arch/sparc/mm/hugetlbpage.c

   1 /*
   2  * SPARC64 Huge TLB page support.
   3  *
   4  * Copyright (C) 2002, 2003, 2006 David S. Miller (davem@davemloft.net)
   5  */
   6
   7 #include <linux/init.h>
   8 #include <linux/module.h>
   9 #include <linux/fs.h>
  10 #include <linux/mm.h>
  11 #include <linux/hugetlb.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/slab.h>
  14 #include <linux/sysctl.h>
  15
  16 #include <asm/mman.h>
  17 #include <asm/pgalloc.h>
  18 #include <asm/tlb.h>
  19 #include <asm/tlbflush.h>
  20 #include <asm/cacheflush.h>
  21 #include <asm/mmu_context.h>
  22
  23 /* Slightly simplified from the non-hugepage variant because by
  24  * definition we don't have to worry about any page coloring stuff
  25  */
  26 #define VA_EXCLUDE_START (0x0000080000000000UL - (1UL << 32UL))
  27 #define VA_EXCLUDE_END   (0xfffff80000000000UL + (1UL << 32UL))
  28
  29 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *filp,
  30                                                         unsigned long addr,
  31                                                         unsigned long len,
  32                                                         unsigned long pgoff,
  33                                                         unsigned long flags)
  34 {
  35         struct mm_struct *mm = current->mm;
  36         struct vm_area_struct * vma;
  37         unsigned long task_size = TASK_SIZE;
  38         unsigned long start_addr;
  39
  40         if (test_thread_flag(TIF_32BIT))
  41                 task_size = STACK_TOP32;
  42         if (unlikely(len >= VA_EXCLUDE_START))
  43                 return -ENOMEM;
  44
  45         if (len > mm->cached_hole_size) {
  46                 start_addr = addr = mm->free_area_cache;
  47         } else {
  48                 start_addr = addr = TASK_UNMAPPED_BASE;
  49                 mm->cached_hole_size = 0;
  50         }
  51
  52         task_size -= len;
  53
  54 full_search:
  55         addr = ALIGN(addr, HPAGE_SIZE);
  56
  57         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
  58                 /* At this point:  (!vma || addr < vma->vm_end). */
  59                 if (addr < VA_EXCLUDE_START &&
  60                     (addr + len) >= VA_EXCLUDE_START) {
  61                         addr = VA_EXCLUDE_END;
  62                         vma = find_vma(mm, VA_EXCLUDE_END);
  63                 }
  64                 if (unlikely(task_size < addr)) {
  65                         if (start_addr != TASK_UNMAPPED_BASE) {
  66                                 start_addr = addr = TASK_UNMAPPED_BASE;
  67                                 mm->cached_hole_size = 0;
  68                                 goto full_search;
  69                         }
  70                         return -ENOMEM;
  71                 }
  72                 if (likely(!vma || addr + len <= vma->vm_start)) {
  73                         /*
  74                          * Remember the place where we stopped the search:
  75                          */
  76                         mm->free_area_cache = addr + len;
  77                         return addr;
  78                 }
  79                 if (addr + mm->cached_hole_size < vma->vm_start)
  80                         mm->cached_hole_size = vma->vm_start - addr;
  81
  82                 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
  83         }
  84 }
  85
  86 static unsigned long
  87 hugetlb_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
  88                                   const unsigned long len,
  89                                   const unsigned long pgoff,
  90                                   const unsigned long flags)
  91 {
  92         struct vm_area_struct *vma;
  93         struct mm_struct *mm = current->mm;
  94         unsigned long addr = addr0;
  95
  96         /* This should only ever run for 32-bit processes.  */
  97         BUG_ON(!test_thread_flag(TIF_32BIT));
  98
  99         /* check if free_area_cache is useful for us */
 100         if (len <= mm->cached_hole_size) {
 101                 mm->cached_hole_size = 0;
 102                 mm->free_area_cache = mm->mmap_base;
 103         }
 104
