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 <[email protected]>
   7  * Copyright (C) 1999-2002 Hewlett-Packard Co.
   8  *      David Mosberger-Tang <[email protected]>
   9  *      Stephane Eranian <[email protected]>
  10  * Copyright (C) 2005-2008 Intel Co.
  11  *      Fenghua Yu <[email protected]>
  12  *      Bibo Mao <[email protected]>
  13  *      Chandramouli Narayanan <[email protected]>
  14  *      Huang Ying <[email protected]>
  15  * Copyright (C) 2013 SuSE Labs
  16  *      Borislav Petkov <[email protected]> - runtime services VA mapping
  17  *
  18  * Copied from efi_32.c to eliminate the duplicated code between EFI
  19  * 32/64 support code. --ying 2007-10-26
  20  *
  21  * All EFI Runtime Services are not implemented yet as EFI only
  22  * supports physical mode addressing on SoftSDV. This is to be fixed
  23  * in a future version.  --drummond 1999-07-20
  24  *
  25  * Implemented EFI runtime services and virtual mode calls.  --davidm
  26  *
  27  * Goutham Rao: <[email protected]>
  28  *      Skip non-WB memory and ignore empty memory ranges.
  29  */
  30
  31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  32
  33 #include <linux/kernel.h>
  34 #include <linux/init.h>
  35 #include <linux/efi.h>
  36 #include <linux/efi-bgrt.h>
  37 #include <linux/export.h>
  38 #include <linux/bootmem.h>
  39 #include <linux/slab.h>
  40 #include <linux/memblock.h>
  41 #include <linux/spinlock.h>
  42 #include <linux/uaccess.h>
  43 #include <linux/time.h>
  44 #include <linux/io.h>
  45 #include <linux/reboot.h>
  46 #include <linux/bcd.h>
  47
  48 #include <asm/setup.h>
  49 #include <asm/efi.h>
  50 #include <asm/time.h>
  51 #include <asm/cacheflush.h>
  52 #include <asm/tlbflush.h>
  53 #include <asm/x86_init.h>
  54 #include <asm/rtc.h>
  55 #include <asm/uv/uv.h>
  56
  57 #define EFI_DEBUG
  58
  59 struct efi_memory_map memmap;
  60
  61 static struct efi efi_phys __initdata;
  62 static efi_system_table_t efi_systab __initdata;
  63
  64 static efi_config_table_type_t arch_tables[] __initdata = {
  65 #ifdef CONFIG_X86_UV
  66         {UV_SYSTEM_TABLE_GUID, "UVsystab", &efi.uv_systab},
  67 #endif
  68         {NULL_GUID, NULL, NULL},
  69 };
  70
  71 u64 efi_setup;          /* efi setup_data physical address */
  72
  73 static int add_efi_memmap __initdata;
  74 static int __init setup_add_efi_memmap(char *arg)
  75 {
  76         add_efi_memmap = 1;
  77         return 0;
  78 }
  79 early_param("add_efi_memmap", setup_add_efi_memmap);
  80
  81 static efi_status_t __init phys_efi_set_virtual_address_map(
  82         unsigned long memory_map_size,
  83         unsigned long descriptor_size,
  84         u32 descriptor_version,
  85         efi_memory_desc_t *virtual_map)
  86 {
  87         efi_status_t status;
  88
  89         efi_call_phys_prolog();
  90         status = efi_call_phys(efi_phys.set_virtual_address_map,
  91                                memory_map_size, descriptor_size,
  92                                descriptor_version, virtual_map);
  93         efi_call_phys_epilog();
  94         return status;
  95 }
  96
  97 void efi_get_time(struct timespec *now)
  98 {
  99         efi_status_t status;
 100         efi_time_t eft;
 101         efi_time_cap_t cap;
 102
 103         status = efi.get_time(&eft, &cap);
 104         if (status != EFI_SUCCESS)
 105                 pr_err("Oops: efitime: can't read time!\n");
 106
 107         now->tv_sec = mktime(eft.year, eft.month, eft.day, eft.hour,
 108                              eft.minute, eft.second);
 109         now->tv_nsec = 0;
 110 }
 111
 112 /*
 113  * Tell the kernel about the EFI memory map.  This might include
 114  * more than the max 128 entries that can fit in the e820 legacy
 115  * (zeropage) memory map.
