arch/x86/platform/efi/efi.c

   1 /*
   2  * Common EFI (Extensible Firmware Interface) support functions
   3  * Based on Extensible Firmware Interface Specification version 1.0
   4  *
   5  * Copyright (C) 1999 VA Linux Systems
   6  * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
   7  * Copyright (C) 1999-2002 Hewlett-Packard Co.
   8  *      David Mosberger-Tang <davidm@hpl.hp.com>
   9  *      Stephane Eranian <eranian@hpl.hp.com>
  10  * Copyright (C) 2005-2008 Intel Co.
  11  *      Fenghua Yu <fenghua.yu@intel.com>
  12  *      Bibo Mao <bibo.mao@intel.com>
  13  *      Chandramouli Narayanan <mouli@linux.intel.com>
  14  *      Huang Ying <ying.huang@intel.com>
  15  *
  16  * Copied from efi_32.c to eliminate the duplicated code between EFI
  17  * 32/64 support code. --ying 2007-10-26
  18  *
  19  * All EFI Runtime Services are not implemented yet as EFI only
  20  * supports physical mode addressing on SoftSDV. This is to be fixed
  21  * in a future version.  --drummond 1999-07-20
  22  *
  23  * Implemented EFI runtime services and virtual mode calls.  --davidm
  24  *
  25  * Goutham Rao: <goutham.rao@intel.com>
  26  *      Skip non-WB memory and ignore empty memory ranges.
  27  */
  28
  29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  30
  31 #include <linux/kernel.h>
  32 #include <linux/init.h>
  33 #include <linux/efi.h>
  34 #include <linux/export.h>
  35 #include <linux/bootmem.h>
  36 #include <linux/memblock.h>
  37 #include <linux/spinlock.h>
  38 #include <linux/uaccess.h>
  39 #include <linux/time.h>
  40 #include <linux/io.h>
  41 #include <linux/reboot.h>
  42 #include <linux/bcd.h>
  43
  44 #include <asm/setup.h>
  45 #include <asm/efi.h>
  46 #include <asm/time.h>
  47 #include <asm/cacheflush.h>
  48 #include <asm/tlbflush.h>
  49 #include <asm/x86_init.h>
  50
  51 #define EFI_DEBUG       1
  52
  53 int efi_enabled;
  54 EXPORT_SYMBOL(efi_enabled);
  55
  56 struct efi __read_mostly efi = {
  57         .mps        = EFI_INVALID_TABLE_ADDR,
  58         .acpi       = EFI_INVALID_TABLE_ADDR,
  59         .acpi20     = EFI_INVALID_TABLE_ADDR,
  60         .smbios     = EFI_INVALID_TABLE_ADDR,
  61         .sal_systab = EFI_INVALID_TABLE_ADDR,
  62         .boot_info  = EFI_INVALID_TABLE_ADDR,
  63         .hcdp       = EFI_INVALID_TABLE_ADDR,
  64         .uga        = EFI_INVALID_TABLE_ADDR,
  65         .uv_systab  = EFI_INVALID_TABLE_ADDR,
  66 };
  67 EXPORT_SYMBOL(efi);
  68
  69 struct efi_memory_map memmap;
  70
  71 static struct efi efi_phys __initdata;
  72 static efi_system_table_t efi_systab __initdata;
  73
  74 static int __init setup_noefi(char *arg)
  75 {
  76         efi_enabled = 0;
  77         return 0;
  78 }
  79 early_param("noefi", setup_noefi);
  80
  81 int add_efi_memmap;
  82 EXPORT_SYMBOL(add_efi_memmap);
  83
  84 static int __init setup_add_efi_memmap(char *arg)
  85 {
  86         add_efi_memmap = 1;
  87         return 0;
  88 }
  89 early_param("add_efi_memmap", setup_add_efi_memmap);
  90
  91
  92 static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
  93 {
  94         unsigned long flags;
  95         efi_status_t status;
  96
  97         spin_lock_irqsave(&rtc_lock, flags);
  98         status = efi_call_virt2(get_time, tm, tc);
  99         spin_unlock_irqrestore(&rtc_lock, flags);
 100         return status;
 101 }
 102
 103 static efi_status_t virt_efi_set_time(efi_time_t *tm)
 104 {
 105         unsigned long flags;
 106         efi_status_t status;
 107
 108         spin_lock_irqsave(&rtc_lock, flags);
 109         status = efi_call_virt1(set_time, tm);
 110         spin_unlock_irqrestore(&rtc_lock, flags);
 111         return status;
 112 }
 113
 114 static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled,
 115                                              efi_bool_t *pending,
 116                                              efi_time_t *tm)
 117 {
 118         unsigned long flags;
 119         efi_status_t status;
 120
 121         spin_lock_irqsave(&rtc_lock, flags);
 122         status = efi_call_virt3(get_wakeup_time,
 123                                 enabled, pending, tm);
 124         spin_unlock_irqrestore(&rtc_lock, flags);
 125         return status;
 126 }
 127
 128 static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
 129 {
 130         unsigned long flags;
 131         efi_status_t status;
 132
 133         spin_lock_irqsave(&rtc_lock, flags);
