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 static bool __init efi_virtmap_init(void) 43 { 44 efi_memory_desc_t *md; 45 46 efi_mm.pgd = pgd_alloc(&efi_mm); 47 init_new_context(NULL, &efi_mm); 48 49 for_each_efi_memory_desc(&memmap, md) { 50 phys_addr_t phys = md->phys_addr; 51 int ret; 52 53 if (!(md->attribute & EFI_MEMORY_RUNTIME)) 54 continue; 55 if (md->virt_addr == 0) 56 return false; 57 58 ret = efi_create_mapping(&efi_mm, md); 59 if (!ret) { 60 pr_info(" EFI remap %pa => %p\n", 61 &phys, (void *)(unsigned long)md->virt_addr); 62 } else { 63 pr_warn(" EFI remap %pa: failed to create mapping (%d)\n", 64 &phys, ret); 65 return false; 66 } 67 } 68 return true; 69 } 70 71 /* 72 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e., 73 * non-early mapping of the UEFI system table and virtual mappings for all 74 * EFI_MEMORY_RUNTIME regions. 75 */ 76 static int __init arm_enable_runtime_services(void) 77 { 78 u64 mapsize; 79 80 if (!efi_enabled(EFI_BOOT)) { 81 pr_info("EFI services will not be available.\n"); 82 return 0; 83 } 84 85 if (efi_runtime_disabled()) { 86 pr_info("EFI runtime services will be disabled.\n"); 87 return 0; 88 } 89 90 pr_info("Remapping and enabling EFI services.\n"); 91 92 mapsize = memmap.map_end - memmap.map; 93 memmap.map = (__force void *)ioremap_cache(memmap.phys_map, 94 mapsize); 95 if (!memmap.map) { 96 pr_err("Failed to remap EFI memory map\n"); 97 return -ENOMEM; 98 } 99 memmap.map_end = memmap.map + mapsize; 100 efi.memmap = &memmap; 101 102 efi.systab = (__force void *)ioremap_cache(efi_system_table, 103 sizeof(efi_system_table_t)); 104 if (!efi.systab) { 105 pr_err("Failed to remap EFI System Table\n"); 106 return -ENOMEM; 107 } 108 set_bit(EFI_SYSTEM_TABLES, &efi.flags); 109 110 if (!efi_virtmap_init()) { 111 pr_err("No UEFI virtual mapping was installed -- runtime services will not be available\n"); 112 return -ENOMEM; 113 } 114 115 /* Set up runtime services function pointers */ 116 efi_native_runtime_setup(); 117 set_bit(EFI_RUNTIME_SERVICES, &efi.flags); 118 119 efi.runtime_version = efi.systab->hdr.revision; 120 121 return 0; 122 } 123 early_initcall(arm_enable_runtime_services); 124 125 void efi_virtmap_load(void) 126 { 127 preempt_disable(); 128 efi_set_pgd(&efi_mm); 129 } 130 131 void efi_virtmap_unload(void) 132 { 133 efi_set_pgd(current->active_mm); 134 preempt_enable(); 135 } 136