 13 #include <linux/slab.h>
 14 #include <linux/hugetlb.h>
 15 #include <linux/export.h>
 16 #include <linux/of_fdt.h>
 17 #include <linux/memblock.h>
 18 #include <linux/bootmem.h>
 19 #include <linux/moduleparam.h>
 20 #include <asm/pgtable.h>
 21 #include <asm/pgalloc.h>
 22 #include <asm/tlb.h>
 23 #include <asm/setup.h>
 24 #include <asm/hugetlb.h>
 25 
 26 #ifdef CONFIG_HUGETLB_PAGE
 27 
 28 #define PAGE_SHIFT_64K  16
 29 #define PAGE_SHIFT_16M  24
 30 #define PAGE_SHIFT_16G  34
 31 
 32 unsigned int HPAGE_SHIFT;
 33 
 34 /*
 35  * Tracks gpages after the device tree is scanned and before the
 36  * huge_boot_pages list is ready.  On non-Freescale implementations, this is
 37  * just used to track 16G pages and so is a single array.  FSL-based
 38  * implementations may have more than one gpage size, so we need multiple
 39  * arrays
 40  */
 41 #ifdef CONFIG_PPC_FSL_BOOK3E
 42 #define MAX_NUMBER_GPAGES       128
 43 struct psize_gpages {
 44         u64 gpage_list[MAX_NUMBER_GPAGES];
 45         unsigned int nr_gpages;
 46 };
 47 static struct psize_gpages gpage_freearray[MMU_PAGE_COUNT];
 48 #else
 49 #define MAX_NUMBER_GPAGES       1024
 50 static u64 gpage_freearray[MAX_NUMBER_GPAGES];
 51 static unsigned nr_gpages;
 52 #endif
 53 
 54 #define hugepd_none(hpd)        ((hpd).pd == 0)
 55 
 56 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 57 {
 58         /* Only called for hugetlbfs pages, hence can ignore THP */
 59         return __find_linux_pte_or_hugepte(mm->pgd, addr, NULL, NULL);
 60 }
 61 
 62 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
 63                            unsigned long address, unsigned pdshift, unsigned pshift)
 64 {
 65         struct kmem_cache *cachep;
 66         pte_t *new;
 67 
 68 #ifdef CONFIG_PPC_FSL_BOOK3E
 69         int i;
 70         int num_hugepd = 1 << (pshift - pdshift);
 71         cachep = hugepte_cache;
 72 #else
 73         cachep = PGT_CACHE(pdshift - pshift);
 74 #endif
 75 
 76         new = kmem_cache_zalloc(cachep, GFP_KERNEL);
 77 
 78         BUG_ON(pshift > HUGEPD_SHIFT_MASK);
 79         BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);
 80 
 81         if (! new)
 82                 return -ENOMEM;
 83 
 84         /*
 85          * Make sure other cpus find the hugepd set only after a
 86          * properly initialized page table is visible to them.
 87          * For more details look for comment in __pte_alloc().
 88          */
 89         smp_wmb();
 90 
 91         spin_lock(&mm->page_table_lock);
 92 #ifdef CONFIG_PPC_FSL_BOOK3E
 93         /*
 94          * We have multiple higher-level entries that point to the same
 95          * actual pte location.  Fill in each as we go and backtrack on error.
 96          * We need all of these so the DTLB pgtable walk code can find the
 97          * right higher-level entry without knowing if it's a hugepage or not.
 98          */
 99         for (i = 0; i < num_hugepd; i++, hpdp++) {
100                 if (unlikely(!hugepd_none(*hpdp)))
101                         break;
102                 else
103                         /* We use the old format for PPC_FSL_BOOK3E */
104                         hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift;
105         }
106         /* If we bailed from the for loop early, an error occurred, clean up */
107         if (i < num_hugepd) {
108                 for (i = i - 1 ; i >= 0; i--, hpdp--)
109                         hpdp->pd = 0;
110                 kmem_cache_free(cachep, new);
111         }
112 #else
113         if (!hugepd_none(*hpdp))
114                 kmem_cache_free(cachep, new);
115         else {
116 #ifdef CONFIG_PPC_BOOK3S_64
117                 hpdp->pd = __pa(new) | (shift_to_mmu_psize(pshift) << 2);
118 #else
119                 hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift;
120 #endif
121         }
122 #endif
123         spin_unlock(&mm->page_table_lock);
124         return 0;
125 }
126 
127 /*
128  * These macros define how to determine which level of the page table holds
129  * the hpdp.
