SL*B: drop kmem cache argument from constructor
[linux-2.6.git] / 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_cache(psize)       (pgtable_cache[HUGEPTE_CACHE_NUM \
57                                                         + psize-1])
58 #define HUGEPTE_CACHE_NAME(psize)       (huge_pgtable_cache_name[psize])
59
60 static const char *huge_pgtable_cache_name[MMU_PAGE_COUNT] = {
61         "unused_4K", "hugepte_cache_64K", "unused_64K_AP",
62         "hugepte_cache_1M", "hugepte_cache_16M", "hugepte_cache_16G"
63 };
64
65 /* Flag to mark huge PD pointers.  This means pmd_bad() and pud_bad()
66  * will choke on pointers to hugepte tables, which is handy for
67  * catching screwups early. */
68 #define HUGEPD_OK       0x1
69
70 typedef struct { unsigned long pd; } hugepd_t;
71
72 #define hugepd_none(hpd)        ((hpd).pd == 0)
73
74 static inline int shift_to_mmu_psize(unsigned int shift)
75 {
76         switch (shift) {
77 #ifndef CONFIG_PPC_64K_PAGES
78         case PAGE_SHIFT_64K:
79             return MMU_PAGE_64K;
80 #endif
81         case PAGE_SHIFT_16M:
82             return MMU_PAGE_16M;
83         case PAGE_SHIFT_16G:
84             return MMU_PAGE_16G;
85         }
86         return -1;
87 }
88
89 static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
90 {
91         if (mmu_psize_defs[mmu_psize].shift)
92                 return mmu_psize_defs[mmu_psize].shift;
93         BUG();
94 }
95
96 static inline pte_t *hugepd_page(hugepd_t hpd)
97 {
98         BUG_ON(!(hpd.pd & HUGEPD_OK));
99         return (pte_t *)(hpd.pd & ~HUGEPD_OK);
100 }
101
102 static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr,
103                                     struct hstate *hstate)
104 {
105         unsigned int shift = huge_page_shift(hstate);
106         int psize = shift_to_mmu_psize(shift);
107         unsigned long idx = ((addr >> shift) & (PTRS_PER_HUGEPTE(psize)-1));
108         pte_t *dir = hugepd_page(*hpdp);
109
110         return dir + idx;
111 }
112
113 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
114                            unsigned long address, unsigned int psize)
115 {
116         pte_t *new = kmem_cache_zalloc(huge_pgtable_cache(psize),
117                                       GFP_KERNEL|__GFP_REPEAT);
118
119         if (! new)
120                 return -ENOMEM;
121
122         spin_lock(&mm->page_table_lock);
123         if (!hugepd_none(*hpdp))
124                 kmem_cache_free(huge_pgtable_cache(psize), new);
125         else
126                 hpdp->pd = (unsigned long)new | HUGEPD_OK;
127         spin_unlock(&mm->page_table_lock);
128         return 0;
129 }
130
131 /* Base page size affects how we walk hugetlb page tables */
132 #ifdef CONFIG_PPC_64K_PAGES
133 #define hpmd_offset(pud, addr, h)       pmd_offset(pud, addr)
134 #define hpmd_alloc(mm, pud, addr, h)    pmd_alloc(mm, pud, addr)
135 #else
136 static inline
137 pmd_t *hpmd_offset(pud_t *pud, unsigned long addr, struct hstate *hstate)
138 {
139         if (huge_page_shift(hstate) == PAGE_SHIFT_64K)
140                 return pmd_offset(pud, addr);
141         else
142                 return (pmd_t *) pud;
143 }
144 static inline
145 pmd_t *hpmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long addr,
146                   struct hstate *hstate)
147 {
148         if (huge_page_shift(hstate) == PAGE_SHIFT_64K)
149                 return pmd_alloc(mm, pud, addr);
150         else
151                 return (pmd_t *) pud;
152 }
153 #endif
154
155 /* Build list of addresses of gigantic pages.  This function is used in early
156  * boot before the buddy or bootmem allocator is setup.
157  */
158 void add_gpage(unsigned long addr, unsigned long page_size,
159         unsigned long number_of_pages)
160 {
161         if (!addr)
162                 return;
163         while (number_of_pages > 0) {
164                 gpage_freearray[nr_gpages] = addr;
165                 nr_gpages++;
166                 number_of_pages--;
167                 addr += page_size;
168         }
169 }
170
171 /* Moves the gigantic page addresses from the temporary list to the
172  * huge_boot_pages list.
