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         set_bit(EFI_MEMMAP, &efi.flags);
 193 }
 194
 195
 196 static u64 __init free_one_region(u64 start, u64 end)
 197 {
 198         u64 size = end - start;
 199
 200         if (uefi_debug)
 201                 pr_info("  EFI freeing: 0x%012llx-0x%012llx\n", start, end - 1);
 202
 203         free_bootmem_late(start, size);
 204         return size;
 205 }
 206
 207 static u64 __init free_region(u64 start, u64 end)
 208 {
 209         u64 map_start, map_end, total = 0;
 210
 211         if (end <= start)
 212                 return total;
 213
 214         map_start = (u64)memmap.phys_map;
 215         map_end = PAGE_ALIGN(map_start + (memmap.map_end - memmap.map));
 216         map_start &= PAGE_MASK;
 217
 218         if (start < map_end && end > map_start) {
 219                 /* region overlaps UEFI memmap */
 220                 if (start < map_start)
 221                         total += free_one_region(start, map_start);
 222
 223                 if (map_end < end)
 224                         total += free_one_region(map_end, end);
 225         } else
 226                 total += free_one_region(start, end);
 227
 228         return total;
 229 }
 230
 231 static void __init free_boot_services(void)
 232 {
 233         u64 total_freed = 0;
 234         u64 keep_end, free_start, free_end;
 235         efi_memory_desc_t *md;
 236
 237         /*
 238          * If kernel uses larger pages than UEFI, we have to be careful
 239          * not to inadvertantly free memory we want to keep if there is
 240          * overlap at the kernel page size alignment. We do not want to
 241          * free is_reserve_region() memory nor the UEFI memmap itself.
 242          *
 243          * The memory map is sorted, so we keep track of the end of
 244          * any previous region we want to keep, remember any region
 245          * we want to free and defer freeing it until we encounter
 246          * the next region we want to keep. This way, before freeing
 247          * it, we can clip it as needed to avoid freeing memory we
 248          * want to keep for UEFI.
 249          */
 250
 251         keep_end = 0;
 252         free_start = 0;
 253
 254         for_each_efi_memory_desc(&memmap, md) {
 255                 u64 paddr, npages, size;
 256
 257                 if (is_reserve_region(md)) {
 258                         /*
 259                          * We don't want to free any memory from this region.
 260                          */
 261                         if (free_start) {
 262                                 /* adjust free_end then free region */
 263                                 if (free_end > md->phys_addr)
 264                                         free_end -= PAGE_SIZE;
 265                                 total_freed += free_region(free_start, free_end);
 266                                 free_start = 0;
 267                         }
 268                         keep_end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);
 269                         continue;
 270                 }
 271
 272                 if (md->type != EFI_BOOT_SERVICES_CODE &&
 273                     md->type != EFI_BOOT_SERVICES_DATA) {
 274                         /* no need to free this region */
 275                         continue;
 276                 }
 277
 278                 /*
 279                  * We want to free memory from this region.
 280                  */
 281                 paddr = md->phys_addr;
 282                 npages = md->num_pages;
 283                 memrange_efi_to_native(&paddr, &npages);
 284                 size = npages << PAGE_SHIFT;
 285
 286                 if (free_start) {
 287                         if (paddr <= free_end)
 288                                 free_end = paddr + size;
 289                         else {
 290                                 total_freed += free_region(free_start, free_end);
 291                                 free_start = paddr;
 292                                 free_end = paddr + size;
 293                         }
 294                 } else {
 295                         free_start = paddr;
 296                         free_end = paddr + size;
 297                 }
 298                 if (free_start < keep_end) {
 299                         free_start += PAGE_SIZE;
 300                         if (free_start >= free_end)
 301                                 free_start = 0;
 302                 }
 303         }
 304         if (free_start)
 305                 total_freed += free_region(free_start, free_end);
 306
 307         if (total_freed)
 308                 pr_info("Freed 0x%llx bytes of EFI boot services memory",
 309                         total_freed);
 310 }
 311
 312 void __init efi_init(void)
 313 {
 314         struct efi_fdt_params params;
 315
 316         /* Grab UEFI information placed in FDT by stub */
 317         if (!efi_get_fdt_params(&params, uefi_debug))
 318                 return;
 319
 320         efi_system_table = params.system_table;
 321
 322         memblock_reserve(params.mmap & PAGE_MASK,
 323                          PAGE_ALIGN(params.mmap_size + (params.mmap & ~PAGE_MASK)));
 324         memmap.phys_map = (void *)params.mmap;
 325         memmap.map = early_memremap(params.mmap, params.mmap_size);
 326         memmap.map_end = memmap.map + params.mmap_size;
 327         memmap.desc_size = params.desc_size;
 328         memmap.desc_version = params.desc_ver;
 329
 330         if (uefi_init() < 0)
