arch/ia64/mm/hugetlbpage.c

   1 /*
   2  * IA-64 Huge TLB Page Support for Kernel.
   3  *
   4  * Copyright (C) 2002-2004 Rohit Seth <rohit.seth@intel.com>
   5  * Copyright (C) 2003-2004 Ken Chen <kenneth.w.chen@intel.com>
   6  *
   7  * Sep, 2003: add numa support
   8  * Feb, 2004: dynamic hugetlb page size via boot parameter
   9  */
  10
  11 #include <linux/config.h>
  12 #include <linux/init.h>
  13 #include <linux/fs.h>
  14 #include <linux/mm.h>
  15 #include <linux/hugetlb.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/smp_lock.h>
  18 #include <linux/slab.h>
  19 #include <linux/sysctl.h>
  20 #include <asm/mman.h>
  21 #include <asm/pgalloc.h>
  22 #include <asm/tlb.h>
  23 #include <asm/tlbflush.h>
  24
  25 unsigned int hpage_shift=HPAGE_SHIFT_DEFAULT;
  26
  27 static pte_t *
  28 huge_pte_alloc (struct mm_struct *mm, unsigned long addr)
  29 {
  30         unsigned long taddr = htlbpage_to_page(addr);
  31         pgd_t *pgd;
  32         pud_t *pud;
  33         pmd_t *pmd;
  34         pte_t *pte = NULL;
  35
  36         pgd = pgd_offset(mm, taddr);
  37         pud = pud_alloc(mm, pgd, taddr);
  38         if (pud) {
  39                 pmd = pmd_alloc(mm, pud, taddr);
  40                 if (pmd)
  41                         pte = pte_alloc_map(mm, pmd, taddr);
  42         }
  43         return pte;
  44 }
  45
  46 static pte_t *
  47 huge_pte_offset (struct mm_struct *mm, unsigned long addr)
  48 {
  49         unsigned long taddr = htlbpage_to_page(addr);
  50         pgd_t *pgd;
  51         pud_t *pud;
  52         pmd_t *pmd;
  53         pte_t *pte = NULL;
  54
  55         pgd = pgd_offset(mm, taddr);
  56         if (pgd_present(*pgd)) {
  57                 pud = pud_offset(pgd, taddr);
  58                 if (pud_present(*pud)) {
  59                         pmd = pmd_offset(pud, taddr);
  60                         if (pmd_present(*pmd))
  61                                 pte = pte_offset_map(pmd, taddr);
  62                 }
  63         }
  64
  65         return pte;
  66 }
  67
  68 #define mk_pte_huge(entry) { pte_val(entry) |= _PAGE_P; }
  69
  70 static void
  71 set_huge_pte (struct mm_struct *mm, struct vm_area_struct *vma,
  72               struct page *page, pte_t * page_table, int write_access)
  73 {
  74         pte_t entry;
  75
  76         add_mm_counter(mm, rss, HPAGE_SIZE / PAGE_SIZE);
  77         if (write_access) {
  78                 entry =
  79                     pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
  80         } else
  81                 entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
  82         entry = pte_mkyoung(entry);
  83         mk_pte_huge(entry);
  84         set_pte(page_table, entry);
  85         return;
  86 }
  87 /*
  88  * This function checks for proper alignment of input addr and len parameters.
  89  */
  90 int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
  91 {
  92         if (len & ~HPAGE_MASK)
  93                 return -EINVAL;
  94         if (addr & ~HPAGE_MASK)
  95                 return -EINVAL;
  96         if (REGION_NUMBER(addr) != REGION_HPAGE)
  97                 return -EINVAL;
  98
  99         return 0;
 100 }
 101
 102 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
 103                         struct vm_area_struct *vma)
 104 {
 105         pte_t *src_pte, *dst_pte, entry;
 106         struct page *ptepage;
 107         unsigned long addr = vma->vm_start;
 108         unsigned long end = vma->vm_end;
 109
 110         while (addr < end) {
 111                 dst_pte = huge_pte_alloc(dst, addr);
 112                 if (!dst_pte)
 113                         goto nomem;
 114                 src_pte = huge_pte_offset(src, addr);
 115                 entry = *src_pte;
 116                 ptepage = pte_page(entry);
 117                 get_page(ptepage);
 118                 set_pte(dst_pte, entry);
 119                 add_mm_counter(dst, rss, HPAGE_SIZE / PAGE_SIZE);
 120                 addr += HPAGE_SIZE;
 121         }
 122         return 0;
 123 nomem:
 124         return -ENOMEM;
 125 }
 126
 127 int
 128 follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 129                     struct page **pages, struct vm_area_struct **vmas,
 130                     unsigned long *st, int *length, int i)
 131 {
 132         pte_t *ptep, pte;
 133         unsigned long start = *st;
 134         unsigned long pstart;
 135         int len = *length;
 136         struct page *page;
 137
 138         do {
 139                 pstart = start & HPAGE_MASK;
 140                 ptep = huge_pte_offset(mm, start);
 141                 pte = *ptep;
 142
 143 back1:
 144                 page = pte_page(pte);
 145                 if (pages) {
 146                         page += ((start & ~HPAGE_MASK) >> PAGE_SHIFT);
 147                         get_page(page);
 148                         pages[i] = page;
 149                 }
 150                 if (vmas)
 151                         vmas[i] = vma;
 152                 i++;
 153                 len--;
 154                 start += PAGE_SIZE;
 155                 if (((start & HPAGE_MASK) == pstart) && len &&
 156                                 (start < vma->vm_end))
 157                         goto back1;
 158         } while (len && start < vma->vm_end);
 159         *length = len;
 160         *st = start;
 161         return i;
 162 }
 163
 164 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long addr, int write)
 165 {
 166         struct page *page;
 167         pte_t *ptep;
 168
 169         if (REGION_NUMBER(addr) != REGION_HPAGE)
 170                 return ERR_PTR(-EINVAL);
 171
 172         ptep = huge_pte_offset(mm, addr);
 173         if (!ptep || pte_none(*ptep))
 174                 return NULL;
 175         page = pte_page(*ptep);
 176         page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT);
 177         return page;
 178 }
 179 int pmd_huge(pmd_t pmd)
 180 {
 181         return 0;
 182 }
 183 struct page *
 184 follow_huge_pmd(struct mm_struct *mm, unsigned long address, pmd_t *pmd, int write)
 185 {
 186         return NULL;
 187 }
 188
 189 /*
 190  * Do nothing, until we've worked out what to do!  To allow build, we
 191  * must remove reference to clear_page_range since it no longer exists.
