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                 retval = -EINVAL;
  94                 goto out;
  95         }
  96         if ((efi.systab->hdr.revision >> 16) < 2)
  97                 pr_warn("Warning: EFI system table version %d.%02d, expected 2.00 or greater\n",
  98                         efi.systab->hdr.revision >> 16,
  99                         efi.systab->hdr.revision & 0xffff);
 100
 101         /* Show what we know for posterity */
 102         c16 = early_memremap(efi.systab->fw_vendor,
 103                              sizeof(vendor));
 104         if (c16) {
 105                 for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
 106                         vendor[i] = c16[i];
 107                 vendor[i] = '\0';
 108                 early_memunmap(c16, sizeof(vendor));
 109         }
 110
 111         pr_info("EFI v%u.%.02u by %s\n",
 112                 efi.systab->hdr.revision >> 16,
 113                 efi.systab->hdr.revision & 0xffff, vendor);
 114
 115         retval = efi_config_init(NULL);
 116
 117 out:
 118         early_memunmap(efi.systab,  sizeof(efi_system_table_t));
 119         return retval;
 120 }
 121
 122 /*
 123  * Return true for RAM regions we want to permanently reserve.
 124  */
 125 static __init int is_reserve_region(efi_memory_desc_t *md)
 126 {
 127         switch (md->type) {
 128         case EFI_LOADER_CODE:
 129         case EFI_LOADER_DATA:
 130         case EFI_BOOT_SERVICES_CODE:
 131         case EFI_BOOT_SERVICES_DATA:
 132         case EFI_CONVENTIONAL_MEMORY:
 133                 return 0;
 134         default:
 135                 break;
 136         }
 137         return is_normal_ram(md);
 138 }
 139
 140 static __init void reserve_regions(void)
 141 {
 142         efi_memory_desc_t *md;
 143         u64 paddr, npages, size;
 144
 145         if (uefi_debug)
 146                 pr_info("Processing EFI memory map:\n");
 147
 148         for_each_efi_memory_desc(&memmap, md) {
 149                 paddr = md->phys_addr;
 150                 npages = md->num_pages;
 151
 152                 if (uefi_debug) {
 153                         char buf[64];
 154
 155                         pr_info("  0x%012llx-0x%012llx %s",
 156                                 paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
 157                                 efi_md_typeattr_format(buf, sizeof(buf), md));
 158                 }
 159
 160                 memrange_efi_to_native(&paddr, &npages);
 161                 size = npages << PAGE_SHIFT;
 162
 163                 if (is_normal_ram(md))
 164                         early_init_dt_add_memory_arch(paddr, size);
 165
 166                 if (is_reserve_region(md) ||
 167                     md->type == EFI_BOOT_SERVICES_CODE ||
 168                     md->type == EFI_BOOT_SERVICES_DATA) {
 169                         memblock_reserve(paddr, size);
 170                         if (uefi_debug)
 171                                 pr_cont("*");
 172                 }
 173
 174                 if (uefi_debug)
 175                         pr_cont("\n");
 176         }
 177
 178         set_bit(EFI_MEMMAP, &efi.flags);
 179 }
 180
 181
 182 static u64 __init free_one_region(u64 start, u64 end)
 183 {
 184         u64 size = end - start;
 185
 186         if (uefi_debug)
 187                 pr_info("  EFI freeing: 0x%012llx-0x%012llx\n", start, end - 1);
 188
 189         free_bootmem_late(start, size);
 190         return size;
 191 }
 192
 193 static u64 __init free_region(u64 start, u64 end)
 194 {
 195         u64 map_start, map_end, total = 0;
 196
 197         if (end <= start)
 198                 return total;
 199
 200         map_start = (u64)memmap.phys_map;
 201         map_end = PAGE_ALIGN(map_start + (memmap.map_end - memmap.map));
 202         map_start &= PAGE_MASK;
 203
 204         if (start < map_end && end > map_start) {
 205                 /* region overlaps UEFI memmap */
 206                 if (start < map_start)
 207                         total += free_one_region(start, map_start);
 208
 209                 if (map_end < end)
 210                         total += free_one_region(map_end, end);
 211         } else
 212                 total += free_one_region(start, end);
 213
 214         return total;
 215 }
 216
 217 static void __init free_boot_services(void)
 218 {
 219         u64 total_freed = 0;
 220         u64 keep_end, free_start, free_end;
 221         efi_memory_desc_t *md;
 222
 223         /*
 224          * If kernel uses larger pages than UEFI, we have to be careful
 225          * not to inadvertantly free memory we want to keep if there is
 226          * overlap at the kernel page size alignment. We do not want to
 227          * free is_reserve_region() memory nor the UEFI memmap itself.