 331                 return;
 332
 333         reserve_regions();
 334 }
 335
 336 void __init efi_idmap_init(void)
 337 {
 338         if (!efi_enabled(EFI_BOOT))
 339                 return;
 340
 341         /* boot time idmap_pg_dir is incomplete, so fill in missing parts */
 342         efi_setup_idmap();
 343 }
 344
 345 static int __init remap_region(efi_memory_desc_t *md, void **new)
 346 {
 347         u64 paddr, vaddr, npages, size;
 348
 349         paddr = md->phys_addr;
 350         npages = md->num_pages;
 351         memrange_efi_to_native(&paddr, &npages);
 352         size = npages << PAGE_SHIFT;
 353
 354         if (is_normal_ram(md))
 355                 vaddr = (__force u64)ioremap_cache(paddr, size);
 356         else
 357                 vaddr = (__force u64)ioremap(paddr, size);
 358
 359         if (!vaddr) {
 360                 pr_err("Unable to remap 0x%llx pages @ %p\n",
 361                        npages, (void *)paddr);
 362                 return 0;
 363         }
 364
 365         /* adjust for any rounding when EFI and system pagesize differs */
 366         md->virt_addr = vaddr + (md->phys_addr - paddr);
 367
 368         if (uefi_debug)
 369                 pr_info("  EFI remap 0x%012llx => %p\n",
 370                         md->phys_addr, (void *)md->virt_addr);
 371
 372         memcpy(*new, md, memmap.desc_size);
 373         *new += memmap.desc_size;
 374
 375         return 1;
 376 }
 377
 378 /*
 379  * Switch UEFI from an identity map to a kernel virtual map
 380  */
 381 static int __init arm64_enter_virtual_mode(void)
 382 {
 383         efi_memory_desc_t *md;
 384         phys_addr_t virtmap_phys;
 385         void *virtmap, *virt_md;
 386         efi_status_t status;
 387         u64 mapsize;
 388         int count = 0;
 389         unsigned long flags;
 390
 391         if (!efi_enabled(EFI_BOOT)) {
 392                 pr_info("EFI services will not be available.\n");
 393                 return -1;
 394         }
 395
 396         pr_info("Remapping and enabling EFI services.\n");
 397
 398         /* replace early memmap mapping with permanent mapping */
 399         mapsize = memmap.map_end - memmap.map;
 400         early_memunmap(memmap.map, mapsize);
 401         memmap.map = (__force void *)ioremap_cache((phys_addr_t)memmap.phys_map,
 402                                                    mapsize);
 403         memmap.map_end = memmap.map + mapsize;
 404
 405         efi.memmap = &memmap;
 406
 407         /* Map the runtime regions */
 408         virtmap = kmalloc(mapsize, GFP_KERNEL);
 409         if (!virtmap) {
 410                 pr_err("Failed to allocate EFI virtual memmap\n");
 411                 return -1;
 412         }
 413         virtmap_phys = virt_to_phys(virtmap);
 414         virt_md = virtmap;
 415
 416         for_each_efi_memory_desc(&memmap, md) {
 417                 if (!(md->attribute & EFI_MEMORY_RUNTIME))
 418                         continue;
 419                 if (!remap_region(md, &virt_md))
 420                         goto err_unmap;
 421                 ++count;
 422         }
 423
 424         efi.systab = (__force void *)efi_lookup_mapped_addr(efi_system_table);
 425         if (!efi.systab) {
 426                 /*
 427                  * If we have no virtual mapping for the System Table at this
 428                  * point, the memory map doesn't cover the physical offset where
 429                  * it resides. This means the System Table will be inaccessible
 430                  * to Runtime Services themselves once the virtual mapping is
 431                  * installed.
 432                  */
 433                 pr_err("Failed to remap EFI System Table -- buggy firmware?\n");
 434                 goto err_unmap;
 435         }
 436         set_bit(EFI_SYSTEM_TABLES, &efi.flags);
 437
 438         local_irq_save(flags);
 439         cpu_switch_mm(idmap_pg_dir, &init_mm);
 440
 441         /* Call SetVirtualAddressMap with the physical address of the map */
 442         runtime = efi.systab->runtime;
 443         efi.set_virtual_address_map = runtime->set_virtual_address_map;
 444
 445         status = efi.set_virtual_address_map(count * memmap.desc_size,
 446                                              memmap.desc_size,
 447                                              memmap.desc_version,
 448                                              (efi_memory_desc_t *)virtmap_phys);
 449         cpu_set_reserved_ttbr0();
 450         flush_tlb_all();
 451         local_irq_restore(flags);
 452
 453         kfree(virtmap);
 454
 455         free_boot_services();
 456
 457         if (status != EFI_SUCCESS) {
 458                 pr_err("Failed to set EFI virtual address map! [%lx]\n",
 459                         status);
 460                 return -1;
 461         }
 462
 463         /* Set up runtime services function pointers */
 464         runtime = efi.systab->runtime;
 465         efi_native_runtime_setup();
 466         set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 467
 468         efi.runtime_version = efi.systab->hdr.revision;
 469
 470         return 0;
 471
 472 err_unmap:
 473         /* unmap all mappings that succeeded: there are 'count' of those */
 474         for (virt_md = virtmap; count--; virt_md += memmap.desc_size) {
 475                 md = virt_md;
 476                 iounmap((__force void __iomem *)md->virt_addr);
 477         }
 478         kfree(virtmap);
 479         return -1;
 480 }
 481 early_initcall(arm64_enter_virtual_mode);