 134         status = efi_call_virt2(set_wakeup_time,
 135                                 enabled, tm);
 136         spin_unlock_irqrestore(&rtc_lock, flags);
 137         return status;
 138 }
 139
 140 static efi_status_t virt_efi_get_variable(efi_char16_t *name,
 141                                           efi_guid_t *vendor,
 142                                           u32 *attr,
 143                                           unsigned long *data_size,
 144                                           void *data)
 145 {
 146         return efi_call_virt5(get_variable,
 147                               name, vendor, attr,
 148                               data_size, data);
 149 }
 150
 151 static efi_status_t virt_efi_get_next_variable(unsigned long *name_size,
 152                                                efi_char16_t *name,
 153                                                efi_guid_t *vendor)
 154 {
 155         return efi_call_virt3(get_next_variable,
 156                               name_size, name, vendor);
 157 }
 158
 159 static efi_status_t virt_efi_set_variable(efi_char16_t *name,
 160                                           efi_guid_t *vendor,
 161                                           u32 attr,
 162                                           unsigned long data_size,
 163                                           void *data)
 164 {
 165         return efi_call_virt5(set_variable,
 166                               name, vendor, attr,
 167                               data_size, data);
 168 }
 169
 170 static efi_status_t virt_efi_query_variable_info(u32 attr,
 171                                                  u64 *storage_space,
 172                                                  u64 *remaining_space,
 173                                                  u64 *max_variable_size)
 174 {
 175         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 176                 return EFI_UNSUPPORTED;
 177
 178         return efi_call_virt4(query_variable_info, attr, storage_space,
 179                               remaining_space, max_variable_size);
 180 }
 181
 182 static efi_status_t virt_efi_get_next_high_mono_count(u32 *count)
 183 {
 184         return efi_call_virt1(get_next_high_mono_count, count);
 185 }
 186
 187 static void virt_efi_reset_system(int reset_type,
 188                                   efi_status_t status,
 189                                   unsigned long data_size,
 190                                   efi_char16_t *data)
 191 {
 192         efi_call_virt4(reset_system, reset_type, status,
 193                        data_size, data);
 194 }
 195
 196 static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules,
 197                                             unsigned long count,
 198                                             unsigned long sg_list)
 199 {
 200         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 201                 return EFI_UNSUPPORTED;
 202
 203         return efi_call_virt3(update_capsule, capsules, count, sg_list);
 204 }
 205
 206 static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules,
 207                                                 unsigned long count,
 208                                                 u64 *max_size,
 209                                                 int *reset_type)
 210 {
 211         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 212                 return EFI_UNSUPPORTED;
 213
 214         return efi_call_virt4(query_capsule_caps, capsules, count, max_size,
 215                               reset_type);
 216 }
 217
 218 static efi_status_t __init phys_efi_set_virtual_address_map(
 219         unsigned long memory_map_size,
 220         unsigned long descriptor_size,
 221         u32 descriptor_version,
 222         efi_memory_desc_t *virtual_map)
 223 {
 224         efi_status_t status;
 225
 226         efi_call_phys_prelog();
 227         status = efi_call_phys4(efi_phys.set_virtual_address_map,
 228                                 memory_map_size, descriptor_size,
 229                                 descriptor_version, virtual_map);
 230         efi_call_phys_epilog();
 231         return status;
 232 }
 233
 234 static efi_status_t __init phys_efi_get_time(efi_time_t *tm,
 235                                              efi_time_cap_t *tc)
 236 {
 237         unsigned long flags;
