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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 
 25 #define PAGE_SHIFT_64K  16
 26 #define PAGE_SHIFT_16M  24
 27 #define PAGE_SHIFT_16G  34
 28 
 29 unsigned int HPAGE_SHIFT;
 30 
 31 /*
 32  * Tracks gpages after the device tree is scanned and before the
 33  * huge_boot_pages list is ready.  On non-Freescale implementations, this is
 34  * just used to track 16G pages and so is a single array.  FSL-based
 35  * implementations may have more than one gpage size, so we need multiple
 36  * arrays
 37  */
 38 #ifdef CONFIG_PPC_FSL_BOOK3E
 39 #define MAX_NUMBER_GPAGES       128
 40 struct psize_gpages {
 41         u64 gpage_list[MAX_NUMBER_GPAGES];
 42         unsigned int nr_gpages;
 43 };
 44 static struct psize_gpages gpage_freearray[MMU_PAGE_COUNT];
 45 #else
 46 #define MAX_NUMBER_GPAGES       1024
 47 static u64 gpage_freearray[MAX_NUMBER_GPAGES];
 48 static unsigned nr_gpages;
 49 #endif
 50 
 51 static inline int shift_to_mmu_psize(unsigned int shift)
 52 {
 53         int psize;
 54 
 55         for (psize = 0; psize < MMU_PAGE_COUNT; ++psize)
 56                 if (mmu_psize_defs[psize].shift == shift)
 57                         return psize;
 58         return -1;
 59 }
 60 
 61 static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
 62 {
 63         if (mmu_psize_defs[mmu_psize].shift)
 64                 return mmu_psize_defs[mmu_psize].shift;
 65         BUG();
 66 }
 67 
 68 #define hugepd_none(hpd)        ((hpd).pd == 0)
 69 
 70 pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift)
 71 {
 72         pgd_t *pg;
 73         pud_t *pu;
 74         pmd_t *pm;
 75         hugepd_t *hpdp = NULL;
 76         unsigned pdshift = PGDIR_SHIFT;
 77 
 78         if (shift)
 79                 *shift = 0;
 80 
 81         pg = pgdir + pgd_index(ea);
 82         if (is_hugepd(pg)) {
 83                 hpdp = (hugepd_t *)pg;
 84         } else if (!pgd_none(*pg)) {
 85                 pdshift = PUD_SHIFT;
 86                 pu = pud_offset(pg, ea);
 87                 if (is_hugepd(pu))
 88                         hpdp = (hugepd_t *)pu;
 89                 else if (!pud_none(*pu)) {
 90                         pdshift = PMD_SHIFT;
 91                         pm = pmd_offset(pu, ea);
 92                         if (is_hugepd(pm))
 93                                 hpdp = (hugepd_t *)pm;
 94                         else if (!pmd_none(*pm)) {
 95                                 return pte_offset_kernel(pm, ea);
 96                         }
 97                 }
 98         }
 99 
100         if (!hpdp)
101                 return NULL;
102 
103         if (shift)
104                 *shift = hugepd_shift(*hpdp);
105         return hugepte_offset(hpdp, ea, pdshift);
106 }
107 EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte);
108 
109 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
110 {
111         return find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
112 }
113 
114 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
115                            unsigned long address, unsigned pdshift, unsigned pshift)
116 {
117         struct kmem_cache *cachep;
118         pte_t *new;
119 
120 #ifdef CONFIG_PPC_FSL_BOOK3E
121         int i;
122         int num_hugepd = 1 << (pshift - pdshift);
123         cachep = hugepte_cache;
124 #else
125         cachep = PGT_CACHE(pdshift - pshift);
126 #endif
127 
128         new = kmem_cache_zalloc(cachep, GFP_KERNEL|__GFP_REPEAT);
129 
130         BUG_ON(pshift > HUGEPD_SHIFT_MASK);
131         BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);
132 
133         if (! new)
134                 return -ENOMEM;
135 
136         spin_lock(&mm->page_table_lock);
137 #ifdef CONFIG_PPC_FSL_BOOK3E
138         /*
139          * We have multiple higher-level entries that point to the same
140          * actual pte location.  Fill in each as we go and backtrack on error.
