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 /*
 124  * Return true for RAM regions we want to permanently reserve.
 125  */
 126 static __init int is_reserve_region(efi_memory_desc_t *md)
 127 {
 128         if (!is_normal_ram(md))
 129                 return 0;
 130
 131         if (md->attribute & EFI_MEMORY_RUNTIME)
 132                 return 1;
 133
 134         if (md->type == EFI_ACPI_RECLAIM_MEMORY ||
 135             md->type == EFI_RESERVED_TYPE)
 136                 return 1;
 137
 138         return 0;
 139 }
 140
 141 static __init void reserve_regions(void)
 142 {
 143         efi_memory_desc_t *md;
 144         u64 paddr, npages, size;
 145
 146         if (uefi_debug)
 147                 pr_info("Processing EFI memory map:\n");
 148
 149         for_each_efi_memory_desc(&memmap, md) {
 150                 paddr = md->phys_addr;
 151                 npages = md->num_pages;
 152
 153                 if (uefi_debug) {
 154                         char buf[64];
 155
 156                         pr_info("  0x%012llx-0x%012llx %s",
 157                                 paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
 158                                 efi_md_typeattr_format(buf, sizeof(buf), md));
 159                 }
 160
 161                 memrange_efi_to_native(&paddr, &npages);
 162                 size = npages << PAGE_SHIFT;
 163
 164                 if (is_normal_ram(md))
 165                         early_init_dt_add_memory_arch(paddr, size);
 166
 167                 if (is_reserve_region(md) ||
 168                     md->type == EFI_BOOT_SERVICES_CODE ||
 169                     md->type == EFI_BOOT_SERVICES_DATA) {
 170                         memblock_reserve(paddr, size);
 171                         if (uefi_debug)
 172                                 pr_cont("*");
 173                 }
 174
 175                 if (uefi_debug)
 176                         pr_cont("\n");
 177         }
 178
 179         set_bit(EFI_MEMMAP, &efi.flags);
 180 }
 181
 182
 183 static u64 __init free_one_region(u64 start, u64 end)
 184 {
 185         u64 size = end - start;
 186
 187         if (uefi_debug)
 188                 pr_info("  EFI freeing: 0x%012llx-0x%012llx\n", start, end - 1);
 189
 190         free_bootmem_late(start, size);
 191         return size;
 192 }
 193
 194 static u64 __init free_region(u64 start, u64 end)
 195 {
 196         u64 map_start, map_end, total = 0;
 197
 198         if (end <= start)
 199                 return total;
 200
 201         map_start = (u64)memmap.phys_map;
 202         map_end = PAGE_ALIGN(map_start + (memmap.map_end - memmap.map));
 203         map_start &= PAGE_MASK;
 204
 205         if (start < map_end && end > map_start) {
 206                 /* region overlaps UEFI memmap */
 207                 if (start < map_start)
 208                         total += free_one_region(start, map_start);
 209
 210                 if (map_end < end)
 211                         total += free_one_region(map_end, end);
 212         } else
 213                 total += free_one_region(start, end);
 214
 215         return total;
 216 }
 217
 218 static void __init free_boot_services(void)
 219 {
 220         u64 total_freed = 0;
 221         u64 keep_end, free_start, free_end;
 222         efi_memory_desc_t *md;
 223
 224         /*
 225          * If kernel uses larger pages than UEFI, we have to be careful
 226          * not to inadvertantly free memory we want to keep if there is
 227          * overlap at the kernel page size alignment. We do not want to
 228          * free is_reserve_region() memory nor the UEFI memmap itself.
 229          *
 230          * The memory map is sorted, so we keep track of the end of
 231          * any previous region we want to keep, remember any region
 232          * we want to free and defer freeing it until we encounter
 233          * the next region we want to keep. This way, before freeing
 234          * it, we can clip it as needed to avoid freeing memory we
 235          * want to keep for UEFI.
 236          */
 237
 238         keep_end = 0;
 239         free_start = 0;
 240
 241         for_each_efi_memory_desc(&memmap, md) {
 242                 u64 paddr, npages, size;
 243
 244                 if (is_reserve_region(md)) {
 245                         /*
 246                          * We don't want to free any memory from this region.
 247                          */
 248                         if (free_start) {
 249                                 /* adjust free_end then free region */
 250                                 if (free_end > md->phys_addr)
 251                                         free_end -= PAGE_SIZE;
 252                                 total_freed += free_region(free_start, free_end);
 253                                 free_start = 0;
 254                         }
 255                         keep_end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);
 256                         continue;
 257                 }
 258
 259                 if (md->type != EFI_BOOT_SERVICES_CODE &&
 260                     md->type != EFI_BOOT_SERVICES_DATA) {
 261                         /* no need to free this region */
 262                         continue;
 263                 }
 264
 265                 /*
 266                  * We want to free memory from this region.
