Merge branch 'topic/jack' into for-linus
[linux-2.6] / arch / powerpc / mm / hugetlbpage.c
1 /*
2  * PPC64 (POWER4) Huge TLB Page Support for Kernel.
3  *
4  * Copyright (C) 2003 David Gibson, IBM Corporation.
5  *
6  * Based on the IA-32 version:
7  * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
8  */
9
10 #include <linux/init.h>
11 #include <linux/fs.h>
12 #include <linux/mm.h>
13 #include <linux/hugetlb.h>
14 #include <linux/pagemap.h>
15 #include <linux/slab.h>
16 #include <linux/err.h>
17 #include <linux/sysctl.h>
18 #include <asm/mman.h>
19 #include <asm/pgalloc.h>
20 #include <asm/tlb.h>
21 #include <asm/tlbflush.h>
22 #include <asm/mmu_context.h>
23 #include <asm/machdep.h>
24 #include <asm/cputable.h>
25 #include <asm/spu.h>
26
27 #define PAGE_SHIFT_64K  16
28 #define PAGE_SHIFT_16M  24
29 #define PAGE_SHIFT_16G  34
30
31 #define NUM_LOW_AREAS   (0x100000000UL >> SID_SHIFT)
32 #define NUM_HIGH_AREAS  (PGTABLE_RANGE >> HTLB_AREA_SHIFT)
33 #define MAX_NUMBER_GPAGES       1024
34
35 /* Tracks the 16G pages after the device tree is scanned and before the
36  * huge_boot_pages list is ready.  */
37 static unsigned long gpage_freearray[MAX_NUMBER_GPAGES];
38 static unsigned nr_gpages;
39
40 /* Array of valid huge page sizes - non-zero value(hugepte_shift) is
41  * stored for the huge page sizes that are valid.
42  */
43 unsigned int mmu_huge_psizes[MMU_PAGE_COUNT] = { }; /* initialize all to 0 */
44
45 #define hugepte_shift                   mmu_huge_psizes
46 #define PTRS_PER_HUGEPTE(psize)         (1 << hugepte_shift[psize])
47 #define HUGEPTE_TABLE_SIZE(psize)       (sizeof(pte_t) << hugepte_shift[psize])
48
49 #define HUGEPD_SHIFT(psize)             (mmu_psize_to_shift(psize) \
50                                                 + hugepte_shift[psize])
51 #define HUGEPD_SIZE(psize)              (1UL << HUGEPD_SHIFT(psize))
52 #define HUGEPD_MASK(psize)              (~(HUGEPD_SIZE(psize)-1))
53
54 /* Subtract one from array size because we don't need a cache for 4K since
55  * is not a huge page size */
56 #define HUGE_PGTABLE_INDEX(psize)       (HUGEPTE_CACHE_NUM + psize - 1)
57 #define HUGEPTE_CACHE_NAME(psize)       (huge_pgtable_cache_name[psize])
58
59 static const char *huge_pgtable_cache_name[MMU_PAGE_COUNT] = {
60         "unused_4K", "hugepte_cache_64K", "unused_64K_AP",
61         "hugepte_cache_1M", "hugepte_cache_16M", "hugepte_cache_16G"
62 };
63
64 /* Flag to mark huge PD pointers.  This means pmd_bad() and pud_bad()
65  * will choke on pointers to hugepte tables, which is handy for
66  * catching screwups early. */
67 #define HUGEPD_OK       0x1
68
69 typedef struct { unsigned long pd; } hugepd_t;
70
71 #define hugepd_none(hpd)        ((hpd).pd == 0)
72
73 static inline int shift_to_mmu_psize(unsigned int shift)
74 {
75         switch (shift) {
76 #ifndef CONFIG_PPC_64K_PAGES
77         case PAGE_SHIFT_64K:
78             return MMU_PAGE_64K;
79 #endif
80         case PAGE_SHIFT_16M:
81             return MMU_PAGE_16M;
82         case PAGE_SHIFT_16G:
83             return MMU_PAGE_16G;
84         }
85         return -1;
86 }
87
88 static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
89 {