130  */
131 #ifdef CONFIG_PPC_FSL_BOOK3E
132 #define HUGEPD_PGD_SHIFT PGDIR_SHIFT
133 #define HUGEPD_PUD_SHIFT PUD_SHIFT
134 #else
135 #define HUGEPD_PGD_SHIFT PUD_SHIFT
136 #define HUGEPD_PUD_SHIFT PMD_SHIFT
137 #endif
138 
139 #ifdef CONFIG_PPC_BOOK3S_64
140 /*
141  * At this point we do the placement change only for BOOK3S 64. This would
142  * possibly work on other subarchs.
143  */
144 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
145 {
146         pgd_t *pg;
147         pud_t *pu;
148         pmd_t *pm;
149         hugepd_t *hpdp = NULL;
150         unsigned pshift = __ffs(sz);
151         unsigned pdshift = PGDIR_SHIFT;
152 
153         addr &= ~(sz-1);
154         pg = pgd_offset(mm, addr);
155 
156         if (pshift == PGDIR_SHIFT)
157                 /* 16GB huge page */
158                 return (pte_t *) pg;
159         else if (pshift > PUD_SHIFT)
160                 /*
161                  * We need to use hugepd table
162                  */
163                 hpdp = (hugepd_t *)pg;
164         else {
165                 pdshift = PUD_SHIFT;
166                 pu = pud_alloc(mm, pg, addr);
167                 if (pshift == PUD_SHIFT)
168                         return (pte_t *)pu;
169                 else if (pshift > PMD_SHIFT)
170                         hpdp = (hugepd_t *)pu;
171                 else {
172                         pdshift = PMD_SHIFT;
173                         pm = pmd_alloc(mm, pu, addr);
174                         if (pshift == PMD_SHIFT)
175                                 /* 16MB hugepage */
176                                 return (pte_t *)pm;
177                         else
178                                 hpdp = (hugepd_t *)pm;
179                 }
180         }
181         if (!hpdp)
182                 return NULL;
183 
184         BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
185 
186         if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift))
187                 return NULL;
188 
189         return hugepte_offset(*hpdp, addr, pdshift);
190 }
191 
192 #else
193 
194 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
195 {
196         pgd_t *pg;
197         pud_t *pu;
198         pmd_t *pm;
199         hugepd_t *hpdp = NULL;
200         unsigned pshift = __ffs(sz);
201         unsigned pdshift = PGDIR_SHIFT;
202 
203         addr &= ~(sz-1);
204 
205         pg = pgd_offset(mm, addr);
206 
207         if (pshift >= HUGEPD_PGD_SHIFT) {
208                 hpdp = (hugepd_t *)pg;
209         } else {
210                 pdshift = PUD_SHIFT;
211                 pu = pud_alloc(mm, pg, addr);
212                 if (pshift >= HUGEPD_PUD_SHIFT) {
213                         hpdp = (hugepd_t *)pu;
214                 } else {
215                         pdshift = PMD_SHIFT;
216                         pm = pmd_alloc(mm, pu, addr);
217                         hpdp = (hugepd_t *)pm;
218                 }
219         }
220 
221         if (!hpdp)
222                 return NULL;
223 
224         BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
225 
226         if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift))
227                 return NULL;
228 
229         return hugepte_offset(*hpdp, addr, pdshift);
230 }
231 #endif
232 
233 #ifdef CONFIG_PPC_FSL_BOOK3E
234 /* Build list of addresses of gigantic pages.  This function is used in early
235  * boot before the buddy allocator is setup.
236  */
237 void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
238 {
239         unsigned int idx = shift_to_mmu_psize(__ffs(page_size));
240         int i;
241 
242         if (addr == 0)
243                 return;
244 
245         gpage_freearray[idx].nr_gpages = number_of_pages;
246 
247         for (i = 0; i < number_of_pages; i++) {
248                 gpage_freearray[idx].gpage_list[i] = addr;
249                 addr += page_size;
250         }
251 }
252 
253 /*
254  * Moves the gigantic page addresses from the temporary list to the
255  * huge_boot_pages list.
