arch/arm64/kernel/efi.c

   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/dmi.h>
  15 #include <linux/efi.h>
  16 #include <linux/export.h>
  17 #include <linux/memblock.h>
  18 #include <linux/bootmem.h>
  19 #include <linux/of.h>
  20 #include <linux/of_fdt.h>
  21 #include <linux/sched.h>
  22 #include <linux/slab.h>
  23
  24 #include <asm/cacheflush.h>
  25 #include <asm/efi.h>
  26 #include <asm/tlbflush.h>
  27 #include <asm/mmu_context.h>
  28
  29 struct efi_memory_map memmap;
  30
  31 static efi_runtime_services_t *runtime;
  32
  33 static u64 efi_system_table;
  34
  35 static int uefi_debug __initdata;
  36 static int __init uefi_debug_setup(char *str)
  37 {
  38         uefi_debug = 1;
  39
  40         return 0;
  41 }
  42 early_param("uefi_debug", uefi_debug_setup);
  43
  44 static int __init is_normal_ram(efi_memory_desc_t *md)
  45 {
  46         if (md->attribute & EFI_MEMORY_WB)
  47                 return 1;
  48         return 0;
  49 }
  50
  51 static void __init efi_setup_idmap(void)
  52 {
  53         struct memblock_region *r;
  54         efi_memory_desc_t *md;
  55         u64 paddr, npages, size;
  56
  57         for_each_memblock(memory, r)
  58                 create_id_mapping(r->base, r->size, 0);
  59
  60         /* map runtime io spaces */
  61         for_each_efi_memory_desc(&memmap, md) {
  62                 if (!(md->attribute & EFI_MEMORY_RUNTIME) || is_normal_ram(md))
  63                         continue;
  64                 paddr = md->phys_addr;
  65                 npages = md->num_pages;
  66                 memrange_efi_to_native(&paddr, &npages);
  67                 size = npages << PAGE_SHIFT;
  68                 create_id_mapping(paddr, size, 1);
  69         }
  70 }
  71
  72 static int __init uefi_init(void)
  73 {
  74         efi_char16_t *c16;
  75         char vendor[100] = "unknown";
  76         int i, retval;
  77
  78         efi.systab = early_memremap(efi_system_table,
  79                                     sizeof(efi_system_table_t));
  80         if (efi.systab == NULL) {
  81                 pr_warn("Unable to map EFI system table.\n");
  82                 return -ENOMEM;
  83         }
  84
  85         set_bit(EFI_BOOT, &efi.flags);
  86         set_bit(EFI_64BIT, &efi.flags);
  87
  88         /*
  89          * Verify the EFI Table
  90          */
  91         if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
  92                 pr_err("System table signature incorrect\n");
  93                 return -EINVAL;
  94         }
  95         if ((efi.systab->hdr.revision >> 16) < 2)
  96                 pr_warn("Warning: EFI system table version %d.%02d, expected 2.00 or greater\n",
  97                         efi.systab->hdr.revision >> 16,
  98                         efi.systab->hdr.revision & 0xffff);
  99
 100         /* Show what we know for posterity */
 101         c16 = early_memremap(efi.systab->fw_vendor,
 102                              sizeof(vendor));
 103         if (c16) {
 104                 for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
 105                         vendor[i] = c16[i];
 106                 vendor[i] = '\0';
 107         }
 108
 109         pr_info("EFI v%u.%.02u by %s\n",
 110                 efi.systab->hdr.revision >> 16,
 111                 efi.systab->hdr.revision & 0xffff, vendor);
 112
 113         retval = efi_config_init(NULL);
 114         if (retval == 0)
 115                 set_bit(EFI_CONFIG_TABLES, &efi.flags);
 116
 117         early_memunmap(c16, sizeof(vendor));
 118         early_memunmap(efi.systab,  sizeof(efi_system_table_t));
 119
 120         return retval;
 121 }
 122
 123 static __initdata char memory_type_name[][32] = {
 124         {"Reserved"},
 125         {"Loader Code"},
 126         {"Loader Data"},
 127         {"Boot Code"},
 128         {"Boot Data"},
 129         {"Runtime Code"},
 130         {"Runtime Data"},
 131         {"Conventional Memory"},
 132         {"Unusable Memory"},
 133         {"ACPI Reclaim Memory"},
 134         {"ACPI Memory NVS"},
 135         {"Memory Mapped I/O"},
 136         {"MMIO Port Space"},
 137         {"PAL Code"},
 138 };
 139
 140 /*
 141  * Return true for RAM regions we want to permanently reserve.