 228          *
 229          * The memory map is sorted, so we keep track of the end of
 230          * any previous region we want to keep, remember any region
 231          * we want to free and defer freeing it until we encounter
 232          * the next region we want to keep. This way, before freeing
 233          * it, we can clip it as needed to avoid freeing memory we
 234          * want to keep for UEFI.
 235          */
 236
 237         keep_end = 0;
 238         free_start = 0;
 239
 240         for_each_efi_memory_desc(&memmap, md) {
 241                 u64 paddr, npages, size;
 242
 243                 if (is_reserve_region(md)) {
 244                         /*
 245                          * We don't want to free any memory from this region.
 246                          */
 247                         if (free_start) {
 248                                 /* adjust free_end then free region */
 249                                 if (free_end > md->phys_addr)
 250                                         free_end -= PAGE_SIZE;
 251                                 total_freed += free_region(free_start, free_end);
 252                                 free_start = 0;
 253                         }
 254                         keep_end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);
 255                         continue;
 256                 }
 257
 258                 if (md->type != EFI_BOOT_SERVICES_CODE &&
 259                     md->type != EFI_BOOT_SERVICES_DATA) {
 260                         /* no need to free this region */
 261                         continue;
 262                 }
 263
 264                 /*
 265                  * We want to free memory from this region.
 266                  */
 267                 paddr = md->phys_addr;
 268                 npages = md->num_pages;
 269                 memrange_efi_to_native(&paddr, &npages);
 270                 size = npages << PAGE_SHIFT;
 271
 272                 if (free_start) {
 273                         if (paddr <= free_end)
 274                                 free_end = paddr + size;
 275                         else {
 276                                 total_freed += free_region(free_start, free_end);
 277                                 free_start = paddr;
 278                                 free_end = paddr + size;
 279                         }
 280                 } else {
 281                         free_start = paddr;
 282                         free_end = paddr + size;
 283                 }
 284                 if (free_start < keep_end) {
 285                         free_start += PAGE_SIZE;
 286                         if (free_start >= free_end)
 287                                 free_start = 0;
 288                 }
 289         }
 290         if (free_start)
 291                 total_freed += free_region(free_start, free_end);
 292
 293         if (total_freed)
 294                 pr_info("Freed 0x%llx bytes of EFI boot services memory",
 295                         total_freed);
 296 }
 297
 298 void __init efi_init(void)
 299 {
 300         struct efi_fdt_params params;
 301
 302         /* Grab UEFI information placed in FDT by stub */
 303         if (!efi_get_fdt_params(&params, uefi_debug))
 304                 return;
 305
 306         efi_system_table = params.system_table;
 307
 308         memblock_reserve(params.mmap & PAGE_MASK,
 309                          PAGE_ALIGN(params.mmap_size + (params.mmap & ~PAGE_MASK)));
 310         memmap.phys_map = (void *)params.mmap;
 311         memmap.map = early_memremap(params.mmap, params.mmap_size);
 312         memmap.map_end = memmap.map + params.mmap_size;
 313         memmap.desc_size = params.desc_size;
 314         memmap.desc_version = params.desc_ver;
 315
 316         if (uefi_init() < 0)
 317                 return;
 318
 319         reserve_regions();
 320 }
 321
 322 void __init efi_idmap_init(void)
 323 {
 324         if (!efi_enabled(EFI_BOOT))
 325                 return;
 326
 327         /* boot time idmap_pg_dir is incomplete, so fill in missing parts */
 328         efi_setup_idmap();
 329         early_memunmap(memmap.map, memmap.map_end - memmap.map);
 330 }
 331
 332 static int __init remap_region(efi_memory_desc_t *md, void **new)
 333 {
 334         u64 paddr, vaddr, npages, size;
 335
 336         paddr = md->phys_addr;
 337         npages = md->num_pages;
 338         memrange_efi_to_native(&paddr, &npages);
 339         size = npages << PAGE_SHIFT;
 340
 341         if (is_normal_ram(md))
 342                 vaddr = (__force u64)ioremap_cache(paddr, size);
 343         else
 344                 vaddr = (__force u64)ioremap(paddr, size);
 345
 346         if (!vaddr) {
 347                 pr_err("Unable to remap 0x%llx pages @ %p\n",
 348                        npages, (void *)paddr);
 349                 return 0;
 350         }
 351
 352         /* adjust for any rounding when EFI and system pagesize differs */
 353         md->virt_addr = vaddr + (md->phys_addr - paddr);