 116  */
 117
 118 static void __init do_add_efi_memmap(void)
 119 {
 120         void *p;
 121
 122         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 123                 efi_memory_desc_t *md = p;
 124                 unsigned long long start = md->phys_addr;
 125                 unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
 126                 int e820_type;
 127
 128                 switch (md->type) {
 129                 case EFI_LOADER_CODE:
 130                 case EFI_LOADER_DATA:
 131                 case EFI_BOOT_SERVICES_CODE:
 132                 case EFI_BOOT_SERVICES_DATA:
 133                 case EFI_CONVENTIONAL_MEMORY:
 134                         if (md->attribute & EFI_MEMORY_WB)
 135                                 e820_type = E820_RAM;
 136                         else
 137                                 e820_type = E820_RESERVED;
 138                         break;
 139                 case EFI_ACPI_RECLAIM_MEMORY:
 140                         e820_type = E820_ACPI;
 141                         break;
 142                 case EFI_ACPI_MEMORY_NVS:
 143                         e820_type = E820_NVS;
 144                         break;
 145                 case EFI_UNUSABLE_MEMORY:
 146                         e820_type = E820_UNUSABLE;
 147                         break;
 148                 default:
 149                         /*
 150                          * EFI_RESERVED_TYPE EFI_RUNTIME_SERVICES_CODE
 151                          * EFI_RUNTIME_SERVICES_DATA EFI_MEMORY_MAPPED_IO
 152                          * EFI_MEMORY_MAPPED_IO_PORT_SPACE EFI_PAL_CODE
 153                          */
 154                         e820_type = E820_RESERVED;
 155                         break;
 156                 }
 157                 e820_add_region(start, size, e820_type);
 158         }
 159         sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
 160 }
 161
 162 int __init efi_memblock_x86_reserve_range(void)
 163 {
 164         struct efi_info *e = &boot_params.efi_info;
 165         unsigned long pmap;
 166
 167         if (efi_enabled(EFI_PARAVIRT))
 168                 return 0;
 169
 170 #ifdef CONFIG_X86_32
 171         /* Can't handle data above 4GB at this time */
 172         if (e->efi_memmap_hi) {
 173                 pr_err("Memory map is above 4GB, disabling EFI.\n");
 174                 return -EINVAL;
 175         }
 176         pmap =  e->efi_memmap;
 177 #else
 178         pmap = (e->efi_memmap | ((__u64)e->efi_memmap_hi << 32));
 179 #endif
 180         memmap.phys_map         = (void *)pmap;
 181         memmap.nr_map           = e->efi_memmap_size /
 182                                   e->efi_memdesc_size;
 183         memmap.desc_size        = e->efi_memdesc_size;
 184         memmap.desc_version     = e->efi_memdesc_version;
 185
 186         memblock_reserve(pmap, memmap.nr_map * memmap.desc_size);
 187
 188         efi.memmap = &memmap;
 189
 190         return 0;
 191 }
 192
 193 static void __init print_efi_memmap(void)
 194 {
 195 #ifdef EFI_DEBUG
 196         efi_memory_desc_t *md;
 197         void *p;
 198         int i;
 199
 200         for (p = memmap.map, i = 0;
 201              p < memmap.map_end;
 202              p += memmap.desc_size, i++) {
 203                 char buf[64];
 204
 205                 md = p;
 206                 pr_info("mem%02u: %s range=[0x%016llx-0x%016llx) (%lluMB)\n",
 207                         i, efi_md_typeattr_format(buf, sizeof(buf), md),
 208                         md->phys_addr,
 209                         md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT),
 210                         (md->num_pages >> (20 - EFI_PAGE_SHIFT)));
 211         }
 212 #endif  /*  EFI_DEBUG  */
 213 }
 214
 215 void __init efi_unmap_memmap(void)
 216 {
 217         clear_bit(EFI_MEMMAP, &efi.flags);
 218         if (memmap.map) {
 219                 early_memunmap(memmap.map, memmap.nr_map * memmap.desc_size);
 220                 memmap.map = NULL;
 221         }
 222 }
 223
 224 static int __init efi_systab_init(void *phys)
 225 {
 226         if (efi_enabled(EFI_64BIT)) {
 227                 efi_system_table_64_t *systab64;
 228                 struct efi_setup_data *data = NULL;
 229                 u64 tmp = 0;
 230
 231                 if (efi_setup) {
 232                         data = early_memremap(efi_setup, sizeof(*data));
 233                         if (!data)
 234                                 return -ENOMEM;
 235                 }
 236                 systab64 = early_memremap((unsigned long)phys,
 237                                          sizeof(*systab64));
 238                 if (systab64 == NULL) {
 239                         pr_err("Couldn't map the system table!\n");
 240                         if (data)
 241                                 early_memunmap(data, sizeof(*data));
