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