 192  */
 193 void hugetlb_free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *prev,
 194         unsigned long start, unsigned long end)
 195 {
 196 }
 197
 198 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
 199 {
 200         struct mm_struct *mm = vma->vm_mm;
 201         unsigned long address;
 202         pte_t *pte;
 203         struct page *page;
 204
 205         BUG_ON(start & (HPAGE_SIZE - 1));
 206         BUG_ON(end & (HPAGE_SIZE - 1));
 207
 208         for (address = start; address < end; address += HPAGE_SIZE) {
 209                 pte = huge_pte_offset(mm, address);
 210                 if (pte_none(*pte))
 211                         continue;
 212                 page = pte_page(*pte);
 213                 put_page(page);
 214                 pte_clear(mm, address, pte);
 215         }
 216         add_mm_counter(mm, rss, - ((end - start) >> PAGE_SHIFT));
 217         flush_tlb_range(vma, start, end);
 218 }
 219
 220 int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
 221 {
 222         struct mm_struct *mm = current->mm;
 223         unsigned long addr;
 224         int ret = 0;
 225
 226         BUG_ON(vma->vm_start & ~HPAGE_MASK);
 227         BUG_ON(vma->vm_end & ~HPAGE_MASK);
 228
 229         spin_lock(&mm->page_table_lock);
 230         for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
 231                 unsigned long idx;
 232                 pte_t *pte = huge_pte_alloc(mm, addr);
 233                 struct page *page;
 234
 235                 if (!pte) {
 236                         ret = -ENOMEM;
 237                         goto out;
 238                 }
 239                 if (!pte_none(*pte))
 240                         continue;
 241
 242                 idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
 243                         + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
 244                 page = find_get_page(mapping, idx);
 245                 if (!page) {
 246                         /* charge the fs quota first */
 247                         if (hugetlb_get_quota(mapping)) {
 248                                 ret = -ENOMEM;
 249                                 goto out;
 250                         }
 251                         page = alloc_huge_page();
 252                         if (!page) {
 253                                 hugetlb_put_quota(mapping);
 254                                 ret = -ENOMEM;
 255                                 goto out;
 256                         }
 257                         ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
 258                         if (! ret) {
 259                                 unlock_page(page);
 260                         } else {
 261                                 hugetlb_put_quota(mapping);
 262                                 page_cache_release(page);
 263                                 goto out;
 264                         }
 265                 }
 266                 set_huge_pte(mm, vma, page, pte, vma->vm_flags & VM_WRITE);
 267         }
 268 out:
 269         spin_unlock(&mm->page_table_lock);
 270         return ret;
 271 }
 272
 273 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 274                 unsigned long pgoff, unsigned long flags)
 275 {
 276         struct vm_area_struct *vmm;
 277
 278         if (len > RGN_MAP_LIMIT)
 279                 return -ENOMEM;
 280         if (len & ~HPAGE_MASK)
 281                 return -EINVAL;
 282         /* This code assumes that REGION_HPAGE != 0. */
 283         if ((REGION_NUMBER(addr) != REGION_HPAGE) || (addr & (HPAGE_SIZE - 1)))
 284                 addr = HPAGE_REGION_BASE;
 285         else
 286                 addr = ALIGN(addr, HPAGE_SIZE);
 287         for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
 288                 /* At this point:  (!vmm || addr < vmm->vm_end). */
 289                 if (REGION_OFFSET(addr) + len > RGN_MAP_LIMIT)
 290                         return -ENOMEM;
 291                 if (!vmm || (addr + len) <= vmm->vm_start)
 292                         return addr;
 293                 addr = ALIGN(vmm->vm_end, HPAGE_SIZE);
 294         }
 295 }
 296
 297 static int __init hugetlb_setup_sz(char *str)
 298 {
 299         u64 tr_pages;
 300         unsigned long long size;
 301
 302         if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0)
 303                 /*
 304                  * shouldn't happen, but just in case.
 305                  */
 306                 tr_pages = 0x15557000UL;
 307
 308         size = memparse(str, &str);
 309         if (*str || (size & (size-1)) || !(tr_pages & size) ||
 310                 size <= PAGE_SIZE ||
 311                 size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
 312                 printk(KERN_WARNING "Invalid huge page size specified\n");
 313                 return 1;
 314         }
 315
 316         hpage_shift = __ffs(size);
 317         /*
 318          * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT
 319          * override here with new page shift.
 320          */
 321         ia64_set_rr(HPAGE_REGION_BASE, hpage_shift << 2);
 322         return 1;
 323 }
 324 __setup("hugepagesz=", hugetlb_setup_sz);