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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/x86/mm/pgprot.c
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// SPDX-License-Identifier: GPL-2.0

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#include <linux/export.h>

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#include <linux/mm.h>

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#include <asm/pgtable.h>

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#include <asm/mem_encrypt.h>

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static pgprot_t protection_map[16] __ro_after_init = {

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	[VM_NONE]					= PAGE_NONE,

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	[VM_READ]					= PAGE_READONLY,

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	[VM_WRITE]					= PAGE_COPY,

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	[VM_WRITE | VM_READ]				= PAGE_COPY,

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	[VM_EXEC]					= PAGE_READONLY_EXEC,

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	[VM_EXEC | VM_READ]				= PAGE_READONLY_EXEC,

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	[VM_EXEC | VM_WRITE]				= PAGE_COPY_EXEC,

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	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_COPY_EXEC,

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	[VM_SHARED]					= PAGE_NONE,

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	[VM_SHARED | VM_READ]				= PAGE_READONLY,

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	[VM_SHARED | VM_WRITE]				= PAGE_SHARED,

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	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_SHARED,

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	[VM_SHARED | VM_EXEC]				= PAGE_READONLY_EXEC,

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	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_READONLY_EXEC,

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	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_SHARED_EXEC,

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	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_SHARED_EXEC

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};

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void add_encrypt_protection_map(void)

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{

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	unsigned int i;

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	for (i = 0; i < ARRAY_SIZE(protection_map); i++)

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		protection_map[i] = pgprot_encrypted(protection_map[i]);

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}

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pgprot_t vm_get_page_prot(vm_flags_t vm_flags)

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{

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	unsigned long val = pgprot_val(protection_map[vm_flags &

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				      (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]);

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#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS

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	/*

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	 * Take the 4 protection key bits out of the vma->vm_flags value and

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	 * turn them in to the bits that we can put in to a pte.

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	 *

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	 * Only override these if Protection Keys are available (which is only

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	 * on 64-bit).

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	 */

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	if (vm_flags & VM_PKEY_BIT0)

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		val |= _PAGE_PKEY_BIT0;

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	if (vm_flags & VM_PKEY_BIT1)

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		val |= _PAGE_PKEY_BIT1;

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	if (vm_flags & VM_PKEY_BIT2)

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		val |= _PAGE_PKEY_BIT2;

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	if (vm_flags & VM_PKEY_BIT3)

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		val |= _PAGE_PKEY_BIT3;

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#endif

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	val = __sme_set(val);

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	if (val & _PAGE_PRESENT)

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		val &= __supported_pte_mask;

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	return __pgprot(val);

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}

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EXPORT_SYMBOL(vm_get_page_prot);

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