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/sched/mm.h>
  23 #include <linux/hugetlb.h>
  24 #include <linux/pagemap.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 #include <asm/setup.h>
  32
  33 #ifdef CONFIG_HUGETLB_SUPER_PAGES
  34
  35 /*
  36  * Provide an additional huge page size (in addition to the regular default
  37  * huge page size) if no "hugepagesz" arguments are specified.
  38  * Note that it must be smaller than the default huge page size so
  39  * that it's possible to allocate them on demand from the buddy allocator.
  40  * You can change this to 64K (on a 16K build), 256K, 1M, or 4M,
  41  * or not define it at all.
  42  */
  43 #define ADDITIONAL_HUGE_SIZE (1024 * 1024UL)
  44
  45 /* "Extra" page-size multipliers, one per level of the page table. */
  46 int huge_shift[HUGE_SHIFT_ENTRIES] = {
  47 #ifdef ADDITIONAL_HUGE_SIZE
  48 #define ADDITIONAL_HUGE_SHIFT __builtin_ctzl(ADDITIONAL_HUGE_SIZE / PAGE_SIZE)
  49         [HUGE_SHIFT_PAGE] = ADDITIONAL_HUGE_SHIFT
  50 #endif
  51 };
  52
  53 #endif
  54
  55 pte_t *huge_pte_alloc(struct mm_struct *mm,
  56                       unsigned long addr, unsigned long sz)
  57 {
  58         pgd_t *pgd;
  59         pud_t *pud;
  60
  61         addr &= -sz;   /* Mask off any low bits in the address. */
  62
  63         pgd = pgd_offset(mm, addr);
  64         pud = pud_alloc(mm, pgd, addr);
  65
  66 #ifdef CONFIG_HUGETLB_SUPER_PAGES
  67         if (sz >= PGDIR_SIZE) {
  68                 BUG_ON(sz != PGDIR_SIZE &&
  69                        sz != PGDIR_SIZE << huge_shift[HUGE_SHIFT_PGDIR]);
  70                 return (pte_t *)pud;
  71         } else {
  72                 pmd_t *pmd = pmd_alloc(mm, pud, addr);
  73                 if (sz >= PMD_SIZE) {
  74                         BUG_ON(sz != PMD_SIZE &&
  75                                sz != (PMD_SIZE << huge_shift[HUGE_SHIFT_PMD]));
  76                         return (pte_t *)pmd;
  77                 }
  78                 else {
  79                         if (sz != PAGE_SIZE << huge_shift[HUGE_SHIFT_PAGE])
  80                                 panic("Unexpected page size %#lx\n", sz);
  81                         return pte_alloc_map(mm, pmd, addr);
  82                 }
  83         }
  84 #else
  85         BUG_ON(sz != PMD_SIZE);
  86         return (pte_t *) pmd_alloc(mm, pud, addr);
  87 #endif
  88 }
  89
  90 static pte_t *get_pte(pte_t *base, int index, int level)
  91 {
  92         pte_t *ptep = base + index;
  93 #ifdef CONFIG_HUGETLB_SUPER_PAGES
  94         if (!pte_present(*ptep) && huge_shift[level] != 0) {
  95                 unsigned long mask = -1UL << huge_shift[level];
  96                 pte_t *super_ptep = base + (index & mask);
  97                 pte_t pte = *super_ptep;
  98                 if (pte_present(pte) && pte_super(pte))
  99                         ptep = super_ptep;
 100         }
 101 #endif
 102         return ptep;
 103 }
 104
 105 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 106 {
 107         pgd_t *pgd;
 108         pud_t *pud;
 109         pmd_t *pmd;
 110 #ifdef CONFIG_HUGETLB_SUPER_PAGES
 111         pte_t *pte;
 112 #endif
 113
 114         /* Get the top-level page table entry. */
 115         pgd = (pgd_t *)get_pte((pte_t *)mm->pgd, pgd_index(addr), 0);
 116
 117         /* We don't have four levels. */
 118         pud = pud_offset(pgd, addr);
 119 #ifndef __PAGETABLE_PUD_FOLDED
 120 # error support fourth page table level
 121 #endif
 122         if (!pud_present(*pud))
 123                 return NULL;
 124
 125         /* Check for an L0 huge PTE, if we have three levels. */
 126 #ifndef __PAGETABLE_PMD_FOLDED
 127         if (pud_huge(*pud))
 128                 return (pte_t *)pud;
 129
 130         pmd = (pmd_t *)get_pte((pte_t *)pud_page_vaddr(*pud),
 131                                pmd_index(addr), 1);
 132         if (!pmd_present(*pmd))
 133                 return NULL;
 134 #else
 135         pmd = pmd_offset(pud, addr);
 136 #endif
 137
