linux/drivers/firmware/efi/libstub/efi-stub-helper.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Helper functions used by the EFI stub on multiple
   4 * architectures. This should be #included by the EFI stub
   5 * implementation files.
   6 *
   7 * Copyright 2011 Intel Corporation; author Matt Fleming
   8 */
   9
  10#include <linux/efi.h>
  11#include <asm/efi.h>
  12
  13#include "efistub.h"
  14
  15/*
  16 * Some firmware implementations have problems reading files in one go.
  17 * A read chunk size of 1MB seems to work for most platforms.
  18 *
  19 * Unfortunately, reading files in chunks triggers *other* bugs on some
  20 * platforms, so we provide a way to disable this workaround, which can
  21 * be done by passing "efi=nochunk" on the EFI boot stub command line.
  22 *
  23 * If you experience issues with initrd images being corrupt it's worth
  24 * trying efi=nochunk, but chunking is enabled by default because there
  25 * are far more machines that require the workaround than those that
  26 * break with it enabled.
  27 */
  28#define EFI_READ_CHUNK_SIZE     (1024 * 1024)
  29
  30static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;
  31
  32static int __section(.data) __nokaslr;
  33static int __section(.data) __quiet;
  34static int __section(.data) __novamap;
  35
  36int __pure nokaslr(void)
  37{
  38        return __nokaslr;
  39}
  40int __pure is_quiet(void)
  41{
  42        return __quiet;
  43}
  44int __pure novamap(void)
  45{
  46        return __novamap;
  47}
  48
  49#define EFI_MMAP_NR_SLACK_SLOTS 8
  50
  51struct file_info {
  52        efi_file_handle_t *handle;
  53        u64 size;
  54};
  55
  56void efi_printk(efi_system_table_t *sys_table_arg, char *str)
  57{
  58        char *s8;
  59
  60        for (s8 = str; *s8; s8++) {
  61                efi_char16_t ch[2] = { 0 };
  62
  63                ch[0] = *s8;
  64                if (*s8 == '\n') {
  65                        efi_char16_t nl[2] = { '\r', 0 };
  66                        efi_char16_printk(sys_table_arg, nl);
  67                }
  68
  69                efi_char16_printk(sys_table_arg, ch);
  70        }
  71}
  72
  73static inline bool mmap_has_headroom(unsigned long buff_size,
  74                                     unsigned long map_size,
  75                                     unsigned long desc_size)
  76{
  77        unsigned long slack = buff_size - map_size;
  78
  79        return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS;
  80}
  81
  82efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
  83                                struct efi_boot_memmap *map)
  84{
  85        efi_memory_desc_t *m = NULL;
  86        efi_status_t status;
  87        unsigned long key;
  88        u32 desc_version;
  89
  90        *map->desc_size =       sizeof(*m);
  91        *map->map_size =        *map->desc_size * 32;
  92        *map->buff_size =       *map->map_size;
  93again:
  94        status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
  95                                *map->map_size, (void **)&m);
  96        if (status != EFI_SUCCESS)
  97                goto fail;
  98
  99        *map->desc_size = 0;
 100        key = 0;
 101        status = efi_call_early(get_memory_map, map->map_size, m,
 102                                &key, map->desc_size, &desc_version);
 103        if (status == EFI_BUFFER_TOO_SMALL ||
 104            !mmap_has_headroom(*map->buff_size, *map->map_size,
 105                               *map->desc_size)) {
 106                efi_call_early(free_pool, m);
 107                /*
 108                 * Make sure there is some entries of headroom so that the
 109                 * buffer can be reused for a new map after allocations are
 110                 * no longer permitted.  Its unlikely that the map will grow to
 111                 * exceed this headroom once we are ready to trigger
 112                 * ExitBootServices()
 113                 */
 114                *map->map_size += *map->desc_size * EFI_MMAP_NR_SLACK_SLOTS;
 115                *map->buff_size = *map->map_size;