141          * We need all of these so the DTLB pgtable walk code can find the
142          * right higher-level entry without knowing if it's a hugepage or not.
143          */
144         for (i = 0; i < num_hugepd; i++, hpdp++) {
145                 if (unlikely(!hugepd_none(*hpdp)))
146                         break;
147                 else
148                         hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift;
149         }
150         /* If we bailed from the for loop early, an error occurred, clean up */
151         if (i < num_hugepd) {
152                 for (i = i - 1 ; i >= 0; i--, hpdp--)
153                         hpdp->pd = 0;
154                 kmem_cache_free(cachep, new);
155         }
156 #else
157         if (!hugepd_none(*hpdp))
158                 kmem_cache_free(cachep, new);
159         else
160                 hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift;
161 #endif
162         spin_unlock(&mm->page_table_lock);
163         return 0;
164 }
165 
166 /*
167  * These macros define how to determine which level of the page table holds
168  * the hpdp.
169  */
170 #ifdef CONFIG_PPC_FSL_BOOK3E
171 #define HUGEPD_PGD_SHIFT PGDIR_SHIFT
172 #define HUGEPD_PUD_SHIFT PUD_SHIFT
173 #else
174 #define HUGEPD_PGD_SHIFT PUD_SHIFT
175 #define HUGEPD_PUD_SHIFT PMD_SHIFT
176 #endif
177 
178 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
179 {
180         pgd_t *pg;
181         pud_t *pu;
182         pmd_t *pm;
183         hugepd_t *hpdp = NULL;
184         unsigned pshift = __ffs(sz);
185         unsigned pdshift = PGDIR_SHIFT;
186 
187         addr &= ~(sz-1);
188 
189         pg = pgd_offset(mm, addr);
190 
191         if (pshift >= HUGEPD_PGD_SHIFT) {
192                 hpdp = (hugepd_t *)pg;
193         } else {
194                 pdshift = PUD_SHIFT;
195                 pu = pud_alloc(mm, pg, addr);
196                 if (pshift >= HUGEPD_PUD_SHIFT) {
197                         hpdp = (hugepd_t *)pu;
198                 } else {
199                         pdshift = PMD_SHIFT;
200                         pm = pmd_alloc(mm, pu, addr);
201                         hpdp = (hugepd_t *)pm;
202                 }
203         }
204 
205         if (!hpdp)
206                 return NULL;
207 
208         BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
209 
210         if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift))
211                 return NULL;
212 
213         return hugepte_offset(hpdp, addr, pdshift);
214 }
215 
216 #ifdef CONFIG_PPC_FSL_BOOK3E
217 /* Build list of addresses of gigantic pages.  This function is used in early
218  * boot before the buddy or bootmem allocator is setup.
219  */
220 void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
221 {
222         unsigned int idx = shift_to_mmu_psize(__ffs(page_size));
223         int i;
224 
225         if (addr == 0)
226                 return;
227 
228         gpage_freearray[idx].nr_gpages = number_of_pages;
229 
230         for (i = 0; i < number_of_pages; i++) {
231                 gpage_freearray[idx].gpage_list[i] = addr;
232                 addr += page_size;
233         }
234 }
235 
236 /*
237  * Moves the gigantic page addresses from the temporary list to the
238  * huge_boot_pages list.
239  */
240 int alloc_bootmem_huge_page(struct hstate *hstate)
241 {
242         struct huge_bootmem_page *m;
243         int idx = shift_to_mmu_psize(hstate->order + PAGE_SHIFT);
244         int nr_gpages = gpage_freearray[idx].nr_gpages;
245 
246         if (nr_gpages == 0)
247                 return 0;
248 
249 #ifdef CONFIG_HIGHMEM
250         /*
251          * If gpages can be in highmem we can't use the trick of storing the
252          * data structure in the page; allocate space for this
253          */
254         m = alloc_bootmem(sizeof(struct huge_bootmem_page));
255         m->phys = gpage_freearray[idx].gpage_list[--nr_gpages];
256 #else
257         m = phys_to_virt(gpage_freearray[idx].gpage_list[--nr_gpages]);
258 #endif
259 
260         list_add(&m->list, &huge_boot_pages);
261         gpage_freearray[idx].nr_gpages = nr_gpages;
262         gpage_freearray[idx].gpage_list[nr_gpages] = 0;
263         m->hstate = hstate;
264 
265         return 1;
266 }
267 /*
268  * Scan the command line hugepagesz= options for gigantic pages; store those in
269  * a list that we use to allocate the memory once all options are parsed.
