xref: /openbmc/linux/arch/x86/mm/pgprot.c (revision be2b81b5)
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);
64