256  */
257 int alloc_bootmem_huge_page(struct hstate *hstate)
258 {
259         struct huge_bootmem_page *m;
260         int idx = shift_to_mmu_psize(huge_page_shift(hstate));
261         int nr_gpages = gpage_freearray[idx].nr_gpages;
262 
263         if (nr_gpages == 0)
264                 return 0;
265 
266 #ifdef CONFIG_HIGHMEM
267         /*
268          * If gpages can be in highmem we can't use the trick of storing the
269          * data structure in the page; allocate space for this
270          */
271         m = memblock_virt_alloc(sizeof(struct huge_bootmem_page), 0);
272         m->phys = gpage_freearray[idx].gpage_list[--nr_gpages];
273 #else
274         m = phys_to_virt(gpage_freearray[idx].gpage_list[--nr_gpages]);
275 #endif
276 
277         list_add(&m->list, &huge_boot_pages);
278         gpage_freearray[idx].nr_gpages = nr_gpages;
279         gpage_freearray[idx].gpage_list[nr_gpages] = 0;
280         m->hstate = hstate;
281 
282         return 1;
283 }
284 /*
285  * Scan the command line hugepagesz= options for gigantic pages; store those in
286  * a list that we use to allocate the memory once all options are parsed.
287  */
288 
289 unsigned long gpage_npages[MMU_PAGE_COUNT];
290 
291 static int __init do_gpage_early_setup(char *param, char *val,
292                                        const char *unused, void *arg)
293 {
294         static phys_addr_t size;
295         unsigned long npages;
296 
297         /*
298          * The hugepagesz and hugepages cmdline options are interleaved.  We
299          * use the size variable to keep track of whether or not this was done
300          * properly and skip over instances where it is incorrect.  Other
301          * command-line parsing code will issue warnings, so we don't need to.
302          *
303          */
304         if ((strcmp(param, "default_hugepagesz") == 0) ||
305             (strcmp(param, "hugepagesz") == 0)) {
306                 size = memparse(val, NULL);
307         } else if (strcmp(param, "hugepages") == 0) {
308                 if (size != 0) {
309                         if (sscanf(val, "%lu", &npages) <= 0)
310                                 npages = 0;
311                         if (npages > MAX_NUMBER_GPAGES) {
312                                 pr_warn("MMU: %lu pages requested for page "
313                                         "size %llu KB, limiting to "
314                                         __stringify(MAX_NUMBER_GPAGES) "\n",
315                                         npages, size / 1024);
316                                 npages = MAX_NUMBER_GPAGES;
317                         }
318                         gpage_npages[shift_to_mmu_psize(__ffs(size))] = npages;
319                         size = 0;
320                 }
321         }
322         return 0;
323 }
324 
325 
326 /*
327  * This function allocates physical space for pages that are larger than the
328  * buddy allocator can handle.  We want to allocate these in highmem because
329  * the amount of lowmem is limited.  This means that this function MUST be
330  * called before lowmem_end_addr is set up in MMU_init() in order for the lmb
331  * allocate to grab highmem.
332  */
333 void __init reserve_hugetlb_gpages(void)
334 {
335         static __initdata char cmdline[COMMAND_LINE_SIZE];
336         phys_addr_t size, base;
337         int i;
338 
339         strlcpy(cmdline, boot_command_line, COMMAND_LINE_SIZE);
340         parse_args("hugetlb gpages", cmdline, NULL, 0, 0, 0,
341                         NULL, &do_gpage_early_setup);
342 
343         /*
344          * Walk gpage list in reverse, allocating larger page sizes first.
345          * Skip over unsupported sizes, or sizes that have 0 gpages allocated.
346          * When we reach the point in the list where pages are no longer
347          * considered gpages, we're done.
348          */
349         for (i = MMU_PAGE_COUNT-1; i >= 0; i--) {
350                 if (mmu_psize_defs[i].shift == 0 || gpage_npages[i] == 0)
351                         continue;
352                 else if (mmu_psize_to_shift(i) < (MAX_ORDER + PAGE_SHIFT))
353                         break;
354 
355                 size = (phys_addr_t)(1ULL << mmu_psize_to_shift(i));
356                 base = memblock_alloc_base(size * gpage_npages[i], size,
357                                            MEMBLOCK_ALLOC_ANYWHERE);
358                 add_gpage(base, size, gpage_npages[i]);
359         }
360 }
361 
362 #else /* !PPC_FSL_BOOK3E */
363 
364 /* Build list of addresses of gigantic pages.  This function is used in early
365  * boot before the buddy allocator is setup.
366  */
367 void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
368 {
369         if (!addr)
370                 return;
371         while (number_of_pages > 0) {
372                 gpage_freearray[nr_gpages] = addr;
373                 nr_gpages++;
374                 number_of_pages--;
375                 addr += page_size;
376         }
377 }
378 
379 /* Moves the gigantic page addresses from the temporary list to the
380  * huge_boot_pages list.