90         if (mmu_psize_defs[mmu_psize].shift)
91                 return mmu_psize_defs[mmu_psize].shift;
92         BUG();
93 }
94
95 static inline pte_t *hugepd_page(hugepd_t hpd)
96 {
97         BUG_ON(!(hpd.pd & HUGEPD_OK));
98         return (pte_t *)(hpd.pd & ~HUGEPD_OK);
99 }
100
101 static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr,
102                                     struct hstate *hstate)
103 {
104         unsigned int shift = huge_page_shift(hstate);
105         int psize = shift_to_mmu_psize(shift);
106         unsigned long idx = ((addr >> shift) & (PTRS_PER_HUGEPTE(psize)-1));
107         pte_t *dir = hugepd_page(*hpdp);
108
109         return dir + idx;
110 }
111
112 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
113                            unsigned long address, unsigned int psize)
114 {
115         pte_t *new = kmem_cache_zalloc(pgtable_cache[HUGE_PGTABLE_INDEX(psize)],
116                                       GFP_KERNEL|__GFP_REPEAT);
117
118         if (! new)
119                 return -ENOMEM;
120
121         spin_lock(&mm->page_table_lock);
122         if (!hugepd_none(*hpdp))
123                 kmem_cache_free(pgtable_cache[HUGE_PGTABLE_INDEX(psize)], new);
124         else
125                 hpdp->pd = (unsigned long)new | HUGEPD_OK;
126         spin_unlock(&mm->page_table_lock);
127         return 0;
128 }
129
130
131 static pud_t *hpud_offset(pgd_t *pgd, unsigned long addr, struct hstate *hstate)
132 {
133         if (huge_page_shift(hstate) < PUD_SHIFT)
134                 return pud_offset(pgd, addr);
135         else
136                 return (pud_t *) pgd;
137 }
138 static pud_t *hpud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long addr,
139                          struct hstate *hstate)
140 {
141         if (huge_page_shift(hstate) < PUD_SHIFT)
142                 return pud_alloc(mm, pgd, addr);
143         else
144                 return (pud_t *) pgd;
145 }
146 static pmd_t *hpmd_offset(pud_t *pud, unsigned long addr, struct hstate *hstate)
147 {
148         if (huge_page_shift(hstate) < PMD_SHIFT)
149                 return pmd_offset(pud, addr);
150         else
151                 return (pmd_t *) pud;
152 }
153 static pmd_t *hpmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long addr,
154                          struct hstate *hstate)
155 {
156         if (huge_page_shift(hstate) < PMD_SHIFT)
157                 return pmd_alloc(mm, pud, addr);
158         else
159                 return (pmd_t *) pud;
160 }
161
162 /* Build list of addresses of gigantic pages.  This function is used in early
163  * boot before the buddy or bootmem allocator is setup.
164  */
165 void add_gpage(unsigned long addr, unsigned long page_size,
166         unsigned long number_of_pages)
167 {
168         if (!addr)
169                 return;
170         while (number_of_pages > 0) {
171                 gpage_freearray[nr_gpages] = addr;
172                 nr_gpages++;
173                 number_of_pages--;
174                 addr += page_size;
175         }
176 }
177
178 /* Moves the gigantic page addresses from the temporary list to the
179  * huge_boot_pages list.
