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 #include <linux/pgtable.h> 22 23 #include <asm/cacheflush.h> 24 #include <asm/efi.h> 25 #include <asm/mmu.h> 26 #include <asm/pgalloc.h> 27 28 #if defined(CONFIG_PTDUMP_DEBUGFS) && defined(CONFIG_ARM64) 29 #include <asm/ptdump.h> 30 31 static struct ptdump_info efi_ptdump_info = { 32 .mm = &efi_mm, 33 .markers = (struct addr_marker[]){ 34 { 0, "UEFI runtime start" }, 35 { DEFAULT_MAP_WINDOW_64, "UEFI runtime end" }, 36 { -1, NULL } 37 }, 38 .base_addr = 0, 39 }; 40 41 static int __init ptdump_init(void) 42 { 43 if (efi_enabled(EFI_RUNTIME_SERVICES)) 44 ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables"); 45 46 return 0; 47 } 48 device_initcall(ptdump_init); 49 50 #endif 51 52 static bool __init efi_virtmap_init(void) 53 { 54 efi_memory_desc_t *md; 55 56 efi_mm.pgd = pgd_alloc(&efi_mm); 57 mm_init_cpumask(&efi_mm); 58 init_new_context(NULL, &efi_mm); 59 60 for_each_efi_memory_desc(md) { 61 phys_addr_t phys = md->phys_addr; 62 int ret; 63 64 if (!(md->attribute & EFI_MEMORY_RUNTIME)) 65 continue; 66 if (md->virt_addr == 0) 67 return false; 68 69 ret = efi_create_mapping(&efi_mm, md); 70 if (ret) { 71 pr_warn(" EFI remap %pa: failed to create mapping (%d)\n", 72 &phys, ret); 73 return false; 74 } 75 } 76 77 if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions)) 78 return false; 79 80 return true; 81 } 82 83 /* 84 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e., 85 * non-early mapping of the UEFI system table and virtual mappings for all 86 * EFI_MEMORY_RUNTIME regions. 87 */ 88 static int __init arm_enable_runtime_services(void) 89 { 90 u64 mapsize; 91 92 if (!efi_enabled(EFI_BOOT)) { 93 pr_info("EFI services will not be available.\n"); 94 return 0; 95 } 96 97 efi_memmap_unmap(); 98 99 mapsize = efi.memmap.desc_size * efi.memmap.nr_map; 100 101 if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) { 102 pr_err("Failed to remap EFI memory map\n"); 103 return 0; 104 } 105 106 if (efi_soft_reserve_enabled()) { 107 efi_memory_desc_t *md; 108 109 for_each_efi_memory_desc(md) { 110 int md_size = md->num_pages << EFI_PAGE_SHIFT; 111 struct resource *res; 112 113 if (!(md->attribute & EFI_MEMORY_SP)) 114 continue; 115 116 res = kzalloc(sizeof(*res), GFP_KERNEL); 117 if (WARN_ON(!res)) 118 break; 119 120 res->start = md->phys_addr; 121 res->end = md->phys_addr + md_size - 1; 122 res->name = "Soft Reserved"; 123 res->flags = IORESOURCE_MEM; 124 res->desc = IORES_DESC_SOFT_RESERVED; 125 126 insert_resource(&iomem_resource, res); 127 } 128 } 129 130 if (efi_runtime_disabled()) { 131 pr_info("EFI runtime services will be disabled.\n"); 132 return 0; 133 } 134 135 if (efi_enabled(EFI_RUNTIME_SERVICES)) { 136 pr_info("EFI runtime services access via paravirt.\n"); 137 return 0; 138 } 139 140 pr_info("Remapping and enabling EFI services.\n"); 141 142 if (!efi_virtmap_init()) { 143 pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n"); 144 return -ENOMEM; 145 } 146 147 /* Set up runtime services function pointers */ 148 efi_native_runtime_setup(); 149 set_bit(EFI_RUNTIME_SERVICES, &efi.flags); 150 151 return 0; 152 } 153 early_initcall(arm_enable_runtime_services); 154 155 void efi_virtmap_load(void) 156 { 157 preempt_disable(); 158 efi_set_pgd(&efi_mm); 159 } 160 161 void efi_virtmap_unload(void) 162 { 163 efi_set_pgd(current->active_mm); 164 preempt_enable(); 165 } 166 167 168 static int __init arm_dmi_init(void) 169 { 170 /* 171 * On arm64/ARM, DMI depends on UEFI, and dmi_setup() needs to 172 * be called early because dmi_id_init(), which is an arch_initcall 173 * itself, depends on dmi_scan_machine() having been called already. 174 */ 175 dmi_setup(); 176 return 0; 177 } 178 core_initcall(arm_dmi_init); 179