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