270  */
271 
272 unsigned long gpage_npages[MMU_PAGE_COUNT];
273 
274 static int __init do_gpage_early_setup(char *param, char *val,
275                                        const char *unused)
276 {
277         static phys_addr_t size;
278         unsigned long npages;
279 
280         /*
281          * The hugepagesz and hugepages cmdline options are interleaved.  We
282          * use the size variable to keep track of whether or not this was done
283          * properly and skip over instances where it is incorrect.  Other
284          * command-line parsing code will issue warnings, so we don't need to.
285          *
286          */
287         if ((strcmp(param, "default_hugepagesz") == 0) ||
288             (strcmp(param, "hugepagesz") == 0)) {
289                 size = memparse(val, NULL);
290         } else if (strcmp(param, "hugepages") == 0) {
291                 if (size != 0) {
292                         if (sscanf(val, "%lu", &npages) <= 0)
293                                 npages = 0;
294                         gpage_npages[shift_to_mmu_psize(__ffs(size))] = npages;
295                         size = 0;
296                 }
297         }
298         return 0;
299 }
300 
301 
302 /*
303  * This function allocates physical space for pages that are larger than the
304  * buddy allocator can handle.  We want to allocate these in highmem because
305  * the amount of lowmem is limited.  This means that this function MUST be
306  * called before lowmem_end_addr is set up in MMU_init() in order for the lmb
307  * allocate to grab highmem.
308  */
309 void __init reserve_hugetlb_gpages(void)
310 {
311         static __initdata char cmdline[COMMAND_LINE_SIZE];
312         phys_addr_t size, base;
313         int i;
314 
315         strlcpy(cmdline, boot_command_line, COMMAND_LINE_SIZE);
316         parse_args("hugetlb gpages", cmdline, NULL, 0, 0, 0,
317                         &do_gpage_early_setup);
318 
319         /*
320          * Walk gpage list in reverse, allocating larger page sizes first.
321          * Skip over unsupported sizes, or sizes that have 0 gpages allocated.
322          * When we reach the point in the list where pages are no longer
323          * considered gpages, we're done.
324          */
325         for (i = MMU_PAGE_COUNT-1; i >= 0; i--) {
326                 if (mmu_psize_defs[i].shift == 0 || gpage_npages[i] == 0)
327                         continue;
328                 else if (mmu_psize_to_shift(i) < (MAX_ORDER + PAGE_SHIFT))
329                         break;
330 
331                 size = (phys_addr_t)(1ULL << mmu_psize_to_shift(i));
332                 base = memblock_alloc_base(size * gpage_npages[i], size,
333                                            MEMBLOCK_ALLOC_ANYWHERE);
334                 add_gpage(base, size, gpage_npages[i]);
335         }
336 }
337 
338 #else /* !PPC_FSL_BOOK3E */
339 
340 /* Build list of addresses of gigantic pages.  This function is used in early
341  * boot before the buddy or bootmem allocator is setup.
342  */
343 void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
344 {
345         if (!addr)
346                 return;
347         while (number_of_pages > 0) {
348                 gpage_freearray[nr_gpages] = addr;
349                 nr_gpages++;
350                 number_of_pages--;
351                 addr += page_size;
352         }
353 }
354 
355 /* Moves the gigantic page addresses from the temporary list to the
356  * huge_boot_pages list.
