arch/tile/mm/hugetlbpage.c

   1 /*
   2  * Copyright 2010 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  *
  14  * TILE Huge TLB Page Support for Kernel.
  15  * Taken from i386 hugetlb implementation:
  16  * Copyright (C) 2002, Rohit Seth <[email protected]>
  17  */
  18
  19 #include <linux/init.h>
  20 #include <linux/fs.h>
  21 #include <linux/mm.h>
  22 #include <linux/hugetlb.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/slab.h>
  25 #include <linux/err.h>
  26 #include <linux/sysctl.h>
  27 #include <linux/mman.h>
  28 #include <asm/tlb.h>
  29 #include <asm/tlbflush.h>
  30
  31 pte_t *huge_pte_alloc(struct mm_struct *mm,
  32                       unsigned long addr, unsigned long sz)
  33 {
  34         pgd_t *pgd;
  35         pud_t *pud;
  36         pte_t *pte = NULL;
  37
  38         /* We do not yet support multiple huge page sizes. */
  39         BUG_ON(sz != PMD_SIZE);
  40
  41         pgd = pgd_offset(mm, addr);
  42         pud = pud_alloc(mm, pgd, addr);
  43         if (pud)
  44                 pte = (pte_t *) pmd_alloc(mm, pud, addr);
  45         BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
  46
  47         return pte;
  48 }
  49
  50 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
  51 {
  52         pgd_t *pgd;
  53         pud_t *pud;
  54         pmd_t *pmd = NULL;
  55
  56         pgd = pgd_offset(mm, addr);
  57         if (pgd_present(*pgd)) {
  58                 pud = pud_offset(pgd, addr);
  59                 if (pud_present(*pud))
  60                         pmd = pmd_offset(pud, addr);
  61         }
  62         return (pte_t *) pmd;
  63 }
  64
  65 #ifdef HUGETLB_TEST
  66 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
  67                               int write)
  68 {
  69         unsigned long start = address;
  70         int length = 1;
  71         int nr;
  72         struct page *page;
  73         struct vm_area_struct *vma;
  74
  75         vma = find_vma(mm, addr);
  76         if (!vma || !is_vm_hugetlb_page(vma))
  77                 return ERR_PTR(-EINVAL);
  78
  79         pte = huge_pte_offset(mm, address);
  80
  81         /* hugetlb should be locked, and hence, prefaulted */
  82         WARN_ON(!pte || pte_none(*pte));
  83
  84         page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
  85
  86         WARN_ON(!PageHead(page));
  87
  88         return page;
  89 }
  90
  91 int pmd_huge(pmd_t pmd)
  92 {
  93         return 0;
  94 }
  95
  96 int pud_huge(pud_t pud)
  97 {
  98         return 0;
  99 }
 100
 101 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 102                              pmd_t *pmd, int write)
 103 {
 104         return NULL;
 105 }
 106
 107 #else
 108
 109 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
 110                               int write)
 111 {
 112         return ERR_PTR(-EINVAL);
 113 }
 114
 115 int pmd_huge(pmd_t pmd)
 116 {
 117         return !!(pmd_val(pmd) & _PAGE_HUGE_PAGE);
 118 }
 119
 120 int pud_huge(pud_t pud)
 121 {
 122         return !!(pud_val(pud) & _PAGE_HUGE_PAGE);
 123 }
 124
 125 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 126                              pmd_t *pmd, int write)
 127 {
 128         struct page *page;
 129
 130         page = pte_page(*(pte_t *)pmd);
 131         if (page)
 132                 page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
 133         return page;
 134 }
 135
 136 struct page *follow_huge_pud(struct mm_struct *mm, unsigned long address,
 137                              pud_t *pud, int write)
 138 {
 139         struct page *page;
 140
 141         page = pte_page(*(pte_t *)pud);
 142         if (page)
 143                 page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
 144         return page;
 145 }
 146
 147 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
 148 {
 149         return 0;
 150 }
 151
 152 #endif
 153
 154 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 155 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
 156                 unsigned long addr, unsigned long len,
 157                 unsigned long pgoff, unsigned long flags)
 158 {
 159         struct hstate *h = hstate_file(file);
 160         struct mm_struct *mm = current->mm;
 161         struct vm_area_struct *vma;
 162         unsigned long start_addr;
 163
 164         if (len > mm->cached_hole_size) {
 165                 start_addr = mm->free_area_cache;
 166         } else {
 167                 start_addr = TASK_UNMAPPED_BASE;
 168                 mm->cached_hole_size = 0;
 169         }
 170
 171 full_search:
 172         addr = ALIGN(start_addr, huge_page_size(h));
 173
 174         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 175                 /* At this point:  (!vma || addr < vma->vm_end). */
 176                 if (TASK_SIZE - len < addr) {
 177                         /*
 178                          * Start a new search - just in case we missed
 179                          * some holes.