 142  */
 143 static __init int is_reserve_region(efi_memory_desc_t *md)
 144 {
 145         if (!is_normal_ram(md))
 146                 return 0;
 147
 148         if (md->attribute & EFI_MEMORY_RUNTIME)
 149                 return 1;
 150
 151         if (md->type == EFI_ACPI_RECLAIM_MEMORY ||
 152             md->type == EFI_RESERVED_TYPE)
 153                 return 1;
 154
 155         return 0;
 156 }
 157
 158 static __init void reserve_regions(void)
 159 {
 160         efi_memory_desc_t *md;
 161         u64 paddr, npages, size;
 162
 163         if (uefi_debug)
 164                 pr_info("Processing EFI memory map:\n");
 165
 166         for_each_efi_memory_desc(&memmap, md) {
 167                 paddr = md->phys_addr;
 168                 npages = md->num_pages;
 169
 170                 if (uefi_debug)
 171                         pr_info("  0x%012llx-0x%012llx [%s]",
 172                                 paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
 173                                 memory_type_name[md->type]);
 174
 175                 memrange_efi_to_native(&paddr, &npages);
 176                 size = npages << PAGE_SHIFT;
 177
 178                 if (is_normal_ram(md))
 179                         early_init_dt_add_memory_arch(paddr, size);
 180
 181                 if (is_reserve_region(md) ||
 182                     md->type == EFI_BOOT_SERVICES_CODE ||
 183                     md->type == EFI_BOOT_SERVICES_DATA) {
 184                         memblock_reserve(paddr, size);
 185                         if (uefi_debug)
 186                                 pr_cont("*");
 187                 }
 188
 189                 if (uefi_debug)
 190                         pr_cont("\n");
 191         }
 192
 193         set_bit(EFI_MEMMAP, &efi.flags);
 194 }
 195
 196
 197 static u64 __init free_one_region(u64 start, u64 end)
 198 {
 199         u64 size = end - start;
 200
 201         if (uefi_debug)
 202                 pr_info("  EFI freeing: 0x%012llx-0x%012llx\n", start, end - 1);
 203
 204         free_bootmem_late(start, size);
 205         return size;
 206 }
 207
 208 static u64 __init free_region(u64 start, u64 end)
 209 {
 210         u64 map_start, map_end, total = 0;
 211
 212         if (end <= start)
 213                 return total;
 214
 215         map_start = (u64)memmap.phys_map;
 216         map_end = PAGE_ALIGN(map_start + (memmap.map_end - memmap.map));
 217         map_start &= PAGE_MASK;
 218
 219         if (start < map_end && end > map_start) {
 220                 /* region overlaps UEFI memmap */
 221                 if (start < map_start)
 222                         total += free_one_region(start, map_start);
 223
 224                 if (map_end < end)
 225                         total += free_one_region(map_end, end);
 226         } else
 227                 total += free_one_region(start, end);
 228
 229         return total;
 230 }
 231
 232 static void __init free_boot_services(void)
 233 {
 234         u64 total_freed = 0;
 235         u64 keep_end, free_start, free_end;
 236         efi_memory_desc_t *md;
 237
 238         /*
 239          * If kernel uses larger pages than UEFI, we have to be careful
 240          * not to inadvertantly free memory we want to keep if there is
 241          * overlap at the kernel page size alignment. We do not want to
 242          * free is_reserve_region() memory nor the UEFI memmap itself.
 243          *
 244          * The memory map is sorted, so we keep track of the end of
 245          * any previous region we want to keep, remember any region
 246          * we want to free and defer freeing it until we encounter
 247          * the next region we want to keep. This way, before freeing
 248          * it, we can clip it as needed to avoid freeing memory we
 249          * want to keep for UEFI.
 250          */
 251
 252         keep_end = 0;
 253         free_start = 0;
 254
 255         for_each_efi_memory_desc(&memmap, md) {
 256                 u64 paddr, npages, size;
 257
 258                 if (is_reserve_region(md)) {
 259                         /*
 260                          * We don't want to free any memory from this region.
