arch/ia64/mm/hugetlbpage.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * IA-64 Huge TLB Page Support for Kernel.
   4  *
   5  * Copyright (C) 2002-2004 Rohit Seth <rohit.seth@intel.com>
   6  * Copyright (C) 2003-2004 Ken Chen <kenneth.w.chen@intel.com>
   7  *
   8  * Sep, 2003: add numa support
   9  * Feb, 2004: dynamic hugetlb page size via boot parameter
  10  */
  11
  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/module.h>
  18 #include <linux/sysctl.h>
  19 #include <linux/log2.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 EXPORT_SYMBOL(hpage_shift);
  27
  28 pte_t *
  29 huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
  30 {
  31         unsigned long taddr = htlbpage_to_page(addr);
  32         pgd_t *pgd;
  33         pud_t *pud;
  34         pmd_t *pmd;
  35         pte_t *pte = NULL;
  36
  37         pgd = pgd_offset(mm, taddr);
  38         pud = pud_alloc(mm, pgd, taddr);
  39         if (pud) {
  40                 pmd = pmd_alloc(mm, pud, taddr);
  41                 if (pmd)
  42                         pte = pte_alloc_map(mm, pmd, taddr);
  43         }
  44         return pte;
  45 }
  46
  47 pte_t *
  48 huge_pte_offset (struct mm_struct *mm, unsigned long addr, unsigned long sz)
  49 {
  50         unsigned long taddr = htlbpage_to_page(addr);
  51         pgd_t *pgd;
  52         pud_t *pud;
  53         pmd_t *pmd;
  54         pte_t *pte = NULL;
  55
  56         pgd = pgd_offset(mm, taddr);
  57         if (pgd_present(*pgd)) {
  58                 pud = pud_offset(pgd, taddr);
  59                 if (pud_present(*pud)) {
  60                         pmd = pmd_offset(pud, taddr);
  61                         if (pmd_present(*pmd))
  62                                 pte = pte_offset_map(pmd, taddr);
  63                 }
  64         }
  65
  66         return pte;
  67 }
  68
  69 #define mk_pte_huge(entry) { pte_val(entry) |= _PAGE_P; }
  70
  71 /*
  72  * Don't actually need to do any preparation, but need to make sure
  73  * the address is in the right region.
  74  */
  75 int prepare_hugepage_range(struct file *file,
  76                         unsigned long addr, unsigned long len)
  77 {
  78         if (len & ~HPAGE_MASK)
  79                 return -EINVAL;
  80         if (addr & ~HPAGE_MASK)
  81                 return -EINVAL;
  82         if (REGION_NUMBER(addr) != RGN_HPAGE)
  83                 return -EINVAL;
  84
  85         return 0;
  86 }
  87
  88 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long addr, int write)
  89 {
  90         struct page *page;
  91         pte_t *ptep;
  92
  93         if (REGION_NUMBER(addr) != RGN_HPAGE)
  94                 return ERR_PTR(-EINVAL);
  95
  96         ptep = huge_pte_offset(mm, addr, HPAGE_SIZE);
  97         if (!ptep || pte_none(*ptep))
  98                 return NULL;
  99         page = pte_page(*ptep);
 100         page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT);
 101         return page;
 102 }
 103 int pmd_huge(pmd_t pmd)
 104 {
 105         return 0;
 106 }
 107
 108 int pud_huge(pud_t pud)
 109 {
 110         return 0;
 111 }
 112
 113 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 114                         unsigned long addr, unsigned long end,
 115                         unsigned long floor, unsigned long ceiling)
 116 {
 117         /*
 118          * This is called to free hugetlb page tables.
 119          *
 120          * The offset of these addresses from the base of the hugetlb
 121          * region must be scaled down by HPAGE_SIZE/PAGE_SIZE so that
 122          * the standard free_pgd_range will free the right page tables.
 123          *
 124          * If floor and ceiling are also in the hugetlb region, they
 125          * must likewise be scaled down; but if outside, left unchanged.
 126          */
 127
 128         addr = htlbpage_to_page(addr);
 129         end  = htlbpage_to_page(end);
 130         if (REGION_NUMBER(floor) == RGN_HPAGE)
 131                 floor = htlbpage_to_page(floor);
 132         if (REGION_NUMBER(ceiling) == RGN_HPAGE)
 133                 ceiling = htlbpage_to_page(ceiling);
 134
 135         free_pgd_range(tlb, addr, end, floor, ceiling);
 136 }
 137
 138 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 139                 unsigned long pgoff, unsigned long flags)
 140 {
 141         struct vm_unmapped_area_info info;
 142
 143         if (len > RGN_MAP_LIMIT)
 144                 return -ENOMEM;
 145         if (len & ~HPAGE_MASK)
 146                 return -EINVAL;
 147
 148         /* Handle MAP_FIXED */
 149         if (flags & MAP_FIXED) {
 150                 if (prepare_hugepage_range(file, addr, len))
 151                         return -EINVAL;
 152                 return addr;
 153         }
 154
 155         /* This code assumes that RGN_HPAGE != 0. */
 156         if ((REGION_NUMBER(addr) != RGN_HPAGE) || (addr & (HPAGE_SIZE - 1)))
 157                 addr = HPAGE_REGION_BASE;
 158
 159         info.flags = 0;
 160         info.length = len;
 161         info.low_limit = addr;
 162         info.high_limit = HPAGE_REGION_BASE + RGN_MAP_LIMIT;
 163         info.align_mask = PAGE_MASK & (HPAGE_SIZE - 1);
 164         info.align_offset = 0;
 165         return vm_unmapped_area(&info);
 166 }
 167
 168 static int __init hugetlb_setup_sz(char *str)
 169 {
 170         u64 tr_pages;
 171         unsigned long long size;
 172
 173         if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0)
 174                 /*
 175                  * shouldn't happen, but just in case.
 176                  */
 177                 tr_pages = 0x15557000UL;
 178
 179         size = memparse(str, &str);
 180         if (*str || !is_power_of_2(size) || !(tr_pages & size) ||
 181                 size <= PAGE_SIZE ||
 182                 size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
 183                 printk(KERN_WARNING "Invalid huge page size specified\n");
 184                 return 1;
 185         }
 186
 187         hpage_shift = __ffs(size);
 188         /*
 189          * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT
 190          * override here with new page shift.
 191          */
 192         ia64_set_rr(HPAGE_REGION_BASE, hpage_shift << 2);
 193         return 0;
 194 }
 195 early_param("hugepagesz", hugetlb_setup_sz);