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/tlb.h>
  22 #include <asm/tlbflush.h>
  23
  24 unsigned int hpage_shift = HPAGE_SHIFT_DEFAULT;
  25 EXPORT_SYMBOL(hpage_shift);
  26
  27 pte_t *
  28 huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
  29 {
  30         unsigned long taddr = htlbpage_to_page(addr);
  31         pgd_t *pgd;
  32         p4d_t *p4d;
  33         pud_t *pud;
  34         pmd_t *pmd;
  35         pte_t *pte = NULL;
  36
  37         pgd = pgd_offset(mm, taddr);
  38         p4d = p4d_offset(pgd, taddr);
  39         pud = pud_alloc(mm, p4d, taddr);
  40         if (pud) {
  41                 pmd = pmd_alloc(mm, pud, taddr);
  42                 if (pmd)
  43                         pte = pte_alloc_map(mm, pmd, taddr);
  44         }
  45         return pte;
  46 }
  47
  48 pte_t *
  49 huge_pte_offset (struct mm_struct *mm, unsigned long addr, unsigned long sz)
  50 {
  51         unsigned long taddr = htlbpage_to_page(addr);
  52         pgd_t *pgd;
  53         p4d_t *p4d;
  54         pud_t *pud;
  55         pmd_t *pmd;
  56         pte_t *pte = NULL;
  57
  58         pgd = pgd_offset(mm, taddr);
  59         if (pgd_present(*pgd)) {
  60                 p4d = p4d_offset(pgd, addr);
  61                 if (p4d_present(*p4d)) {
  62                         pud = pud_offset(p4d, taddr);
  63                         if (pud_present(*pud)) {
  64                                 pmd = pmd_offset(pud, taddr);
  65                                 if (pmd_present(*pmd))
  66                                         pte = pte_offset_map(pmd, taddr);
  67                         }
  68                 }
  69         }
  70
  71         return pte;
  72 }
  73
  74 #define mk_pte_huge(entry) { pte_val(entry) |= _PAGE_P; }
  75
  76 /*
  77  * Don't actually need to do any preparation, but need to make sure
  78  * the address is in the right region.
  79  */
  80 int prepare_hugepage_range(struct file *file,
  81                         unsigned long addr, unsigned long len)
  82 {
  83         if (len & ~HPAGE_MASK)
  84                 return -EINVAL;
  85         if (addr & ~HPAGE_MASK)
  86                 return -EINVAL;
  87         if (REGION_NUMBER(addr) != RGN_HPAGE)
  88                 return -EINVAL;
  89
  90         return 0;
  91 }
  92
  93 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long addr, int write)
  94 {
  95         struct page *page;
  96         pte_t *ptep;
  97
  98         if (REGION_NUMBER(addr) != RGN_HPAGE)
  99                 return ERR_PTR(-EINVAL);
 100
 101         ptep = huge_pte_offset(mm, addr, HPAGE_SIZE);
 102         if (!ptep || pte_none(*ptep))
 103                 return NULL;
 104         page = pte_page(*ptep);
 105         page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT);
 106         return page;
 107 }
 108 int pmd_huge(pmd_t pmd)
 109 {
 110         return 0;
 111 }
 112
 113 int pud_huge(pud_t pud)
 114 {
 115         return 0;
 116 }
 117
 118 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 119                         unsigned long addr, unsigned long end,
 120                         unsigned long floor, unsigned long ceiling)
 121 {
 122         /*
 123          * This is called to free hugetlb page tables.
 124          *
 125          * The offset of these addresses from the base of the hugetlb
 126          * region must be scaled down by HPAGE_SIZE/PAGE_SIZE so that
 127          * the standard free_pgd_range will free the right page tables.
 128          *
 129          * If floor and ceiling are also in the hugetlb region, they
 130          * must likewise be scaled down; but if outside, left unchanged.
 131          */
 132
 133         addr = htlbpage_to_page(addr);
 134         end  = htlbpage_to_page(end);
 135         if (REGION_NUMBER(floor) == RGN_HPAGE)
 136                 floor = htlbpage_to_page(floor);
 137         if (REGION_NUMBER(ceiling) == RGN_HPAGE)
 138                 ceiling = htlbpage_to_page(ceiling);
 139
 140         free_pgd_range(tlb, addr, end, floor, ceiling);
 141 }
 142
 143 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 144                 unsigned long pgoff, unsigned long flags)
 145 {
 146         struct vm_unmapped_area_info info;
 147
 148         if (len > RGN_MAP_LIMIT)
 149                 return -ENOMEM;
 150         if (len & ~HPAGE_MASK)
 151                 return -EINVAL;
 152
 153         /* Handle MAP_FIXED */
 154         if (flags & MAP_FIXED) {
 155                 if (prepare_hugepage_range(file, addr, len))
 156                         return -EINVAL;
 157                 return addr;
 158         }
 159
 160         /* This code assumes that RGN_HPAGE != 0. */
 161         if ((REGION_NUMBER(addr) != RGN_HPAGE) || (addr & (HPAGE_SIZE - 1)))
 162                 addr = HPAGE_REGION_BASE;
 163
 164         info.flags = 0;
 165         info.length = len;
 166         info.low_limit = addr;
 167         info.high_limit = HPAGE_REGION_BASE + RGN_MAP_LIMIT;
 168         info.align_mask = PAGE_MASK & (HPAGE_SIZE - 1);
 169         info.align_offset = 0;
 170         return vm_unmapped_area(&info);
 171 }
 172
 173 static int __init hugetlb_setup_sz(char *str)
 174 {
 175         u64 tr_pages;
 176         unsigned long long size;
 177
 178         if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0)
 179                 /*
 180                  * shouldn't happen, but just in case.
 181                  */
 182                 tr_pages = 0x15557000UL;
 183
 184         size = memparse(str, &str);
 185         if (*str || !is_power_of_2(size) || !(tr_pages & size) ||
 186                 size <= PAGE_SIZE ||
 187                 size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
 188                 printk(KERN_WARNING "Invalid huge page size specified\n");
 189                 return 1;
 190         }
 191
 192         hpage_shift = __ffs(size);
 193         /*
 194          * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT
 195          * override here with new page shift.
 196          */
 197         ia64_set_rr(HPAGE_REGION_BASE, hpage_shift << 2);
 198         return 0;
 199 }
 200 early_param("hugepagesz", hugetlb_setup_sz);