2 * PPC Huge TLB Page Support for Kernel.
4 * Copyright (C) 2003 David Gibson, IBM Corporation.
5 * Copyright (C) 2011 Becky Bruce, Freescale Semiconductor
7 * Based on the IA-32 version:
8 * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
13 #include <linux/slab.h>
14 #include <linux/hugetlb.h>
15 #include <linux/export.h>
16 #include <linux/of_fdt.h>
17 #include <linux/memblock.h>
18 #include <linux/bootmem.h>
19 #include <linux/moduleparam.h>
20 #include <asm/pgtable.h>
21 #include <asm/pgalloc.h>
23 #include <asm/setup.h>
24 #include <asm/hugetlb.h>
26 #ifdef CONFIG_HUGETLB_PAGE
28 #define PAGE_SHIFT_64K 16
29 #define PAGE_SHIFT_16M 24
30 #define PAGE_SHIFT_16G 34
32 unsigned int HPAGE_SHIFT;
35 * Tracks gpages after the device tree is scanned and before the
36 * huge_boot_pages list is ready. On non-Freescale implementations, this is
37 * just used to track 16G pages and so is a single array. FSL-based
38 * implementations may have more than one gpage size, so we need multiple
41 #ifdef CONFIG_PPC_FSL_BOOK3E
42 #define MAX_NUMBER_GPAGES 128
44 u64 gpage_list[MAX_NUMBER_GPAGES];
45 unsigned int nr_gpages;
47 static struct psize_gpages gpage_freearray[MMU_PAGE_COUNT];
49 #define MAX_NUMBER_GPAGES 1024
50 static u64 gpage_freearray[MAX_NUMBER_GPAGES];
51 static unsigned nr_gpages;
54 #define hugepd_none(hpd) ((hpd).pd == 0)
56 #ifdef CONFIG_PPC_BOOK3S_64
58 * At this point we do the placement change only for BOOK3S 64. This would
59 * possibly work on other subarchs.
63 * We have PGD_INDEX_SIZ = 12 and PTE_INDEX_SIZE = 8, so that we can have
64 * 16GB hugepage pte in PGD and 16MB hugepage pte at PMD;
66 * Defined in such a way that we can optimize away code block at build time
67 * if CONFIG_HUGETLB_PAGE=n.
69 int pmd_huge(pmd_t pmd)
72 * leaf pte for huge page, bottom two bits != 00
74 return ((pmd_val(pmd) & 0x3) != 0x0);
77 int pud_huge(pud_t pud)
80 * leaf pte for huge page, bottom two bits != 00
82 return ((pud_val(pud) & 0x3) != 0x0);
85 int pgd_huge(pgd_t pgd)
88 * leaf pte for huge page, bottom two bits != 00
90 return ((pgd_val(pgd) & 0x3) != 0x0);
93 int pmd_huge(pmd_t pmd)
98 int pud_huge(pud_t pud)
103 int pgd_huge(pgd_t pgd)
109 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
111 /* Only called for hugetlbfs pages, hence can ignore THP */
112 return __find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
115 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
116 unsigned long address, unsigned pdshift, unsigned pshift)
118 struct kmem_cache *cachep;
121 #ifdef CONFIG_PPC_FSL_BOOK3E
123 int num_hugepd = 1 << (pshift - pdshift);
124 cachep = hugepte_cache;
126 cachep = PGT_CACHE(pdshift - pshift);
129 new = kmem_cache_zalloc(cachep, GFP_KERNEL|__GFP_REPEAT);
131 BUG_ON(pshift > HUGEPD_SHIFT_MASK);
132 BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);
137 spin_lock(&mm->page_table_lock);
138 #ifdef CONFIG_PPC_FSL_BOOK3E
140 * We have multiple higher-level entries that point to the same
141 * actual pte location. Fill in each as we go and backtrack on error.
142 * We need all of these so the DTLB pgtable walk code can find the
143 * right higher-level entry without knowing if it's a hugepage or not.
