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                 retval = -EINVAL;
  93                 goto out;
  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                 early_memunmap(c16, sizeof(vendor));
 108         }
 109
 110         pr_info("EFI v%u.%.02u by %s\n",
 111                 efi.systab->hdr.revision >> 16,
 112                 efi.systab->hdr.revision & 0xffff, vendor);
 113
 114         retval = efi_config_init(NULL);
 115         if (retval == 0)
 116                 set_bit(EFI_CONFIG_TABLES, &efi.flags);
 117
 118 out:
 119         early_memunmap(efi.systab,  sizeof(efi_system_table_t));
 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
 194
 195 static u64 __init free_one_region(u64 start, u64 end)
 196 {
 197         u64 size = end - start;
 198
 199         if (uefi_debug)
 200                 pr_info("  EFI freeing: 0x%012llx-0x%012llx\n", start, end - 1);
 201
 202         free_bootmem_late(start, size);
 203         return size;
 204 }
 205
 206 static u64 __init free_region(u64 start, u64 end)
 207 {
 208         u64 map_start, map_end, total = 0;
 209
 210         if (end <= start)
 211                 return total;
 212
 213         map_start = (u64)memmap.phys_map;
 214         map_end = PAGE_ALIGN(map_start + (memmap.map_end - memmap.map));
 215         map_start &= PAGE_MASK;
 216
 217         if (start < map_end && end > map_start) {
 218                 /* region overlaps UEFI memmap */
 219                 if (start < map_start)
 220                         total += free_one_region(start, map_start);
 221
 222                 if (map_end < end)
 223                         total += free_one_region(map_end, end);
 224         } else
 225                 total += free_one_region(start, end);
 226
 227         return total;
 228 }
 229
 230 static void __init free_boot_services(void)
 231 {
 232         u64 total_freed = 0;
 233         u64 keep_end, free_start, free_end;
 234         efi_memory_desc_t *md;
 235
 236         /*
 237          * If kernel uses larger pages than UEFI, we have to be careful
 238          * not to inadvertantly free memory we want to keep if there is
 239          * overlap at the kernel page size alignment. We do not want to
 240          * free is_reserve_region() memory nor the UEFI memmap itself.
 241          *
 242          * The memory map is sorted, so we keep track of the end of
 243          * any previous region we want to keep, remember any region
 244          * we want to free and defer freeing it until we encounter
 245          * the next region we want to keep. This way, before freeing
 246          * it, we can clip it as needed to avoid freeing memory we
 247          * want to keep for UEFI.
 248          */
 249
 250         keep_end = 0;
 251         free_start = 0;
 252
 253         for_each_efi_memory_desc(&memmap, md) {
 254                 u64 paddr, npages, size;
 255
 256                 if (is_reserve_region(md)) {
 257                         /*
 258                          * We don't want to free any memory from this region.
 259                          */
 260                         if (free_start) {
 261                                 /* adjust free_end then free region */
 262                                 if (free_end > md->phys_addr)
 263                                         free_end -= PAGE_SIZE;
 264                                 total_freed += free_region(free_start, free_end);
 265                                 free_start = 0;
 266                         }
 267                         keep_end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);
 268                         continue;
 269                 }
 270
 271                 if (md->type != EFI_BOOT_SERVICES_CODE &&
 272                     md->type != EFI_BOOT_SERVICES_DATA) {
 273                         /* no need to free this region */
 274                         continue;
 275                 }
 276
 277                 /*
 278                  * We want to free memory from this region.
 279                  */
 280                 paddr = md->phys_addr;
 281                 npages = md->num_pages;
 282                 memrange_efi_to_native(&paddr, &npages);
 283                 size = npages << PAGE_SHIFT;
 284
 285                 if (free_start) {
 286                         if (paddr <= free_end)
 287                                 free_end = paddr + size;
 288                         else {
 289                                 total_freed += free_region(free_start, free_end);
 290                                 free_start = paddr;
 291                                 free_end = paddr + size;
 292                         }
 293                 } else {
 294                         free_start = paddr;
 295                         free_end = paddr + size;
 296                 }
 297                 if (free_start < keep_end) {
 298                         free_start += PAGE_SIZE;
 299                         if (free_start >= free_end)
 300                                 free_start = 0;
 301                 }
 302         }
 303         if (free_start)
 304                 total_freed += free_region(free_start, free_end);
 305
 306         if (total_freed)
 307                 pr_info("Freed 0x%llx bytes of EFI boot services memory",
 308                         total_freed);
 309 }
 310
 311 void __init efi_init(void)
 312 {
 313         struct efi_fdt_params params;
 314
 315         /* Grab UEFI information placed in FDT by stub */
 316         if (!efi_get_fdt_params(&params, uefi_debug))
 317                 return;
 318
 319         efi_system_table = params.system_table;
 320
 321         memblock_reserve(params.mmap & PAGE_MASK,
 322                          PAGE_ALIGN(params.mmap_size + (params.mmap & ~PAGE_MASK)));
 323         memmap.phys_map = (void *)params.mmap;