180  */
181 int alloc_bootmem_huge_page(struct hstate *hstate)
182 {
183         struct huge_bootmem_page *m;
184         if (nr_gpages == 0)
185                 return 0;
186         m = phys_to_virt(gpage_freearray[--nr_gpages]);
187         gpage_freearray[nr_gpages] = 0;
188         list_add(&m->list, &huge_boot_pages);
189         m->hstate = hstate;
190         return 1;
191 }
192
193
194 /* Modelled after find_linux_pte() */
195 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
196 {
197         pgd_t *pg;
198         pud_t *pu;
199         pmd_t *pm;
200
201         unsigned int psize;
202         unsigned int shift;
203         unsigned long sz;
204         struct hstate *hstate;
205         psize = get_slice_psize(mm, addr);
206         shift = mmu_psize_to_shift(psize);
207         sz = ((1UL) << shift);
208         hstate = size_to_hstate(sz);
209
210         addr &= hstate->mask;
211
212         pg = pgd_offset(mm, addr);
213         if (!pgd_none(*pg)) {
214                 pu = hpud_offset(pg, addr, hstate);
215                 if (!pud_none(*pu)) {
216                         pm = hpmd_offset(pu, addr, hstate);
217                         if (!pmd_none(*pm))
218                                 return hugepte_offset((hugepd_t *)pm, addr,
219                                                       hstate);
220                 }
221         }
222
223         return NULL;
224 }
225
226 pte_t *huge_pte_alloc(struct mm_struct *mm,
227                         unsigned long addr, unsigned long sz)
228 {
229         pgd_t *pg;
230         pud_t *pu;
231         pmd_t *pm;
232         hugepd_t *hpdp = NULL;
233         struct hstate *hstate;
234         unsigned int psize;
235         hstate = size_to_hstate(sz);
236
237         psize = get_slice_psize(mm, addr);
238         BUG_ON(!mmu_huge_psizes[psize]);
239
240         addr &= hstate->mask;
241
242         pg = pgd_offset(mm, addr);
243         pu = hpud_alloc(mm, pg, addr, hstate);
244
245         if (pu) {
246                 pm = hpmd_alloc(mm, pu, addr, hstate);
247                 if (pm)
248                         hpdp = (hugepd_t *)pm;
249         }
250
251         if (! hpdp)
252                 return NULL;
253
254         if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, psize))
255                 return NULL;
256
257         return hugepte_offset(hpdp, addr, hstate);
258 }
259
260 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
261 {
262         return 0;
263 }
264
265 static void free_hugepte_range(struct mmu_gather *tlb, hugepd_t *hpdp,
266                                unsigned int psize)
267 {
268         pte_t *hugepte = hugepd_page(*hpdp);
269
270         hpdp->pd = 0;
271         tlb->need_flush = 1;
272         pgtable_free_tlb(tlb, pgtable_free_cache(hugepte,
273                                                  HUGEPTE_CACHE_NUM+psize-1,
274                                                  PGF_CACHENUM_MASK));
275 }
276
277 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
278                                    unsigned long addr, unsigned long end,
279                                    unsigned long floor, unsigned long ceiling,
280                                    unsigned int psize)
281 {
282         pmd_t *pmd;
283         unsigned long next;
284         unsigned long start;
285
286         start = addr;
287         pmd = pmd_offset(pud, addr);
288         do {
289                 next = pmd_addr_end(addr, end);
290                 if (pmd_none(*pmd))
291                         continue;
292                 free_hugepte_range(tlb, (hugepd_t *)pmd, psize);
293         } while (pmd++, addr = next, addr != end);
294
295         start &= PUD_MASK;
296         if (start < floor)
297                 return;
298         if (ceiling) {
299                 ceiling &= PUD_MASK;
300                 if (!ceiling)
301                         return;
302         }
303         if (end - 1 > ceiling - 1)
304                 return;
305
306         pmd = pmd_offset(pud, start);
307         pud_clear(pud);
308         pmd_free_tlb(tlb, pmd);
309 }
310
311 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
312                                    unsigned long addr, unsigned long end,
313                                    unsigned long floor, unsigned long ceiling)
314 {
315         pud_t *pud;
316         unsigned long next;
317         unsigned long start;
318         unsigned int shift;
319         unsigned int psize = get_slice_psize(tlb->mm, addr);
320         shift = mmu_psize_to_shift(psize);
321
322         start = addr;
323         pud = pud_offset(pgd, addr);
324         do {
325                 next = pud_addr_end(addr, end);
326                 if (shift < PMD_SHIFT) {
327                         if (pud_none_or_clear_bad(pud))
328                                 continue;
329                         hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
330                                                ceiling, psize);
331                 } else {
332                         if (pud_none(*pud))
333                                 continue;
334                         free_hugepte_range(tlb, (hugepd_t *)pud, psize);
335                 }
336         } while (pud++, addr = next, addr != end);
337
338         start &= PGDIR_MASK;
339         if (start < floor)
340                 return;
341         if (ceiling) {
342                 ceiling &= PGDIR_MASK;
343                 if (!ceiling)
344                         return;
345         }
346         if (end - 1 > ceiling - 1)
347                 return;
348
349         pud = pud_offset(pgd, start);
350         pgd_clear(pgd);
351         pud_free_tlb(tlb, pud);
352 }
353
354 /*
355  * This function frees user-level page tables of a process.