381  */
382 int alloc_bootmem_huge_page(struct hstate *hstate)
383 {
384         struct huge_bootmem_page *m;
385         if (nr_gpages == 0)
386                 return 0;
387         m = phys_to_virt(gpage_freearray[--nr_gpages]);
388         gpage_freearray[nr_gpages] = 0;
389         list_add(&m->list, &huge_boot_pages);
390         m->hstate = hstate;
391         return 1;
392 }
393 #endif
394 
395 #ifdef CONFIG_PPC_FSL_BOOK3E
396 #define HUGEPD_FREELIST_SIZE \
397         ((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))
398 
399 struct hugepd_freelist {
400         struct rcu_head rcu;
401         unsigned int index;
402         void *ptes[0];
403 };
404 
405 static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur);
406 
407 static void hugepd_free_rcu_callback(struct rcu_head *head)
408 {
409         struct hugepd_freelist *batch =
410                 container_of(head, struct hugepd_freelist, rcu);
411         unsigned int i;
412 
413         for (i = 0; i < batch->index; i++)
414                 kmem_cache_free(hugepte_cache, batch->ptes[i]);
415 
416         free_page((unsigned long)batch);
417 }
418 
419 static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
420 {
421         struct hugepd_freelist **batchp;
422 
423         batchp = &get_cpu_var(hugepd_freelist_cur);
424 
425         if (atomic_read(&tlb->mm->mm_users) < 2 ||
426             cpumask_equal(mm_cpumask(tlb->mm),
427                           cpumask_of(smp_processor_id()))) {
428                 kmem_cache_free(hugepte_cache, hugepte);
429                 put_cpu_var(hugepd_freelist_cur);
430                 return;
431         }
432 
433         if (*batchp == NULL) {
434                 *batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC);
435                 (*batchp)->index = 0;
436         }
437 
438         (*batchp)->ptes[(*batchp)->index++] = hugepte;
439         if ((*batchp)->index == HUGEPD_FREELIST_SIZE) {
440                 call_rcu_sched(&(*batchp)->rcu, hugepd_free_rcu_callback);
441                 *batchp = NULL;
442         }
443         put_cpu_var(hugepd_freelist_cur);
444 }
445 #endif
446 
447 static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift,
448                               unsigned long start, unsigned long end,
449                               unsigned long floor, unsigned long ceiling)
450 {
451         pte_t *hugepte = hugepd_page(*hpdp);
452         int i;
453 
454         unsigned long pdmask = ~((1UL << pdshift) - 1);
455         unsigned int num_hugepd = 1;
456 
457 #ifdef CONFIG_PPC_FSL_BOOK3E
458         /* Note: On fsl the hpdp may be the first of several */
459         num_hugepd = (1 << (hugepd_shift(*hpdp) - pdshift));
460 #else
461         unsigned int shift = hugepd_shift(*hpdp);
462 #endif
463 
464         start &= pdmask;
465         if (start < floor)
466                 return;
467         if (ceiling) {
468                 ceiling &= pdmask;
469                 if (! ceiling)
470                         return;
471         }
472         if (end - 1 > ceiling - 1)
473                 return;
474 
475         for (i = 0; i < num_hugepd; i++, hpdp++)
476                 hpdp->pd = 0;
477 
478 #ifdef CONFIG_PPC_FSL_BOOK3E
479         hugepd_free(tlb, hugepte);
480 #else
481         pgtable_free_tlb(tlb, hugepte, pdshift - shift);
482 #endif
483 }
484 
485 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
486                                    unsigned long addr, unsigned long end,
487                                    unsigned long floor, unsigned long ceiling)
488 {
489         pmd_t *pmd;
490         unsigned long next;
491         unsigned long start;
492 
493         start = addr;
494         do {
495                 pmd = pmd_offset(pud, addr);
496                 next = pmd_addr_end(addr, end);
497                 if (!is_hugepd(__hugepd(pmd_val(*pmd)))) {
498                         /*
499                          * if it is not hugepd pointer, we should already find
500                          * it cleared.
501                          */
502                         WARN_ON(!pmd_none_or_clear_bad(pmd));
503                         continue;
504                 }
505 #ifdef CONFIG_PPC_FSL_BOOK3E
506                 /*
507                  * Increment next by the size of the huge mapping since
508                  * there may be more than one entry at this level for a
509                  * single hugepage, but all of them point to
510                  * the same kmem cache that holds the hugepte.