173  */
174 int alloc_bootmem_huge_page(struct hstate *hstate)
175 {
176         struct huge_bootmem_page *m;
177         if (nr_gpages == 0)
178                 return 0;
179         m = phys_to_virt(gpage_freearray[--nr_gpages]);
180         gpage_freearray[nr_gpages] = 0;
181         list_add(&m->list, &huge_boot_pages);
182         m->hstate = hstate;
183         return 1;
184 }
185
186
187 /* Modelled after find_linux_pte() */
188 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
189 {
190         pgd_t *pg;
191         pud_t *pu;
192         pmd_t *pm;
193
194         unsigned int psize;
195         unsigned int shift;
196         unsigned long sz;
197         struct hstate *hstate;
198         psize = get_slice_psize(mm, addr);
199         shift = mmu_psize_to_shift(psize);
200         sz = ((1UL) << shift);
201         hstate = size_to_hstate(sz);
202
203         addr &= hstate->mask;
204
205         pg = pgd_offset(mm, addr);
206         if (!pgd_none(*pg)) {
207                 pu = pud_offset(pg, addr);
208                 if (!pud_none(*pu)) {
209                         pm = hpmd_offset(pu, addr, hstate);
210                         if (!pmd_none(*pm))
211                                 return hugepte_offset((hugepd_t *)pm, addr,
212                                                       hstate);
213                 }
214         }
215
216         return NULL;
217 }
218
219 pte_t *huge_pte_alloc(struct mm_struct *mm,
220                         unsigned long addr, unsigned long sz)
221 {
222         pgd_t *pg;
223         pud_t *pu;
224         pmd_t *pm;
225         hugepd_t *hpdp = NULL;
226         struct hstate *hstate;
227         unsigned int psize;
228         hstate = size_to_hstate(sz);
229
230         psize = get_slice_psize(mm, addr);
231         BUG_ON(!mmu_huge_psizes[psize]);
232
233         addr &= hstate->mask;
234
235         pg = pgd_offset(mm, addr);
236         pu = pud_alloc(mm, pg, addr);
237
238         if (pu) {
239                 pm = hpmd_alloc(mm, pu, addr, hstate);
240                 if (pm)
241                         hpdp = (hugepd_t *)pm;
242         }
243
244         if (! hpdp)
245                 return NULL;
246
247         if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, psize))
248                 return NULL;
249
250         return hugepte_offset(hpdp, addr, hstate);
251 }
252
253 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
254 {
255         return 0;
256 }
257
258 static void free_hugepte_range(struct mmu_gather *tlb, hugepd_t *hpdp,
259                                unsigned int psize)
260 {
261         pte_t *hugepte = hugepd_page(*hpdp);
262
263         hpdp->pd = 0;
264         tlb->need_flush = 1;
265         pgtable_free_tlb(tlb, pgtable_free_cache(hugepte,
266                                                  HUGEPTE_CACHE_NUM+psize-1,
267                                                  PGF_CACHENUM_MASK));
268 }
269
270 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
271                                    unsigned long addr, unsigned long end,
272                                    unsigned long floor, unsigned long ceiling,
273                                    unsigned int psize)
274 {
275         pmd_t *pmd;
276         unsigned long next;
277         unsigned long start;
278
279         start = addr;
280         pmd = pmd_offset(pud, addr);
281         do {
282                 next = pmd_addr_end(addr, end);
283                 if (pmd_none(*pmd))
284                         continue;
285                 free_hugepte_range(tlb, (hugepd_t *)pmd, psize);
286         } while (pmd++, addr = next, addr != end);
287
288         start &= PUD_MASK;
289         if (start < floor)
290                 return;
291         if (ceiling) {
292                 ceiling &= PUD_MASK;
293                 if (!ceiling)
294                         return;
295         }
296         if (end - 1 > ceiling - 1)
297                 return;
298
299         pmd = pmd_offset(pud, start);
300         pud_clear(pud);
301         pmd_free_tlb(tlb, pmd);
302 }
303
304 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
305                                    unsigned long addr, unsigned long end,
306                                    unsigned long floor, unsigned long ceiling)
307 {
308         pud_t *pud;
309         unsigned long next;
310         unsigned long start;
311         unsigned int shift;
312         unsigned int psize = get_slice_psize(tlb->mm, addr);
313         shift = mmu_psize_to_shift(psize);
314
315         start = addr;
316         pud = pud_offset(pgd, addr);
317         do {
318                 next = pud_addr_end(addr, end);
319 #ifdef CONFIG_PPC_64K_PAGES
320                 if (pud_none_or_clear_bad(pud))
321                         continue;
322                 hugetlb_free_pmd_range(tlb, pud, addr, next, floor, ceiling,
323                                        psize);
324 #else
325                 if (shift == PAGE_SHIFT_64K) {
326                         if (pud_none_or_clear_bad(pud))
327                                 continue;
328                         hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