 116                goto again;
 117        }
 118
 119        if (status != EFI_SUCCESS)
 120                efi_call_early(free_pool, m);
 121
 122        if (map->key_ptr && status == EFI_SUCCESS)
 123                *map->key_ptr = key;
 124        if (map->desc_ver && status == EFI_SUCCESS)
 125                *map->desc_ver = desc_version;
 126
 127fail:
 128        *map->map = m;
 129        return status;
 130}
 131
 132
 133unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
 134{
 135        efi_status_t status;
 136        unsigned long map_size, buff_size;
 137        unsigned long membase  = EFI_ERROR;
 138        struct efi_memory_map map;
 139        efi_memory_desc_t *md;
 140        struct efi_boot_memmap boot_map;
 141
 142        boot_map.map =          (efi_memory_desc_t **)&map.map;
 143        boot_map.map_size =     &map_size;
 144        boot_map.desc_size =    &map.desc_size;
 145        boot_map.desc_ver =     NULL;
 146        boot_map.key_ptr =      NULL;
 147        boot_map.buff_size =    &buff_size;
 148
 149        status = efi_get_memory_map(sys_table_arg, &boot_map);
 150        if (status != EFI_SUCCESS)
 151                return membase;
 152
 153        map.map_end = map.map + map_size;
 154
 155        for_each_efi_memory_desc_in_map(&map, md) {
 156                if (md->attribute & EFI_MEMORY_WB) {
 157                        if (membase > md->phys_addr)
 158                                membase = md->phys_addr;
 159                }
 160        }
 161
 162        efi_call_early(free_pool, map.map);
 163
 164        return membase;
 165}
 166
 167/*
 168 * Allocate at the highest possible address that is not above 'max'.
 169 */
 170efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
 171                            unsigned long size, unsigned long align,
 172                            unsigned long *addr, unsigned long max)
 173{
 174        unsigned long map_size, desc_size, buff_size;
 175        efi_memory_desc_t *map;
 176        efi_status_t status;
 177        unsigned long nr_pages;
 178        u64 max_addr = 0;
 179        int i;
 180        struct efi_boot_memmap boot_map;
 181
 182        boot_map.map =          &map;
 183        boot_map.map_size =     &map_size;
 184        boot_map.desc_size =    &desc_size;
 185        boot_map.desc_ver =     NULL;
 186        boot_map.key_ptr =      NULL;
 187        boot_map.buff_size =    &buff_size;
 188
 189        status = efi_get_memory_map(sys_table_arg, &boot_map);
 190        if (status != EFI_SUCCESS)
 191                goto fail;
 192
 193        /*
 194         * Enforce minimum alignment that EFI or Linux requires when
 195         * requesting a specific address.  We are doing page-based (or
 196         * larger) allocations, and both the address and size must meet
 197         * alignment constraints.
 198         */
 199        if (align < EFI_ALLOC_ALIGN)
 200                align = EFI_ALLOC_ALIGN;
 201
 202        size = round_up(size, EFI_ALLOC_ALIGN);
 203        nr_pages = size / EFI_PAGE_SIZE;
 204again:
 205        for (i = 0; i < map_size / desc_size; i++) {
 206                efi_memory_desc_t *desc;
 207                unsigned long m = (unsigned long)map;
 208                u64 start, end;
 209
 210                desc = efi_early_memdesc_ptr(m, desc_size, i);
 211                if (desc->type != EFI_CONVENTIONAL_MEMORY)
 212                        continue;
 213
 214                if (desc->num_pages < nr_pages)
 215                        continue;
 216
 217                start = desc->phys_addr;
 218                end = start + desc->num_pages * EFI_PAGE_SIZE;
 219
 220                if (end > max)
 221                        end = max;
 222
 223                if ((start + size) > end)
 224                        continue;
 225
 226                if (round_down(end - size, align) < start)
 227                        continue;
 228
 229                start = round_down(end - size, align);
 230
 231                /*
 232                 * Don't allocate at 0x0. It will confuse code that
 233                 * checks pointers against NULL.