511                  */
512                 next = addr + (1 << hugepd_shift(*(hugepd_t *)pmd));
513 #endif
514                 free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
515                                   addr, next, floor, ceiling);
516         } while (addr = next, addr != end);
517 
518         start &= PUD_MASK;
519         if (start < floor)
520                 return;
521         if (ceiling) {
522                 ceiling &= PUD_MASK;
523                 if (!ceiling)
524                         return;
525         }
526         if (end - 1 > ceiling - 1)
527                 return;
528 
529         pmd = pmd_offset(pud, start);
530         pud_clear(pud);
531         pmd_free_tlb(tlb, pmd, start);
532         mm_dec_nr_pmds(tlb->mm);
533 }
534 
535 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
536                                    unsigned long addr, unsigned long end,
537                                    unsigned long floor, unsigned long ceiling)
538 {
539         pud_t *pud;
540         unsigned long next;
541         unsigned long start;
542 
543         start = addr;
544         do {
545                 pud = pud_offset(pgd, addr);
546                 next = pud_addr_end(addr, end);
547                 if (!is_hugepd(__hugepd(pud_val(*pud)))) {
548                         if (pud_none_or_clear_bad(pud))
549                                 continue;
550                         hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
551                                                ceiling);
552                 } else {
553 #ifdef CONFIG_PPC_FSL_BOOK3E
554                         /*
555                          * Increment next by the size of the huge mapping since
556                          * there may be more than one entry at this level for a
557                          * single hugepage, but all of them point to
558                          * the same kmem cache that holds the hugepte.
559                          */
560                         next = addr + (1 << hugepd_shift(*(hugepd_t *)pud));
561 #endif
562                         free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
563                                           addr, next, floor, ceiling);
564                 }
565         } while (addr = next, addr != end);
566 
567         start &= PGDIR_MASK;
568         if (start < floor)
569                 return;
570         if (ceiling) {
571                 ceiling &= PGDIR_MASK;
572                 if (!ceiling)
573                         return;
574         }
575         if (end - 1 > ceiling - 1)
576                 return;
577 
578         pud = pud_offset(pgd, start);
579         pgd_clear(pgd);
580         pud_free_tlb(tlb, pud, start);
581 }
582 
583 /*
584  * This function frees user-level page tables of a process.
585  */
586 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
587                             unsigned long addr, unsigned long end,
588                             unsigned long floor, unsigned long ceiling)
589 {
590         pgd_t *pgd;
591         unsigned long next;
592 
593         /*
594          * Because there are a number of different possible pagetable
595          * layouts for hugepage ranges, we limit knowledge of how
596          * things should be laid out to the allocation path
597          * (huge_pte_alloc(), above).  Everything else works out the
598          * structure as it goes from information in the hugepd
599          * pointers.  That means that we can't here use the
600          * optimization used in the normal page free_pgd_range(), of
601          * checking whether we're actually covering a large enough
602          * range to have to do anything at the top level of the walk
603          * instead of at the bottom.
604          *
605          * To make sense of this, you should probably go read the big
606          * block comment at the top of the normal free_pgd_range(),
607          * too.
608          */
609 
610         do {
611                 next = pgd_addr_end(addr, end);
612                 pgd = pgd_offset(tlb->mm, addr);
613                 if (!is_hugepd(__hugepd(pgd_val(*pgd)))) {
614                         if (pgd_none_or_clear_bad(pgd))
615                                 continue;
616                         hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
617                 } else {
618 #ifdef CONFIG_PPC_FSL_BOOK3E
619                         /*
620                          * Increment next by the size of the huge mapping since
621                          * there may be more than one entry at the pgd level
622                          * for a single hugepage, but all of them point to the
623                          * same kmem cache that holds the hugepte.
624                          */
625                         next = addr + (1 << hugepd_shift(*(hugepd_t *)pgd));
626 #endif
627                         free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT,
628                                           addr, next, floor, ceiling);
629                 }
630         } while (addr = next, addr != end);
631 }
632 
633 /*
634  * We are holding mmap_sem, so a parallel huge page collapse cannot run.
635  * To prevent hugepage split, disable irq.
636  */
637 struct page *
638 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
639 {
640         bool is_thp;
641         pte_t *ptep, pte;
642         unsigned shift;
643         unsigned long mask, flags;
644         struct page *page = ERR_PTR(-EINVAL);
645 
646         local_irq_save(flags);
647         ptep = find_linux_pte_or_hugepte(mm->pgd, address, &is_thp, &shift);
648         if (!ptep)
649                 goto no_page;
650         pte = READ_ONCE(*ptep);
651         /*
652          * Verify it is a huge page else bail.