145 for (i = 0; i < num_hugepd; i++, hpdp++) {
146 if (unlikely(!hugepd_none(*hpdp)))
149 /* We use the old format for PPC_FSL_BOOK3E */
150 hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift;
152 /* If we bailed from the for loop early, an error occurred, clean up */
153 if (i < num_hugepd) {
154 for (i = i - 1 ; i >= 0; i--, hpdp--)
156 kmem_cache_free(cachep, new);
159 if (!hugepd_none(*hpdp))
160 kmem_cache_free(cachep, new);
162 #ifdef CONFIG_PPC_BOOK3S_64
163 hpdp->pd = (unsigned long)new |
164 (shift_to_mmu_psize(pshift) << 2);
166 hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift;
170 spin_unlock(&mm->page_table_lock);
175 * These macros define how to determine which level of the page table holds
178 #ifdef CONFIG_PPC_FSL_BOOK3E
179 #define HUGEPD_PGD_SHIFT PGDIR_SHIFT
180 #define HUGEPD_PUD_SHIFT PUD_SHIFT
182 #define HUGEPD_PGD_SHIFT PUD_SHIFT
183 #define HUGEPD_PUD_SHIFT PMD_SHIFT
186 #ifdef CONFIG_PPC_BOOK3S_64
188 * At this point we do the placement change only for BOOK3S 64. This would
189 * possibly work on other subarchs.
191 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
196 hugepd_t *hpdp = NULL;
197 unsigned pshift = __ffs(sz);
198 unsigned pdshift = PGDIR_SHIFT;
201 pg = pgd_offset(mm, addr);
203 if (pshift == PGDIR_SHIFT)
206 else if (pshift > PUD_SHIFT)
208 * We need to use hugepd table
210 hpdp = (hugepd_t *)pg;
213 pu = pud_alloc(mm, pg, addr);
214 if (pshift == PUD_SHIFT)
216 else if (pshift > PMD_SHIFT)
217 hpdp = (hugepd_t *)pu;
220 pm = pmd_alloc(mm, pu, addr);
221 if (pshift == PMD_SHIFT)
225 hpdp = (hugepd_t *)pm;
231 BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
233 if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift))
236 return hugepte_offset(*hpdp, addr, pdshift);
241 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
246 hugepd_t *hpdp = NULL;
247 unsigned pshift = __ffs(sz);
248 unsigned pdshift = PGDIR_SHIFT;
252 pg = pgd_offset(mm, addr);
254 if (pshift >= HUGEPD_PGD_SHIFT) {
255 hpdp = (hugepd_t *)pg;
258 pu = pud_alloc(mm, pg, addr);
259 if (pshift >= HUGEPD_PUD_SHIFT) {
260 hpdp = (hugepd_t *)pu;
263 pm = pmd_alloc(mm, pu, addr);
264 hpdp = (hugepd_t *)pm;
271 BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
273 if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift))
276 return hugepte_offset(*hpdp, addr, pdshift);
280 #ifdef CONFIG_PPC_FSL_BOOK3E
281 /* Build list of addresses of gigantic pages. This function is used in early
282 * boot before the buddy allocator is setup.
284 void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
286 unsigned int idx = shift_to_mmu_psize(__ffs(page_size));
292 gpage_freearray[idx].nr_gpages = number_of_pages;
294 for (i = 0; i < number_of_pages; i++) {
295 gpage_freearray[idx].gpage_list[i] = addr;
301 * Moves the gigantic page addresses from the temporary list to the
302 * huge_boot_pages list.
304 int alloc_bootmem_huge_page(struct hstate *hstate)
306 struct huge_bootmem_page *m;
307 int idx = shift_to_mmu_psize(huge_page_shift(hstate));
308 int nr_gpages = gpage_freearray[idx].nr_gpages;
313 #ifdef CONFIG_HIGHMEM
315 * If gpages can be in highmem we can't use the trick of storing the
316 * data structure in the page; allocate space for this
318 m = memblock_virt_alloc(sizeof(struct huge_bootmem_page), 0);
319 m->phys = gpage_freearray[idx].gpage_list[--nr_gpages];
321 m = phys_to_virt(gpage_freearray[idx].gpage_list[--nr_gpages]);
324 list_add(&m->list, &huge_boot_pages);
325 gpage_freearray[idx].nr_gpages = nr_gpages;
326 gpage_freearray[idx].gpage_list[nr_gpages] = 0;
332 * Scan the command line hugepagesz= options for gigantic pages; store those in
333 * a list that we use to allocate the memory once all options are parsed.
336 unsigned long gpage_npages[MMU_PAGE_COUNT];
338 static int __init do_gpage_early_setup(char *param, char *val,
339 const char *unused, void *arg)
341 static phys_addr_t size;
342 unsigned long npages;
345 * The hugepagesz and hugepages cmdline options are interleaved. We
346 * use the size variable to keep track of whether or not this was done
347 * properly and skip over instances where it is incorrect. Other
348 * command-line parsing code will issue warnings, so we don't need to.