329                                                ceiling, psize);
330                 } else {
331                         if (pud_none(*pud))
332                                 continue;
333                         free_hugepte_range(tlb, (hugepd_t *)pud, psize);
334                 }
335 #endif
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 (pgd_none_or_clear_bad(pgd))
426                         continue;
427                 hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
428         } while (pgd++, addr = next, addr != end);
429 }
430
431 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
432                      pte_t *ptep, pte_t pte)
433 {
434         if (pte_present(*ptep)) {
435                 /* We open-code pte_clear because we need to pass the right
436                  * argument to hpte_need_flush (huge / !huge). Might not be
437                  * necessary anymore if we make hpte_need_flush() get the
438                  * page size from the slices
439                  */
440                 unsigned int psize = get_slice_psize(mm, addr);
441                 unsigned int shift = mmu_psize_to_shift(psize);
442                 unsigned long sz = ((1UL) << shift);
443                 struct hstate *hstate = size_to_hstate(sz);
444                 pte_update(mm, addr & hstate->mask, ptep, ~0UL, 1);
445         }
446         *ptep = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
447 }
448
449 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
450                               pte_t *ptep)
451 {
452         unsigned long old = pte_update(mm, addr, ptep, ~0UL, 1);
453         return __pte(old);
454 }
455
456 struct page *
457 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
458 {
459         pte_t *ptep;
460         struct page *page;
461         unsigned int mmu_psize = get_slice_psize(mm, address);
462
463         /* Verify it is a huge page else bail. */
464         if (!mmu_huge_psizes[mmu_psize])
465                 return ERR_PTR(-EINVAL);
466
467         ptep = huge_pte_offset(mm, address);
468         page = pte_page(*ptep);
469         if (page) {
470                 unsigned int shift = mmu_psize_to_shift(mmu_psize);
471                 unsigned long sz = ((1UL) << shift);
472                 page += (address % sz) / PAGE_SIZE;
473         }
474
475         return page;
476 }
477
478 int pmd_huge(pmd_t pmd)
479 {
480         return 0;
481 }
482
483 int pud_huge(pud_t pud)
484 {
485         return 0;
486 }
487
488 struct page *
489 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
490                 pmd_t *pmd, int write)
491 {
492         BUG();
493         return NULL;
494 }
495
496
497 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
498                                         unsigned long len, unsigned long pgoff,
499                                         unsigned long flags)
500 {
501         struct hstate *hstate = hstate_file(file);
502         int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
503         return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1, 0);
504 }
505
506 /*
507  * Called by asm hashtable.S for doing lazy icache flush
508  */
509 static unsigned int hash_huge_page_do_lazy_icache(unsigned long rflags,
510                                         pte_t pte, int trap, unsigned long sz)
511 {
512         struct page *page;
513         int i;
514
515         if (!pfn_valid(pte_pfn(pte)))
516                 return rflags;
517
518         page = pte_page(pte);
519
520         /* page is dirty */
521         if (!test_bit(PG_arch_1, &page->flags) && !PageReserved(page)) {
522                 if (trap == 0x400) {
523                         for (i = 0; i < (sz / PAGE_SIZE); i++)
524                                 __flush_dcache_icache(page_address(page+i));
525                         set_bit(PG_arch_1, &page->flags);
526                 } else {
527                         rflags |= HPTE_R_N;
528                 }
529         }
530         return rflags;
531 }
532
533 int hash_huge_page(struct mm_struct *mm, unsigned long access,
534                    unsigned long ea, unsigned long vsid, int local,
535                    unsigned long trap)
536 {
537         pte_t *ptep;
538         unsigned long old_pte, new_pte;
539         unsigned long va, rflags, pa, sz;
540         long slot;
541         int err = 1;
542         int ssize = user_segment_size(ea);
543         unsigned int mmu_psize;
544         int shift;
545         mmu_psize = get_slice_psize(mm, ea);
546
547         if (!mmu_huge_psizes[mmu_psize])
548                 goto out;
549         ptep = huge_pte_offset(mm, ea);
550
551         /* Search the Linux page table for a match with va */
552         va = hpt_va(ea, vsid, ssize);
553
554         /*
555          * If no pte found or not present, send the problem up to
556          * do_page_fault
557          */
558         if (unlikely(!ptep || pte_none(*ptep)))
559                 goto out;
560
561         /* 
562          * Check the user's access rights to the page.  If access should be
563          * prevented then send the problem up to do_page_fault.