 234                 */
 235                if (start == 0x0)
 236                        continue;
 237
 238                if (start > max_addr)
 239                        max_addr = start;
 240        }
 241
 242        if (!max_addr)
 243                status = EFI_NOT_FOUND;
 244        else {
 245                status = efi_call_early(allocate_pages,
 246                                        EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 247                                        nr_pages, &max_addr);
 248                if (status != EFI_SUCCESS) {
 249                        max = max_addr;
 250                        max_addr = 0;
 251                        goto again;
 252                }
 253
 254                *addr = max_addr;
 255        }
 256
 257        efi_call_early(free_pool, map);
 258fail:
 259        return status;
 260}
 261
 262/*
 263 * Allocate at the lowest possible address that is not below 'min'.
 264 */
 265efi_status_t efi_low_alloc_above(efi_system_table_t *sys_table_arg,
 266                                 unsigned long size, unsigned long align,
 267                                 unsigned long *addr, unsigned long min)
 268{
 269        unsigned long map_size, desc_size, buff_size;
 270        efi_memory_desc_t *map;
 271        efi_status_t status;
 272        unsigned long nr_pages;
 273        int i;
 274        struct efi_boot_memmap boot_map;
 275
 276        boot_map.map =          &map;
 277        boot_map.map_size =     &map_size;
 278        boot_map.desc_size =    &desc_size;
 279        boot_map.desc_ver =     NULL;
 280        boot_map.key_ptr =      NULL;
 281        boot_map.buff_size =    &buff_size;
 282
 283        status = efi_get_memory_map(sys_table_arg, &boot_map);
 284        if (status != EFI_SUCCESS)
 285                goto fail;
 286
 287        /*
 288         * Enforce minimum alignment that EFI or Linux requires when
 289         * requesting a specific address.  We are doing page-based (or
 290         * larger) allocations, and both the address and size must meet
 291         * alignment constraints.
 292         */
 293        if (align < EFI_ALLOC_ALIGN)
 294                align = EFI_ALLOC_ALIGN;
 295
 296        size = round_up(size, EFI_ALLOC_ALIGN);
 297        nr_pages = size / EFI_PAGE_SIZE;
 298        for (i = 0; i < map_size / desc_size; i++) {
 299                efi_memory_desc_t *desc;
 300                unsigned long m = (unsigned long)map;
 301                u64 start, end;
 302
 303                desc = efi_early_memdesc_ptr(m, desc_size, i);
 304
 305                if (desc->type != EFI_CONVENTIONAL_MEMORY)
 306                        continue;
 307
 308                if (desc->num_pages < nr_pages)
 309                        continue;
 310
 311                start = desc->phys_addr;
 312                end = start + desc->num_pages * EFI_PAGE_SIZE;
 313
 314                if (start < min)
 315                        start = min;
 316
 317                start = round_up(start, align);
 318                if ((start + size) > end)
 319                        continue;
 320
 321                status = efi_call_early(allocate_pages,
 322                                        EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 323                                        nr_pages, &start);
 324                if (status == EFI_SUCCESS) {
 325                        *addr = start;
 326                        break;
 327                }
 328        }
 329
 330        if (i == map_size / desc_size)
 331                status = EFI_NOT_FOUND;
 332
 333        efi_call_early(free_pool, map);
 334fail:
 335        return status;
 336}
 337
 338void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
 339              unsigned long addr)
 340{
 341        unsigned long nr_pages;
 342
 343        if (!size)
 344                return;
 345
 346        nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
 347        efi_call_early(free_pages, addr, nr_pages);
 348}
 349
 350static efi_status_t efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
 351                                  efi_char16_t *filename_16, void **handle,
 352                                  u64 *file_sz)
 353{
 354        efi_file_handle_t *h, *fh = __fh;
 355        efi_file_info_t *info;
 356        efi_status_t status;
 357        efi_guid_t info_guid = EFI_FILE_INFO_ID;