351 if ((strcmp(param, "default_hugepagesz") == 0) ||
352 (strcmp(param, "hugepagesz") == 0)) {
353 size = memparse(val, NULL);
354 } else if (strcmp(param, "hugepages") == 0) {
356 if (sscanf(val, "%lu", &npages) <= 0)
358 if (npages > MAX_NUMBER_GPAGES) {
359 pr_warn("MMU: %lu pages requested for page "
360 "size %llu KB, limiting to "
361 __stringify(MAX_NUMBER_GPAGES) "\n",
362 npages, size / 1024);
363 npages = MAX_NUMBER_GPAGES;
365 gpage_npages[shift_to_mmu_psize(__ffs(size))] = npages;
374 * This function allocates physical space for pages that are larger than the
375 * buddy allocator can handle. We want to allocate these in highmem because
376 * the amount of lowmem is limited. This means that this function MUST be
377 * called before lowmem_end_addr is set up in MMU_init() in order for the lmb
378 * allocate to grab highmem.
380 void __init reserve_hugetlb_gpages(void)
382 static __initdata char cmdline[COMMAND_LINE_SIZE];
383 phys_addr_t size, base;
386 strlcpy(cmdline, boot_command_line, COMMAND_LINE_SIZE);
387 parse_args("hugetlb gpages", cmdline, NULL, 0, 0, 0,
388 NULL, &do_gpage_early_setup);
391 * Walk gpage list in reverse, allocating larger page sizes first.
392 * Skip over unsupported sizes, or sizes that have 0 gpages allocated.
393 * When we reach the point in the list where pages are no longer
394 * considered gpages, we're done.
396 for (i = MMU_PAGE_COUNT-1; i >= 0; i--) {
397 if (mmu_psize_defs[i].shift == 0 || gpage_npages[i] == 0)
399 else if (mmu_psize_to_shift(i) < (MAX_ORDER + PAGE_SHIFT))
402 size = (phys_addr_t)(1ULL << mmu_psize_to_shift(i));
403 base = memblock_alloc_base(size * gpage_npages[i], size,
404 MEMBLOCK_ALLOC_ANYWHERE);
405 add_gpage(base, size, gpage_npages[i]);
409 #else /* !PPC_FSL_BOOK3E */
411 /* Build list of addresses of gigantic pages. This function is used in early
412 * boot before the buddy allocator is setup.
414 void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
418 while (number_of_pages > 0) {
419 gpage_freearray[nr_gpages] = addr;
426 /* Moves the gigantic page addresses from the temporary list to the
427 * huge_boot_pages list.
429 int alloc_bootmem_huge_page(struct hstate *hstate)
431 struct huge_bootmem_page *m;
434 m = phys_to_virt(gpage_freearray[--nr_gpages]);
435 gpage_freearray[nr_gpages] = 0;
436 list_add(&m->list, &huge_boot_pages);
442 #ifdef CONFIG_PPC_FSL_BOOK3E
443 #define HUGEPD_FREELIST_SIZE \
444 ((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))
446 struct hugepd_freelist {
452 static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur);
454 static void hugepd_free_rcu_callback(struct rcu_head *head)
456 struct hugepd_freelist *batch =
457 container_of(head, struct hugepd_freelist, rcu);
460 for (i = 0; i < batch->index; i++)
461 kmem_cache_free(hugepte_cache, batch->ptes[i]);
463 free_page((unsigned long)batch);
466 static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
468 struct hugepd_freelist **batchp;
470 batchp = this_cpu_ptr(&hugepd_freelist_cur);
472 if (atomic_read(&tlb->mm->mm_users) < 2 ||
473 cpumask_equal(mm_cpumask(tlb->mm),
474 cpumask_of(smp_processor_id()))) {
475 kmem_cache_free(hugepte_cache, hugepte);
476 put_cpu_var(hugepd_freelist_cur);
480 if (*batchp == NULL) {
481 *batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC);
482 (*batchp)->index = 0;
485 (*batchp)->ptes[(*batchp)->index++] = hugepte;
486 if ((*batchp)->index == HUGEPD_FREELIST_SIZE) {
487 call_rcu_sched(&(*batchp)->rcu, hugepd_free_rcu_callback);
490 put_cpu_var(hugepd_freelist_cur);
494 static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift,
495 unsigned long start, unsigned long end,
496 unsigned long floor, unsigned long ceiling)
498 pte_t *hugepte = hugepd_page(*hpdp);
501 unsigned long pdmask = ~((1UL << pdshift) - 1);
502 unsigned int num_hugepd = 1;
504 #ifdef CONFIG_PPC_FSL_BOOK3E
505 /* Note: On fsl the hpdp may be the first of several */
506 num_hugepd = (1 << (hugepd_shift(*hpdp) - pdshift));
508 unsigned int shift = hugepd_shift(*hpdp);
519 if (end - 1 > ceiling - 1)
522 for (i = 0; i < num_hugepd; i++, hpdp++)
525 #ifdef CONFIG_PPC_FSL_BOOK3E
526 hugepd_free(tlb, hugepte);
528 pgtable_free_tlb(tlb, hugepte, pdshift - shift);
532 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
533 unsigned long addr, unsigned long end,
534 unsigned long floor, unsigned long ceiling)
542 pmd = pmd_offset(pud, addr);
543 next = pmd_addr_end(addr, end);
544 if (!is_hugepd(__hugepd(pmd_val(*pmd)))) {
546 * if it is not hugepd pointer, we should already find
549 WARN_ON(!pmd_none_or_clear_bad(pmd));
552 #ifdef CONFIG_PPC_FSL_BOOK3E
554 * Increment next by the size of the huge mapping since
555 * there may be more than one entry at this level for a
556 * single hugepage, but all of them point to
557 * the same kmem cache that holds the hugepte.