 242                         return -ENOMEM;
 243                 }
 244
 245                 efi_systab.hdr = systab64->hdr;
 246                 efi_systab.fw_vendor = data ? (unsigned long)data->fw_vendor :
 247                                               systab64->fw_vendor;
 248                 tmp |= data ? data->fw_vendor : systab64->fw_vendor;
 249                 efi_systab.fw_revision = systab64->fw_revision;
 250                 efi_systab.con_in_handle = systab64->con_in_handle;
 251                 tmp |= systab64->con_in_handle;
 252                 efi_systab.con_in = systab64->con_in;
 253                 tmp |= systab64->con_in;
 254                 efi_systab.con_out_handle = systab64->con_out_handle;
 255                 tmp |= systab64->con_out_handle;
 256                 efi_systab.con_out = systab64->con_out;
 257                 tmp |= systab64->con_out;
 258                 efi_systab.stderr_handle = systab64->stderr_handle;
 259                 tmp |= systab64->stderr_handle;
 260                 efi_systab.stderr = systab64->stderr;
 261                 tmp |= systab64->stderr;
 262                 efi_systab.runtime = data ?
 263                                      (void *)(unsigned long)data->runtime :
 264                                      (void *)(unsigned long)systab64->runtime;
 265                 tmp |= data ? data->runtime : systab64->runtime;
 266                 efi_systab.boottime = (void *)(unsigned long)systab64->boottime;
 267                 tmp |= systab64->boottime;
 268                 efi_systab.nr_tables = systab64->nr_tables;
 269                 efi_systab.tables = data ? (unsigned long)data->tables :
 270                                            systab64->tables;
 271                 tmp |= data ? data->tables : systab64->tables;
 272
 273                 early_memunmap(systab64, sizeof(*systab64));
 274                 if (data)
 275                         early_memunmap(data, sizeof(*data));
 276 #ifdef CONFIG_X86_32
 277                 if (tmp >> 32) {
 278                         pr_err("EFI data located above 4GB, disabling EFI.\n");
 279                         return -EINVAL;
 280                 }
 281 #endif
 282         } else {
 283                 efi_system_table_32_t *systab32;
 284
 285                 systab32 = early_memremap((unsigned long)phys,
 286                                          sizeof(*systab32));
 287                 if (systab32 == NULL) {
 288                         pr_err("Couldn't map the system table!\n");
 289                         return -ENOMEM;
 290                 }
 291
 292                 efi_systab.hdr = systab32->hdr;
 293                 efi_systab.fw_vendor = systab32->fw_vendor;
 294                 efi_systab.fw_revision = systab32->fw_revision;
 295                 efi_systab.con_in_handle = systab32->con_in_handle;
 296                 efi_systab.con_in = systab32->con_in;
 297                 efi_systab.con_out_handle = systab32->con_out_handle;
 298                 efi_systab.con_out = systab32->con_out;
 299                 efi_systab.stderr_handle = systab32->stderr_handle;
 300                 efi_systab.stderr = systab32->stderr;
 301                 efi_systab.runtime = (void *)(unsigned long)systab32->runtime;
 302                 efi_systab.boottime = (void *)(unsigned long)systab32->boottime;
 303                 efi_systab.nr_tables = systab32->nr_tables;
 304                 efi_systab.tables = systab32->tables;
 305
 306                 early_memunmap(systab32, sizeof(*systab32));
 307         }
 308
 309         efi.systab = &efi_systab;
 310
 311         /*
 312          * Verify the EFI Table
 313          */
 314         if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
 315                 pr_err("System table signature incorrect!\n");
 316                 return -EINVAL;
 317         }
 318         if ((efi.systab->hdr.revision >> 16) == 0)
 319                 pr_err("Warning: System table version %d.%02d, expected 1.00 or greater!\n",
 320                        efi.systab->hdr.revision >> 16,
 321                        efi.systab->hdr.revision & 0xffff);
 322
 323         set_bit(EFI_SYSTEM_TABLES, &efi.flags);
 324
 325         return 0;
 326 }
 327
 328 static int __init efi_runtime_init32(void)
 329 {
 330         efi_runtime_services_32_t *runtime;
 331
 332         runtime = early_memremap((unsigned long)efi.systab->runtime,
 333                         sizeof(efi_runtime_services_32_t));
 334         if (!runtime) {
 335                 pr_err("Could not map the runtime service table!\n");
 336                 return -ENOMEM;
 337         }
 338
 339         /*
 340          * We will only need *early* access to the SetVirtualAddressMap
 341          * EFI runtime service. All other runtime services will be called
 342          * via the virtual mapping.