564          */
565         if (unlikely(access & ~pte_val(*ptep)))
566                 goto out;
567         /*
568          * At this point, we have a pte (old_pte) which can be used to build
569          * or update an HPTE. There are 2 cases:
570          *
571          * 1. There is a valid (present) pte with no associated HPTE (this is 
572          *      the most common case)
573          * 2. There is a valid (present) pte with an associated HPTE. The
574          *      current values of the pp bits in the HPTE prevent access
575          *      because we are doing software DIRTY bit management and the
576          *      page is currently not DIRTY. 
577          */
578
579
580         do {
581                 old_pte = pte_val(*ptep);
582                 if (old_pte & _PAGE_BUSY)
583                         goto out;
584                 new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
585         } while(old_pte != __cmpxchg_u64((unsigned long *)ptep,
586                                          old_pte, new_pte));
587
588         rflags = 0x2 | (!(new_pte & _PAGE_RW));
589         /* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */
590         rflags |= ((new_pte & _PAGE_EXEC) ? 0 : HPTE_R_N);
591         shift = mmu_psize_to_shift(mmu_psize);
592         sz = ((1UL) << shift);
593         if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
594                 /* No CPU has hugepages but lacks no execute, so we
595                  * don't need to worry about that case */
596                 rflags = hash_huge_page_do_lazy_icache(rflags, __pte(old_pte),
597                                                        trap, sz);
598
599         /* Check if pte already has an hpte (case 2) */
600         if (unlikely(old_pte & _PAGE_HASHPTE)) {
601                 /* There MIGHT be an HPTE for this pte */
602                 unsigned long hash, slot;
603
604                 hash = hpt_hash(va, shift, ssize);
605                 if (old_pte & _PAGE_F_SECOND)
606                         hash = ~hash;
607                 slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
608                 slot += (old_pte & _PAGE_F_GIX) >> 12;
609
610                 if (ppc_md.hpte_updatepp(slot, rflags, va, mmu_psize,
611                                          ssize, local) == -1)
612                         old_pte &= ~_PAGE_HPTEFLAGS;
613         }
614
615         if (likely(!(old_pte & _PAGE_HASHPTE))) {
616                 unsigned long hash = hpt_hash(va, shift, ssize);
617                 unsigned long hpte_group;
618
619                 pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
620
621 repeat:
622                 hpte_group = ((hash & htab_hash_mask) *
623                               HPTES_PER_GROUP) & ~0x7UL;
624
625                 /* clear HPTE slot informations in new PTE */
626 #ifdef CONFIG_PPC_64K_PAGES
627                 new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HPTE_SUB0;
628 #else
629                 new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
630 #endif
631                 /* Add in WIMG bits */
632                 rflags |= (new_pte & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
633                                       _PAGE_COHERENT | _PAGE_GUARDED));
634
635                 /* Insert into the hash table, primary slot */
636                 slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags, 0,
637                                           mmu_psize, ssize);
638
639                 /* Primary is full, try the secondary */
640                 if (unlikely(slot == -1)) {
641                         hpte_group = ((~hash & htab_hash_mask) *
642                                       HPTES_PER_GROUP) & ~0x7UL; 
643                         slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags,
644                                                   HPTE_V_SECONDARY,
645                                                   mmu_psize, ssize);
646                         if (slot == -1) {
647                                 if (mftb() & 0x1)
648                                         hpte_group = ((hash & htab_hash_mask) *
649                                                       HPTES_PER_GROUP)&~0x7UL;
650
651                                 ppc_md.hpte_remove(hpte_group);
652                                 goto repeat;
653                         }
654                 }
