arch/riscv/mm/pageattr.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2019 SiFive
   4  */
   5
   6 #include <linux/pagewalk.h>
   7 #include <linux/pgtable.h>
   8 #include <asm/tlbflush.h>
   9 #include <asm/bitops.h>
  10 #include <asm/set_memory.h>
  11
  12 struct pageattr_masks {
  13         pgprot_t set_mask;
  14         pgprot_t clear_mask;
  15 };
  16
  17 static unsigned long set_pageattr_masks(unsigned long val, struct mm_walk *walk)
  18 {
  19         struct pageattr_masks *masks = walk->private;
  20         unsigned long new_val = val;
  21
  22         new_val &= ~(pgprot_val(masks->clear_mask));
  23         new_val |= (pgprot_val(masks->set_mask));
  24
  25         return new_val;
  26 }
  27
  28 static int pageattr_pgd_entry(pgd_t *pgd, unsigned long addr,
  29                               unsigned long next, struct mm_walk *walk)
  30 {
  31         pgd_t val = READ_ONCE(*pgd);
  32
  33         if (pgd_leaf(val)) {
  34                 val = __pgd(set_pageattr_masks(pgd_val(val), walk));
  35                 set_pgd(pgd, val);
  36         }
  37
  38         return 0;
  39 }
  40
  41 static int pageattr_p4d_entry(p4d_t *p4d, unsigned long addr,
  42                               unsigned long next, struct mm_walk *walk)
  43 {
  44         p4d_t val = READ_ONCE(*p4d);
  45
  46         if (p4d_leaf(val)) {
  47                 val = __p4d(set_pageattr_masks(p4d_val(val), walk));
  48                 set_p4d(p4d, val);
  49         }
  50
  51         return 0;
  52 }
  53
  54 static int pageattr_pud_entry(pud_t *pud, unsigned long addr,
  55                               unsigned long next, struct mm_walk *walk)
  56 {
  57         pud_t val = READ_ONCE(*pud);
  58
  59         if (pud_leaf(val)) {
  60                 val = __pud(set_pageattr_masks(pud_val(val), walk));
  61                 set_pud(pud, val);
  62         }
  63
  64         return 0;
  65 }
  66
  67 static int pageattr_pmd_entry(pmd_t *pmd, unsigned long addr,
  68                               unsigned long next, struct mm_walk *walk)
  69 {
  70         pmd_t val = READ_ONCE(*pmd);
  71
  72         if (pmd_leaf(val)) {
  73                 val = __pmd(set_pageattr_masks(pmd_val(val), walk));
  74                 set_pmd(pmd, val);
  75         }
  76
  77         return 0;
  78 }
  79
  80 static int pageattr_pte_entry(pte_t *pte, unsigned long addr,
  81                               unsigned long next, struct mm_walk *walk)
  82 {
  83         pte_t val = READ_ONCE(*pte);
  84
  85         val = __pte(set_pageattr_masks(pte_val(val), walk));
  86         set_pte(pte, val);
  87
  88         return 0;
  89 }
  90
  91 static int pageattr_pte_hole(unsigned long addr, unsigned long next,
  92                              int depth, struct mm_walk *walk)
  93 {
  94         /* Nothing to do here */
  95         return 0;
  96 }
  97
  98 static const struct mm_walk_ops pageattr_ops = {
  99         .pgd_entry = pageattr_pgd_entry,
 100         .p4d_entry = pageattr_p4d_entry,
 101         .pud_entry = pageattr_pud_entry,
 102         .pmd_entry = pageattr_pmd_entry,
 103         .pte_entry = pageattr_pte_entry,
 104         .pte_hole = pageattr_pte_hole,
 105 };
 106
 107 static int __set_memory(unsigned long addr, int numpages, pgprot_t set_mask,
 108                         pgprot_t clear_mask)
 109 {
 110         int ret;
 111         unsigned long start = addr;
 112         unsigned long end = start + PAGE_SIZE * numpages;
 113         struct pageattr_masks masks = {
 114                 .set_mask = set_mask,
 115                 .clear_mask = clear_mask
 116         };
 117
 118         if (!numpages)
 119                 return 0;
 120
 121         mmap_read_lock(&init_mm);