 343          */
 344         efi_phys.set_virtual_address_map =
 345                         (efi_set_virtual_address_map_t *)
 346                         (unsigned long)runtime->set_virtual_address_map;
 347         early_memunmap(runtime, sizeof(efi_runtime_services_32_t));
 348
 349         return 0;
 350 }
 351
 352 static int __init efi_runtime_init64(void)
 353 {
 354         efi_runtime_services_64_t *runtime;
 355
 356         runtime = early_memremap((unsigned long)efi.systab->runtime,
 357                         sizeof(efi_runtime_services_64_t));
 358         if (!runtime) {
 359                 pr_err("Could not map the runtime service table!\n");
 360                 return -ENOMEM;
 361         }
 362
 363         /*
 364          * We will only need *early* access to the SetVirtualAddressMap
 365          * EFI runtime service. All other runtime services will be called
 366          * via the virtual mapping.
 367          */
 368         efi_phys.set_virtual_address_map =
 369                         (efi_set_virtual_address_map_t *)
 370                         (unsigned long)runtime->set_virtual_address_map;
 371         early_memunmap(runtime, sizeof(efi_runtime_services_64_t));
 372
 373         return 0;
 374 }
 375
 376 static int __init efi_runtime_init(void)
 377 {
 378         int rv;
 379
 380         /*
 381          * Check out the runtime services table. We need to map
 382          * the runtime services table so that we can grab the physical
 383          * address of several of the EFI runtime functions, needed to
 384          * set the firmware into virtual mode.
 385          *
 386          * When EFI_PARAVIRT is in force then we could not map runtime
 387          * service memory region because we do not have direct access to it.
 388          * However, runtime services are available through proxy functions
 389          * (e.g. in case of Xen dom0 EFI implementation they call special
 390          * hypercall which executes relevant EFI functions) and that is why
 391          * they are always enabled.
 392          */
 393
 394         if (!efi_enabled(EFI_PARAVIRT)) {
 395                 if (efi_enabled(EFI_64BIT))
 396                         rv = efi_runtime_init64();
 397                 else
 398                         rv = efi_runtime_init32();
 399
 400                 if (rv)
 401                         return rv;
 402         }
 403
 404         set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 405
 406         return 0;
 407 }
 408
 409 static int __init efi_memmap_init(void)
 410 {
 411         if (efi_enabled(EFI_PARAVIRT))
 412                 return 0;
 413
 414         /* Map the EFI memory map */
 415         memmap.map = early_memremap((unsigned long)memmap.phys_map,
 416                                    memmap.nr_map * memmap.desc_size);
 417         if (memmap.map == NULL) {
 418                 pr_err("Could not map the memory map!\n");
 419                 return -ENOMEM;
 420         }
 421         memmap.map_end = memmap.map + (memmap.nr_map * memmap.desc_size);
 422
 423         if (add_efi_memmap)
 424                 do_add_efi_memmap();
 425
 426         set_bit(EFI_MEMMAP, &efi.flags);
 427
 428         return 0;
 429 }
 430
 431 void __init efi_init(void)
 432 {
 433         efi_char16_t *c16;
 434         char vendor[100] = "unknown";
 435         int i = 0;
 436         void *tmp;
 437
 438 #ifdef CONFIG_X86_32
 439         if (boot_params.efi_info.efi_systab_hi ||
 440             boot_params.efi_info.efi_memmap_hi) {
 441                 pr_info("Table located above 4GB, disabling EFI.\n");
 442                 return;
 443         }
 444         efi_phys.systab = (efi_system_table_t *)boot_params.efi_info.efi_systab;
 445 #else
 446         efi_phys.systab = (efi_system_table_t *)
