2 * PPC64 (POWER4) Huge TLB Page Support for Kernel.
4 * Copyright (C) 2003 David Gibson, IBM Corporation.
6 * Based on the IA-32 version:
7 * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
12 #include <linux/slab.h>
13 #include <linux/hugetlb.h>
14 #include <asm/pgtable.h>
15 #include <asm/pgalloc.h>
18 #define PAGE_SHIFT_64K 16
19 #define PAGE_SHIFT_16M 24
20 #define PAGE_SHIFT_16G 34
22 #define MAX_NUMBER_GPAGES 1024
24 /* Tracks the 16G pages after the device tree is scanned and before the
25 * huge_boot_pages list is ready. */
26 static unsigned long gpage_freearray[MAX_NUMBER_GPAGES];
27 static unsigned nr_gpages;
29 /* Flag to mark huge PD pointers. This means pmd_bad() and pud_bad()
30 * will choke on pointers to hugepte tables, which is handy for
31 * catching screwups early. */
33 static inline int shift_to_mmu_psize(unsigned int shift)
37 for (psize = 0; psize < MMU_PAGE_COUNT; ++psize)
38 if (mmu_psize_defs[psize].shift == shift)
43 static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
45 if (mmu_psize_defs[mmu_psize].shift)
46 return mmu_psize_defs[mmu_psize].shift;
50 #define hugepd_none(hpd) ((hpd).pd == 0)
52 static inline pte_t *hugepd_page(hugepd_t hpd)
54 BUG_ON(!hugepd_ok(hpd));
55 return (pte_t *)((hpd.pd & ~HUGEPD_SHIFT_MASK) | 0xc000000000000000);
58 static inline unsigned int hugepd_shift(hugepd_t hpd)
60 return hpd.pd & HUGEPD_SHIFT_MASK;
63 static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr, unsigned pdshift)
65 unsigned long idx = (addr & ((1UL << pdshift) - 1)) >> hugepd_shift(*hpdp);
66 pte_t *dir = hugepd_page(*hpdp);
71 pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift)
76 hugepd_t *hpdp = NULL;
77 unsigned pdshift = PGDIR_SHIFT;
82 pg = pgdir + pgd_index(ea);
84 hpdp = (hugepd_t *)pg;
85 } else if (!pgd_none(*pg)) {
87 pu = pud_offset(pg, ea);
89 hpdp = (hugepd_t *)pu;
90 else if (!pud_none(*pu)) {
92 pm = pmd_offset(pu, ea);
94 hpdp = (hugepd_t *)pm;
95 else if (!pmd_none(*pm)) {
96 return pte_offset_map(pm, ea);
105 *shift = hugepd_shift(*hpdp);
106 return hugepte_offset(hpdp, ea, pdshift);
109 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
111 return find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
114 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
115 unsigned long address, unsigned pdshift, unsigned pshift)
117 pte_t *new = kmem_cache_zalloc(PGT_CACHE(pdshift - pshift),
118 GFP_KERNEL|__GFP_REPEAT);
120 BUG_ON(pshift > HUGEPD_SHIFT_MASK);
121 BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);
126 spin_lock(&mm->page_table_lock);
127 if (!hugepd_none(*hpdp))
128 kmem_cache_free(PGT_CACHE(pdshift - pshift), new);
130 hpdp->pd = ((unsigned long)new & ~0x8000000000000000) | pshift;
131 spin_unlock(&mm->page_table_lock);
135 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
140 hugepd_t *hpdp = NULL;
141 unsigned pshift = __ffs(sz);
142 unsigned pdshift = PGDIR_SHIFT;
146 pg = pgd_offset(mm, addr);
147 if (pshift >= PUD_SHIFT) {
148 hpdp = (hugepd_t *)pg;
151 pu = pud_alloc(mm, pg, addr);
152 if (pshift >= PMD_SHIFT) {
153 hpdp = (hugepd_t *)pu;
156 pm = pmd_alloc(mm, pu, addr);
157 hpdp = (hugepd_t *)pm;
164 BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
166 if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift))
169 return hugepte_offset(hpdp, addr, pdshift);
172 /* Build list of addresses of gigantic pages. This function is used in early
173 * boot before the buddy or bootmem allocator is setup.