 180                          */
 181                         if (start_addr != TASK_UNMAPPED_BASE) {
 182                                 start_addr = TASK_UNMAPPED_BASE;
 183                                 mm->cached_hole_size = 0;
 184                                 goto full_search;
 185                         }
 186                         return -ENOMEM;
 187                 }
 188                 if (!vma || addr + len <= vma->vm_start) {
 189                         mm->free_area_cache = addr + len;
 190                         return addr;
 191                 }
 192                 if (addr + mm->cached_hole_size < vma->vm_start)
 193                         mm->cached_hole_size = vma->vm_start - addr;
 194                 addr = ALIGN(vma->vm_end, huge_page_size(h));
 195         }
 196 }
 197
 198 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
 199                 unsigned long addr0, unsigned long len,
 200                 unsigned long pgoff, unsigned long flags)
 201 {
 202         struct hstate *h = hstate_file(file);
 203         struct mm_struct *mm = current->mm;
 204         struct vm_area_struct *vma, *prev_vma;
 205         unsigned long base = mm->mmap_base, addr = addr0;
 206         unsigned long largest_hole = mm->cached_hole_size;
 207         int first_time = 1;
 208
 209         /* don't allow allocations above current base */
 210         if (mm->free_area_cache > base)
 211                 mm->free_area_cache = base;
 212
 213         if (len <= largest_hole) {
 214                 largest_hole = 0;
 215                 mm->free_area_cache  = base;
 216         }
 217 try_again:
 218         /* make sure it can fit in the remaining address space */
 219         if (mm->free_area_cache < len)
 220                 goto fail;
 221
 222         /* either no address requested or can't fit in requested address hole */
 223         addr = (mm->free_area_cache - len) & huge_page_mask(h);
 224         do {
 225                 /*
 226                  * Lookup failure means no vma is above this address,
 227                  * i.e. return with success:
 228                  */
 229                 vma = find_vma_prev(mm, addr, &prev_vma);
 230                 if (!vma) {
 231                         return addr;
 232                         break;
 233                 }
 234
 235                 /*
 236                  * new region fits between prev_vma->vm_end and
 237                  * vma->vm_start, use it:
 238                  */
 239                 if (addr + len <= vma->vm_start &&
 240                             (!prev_vma || (addr >= prev_vma->vm_end))) {
 241                         /* remember the address as a hint for next time */
 242                         mm->cached_hole_size = largest_hole;
 243                         mm->free_area_cache = addr;
 244                         return addr;
 245                 } else {
 246                         /* pull free_area_cache down to the first hole */
 247                         if (mm->free_area_cache == vma->vm_end) {
 248                                 mm->free_area_cache = vma->vm_start;
 249                                 mm->cached_hole_size = largest_hole;
 250                         }
 251                 }
 252
 253                 /* remember the largest hole we saw so far */
 254                 if (addr + largest_hole < vma->vm_start)
 255                         largest_hole = vma->vm_start - addr;
 256
 257                 /* try just below the current vma->vm_start */
 258                 addr = (vma->vm_start - len) & huge_page_mask(h);
 259
 260         } while (len <= vma->vm_start);
 261
 262 fail:
 263         /*
 264          * if hint left us with no space for the requested
 265          * mapping then try again:
 266          */
 267         if (first_time) {
 268                 mm->free_area_cache = base;
 269                 largest_hole = 0;
 270                 first_time = 0;
 271                 goto try_again;
 272         }
 273         /*
 274          * A failed mmap() very likely causes application failure,
 275          * so fall back to the bottom-up function here. This scenario
 276          * can happen with large stack limits and large mmap()
 277          * allocations.
 278          */
 279         mm->free_area_cache = TASK_UNMAPPED_BASE;
 280         mm->cached_hole_size = ~0UL;
 281         addr = hugetlb_get_unmapped_area_bottomup(file, addr0,
 282                         len, pgoff, flags);
 283
 284         /*
 285          * Restore the topdown base:
 286          */
 287         mm->free_area_cache = base;
 288         mm->cached_hole_size = ~0UL;
 289
 290         return addr;
 291 }
 292
 293 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 294                 unsigned long len, unsigned long pgoff, unsigned long flags)
 295 {
 296         struct hstate *h = hstate_file(file);
 297         struct mm_struct *mm = current->mm;
 298         struct vm_area_struct *vma;
 299
 300         if (len & ~huge_page_mask(h))
 301                 return -EINVAL;
 302         if (len > TASK_SIZE)
 303                 return -ENOMEM;
 304
 305         if (flags & MAP_FIXED) {
 306                 if (prepare_hugepage_range(file, addr, len))
 307                         return -EINVAL;
 308                 return addr;
 309         }
 310
 311         if (addr) {
 312                 addr = ALIGN(addr, huge_page_size(h));
 313                 vma = find_vma(mm, addr);
 314                 if (TASK_SIZE - len >= addr &&
 315                     (!vma || addr + len <= vma->vm_start))
 316                         return addr;
 317         }
 318         if (current->mm->get_unmapped_area == arch_get_unmapped_area)
 319                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 320                                 pgoff, flags);
 321         else
 322                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 323                                 pgoff, flags);
 324 }
 325
 326 static __init int setup_hugepagesz(char *opt)
 327 {
 328         unsigned long ps = memparse(opt, &opt);
 329         if (ps == PMD_SIZE) {
 330                 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
 331         } else if (ps == PUD_SIZE) {
 332                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 333         } else {
 334                 pr_err("hugepagesz: Unsupported page size %lu M\n",
 335                         ps >> 20);
 336                 return 0;
 337         }
 338         return 1;
 339 }
 340 __setup("hugepagesz=", setup_hugepagesz);
 341
 342 #endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/