 447                           (boot_params.efi_info.efi_systab |
 448                           ((__u64)boot_params.efi_info.efi_systab_hi<<32));
 449 #endif
 450
 451         if (efi_systab_init(efi_phys.systab))
 452                 return;
 453
 454         efi.config_table = (unsigned long)efi.systab->tables;
 455         efi.fw_vendor    = (unsigned long)efi.systab->fw_vendor;
 456         efi.runtime      = (unsigned long)efi.systab->runtime;
 457
 458         /*
 459          * Show what we know for posterity
 460          */
 461         c16 = tmp = early_memremap(efi.systab->fw_vendor, 2);
 462         if (c16) {
 463                 for (i = 0; i < sizeof(vendor) - 1 && *c16; ++i)
 464                         vendor[i] = *c16++;
 465                 vendor[i] = '\0';
 466         } else
 467                 pr_err("Could not map the firmware vendor!\n");
 468         early_memunmap(tmp, 2);
 469
 470         pr_info("EFI v%u.%.02u by %s\n",
 471                 efi.systab->hdr.revision >> 16,
 472                 efi.systab->hdr.revision & 0xffff, vendor);
 473
 474         if (efi_reuse_config(efi.systab->tables, efi.systab->nr_tables))
 475                 return;
 476
 477         if (efi_config_init(arch_tables))
 478                 return;
 479
 480         /*
 481          * Note: We currently don't support runtime services on an EFI
 482          * that doesn't match the kernel 32/64-bit mode.
 483          */
 484
 485         if (!efi_runtime_supported())
 486                 pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n");
 487         else {
 488                 if (efi_runtime_disabled() || efi_runtime_init())
 489                         return;
 490         }
 491         if (efi_memmap_init())
 492                 return;
 493
 494         print_efi_memmap();
 495 }
 496
 497 void __init efi_late_init(void)
 498 {
 499         efi_bgrt_init();
 500 }
 501
 502 void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
 503 {
 504         u64 addr, npages;
 505
 506         addr = md->virt_addr;
 507         npages = md->num_pages;
 508
 509         memrange_efi_to_native(&addr, &npages);
 510
 511         if (executable)
 512                 set_memory_x(addr, npages);
 513         else
 514                 set_memory_nx(addr, npages);
 515 }
 516
 517 void __init runtime_code_page_mkexec(void)
 518 {
 519         efi_memory_desc_t *md;
 520         void *p;
 521
 522         /* Make EFI runtime service code area executable */
 523         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 524                 md = p;
 525
 526                 if (md->type != EFI_RUNTIME_SERVICES_CODE)
 527                         continue;
 528
 529                 efi_set_executable(md, true);
 530         }
 531 }
 532
 533 void __init efi_memory_uc(u64 addr, unsigned long size)
 534 {
 535         unsigned long page_shift = 1UL << EFI_PAGE_SHIFT;
 536         u64 npages;
 537
 538         npages = round_up(size, page_shift) / page_shift;
 539         memrange_efi_to_native(&addr, &npages);
 540         set_memory_uc(addr, npages);
 541 }
 542
 543 void __init old_map_region(efi_memory_desc_t *md)
 544 {
 545         u64 start_pfn, end_pfn, end;
 546         unsigned long size;
 547         void *va;
 548
 549         start_pfn = PFN_DOWN(md->phys_addr);
 550         size      = md->num_pages << PAGE_SHIFT;
 551         end       = md->phys_addr + size;
 552         end_pfn   = PFN_UP(end);
 553
 554         if (pfn_range_is_mapped(start_pfn, end_pfn)) {
 555                 va = __va(md->phys_addr);
 556
 557                 if (!(md->attribute & EFI_MEMORY_WB))
 558                         efi_memory_uc((u64)(unsigned long)va, size);
 559         } else
 560                 va = efi_ioremap(md->phys_addr, size,