653          * Transparent hugepages are handled by generic code. We can skip them
654          * here.
655          */
656         if (!shift || is_thp)
657                 goto no_page;
658 
659         if (!pte_present(pte)) {
660                 page = NULL;
661                 goto no_page;
662         }
663         mask = (1UL << shift) - 1;
664         page = pte_page(pte);
665         if (page)
666                 page += (address & mask) / PAGE_SIZE;
667 
668 no_page:
669         local_irq_restore(flags);
670         return page;
671 }
672 
673 struct page *
674 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
675                 pmd_t *pmd, int write)
676 {
677         BUG();
678         return NULL;
679 }
680 
681 struct page *
682 follow_huge_pud(struct mm_struct *mm, unsigned long address,
683                 pud_t *pud, int write)
684 {
685         BUG();
686         return NULL;
687 }
688 
689 static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
690                                       unsigned long sz)
691 {
692         unsigned long __boundary = (addr + sz) & ~(sz-1);
693         return (__boundary - 1 < end - 1) ? __boundary : end;
694 }
695 
696 int gup_huge_pd(hugepd_t hugepd, unsigned long addr, unsigned pdshift,
697                 unsigned long end, int write, struct page **pages, int *nr)
698 {
699         pte_t *ptep;
700         unsigned long sz = 1UL << hugepd_shift(hugepd);
701         unsigned long next;
702 
703         ptep = hugepte_offset(hugepd, addr, pdshift);
704         do {
705                 next = hugepte_addr_end(addr, end, sz);
706                 if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr))
707                         return 0;
708         } while (ptep++, addr = next, addr != end);
709 
710         return 1;
711 }
712 
713 #ifdef CONFIG_PPC_MM_SLICES
714 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
715                                         unsigned long len, unsigned long pgoff,
716                                         unsigned long flags)
717 {
718         struct hstate *hstate = hstate_file(file);
719         int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
720 
721         if (radix_enabled())
722                 return radix__hugetlb_get_unmapped_area(file, addr, len,
723                                                        pgoff, flags);
724         return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1);
725 }
726 #endif
727 
728 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
729 {
730 #ifdef CONFIG_PPC_MM_SLICES
731         unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
732         /* With radix we don't use slice, so derive it from vma*/
733         if (!radix_enabled())
734                 return 1UL << mmu_psize_to_shift(psize);
735 #endif
736         if (!is_vm_hugetlb_page(vma))
737                 return PAGE_SIZE;
738 
739         return huge_page_size(hstate_vma(vma));
740 }
741 
742 static inline bool is_power_of_4(unsigned long x)
743 {
744         if (is_power_of_2(x))
745                 return (__ilog2(x) % 2) ? false : true;
746         return false;
747 }
748 
749 static int __init add_huge_page_size(unsigned long long size)
750 {
751         int shift = __ffs(size);
752         int mmu_psize;
753 
754         /* Check that it is a page size supported by the hardware and
755          * that it fits within pagetable and slice limits. */
756 #ifdef CONFIG_PPC_FSL_BOOK3E
757         if ((size < PAGE_SIZE) || !is_power_of_4(size))
758                 return -EINVAL;
759 #else
760         if (!is_power_of_2(size)
761             || (shift > SLICE_HIGH_SHIFT) || (shift <= PAGE_SHIFT))
762                 return -EINVAL;
763 #endif
764 
765         if ((mmu_psize = shift_to_mmu_psize(shift)) < 0)
766                 return -EINVAL;
767 
768         BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
769 
770         /* Return if huge page size has already been setup */
771         if (size_to_hstate(size))
772                 return 0;
773 
774         hugetlb_add_hstate(shift - PAGE_SHIFT);
775 
776         return 0;
777 }
778 
779 static int __init hugepage_setup_sz(char *str)
780 {
781         unsigned long long size;
782 
783         size = memparse(str, &str);
784 
785         if (add_huge_page_size(size) != 0) {
786                 hugetlb_bad_size();
787                 pr_err("Invalid huge page size specified(%llu)\n", size);
788         }
789 
790         return 1;
791 }
792 __setup("hugepagesz=", hugepage_setup_sz);
793 
794 #ifdef CONFIG_PPC_FSL_BOOK3E
795 struct kmem_cache *hugepte_cache;
796 static int __init hugetlbpage_init(void)
797 {
798         int psize;
799 
800         for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
801                 unsigned shift;
802 
803                 if (!mmu_psize_defs[psize].shift)
804                         continue;
805 
806                 shift = mmu_psize_to_shift(psize);
807 
808                 /* Don't treat normal page sizes as huge... */
809                 if (shift != PAGE_SHIFT)