 267                  */
 268                 paddr = md->phys_addr;
 269                 npages = md->num_pages;
 270                 memrange_efi_to_native(&paddr, &npages);
 271                 size = npages << PAGE_SHIFT;
 272
 273                 if (free_start) {
 274                         if (paddr <= free_end)
 275                                 free_end = paddr + size;
 276                         else {
 277                                 total_freed += free_region(free_start, free_end);
 278                                 free_start = paddr;
 279                                 free_end = paddr + size;
 280                         }
 281                 } else {
 282                         free_start = paddr;
 283                         free_end = paddr + size;
 284                 }
 285                 if (free_start < keep_end) {
 286                         free_start += PAGE_SIZE;
 287                         if (free_start >= free_end)
 288                                 free_start = 0;
 289                 }
 290         }
 291         if (free_start)
 292                 total_freed += free_region(free_start, free_end);
 293
 294         if (total_freed)
 295                 pr_info("Freed 0x%llx bytes of EFI boot services memory",
 296                         total_freed);
 297 }
 298
 299 void __init efi_init(void)
 300 {
 301         struct efi_fdt_params params;
 302
 303         /* Grab UEFI information placed in FDT by stub */
 304         if (!efi_get_fdt_params(&params, uefi_debug))
 305                 return;
 306
 307         efi_system_table = params.system_table;
 308
 309         memblock_reserve(params.mmap & PAGE_MASK,
 310                          PAGE_ALIGN(params.mmap_size + (params.mmap & ~PAGE_MASK)));
 311         memmap.phys_map = (void *)params.mmap;
 312         memmap.map = early_memremap(params.mmap, params.mmap_size);
 313         memmap.map_end = memmap.map + params.mmap_size;
 314         memmap.desc_size = params.desc_size;
 315         memmap.desc_version = params.desc_ver;
 316
 317         if (uefi_init() < 0)
 318                 return;
 319
 320         reserve_regions();
 321 }
 322
 323 void __init efi_idmap_init(void)
 324 {
 325         if (!efi_enabled(EFI_BOOT))
 326                 return;
 327
 328         /* boot time idmap_pg_dir is incomplete, so fill in missing parts */
 329         efi_setup_idmap();
 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         early_memunmap(memmap.map, mapsize);
 385
 386         if (efi_runtime_disabled()) {
 387                 pr_info("EFI runtime services will be disabled.\n");
 388                 return -1;
 389         }
 390
 391         pr_info("Remapping and enabling EFI services.\n");
 392         /* replace early memmap mapping with permanent mapping */
 393         memmap.map = (__force void *)ioremap_cache((phys_addr_t)memmap.phys_map,
 394                                                    mapsize);
 395         memmap.map_end = memmap.map + mapsize;
 396
 397         efi.memmap = &memmap;
 398
 399         /* Map the runtime regions */
 400         virtmap = kmalloc(mapsize, GFP_KERNEL);
 401         if (!virtmap) {
 402                 pr_err("Failed to allocate EFI virtual memmap\n");
 403                 return -1;
 404         }
 405         virtmap_phys = virt_to_phys(virtmap);
 406         virt_md = virtmap;
 407
 408         for_each_efi_memory_desc(&memmap, md) {
 409                 if (!(md->attribute & EFI_MEMORY_RUNTIME))
 410                         continue;
 411                 if (!remap_region(md, &virt_md))
 412                         goto err_unmap;
 413                 ++count;
 414         }
 415
 416         efi.systab = (__force void *)efi_lookup_mapped_addr(efi_system_table);
 417         if (!efi.systab) {
 418                 /*
 419                  * If we have no virtual mapping for the System Table at this
 420                  * point, the memory map doesn't cover the physical offset where
 421                  * it resides. This means the System Table will be inaccessible
 422                  * to Runtime Services themselves once the virtual mapping is
 423                  * installed.
 424                  */
 425                 pr_err("Failed to remap EFI System Table -- buggy firmware?\n");
 426                 goto err_unmap;
 427         }
 428         set_bit(EFI_SYSTEM_TABLES, &efi.flags);
 429
 430         local_irq_save(flags);
 431         cpu_switch_mm(idmap_pg_dir, &init_mm);
 432
 433         /* Call SetVirtualAddressMap with the physical address of the map */
 434         runtime = efi.systab->runtime;
 435         efi.set_virtual_address_map = runtime->set_virtual_address_map;
 436
 437         status = efi.set_virtual_address_map(count * memmap.desc_size,
 438                                              memmap.desc_size,
 439                                              memmap.desc_version,
 440                                              (efi_memory_desc_t *)virtmap_phys);
 441         cpu_set_reserved_ttbr0();
 442         flush_tlb_all();
 443         local_irq_restore(flags);
 444
 445         kfree(virtmap);
 446
 447         free_boot_services();
 448
 449         if (status != EFI_SUCCESS) {
 450                 pr_err("Failed to set EFI virtual address map! [%lx]\n",
 451                         status);
 452                 return -1;
 453         }
 454
 455         /* Set up runtime services function pointers */
 456         runtime = efi.systab->runtime;
 457         efi_native_runtime_setup();
 458         set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 459
 460         efi.runtime_version = efi.systab->hdr.revision;
 461
 462         return 0;
 463
 464 err_unmap:
 465         /* unmap all mappings that succeeded: there are 'count' of those */
 466         for (virt_md = virtmap; count--; virt_md += memmap.desc_size) {
 467                 md = virt_md;
 468                 iounmap((__force void __iomem *)md->virt_addr);
 469         }
 470         kfree(virtmap);
 471         return -1;
 472 }
 473 early_initcall(arm64_enter_virtual_mode);