 138         /* Check for an L1 huge PTE. */
 139         if (pmd_huge(*pmd))
 140                 return (pte_t *)pmd;
 141
 142 #ifdef CONFIG_HUGETLB_SUPER_PAGES
 143         /* Check for an L2 huge PTE. */
 144         pte = get_pte((pte_t *)pmd_page_vaddr(*pmd), pte_index(addr), 2);
 145         if (!pte_present(*pte))
 146                 return NULL;
 147         if (pte_super(*pte))
 148                 return pte;
 149 #endif
 150
 151         return NULL;
 152 }
 153
 154 int pmd_huge(pmd_t pmd)
 155 {
 156         return !!(pmd_val(pmd) & _PAGE_HUGE_PAGE);
 157 }
 158
 159 int pud_huge(pud_t pud)
 160 {
 161         return !!(pud_val(pud) & _PAGE_HUGE_PAGE);
 162 }
 163
 164 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 165 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
 166                 unsigned long addr, unsigned long len,
 167                 unsigned long pgoff, unsigned long flags)
 168 {
 169         struct hstate *h = hstate_file(file);
 170         struct vm_unmapped_area_info info;
 171
 172         info.flags = 0;
 173         info.length = len;
 174         info.low_limit = TASK_UNMAPPED_BASE;
 175         info.high_limit = TASK_SIZE;
 176         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 177         info.align_offset = 0;
 178         return vm_unmapped_area(&info);
 179 }
 180
 181 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
 182                 unsigned long addr0, unsigned long len,
 183                 unsigned long pgoff, unsigned long flags)
 184 {
 185         struct hstate *h = hstate_file(file);
 186         struct vm_unmapped_area_info info;
 187         unsigned long addr;
 188
 189         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 190         info.length = len;
 191         info.low_limit = PAGE_SIZE;
 192         info.high_limit = current->mm->mmap_base;
 193         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 194         info.align_offset = 0;
 195         addr = vm_unmapped_area(&info);
 196
 197         /*
 198          * A failed mmap() very likely causes application failure,
 199          * so fall back to the bottom-up function here. This scenario
 200          * can happen with large stack limits and large mmap()
 201          * allocations.
 202          */
 203         if (addr & ~PAGE_MASK) {
 204                 VM_BUG_ON(addr != -ENOMEM);
 205                 info.flags = 0;
 206                 info.low_limit = TASK_UNMAPPED_BASE;
 207                 info.high_limit = TASK_SIZE;
 208                 addr = vm_unmapped_area(&info);
 209         }
 210
 211         return addr;
 212 }
 213
 214 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 215                 unsigned long len, unsigned long pgoff, unsigned long flags)
 216 {
 217         struct hstate *h = hstate_file(file);
 218         struct mm_struct *mm = current->mm;
 219         struct vm_area_struct *vma;
 220
 221         if (len & ~huge_page_mask(h))
 222                 return -EINVAL;
 223         if (len > TASK_SIZE)
 224                 return -ENOMEM;
 225
 226         if (flags & MAP_FIXED) {
 227                 if (prepare_hugepage_range(file, addr, len))
 228                         return -EINVAL;
 229                 return addr;
 230         }
 231
 232         if (addr) {
 233                 addr = ALIGN(addr, huge_page_size(h));
 234                 vma = find_vma(mm, addr);
 235                 if (TASK_SIZE - len >= addr &&
 236                     (!vma || addr + len <= vma->vm_start))
 237                         return addr;
 238         }
 239         if (current->mm->get_unmapped_area == arch_get_unmapped_area)
 240                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 241                                 pgoff, flags);
 242         else
 243                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 244                                 pgoff, flags);
 245 }
 246 #endif /* HAVE_ARCH_HUGETLB_UNMAPPED_AREA */
 247
 248 #ifdef CONFIG_HUGETLB_SUPER_PAGES
