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