linux/drivers/firmware/efi/memattr.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2016 Linaro Ltd. <[email protected]>
 */

#define pr_fmt(fmt) …

#include <linux/efi.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/memblock.h>

#include <asm/early_ioremap.h>

static int __initdata tbl_size;
unsigned long __ro_after_init efi_mem_attr_table = …;

/*
 * Reserve the memory associated with the Memory Attributes configuration
 * table, if it exists.
 */
int __init efi_memattr_init(void)
{ … }

/*
 * Returns a copy @out of the UEFI memory descriptor @in if it is covered
 * entirely by a UEFI memory map entry with matching attributes. The virtual
 * address of @out is set according to the matching entry that was found.
 */
static bool entry_is_valid(const efi_memory_desc_t *in, efi_memory_desc_t *out)
{ … }

/*
 * To be called after the EFI page tables have been populated. If a memory
 * attributes table is available, its contents will be used to update the
 * mappings with tightened permissions as described by the table.
 * This requires the UEFI memory map to have already been populated with
 * virtual addresses.
 */
int __init efi_memattr_apply_permissions(struct mm_struct *mm,
					 efi_memattr_perm_setter fn)
{ … }