175 void add_gpage(unsigned long addr, unsigned long page_size,
176 unsigned long number_of_pages)
180 while (number_of_pages > 0) {
181 gpage_freearray[nr_gpages] = addr;
188 /* Moves the gigantic page addresses from the temporary list to the
189 * huge_boot_pages list.
191 int alloc_bootmem_huge_page(struct hstate *hstate)
193 struct huge_bootmem_page *m;
196 m = phys_to_virt(gpage_freearray[--nr_gpages]);
197 gpage_freearray[nr_gpages] = 0;
198 list_add(&m->list, &huge_boot_pages);
203 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
208 static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift,
209 unsigned long start, unsigned long end,
210 unsigned long floor, unsigned long ceiling)
212 pte_t *hugepte = hugepd_page(*hpdp);
213 unsigned shift = hugepd_shift(*hpdp);
214 unsigned long pdmask = ~((1UL << pdshift) - 1);
224 if (end - 1 > ceiling - 1)
229 pgtable_free_tlb(tlb, hugepte, pdshift - shift);
232 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
233 unsigned long addr, unsigned long end,
234 unsigned long floor, unsigned long ceiling)
241 pmd = pmd_offset(pud, addr);
243 next = pmd_addr_end(addr, end);
246 free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
247 addr, next, floor, ceiling);
248 } while (pmd++, addr = next, addr != end);
258 if (end - 1 > ceiling - 1)
261 pmd = pmd_offset(pud, start);
263 pmd_free_tlb(tlb, pmd, start);
266 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
267 unsigned long addr, unsigned long end,
268 unsigned long floor, unsigned long ceiling)
275 pud = pud_offset(pgd, addr);
277 next = pud_addr_end(addr, end);
278 if (!is_hugepd(pud)) {
279 if (pud_none_or_clear_bad(pud))
281 hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
284 free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
285 addr, next, floor, ceiling);
287 } while (pud++, addr = next, addr != end);
293 ceiling &= PGDIR_MASK;
297 if (end - 1 > ceiling - 1)
300 pud = pud_offset(pgd, start);
302 pud_free_tlb(tlb, pud, start);
306 * This function frees user-level page tables of a process.
308 * Must be called with pagetable lock held.
310 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
311 unsigned long addr, unsigned long end,
312 unsigned long floor, unsigned long ceiling)
318 * Because there are a number of different possible pagetable
319 * layouts for hugepage ranges, we limit knowledge of how
320 * things should be laid out to the allocation path
321 * (huge_pte_alloc(), above). Everything else works out the
322 * structure as it goes from information in the hugepd
323 * pointers. That means that we can't here use the
324 * optimization used in the normal page free_pgd_range(), of
325 * checking whether we're actually covering a large enough
326 * range to have to do anything at the top level of the walk
327 * instead of at the bottom.
