drivers/firmware/efi/efi.c

   1 /*
   2  * efi.c - EFI subsystem
   3  *
   4  * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
   5  * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
   6  * Copyright (C) 2013 Tom Gundersen <teg@jklm.no>
   7  *
   8  * This code registers /sys/firmware/efi{,/efivars} when EFI is supported,
   9  * allowing the efivarfs to be mounted or the efivars module to be loaded.
  10  * The existance of /sys/firmware/efi may also be used by userspace to
  11  * determine that the system supports EFI.
  12  *
  13  * This file is released under the GPLv2.
  14  */
  15
  16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17
  18 #include <linux/kobject.h>
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21 #include <linux/device.h>
  22 #include <linux/efi.h>
  23 #include <linux/of.h>
  24 #include <linux/of_fdt.h>
  25 #include <linux/io.h>
  26
  27 struct efi __read_mostly efi = {
  28         .mps        = EFI_INVALID_TABLE_ADDR,
  29         .acpi       = EFI_INVALID_TABLE_ADDR,
  30         .acpi20     = EFI_INVALID_TABLE_ADDR,
  31         .smbios     = EFI_INVALID_TABLE_ADDR,
  32         .sal_systab = EFI_INVALID_TABLE_ADDR,
  33         .boot_info  = EFI_INVALID_TABLE_ADDR,
  34         .hcdp       = EFI_INVALID_TABLE_ADDR,
  35         .uga        = EFI_INVALID_TABLE_ADDR,
  36         .uv_systab  = EFI_INVALID_TABLE_ADDR,
  37         .fw_vendor  = EFI_INVALID_TABLE_ADDR,
  38         .runtime    = EFI_INVALID_TABLE_ADDR,
  39         .config_table  = EFI_INVALID_TABLE_ADDR,
  40 };
  41 EXPORT_SYMBOL(efi);
  42
  43 static struct kobject *efi_kobj;
  44 static struct kobject *efivars_kobj;
  45
  46 /*
  47  * Let's not leave out systab information that snuck into
  48  * the efivars driver
  49  */
  50 static ssize_t systab_show(struct kobject *kobj,
  51                            struct kobj_attribute *attr, char *buf)
  52 {
  53         char *str = buf;
  54
  55         if (!kobj || !buf)
  56                 return -EINVAL;
  57
  58         if (efi.mps != EFI_INVALID_TABLE_ADDR)
  59                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
  60         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
  61                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
  62         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
  63                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
  64         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
  65                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
  66         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
  67                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
  68         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
  69                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
  70         if (efi.uga != EFI_INVALID_TABLE_ADDR)
  71                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
  72
  73         return str - buf;
  74 }
  75
  76 static struct kobj_attribute efi_attr_systab =
  77                         __ATTR(systab, 0400, systab_show, NULL);
  78
  79 #define EFI_FIELD(var) efi.var
  80
  81 #define EFI_ATTR_SHOW(name) \
  82 static ssize_t name##_show(struct kobject *kobj, \
  83                                 struct kobj_attribute *attr, char *buf) \
  84 { \
  85         return sprintf(buf, "0x%lx\n", EFI_FIELD(name)); \
  86 }
  87
  88 EFI_ATTR_SHOW(fw_vendor);
  89 EFI_ATTR_SHOW(runtime);
  90 EFI_ATTR_SHOW(config_table);
  91
  92 static struct kobj_attribute efi_attr_fw_vendor = __ATTR_RO(fw_vendor);
  93 static struct kobj_attribute efi_attr_runtime = __ATTR_RO(runtime);
  94 static struct kobj_attribute efi_attr_config_table = __ATTR_RO(config_table);
  95
  96 static struct attribute *efi_subsys_attrs[] = {
  97         &efi_attr_systab.attr,
  98         &efi_attr_fw_vendor.attr,
  99         &efi_attr_runtime.attr,
 100         &efi_attr_config_table.attr,
 101         NULL,
 102 };
 103
 104 static umode_t efi_attr_is_visible(struct kobject *kobj,
 105                                    struct attribute *attr, int n)
 106 {
 107         umode_t mode = attr->mode;
 108
 109         if (attr == &efi_attr_fw_vendor.attr)
 110                 return (efi.fw_vendor == EFI_INVALID_TABLE_ADDR) ? 0 : mode;
 111         else if (attr == &efi_attr_runtime.attr)
 112                 return (efi.runtime == EFI_INVALID_TABLE_ADDR) ? 0 : mode;
 113         else if (attr == &efi_attr_config_table.attr)
 114                 return (efi.config_table == EFI_INVALID_TABLE_ADDR) ? 0 : mode;
 115
 116         return mode;
 117 }
 118
 119 static struct attribute_group efi_subsys_attr_group = {
 120         .attrs = efi_subsys_attrs,
 121         .is_visible = efi_attr_is_visible,
 122 };
 123
 124 static struct efivars generic_efivars;
 125 static struct efivar_operations generic_ops;
 126
 127 static int generic_ops_register(void)
 128 {
 129         generic_ops.get_variable = efi.get_variable;
 130         generic_ops.set_variable = efi.set_variable;
 131         generic_ops.get_next_variable = efi.get_next_variable;
 132         generic_ops.query_variable_store = efi_query_variable_store;
 133
 134         return efivars_register(&generic_efivars, &generic_ops, efi_kobj);
 135 }
 136
 137 static void generic_ops_unregister(void)
 138 {
 139         efivars_unregister(&generic_efivars);
 140 }
 141
 142 /*
 143  * We register the efi subsystem with the firmware subsystem and the
 144  * efivars subsystem with the efi subsystem, if the system was booted with
 145  * EFI.
