1 /* 2 * Extensible Firmware Interface 3 * 4 * Based on Extensible Firmware Interface Specification version 2.4 5 * 6 * Copyright (C) 2013, 2014 Linaro Ltd. 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 */ 13 14 #include <linux/dmi.h> 15 #include <linux/efi.h> 16 #include <linux/io.h> 17 #include <linux/memblock.h> 18 #include <linux/mm_types.h> 19 #include <linux/preempt.h> 20 #include <linux/rbtree.h> 21 #include <linux/rwsem.h> 22 #include <linux/sched.h> 23 #include <linux/slab.h> 24 #include <linux/spinlock.h> 25 26 #include <asm/cacheflush.h> 27 #include <asm/efi.h> 28 #include <asm/mmu.h> 29 #include <asm/pgalloc.h> 30 #include <asm/pgtable.h> 31 32 extern u64 efi_system_table; 33 34 static struct mm_struct efi_mm = { 35 .mm_rb = RB_ROOT, 36 .mm_users = ATOMIC_INIT(2), 37 .mm_count = ATOMIC_INIT(1), 38 .mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem), 39 .page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock), 40 .mmlist = LIST_HEAD_INIT(efi_mm.mmlist), 41 }; 42 43 #ifdef CONFIG_ARM64_PTDUMP_DEBUGFS 44 #include <asm/ptdump.h> 45 46 static struct ptdump_info efi_ptdump_info = { 47 .mm = &efi_mm, 48 .markers = (struct addr_marker[]){ 49 { 0, "UEFI runtime start" }, 50 { TASK_SIZE_64, "UEFI runtime end" } 51 }, 52 .base_addr = 0, 53 }; 54 55 static int __init ptdump_init(void) 56 { 57 return ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables"); 58 } 59 device_initcall(ptdump_init); 60 61 #endif 62 63 static bool __init efi_virtmap_init(void) 64 { 65 efi_memory_desc_t *md; 66 bool systab_found; 67 68 efi_mm.pgd = pgd_alloc(&efi_mm); 69 mm_init_cpumask(&efi_mm); 70 init_new_context(NULL, &efi_mm); 71 72 systab_found = false; 73 for_each_efi_memory_desc(md) { 74 phys_addr_t phys = md->phys_addr; 75 int ret; 76 77 if (!(md->attribute & EFI_MEMORY_RUNTIME)) 78 continue; 79 if (md->virt_addr == 0) 80 return false; 81 82 ret = efi_create_mapping(&efi_mm, md); 83 if (!ret) { 84 pr_info(" EFI remap %pa => %p\n", 85 &phys, (void *)(unsigned long)md->virt_addr); 86 } else { 87 pr_warn(" EFI remap %pa: failed to create mapping (%d)\n", 88 &phys, ret); 89 return false; 90 } 91 /* 92 * If this entry covers the address of the UEFI system table, 93 * calculate and record its virtual address. 94 */ 95 if (efi_system_table >= phys && 96 efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) { 97 efi.systab = (void *)(unsigned long)(efi_system_table - 98 phys + md->virt_addr); 99 systab_found = true; 100 } 101 } 102 if (!systab_found) { 103 pr_err("No virtual mapping found for the UEFI System Table\n"); 104 return false; 105 } 106 107 if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions)) 108 return false; 109 110 return true; 111 } 112 113 /* 114 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e., 115 * non-early mapping of the UEFI system table and virtual mappings for all 116 * EFI_MEMORY_RUNTIME regions. 117 */ 118 static int __init arm_enable_runtime_services(void) 119 { 120 u64 mapsize; 121 122 if (!efi_enabled(EFI_BOOT)) { 123 pr_info("EFI services will not be available.\n"); 124 return 0; 125 } 126 127 if (efi_runtime_disabled()) { 128 pr_info("EFI runtime services will be disabled.\n"); 129 return 0; 130 } 131 132 if (efi_enabled(EFI_RUNTIME_SERVICES)) { 133 pr_info("EFI runtime services access via paravirt.\n"); 134 return 0; 135 } 136 137 pr_info("Remapping and enabling EFI services.\n"); 138 139 mapsize = efi.memmap.desc_size * efi.memmap.nr_map; 140 141 if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) { 142 pr_err("Failed to remap EFI memory map\n"); 143 return -ENOMEM; 144 } 145 146 if (!efi_virtmap_init()) { 147 pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n"); 148 return -ENOMEM; 149 } 150 151 /* Set up runtime services function pointers */ 152 efi_native_runtime_setup(); 153 set_bit(EFI_RUNTIME_SERVICES, &efi.flags); 154 155 return 0; 156 } 157 early_initcall(arm_enable_runtime_services); 158 159 void efi_virtmap_load(void) 160 { 161 preempt_disable(); 162 efi_set_pgd(&efi_mm); 163 } 164 165 void efi_virtmap_unload(void) 166 { 167 efi_set_pgd(current->active_mm); 168 preempt_enable(); 169 } 170 171 172 static int __init arm_dmi_init(void) 173 { 174 /* 175 * On arm64/ARM, DMI depends on UEFI, and dmi_scan_machine() needs to 176 * be called early because dmi_id_init(), which is an arch_initcall 177 * itself, depends on dmi_scan_machine() having been called already. 178 */ 179 dmi_scan_machine(); 180 if (dmi_available) 181 dmi_set_dump_stack_arch_desc(); 182 return 0; 183 } 184 core_initcall(arm_dmi_init); 185