 561                                  md->type, md->attribute);
 562
 563         md->virt_addr = (u64) (unsigned long) va;
 564         if (!va)
 565                 pr_err("ioremap of 0x%llX failed!\n",
 566                        (unsigned long long)md->phys_addr);
 567 }
 568
 569 /* Merge contiguous regions of the same type and attribute */
 570 static void __init efi_merge_regions(void)
 571 {
 572         void *p;
 573         efi_memory_desc_t *md, *prev_md = NULL;
 574
 575         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 576                 u64 prev_size;
 577                 md = p;
 578
 579                 if (!prev_md) {
 580                         prev_md = md;
 581                         continue;
 582                 }
 583
 584                 if (prev_md->type != md->type ||
 585                     prev_md->attribute != md->attribute) {
 586                         prev_md = md;
 587                         continue;
 588                 }
 589
 590                 prev_size = prev_md->num_pages << EFI_PAGE_SHIFT;
 591
 592                 if (md->phys_addr == (prev_md->phys_addr + prev_size)) {
 593                         prev_md->num_pages += md->num_pages;
 594                         md->type = EFI_RESERVED_TYPE;
 595                         md->attribute = 0;
 596                         continue;
 597                 }
 598                 prev_md = md;
 599         }
 600 }
 601
 602 static void __init get_systab_virt_addr(efi_memory_desc_t *md)
 603 {
 604         unsigned long size;
 605         u64 end, systab;
 606
 607         size = md->num_pages << EFI_PAGE_SHIFT;
 608         end = md->phys_addr + size;
 609         systab = (u64)(unsigned long)efi_phys.systab;
 610         if (md->phys_addr <= systab && systab < end) {
 611                 systab += md->virt_addr - md->phys_addr;
 612                 efi.systab = (efi_system_table_t *)(unsigned long)systab;
 613         }
 614 }
 615
 616 static void __init save_runtime_map(void)
 617 {
 618 #ifdef CONFIG_KEXEC
 619         efi_memory_desc_t *md;
 620         void *tmp, *p, *q = NULL;
 621         int count = 0;
 622
 623         if (efi_enabled(EFI_OLD_MEMMAP))
 624                 return;
 625
 626         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 627                 md = p;
 628
 629                 if (!(md->attribute & EFI_MEMORY_RUNTIME) ||
 630                     (md->type == EFI_BOOT_SERVICES_CODE) ||
 631                     (md->type == EFI_BOOT_SERVICES_DATA))
 632                         continue;
 633                 tmp = krealloc(q, (count + 1) * memmap.desc_size, GFP_KERNEL);
 634                 if (!tmp)
 635                         goto out;
 636                 q = tmp;
 637
 638                 memcpy(q + count * memmap.desc_size, md, memmap.desc_size);
 639                 count++;
 640         }
 641
 642         efi_runtime_map_setup(q, count, memmap.desc_size);
 643         return;
 644
 645 out:
 646         kfree(q);
 647         pr_err("Error saving runtime map, efi runtime on kexec non-functional!!\n");
 648 #endif
 649 }
 650
 651 static void *realloc_pages(void *old_memmap, int old_shift)
 652 {
 653         void *ret;
 654
 655         ret = (void *)__get_free_pages(GFP_KERNEL, old_shift + 1);
 656         if (!ret)
 657                 goto out;
 658
 659         /*
 660          * A first-time allocation doesn't have anything to copy.
 661          */
 662         if (!old_memmap)
 663                 return ret;
 664
 665         memcpy(ret, old_memmap, PAGE_SIZE << old_shift);
 666
 667 out:
 668         free_pages((unsigned long)old_memmap, old_shift);
 669         return ret;
 670 }
 671
 672 /*
 673  * Map the efi memory ranges of the runtime services and update new_mmap with
 674  * virtual addresses.
