1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Extensible Firmware Interface 4 * 5 * Based on Extensible Firmware Interface Specification version 2.4 6 * 7 * Copyright (C) 2013, 2014 Linaro Ltd. 8 */ 9 10 #include <linux/dmi.h> 11 #include <linux/efi.h> 12 #include <linux/io.h> 13 #include <linux/memblock.h> 14 #include <linux/mm_types.h> 15 #include <linux/preempt.h> 16 #include <linux/rbtree.h> 17 #include <linux/rwsem.h> 18 #include <linux/sched.h> 19 #include <linux/slab.h> 20 #include <linux/spinlock.h> 21 22 #include <asm/cacheflush.h> 23 #include <asm/efi.h> 24 #include <asm/mmu.h> 25 #include <asm/pgalloc.h> 26 #include <asm/pgtable.h> 27 28 extern u64 efi_system_table; 29 30 #if defined(CONFIG_PTDUMP_DEBUGFS) && defined(CONFIG_ARM64) 31 #include <asm/ptdump.h> 32 33 static struct ptdump_info efi_ptdump_info = { 34 .mm = &efi_mm, 35 .markers = (struct addr_marker[]){ 36 { 0, "UEFI runtime start" }, 37 { DEFAULT_MAP_WINDOW_64, "UEFI runtime end" }, 38 { -1, NULL } 39 }, 40 .base_addr = 0, 41 }; 42 43 static int __init ptdump_init(void) 44 { 45 if (efi_enabled(EFI_RUNTIME_SERVICES)) 46 ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables"); 47 48 return 0; 49 } 50 device_initcall(ptdump_init); 51 52 #endif 53 54 static bool __init efi_virtmap_init(void) 55 { 56 efi_memory_desc_t *md; 57 bool systab_found; 58 59 efi_mm.pgd = pgd_alloc(&efi_mm); 60 mm_init_cpumask(&efi_mm); 61 init_new_context(NULL, &efi_mm); 62 63 systab_found = false; 64 for_each_efi_memory_desc(md) { 65 phys_addr_t phys = md->phys_addr; 66 int ret; 67 68 if (!(md->attribute & EFI_MEMORY_RUNTIME)) 69 continue; 70 if (md->virt_addr == 0) 71 return false; 72 73 ret = efi_create_mapping(&efi_mm, md); 74 if (ret) { 75 pr_warn(" EFI remap %pa: failed to create mapping (%d)\n", 76 &phys, ret); 77 return false; 78 } 79 /* 80 * If this entry covers the address of the UEFI system table, 81 * calculate and record its virtual address. 82 */ 83 if (efi_system_table >= phys && 84 efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) { 85 efi.systab = (void *)(unsigned long)(efi_system_table - 86 phys + md->virt_addr); 87 systab_found = true; 88 } 89 } 90 if (!systab_found) { 91 pr_err("No virtual mapping found for the UEFI System Table\n"); 92 return false; 93 } 94 95 if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions)) 96 return false; 97 98 return true; 99 } 100 101 /* 102 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e., 103 * non-early mapping of the UEFI system table and virtual mappings for all 104 * EFI_MEMORY_RUNTIME regions. 105 */ 106 static int __init arm_enable_runtime_services(void) 107 { 108 u64 mapsize; 109 110 if (!efi_enabled(EFI_BOOT)) { 111 pr_info("EFI services will not be available.\n"); 112 return 0; 113 } 114 115 efi_memmap_unmap(); 116 117 mapsize = efi.memmap.desc_size * efi.memmap.nr_map; 118 119 if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) { 120 pr_err("Failed to remap EFI memory map\n"); 121 return 0; 122 } 123 124 if (efi_soft_reserve_enabled()) { 125 efi_memory_desc_t *md; 126 127 for_each_efi_memory_desc(md) { 128 int md_size = md->num_pages << EFI_PAGE_SHIFT; 129 struct resource *res; 130 131 if (!(md->attribute & EFI_MEMORY_SP)) 132 continue; 133 134 res = kzalloc(sizeof(*res), GFP_KERNEL); 135 if (WARN_ON(!res)) 136 break; 137 138 res->start = md->phys_addr; 139 res->end = md->phys_addr + md_size - 1; 140 res->name = "Soft Reserved"; 141 res->flags = IORESOURCE_MEM; 142 res->desc = IORES_DESC_SOFT_RESERVED; 143 144 insert_resource(&iomem_resource, res); 145 } 146 } 147 148 if (efi_runtime_disabled()) { 149 pr_info("EFI runtime services will be disabled.\n"); 150 return 0; 151 } 152 153 if (efi_enabled(EFI_RUNTIME_SERVICES)) { 154 pr_info("EFI runtime services access via paravirt.\n"); 155 return 0; 156 } 157 158 pr_info("Remapping and enabling EFI services.\n"); 159 160 if (!efi_virtmap_init()) { 161 pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n"); 162 return -ENOMEM; 163 } 164 165 /* Set up runtime services function pointers */ 166 efi_native_runtime_setup(); 167 set_bit(EFI_RUNTIME_SERVICES, &efi.flags); 168 169 return 0; 170 } 171 early_initcall(arm_enable_runtime_services); 172 173 void efi_virtmap_load(void) 174 { 175 preempt_disable(); 176 efi_set_pgd(&efi_mm); 177 } 178 179 void efi_virtmap_unload(void) 180 { 181 efi_set_pgd(current->active_mm); 182 preempt_enable(); 183 } 184 185 186 static int __init arm_dmi_init(void) 187 { 188 /* 189 * On arm64/ARM, DMI depends on UEFI, and dmi_setup() needs to 190 * be called early because dmi_id_init(), which is an arch_initcall 191 * itself, depends on dmi_scan_machine() having been called already. 192 */ 193 dmi_setup(); 194 return 0; 195 } 196 core_initcall(arm_dmi_init); 197