1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2016 Linaro Ltd. <ard.biesheuvel@linaro.org>
6 #define pr_fmt(fmt) "efi: memattr: " fmt
9 #include <linux/init.h>
11 #include <linux/memblock.h>
13 #include <asm/early_ioremap.h>
15 static int __initdata tbl_size;
18 * Reserve the memory associated with the Memory Attributes configuration
19 * table, if it exists.
21 int __init efi_memattr_init(void)
23 efi_memory_attributes_table_t *tbl;
25 if (efi.mem_attr_table == EFI_INVALID_TABLE_ADDR)
28 tbl = early_memremap(efi.mem_attr_table, sizeof(*tbl));
30 pr_err("Failed to map EFI Memory Attributes table @ 0x%lx\n",
35 if (tbl->version > 1) {
36 pr_warn("Unexpected EFI Memory Attributes table version %d\n",
41 tbl_size = sizeof(*tbl) + tbl->num_entries * tbl->desc_size;
42 memblock_reserve(efi.mem_attr_table, tbl_size);
43 set_bit(EFI_MEM_ATTR, &efi.flags);
46 early_memunmap(tbl, sizeof(*tbl));
51 * Returns a copy @out of the UEFI memory descriptor @in if it is covered
52 * entirely by a UEFI memory map entry with matching attributes. The virtual
53 * address of @out is set according to the matching entry that was found.
55 static bool entry_is_valid(const efi_memory_desc_t *in, efi_memory_desc_t *out)
57 u64 in_paddr = in->phys_addr;
58 u64 in_size = in->num_pages << EFI_PAGE_SHIFT;
59 efi_memory_desc_t *md;
63 if (in->type != EFI_RUNTIME_SERVICES_CODE &&
64 in->type != EFI_RUNTIME_SERVICES_DATA) {
65 pr_warn("Entry type should be RuntimeServiceCode/Data\n");
69 if (!(in->attribute & (EFI_MEMORY_RO | EFI_MEMORY_XP))) {
70 pr_warn("Entry attributes invalid: RO and XP bits both cleared\n");
74 if (PAGE_SIZE > EFI_PAGE_SIZE &&
75 (!PAGE_ALIGNED(in->phys_addr) ||
76 !PAGE_ALIGNED(in->num_pages << EFI_PAGE_SHIFT))) {
78 * Since arm64 may execute with page sizes of up to 64 KB, the
79 * UEFI spec mandates that RuntimeServices memory regions must
80 * be 64 KB aligned. We need to validate this here since we will
81 * not be able to tighten permissions on such regions without
82 * affecting adjacent regions.
84 pr_warn("Entry address region misaligned\n");
88 for_each_efi_memory_desc(md) {
89 u64 md_paddr = md->phys_addr;
90 u64 md_size = md->num_pages << EFI_PAGE_SHIFT;
92 if (!(md->attribute & EFI_MEMORY_RUNTIME))
94 if (md->virt_addr == 0 && md->phys_addr != 0) {
95 /* no virtual mapping has been installed by the stub */
99 if (md_paddr > in_paddr || (in_paddr - md_paddr) >= md_size)
103 * This entry covers the start of @in, check whether
104 * it covers the end as well.
106 if (md_paddr + md_size < in_paddr + in_size) {
107 pr_warn("Entry covers multiple EFI memory map regions\n");
111 if (md->type != in->type) {
112 pr_warn("Entry type deviates from EFI memory map region type\n");
116 out->virt_addr = in_paddr + (md->virt_addr - md_paddr);
121 pr_warn("No matching entry found in the EFI memory map\n");
126 * To be called after the EFI page tables have been populated. If a memory
127 * attributes table is available, its contents will be used to update the
128 * mappings with tightened permissions as described by the table.
129 * This requires the UEFI memory map to have already been populated with
132 int __init efi_memattr_apply_permissions(struct mm_struct *mm,
133 efi_memattr_perm_setter fn)
135 efi_memory_attributes_table_t *tbl;
138 if (tbl_size <= sizeof(*tbl))
142 * We need the EFI memory map to be setup so we can use it to
143 * lookup the virtual addresses of all entries in the of EFI
144 * Memory Attributes table. If it isn't available, this
145 * function should not be called.
147 if (WARN_ON(!efi_enabled(EFI_MEMMAP)))
150 tbl = memremap(efi.mem_attr_table, tbl_size, MEMREMAP_WB);
152 pr_err("Failed to map EFI Memory Attributes table @ 0x%lx\n",
157 if (efi_enabled(EFI_DBG))
158 pr_info("Processing EFI Memory Attributes table:\n");
160 for (i = ret = 0; ret == 0 && i < tbl->num_entries; i++) {
161 efi_memory_desc_t md;
166 valid = entry_is_valid((void *)tbl->entry + i * tbl->desc_size,
168 size = md.num_pages << EFI_PAGE_SHIFT;
169 if (efi_enabled(EFI_DBG) || !valid)
170 pr_info("%s 0x%012llx-0x%012llx %s\n",
171 valid ? "" : "!", md.phys_addr,
172 md.phys_addr + size - 1,
173 efi_md_typeattr_format(buf, sizeof(buf), &md));
178 pr_err("Error updating mappings, skipping subsequent md's\n");