 261                          */
 262                         if (free_start) {
 263                                 /* adjust free_end then free region */
 264                                 if (free_end > md->phys_addr)
 265                                         free_end -= PAGE_SIZE;
 266                                 total_freed += free_region(free_start, free_end);
 267                                 free_start = 0;
 268                         }
 269                         keep_end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);
 270                         continue;
 271                 }
 272
 273                 if (md->type != EFI_BOOT_SERVICES_CODE &&
 274                     md->type != EFI_BOOT_SERVICES_DATA) {
 275                         /* no need to free this region */
 276                         continue;
 277                 }
 278
 279                 /*
 280                  * We want to free memory from this region.
 281                  */
 282                 paddr = md->phys_addr;
 283                 npages = md->num_pages;
 284                 memrange_efi_to_native(&paddr, &npages);
 285                 size = npages << PAGE_SHIFT;
 286
 287                 if (free_start) {
 288                         if (paddr <= free_end)
 289                                 free_end = paddr + size;
 290                         else {
 291                                 total_freed += free_region(free_start, free_end);
 292                                 free_start = paddr;
 293                                 free_end = paddr + size;
 294                         }
 295                 } else {
 296                         free_start = paddr;
 297                         free_end = paddr + size;
 298                 }
 299                 if (free_start < keep_end) {
 300                         free_start += PAGE_SIZE;
 301                         if (free_start >= free_end)
 302                                 free_start = 0;
 303                 }
 304         }
 305         if (free_start)
 306                 total_freed += free_region(free_start, free_end);
 307
 308         if (total_freed)
 309                 pr_info("Freed 0x%llx bytes of EFI boot services memory",
 310                         total_freed);
 311 }
 312
 313 void __init efi_init(void)
 314 {
 315         struct efi_fdt_params params;
 316
 317         /* Grab UEFI information placed in FDT by stub */
 318         if (!efi_get_fdt_params(&params, uefi_debug))
 319                 return;
 320
 321         efi_system_table = params.system_table;
 322
 323         memblock_reserve(params.mmap & PAGE_MASK,
 324                          PAGE_ALIGN(params.mmap_size + (params.mmap & ~PAGE_MASK)));
 325         memmap.phys_map = (void *)params.mmap;
 326         memmap.map = early_memremap(params.mmap, params.mmap_size);
 327         memmap.map_end = memmap.map + params.mmap_size;
 328         memmap.desc_size = params.desc_size;
 329         memmap.desc_version = params.desc_ver;
 330
 331         if (uefi_init() < 0)
 332                 return;
 333
 334         reserve_regions();
 335 }
 336
 337 void __init efi_idmap_init(void)
 338 {
 339         if (!efi_enabled(EFI_BOOT))
 340                 return;
 341
 342         /* boot time idmap_pg_dir is incomplete, so fill in missing parts */
 343         efi_setup_idmap();
 344 }
 345
 346 static int __init remap_region(efi_memory_desc_t *md, void **new)
 347 {
 348         u64 paddr, vaddr, npages, size;
 349
 350         paddr = md->phys_addr;
 351         npages = md->num_pages;
 352         memrange_efi_to_native(&paddr, &npages);
 353         size = npages << PAGE_SHIFT;
 354
 355         if (is_normal_ram(md))
 356                 vaddr = (__force u64)ioremap_cache(paddr, size);
 357         else
 358                 vaddr = (__force u64)ioremap(paddr, size);
 359
 360         if (!vaddr) {
 361                 pr_err("Unable to remap 0x%llx pages @ %p\n",
 362                        npages, (void *)paddr);
 363                 return 0;
 364         }
 365
 366         /* adjust for any rounding when EFI and system pagesize differs */
 367         md->virt_addr = vaddr + (md->phys_addr - paddr);
 368
 369         if (uefi_debug)
 370                 pr_info("  EFI remap 0x%012llx => %p\n",
 371                         md->phys_addr, (void *)md->virt_addr);
 372
 373         memcpy(*new, md, memmap.desc_size);
 374         *new += memmap.desc_size;