357  */
358 int alloc_bootmem_huge_page(struct hstate *hstate)
359 {
360         struct huge_bootmem_page *m;
361         if (nr_gpages == 0)
362                 return 0;
363         m = phys_to_virt(gpage_freearray[--nr_gpages]);
364         gpage_freearray[nr_gpages] = 0;
365         list_add(&m->list, &huge_boot_pages);
366         m->hstate = hstate;
367         return 1;
368 }
369 #endif
370 
371 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
372 {
373         return 0;
374 }
375 
376 #ifdef CONFIG_PPC_FSL_BOOK3E
377 #define HUGEPD_FREELIST_SIZE \
378         ((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))
379 
380 struct hugepd_freelist {
381         struct rcu_head rcu;
382         unsigned int index;
383         void *ptes[0];
384 };
385 
386 static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur);
387 
388 static void hugepd_free_rcu_callback(struct rcu_head *head)
389 {
390         struct hugepd_freelist *batch =
391                 container_of(head, struct hugepd_freelist, rcu);
392         unsigned int i;
393 
394         for (i = 0; i < batch->index; i++)
395                 kmem_cache_free(hugepte_cache, batch->ptes[i]);
396 
397         free_page((unsigned long)batch);
398 }
399 
400 static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
401 {
402         struct hugepd_freelist **batchp;
403 
404         batchp = &__get_cpu_var(hugepd_freelist_cur);
405 
406         if (atomic_read(&tlb->mm->mm_users) < 2 ||
407             cpumask_equal(mm_cpumask(tlb->mm),
408                           cpumask_of(smp_processor_id()))) {
409                 kmem_cache_free(hugepte_cache, hugepte);
410                 return;
411         }
412 
413         if (*batchp == NULL) {
414                 *batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC);
415                 (*batchp)->index = 0;
416         }
417 
418         (*batchp)->ptes[(*batchp)->index++] = hugepte;
419         if ((*batchp)->index == HUGEPD_FREELIST_SIZE) {
420                 call_rcu_sched(&(*batchp)->rcu, hugepd_free_rcu_callback);
421                 *batchp = NULL;
422         }
423 }
424 #endif
425 
426 static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift,
427                               unsigned long start, unsigned long end,
428                               unsigned long floor, unsigned long ceiling)
429 {
430         pte_t *hugepte = hugepd_page(*hpdp);
431         int i;
432 
433         unsigned long pdmask = ~((1UL << pdshift) - 1);
434         unsigned int num_hugepd = 1;
435 
436 #ifdef CONFIG_PPC_FSL_BOOK3E
437         /* Note: On fsl the hpdp may be the first of several */
438         num_hugepd = (1 << (hugepd_shift(*hpdp) - pdshift));
439 #else
440         unsigned int shift = hugepd_shift(*hpdp);
441 #endif
442 
443         start &= pdmask;
444         if (start < floor)
445                 return;
446         if (ceiling) {
447                 ceiling &= pdmask;
448                 if (! ceiling)
449                         return;
450         }
451         if (end - 1 > ceiling - 1)
452                 return;
453 
454         for (i = 0; i < num_hugepd; i++, hpdp++)
455                 hpdp->pd = 0;
456 
457         tlb->need_flush = 1;
458 
459 #ifdef CONFIG_PPC_FSL_BOOK3E
460         hugepd_free(tlb, hugepte);
461 #else
462         pgtable_free_tlb(tlb, hugepte, pdshift - shift);
463 #endif
464 }
465 
466 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
467                                    unsigned long addr, unsigned long end,
468                                    unsigned long floor, unsigned long ceiling)
469 {
470         pmd_t *pmd;
471         unsigned long next;
472         unsigned long start;
473 
474         start = addr;
475         do {
476                 pmd = pmd_offset(pud, addr);
477                 next = pmd_addr_end(addr, end);
478                 if (pmd_none(*pmd))
479                         continue;
480 #ifdef CONFIG_PPC_FSL_BOOK3E
481                 /*
482                  * Increment next by the size of the huge mapping since
483                  * there may be more than one entry at this level for a
484                  * single hugepage, but all of them point to
485                  * the same kmem cache that holds the hugepte.
