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  * Same as generic free_pgtables(), except constant PGDIR_* and pgd_offset
 191  * are hugetlb region specific.
 192  */
 193 void hugetlb_free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *prev,
 194         unsigned long start, unsigned long end)
 195 {
 196         unsigned long first = start & HUGETLB_PGDIR_MASK;
 197         unsigned long last = end + HUGETLB_PGDIR_SIZE - 1;
 198         struct mm_struct *mm = tlb->mm;
 199
 200         if (!prev) {
 201                 prev = mm->mmap;
 202                 if (!prev)
 203                         goto no_mmaps;
 204                 if (prev->vm_end > start) {
 205                         if (last > prev->vm_start)
 206                                 last = prev->vm_start;
 207                         goto no_mmaps;
 208                 }
 209         }
 210         for (;;) {
 211                 struct vm_area_struct *next = prev->vm_next;
 212
 213                 if (next) {
 214                         if (next->vm_start < start) {
 215                                 prev = next;
 216                                 continue;
 217                         }
 218                         if (last > next->vm_start)
 219                                 last = next->vm_start;
 220                 }
 221                 if (prev->vm_end > first)
 222                         first = prev->vm_end;
 223                 break;
 224         }
 225 no_mmaps:
 226         if (last < first)       /* for arches with discontiguous pgd indices */
 227                 return;
 228         clear_page_range(tlb, first, last);
 229 }
 230
 231 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
 232 {
 233         struct mm_struct *mm = vma->vm_mm;
 234         unsigned long address;
 235         pte_t *pte;
 236         struct page *page;
 237
 238         BUG_ON(start & (HPAGE_SIZE - 1));
 239         BUG_ON(end & (HPAGE_SIZE - 1));
 240
 241         for (address = start; address < end; address += HPAGE_SIZE) {
 242                 pte = huge_pte_offset(mm, address);
 243                 if (pte_none(*pte))
 244                         continue;
 245                 page = pte_page(*pte);
 246                 put_page(page);
 247                 pte_clear(mm, address, pte);
 248         }
 249         add_mm_counter(mm, rss, - ((end - start) >> PAGE_SHIFT));
 250         flush_tlb_range(vma, start, end);
 251 }
 252
 253 int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
 254 {
 255         struct mm_struct *mm = current->mm;
 256         unsigned long addr;
 257         int ret = 0;
 258
 259         BUG_ON(vma->vm_start & ~HPAGE_MASK);
 260         BUG_ON(vma->vm_end & ~HPAGE_MASK);
 261
 262         spin_lock(&mm->page_table_lock);
 263         for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
 264                 unsigned long idx;
 265                 pte_t *pte = huge_pte_alloc(mm, addr);
 266                 struct page *page;
 267
 268                 if (!pte) {
 269                         ret = -ENOMEM;
 270                         goto out;
 271                 }
 272                 if (!pte_none(*pte))
 273                         continue;
 274
 275                 idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
 276                         + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
 277                 page = find_get_page(mapping, idx);
 278                 if (!page) {
 279                         /* charge the fs quota first */
 280                         if (hugetlb_get_quota(mapping)) {
 281                                 ret = -ENOMEM;
 282                                 goto out;
 283                         }
 284                         page = alloc_huge_page();
 285                         if (!page) {
 286                                 hugetlb_put_quota(mapping);
 287                                 ret = -ENOMEM;
 288                                 goto out;
 289                         }
 290                         ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
 291                         if (! ret) {
 292                                 unlock_page(page);
 293                         } else {
 294                                 hugetlb_put_quota(mapping);
 295                                 page_cache_release(page);
 296                                 goto out;
 297                         }
 298                 }
 299                 set_huge_pte(mm, vma, page, pte, vma->vm_flags & VM_WRITE);
 300         }
 301 out:
 302         spin_unlock(&mm->page_table_lock);
 303         return ret;
 304 }
 305
 306 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 307                 unsigned long pgoff, unsigned long flags)
 308 {
 309         struct vm_area_struct *vmm;
 310
 311         if (len > RGN_MAP_LIMIT)
 312                 return -ENOMEM;
 313         if (len & ~HPAGE_MASK)
 314                 return -EINVAL;
 315         /* This code assumes that REGION_HPAGE != 0. */
 316         if ((REGION_NUMBER(addr) != REGION_HPAGE) || (addr & (HPAGE_SIZE - 1)))
 317                 addr = HPAGE_REGION_BASE;
 318         else
 319                 addr = ALIGN(addr, HPAGE_SIZE);
 320         for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
 321                 /* At this point:  (!vmm || addr < vmm->vm_end). */
 322                 if (REGION_OFFSET(addr) + len > RGN_MAP_LIMIT)
 323                         return -ENOMEM;
 324                 if (!vmm || (addr + len) <= vmm->vm_start)
 325                         return addr;
 326                 addr = ALIGN(vmm->vm_end, HPAGE_SIZE);
 327         }
 328 }
 329
 330 static int __init hugetlb_setup_sz(char *str)
 331 {
 332         u64 tr_pages;
 333         unsigned long long size;
 334
 335         if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0)
 336                 /*
 337                  * shouldn't happen, but just in case.
 338                  */
 339                 tr_pages = 0x15557000UL;
 340
 341         size = memparse(str, &str);
 342         if (*str || (size & (size-1)) || !(tr_pages & size) ||
 343                 size <= PAGE_SIZE ||
 344                 size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
 345                 printk(KERN_WARNING "Invalid huge page size specified\n");
 346                 return 1;
 347         }
 348
 349         hpage_shift = __ffs(size);
 350         /*
 351          * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT
 352          * override here with new page shift.
 353          */
 354         ia64_set_rr(HPAGE_REGION_BASE, hpage_shift << 2);
 355         return 1;
 356 }
 357 __setup("hugepagesz=", hugetlb_setup_sz);