559 next = addr + (1 << hugepd_shift(*(hugepd_t *)pmd));
561 free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
562 addr, next, floor, ceiling);
563 } while (addr = next, addr != end);
573 if (end - 1 > ceiling - 1)
576 pmd = pmd_offset(pud, start);
578 pmd_free_tlb(tlb, pmd, start);
579 mm_dec_nr_pmds(tlb->mm);
582 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
583 unsigned long addr, unsigned long end,
584 unsigned long floor, unsigned long ceiling)
592 pud = pud_offset(pgd, addr);
593 next = pud_addr_end(addr, end);
594 if (!is_hugepd(__hugepd(pud_val(*pud)))) {
595 if (pud_none_or_clear_bad(pud))
597 hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
600 #ifdef CONFIG_PPC_FSL_BOOK3E
602 * Increment next by the size of the huge mapping since
603 * there may be more than one entry at this level for a
604 * single hugepage, but all of them point to
605 * the same kmem cache that holds the hugepte.
607 next = addr + (1 << hugepd_shift(*(hugepd_t *)pud));
609 free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
610 addr, next, floor, ceiling);
612 } while (addr = next, addr != end);
618 ceiling &= PGDIR_MASK;
622 if (end - 1 > ceiling - 1)
625 pud = pud_offset(pgd, start);
627 pud_free_tlb(tlb, pud, start);
631 * This function frees user-level page tables of a process.
633 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
634 unsigned long addr, unsigned long end,
635 unsigned long floor, unsigned long ceiling)
641 * Because there are a number of different possible pagetable
642 * layouts for hugepage ranges, we limit knowledge of how
643 * things should be laid out to the allocation path
644 * (huge_pte_alloc(), above). Everything else works out the
645 * structure as it goes from information in the hugepd
646 * pointers. That means that we can't here use the
647 * optimization used in the normal page free_pgd_range(), of
648 * checking whether we're actually covering a large enough
649 * range to have to do anything at the top level of the walk
650 * instead of at the bottom.
652 * To make sense of this, you should probably go read the big
653 * block comment at the top of the normal free_pgd_range(),
658 next = pgd_addr_end(addr, end);
659 pgd = pgd_offset(tlb->mm, addr);
660 if (!is_hugepd(__hugepd(pgd_val(*pgd)))) {
661 if (pgd_none_or_clear_bad(pgd))
663 hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
665 #ifdef CONFIG_PPC_FSL_BOOK3E
667 * Increment next by the size of the huge mapping since
668 * there may be more than one entry at the pgd level
669 * for a single hugepage, but all of them point to the
670 * same kmem cache that holds the hugepte.
672 next = addr + (1 << hugepd_shift(*(hugepd_t *)pgd));
674 free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT,
675 addr, next, floor, ceiling);
677 } while (addr = next, addr != end);
681 * We are holding mmap_sem, so a parallel huge page collapse cannot run.
682 * To prevent hugepage split, disable irq.
685 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
689 unsigned long mask, flags;
690 struct page *page = ERR_PTR(-EINVAL);
692 local_irq_save(flags);
693 ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift);
696 pte = READ_ONCE(*ptep);
698 * Verify it is a huge page else bail.