 238         efi_status_t status;
 239
 240         spin_lock_irqsave(&rtc_lock, flags);
 241         efi_call_phys_prelog();
 242         status = efi_call_phys2(efi_phys.get_time, virt_to_phys(tm),
 243                                 virt_to_phys(tc));
 244         efi_call_phys_epilog();
 245         spin_unlock_irqrestore(&rtc_lock, flags);
 246         return status;
 247 }
 248
 249 int efi_set_rtc_mmss(unsigned long nowtime)
 250 {
 251         int real_seconds, real_minutes;
 252         efi_status_t    status;
 253         efi_time_t      eft;
 254         efi_time_cap_t  cap;
 255
 256         status = efi.get_time(&eft, &cap);
 257         if (status != EFI_SUCCESS) {
 258                 pr_err("Oops: efitime: can't read time!\n");
 259                 return -1;
 260         }
 261
 262         real_seconds = nowtime % 60;
 263         real_minutes = nowtime / 60;
 264         if (((abs(real_minutes - eft.minute) + 15)/30) & 1)
 265                 real_minutes += 30;
 266         real_minutes %= 60;
 267         eft.minute = real_minutes;
 268         eft.second = real_seconds;
 269
 270         status = efi.set_time(&eft);
 271         if (status != EFI_SUCCESS) {
 272                 pr_err("Oops: efitime: can't write time!\n");
 273                 return -1;
 274         }
 275         return 0;
 276 }
 277
 278 unsigned long efi_get_time(void)
 279 {
 280         efi_status_t status;
 281         efi_time_t eft;
 282         efi_time_cap_t cap;
 283
 284         status = efi.get_time(&eft, &cap);
 285         if (status != EFI_SUCCESS)
 286                 pr_err("Oops: efitime: can't read time!\n");
 287
 288         return mktime(eft.year, eft.month, eft.day, eft.hour,
 289                       eft.minute, eft.second);
 290 }
 291
 292 /*
 293  * Tell the kernel about the EFI memory map.  This might include
 294  * more than the max 128 entries that can fit in the e820 legacy
 295  * (zeropage) memory map.
 296  */
 297
 298 static void __init do_add_efi_memmap(void)
 299 {
 300         void *p;
 301
 302         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 303                 efi_memory_desc_t *md = p;
 304                 unsigned long long start = md->phys_addr;
 305                 unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
 306                 int e820_type;
 307
 308                 switch (md->type) {
 309                 case EFI_LOADER_CODE:
 310                 case EFI_LOADER_DATA:
 311                 case EFI_BOOT_SERVICES_CODE:
 312                 case EFI_BOOT_SERVICES_DATA:
 313                 case EFI_CONVENTIONAL_MEMORY:
 314                         if (md->attribute & EFI_MEMORY_WB)
 315                                 e820_type = E820_RAM;
 316                         else
 317                                 e820_type = E820_RESERVED;
 318                         break;
 319                 case EFI_ACPI_RECLAIM_MEMORY:
 320                         e820_type = E820_ACPI;
 321                         break;
 322                 case EFI_ACPI_MEMORY_NVS:
 323                         e820_type = E820_NVS;
 324                         break;
 325                 case EFI_UNUSABLE_MEMORY:
 326                         e820_type = E820_UNUSABLE;
 327                         break;
 328                 default:
 329                         /*
 330                          * EFI_RESERVED_TYPE EFI_RUNTIME_SERVICES_CODE
 331                          * EFI_RUNTIME_SERVICES_DATA EFI_MEMORY_MAPPED_IO
 332                          * EFI_MEMORY_MAPPED_IO_PORT_SPACE EFI_PAL_CODE
 333                          */
 334                         e820_type = E820_RESERVED;
 335                         break;
 336                 }
 337                 e820_add_region(start, size, e820_type);
 338         }
 339         sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
 340 }
 341
 342 void __init efi_memblock_x86_reserve_range(void)
 343 {
 344         unsigned long pmap;
 345
 346 #ifdef CONFIG_X86_32
 347         pmap = boot_params.efi_info.efi_memmap;
 348 #else
 349         pmap = (boot_params.efi_info.efi_memmap |
 350                 ((__u64)boot_params.efi_info.efi_memmap_hi<<32));
 351 #endif
 352         memmap.phys_map = (void *)pmap;
 353         memmap.nr_map = boot_params.efi_info.efi_memmap_size /
 354                 boot_params.efi_info.efi_memdesc_size;
 355         memmap.desc_version = boot_params.efi_info.efi_memdesc_version;