 675  */
 676 static void * __init efi_map_regions(int *count, int *pg_shift)
 677 {
 678         void *p, *new_memmap = NULL;
 679         unsigned long left = 0;
 680         efi_memory_desc_t *md;
 681
 682         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 683                 md = p;
 684                 if (!(md->attribute & EFI_MEMORY_RUNTIME)) {
 685 #ifdef CONFIG_X86_64
 686                         if (md->type != EFI_BOOT_SERVICES_CODE &&
 687                             md->type != EFI_BOOT_SERVICES_DATA)
 688 #endif
 689                                 continue;
 690                 }
 691
 692                 efi_map_region(md);
 693                 get_systab_virt_addr(md);
 694
 695                 if (left < memmap.desc_size) {
 696                         new_memmap = realloc_pages(new_memmap, *pg_shift);
 697                         if (!new_memmap)
 698                                 return NULL;
 699
 700                         left += PAGE_SIZE << *pg_shift;
 701                         (*pg_shift)++;
 702                 }
 703
 704                 memcpy(new_memmap + (*count * memmap.desc_size), md,
 705                        memmap.desc_size);
 706
 707                 left -= memmap.desc_size;
 708                 (*count)++;
 709         }
 710
 711         return new_memmap;
 712 }
 713
 714 static void __init kexec_enter_virtual_mode(void)
 715 {
 716 #ifdef CONFIG_KEXEC
 717         efi_memory_desc_t *md;
 718         void *p;
 719
 720         efi.systab = NULL;
 721
 722         /*
 723          * We don't do virtual mode, since we don't do runtime services, on
 724          * non-native EFI
 725          */
 726         if (!efi_is_native()) {
 727                 efi_unmap_memmap();
 728                 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 729                 return;
 730         }
 731
 732         /*
 733         * Map efi regions which were passed via setup_data. The virt_addr is a
 734         * fixed addr which was used in first kernel of a kexec boot.
 735         */
 736         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 737                 md = p;
 738                 efi_map_region_fixed(md); /* FIXME: add error handling */
 739                 get_systab_virt_addr(md);
 740         }
 741
 742         save_runtime_map();
 743
 744         BUG_ON(!efi.systab);
 745
 746         efi_sync_low_kernel_mappings();
 747
 748         /*
 749          * Now that EFI is in virtual mode, update the function
 750          * pointers in the runtime service table to the new virtual addresses.
 751          *
 752          * Call EFI services through wrapper functions.
 753          */
 754         efi.runtime_version = efi_systab.hdr.revision;
 755
 756         efi_native_runtime_setup();
 757
 758         efi.set_virtual_address_map = NULL;
 759
 760         if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX))
 761                 runtime_code_page_mkexec();
 762
 763         /* clean DUMMY object */
 764         efi_delete_dummy_variable();
 765 #endif
 766 }
 767
 768 /*
 769  * This function will switch the EFI runtime services to virtual mode.
 770  * Essentially, we look through the EFI memmap and map every region that
 771  * has the runtime attribute bit set in its memory descriptor into the
 772  * ->trampoline_pgd page table using a top-down VA allocation scheme.
 773  *
 774  * The old method which used to update that memory descriptor with the
 775  * virtual address obtained from ioremap() is still supported when the
 776  * kernel is booted with efi=old_map on its command line. Same old
 777  * method enabled the runtime services to be called without having to
 778  * thunk back into physical mode for every invocation.
 779  *
 780  * The new method does a pagetable switch in a preemption-safe manner
 781  * so that we're in a different address space when calling a runtime
 782  * function. For function arguments passing we do copy the PGDs of the
 783  * kernel page table into ->trampoline_pgd prior to each call.
 784  *
 785  * Specially for kexec boot, efi runtime maps in previous kernel should
 786  * be passed in via setup_data. In that case runtime ranges will be mapped
 787  * to the same virtual addresses as the first kernel, see
 788  * kexec_enter_virtual_mode().
 789  */
 790 static void __init __efi_enter_virtual_mode(void)
 791 {
 792         int count = 0, pg_shift = 0;
 793         void *new_memmap = NULL;
 794         efi_status_t status;
 795
 796         efi.systab = NULL;
 797
 798         efi_merge_regions();
 799         new_memmap = efi_map_regions(&count, &pg_shift);
 800         if (!new_memmap) {
 801                 pr_err("Error reallocating memory, EFI runtime non-functional!\n");
 802                 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 803                 return;
 804         }
 805
 806         save_runtime_map();
 807
 808         BUG_ON(!efi.systab);
 809
 810         if (efi_setup_page_tables(__pa(new_memmap), 1 << pg_shift)) {
 811                 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 812                 return;
 813         }
 814
 815         efi_sync_low_kernel_mappings();
 816         efi_dump_pagetable();
 817
 818         if (efi_is_native()) {
 819                 status = phys_efi_set_virtual_address_map(
 820                                 memmap.desc_size * count,
 821                                 memmap.desc_size,
 822                                 memmap.desc_version,
 823                                 (efi_memory_desc_t *)__pa(new_memmap));
 824         } else {
 825                 status = efi_thunk_set_virtual_address_map(
 826                                 efi_phys.set_virtual_address_map,
 827                                 memmap.desc_size * count,
 828                                 memmap.desc_size,
 829                                 memmap.desc_version,
 830                                 (efi_memory_desc_t *)__pa(new_memmap));
 831         }
 832
 833         if (status != EFI_SUCCESS) {
 834                 pr_alert("Unable to switch EFI into virtual mode (status=%lx)!\n",
 835                          status);
 836                 panic("EFI call to SetVirtualAddressMap() failed!");
 837         }
 838
 839         /*
 840          * Now that EFI is in virtual mode, update the function
 841          * pointers in the runtime service table to the new virtual addresses.