655
656                 if (unlikely(slot == -2))
657                         panic("hash_huge_page: pte_insert failed\n");
658
659                 new_pte |= (slot << 12) & (_PAGE_F_SECOND | _PAGE_F_GIX);
660         }
661
662         /*
663          * No need to use ldarx/stdcx here
664          */
665         *ptep = __pte(new_pte & ~_PAGE_BUSY);
666
667         err = 0;
668
669  out:
670         return err;
671 }
672
673 void set_huge_psize(int psize)
674 {
675         /* Check that it is a page size supported by the hardware and
676          * that it fits within pagetable limits. */
677         if (mmu_psize_defs[psize].shift &&
678                 mmu_psize_defs[psize].shift < SID_SHIFT_1T &&
679                 (mmu_psize_defs[psize].shift > MIN_HUGEPTE_SHIFT ||
680                  mmu_psize_defs[psize].shift == PAGE_SHIFT_64K ||
681                  mmu_psize_defs[psize].shift == PAGE_SHIFT_16G)) {
682                 /* Return if huge page size has already been setup or is the
683                  * same as the base page size. */
684                 if (mmu_huge_psizes[psize] ||
685                    mmu_psize_defs[psize].shift == PAGE_SHIFT)
686                         return;
687                 hugetlb_add_hstate(mmu_psize_defs[psize].shift - PAGE_SHIFT);
688
689                 switch (mmu_psize_defs[psize].shift) {
690                 case PAGE_SHIFT_64K:
691                     /* We only allow 64k hpages with 4k base page,
692                      * which was checked above, and always put them
693                      * at the PMD */
694                     hugepte_shift[psize] = PMD_SHIFT;
695                     break;
696                 case PAGE_SHIFT_16M:
697                     /* 16M pages can be at two different levels
698                      * of pagestables based on base page size */
699                     if (PAGE_SHIFT == PAGE_SHIFT_64K)
700                             hugepte_shift[psize] = PMD_SHIFT;
701                     else /* 4k base page */
702                             hugepte_shift[psize] = PUD_SHIFT;
703                     break;
704                 case PAGE_SHIFT_16G:
705                     /* 16G pages are always at PGD level */
706                     hugepte_shift[psize] = PGDIR_SHIFT;
707                     break;
708                 }
709                 hugepte_shift[psize] -= mmu_psize_defs[psize].shift;
710         } else
711                 hugepte_shift[psize] = 0;
712 }
713
714 static int __init hugepage_setup_sz(char *str)
715 {
716         unsigned long long size;
717         int mmu_psize;
718         int shift;
719
720         size = memparse(str, &str);
721
722         shift = __ffs(size);
723         mmu_psize = shift_to_mmu_psize(shift);
724         if (mmu_psize >= 0 && mmu_psize_defs[mmu_psize].shift)
725                 set_huge_psize(mmu_psize);
726         else
727                 printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size);
728
729         return 1;
730 }
731 __setup("hugepagesz=", hugepage_setup_sz);
732
733 static int __init hugetlbpage_init(void)
734 {
735         unsigned int psize;
736
737         if (!cpu_has_feature(CPU_FTR_16M_PAGE))
738                 return -ENODEV;
739         /* Add supported huge page sizes.  Need to change HUGE_MAX_HSTATE
740          * and adjust PTE_NONCACHE_NUM if the number of supported huge page
741          * sizes changes.
742          */
743         set_huge_psize(MMU_PAGE_16M);
744         set_huge_psize(MMU_PAGE_64K);
745         set_huge_psize(MMU_PAGE_16G);
746
747         for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
748                 if (mmu_huge_psizes[psize]) {
749                         huge_pgtable_cache(psize) = kmem_cache_create(
750                                                 HUGEPTE_CACHE_NAME(psize),
751                                                 HUGEPTE_TABLE_SIZE(psize),
752                                                 HUGEPTE_TABLE_SIZE(psize),
753                                                 0,
754                                                 NULL);
755                         if (!huge_pgtable_cache(psize))
756                                 panic("hugetlbpage_init(): could not create %s"\
757                                       "\n", HUGEPTE_CACHE_NAME(psize));
758                 }
759         }
760
761         return 0;
762 }
763
764 module_init(hugetlbpage_init);