486                  */
487                 next = addr + (1 << hugepd_shift(*(hugepd_t *)pmd));
488 #endif
489                 free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
490                                   addr, next, floor, ceiling);
491         } while (addr = next, addr != end);
492 
493         start &= PUD_MASK;
494         if (start < floor)
495                 return;
496         if (ceiling) {
497                 ceiling &= PUD_MASK;
498                 if (!ceiling)
499                         return;
500         }
501         if (end - 1 > ceiling - 1)
502                 return;
503 
504         pmd = pmd_offset(pud, start);
505         pud_clear(pud);
506         pmd_free_tlb(tlb, pmd, start);
507 }
508 
509 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
510                                    unsigned long addr, unsigned long end,
511                                    unsigned long floor, unsigned long ceiling)
512 {
513         pud_t *pud;
514         unsigned long next;
515         unsigned long start;
516 
517         start = addr;
518         do {
519                 pud = pud_offset(pgd, addr);
520                 next = pud_addr_end(addr, end);
521                 if (!is_hugepd(pud)) {
522                         if (pud_none_or_clear_bad(pud))
523                                 continue;
524                         hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
525                                                ceiling);
526                 } else {
527 #ifdef CONFIG_PPC_FSL_BOOK3E
528                         /*
529                          * Increment next by the size of the huge mapping since
530                          * there may be more than one entry at this level for a
531                          * single hugepage, but all of them point to
532                          * the same kmem cache that holds the hugepte.
533                          */
534                         next = addr + (1 << hugepd_shift(*(hugepd_t *)pud));
535 #endif
536                         free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
537                                           addr, next, floor, ceiling);
538                 }
539         } while (addr = next, addr != end);
540 
541         start &= PGDIR_MASK;
542         if (start < floor)
543                 return;
544         if (ceiling) {
545                 ceiling &= PGDIR_MASK;
546                 if (!ceiling)
547                         return;
548         }
549         if (end - 1 > ceiling - 1)
550                 return;
551 
552         pud = pud_offset(pgd, start);
553         pgd_clear(pgd);
554         pud_free_tlb(tlb, pud, start);
555 }
556 
557 /*
558  * This function frees user-level page tables of a process.
559  *
560  * Must be called with pagetable lock held.
561  */
562 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
563                             unsigned long addr, unsigned long end,
564                             unsigned long floor, unsigned long ceiling)
565 {
566         pgd_t *pgd;
567         unsigned long next;
568 
569         /*
570          * Because there are a number of different possible pagetable
571          * layouts for hugepage ranges, we limit knowledge of how
572          * things should be laid out to the allocation path
573          * (huge_pte_alloc(), above).  Everything else works out the
574          * structure as it goes from information in the hugepd
575          * pointers.  That means that we can't here use the
576          * optimization used in the normal page free_pgd_range(), of
577          * checking whether we're actually covering a large enough
578          * range to have to do anything at the top level of the walk
579          * instead of at the bottom.
580          *
581          * To make sense of this, you should probably go read the big
582          * block comment at the top of the normal free_pgd_range(),
583          * too.
584          */
585 
586         do {
587                 next = pgd_addr_end(addr, end);
588                 pgd = pgd_offset(tlb->mm, addr);
589                 if (!is_hugepd(pgd)) {
590                         if (pgd_none_or_clear_bad(pgd))
591                                 continue;
592                         hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
593                 } else {
594 #ifdef CONFIG_PPC_FSL_BOOK3E
595                         /*
596                          * Increment next by the size of the huge mapping since
597                          * there may be more than one entry at the pgd level
598                          * for a single hugepage, but all of them point to the
599                          * same kmem cache that holds the hugepte.
