2 * Copyright (C) 2016 Linaro Ltd. <ard.biesheuvel@linaro.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
9 #define pr_fmt(fmt) "efi: memattr: " fmt
11 #include <linux/efi.h>
12 #include <linux/init.h>
14 #include <linux/memblock.h>
16 #include <asm/early_ioremap.h>
18 static int __initdata tbl_size;
21 * Reserve the memory associated with the Memory Attributes configuration
22 * table, if it exists.
24 int __init efi_memattr_init(void)
26 efi_memory_attributes_table_t *tbl;
28 if (efi.mem_attr_table == EFI_INVALID_TABLE_ADDR)
31 tbl = early_memremap(efi.mem_attr_table, sizeof(*tbl));
33 pr_err("Failed to map EFI Memory Attributes table @ 0x%lx\n",
38 if (tbl->version > 1) {
39 pr_warn("Unexpected EFI Memory Attributes table version %d\n",
44 tbl_size = sizeof(*tbl) + tbl->num_entries * tbl->desc_size;
45 memblock_reserve(efi.mem_attr_table, tbl_size);
48 early_memunmap(tbl, sizeof(*tbl));
53 * Returns a copy @out of the UEFI memory descriptor @in if it is covered
54 * entirely by a UEFI memory map entry with matching attributes. The virtual
55 * address of @out is set according to the matching entry that was found.
57 static bool entry_is_valid(const efi_memory_desc_t *in, efi_memory_desc_t *out)
59 u64 in_paddr = in->phys_addr;
60 u64 in_size = in->num_pages << EFI_PAGE_SHIFT;
61 efi_memory_desc_t *md;
65 if (in->type != EFI_RUNTIME_SERVICES_CODE &&
66 in->type != EFI_RUNTIME_SERVICES_DATA) {
67 pr_warn("Entry type should be RuntimeServiceCode/Data\n");
71 if (PAGE_SIZE > EFI_PAGE_SIZE &&
72 (!PAGE_ALIGNED(in->phys_addr) ||
73 !PAGE_ALIGNED(in->num_pages << EFI_PAGE_SHIFT))) {
75 * Since arm64 may execute with page sizes of up to 64 KB, the
76 * UEFI spec mandates that RuntimeServices memory regions must
77 * be 64 KB aligned. We need to validate this here since we will
78 * not be able to tighten permissions on such regions without
79 * affecting adjacent regions.
81 pr_warn("Entry address region misaligned\n");
85 for_each_efi_memory_desc(md) {
86 u64 md_paddr = md->phys_addr;
87 u64 md_size = md->num_pages << EFI_PAGE_SHIFT;
89 if (!(md->attribute & EFI_MEMORY_RUNTIME))
91 if (md->virt_addr == 0 && md->phys_addr != 0) {
92 /* no virtual mapping has been installed by the stub */
96 if (md_paddr > in_paddr || (in_paddr - md_paddr) >= md_size)
100 * This entry covers the start of @in, check whether
101 * it covers the end as well.
103 if (md_paddr + md_size < in_paddr + in_size) {
104 pr_warn("Entry covers multiple EFI memory map regions\n");
108 if (md->type != in->type) {
109 pr_warn("Entry type deviates from EFI memory map region type\n");
113 out->virt_addr = in_paddr + (md->virt_addr - md_paddr);
118 pr_warn("No matching entry found in the EFI memory map\n");
123 * To be called after the EFI page tables have been populated. If a memory
124 * attributes table is available, its contents will be used to update the
125 * mappings with tightened permissions as described by the table.
126 * This requires the UEFI memory map to have already been populated with
129 int __init efi_memattr_apply_permissions(struct mm_struct *mm,
130 efi_memattr_perm_setter fn)
132 efi_memory_attributes_table_t *tbl;
135 if (tbl_size <= sizeof(*tbl))
139 * We need the EFI memory map to be setup so we can use it to
140 * lookup the virtual addresses of all entries in the of EFI
141 * Memory Attributes table. If it isn't available, this
142 * function should not be called.
144 if (WARN_ON(!efi_enabled(EFI_MEMMAP)))
147 tbl = memremap(efi.mem_attr_table, tbl_size, MEMREMAP_WB);
149 pr_err("Failed to map EFI Memory Attributes table @ 0x%lx\n",
154 if (efi_enabled(EFI_DBG))
155 pr_info("Processing EFI Memory Attributes table:\n");
157 for (i = ret = 0; ret == 0 && i < tbl->num_entries; i++) {
158 efi_memory_desc_t md;
163 valid = entry_is_valid((void *)tbl->entry + i * tbl->desc_size,
165 size = md.num_pages << EFI_PAGE_SHIFT;
166 if (efi_enabled(EFI_DBG) || !valid)
167 pr_info("%s 0x%012llx-0x%012llx %s\n",
168 valid ? "" : "!", md.phys_addr,
169 md.phys_addr + size - 1,
170 efi_md_typeattr_format(buf, sizeof(buf), &md));