 249 static __init int __setup_hugepagesz(unsigned long ps)
 250 {
 251         int log_ps = __builtin_ctzl(ps);
 252         int level, base_shift;
 253
 254         if ((1UL << log_ps) != ps || (log_ps & 1) != 0) {
 255                 pr_warn("Not enabling %ld byte huge pages; must be a power of four\n",
 256                         ps);
 257                 return -EINVAL;
 258         }
 259
 260         if (ps > 64*1024*1024*1024UL) {
 261                 pr_warn("Not enabling %ld MB huge pages; largest legal value is 64 GB\n",
 262                         ps >> 20);
 263                 return -EINVAL;
 264         } else if (ps >= PUD_SIZE) {
 265                 static long hv_jpage_size;
 266                 if (hv_jpage_size == 0)
 267                         hv_jpage_size = hv_sysconf(HV_SYSCONF_PAGE_SIZE_JUMBO);
 268                 if (hv_jpage_size != PUD_SIZE) {
 269                         pr_warn("Not enabling >= %ld MB huge pages: hypervisor reports size %ld\n",
 270                                 PUD_SIZE >> 20, hv_jpage_size);
 271                         return -EINVAL;
 272                 }
 273                 level = 0;
 274                 base_shift = PUD_SHIFT;
 275         } else if (ps >= PMD_SIZE) {
 276                 level = 1;
 277                 base_shift = PMD_SHIFT;
 278         } else if (ps > PAGE_SIZE) {
 279                 level = 2;
 280                 base_shift = PAGE_SHIFT;
 281         } else {
 282                 pr_err("hugepagesz: huge page size %ld too small\n", ps);
 283                 return -EINVAL;
 284         }
 285
 286         if (log_ps != base_shift) {
 287                 int shift_val = log_ps - base_shift;
 288                 if (huge_shift[level] != 0) {
 289                         int old_shift = base_shift + huge_shift[level];
 290                         pr_warn("Not enabling %ld MB huge pages; already have size %ld MB\n",
 291                                 ps >> 20, (1UL << old_shift) >> 20);
 292                         return -EINVAL;
 293                 }
 294                 if (hv_set_pte_super_shift(level, shift_val) != 0) {
 295                         pr_warn("Not enabling %ld MB huge pages; no hypervisor support\n",
 296                                 ps >> 20);
 297                         return -EINVAL;
 298                 }
 299                 printk(KERN_DEBUG "Enabled %ld MB huge pages\n", ps >> 20);
 300                 huge_shift[level] = shift_val;
 301         }
 302
 303         hugetlb_add_hstate(log_ps - PAGE_SHIFT);
 304
 305         return 0;
 306 }
 307
 308 static bool saw_hugepagesz;
 309
 310 static __init int setup_hugepagesz(char *opt)
 311 {
 312         int rc;
 313
 314         if (!saw_hugepagesz) {
 315                 saw_hugepagesz = true;
 316                 memset(huge_shift, 0, sizeof(huge_shift));
 317         }
 318         rc = __setup_hugepagesz(memparse(opt, NULL));
 319         if (rc)
 320                 hugetlb_bad_size();
 321         return rc;
 322 }
 323 __setup("hugepagesz=", setup_hugepagesz);
 324
 325 #ifdef ADDITIONAL_HUGE_SIZE
 326 /*
 327  * Provide an additional huge page size if no "hugepagesz" args are given.
 328  * In that case, all the cores have properly set up their hv super_shift
 329  * already, but we need to notify the hugetlb code to enable the
 330  * new huge page size from the Linux point of view.
 331  */
 332 static __init int add_default_hugepagesz(void)
 333 {
 334         if (!saw_hugepagesz) {
 335                 BUILD_BUG_ON(ADDITIONAL_HUGE_SIZE >= PMD_SIZE ||
 336                              ADDITIONAL_HUGE_SIZE <= PAGE_SIZE);
 337                 BUILD_BUG_ON((PAGE_SIZE << ADDITIONAL_HUGE_SHIFT) !=
 338                              ADDITIONAL_HUGE_SIZE);
 339                 BUILD_BUG_ON(ADDITIONAL_HUGE_SHIFT & 1);
 340                 hugetlb_add_hstate(ADDITIONAL_HUGE_SHIFT);
 341         }
 342         return 0;
 343 }
 344 arch_initcall(add_default_hugepagesz);
 345 #endif
 346
 347 #endif /* CONFIG_HUGETLB_SUPER_PAGES */