 358        unsigned long info_sz;
 359
 360        status = efi_call_proto(efi_file_handle, open, fh, &h, filename_16,
 361                                EFI_FILE_MODE_READ, (u64)0);
 362        if (status != EFI_SUCCESS) {
 363                efi_printk(sys_table_arg, "Failed to open file: ");
 364                efi_char16_printk(sys_table_arg, filename_16);
 365                efi_printk(sys_table_arg, "\n");
 366                return status;
 367        }
 368
 369        *handle = h;
 370
 371        info_sz = 0;
 372        status = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
 373                                &info_sz, NULL);
 374        if (status != EFI_BUFFER_TOO_SMALL) {
 375                efi_printk(sys_table_arg, "Failed to get file info size\n");
 376                return status;
 377        }
 378
 379grow:
 380        status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
 381                                info_sz, (void **)&info);
 382        if (status != EFI_SUCCESS) {
 383                efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
 384                return status;
 385        }
 386
 387        status = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
 388                                &info_sz, info);
 389        if (status == EFI_BUFFER_TOO_SMALL) {
 390                efi_call_early(free_pool, info);
 391                goto grow;
 392        }
 393
 394        *file_sz = info->file_size;
 395        efi_call_early(free_pool, info);
 396
 397        if (status != EFI_SUCCESS)
 398                efi_printk(sys_table_arg, "Failed to get initrd info\n");
 399
 400        return status;
 401}
 402
 403static efi_status_t efi_file_read(void *handle, unsigned long *size, void *addr)
 404{
 405        return efi_call_proto(efi_file_handle, read, handle, size, addr);
 406}
 407
 408static efi_status_t efi_file_close(void *handle)
 409{
 410        return efi_call_proto(efi_file_handle, close, handle);
 411}
 412
 413static efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
 414                                    efi_loaded_image_t *image,
 415                                    efi_file_handle_t **__fh)
 416{
 417        efi_file_io_interface_t *io;
 418        efi_file_handle_t *fh;
 419        efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
 420        efi_status_t status;
 421        void *handle = (void *)(unsigned long)efi_table_attr(efi_loaded_image,
 422                                                             device_handle,
 423                                                             image);
 424
 425        status = efi_call_early(handle_protocol, handle,
 426                                &fs_proto, (void **)&io);
 427        if (status != EFI_SUCCESS) {
 428                efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
 429                return status;
 430        }
 431
 432        status = efi_call_proto(efi_file_io_interface, open_volume, io, &fh);
 433        if (status != EFI_SUCCESS)
 434                efi_printk(sys_table_arg, "Failed to open volume\n");
 435        else
 436                *__fh = fh;
 437
 438        return status;
 439}
 440
 441/*
 442 * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
 443 * option, e.g. efi=nochunk.
 444 *
 445 * It should be noted that efi= is parsed in two very different
 446 * environments, first in the early boot environment of the EFI boot
 447 * stub, and subsequently during the kernel boot.
 448 */
 449efi_status_t efi_parse_options(char const *cmdline)
 450{
 451        char *str;
 452
 453        str = strstr(cmdline, "nokaslr");
 454        if (str == cmdline || (str && str > cmdline && *(str - 1) == ' '))
 455                __nokaslr = 1;
 456
 457        str = strstr(cmdline, "quiet");
 458        if (str == cmdline || (str && str > cmdline && *(str - 1) == ' '))
 459                __quiet = 1;
 460
 461        /*
 462         * If no EFI parameters were specified on the cmdline we've got
 463         * nothing to do.
 464         */
 465        str = strstr(cmdline, "efi=");
 466        if (!str)
 467                return EFI_SUCCESS;
 468
 469        /* Skip ahead to first argument */
 470        str += strlen("efi=");
 471
 472        /*
 473         * Remember, because efi= is also used by the kernel we need to
 474         * skip over arguments we don't understand.