356  *
357  * Must be called with pagetable lock held.
358  */
359 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
360                             unsigned long addr, unsigned long end,
361                             unsigned long floor, unsigned long ceiling)
362 {
363         pgd_t *pgd;
364         unsigned long next;
365         unsigned long start;
366
367         /*
368          * Comments below take from the normal free_pgd_range().  They
369          * apply here too.  The tests against HUGEPD_MASK below are
370          * essential, because we *don't* test for this at the bottom
371          * level.  Without them we'll attempt to free a hugepte table
372          * when we unmap just part of it, even if there are other
373          * active mappings using it.
374          *
375          * The next few lines have given us lots of grief...
376          *
377          * Why are we testing HUGEPD* at this top level?  Because
378          * often there will be no work to do at all, and we'd prefer
379          * not to go all the way down to the bottom just to discover
380          * that.
381          *
382          * Why all these "- 1"s?  Because 0 represents both the bottom
383          * of the address space and the top of it (using -1 for the
384          * top wouldn't help much: the masks would do the wrong thing).
385          * The rule is that addr 0 and floor 0 refer to the bottom of
386          * the address space, but end 0 and ceiling 0 refer to the top
387          * Comparisons need to use "end - 1" and "ceiling - 1" (though
388          * that end 0 case should be mythical).
389          *
390          * Wherever addr is brought up or ceiling brought down, we
391          * must be careful to reject "the opposite 0" before it
392          * confuses the subsequent tests.  But what about where end is
393          * brought down by HUGEPD_SIZE below? no, end can't go down to
394          * 0 there.
395          *
396          * Whereas we round start (addr) and ceiling down, by different
397          * masks at different levels, in order to test whether a table
398          * now has no other vmas using it, so can be freed, we don't
399          * bother to round floor or end up - the tests don't need that.
400          */
401         unsigned int psize = get_slice_psize(tlb->mm, addr);
402
403         addr &= HUGEPD_MASK(psize);
404         if (addr < floor) {
405                 addr += HUGEPD_SIZE(psize);
406                 if (!addr)
407                         return;
408         }
409         if (ceiling) {
410                 ceiling &= HUGEPD_MASK(psize);
411                 if (!ceiling)
412                         return;
413         }
414         if (end - 1 > ceiling - 1)
415                 end -= HUGEPD_SIZE(psize);
416         if (addr > end - 1)
417                 return;
418
419         start = addr;
420         pgd = pgd_offset(tlb->mm, addr);
421         do {
422                 psize = get_slice_psize(tlb->mm, addr);
423                 BUG_ON(!mmu_huge_psizes[psize]);
424                 next = pgd_addr_end(addr, end);
425                 if (mmu_psize_to_shift(psize) < PUD_SHIFT) {
426                         if (pgd_none_or_clear_bad(pgd))
427                                 continue;
428                         hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
429                 } else {
430                         if (pgd_none(*pgd))
431                                 continue;
432                         free_hugepte_range(tlb, (hugepd_t *)pgd, psize);
433                 }
434         } while (pgd++, addr = next, addr != end);
435 }
436
437 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
438                      pte_t *ptep, pte_t pte)
439 {
440         if (pte_present(*ptep)) {
441                 /* We open-code pte_clear because we need to pass the right
442                  * argument to hpte_need_flush (huge / !huge). Might not be
443                  * necessary anymore if we make hpte_need_flush() get the
444                  * page size from the slices
445                  */
446                 unsigned int psize = get_slice_psize(mm, addr);
447                 unsigned int shift = mmu_psize_to_shift(psize);