 356         memmap.desc_size = boot_params.efi_info.efi_memdesc_size;
 357         memblock_reserve(pmap, memmap.nr_map * memmap.desc_size);
 358 }
 359
 360 #if EFI_DEBUG
 361 static void __init print_efi_memmap(void)
 362 {
 363         efi_memory_desc_t *md;
 364         void *p;
 365         int i;
 366
 367         for (p = memmap.map, i = 0;
 368              p < memmap.map_end;
 369              p += memmap.desc_size, i++) {
 370                 md = p;
 371                 pr_info("mem%02u: type=%u, attr=0x%llx, "
 372                         "range=[0x%016llx-0x%016llx) (%lluMB)\n",
 373                         i, md->type, md->attribute, md->phys_addr,
 374                         md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT),
 375                         (md->num_pages >> (20 - EFI_PAGE_SHIFT)));
 376         }
 377 }
 378 #endif  /*  EFI_DEBUG  */
 379
 380 void __init efi_reserve_boot_services(void)
 381 {
 382         void *p;
 383
 384         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 385                 efi_memory_desc_t *md = p;
 386                 u64 start = md->phys_addr;
 387                 u64 size = md->num_pages << EFI_PAGE_SHIFT;
 388
 389                 if (md->type != EFI_BOOT_SERVICES_CODE &&
 390                     md->type != EFI_BOOT_SERVICES_DATA)
 391                         continue;
 392                 /* Only reserve where possible:
 393                  * - Not within any already allocated areas
 394                  * - Not over any memory area (really needed, if above?)
 395                  * - Not within any part of the kernel
 396                  * - Not the bios reserved area
 397                 */
 398                 if ((start+size >= virt_to_phys(_text)
 399                                 && start <= virt_to_phys(_end)) ||
 400                         !e820_all_mapped(start, start+size, E820_RAM) ||
 401                         memblock_is_region_reserved(start, size)) {
 402                         /* Could not reserve, skip it */
 403                         md->num_pages = 0;
 404                         memblock_dbg("Could not reserve boot range "
 405                                         "[0x%010llx-0x%010llx]\n",
 406                                                 start, start+size-1);
 407                 } else
 408                         memblock_reserve(start, size);
 409         }
 410 }
 411
 412 static void __init efi_free_boot_services(void)
 413 {
 414         void *p;
 415
 416         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 417                 efi_memory_desc_t *md = p;
 418                 unsigned long long start = md->phys_addr;
 419                 unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
 420
 421                 if (md->type != EFI_BOOT_SERVICES_CODE &&
 422                     md->type != EFI_BOOT_SERVICES_DATA)
 423                         continue;
 424
 425                 /* Could not reserve boot area */
 426                 if (!size)
 427                         continue;
 428
 429                 free_bootmem_late(start, size);
 430         }
 431 }
 432
 433 static void __init efi_systab_init(void *phys)
 434 {
 435         efi.systab = early_ioremap((unsigned long)efi_phys.systab,
 436                                    sizeof(efi_system_table_t));
 437         if (efi.systab == NULL)
 438                 pr_err("Couldn't map the system table!\n");
 439         memcpy(&efi_systab, efi.systab, sizeof(efi_system_table_t));
 440         early_iounmap(efi.systab, sizeof(efi_system_table_t));
 441         efi.systab = &efi_systab;
 442
 443         /*
 444          * Verify the EFI Table
 445          */
 446         if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 447                 pr_err("System table signature incorrect!\n");
 448         if ((efi.systab->hdr.revision >> 16) == 0)
 449                 pr_err("Warning: System table version "
 450                        "%d.%02d, expected 1.00 or greater!\n",
 451                        efi.systab->hdr.revision >> 16,
 452                        efi.systab->hdr.revision & 0xffff);
 453 }
 454
 455 static void __init efi_config_init(u64 tables, int nr_tables)
 456 {
 457         efi_config_table_t *config_tables;
 458         int i;
 459
 460         /*
 461          * Let's see what config tables the firmware passed to us.