 842          *
 843          * Call EFI services through wrapper functions.
 844          */
 845         efi.runtime_version = efi_systab.hdr.revision;
 846
 847         if (efi_is_native())
 848                 efi_native_runtime_setup();
 849         else
 850                 efi_thunk_runtime_setup();
 851
 852         efi.set_virtual_address_map = NULL;
 853
 854         efi_runtime_mkexec();
 855
 856         /*
 857          * We mapped the descriptor array into the EFI pagetable above but we're
 858          * not unmapping it here. Here's why:
 859          *
 860          * We're copying select PGDs from the kernel page table to the EFI page
 861          * table and when we do so and make changes to those PGDs like unmapping
 862          * stuff from them, those changes appear in the kernel page table and we
 863          * go boom.
 864          *
 865          * From setup_real_mode():
 866          *
 867          * ...
 868          * trampoline_pgd[0] = init_level4_pgt[pgd_index(__PAGE_OFFSET)].pgd;
 869          *
 870          * In this particular case, our allocation is in PGD 0 of the EFI page
 871          * table but we've copied that PGD from PGD[272] of the EFI page table:
 872          *
 873          *      pgd_index(__PAGE_OFFSET = 0xffff880000000000) = 272
 874          *
 875          * where the direct memory mapping in kernel space is.
 876          *
 877          * new_memmap's VA comes from that direct mapping and thus clearing it,
 878          * it would get cleared in the kernel page table too.
 879          *
 880          * efi_cleanup_page_tables(__pa(new_memmap), 1 << pg_shift);
 881          */
 882         free_pages((unsigned long)new_memmap, pg_shift);
 883
 884         /* clean DUMMY object */
 885         efi_delete_dummy_variable();
 886 }
 887
 888 void __init efi_enter_virtual_mode(void)
 889 {
 890         if (efi_enabled(EFI_PARAVIRT))
 891                 return;
 892
 893         if (efi_setup)
 894                 kexec_enter_virtual_mode();
 895         else
 896                 __efi_enter_virtual_mode();
 897 }
 898
 899 /*
 900  * Convenience functions to obtain memory types and attributes
 901  */
 902 u32 efi_mem_type(unsigned long phys_addr)
 903 {
 904         efi_memory_desc_t *md;
 905         void *p;
 906
 907         if (!efi_enabled(EFI_MEMMAP))
 908                 return 0;
 909
 910         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 911                 md = p;
 912                 if ((md->phys_addr <= phys_addr) &&
 913                     (phys_addr < (md->phys_addr +
 914                                   (md->num_pages << EFI_PAGE_SHIFT))))
 915                         return md->type;
 916         }
 917         return 0;
 918 }
 919
 920 u64 efi_mem_attributes(unsigned long phys_addr)
 921 {
 922         efi_memory_desc_t *md;
 923         void *p;
 924
 925         if (!efi_enabled(EFI_MEMMAP))
 926                 return 0;
 927
 928         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 929                 md = p;
 930                 if ((md->phys_addr <= phys_addr) &&
 931                     (phys_addr < (md->phys_addr +
 932                                   (md->num_pages << EFI_PAGE_SHIFT))))
 933                         return md->attribute;
 934         }
 935         return 0;
 936 }
 937
 938 static int __init arch_parse_efi_cmdline(char *str)
 939 {
 940         if (parse_option_str(str, "old_map"))
 941                 set_bit(EFI_OLD_MEMMAP, &efi.flags);
 942
 943         return 0;
 944 }
 945 early_param("efi", arch_parse_efi_cmdline);