329 * To make sense of this, you should probably go read the big
330 * block comment at the top of the normal free_pgd_range(),
334 pgd = pgd_offset(tlb->mm, addr);
336 next = pgd_addr_end(addr, end);
337 if (!is_hugepd(pgd)) {
338 if (pgd_none_or_clear_bad(pgd))
340 hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
342 free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT,
343 addr, next, floor, ceiling);
345 } while (pgd++, addr = next, addr != end);
349 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
356 ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift);
358 /* Verify it is a huge page else bail. */
360 return ERR_PTR(-EINVAL);
362 mask = (1UL << shift) - 1;
363 page = pte_page(*ptep);
365 page += (address & mask) / PAGE_SIZE;
370 int pmd_huge(pmd_t pmd)
375 int pud_huge(pud_t pud)
381 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
382 pmd_t *pmd, int write)
388 static noinline int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
389 unsigned long end, int write, struct page **pages, int *nr)
392 unsigned long pte_end;
393 struct page *head, *page;
397 pte_end = (addr + sz) & ~(sz-1);
402 mask = _PAGE_PRESENT | _PAGE_USER;
406 if ((pte_val(pte) & mask) != mask)
409 /* hugepages are never "special" */
410 VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
413 head = pte_page(pte);
415 page = head + ((addr & (sz-1)) >> PAGE_SHIFT);
417 VM_BUG_ON(compound_head(page) != head);
422 } while (addr += PAGE_SIZE, addr != end);
424 if (!page_cache_add_speculative(head, refs)) {
429 if (unlikely(pte_val(pte) != pte_val(*ptep))) {
430 /* Could be optimized better */
440 static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
443 unsigned long __boundary = (addr + sz) & ~(sz-1);
444 return (__boundary - 1 < end - 1) ? __boundary : end;
447 int gup_hugepd(hugepd_t *hugepd, unsigned pdshift,
448 unsigned long addr, unsigned long end,
449 int write, struct page **pages, int *nr)
452 unsigned long sz = 1UL << hugepd_shift(*hugepd);
455 ptep = hugepte_offset(hugepd, addr, pdshift);
457 next = hugepte_addr_end(addr, end, sz);
458 if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr))
460 } while (ptep++, addr = next, addr != end);
465 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
466 unsigned long len, unsigned long pgoff,
469 struct hstate *hstate = hstate_file(file);
470 int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
472 return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1, 0);
475 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
477 unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
479 return 1UL << mmu_psize_to_shift(psize);
482 static int __init add_huge_page_size(unsigned long long size)
484 int shift = __ffs(size);
487 /* Check that it is a page size supported by the hardware and
488 * that it fits within pagetable and slice limits. */
489 if (!is_power_of_2(size)
490 || (shift > SLICE_HIGH_SHIFT) || (shift <= PAGE_SHIFT))
493 if ((mmu_psize = shift_to_mmu_psize(shift)) < 0)
496 #ifdef CONFIG_SPU_FS_64K_LS
497 /* Disable support for 64K huge pages when 64K SPU local store
498 * support is enabled as the current implementation conflicts.
500 if (shift == PAGE_SHIFT_64K)
502 #endif /* CONFIG_SPU_FS_64K_LS */
504 BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
506 /* Return if huge page size has already been setup */
507 if (size_to_hstate(size))
510 hugetlb_add_hstate(shift - PAGE_SHIFT);
515 static int __init hugepage_setup_sz(char *str)
517 unsigned long long size;
519 size = memparse(str, &str);
521 if (add_huge_page_size(size) != 0)
522 printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size);
526 __setup("hugepagesz=", hugepage_setup_sz);
528 static int __init hugetlbpage_init(void)
532 if (!cpu_has_feature(CPU_FTR_16M_PAGE))
535 for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
539 if (!mmu_psize_defs[psize].shift)
542 shift = mmu_psize_to_shift(psize);
544 if (add_huge_page_size(1ULL << shift) < 0)
547 if (shift < PMD_SHIFT)
549 else if (shift < PUD_SHIFT)
552 pdshift = PGDIR_SHIFT;
554 pgtable_cache_add(pdshift - shift, NULL);
555 if (!PGT_CACHE(pdshift - shift))
556 panic("hugetlbpage_init(): could not create "
557 "pgtable cache for %d bit pagesize\n", shift);
560 /* Set default large page size. Currently, we pick 16M or 1M
561 * depending on what is available
563 if (mmu_psize_defs[MMU_PAGE_16M].shift)
564 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_16M].shift;
565 else if (mmu_psize_defs[MMU_PAGE_1M].shift)
566 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_1M].shift;
571 module_init(hugetlbpage_init);
573 void flush_dcache_icache_hugepage(struct page *page)
577 BUG_ON(!PageCompound(page));
579 for (i = 0; i < (1UL << compound_order(page)); i++)
580 __flush_dcache_icache(page_address(page+i));