 462          */
 463         config_tables = early_ioremap(
 464                 efi.systab->tables,
 465                 efi.systab->nr_tables * sizeof(efi_config_table_t));
 466         if (config_tables == NULL)
 467                 pr_err("Could not map Configuration table!\n");
 468
 469         pr_info("");
 470         for (i = 0; i < efi.systab->nr_tables; i++) {
 471                 if (!efi_guidcmp(config_tables[i].guid, MPS_TABLE_GUID)) {
 472                         efi.mps = config_tables[i].table;
 473                         pr_cont(" MPS=0x%lx ", config_tables[i].table);
 474                 } else if (!efi_guidcmp(config_tables[i].guid,
 475                                         ACPI_20_TABLE_GUID)) {
 476                         efi.acpi20 = config_tables[i].table;
 477                         pr_cont(" ACPI 2.0=0x%lx ", config_tables[i].table);
 478                 } else if (!efi_guidcmp(config_tables[i].guid,
 479                                         ACPI_TABLE_GUID)) {
 480                         efi.acpi = config_tables[i].table;
 481                         pr_cont(" ACPI=0x%lx ", config_tables[i].table);
 482                 } else if (!efi_guidcmp(config_tables[i].guid,
 483                                         SMBIOS_TABLE_GUID)) {
 484                         efi.smbios = config_tables[i].table;
 485                         pr_cont(" SMBIOS=0x%lx ", config_tables[i].table);
 486 #ifdef CONFIG_X86_UV
 487                 } else if (!efi_guidcmp(config_tables[i].guid,
 488                                         UV_SYSTEM_TABLE_GUID)) {
 489                         efi.uv_systab = config_tables[i].table;
 490                         pr_cont(" UVsystab=0x%lx ", config_tables[i].table);
 491 #endif
 492                 } else if (!efi_guidcmp(config_tables[i].guid,
 493                                         HCDP_TABLE_GUID)) {
 494                         efi.hcdp = config_tables[i].table;
 495                         pr_cont(" HCDP=0x%lx ", config_tables[i].table);
 496                 } else if (!efi_guidcmp(config_tables[i].guid,
 497                                         UGA_IO_PROTOCOL_GUID)) {
 498                         efi.uga = config_tables[i].table;
 499                         pr_cont(" UGA=0x%lx ", config_tables[i].table);
 500                 }
 501         }
 502         pr_cont("\n");
 503         early_iounmap(config_tables,
 504                           efi.systab->nr_tables * sizeof(efi_config_table_t));
 505 }
 506
 507 static void __init efi_runtime_init(void)
 508 {
 509         efi_runtime_services_t *runtime;
 510
 511         /*
 512          * Check out the runtime services table. We need to map
 513          * the runtime services table so that we can grab the physical
 514          * address of several of the EFI runtime functions, needed to
 515          * set the firmware into virtual mode.
 516          */
 517         runtime = early_ioremap((unsigned long)efi.systab->runtime,
 518                                 sizeof(efi_runtime_services_t));
 519         if (runtime != NULL) {
 520                 /*
 521                  * We will only need *early* access to the following
 522                  * two EFI runtime services before set_virtual_address_map
 523                  * is invoked.
 524                  */
 525                 efi_phys.get_time = (efi_get_time_t *)runtime->get_time;
 526                 efi_phys.set_virtual_address_map =
 527                         (efi_set_virtual_address_map_t *)
 528                         runtime->set_virtual_address_map;
 529                 /*
 530                  * Make efi_get_time can be called before entering
 531                  * virtual mode.
