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