 324         memmap.map = early_memremap(params.mmap, params.mmap_size);
 325         memmap.map_end = memmap.map + params.mmap_size;
 326         memmap.desc_size = params.desc_size;
 327         memmap.desc_version = params.desc_ver;
 328
 329         if (uefi_init() < 0)
 330                 return;
 331
 332         reserve_regions();
 333 }
 334
 335 void __init efi_idmap_init(void)
 336 {
 337         if (!efi_enabled(EFI_BOOT))
 338                 return;
 339
 340         /* boot time idmap_pg_dir is incomplete, so fill in missing parts */
 341         efi_setup_idmap();
 342 }
 343
 344 static int __init remap_region(efi_memory_desc_t *md, void **new)
 345 {
 346         u64 paddr, vaddr, npages, size;
 347
 348         paddr = md->phys_addr;
 349         npages = md->num_pages;
 350         memrange_efi_to_native(&paddr, &npages);
 351         size = npages << PAGE_SHIFT;
 352
 353         if (is_normal_ram(md))
 354                 vaddr = (__force u64)ioremap_cache(paddr, size);
 355         else
 356                 vaddr = (__force u64)ioremap(paddr, size);
 357
 358         if (!vaddr) {
 359                 pr_err("Unable to remap 0x%llx pages @ %p\n",
 360                        npages, (void *)paddr);
 361                 return 0;
 362         }
 363
 364         /* adjust for any rounding when EFI and system pagesize differs */
 365         md->virt_addr = vaddr + (md->phys_addr - paddr);
 366
 367         if (uefi_debug)
 368                 pr_info("  EFI remap 0x%012llx => %p\n",
 369                         md->phys_addr, (void *)md->virt_addr);
 370
 371         memcpy(*new, md, memmap.desc_size);
 372         *new += memmap.desc_size;
 373
 374         return 1;
 375 }
 376
 377 /*
 378  * Switch UEFI from an identity map to a kernel virtual map
 379  */
 380 static int __init arm64_enter_virtual_mode(void)
 381 {
 382         efi_memory_desc_t *md;
 383         phys_addr_t virtmap_phys;
 384         void *virtmap, *virt_md;
 385         efi_status_t status;
 386         u64 mapsize;
 387         int count = 0;
 388         unsigned long flags;
 389
 390         if (!efi_enabled(EFI_BOOT)) {
 391                 pr_info("EFI services will not be available.\n");
 392                 return -1;
 393         }
 394
 395         mapsize = memmap.map_end - memmap.map;
 396         early_memunmap(memmap.map, mapsize);
 397
 398         if (efi_runtime_disabled()) {
 399                 pr_info("EFI runtime services will be disabled.\n");
 400                 return -1;
 401         }
 402
 403         pr_info("Remapping and enabling EFI services.\n");
 404         /* replace early memmap mapping with permanent mapping */
 405         memmap.map = (__force void *)ioremap_cache((phys_addr_t)memmap.phys_map,
 406                                                    mapsize);
 407         memmap.map_end = memmap.map + mapsize;
 408
 409         efi.memmap = &memmap;
 410
 411         /* Map the runtime regions */
 412         virtmap = kmalloc(mapsize, GFP_KERNEL);
 413         if (!virtmap) {
 414                 pr_err("Failed to allocate EFI virtual memmap\n");
 415                 return -1;
 416         }
 417         virtmap_phys = virt_to_phys(virtmap);
 418         virt_md = virtmap;
 419
 420         for_each_efi_memory_desc(&memmap, md) {
 421                 if (!(md->attribute & EFI_MEMORY_RUNTIME))
 422                         continue;
 423                 if (!remap_region(md, &virt_md))
 424                         goto err_unmap;
 425                 ++count;
 426         }
 427
 428         efi.systab = (__force void *)efi_lookup_mapped_addr(efi_system_table);
 429         if (!efi.systab) {
 430                 /*
 431                  * If we have no virtual mapping for the System Table at this
 432                  * point, the memory map doesn't cover the physical offset where
 433                  * it resides. This means the System Table will be inaccessible
 434                  * to Runtime Services themselves once the virtual mapping is
 435                  * installed.
 436                  */
 437                 pr_err("Failed to remap EFI System Table -- buggy firmware?\n");
 438                 goto err_unmap;
 439         }
 440         set_bit(EFI_SYSTEM_TABLES, &efi.flags);
 441
 442         local_irq_save(flags);
 443         cpu_switch_mm(idmap_pg_dir, &init_mm);
 444
 445         /* Call SetVirtualAddressMap with the physical address of the map */
 446         runtime = efi.systab->runtime;
 447         efi.set_virtual_address_map = runtime->set_virtual_address_map;
 448
 449         status = efi.set_virtual_address_map(count * memmap.desc_size,
 450                                              memmap.desc_size,
 451                                              memmap.desc_version,
 452                                              (efi_memory_desc_t *)virtmap_phys);
 453         cpu_set_reserved_ttbr0();
 454         flush_tlb_all();
 455         local_irq_restore(flags);
 456
 457         kfree(virtmap);
 458
 459         free_boot_services();
 460
 461         if (status != EFI_SUCCESS) {
 462                 pr_err("Failed to set EFI virtual address map! [%lx]\n",
 463                         status);
 464                 return -1;
 465         }
 466
 467         /* Set up runtime services function pointers */
 468         runtime = efi.systab->runtime;
 469         efi_native_runtime_setup();
 470         set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 471
 472         return 0;
 473
 474 err_unmap:
 475         /* unmap all mappings that succeeded: there are 'count' of those */
 476         for (virt_md = virtmap; count--; virt_md += memmap.desc_size) {
 477                 md = virt_md;
 478                 iounmap((__force void __iomem *)md->virt_addr);
 479         }
 480         kfree(virtmap);
 481         return -1;
 482 }
 483 early_initcall(arm64_enter_virtual_mode);