 475         */
 476        while (*str && *str != ' ') {
 477                if (!strncmp(str, "nochunk", 7)) {
 478                        str += strlen("nochunk");
 479                        __chunk_size = -1UL;
 480                }
 481
 482                if (!strncmp(str, "novamap", 7)) {
 483                        str += strlen("novamap");
 484                        __novamap = 1;
 485                }
 486
 487                /* Group words together, delimited by "," */
 488                while (*str && *str != ' ' && *str != ',')
 489                        str++;
 490
 491                if (*str == ',')
 492                        str++;
 493        }
 494
 495        return EFI_SUCCESS;
 496}
 497
 498/*
 499 * Check the cmdline for a LILO-style file= arguments.
 500 *
 501 * We only support loading a file from the same filesystem as
 502 * the kernel image.
 503 */
 504efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 505                                  efi_loaded_image_t *image,
 506                                  char *cmd_line, char *option_string,
 507                                  unsigned long max_addr,
 508                                  unsigned long *load_addr,
 509                                  unsigned long *load_size)
 510{
 511        struct file_info *files;
 512        unsigned long file_addr;
 513        u64 file_size_total;
 514        efi_file_handle_t *fh = NULL;
 515        efi_status_t status;
 516        int nr_files;
 517        char *str;
 518        int i, j, k;
 519
 520        file_addr = 0;
 521        file_size_total = 0;
 522
 523        str = cmd_line;
 524
 525        j = 0;                  /* See close_handles */
 526
 527        if (!load_addr || !load_size)
 528                return EFI_INVALID_PARAMETER;
 529
 530        *load_addr = 0;
 531        *load_size = 0;
 532
 533        if (!str || !*str)
 534                return EFI_SUCCESS;
 535
 536        for (nr_files = 0; *str; nr_files++) {
 537                str = strstr(str, option_string);
 538                if (!str)
 539                        break;
 540
 541                str += strlen(option_string);
 542
 543                /* Skip any leading slashes */
 544                while (*str == '/' || *str == '\\')
 545                        str++;
 546
 547                while (*str && *str != ' ' && *str != '\n')
 548                        str++;
 549        }
 550
 551        if (!nr_files)
 552                return EFI_SUCCESS;
 553
 554        status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
 555                                nr_files * sizeof(*files), (void **)&files);
 556        if (status != EFI_SUCCESS) {
 557                pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
 558                goto fail;
 559        }
 560
 561        str = cmd_line;
 562        for (i = 0; i < nr_files; i++) {
 563                struct file_info *file;
 564                efi_char16_t filename_16[256];
 565                efi_char16_t *p;
 566
 567                str = strstr(str, option_string);
 568                if (!str)
 569                        break;
 570
 571                str += strlen(option_string);
 572
 573                file = &files[i];
 574                p = filename_16;
 575
 576                /* Skip any leading slashes */
 577                while (*str == '/' || *str == '\\')
 578                        str++;
 579
 580                while (*str && *str != ' ' && *str != '\n') {
 581                        if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
 582                                break;
 583
 584                        if (*str == '/') {
 585                                *p++ = '\\';
 586                                str++;
 587                        } else {
 588                                *p++ = *str++;
 589                        }
 590                }
 591
 592                *p = '\0';
 593
 594                /* Only open the volume once. */
 595                if (!i) {
 596                        status = efi_open_volume(sys_table_arg, image, &fh);
 597                        if (status != EFI_SUCCESS)
 598                                goto free_files;
 599                }
 600
 601                status = efi_file_size(sys_table_arg, fh, filename_16,
 602                                       (void **)&file->handle, &file->size);
 603                if (status != EFI_SUCCESS)
 604                        goto close_handles;
 605
 606                file_size_total += file->size;
 607        }
 608
 609        if (file_size_total) {
 610                unsigned long addr;
 611
 612                /*
 613                 * Multiple files need to be at consecutive addresses in memory,
 614                 * so allocate enough memory for all the files.  This is used
 615                 * for loading multiple files.