448                 unsigned long sz = ((1UL) << shift);
449                 struct hstate *hstate = size_to_hstate(sz);
450                 pte_update(mm, addr & hstate->mask, ptep, ~0UL, 1);
451         }
452         *ptep = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
453 }
454
455 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
456                               pte_t *ptep)
457 {
458         unsigned long old = pte_update(mm, addr, ptep, ~0UL, 1);
459         return __pte(old);
460 }
461
462 struct page *
463 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
464 {
465         pte_t *ptep;
466         struct page *page;
467         unsigned int mmu_psize = get_slice_psize(mm, address);
468
469         /* Verify it is a huge page else bail. */
470         if (!mmu_huge_psizes[mmu_psize])
471                 return ERR_PTR(-EINVAL);
472
473         ptep = huge_pte_offset(mm, address);
474         page = pte_page(*ptep);
475         if (page) {
476                 unsigned int shift = mmu_psize_to_shift(mmu_psize);
477                 unsigned long sz = ((1UL) << shift);
478                 page += (address % sz) / PAGE_SIZE;
479         }
480
481         return page;
482 }
483
484 int pmd_huge(pmd_t pmd)
485 {
486         return 0;
487 }
488
489 int pud_huge(pud_t pud)
490 {
491         return 0;
492 }
493
494 struct page *
495 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
496                 pmd_t *pmd, int write)
497 {
498         BUG();
499         return NULL;
500 }
501
502
503 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
504                                         unsigned long len, unsigned long pgoff,
505                                         unsigned long flags)
506 {
507         struct hstate *hstate = hstate_file(file);
508         int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
509
510         if (!mmu_huge_psizes[mmu_psize])
511                 return -EINVAL;
512         return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1, 0);
513 }
514
515 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
516 {
517         unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
518
519         return 1UL << mmu_psize_to_shift(psize);
520 }
521
522 /*
523  * Called by asm hashtable.S for doing lazy icache flush
524  */
525 static unsigned int hash_huge_page_do_lazy_icache(unsigned long rflags,
526                                         pte_t pte, int trap, unsigned long sz)
527 {
528         struct page *page;
529         int i;
530
531         if (!pfn_valid(pte_pfn(pte)))
532                 return rflags;
533
534         page = pte_page(pte);
535
536         /* page is dirty */
537         if (!test_bit(PG_arch_1, &page->flags) && !PageReserved(page)) {
538                 if (trap == 0x400) {
539                         for (i = 0; i < (sz / PAGE_SIZE); i++)
540                                 __flush_dcache_icache(page_address(page+i));
541                         set_bit(PG_arch_1, &page->flags);
542                 } else {
543                         rflags |= HPTE_R_N;
544                 }
545         }
546         return rflags;
547 }
548
549 int hash_huge_page(struct mm_struct *mm, unsigned long access,
550                    unsigned long ea, unsigned long vsid, int local,
551                    unsigned long trap)
552 {
553         pte_t *ptep;
554         unsigned long old_pte, new_pte;
555         unsigned long va, rflags, pa, sz;
556         long slot;
557         int err = 1;
558         int ssize = user_segment_size(ea);
559         unsigned int mmu_psize;
560         int shift;
561         mmu_psize = get_slice_psize(mm, ea);
562
563         if (!mmu_huge_psizes[mmu_psize])
564                 goto out;
565         ptep = huge_pte_offset(mm, ea);
566
567         /* Search the Linux page table for a match with va */
568         va = hpt_va(ea, vsid, ssize);
569
570         /*
571          * If no pte found or not present, send the problem up to
572          * do_page_fault
573          */
574         if (unlikely(!ptep || pte_none(*ptep)))
575                 goto out;
576
577         /* 
578          * Check the user's access rights to the page.  If access should be
579          * prevented then send the problem up to do_page_fault.