 122         ret =  walk_page_range_novma(&init_mm, start, end, &pageattr_ops, NULL,
 123                                      &masks);
 124         mmap_read_unlock(&init_mm);
 125
 126         flush_tlb_kernel_range(start, end);
 127
 128         return ret;
 129 }
 130
 131 int set_memory_rw_nx(unsigned long addr, int numpages)
 132 {
 133         return __set_memory(addr, numpages, __pgprot(_PAGE_READ | _PAGE_WRITE),
 134                             __pgprot(_PAGE_EXEC));
 135 }
 136
 137 int set_memory_ro(unsigned long addr, int numpages)
 138 {
 139         return __set_memory(addr, numpages, __pgprot(_PAGE_READ),
 140                             __pgprot(_PAGE_WRITE));
 141 }
 142
 143 int set_memory_rw(unsigned long addr, int numpages)
 144 {
 145         return __set_memory(addr, numpages, __pgprot(_PAGE_READ | _PAGE_WRITE),
 146                             __pgprot(0));
 147 }
 148
 149 int set_memory_x(unsigned long addr, int numpages)
 150 {
 151         return __set_memory(addr, numpages, __pgprot(_PAGE_EXEC), __pgprot(0));
 152 }
 153
 154 int set_memory_nx(unsigned long addr, int numpages)
 155 {
 156         return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_EXEC));
 157 }
 158
 159 int set_direct_map_invalid_noflush(struct page *page)
 160 {
 161         int ret;
 162         unsigned long start = (unsigned long)page_address(page);
 163         unsigned long end = start + PAGE_SIZE;
 164         struct pageattr_masks masks = {
 165                 .set_mask = __pgprot(0),
 166                 .clear_mask = __pgprot(_PAGE_PRESENT)
 167         };
 168
 169         mmap_read_lock(&init_mm);
 170         ret = walk_page_range(&init_mm, start, end, &pageattr_ops, &masks);
 171         mmap_read_unlock(&init_mm);
 172
 173         return ret;
 174 }
 175
 176 int set_direct_map_default_noflush(struct page *page)
 177 {
 178         int ret;
 179         unsigned long start = (unsigned long)page_address(page);
 180         unsigned long end = start + PAGE_SIZE;
 181         struct pageattr_masks masks = {
 182                 .set_mask = PAGE_KERNEL,
 183                 .clear_mask = __pgprot(0)
 184         };
 185
 186         mmap_read_lock(&init_mm);
 187         ret = walk_page_range(&init_mm, start, end, &pageattr_ops, &masks);
 188         mmap_read_unlock(&init_mm);
 189
 190         return ret;
 191 }
 192
 193 #ifdef CONFIG_DEBUG_PAGEALLOC
 194 void __kernel_map_pages(struct page *page, int numpages, int enable)
 195 {
 196         if (!debug_pagealloc_enabled())
 197                 return;
 198
 199         if (enable)
 200                 __set_memory((unsigned long)page_address(page), numpages,
 201                              __pgprot(_PAGE_PRESENT), __pgprot(0));
 202         else
 203                 __set_memory((unsigned long)page_address(page), numpages,
 204                              __pgprot(0), __pgprot(_PAGE_PRESENT));
 205 }
 206 #endif
 207
 208 bool kernel_page_present(struct page *page)
 209 {
 210         unsigned long addr = (unsigned long)page_address(page);
 211         pgd_t *pgd;
 212         pud_t *pud;
 213         p4d_t *p4d;
 214         pmd_t *pmd;
 215         pte_t *pte;
 216
 217         pgd = pgd_offset_k(addr);
 218         if (!pgd_present(*pgd))
 219                 return false;
 220
 221         p4d = p4d_offset(pgd, addr);
 222         if (!p4d_present(*p4d))
 223                 return false;
 224
 225         pud = pud_offset(p4d, addr);
 226         if (!pud_present(*pud))
 227                 return false;
 228
 229         pmd = pmd_offset(pud, addr);
 230         if (!pmd_present(*pmd))
 231                 return false;
 232
 233         pte = pte_offset_kernel(pmd, addr);
 234         return pte_present(*pte);
 235 }