 616                 */
 617                status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
 618                                    &file_addr, max_addr);
 619                if (status != EFI_SUCCESS) {
 620                        pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
 621                        goto close_handles;
 622                }
 623
 624                /* We've run out of free low memory. */
 625                if (file_addr > max_addr) {
 626                        pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
 627                        status = EFI_INVALID_PARAMETER;
 628                        goto free_file_total;
 629                }
 630
 631                addr = file_addr;
 632                for (j = 0; j < nr_files; j++) {
 633                        unsigned long size;
 634
 635                        size = files[j].size;
 636                        while (size) {
 637                                unsigned long chunksize;
 638
 639                                if (IS_ENABLED(CONFIG_X86) && size > __chunk_size)
 640                                        chunksize = __chunk_size;
 641                                else
 642                                        chunksize = size;
 643
 644                                status = efi_file_read(files[j].handle,
 645                                                       &chunksize,
 646                                                       (void *)addr);
 647                                if (status != EFI_SUCCESS) {
 648                                        pr_efi_err(sys_table_arg, "Failed to read file\n");
 649                                        goto free_file_total;
 650                                }
 651                                addr += chunksize;
 652                                size -= chunksize;
 653                        }
 654
 655                        efi_file_close(files[j].handle);
 656                }
 657
 658        }
 659
 660        efi_call_early(free_pool, files);
 661
 662        *load_addr = file_addr;
 663        *load_size = file_size_total;
 664
 665        return status;
 666
 667free_file_total:
 668        efi_free(sys_table_arg, file_size_total, file_addr);
 669
 670close_handles:
 671        for (k = j; k < i; k++)
 672                efi_file_close(files[k].handle);
 673free_files:
 674        efi_call_early(free_pool, files);
 675fail:
 676        *load_addr = 0;
 677        *load_size = 0;
 678
 679        return status;
 680}
 681/*
 682 * Relocate a kernel image, either compressed or uncompressed.
 683 * In the ARM64 case, all kernel images are currently
 684 * uncompressed, and as such when we relocate it we need to
 685 * allocate additional space for the BSS segment. Any low
 686 * memory that this function should avoid needs to be
 687 * unavailable in the EFI memory map, as if the preferred
 688 * address is not available the lowest available address will
 689 * be used.
 690 */
 691efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
 692                                 unsigned long *image_addr,
 693                                 unsigned long image_size,
 694                                 unsigned long alloc_size,
 695                                 unsigned long preferred_addr,
 696                                 unsigned long alignment,
 697                                 unsigned long min_addr)
 698{
 699        unsigned long cur_image_addr;
 700        unsigned long new_addr = 0;
 701        efi_status_t status;
 702        unsigned long nr_pages;
 703        efi_physical_addr_t efi_addr = preferred_addr;
 704
 705        if (!image_addr || !image_size || !alloc_size)
 706                return EFI_INVALID_PARAMETER;
 707        if (alloc_size < image_size)
 708                return EFI_INVALID_PARAMETER;
 709
 710        cur_image_addr = *image_addr;
 711
 712        /*
 713         * The EFI firmware loader could have placed the kernel image
 714         * anywhere in memory, but the kernel has restrictions on the
 715         * max physical address it can run at.  Some architectures
 716         * also have a prefered address, so first try to relocate
 717         * to the preferred address.  If that fails, allocate as low
 718         * as possible while respecting the required alignment.
 719         */
 720        nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
 721        status = efi_call_early(allocate_pages,
 722                                EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 723                                nr_pages, &efi_addr);
 724        new_addr = efi_addr;
 725        /*
 726         * If preferred address allocation failed allocate as low as
 727         * possible.
 728         */
 729        if (status != EFI_SUCCESS) {
 730                status = efi_low_alloc_above(sys_table_arg, alloc_size,
 731                                             alignment, &new_addr, min_addr);
 732        }
 733        if (status != EFI_SUCCESS) {
 734                pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
 735                return status;
 736        }
 737
 738        /*
 739         * We know source/dest won't overlap since both memory ranges
 740         * have been allocated by UEFI, so we can safely use memcpy.