 105         /* either no address requested or can't fit in requested address hole */
 106         addr = mm->free_area_cache & HPAGE_MASK;
 107
 108         /* make sure it can fit in the remaining address space */
 109         if (likely(addr > len)) {
 110                 vma = find_vma(mm, addr-len);
 111                 if (!vma || addr <= vma->vm_start) {
 112                         /* remember the address as a hint for next time */
 113                         return (mm->free_area_cache = addr-len);
 114                 }
 115         }
 116
 117         if (unlikely(mm->mmap_base < len))
 118                 goto bottomup;
 119
 120         addr = (mm->mmap_base-len) & HPAGE_MASK;
 121
 122         do {
 123                 /*
 124                  * Lookup failure means no vma is above this address,
 125                  * else if new region fits below vma->vm_start,
 126                  * return with success:
 127                  */
 128                 vma = find_vma(mm, addr);
 129                 if (likely(!vma || addr+len <= vma->vm_start)) {
 130                         /* remember the address as a hint for next time */
 131                         return (mm->free_area_cache = addr);
 132                 }
 133
 134                 /* remember the largest hole we saw so far */
 135                 if (addr + mm->cached_hole_size < vma->vm_start)
 136                         mm->cached_hole_size = vma->vm_start - addr;
 137
 138                 /* try just below the current vma->vm_start */
 139                 addr = (vma->vm_start-len) & HPAGE_MASK;
 140         } while (likely(len < vma->vm_start));
 141
 142 bottomup:
 143         /*
 144          * A failed mmap() very likely causes application failure,
 145          * so fall back to the bottom-up function here. This scenario
 146          * can happen with large stack limits and large mmap()
 147          * allocations.
 148          */
 149         mm->cached_hole_size = ~0UL;
 150         mm->free_area_cache = TASK_UNMAPPED_BASE;
 151         addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
 152         /*
 153          * Restore the topdown base:
 154          */
 155         mm->free_area_cache = mm->mmap_base;
 156         mm->cached_hole_size = ~0UL;
 157
 158         return addr;
 159 }
 160
 161 unsigned long
 162 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 163                 unsigned long len, unsigned long pgoff, unsigned long flags)
 164 {
 165         struct mm_struct *mm = current->mm;
 166         struct vm_area_struct *vma;
 167         unsigned long task_size = TASK_SIZE;
 168
 169         if (test_thread_flag(TIF_32BIT))
 170                 task_size = STACK_TOP32;
 171
 172         if (len & ~HPAGE_MASK)
 173                 return -EINVAL;
 174         if (len > task_size)
 175                 return -ENOMEM;
 176
 177         if (flags & MAP_FIXED) {
 178                 if (prepare_hugepage_range(file, addr, len))
 179                         return -EINVAL;
 180                 return addr;
 181         }
 182
 183         if (addr) {
 184                 addr = ALIGN(addr, HPAGE_SIZE);
 185                 vma = find_vma(mm, addr);
 186                 if (task_size - len >= addr &&
 187                     (!vma || addr + len <= vma->vm_start))
 188                         return addr;
 189         }
 190         if (mm->get_unmapped_area == arch_get_unmapped_area)
 191                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 192                                 pgoff, flags);
 193         else
 194                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 195                                 pgoff, flags);
 196 }
 197
 198 pte_t *huge_pte_alloc(struct mm_struct *mm,
 199                         unsigned long addr, unsigned long sz)
 200 {
 201         pgd_t *pgd;
 202         pud_t *pud;
 203         pmd_t *pmd;
 204         pte_t *pte = NULL;
 205
 206         /* We must align the address, because our caller will run
 207          * set_huge_pte_at() on whatever we return, which writes out
 208          * all of the sub-ptes for the hugepage range.  So we have
 209          * to give it the first such sub-pte.