810                         if (add_huge_page_size(1ULL << shift) < 0)
811                                 continue;
812         }
813 
814         /*
815          * Create a kmem cache for hugeptes.  The bottom bits in the pte have
816          * size information encoded in them, so align them to allow this
817          */
818         hugepte_cache =  kmem_cache_create("hugepte-cache", sizeof(pte_t),
819                                            HUGEPD_SHIFT_MASK + 1, 0, NULL);
820         if (hugepte_cache == NULL)
821                 panic("%s: Unable to create kmem cache for hugeptes\n",
822                       __func__);
823 
824         /* Default hpage size = 4M */
825         if (mmu_psize_defs[MMU_PAGE_4M].shift)
826                 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_4M].shift;
827         else
828                 panic("%s: Unable to set default huge page size\n", __func__);
829 
830 
831         return 0;
832 }
833 #else
834 static int __init hugetlbpage_init(void)
835 {
836         int psize;
837 
838         if (!radix_enabled() && !mmu_has_feature(MMU_FTR_16M_PAGE))
839                 return -ENODEV;
840 
841         for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
842                 unsigned shift;
843                 unsigned pdshift;
844 
845                 if (!mmu_psize_defs[psize].shift)
846                         continue;
847 
848                 shift = mmu_psize_to_shift(psize);
849 
850                 if (add_huge_page_size(1ULL << shift) < 0)
851                         continue;
852 
853                 if (shift < PMD_SHIFT)
854                         pdshift = PMD_SHIFT;
855                 else if (shift < PUD_SHIFT)
856                         pdshift = PUD_SHIFT;
857                 else
858                         pdshift = PGDIR_SHIFT;
859                 /*
860                  * if we have pdshift and shift value same, we don't
861                  * use pgt cache for hugepd.
862                  */
863                 if (pdshift != shift) {
864                         pgtable_cache_add(pdshift - shift, NULL);
865                         if (!PGT_CACHE(pdshift - shift))
866                                 panic("hugetlbpage_init(): could not create "
867                                       "pgtable cache for %d bit pagesize\n", shift);
868                 }
869         }
870 
871         /* Set default large page size. Currently, we pick 16M or 1M
872          * depending on what is available
873          */
874         if (mmu_psize_defs[MMU_PAGE_16M].shift)
875                 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_16M].shift;
876         else if (mmu_psize_defs[MMU_PAGE_1M].shift)
877                 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_1M].shift;
878         else if (mmu_psize_defs[MMU_PAGE_2M].shift)
879                 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_2M].shift;
880 
881 
882         return 0;
883 }
884 #endif
885 arch_initcall(hugetlbpage_init);
886 
887 void flush_dcache_icache_hugepage(struct page *page)
888 {
889         int i;
890         void *start;
891 
892         BUG_ON(!PageCompound(page));
893 
894         for (i = 0; i < (1UL << compound_order(page)); i++) {
895                 if (!PageHighMem(page)) {
896                         __flush_dcache_icache(page_address(page+i));
897                 } else {
898                         start = kmap_atomic(page+i);
899                         __flush_dcache_icache(start);
900                         kunmap_atomic(start);
901                 }
902         }
903 }
904 
905 #endif /* CONFIG_HUGETLB_PAGE */
906 
907 /*
908  * We have 4 cases for pgds and pmds:
909  * (1) invalid (all zeroes)
910  * (2) pointer to next table, as normal; bottom 6 bits == 0
911  * (3) leaf pte for huge page _PAGE_PTE set
912  * (4) hugepd pointer, _PAGE_PTE = 0 and bits [2..6] indicate size of table
913  *
914  * So long as we atomically load page table pointers we are safe against teardown,
915  * we can follow the address down to the the page and take a ref on it.
916  * This function need to be called with interrupts disabled. We use this variant
917  * when we have MSR[EE] = 0 but the paca->soft_enabled = 1
918  */
919 
920 pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
921                                    bool *is_thp, unsigned *shift)
922 {
923         pgd_t pgd, *pgdp;
924         pud_t pud, *pudp;
925         pmd_t pmd, *pmdp;
926         pte_t *ret_pte;
927         hugepd_t *hpdp = NULL;
928         unsigned pdshift = PGDIR_SHIFT;
929 
930         if (shift)
931                 *shift = 0;
932 
933         if (is_thp)
934                 *is_thp = false;
935 
936         pgdp = pgdir + pgd_index(ea);
937         pgd  = READ_ONCE(*pgdp);
938         /*
939          * Always operate on the local stack value. This make sure the
940          * value don't get updated by a parallel THP split/collapse,
941          * page fault or a page unmap. The return pte_t * is still not
942          * stable. So should be checked there for above conditions.