580          */
581         if (unlikely(access & ~pte_val(*ptep)))
582                 goto out;
583         /*
584          * At this point, we have a pte (old_pte) which can be used to build
585          * or update an HPTE. There are 2 cases:
586          *
587          * 1. There is a valid (present) pte with no associated HPTE (this is 
588          *      the most common case)
589          * 2. There is a valid (present) pte with an associated HPTE. The
590          *      current values of the pp bits in the HPTE prevent access
591          *      because we are doing software DIRTY bit management and the
592          *      page is currently not DIRTY. 
593          */
594
595
596         do {
597                 old_pte = pte_val(*ptep);
598                 if (old_pte & _PAGE_BUSY)
599                         goto out;
600                 new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
601         } while(old_pte != __cmpxchg_u64((unsigned long *)ptep,
602                                          old_pte, new_pte));
603
604         rflags = 0x2 | (!(new_pte & _PAGE_RW));
605         /* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */
606         rflags |= ((new_pte & _PAGE_EXEC) ? 0 : HPTE_R_N);
607         shift = mmu_psize_to_shift(mmu_psize);
608         sz = ((1UL) << shift);
609         if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
610                 /* No CPU has hugepages but lacks no execute, so we
611                  * don't need to worry about that case */
612                 rflags = hash_huge_page_do_lazy_icache(rflags, __pte(old_pte),
613                                                        trap, sz);
614
615         /* Check if pte already has an hpte (case 2) */
616         if (unlikely(old_pte & _PAGE_HASHPTE)) {
617                 /* There MIGHT be an HPTE for this pte */
618                 unsigned long hash, slot;
619
620                 hash = hpt_hash(va, shift, ssize);
621                 if (old_pte & _PAGE_F_SECOND)
622                         hash = ~hash;
623                 slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
624                 slot += (old_pte & _PAGE_F_GIX) >> 12;
625
626                 if (ppc_md.hpte_updatepp(slot, rflags, va, mmu_psize,
627                                          ssize, local) == -1)
628                         old_pte &= ~_PAGE_HPTEFLAGS;
629         }
630
631         if (likely(!(old_pte & _PAGE_HASHPTE))) {
632                 unsigned long hash = hpt_hash(va, shift, ssize);
633                 unsigned long hpte_group;
634
635                 pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
636
637 repeat:
638                 hpte_group = ((hash & htab_hash_mask) *
639                               HPTES_PER_GROUP) & ~0x7UL;
640
641                 /* clear HPTE slot informations in new PTE */
642 #ifdef CONFIG_PPC_64K_PAGES
643                 new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HPTE_SUB0;
644 #else
645                 new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
646 #endif
647                 /* Add in WIMG bits */
648                 rflags |= (new_pte & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
649                                       _PAGE_COHERENT | _PAGE_GUARDED));
650
651                 /* Insert into the hash table, primary slot */
652                 slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags, 0,
653                                           mmu_psize, ssize);
654
655                 /* Primary is full, try the secondary */
656                 if (unlikely(slot == -1)) {
657                         hpte_group = ((~hash & htab_hash_mask) *
658                                       HPTES_PER_GROUP) & ~0x7UL; 
659                         slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags,
660                                                   HPTE_V_SECONDARY,
661                                                   mmu_psize, ssize);
662                         if (slot == -1) {
663                                 if (mftb() & 0x1)
664                                         hpte_group = ((hash & htab_hash_mask) *
665                                                       HPTES_PER_GROUP)&~0x7UL;
666
667                                 ppc_md.hpte_remove(hpte_group);
668                                 goto repeat;
669                         }
670                 }
671
672                 if (unlikely(slot == -2))
673                         panic("hash_huge_page: pte_insert failed\n");
674