 210          */
 211         addr &= HPAGE_MASK;
 212
 213         pgd = pgd_offset(mm, addr);
 214         pud = pud_alloc(mm, pgd, addr);
 215         if (pud) {
 216                 pmd = pmd_alloc(mm, pud, addr);
 217                 if (pmd)
 218                         pte = pte_alloc_map(mm, pmd, addr);
 219         }
 220         return pte;
 221 }
 222
 223 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 224 {
 225         pgd_t *pgd;
 226         pud_t *pud;
 227         pmd_t *pmd;
 228         pte_t *pte = NULL;
 229
 230         addr &= HPAGE_MASK;
 231
 232         pgd = pgd_offset(mm, addr);
 233         if (!pgd_none(*pgd)) {
 234                 pud = pud_offset(pgd, addr);
 235                 if (!pud_none(*pud)) {
 236                         pmd = pmd_offset(pud, addr);
 237                         if (!pmd_none(*pmd))
 238                                 pte = pte_offset_map(pmd, addr);
 239                 }
 240         }
 241         return pte;
 242 }
 243
 244 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
 245 {
 246         return 0;
 247 }
 248
 249 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 250                      pte_t *ptep, pte_t entry)
 251 {
 252         int i;
 253
 254         if (!pte_present(*ptep) && pte_present(entry))
 255                 mm->context.huge_pte_count++;
 256
 257         addr &= HPAGE_MASK;
 258         for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
 259                 set_pte_at(mm, addr, ptep, entry);
 260                 ptep++;
 261                 addr += PAGE_SIZE;
 262                 pte_val(entry) += PAGE_SIZE;
 263         }
 264 }
 265
 266 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 267                               pte_t *ptep)
 268 {
 269         pte_t entry;
 270         int i;
 271
 272         entry = *ptep;
 273         if (pte_present(entry))
 274                 mm->context.huge_pte_count--;
 275
 276         addr &= HPAGE_MASK;
 277
 278         for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
 279                 pte_clear(mm, addr, ptep);
 280                 addr += PAGE_SIZE;
 281                 ptep++;
 282         }
 283
 284         return entry;
 285 }
 286
 287 struct page *follow_huge_addr(struct mm_struct *mm,
 288                               unsigned long address, int write)
 289 {
 290         return ERR_PTR(-EINVAL);
 291 }
 292
 293 int pmd_huge(pmd_t pmd)
 294 {
 295         return 0;
 296 }
 297
 298 int pud_huge(pud_t pud)
 299 {
 300         return 0;
 301 }
 302
 303 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 304                              pmd_t *pmd, int write)
 305 {
 306         return NULL;
 307 }
 308
 309 static void context_reload(void *__data)
 310 {
 311         struct mm_struct *mm = __data;
 312
 313         if (mm == current->mm)
 314                 load_secondary_context(mm);
 315 }
 316
 317 void hugetlb_prefault_arch_hook(struct mm_struct *mm)
 318 {
 319         struct tsb_config *tp = &mm->context.tsb_block[MM_TSB_HUGE];
 320
 321         if (likely(tp->tsb != NULL))
 322                 return;
 323
 324         tsb_grow(mm, MM_TSB_HUGE, 0);
 325         tsb_context_switch(mm);
 326         smp_tsb_sync(mm);
 327
 328         /* On UltraSPARC-III+ and later, configure the second half of
 329          * the Data-TLB for huge pages.
 330          */
 331         if (tlb_type == cheetah_plus) {
 332                 unsigned long ctx;
 333
 334                 spin_lock(&ctx_alloc_lock);
 335                 ctx = mm->context.sparc64_ctx_val;
 336                 ctx &= ~CTX_PGSZ_MASK;
 337                 ctx |= CTX_PGSZ_BASE << CTX_PGSZ0_SHIFT;
 338                 ctx |= CTX_PGSZ_HUGE << CTX_PGSZ1_SHIFT;
 339
 340                 if (ctx != mm->context.sparc64_ctx_val) {
 341                         /* When changing the page size fields, we
 342                          * must perform a context flush so that no
 343                          * stale entries match.  This flush must
 344                          * occur with the original context register
 345                          * settings.
 346                          */
 347                         do_flush_tlb_mm(mm);
 348
 349                         /* Reload the context register of all processors
 350                          * also executing in this address space.
 351                          */
 352                         mm->context.sparc64_ctx_val = ctx;
 353                         on_each_cpu(context_reload, mm, 0);
 354                 }
 355                 spin_unlock(&ctx_alloc_lock);
 356         }
 357 }