943          */
944         if (pgd_none(pgd))
945                 return NULL;
946         else if (pgd_huge(pgd)) {
947                 ret_pte = (pte_t *) pgdp;
948                 goto out;
949         } else if (is_hugepd(__hugepd(pgd_val(pgd))))
950                 hpdp = (hugepd_t *)&pgd;
951         else {
952                 /*
953                  * Even if we end up with an unmap, the pgtable will not
954                  * be freed, because we do an rcu free and here we are
955                  * irq disabled
956                  */
957                 pdshift = PUD_SHIFT;
958                 pudp = pud_offset(&pgd, ea);
959                 pud  = READ_ONCE(*pudp);
960 
961                 if (pud_none(pud))
962                         return NULL;
963                 else if (pud_huge(pud)) {
964                         ret_pte = (pte_t *) pudp;
965                         goto out;
966                 } else if (is_hugepd(__hugepd(pud_val(pud))))
967                         hpdp = (hugepd_t *)&pud;
968                 else {
969                         pdshift = PMD_SHIFT;
970                         pmdp = pmd_offset(&pud, ea);
971                         pmd  = READ_ONCE(*pmdp);
972                         /*
973                          * A hugepage collapse is captured by pmd_none, because
974                          * it mark the pmd none and do a hpte invalidate.
975                          */
976                         if (pmd_none(pmd))
977                                 return NULL;
978 
979                         if (pmd_trans_huge(pmd)) {
980                                 if (is_thp)
981                                         *is_thp = true;
982                                 ret_pte = (pte_t *) pmdp;
983                                 goto out;
984                         }
985 
986                         if (pmd_huge(pmd)) {
987                                 ret_pte = (pte_t *) pmdp;
988                                 goto out;
989                         } else if (is_hugepd(__hugepd(pmd_val(pmd))))
990                                 hpdp = (hugepd_t *)&pmd;
991                         else
992                                 return pte_offset_kernel(&pmd, ea);
993                 }
994         }
995         if (!hpdp)
996                 return NULL;
997 
998         ret_pte = hugepte_offset(*hpdp, ea, pdshift);
999         pdshift = hugepd_shift(*hpdp);
1000 out:
1001         if (shift)
1002                 *shift = pdshift;
1003         return ret_pte;
1004 }
1005 EXPORT_SYMBOL_GPL(__find_linux_pte_or_hugepte);
1006 
1007 int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
1008                 unsigned long end, int write, struct page **pages, int *nr)
1009 {
1010         unsigned long mask;
1011         unsigned long pte_end;
1012         struct page *head, *page;
1013         pte_t pte;
1014         int refs;
1015 
1016         pte_end = (addr + sz) & ~(sz-1);
1017         if (pte_end < end)
1018                 end = pte_end;
1019 
1020         pte = READ_ONCE(*ptep);
1021         mask = _PAGE_PRESENT | _PAGE_READ;
1022 
1023         /*
1024          * On some CPUs like the 8xx, _PAGE_RW hence _PAGE_WRITE is defined
1025          * as 0 and _PAGE_RO has to be set when a page is not writable
1026          */
1027         if (write)
1028                 mask |= _PAGE_WRITE;
1029         else
1030                 mask |= _PAGE_RO;
1031 
1032         if ((pte_val(pte) & mask) != mask)
1033                 return 0;
1034 
1035         /* hugepages are never "special" */
1036         VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
1037 
1038         refs = 0;
1039         head = pte_page(pte);
1040 
1041         page = head + ((addr & (sz-1)) >> PAGE_SHIFT);
1042         do {
1043                 VM_BUG_ON(compound_head(page) != head);
1044                 pages[*nr] = page;
1045                 (*nr)++;
1046                 page++;
1047                 refs++;
1048         } while (addr += PAGE_SIZE, addr != end);
1049 
1050         if (!page_cache_add_speculative(head, refs)) {
1051                 *nr -= refs;
1052                 return 0;
1053         }
1054 
1055         if (unlikely(pte_val(pte) != pte_val(*ptep))) {
1056                 /* Could be optimized better */
1057                 *nr -= refs;
1058                 while (refs--)
1059                         put_page(head);
1060                 return 0;
1061         }
1062 
1063         return 1;
1064 }
1065 

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