600                          */
601                         next = addr + (1 << hugepd_shift(*(hugepd_t *)pgd));
602 #endif
603                         free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT,
604                                           addr, next, floor, ceiling);
605                 }
606         } while (addr = next, addr != end);
607 }
608 
609 struct page *
610 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
611 {
612         pte_t *ptep;
613         struct page *page;
614         unsigned shift;
615         unsigned long mask;
616 
617         ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift);
618 
619         /* Verify it is a huge page else bail. */
620         if (!ptep || !shift)
621                 return ERR_PTR(-EINVAL);
622 
623         mask = (1UL << shift) - 1;
624         page = pte_page(*ptep);
625         if (page)
626                 page += (address & mask) / PAGE_SIZE;
627 
628         return page;
629 }
630 
631 int pmd_huge(pmd_t pmd)
632 {
633         return 0;
634 }
635 
636 int pud_huge(pud_t pud)
637 {
638         return 0;
639 }
640 
641 struct page *
642 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
643                 pmd_t *pmd, int write)
644 {
645         BUG();
646         return NULL;
647 }
648 
649 static noinline int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
650                        unsigned long end, int write, struct page **pages, int *nr)
651 {
652         unsigned long mask;
653         unsigned long pte_end;
654         struct page *head, *page, *tail;
655         pte_t pte;
656         int refs;
657 
658         pte_end = (addr + sz) & ~(sz-1);
659         if (pte_end < end)
660                 end = pte_end;
661 
662         pte = *ptep;
663         mask = _PAGE_PRESENT | _PAGE_USER;
664         if (write)
665                 mask |= _PAGE_RW;
666 
667         if ((pte_val(pte) & mask) != mask)
668                 return 0;
669 
670         /* hugepages are never "special" */
671         VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
672 
673         refs = 0;
674         head = pte_page(pte);
675 
676         page = head + ((addr & (sz-1)) >> PAGE_SHIFT);
677         tail = page;
678         do {
679                 VM_BUG_ON(compound_head(page) != head);
680                 pages[*nr] = page;
681                 (*nr)++;
682                 page++;
683                 refs++;
684         } while (addr += PAGE_SIZE, addr != end);
685 
686         if (!page_cache_add_speculative(head, refs)) {
687                 *nr -= refs;
688                 return 0;
689         }
690 
691         if (unlikely(pte_val(pte) != pte_val(*ptep))) {
692                 /* Could be optimized better */
693                 *nr -= refs;
694                 while (refs--)
695                         put_page(head);
696                 return 0;
697         }
698 
699         /*
700          * Any tail page need their mapcount reference taken before we
701          * return.
702          */
703         while (refs--) {
704                 if (PageTail(tail))
705                         get_huge_page_tail(tail);
706                 tail++;
707         }
708 
709         return 1;
710 }
711 
712 static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
713                                       unsigned long sz)
714 {
715         unsigned long __boundary = (addr + sz) & ~(sz-1);
716         return (__boundary - 1 < end - 1) ? __boundary : end;
717 }
718 
719 int gup_hugepd(hugepd_t *hugepd, unsigned pdshift,
720                unsigned long addr, unsigned long end,
721                int write, struct page **pages, int *nr)
722 {
723         pte_t *ptep;
724         unsigned long sz = 1UL << hugepd_shift(*hugepd);
725         unsigned long next;
726 
727         ptep = hugepte_offset(hugepd, addr, pdshift);
728         do {
729                 next = hugepte_addr_end(addr, end, sz);
730                 if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr))
731                         return 0;
732         } while (ptep++, addr = next, addr != end);
733 
734         return 1;
735 }
736 
737 #ifdef CONFIG_PPC_MM_SLICES
738 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
739                                         unsigned long len, unsigned long pgoff,
740                                         unsigned long flags)
741 {
742         struct hstate *hstate = hstate_file(file);
743         int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
744 
745         return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1, 0);
746 }
747 #endif
748 
749 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
750 {
751 #ifdef CONFIG_PPC_MM_SLICES
752         unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
753 
754         return 1UL << mmu_psize_to_shift(psize);
755 #else
756         if (!is_vm_hugetlb_page(vma))
757                 return PAGE_SIZE;
758 
759         return huge_page_size(hstate_vma(vma));
760 #endif
761 }
762 
763 static inline bool is_power_of_4(unsigned long x)
764 {
765         if (is_power_of_2(x))
766                 return (__ilog2(x) % 2) ? false : true;
767         return false;
768 }
769 
770 static int __init add_huge_page_size(unsigned long long size)
771 {
772         int shift = __ffs(size);
773         int mmu_psize;
774 
775         /* Check that it is a page size supported by the hardware and
776          * that it fits within pagetable and slice limits. */
777 #ifdef CONFIG_PPC_FSL_BOOK3E
778         if ((size < PAGE_SIZE) || !is_power_of_4(size))
779                 return -EINVAL;
780 #else
781         if (!is_power_of_2(size)
782             || (shift > SLICE_HIGH_SHIFT) || (shift <= PAGE_SHIFT))
783                 return -EINVAL;
784 #endif
785 
786         if ((mmu_psize = shift_to_mmu_psize(shift)) < 0)
787                 return -EINVAL;
788 
789 #ifdef CONFIG_SPU_FS_64K_LS
790         /* Disable support for 64K huge pages when 64K SPU local store
791          * support is enabled as the current implementation conflicts.