 532                  */
 533                 efi.get_time = phys_efi_get_time;
 534         } else
 535                 pr_err("Could not map the runtime service table!\n");
 536         early_iounmap(runtime, sizeof(efi_runtime_services_t));
 537 }
 538
 539 static void __init efi_memmap_init(void)
 540 {
 541         /* Map the EFI memory map */
 542         memmap.map = early_ioremap((unsigned long)memmap.phys_map,
 543                                    memmap.nr_map * memmap.desc_size);
 544         if (memmap.map == NULL)
 545                 pr_err("Could not map the memory map!\n");
 546         memmap.map_end = memmap.map + (memmap.nr_map * memmap.desc_size);
 547
 548         if (add_efi_memmap)
 549                 do_add_efi_memmap();
 550 }
 551
 552 void __init efi_init(void)
 553 {
 554         efi_char16_t *c16;
 555         char vendor[100] = "unknown";
 556         int i = 0;
 557         void *tmp;
 558
 559 #ifdef CONFIG_X86_32
 560         efi_phys.systab = (efi_system_table_t *)boot_params.efi_info.efi_systab;
 561 #else
 562         efi_phys.systab = (efi_system_table_t *)
 563                 (boot_params.efi_info.efi_systab |
 564                  ((__u64)boot_params.efi_info.efi_systab_hi<<32));
 565 #endif
 566
 567         efi_systab_init(efi_phys.systab);
 568
 569         /*
 570          * Show what we know for posterity
 571          */
 572         c16 = tmp = early_ioremap(efi.systab->fw_vendor, 2);
 573         if (c16) {
 574                 for (i = 0; i < sizeof(vendor) - 1 && *c16; ++i)
 575                         vendor[i] = *c16++;
 576                 vendor[i] = '\0';
 577         } else
 578                 pr_err("Could not map the firmware vendor!\n");
 579         early_iounmap(tmp, 2);
 580
 581         pr_info("EFI v%u.%.02u by %s\n",
 582                 efi.systab->hdr.revision >> 16,
 583                 efi.systab->hdr.revision & 0xffff, vendor);
 584
 585         efi_config_init(efi.systab->tables, efi.systab->nr_tables);
 586
 587         efi_runtime_init();
 588
 589         efi_memmap_init();
 590
 591 #ifdef CONFIG_X86_32
 592         x86_platform.get_wallclock = efi_get_time;
 593         x86_platform.set_wallclock = efi_set_rtc_mmss;
 594 #endif
 595
 596 #if EFI_DEBUG
 597         print_efi_memmap();
 598 #endif
 599 }
 600
 601 void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
 602 {
 603         u64 addr, npages;
 604
 605         addr = md->virt_addr;
 606         npages = md->num_pages;
 607
 608         memrange_efi_to_native(&addr, &npages);
 609
 610         if (executable)
 611                 set_memory_x(addr, npages);
 612         else
 613                 set_memory_nx(addr, npages);
 614 }
 615
 616 static void __init runtime_code_page_mkexec(void)
 617 {
 618         efi_memory_desc_t *md;
 619         void *p;
 620
 621         /* Make EFI runtime service code area executable */
 622         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 623                 md = p;
 624
 625                 if (md->type != EFI_RUNTIME_SERVICES_CODE)
 626                         continue;
 627
 628                 efi_set_executable(md, true);
 629         }
 630 }
 631
 632 /*
 633  * This function will switch the EFI runtime services to virtual mode.
 634  * Essentially, look through the EFI memmap and map every region that
 635  * has the runtime attribute bit set in its memory descriptor and update
 636  * that memory descriptor with the virtual address obtained from ioremap().
 637  * This enables the runtime services to be called without having to
 638  * thunk back into physical mode for every invocation.
 639  */
 640 void __init efi_enter_virtual_mode(void)
 641 {
 642         efi_memory_desc_t *md, *prev_md = NULL;
 643         efi_status_t status;
 644         unsigned long size;
 645         u64 end, systab, addr, npages, end_pfn;
 646         void *p, *va, *new_memmap = NULL;
 647         int count = 0;
 648
 649         efi.systab = NULL;
 650
 651         /* Merge contiguous regions of the same type and attribute */
 652         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 653                 u64 prev_size;
 654                 md = p;
 655
 656                 if (!prev_md) {
 657                         prev_md = md;
 658                         continue;
 659                 }
 660
 661                 if (prev_md->type != md->type ||
 662                     prev_md->attribute != md->attribute) {
 663                         prev_md = md;
 664                         continue;
 665                 }
 666
 667                 prev_size = prev_md->num_pages << EFI_PAGE_SHIFT;
 668
 669                 if (md->phys_addr == (prev_md->phys_addr + prev_size)) {
 670                         prev_md->num_pages += md->num_pages;
 671                         md->type = EFI_RESERVED_TYPE;
 672                         md->attribute = 0;
 673                         continue;
 674                 }
 675                 prev_md = md;
 676         }
 677
 678         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 679                 md = p;
 680                 if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