 146  */
 147 static int __init efisubsys_init(void)
 148 {
 149         int error;
 150
 151         if (!efi_enabled(EFI_BOOT))
 152                 return 0;
 153
 154         /* We register the efi directory at /sys/firmware/efi */
 155         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
 156         if (!efi_kobj) {
 157                 pr_err("efi: Firmware registration failed.\n");
 158                 return -ENOMEM;
 159         }
 160
 161         error = generic_ops_register();
 162         if (error)
 163                 goto err_put;
 164
 165         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
 166         if (error) {
 167                 pr_err("efi: Sysfs attribute export failed with error %d.\n",
 168                        error);
 169                 goto err_unregister;
 170         }
 171
 172         error = efi_runtime_map_init(efi_kobj);
 173         if (error)
 174                 goto err_remove_group;
 175
 176         /* and the standard mountpoint for efivarfs */
 177         efivars_kobj = kobject_create_and_add("efivars", efi_kobj);
 178         if (!efivars_kobj) {
 179                 pr_err("efivars: Subsystem registration failed.\n");
 180                 error = -ENOMEM;
 181                 goto err_remove_group;
 182         }
 183
 184         return 0;
 185
 186 err_remove_group:
 187         sysfs_remove_group(efi_kobj, &efi_subsys_attr_group);
 188 err_unregister:
 189         generic_ops_unregister();
 190 err_put:
 191         kobject_put(efi_kobj);
 192         return error;
 193 }
 194
 195 subsys_initcall(efisubsys_init);
 196
 197
 198 /*
 199  * We can't ioremap data in EFI boot services RAM, because we've already mapped
 200  * it as RAM.  So, look it up in the existing EFI memory map instead.  Only
 201  * callable after efi_enter_virtual_mode and before efi_free_boot_services.
 202  */
 203 void __iomem *efi_lookup_mapped_addr(u64 phys_addr)
 204 {
 205         struct efi_memory_map *map;
 206         void *p;
 207         map = efi.memmap;
 208         if (!map)
 209                 return NULL;
 210         if (WARN_ON(!map->map))
 211                 return NULL;
 212         for (p = map->map; p < map->map_end; p += map->desc_size) {
 213                 efi_memory_desc_t *md = p;
 214                 u64 size = md->num_pages << EFI_PAGE_SHIFT;
 215                 u64 end = md->phys_addr + size;
 216                 if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
 217                     md->type != EFI_BOOT_SERVICES_CODE &&
 218                     md->type != EFI_BOOT_SERVICES_DATA)
 219                         continue;
 220                 if (!md->virt_addr)
 221                         continue;
 222                 if (phys_addr >= md->phys_addr && phys_addr < end) {
 223                         phys_addr += md->virt_addr - md->phys_addr;
 224                         return (__force void __iomem *)(unsigned long)phys_addr;
 225                 }
 226         }
 227         return NULL;
 228 }
 229
 230 static __initdata efi_config_table_type_t common_tables[] = {
 231         {ACPI_20_TABLE_GUID, "ACPI 2.0", &efi.acpi20},
 232         {ACPI_TABLE_GUID, "ACPI", &efi.acpi},
 233         {HCDP_TABLE_GUID, "HCDP", &efi.hcdp},
 234         {MPS_TABLE_GUID, "MPS", &efi.mps},
 235         {SAL_SYSTEM_TABLE_GUID, "SALsystab", &efi.sal_systab},
 236         {SMBIOS_TABLE_GUID, "SMBIOS", &efi.smbios},
 237         {UGA_IO_PROTOCOL_GUID, "UGA", &efi.uga},
 238         {NULL_GUID, NULL, NULL},
 239 };
 240
 241 static __init int match_config_table(efi_guid_t *guid,
 242                                      unsigned long table,
 243                                      efi_config_table_type_t *table_types)
 244 {
 245         u8 str[EFI_VARIABLE_GUID_LEN + 1];
 246         int i;
 247
 248         if (table_types) {
 249                 efi_guid_unparse(guid, str);
 250
 251                 for (i = 0; efi_guidcmp(table_types[i].guid, NULL_GUID); i++) {
 252                         efi_guid_unparse(&table_types[i].guid, str);
 253
 254                         if (!efi_guidcmp(*guid, table_types[i].guid)) {
 255                                 *(table_types[i].ptr) = table;
 256                                 pr_cont(" %s=0x%lx ",
 257                                         table_types[i].name, table);
 258                                 return 1;
 259                         }
 260                 }
 261         }
 262
 263         return 0;
 264 }
 265
 266 int __init efi_config_init(efi_config_table_type_t *arch_tables)
 267 {
 268         void *config_tables, *tablep;
 269         int i, sz;
 270
 271         if (efi_enabled(EFI_64BIT))
 272                 sz = sizeof(efi_config_table_64_t);
 273         else
 274                 sz = sizeof(efi_config_table_32_t);
 275
 276         /*
 277          * Let's see what config tables the firmware passed to us.