792          */
793         if (shift == PAGE_SHIFT_64K)
794                 return -EINVAL;
795 #endif /* CONFIG_SPU_FS_64K_LS */
796 
797         BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
798 
799         /* Return if huge page size has already been setup */
800         if (size_to_hstate(size))
801                 return 0;
802 
803         hugetlb_add_hstate(shift - PAGE_SHIFT);
804 
805         return 0;
806 }
807 
808 static int __init hugepage_setup_sz(char *str)
809 {
810         unsigned long long size;
811 
812         size = memparse(str, &str);
813 
814         if (add_huge_page_size(size) != 0)
815                 printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size);
816 
817         return 1;
818 }
819 __setup("hugepagesz=", hugepage_setup_sz);
820 
821 #ifdef CONFIG_PPC_FSL_BOOK3E
822 struct kmem_cache *hugepte_cache;
823 static int __init hugetlbpage_init(void)
824 {
825         int psize;
826 
827         for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
828                 unsigned shift;
829 
830                 if (!mmu_psize_defs[psize].shift)
831                         continue;
832 
833                 shift = mmu_psize_to_shift(psize);
834 
835                 /* Don't treat normal page sizes as huge... */
836                 if (shift != PAGE_SHIFT)
837                         if (add_huge_page_size(1ULL << shift) < 0)
838                                 continue;
839         }
840 
841         /*
842          * Create a kmem cache for hugeptes.  The bottom bits in the pte have
843          * size information encoded in them, so align them to allow this
844          */
845         hugepte_cache =  kmem_cache_create("hugepte-cache", sizeof(pte_t),
846                                            HUGEPD_SHIFT_MASK + 1, 0, NULL);
847         if (hugepte_cache == NULL)
848                 panic("%s: Unable to create kmem cache for hugeptes\n",
849                       __func__);
850 
851         /* Default hpage size = 4M */
852         if (mmu_psize_defs[MMU_PAGE_4M].shift)
853                 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_4M].shift;
854         else
855                 panic("%s: Unable to set default huge page size\n", __func__);
856 
857 
858         return 0;
859 }
860 #else
861 static int __init hugetlbpage_init(void)
862 {
863         int psize;
864 
865         if (!mmu_has_feature(MMU_FTR_16M_PAGE))
866                 return -ENODEV;
867 
868         for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
869                 unsigned shift;
870                 unsigned pdshift;
871 
872                 if (!mmu_psize_defs[psize].shift)
873                         continue;
874 
875                 shift = mmu_psize_to_shift(psize);
876 
877                 if (add_huge_page_size(1ULL << shift) < 0)
878                         continue;
879 
880                 if (shift < PMD_SHIFT)
881                         pdshift = PMD_SHIFT;
882                 else if (shift < PUD_SHIFT)
883                         pdshift = PUD_SHIFT;
884                 else
885                         pdshift = PGDIR_SHIFT;
886 
887                 pgtable_cache_add(pdshift - shift, NULL);
888                 if (!PGT_CACHE(pdshift - shift))
889                         panic("hugetlbpage_init(): could not create "
890                               "pgtable cache for %d bit pagesize\n", shift);
891         }
892 
893         /* Set default large page size. Currently, we pick 16M or 1M
894          * depending on what is available
895          */
896         if (mmu_psize_defs[MMU_PAGE_16M].shift)
897                 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_16M].shift;
898         else if (mmu_psize_defs[MMU_PAGE_1M].shift)
899                 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_1M].shift;
900 
901         return 0;
902 }
903 #endif
904 module_init(hugetlbpage_init);
905 
906 void flush_dcache_icache_hugepage(struct page *page)
907 {
908         int i;
909         void *start;
910 
911         BUG_ON(!PageCompound(page));
912 
913         for (i = 0; i < (1UL << compound_order(page)); i++) {
914                 if (!PageHighMem(page)) {
915                         __flush_dcache_icache(page_address(page+i));
916                 } else {
917                         start = kmap_atomic(page+i);
918                         __flush_dcache_icache(start);
919                         kunmap_atomic(start);
920                 }
921         }
922 }
923 

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