699 * Transparent hugepages are handled by generic code. We can skip them
702 if (!shift || pmd_trans_huge(__pmd(pte_val(pte))))
705 if (!pte_present(pte)) {
709 mask = (1UL << shift) - 1;
710 page = pte_page(pte);
712 page += (address & mask) / PAGE_SIZE;
715 local_irq_restore(flags);
720 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
721 pmd_t *pmd, int write)
728 follow_huge_pud(struct mm_struct *mm, unsigned long address,
729 pud_t *pud, int write)
735 static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
738 unsigned long __boundary = (addr + sz) & ~(sz-1);
739 return (__boundary - 1 < end - 1) ? __boundary : end;
742 int gup_huge_pd(hugepd_t hugepd, unsigned long addr, unsigned pdshift,
743 unsigned long end, int write, struct page **pages, int *nr)
746 unsigned long sz = 1UL << hugepd_shift(hugepd);
749 ptep = hugepte_offset(hugepd, addr, pdshift);
751 next = hugepte_addr_end(addr, end, sz);
752 if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr))
754 } while (ptep++, addr = next, addr != end);
759 #ifdef CONFIG_PPC_MM_SLICES
760 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
761 unsigned long len, unsigned long pgoff,
764 struct hstate *hstate = hstate_file(file);
765 int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
767 return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1);
771 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
773 #ifdef CONFIG_PPC_MM_SLICES
774 unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
776 return 1UL << mmu_psize_to_shift(psize);
778 if (!is_vm_hugetlb_page(vma))
781 return huge_page_size(hstate_vma(vma));
785 static inline bool is_power_of_4(unsigned long x)
787 if (is_power_of_2(x))
788 return (__ilog2(x) % 2) ? false : true;
792 static int __init add_huge_page_size(unsigned long long size)
794 int shift = __ffs(size);
797 /* Check that it is a page size supported by the hardware and
798 * that it fits within pagetable and slice limits. */
799 #ifdef CONFIG_PPC_FSL_BOOK3E
800 if ((size < PAGE_SIZE) || !is_power_of_4(size))
803 if (!is_power_of_2(size)
804 || (shift > SLICE_HIGH_SHIFT) || (shift <= PAGE_SHIFT))
808 if ((mmu_psize = shift_to_mmu_psize(shift)) < 0)
811 BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
813 /* Return if huge page size has already been setup */
814 if (size_to_hstate(size))
817 hugetlb_add_hstate(shift - PAGE_SHIFT);
822 static int __init hugepage_setup_sz(char *str)
824 unsigned long long size;
826 size = memparse(str, &str);
828 if (add_huge_page_size(size) != 0)
829 printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size);
833 __setup("hugepagesz=", hugepage_setup_sz);
835 #ifdef CONFIG_PPC_FSL_BOOK3E
836 struct kmem_cache *hugepte_cache;
837 static int __init hugetlbpage_init(void)
841 for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
844 if (!mmu_psize_defs[psize].shift)
847 shift = mmu_psize_to_shift(psize);
849 /* Don't treat normal page sizes as huge... */
850 if (shift != PAGE_SHIFT)
851 if (add_huge_page_size(1ULL << shift) < 0)
856 * Create a kmem cache for hugeptes. The bottom bits in the pte have
857 * size information encoded in them, so align them to allow this
859 hugepte_cache = kmem_cache_create("hugepte-cache", sizeof(pte_t),
860 HUGEPD_SHIFT_MASK + 1, 0, NULL);
861 if (hugepte_cache == NULL)
862 panic("%s: Unable to create kmem cache for hugeptes\n",
865 /* Default hpage size = 4M */
866 if (mmu_psize_defs[MMU_PAGE_4M].shift)
867 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_4M].shift;
869 panic("%s: Unable to set default huge page size\n", __func__);
875 static int __init hugetlbpage_init(void)
879 if (!mmu_has_feature(MMU_FTR_16M_PAGE))
882 for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
886 if (!mmu_psize_defs[psize].shift)
889 shift = mmu_psize_to_shift(psize);
891 if (add_huge_page_size(1ULL << shift) < 0)
894 if (shift < PMD_SHIFT)
896 else if (shift < PUD_SHIFT)
899 pdshift = PGDIR_SHIFT;
901 * if we have pdshift and shift value same, we don't
902 * use pgt cache for hugepd.
