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