 375
 376         return 1;
 377 }
 378
 379 /*
 380  * Switch UEFI from an identity map to a kernel virtual map
 381  */
 382 static int __init arm64_enter_virtual_mode(void)
 383 {
 384         efi_memory_desc_t *md;
 385         phys_addr_t virtmap_phys;
 386         void *virtmap, *virt_md;
 387         efi_status_t status;
 388         u64 mapsize;
 389         int count = 0;
 390         unsigned long flags;
 391
 392         if (!efi_enabled(EFI_BOOT)) {
 393                 pr_info("EFI services will not be available.\n");
 394                 return -1;
 395         }
 396
 397         pr_info("Remapping and enabling EFI services.\n");
 398
 399         /* replace early memmap mapping with permanent mapping */
 400         mapsize = memmap.map_end - memmap.map;
 401         early_memunmap(memmap.map, mapsize);
 402         memmap.map = (__force void *)ioremap_cache((phys_addr_t)memmap.phys_map,
 403                                                    mapsize);
 404         memmap.map_end = memmap.map + mapsize;
 405
 406         efi.memmap = &memmap;
 407
 408         /* Map the runtime regions */
 409         virtmap = kmalloc(mapsize, GFP_KERNEL);
 410         if (!virtmap) {
 411                 pr_err("Failed to allocate EFI virtual memmap\n");
 412                 return -1;
 413         }
 414         virtmap_phys = virt_to_phys(virtmap);
 415         virt_md = virtmap;
 416
 417         for_each_efi_memory_desc(&memmap, md) {
 418                 if (!(md->attribute & EFI_MEMORY_RUNTIME))
 419                         continue;
 420                 if (!remap_region(md, &virt_md))
 421                         goto err_unmap;
 422                 ++count;
 423         }
 424
 425         efi.systab = (__force void *)efi_lookup_mapped_addr(efi_system_table);
 426         if (!efi.systab) {
 427                 /*
 428                  * If we have no virtual mapping for the System Table at this
 429                  * point, the memory map doesn't cover the physical offset where
 430                  * it resides. This means the System Table will be inaccessible
 431                  * to Runtime Services themselves once the virtual mapping is
 432                  * installed.
 433                  */
 434                 pr_err("Failed to remap EFI System Table -- buggy firmware?\n");
 435                 goto err_unmap;
 436         }
 437         set_bit(EFI_SYSTEM_TABLES, &efi.flags);
 438
 439         /*
 440          * DMI depends on EFI on arm64, and dmi_scan_machine() needs to be
 441          * called early because dmi_id_init(), which is an arch_initcall itself,
 442          * depends on dmi_scan_machine() having been called already.
 443          */
 444         dmi_scan_machine();
 445
 446         local_irq_save(flags);
 447         cpu_switch_mm(idmap_pg_dir, &init_mm);
 448
 449         /* Call SetVirtualAddressMap with the physical address of the map */
 450         runtime = efi.systab->runtime;
 451         efi.set_virtual_address_map = runtime->set_virtual_address_map;
 452
 453         status = efi.set_virtual_address_map(count * memmap.desc_size,
 454                                              memmap.desc_size,
 455                                              memmap.desc_version,
 456                                              (efi_memory_desc_t *)virtmap_phys);
 457         cpu_set_reserved_ttbr0();
 458         flush_tlb_all();
 459         local_irq_restore(flags);
 460
 461         kfree(virtmap);
 462
 463         free_boot_services();
 464
 465         if (status != EFI_SUCCESS) {
 466                 pr_err("Failed to set EFI virtual address map! [%lx]\n",
 467                         status);
 468                 return -1;
 469         }
 470
 471         /* Set up runtime services function pointers */
 472         runtime = efi.systab->runtime;
 473         efi_native_runtime_setup();
 474         set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 475
 476         efi.runtime_version = efi.systab->hdr.revision;
 477
 478         return 0;
 479
 480 err_unmap:
 481         /* unmap all mappings that succeeded: there are 'count' of those */
 482         for (virt_md = virtmap; count--; virt_md += memmap.desc_size) {
 483                 md = virt_md;
 484                 iounmap((__force void __iomem *)md->virt_addr);
 485         }
 486         kfree(virtmap);
 487         return -1;
 488 }
 489 early_initcall(arm64_enter_virtual_mode);