 354
 355         if (uefi_debug)
 356                 pr_info("  EFI remap 0x%012llx => %p\n",
 357                         md->phys_addr, (void *)md->virt_addr);
 358
 359         memcpy(*new, md, memmap.desc_size);
 360         *new += memmap.desc_size;
 361
 362         return 1;
 363 }
 364
 365 /*
 366  * Switch UEFI from an identity map to a kernel virtual map
 367  */
 368 static int __init arm64_enter_virtual_mode(void)
 369 {
 370         efi_memory_desc_t *md;
 371         phys_addr_t virtmap_phys;
 372         void *virtmap, *virt_md;
 373         efi_status_t status;
 374         u64 mapsize;
 375         int count = 0;
 376         unsigned long flags;
 377
 378         if (!efi_enabled(EFI_BOOT)) {
 379                 pr_info("EFI services will not be available.\n");
 380                 return -1;
 381         }
 382
 383         mapsize = memmap.map_end - memmap.map;
 384
 385         if (efi_runtime_disabled()) {
 386                 pr_info("EFI runtime services will be disabled.\n");
 387                 return -1;
 388         }
 389
 390         pr_info("Remapping and enabling EFI services.\n");
 391         /* replace early memmap mapping with permanent mapping */
 392         memmap.map = (__force void *)ioremap_cache((phys_addr_t)memmap.phys_map,
 393                                                    mapsize);
 394         memmap.map_end = memmap.map + mapsize;
 395
 396         efi.memmap = &memmap;
 397
 398         /* Map the runtime regions */
 399         virtmap = kmalloc(mapsize, GFP_KERNEL);
 400         if (!virtmap) {
 401                 pr_err("Failed to allocate EFI virtual memmap\n");
 402                 return -1;
 403         }
 404         virtmap_phys = virt_to_phys(virtmap);
 405         virt_md = virtmap;
 406
 407         for_each_efi_memory_desc(&memmap, md) {
 408                 if (!(md->attribute & EFI_MEMORY_RUNTIME))
 409                         continue;
 410                 if (!remap_region(md, &virt_md))
 411                         goto err_unmap;
 412                 ++count;
 413         }
 414
 415         efi.systab = (__force void *)efi_lookup_mapped_addr(efi_system_table);
 416         if (!efi.systab) {
 417                 /*
 418                  * If we have no virtual mapping for the System Table at this
 419                  * point, the memory map doesn't cover the physical offset where
 420                  * it resides. This means the System Table will be inaccessible
 421                  * to Runtime Services themselves once the virtual mapping is
 422                  * installed.
 423                  */
 424                 pr_err("Failed to remap EFI System Table -- buggy firmware?\n");
 425                 goto err_unmap;
 426         }
 427         set_bit(EFI_SYSTEM_TABLES, &efi.flags);
 428
 429         local_irq_save(flags);
 430         cpu_switch_mm(idmap_pg_dir, &init_mm);
 431
 432         /* Call SetVirtualAddressMap with the physical address of the map */
 433         runtime = efi.systab->runtime;
 434         efi.set_virtual_address_map = runtime->set_virtual_address_map;
 435
 436         status = efi.set_virtual_address_map(count * memmap.desc_size,
 437                                              memmap.desc_size,
 438                                              memmap.desc_version,
 439                                              (efi_memory_desc_t *)virtmap_phys);
 440         cpu_set_reserved_ttbr0();
 441         flush_tlb_all();
 442         local_irq_restore(flags);
 443
 444         kfree(virtmap);
 445
 446         free_boot_services();
 447
 448         if (status != EFI_SUCCESS) {
 449                 pr_err("Failed to set EFI virtual address map! [%lx]\n",
 450                         status);
 451                 return -1;
 452         }
 453
 454         /* Set up runtime services function pointers */
 455         runtime = efi.systab->runtime;
 456         efi_native_runtime_setup();
 457         set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 458
 459         efi.runtime_version = efi.systab->hdr.revision;
 460
 461         return 0;
 462
 463 err_unmap:
 464         /* unmap all mappings that succeeded: there are 'count' of those */
 465         for (virt_md = virtmap; count--; virt_md += memmap.desc_size) {
 466                 md = virt_md;
 467                 iounmap((__force void __iomem *)md->virt_addr);
 468         }
 469         kfree(virtmap);
 470         return -1;
 471 }
 472 early_initcall(arm64_enter_virtual_mode);
 473
 474 static int __init arm64_dmi_init(void)
 475 {
 476         /*
 477          * On arm64, DMI depends on UEFI, and dmi_scan_machine() needs to
 478          * be called early because dmi_id_init(), which is an arch_initcall
 479          * itself, depends on dmi_scan_machine() having been called already.
 480          */
 481         dmi_scan_machine();
 482         if (dmi_available)
 483                 dmi_set_dump_stack_arch_desc();
 484         return 0;
 485 }
 486 core_initcall(arm64_dmi_init);