arch/x86/mm/pgprot.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/export.h>
   4 #include <linux/mm.h>
   5 #include <asm/pgtable.h>
   6 #include <asm/mem_encrypt.h>
   7
   8 static pgprot_t protection_map[16] __ro_after_init = {
   9         [VM_NONE]                                       = PAGE_NONE,
  10         [VM_READ]                                       = PAGE_READONLY,
  11         [VM_WRITE]                                      = PAGE_COPY,
  12         [VM_WRITE | VM_READ]                            = PAGE_COPY,
  13         [VM_EXEC]                                       = PAGE_READONLY_EXEC,
  14         [VM_EXEC | VM_READ]                             = PAGE_READONLY_EXEC,
  15         [VM_EXEC | VM_WRITE]                            = PAGE_COPY_EXEC,
  16         [VM_EXEC | VM_WRITE | VM_READ]                  = PAGE_COPY_EXEC,
  17         [VM_SHARED]                                     = PAGE_NONE,
  18         [VM_SHARED | VM_READ]                           = PAGE_READONLY,
  19         [VM_SHARED | VM_WRITE]                          = PAGE_SHARED,
  20         [VM_SHARED | VM_WRITE | VM_READ]                = PAGE_SHARED,
  21         [VM_SHARED | VM_EXEC]                           = PAGE_READONLY_EXEC,
  22         [VM_SHARED | VM_EXEC | VM_READ]                 = PAGE_READONLY_EXEC,
  23         [VM_SHARED | VM_EXEC | VM_WRITE]                = PAGE_SHARED_EXEC,
  24         [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]      = PAGE_SHARED_EXEC
  25 };
  26
  27 void add_encrypt_protection_map(void)
  28 {
  29         unsigned int i;
  30
  31         for (i = 0; i < ARRAY_SIZE(protection_map); i++)
  32                 protection_map[i] = pgprot_encrypted(protection_map[i]);
  33 }
  34
  35 pgprot_t vm_get_page_prot(unsigned long vm_flags)
  36 {
  37         unsigned long val = pgprot_val(protection_map[vm_flags &
  38                                       (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]);
  39
  40 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
  41         /*
  42          * Take the 4 protection key bits out of the vma->vm_flags value and
  43          * turn them in to the bits that we can put in to a pte.
  44          *
  45          * Only override these if Protection Keys are available (which is only
  46          * on 64-bit).
  47          */
  48         if (vm_flags & VM_PKEY_BIT0)
  49                 val |= _PAGE_PKEY_BIT0;
  50         if (vm_flags & VM_PKEY_BIT1)
  51                 val |= _PAGE_PKEY_BIT1;
  52         if (vm_flags & VM_PKEY_BIT2)
  53                 val |= _PAGE_PKEY_BIT2;
  54         if (vm_flags & VM_PKEY_BIT3)
  55                 val |= _PAGE_PKEY_BIT3;
  56 #endif
  57
  58         val = __sme_set(val);
  59         if (val & _PAGE_PRESENT)
  60                 val &= __supported_pte_mask;
  61         return __pgprot(val);
  62 }
  63 EXPORT_SYMBOL(vm_get_page_prot);