 681                     md->type != EFI_BOOT_SERVICES_CODE &&
 682                     md->type != EFI_BOOT_SERVICES_DATA)
 683                         continue;
 684
 685                 size = md->num_pages << EFI_PAGE_SHIFT;
 686                 end = md->phys_addr + size;
 687
 688                 end_pfn = PFN_UP(end);
 689                 if (end_pfn <= max_low_pfn_mapped
 690                     || (end_pfn > (1UL << (32 - PAGE_SHIFT))
 691                         && end_pfn <= max_pfn_mapped))
 692                         va = __va(md->phys_addr);
 693                 else
 694                         va = efi_ioremap(md->phys_addr, size, md->type);
 695
 696                 md->virt_addr = (u64) (unsigned long) va;
 697
 698                 if (!va) {
 699                         pr_err("ioremap of 0x%llX failed!\n",
 700                                (unsigned long long)md->phys_addr);
 701                         continue;
 702                 }
 703
 704                 if (!(md->attribute & EFI_MEMORY_WB)) {
 705                         addr = md->virt_addr;
 706                         npages = md->num_pages;
 707                         memrange_efi_to_native(&addr, &npages);
 708                         set_memory_uc(addr, npages);
 709                 }
 710
 711                 systab = (u64) (unsigned long) efi_phys.systab;
 712                 if (md->phys_addr <= systab && systab < end) {
 713                         systab += md->virt_addr - md->phys_addr;
 714                         efi.systab = (efi_system_table_t *) (unsigned long) systab;
 715                 }
 716                 new_memmap = krealloc(new_memmap,
 717                                       (count + 1) * memmap.desc_size,
 718                                       GFP_KERNEL);
 719                 memcpy(new_memmap + (count * memmap.desc_size), md,
 720                        memmap.desc_size);
 721                 count++;
 722         }
 723
 724         BUG_ON(!efi.systab);
 725
 726         status = phys_efi_set_virtual_address_map(
 727                 memmap.desc_size * count,
 728                 memmap.desc_size,
 729                 memmap.desc_version,
 730                 (efi_memory_desc_t *)__pa(new_memmap));
 731
 732         if (status != EFI_SUCCESS) {
 733                 pr_alert("Unable to switch EFI into virtual mode "
 734                          "(status=%lx)!\n", status);
 735                 panic("EFI call to SetVirtualAddressMap() failed!");
 736         }
 737
 738         /*
 739          * Thankfully, it does seem that no runtime services other than
 740          * SetVirtualAddressMap() will touch boot services code, so we can
 741          * get rid of it all at this point
 742          */
 743         efi_free_boot_services();
 744
 745         /*
 746          * Now that EFI is in virtual mode, update the function
 747          * pointers in the runtime service table to the new virtual addresses.
 748          *
 749          * Call EFI services through wrapper functions.
 750          */
 751         efi.get_time = virt_efi_get_time;
 752         efi.set_time = virt_efi_set_time;
 753         efi.get_wakeup_time = virt_efi_get_wakeup_time;
 754         efi.set_wakeup_time = virt_efi_set_wakeup_time;
 755         efi.get_variable = virt_efi_get_variable;
 756         efi.get_next_variable = virt_efi_get_next_variable;
 757         efi.set_variable = virt_efi_set_variable;
 758         efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count;
 759         efi.reset_system = virt_efi_reset_system;
 760         efi.set_virtual_address_map = NULL;
 761         efi.query_variable_info = virt_efi_query_variable_info;
 762         efi.update_capsule = virt_efi_update_capsule;
 763         efi.query_capsule_caps = virt_efi_query_capsule_caps;
 764         if (__supported_pte_mask & _PAGE_NX)
 765                 runtime_code_page_mkexec();
 766         early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size);
 767         memmap.map = NULL;
 768         kfree(new_memmap);
 769 }
 770
 771 /*
 772  * Convenience functions to obtain memory types and attributes
 773  */
 774 u32 efi_mem_type(unsigned long phys_addr)
 775 {
 776         efi_memory_desc_t *md;
 777         void *p;
 778
 779         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 780                 md = p;
 781                 if ((md->phys_addr <= phys_addr) &&
 782                     (phys_addr < (md->phys_addr +
 783                                   (md->num_pages << EFI_PAGE_SHIFT))))
 784                         return md->type;
 785         }
 786         return 0;
 787 }
 788
 789 u64 efi_mem_attributes(unsigned long phys_addr)
 790 {
 791         efi_memory_desc_t *md;
 792         void *p;
 793
 794         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 795                 md = p;
 796                 if ((md->phys_addr <= phys_addr) &&
 797                     (phys_addr < (md->phys_addr +
 798                                   (md->num_pages << EFI_PAGE_SHIFT))))
 799                         return md->attribute;
 800         }
 801         return 0;
 802 }