675                 new_pte |= (slot << 12) & (_PAGE_F_SECOND | _PAGE_F_GIX);
676         }
677
678         /*
679          * No need to use ldarx/stdcx here
680          */
681         *ptep = __pte(new_pte & ~_PAGE_BUSY);
682
683         err = 0;
684
685  out:
686         return err;
687 }
688
689 static void __init set_huge_psize(int psize)
690 {
691         /* Check that it is a page size supported by the hardware and
692          * that it fits within pagetable limits. */
693         if (mmu_psize_defs[psize].shift &&
694                 mmu_psize_defs[psize].shift < SID_SHIFT_1T &&
695                 (mmu_psize_defs[psize].shift > MIN_HUGEPTE_SHIFT ||
696                  mmu_psize_defs[psize].shift == PAGE_SHIFT_64K ||
697                  mmu_psize_defs[psize].shift == PAGE_SHIFT_16G)) {
698                 /* Return if huge page size has already been setup or is the
699                  * same as the base page size. */
700                 if (mmu_huge_psizes[psize] ||
701                    mmu_psize_defs[psize].shift == PAGE_SHIFT)
702                         return;
703                 hugetlb_add_hstate(mmu_psize_defs[psize].shift - PAGE_SHIFT);
704
705                 switch (mmu_psize_defs[psize].shift) {
706                 case PAGE_SHIFT_64K:
707                     /* We only allow 64k hpages with 4k base page,
708                      * which was checked above, and always put them
709                      * at the PMD */
710                     hugepte_shift[psize] = PMD_SHIFT;
711                     break;
712                 case PAGE_SHIFT_16M:
713                     /* 16M pages can be at two different levels
714                      * of pagestables based on base page size */
715                     if (PAGE_SHIFT == PAGE_SHIFT_64K)
716                             hugepte_shift[psize] = PMD_SHIFT;
717                     else /* 4k base page */
718                             hugepte_shift[psize] = PUD_SHIFT;
719                     break;
720                 case PAGE_SHIFT_16G:
721                     /* 16G pages are always at PGD level */
722                     hugepte_shift[psize] = PGDIR_SHIFT;
723                     break;
724                 }
725                 hugepte_shift[psize] -= mmu_psize_defs[psize].shift;
726         } else
727                 hugepte_shift[psize] = 0;
728 }
729
730 static int __init hugepage_setup_sz(char *str)
731 {
732         unsigned long long size;
733         int mmu_psize;
734         int shift;
735
736         size = memparse(str, &str);
737
738         shift = __ffs(size);
739         mmu_psize = shift_to_mmu_psize(shift);
740         if (mmu_psize >= 0 && mmu_psize_defs[mmu_psize].shift)
741                 set_huge_psize(mmu_psize);
742         else
743                 printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size);
744
745         return 1;
746 }
747 __setup("hugepagesz=", hugepage_setup_sz);
748
749 static int __init hugetlbpage_init(void)
750 {
751         unsigned int psize;
752
753         if (!cpu_has_feature(CPU_FTR_16M_PAGE))
754                 return -ENODEV;
755
756         /* Add supported huge page sizes.  Need to change HUGE_MAX_HSTATE
757          * and adjust PTE_NONCACHE_NUM if the number of supported huge page
758          * sizes changes.
759          */
760         set_huge_psize(MMU_PAGE_16M);
761         set_huge_psize(MMU_PAGE_16G);
762
763         /* Temporarily disable support for 64K huge pages when 64K SPU local
764          * store support is enabled as the current implementation conflicts.
765          */
766 #ifndef CONFIG_SPU_FS_64K_LS
767         set_huge_psize(MMU_PAGE_64K);
768 #endif
769
770         for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
771                 if (mmu_huge_psizes[psize]) {
772                         pgtable_cache[HUGE_PGTABLE_INDEX(psize)] =
773                                 kmem_cache_create(
774                                         HUGEPTE_CACHE_NAME(psize),
775                                         HUGEPTE_TABLE_SIZE(psize),
776                                         HUGEPTE_TABLE_SIZE(psize),
777                                         0,
778                                         NULL);
779                         if (!pgtable_cache[HUGE_PGTABLE_INDEX(psize)])
780                                 panic("hugetlbpage_init(): could not create %s"\
781                                       "\n", HUGEPTE_CACHE_NAME(psize));
782                 }
783         }
784
785         return 0;
786 }
787
788 module_init(hugetlbpage_init);