904 if (pdshift != shift) {
905 pgtable_cache_add(pdshift - shift, NULL);
906 if (!PGT_CACHE(pdshift - shift))
907 panic("hugetlbpage_init(): could not create "
908 "pgtable cache for %d bit pagesize\n", shift);
912 /* Set default large page size. Currently, we pick 16M or 1M
913 * depending on what is available
915 if (mmu_psize_defs[MMU_PAGE_16M].shift)
916 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_16M].shift;
917 else if (mmu_psize_defs[MMU_PAGE_1M].shift)
918 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_1M].shift;
923 arch_initcall(hugetlbpage_init);
925 void flush_dcache_icache_hugepage(struct page *page)
930 BUG_ON(!PageCompound(page));
932 for (i = 0; i < (1UL << compound_order(page)); i++) {
933 if (!PageHighMem(page)) {
934 __flush_dcache_icache(page_address(page+i));
936 start = kmap_atomic(page+i);
937 __flush_dcache_icache(start);
938 kunmap_atomic(start);
943 #endif /* CONFIG_HUGETLB_PAGE */
946 * We have 4 cases for pgds and pmds:
947 * (1) invalid (all zeroes)
948 * (2) pointer to next table, as normal; bottom 6 bits == 0
949 * (3) leaf pte for huge page, bottom two bits != 00
950 * (4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table
952 * So long as we atomically load page table pointers we are safe against teardown,
953 * we can follow the address down to the the page and take a ref on it.
954 * This function need to be called with interrupts disabled. We use this variant
955 * when we have MSR[EE] = 0 but the paca->soft_enabled = 1
958 pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
965 hugepd_t *hpdp = NULL;
966 unsigned pdshift = PGDIR_SHIFT;
971 pgdp = pgdir + pgd_index(ea);
972 pgd = READ_ONCE(*pgdp);
974 * Always operate on the local stack value. This make sure the
975 * value don't get updated by a parallel THP split/collapse,
976 * page fault or a page unmap. The return pte_t * is still not
977 * stable. So should be checked there for above conditions.
981 else if (pgd_huge(pgd)) {
982 ret_pte = (pte_t *) pgdp;
984 } else if (is_hugepd(__hugepd(pgd_val(pgd))))
985 hpdp = (hugepd_t *)&pgd;
988 * Even if we end up with an unmap, the pgtable will not
989 * be freed, because we do an rcu free and here we are
993 pudp = pud_offset(&pgd, ea);
994 pud = READ_ONCE(*pudp);
998 else if (pud_huge(pud)) {
999 ret_pte = (pte_t *) pudp;
1001 } else if (is_hugepd(__hugepd(pud_val(pud))))
1002 hpdp = (hugepd_t *)&pud;
1004 pdshift = PMD_SHIFT;
1005 pmdp = pmd_offset(&pud, ea);
1006 pmd = READ_ONCE(*pmdp);
1008 * A hugepage collapse is captured by pmd_none, because
1009 * it mark the pmd none and do a hpte invalidate.
1011 * We don't worry about pmd_trans_splitting here, The
1012 * caller if it needs to handle the splitting case
1013 * should check for that.
1018 if (pmd_huge(pmd) || pmd_large(pmd)) {
1019 ret_pte = (pte_t *) pmdp;
1021 } else if (is_hugepd(__hugepd(pmd_val(pmd))))
1022 hpdp = (hugepd_t *)&pmd;
1024 return pte_offset_kernel(&pmd, ea);
1030 ret_pte = hugepte_offset(*hpdp, ea, pdshift);
1031 pdshift = hugepd_shift(*hpdp);
1037 EXPORT_SYMBOL_GPL(__find_linux_pte_or_hugepte);
1039 int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
1040 unsigned long end, int write, struct page **pages, int *nr)
1043 unsigned long pte_end;
1044 struct page *head, *page, *tail;
1048 pte_end = (addr + sz) & ~(sz-1);
1052 pte = READ_ONCE(*ptep);
1053 mask = _PAGE_PRESENT | _PAGE_USER;
1057 if ((pte_val(pte) & mask) != mask)
1060 /* hugepages are never "special" */
1061 VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
1064 head = pte_page(pte);
1066 page = head + ((addr & (sz-1)) >> PAGE_SHIFT);
1069 VM_BUG_ON(compound_head(page) != head);
1074 } while (addr += PAGE_SIZE, addr != end);
1076 if (!page_cache_add_speculative(head, refs)) {
1081 if (unlikely(pte_val(pte) != pte_val(*ptep))) {
1082 /* Could be optimized better */
1090 * Any tail page need their mapcount reference taken before we
1095 get_huge_page_tail(tail);