 741         */
 742        memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
 743
 744        /* Return the new address of the relocated image. */
 745        *image_addr = new_addr;
 746
 747        return status;
 748}
 749
 750/*
 751 * Get the number of UTF-8 bytes corresponding to an UTF-16 character.
 752 * This overestimates for surrogates, but that is okay.
 753 */
 754static int efi_utf8_bytes(u16 c)
 755{
 756        return 1 + (c >= 0x80) + (c >= 0x800);
 757}
 758
 759/*
 760 * Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
 761 */
 762static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
 763{
 764        unsigned int c;
 765
 766        while (n--) {
 767                c = *src++;
 768                if (n && c >= 0xd800 && c <= 0xdbff &&
 769                    *src >= 0xdc00 && *src <= 0xdfff) {
 770                        c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
 771                        src++;
 772                        n--;
 773                }
 774                if (c >= 0xd800 && c <= 0xdfff)
 775                        c = 0xfffd; /* Unmatched surrogate */
 776                if (c < 0x80) {
 777                        *dst++ = c;
 778                        continue;
 779                }
 780                if (c < 0x800) {
 781                        *dst++ = 0xc0 + (c >> 6);
 782                        goto t1;
 783                }
 784                if (c < 0x10000) {
 785                        *dst++ = 0xe0 + (c >> 12);
 786                        goto t2;
 787                }
 788                *dst++ = 0xf0 + (c >> 18);
 789                *dst++ = 0x80 + ((c >> 12) & 0x3f);
 790        t2:
 791                *dst++ = 0x80 + ((c >> 6) & 0x3f);
 792        t1:
 793                *dst++ = 0x80 + (c & 0x3f);
 794        }
 795
 796        return dst;
 797}
 798
 799#ifndef MAX_CMDLINE_ADDRESS
 800#define MAX_CMDLINE_ADDRESS     ULONG_MAX
 801#endif
 802
 803/*
 804 * Convert the unicode UEFI command line to ASCII to pass to kernel.
 805 * Size of memory allocated return in *cmd_line_len.
 806 * Returns NULL on error.
 807 */
 808char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
 809                          efi_loaded_image_t *image,
 810                          int *cmd_line_len)
 811{
 812        const u16 *s2;
 813        u8 *s1 = NULL;
 814        unsigned long cmdline_addr = 0;
 815        int load_options_chars = image->load_options_size / 2; /* UTF-16 */
 816        const u16 *options = image->load_options;
 817        int options_bytes = 0;  /* UTF-8 bytes */
 818        int options_chars = 0;  /* UTF-16 chars */
 819        efi_status_t status;
 820        u16 zero = 0;
 821
 822        if (options) {
 823                s2 = options;
 824                while (*s2 && *s2 != '\n'
 825                       && options_chars < load_options_chars) {
 826                        options_bytes += efi_utf8_bytes(*s2++);
 827                        options_chars++;
 828                }
 829        }
 830
 831        if (!options_chars) {
 832                /* No command line options, so return empty string*/
 833                options = &zero;
 834        }
 835
 836        options_bytes++;        /* NUL termination */
 837
 838        status = efi_high_alloc(sys_table_arg, options_bytes, 0,
 839                                &cmdline_addr, MAX_CMDLINE_ADDRESS);
 840        if (status != EFI_SUCCESS)
 841                return NULL;
 842
 843        s1 = (u8 *)cmdline_addr;
 844        s2 = (const u16 *)options;
 845
 846        s1 = efi_utf16_to_utf8(s1, s2, options_chars);
 847        *s1 = '\0';
 848
 849        *cmd_line_len = options_bytes;
 850        return (char *)cmdline_addr;
 851}
 852
 853/*
 854 * Handle calling ExitBootServices according to the requirements set out by the
 855 * spec.  Obtains the current memory map, and returns that info after calling
 856 * ExitBootServices.  The client must specify a function to perform any
 857 * processing of the memory map data prior to ExitBootServices.  A client
 858 * specific structure may be passed to the function via priv.  The client
 859 * function may be called multiple times.