 278          */
 279         config_tables = early_memremap(efi.systab->tables,
 280                                        efi.systab->nr_tables * sz);
 281         if (config_tables == NULL) {
 282                 pr_err("Could not map Configuration table!\n");
 283                 return -ENOMEM;
 284         }
 285
 286         tablep = config_tables;
 287         pr_info("");
 288         for (i = 0; i < efi.systab->nr_tables; i++) {
 289                 efi_guid_t guid;
 290                 unsigned long table;
 291
 292                 if (efi_enabled(EFI_64BIT)) {
 293                         u64 table64;
 294                         guid = ((efi_config_table_64_t *)tablep)->guid;
 295                         table64 = ((efi_config_table_64_t *)tablep)->table;
 296                         table = table64;
 297 #ifndef CONFIG_64BIT
 298                         if (table64 >> 32) {
 299                                 pr_cont("\n");
 300                                 pr_err("Table located above 4GB, disabling EFI.\n");
 301                                 early_iounmap(config_tables,
 302                                                efi.systab->nr_tables * sz);
 303                                 return -EINVAL;
 304                         }
 305 #endif
 306                 } else {
 307                         guid = ((efi_config_table_32_t *)tablep)->guid;
 308                         table = ((efi_config_table_32_t *)tablep)->table;
 309                 }
 310
 311                 if (!match_config_table(&guid, table, common_tables))
 312                         match_config_table(&guid, table, arch_tables);
 313
 314                 tablep += sz;
 315         }
 316         pr_cont("\n");
 317         early_iounmap(config_tables, efi.systab->nr_tables * sz);
 318
 319         set_bit(EFI_CONFIG_TABLES, &efi.flags);
 320
 321         return 0;
 322 }
 323
 324 #ifdef CONFIG_EFI_PARAMS_FROM_FDT
 325
 326 #define UEFI_PARAM(name, prop, field)                      \
 327         {                                                  \
 328                 { name },                                  \
 329                 { prop },                                  \
 330                 offsetof(struct efi_fdt_params, field),    \
 331                 FIELD_SIZEOF(struct efi_fdt_params, field) \
 332         }
 333
 334 static __initdata struct {
 335         const char name[32];
 336         const char propname[32];
 337         int offset;
 338         int size;
 339 } dt_params[] = {
 340         UEFI_PARAM("System Table", "linux,uefi-system-table", system_table),
 341         UEFI_PARAM("MemMap Address", "linux,uefi-mmap-start", mmap),
 342         UEFI_PARAM("MemMap Size", "linux,uefi-mmap-size", mmap_size),
 343         UEFI_PARAM("MemMap Desc. Size", "linux,uefi-mmap-desc-size", desc_size),
 344         UEFI_PARAM("MemMap Desc. Version", "linux,uefi-mmap-desc-ver", desc_ver)
 345 };
 346
 347 struct param_info {
 348         int verbose;
 349         void *params;
 350 };
 351
 352 static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
 353                                        int depth, void *data)
 354 {
 355         struct param_info *info = data;
 356         void *prop, *dest;
 357         unsigned long len;
 358         u64 val;
 359         int i;
 360
 361         if (depth != 1 ||
 362             (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
 363                 return 0;
 364
 365         pr_info("Getting parameters from FDT:\n");
 366
 367         for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
 368                 prop = of_get_flat_dt_prop(node, dt_params[i].propname, &len);
 369                 if (!prop) {
 370                         pr_err("Can't find %s in device tree!\n",
 371                                dt_params[i].name);
 372                         return 0;
 373                 }
 374                 dest = info->params + dt_params[i].offset;
 375
 376                 val = of_read_number(prop, len / sizeof(u32));
 377
 378                 if (dt_params[i].size == sizeof(u32))
 379                         *(u32 *)dest = val;
 380                 else
 381                         *(u64 *)dest = val;
 382
 383                 if (info->verbose)
 384                         pr_info("  %s: 0x%0*llx\n", dt_params[i].name,
 385                                 dt_params[i].size * 2, val);
 386         }
 387         return 1;
 388 }
 389
 390 int __init efi_get_fdt_params(struct efi_fdt_params *params, int verbose)
 391 {
 392         struct param_info info;
 393
 394         info.verbose = verbose;
 395         info.params = params;
 396
 397         return of_scan_flat_dt(fdt_find_uefi_params, &info);
 398 }
 399 #endif /* CONFIG_EFI_PARAMS_FROM_FDT */