 860 */
 861efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table_arg,
 862                                    void *handle,
 863                                    struct efi_boot_memmap *map,
 864                                    void *priv,
 865                                    efi_exit_boot_map_processing priv_func)
 866{
 867        efi_status_t status;
 868
 869        status = efi_get_memory_map(sys_table_arg, map);
 870
 871        if (status != EFI_SUCCESS)
 872                goto fail;
 873
 874        status = priv_func(sys_table_arg, map, priv);
 875        if (status != EFI_SUCCESS)
 876                goto free_map;
 877
 878        status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
 879
 880        if (status == EFI_INVALID_PARAMETER) {
 881                /*
 882                 * The memory map changed between efi_get_memory_map() and
 883                 * exit_boot_services().  Per the UEFI Spec v2.6, Section 6.4:
 884                 * EFI_BOOT_SERVICES.ExitBootServices we need to get the
 885                 * updated map, and try again.  The spec implies one retry
 886                 * should be sufficent, which is confirmed against the EDK2
 887                 * implementation.  Per the spec, we can only invoke
 888                 * get_memory_map() and exit_boot_services() - we cannot alloc
 889                 * so efi_get_memory_map() cannot be used, and we must reuse
 890                 * the buffer.  For all practical purposes, the headroom in the
 891                 * buffer should account for any changes in the map so the call
 892                 * to get_memory_map() is expected to succeed here.
 893                 */
 894                *map->map_size = *map->buff_size;
 895                status = efi_call_early(get_memory_map,
 896                                        map->map_size,
 897                                        *map->map,
 898                                        map->key_ptr,
 899                                        map->desc_size,
 900                                        map->desc_ver);
 901
 902                /* exit_boot_services() was called, thus cannot free */
 903                if (status != EFI_SUCCESS)
 904                        goto fail;
 905
 906                status = priv_func(sys_table_arg, map, priv);
 907                /* exit_boot_services() was called, thus cannot free */
 908                if (status != EFI_SUCCESS)
 909                        goto fail;
 910
 911                status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
 912        }
 913
 914        /* exit_boot_services() was called, thus cannot free */
 915        if (status != EFI_SUCCESS)
 916                goto fail;
 917
 918        return EFI_SUCCESS;
 919
 920free_map:
 921        efi_call_early(free_pool, *map->map);
 922fail:
 923        return status;
 924}
 925
 926#define GET_EFI_CONFIG_TABLE(bits)                                      \
 927static void *get_efi_config_table##bits(efi_system_table_t *_sys_table, \
 928                                        efi_guid_t guid)                \
 929{                                                                       \
 930        efi_system_table_##bits##_t *sys_table;                         \
 931        efi_config_table_##bits##_t *tables;                            \
 932        int i;                                                          \
 933                                                                        \
 934        sys_table = (typeof(sys_table))_sys_table;                      \
 935        tables = (typeof(tables))(unsigned long)sys_table->tables;      \
 936                                                                        \
 937        for (i = 0; i < sys_table->nr_tables; i++) {                    \
 938                if (efi_guidcmp(tables[i].guid, guid) != 0)             \
 939                        continue;                                       \
 940                                                                        \
 941                return (void *)(unsigned long)tables[i].table;          \
 942        }                                                               \
 943                                                                        \
 944        return NULL;                                                    \
 945}
 946GET_EFI_CONFIG_TABLE(32)
 947GET_EFI_CONFIG_TABLE(64)
 948
 949void *get_efi_config_table(efi_system_table_t *sys_table, efi_guid_t guid)
 950{
 951        if (efi_is_64bit())
 952                return get_efi_config_table64(sys_table, guid);
 953        else
 954                return get_efi_config_table32(sys_table, guid);
 955}
 956