boot/bootmeth_cros.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Bootmethod for ChromiumOS
   4  *
   5  * Copyright 2023 Google LLC
   6  * Written by Simon Glass <sjg@chromium.org>
   7  */
   8
   9 #define LOG_CATEGORY UCLASS_BOOTSTD
  10
  11 #include <common.h>
  12 #include <blk.h>
  13 #include <bootdev.h>
  14 #include <bootflow.h>
  15 #include <bootm.h>
  16 #include <bootmeth.h>
  17 #include <display_options.h>
  18 #include <dm.h>
  19 #include <efi.h>
  20 #include <malloc.h>
  21 #include <mapmem.h>
  22 #include <part.h>
  23 #include <linux/sizes.h>
  24 #include "bootmeth_cros.h"
  25
  26 static const efi_guid_t cros_kern_type = PARTITION_CROS_KERNEL;
  27
  28 /*
  29  * Layout of the ChromeOS kernel
  30  *
  31  * Partitions 2 and 4 contain kernels with type GUID_CROS_KERNEL
  32  *
  33  * Contents are:
  34  *
  35  * Offset       Contents
  36  *   0          struct vb2_keyblock
  37  *   m          struct vb2_kernel_preamble
  38  *   m + n      kernel buffer
  39  *
  40  * m is keyblock->keyblock_size
  41  * n is preamble->preamble_size
  42  *
  43  * The kernel buffer itself consists of various parts:
  44  *
  45  * Offset       Contents
  46  *   m + n      kernel image (Flat vmlinux binary or FIT)
  47  *   b - 8KB    Command line text
  48  *   b - 4KB    X86 setup block (struct boot_params, extends for about 16KB)
  49  *   b          X86 bootloader (continuation of setup block)
  50  *   b + 16KB   X86 setup block (copy, used for hold data pointed to)
  51  *
  52  * b is m + n + preamble->bootloader_address - preamble->body_load_address
  53  *
  54  * Useful metadata extends from b - 8KB through to b + 32 KB
  55  */
  56
  57 enum {
  58         PROBE_SIZE      = SZ_4K,        /* initial bytes read from partition */
  59
  60         X86_SETUP_OFFSET = -0x1000,     /* setup offset relative to base */
  61         CMDLINE_OFFSET  = -0x2000,      /* cmdline offset relative to base */
  62         X86_KERNEL_OFFSET = 0x4000,     /* kernel offset relative to base */
  63 };
  64
  65 /**
  66  * struct cros_priv - Private data
  67  *
  68  * This is read from the disk and recorded for use when the full kernel must
  69  * be loaded and booted
  70  *
  71  * @body_offset: Offset of kernel body from start of partition (in bytes)
  72  * @body_size: Size of kernel body in bytes
  73  * @part_start: Block offset of selected partition from the start of the disk
  74  * @body_load_address: Nominal load address for kernel body
  75  * @bootloader_address: Address of bootloader, after body is loaded at
  76  *      body_load_address
  77  * @bootloader_size:  Size of bootloader in bytes
  78  * @info_buf: Buffer containing ChromiumOS info
  79  */
  80 struct cros_priv {
  81         ulong body_offset;
  82         ulong body_size;
  83         lbaint_t part_start;
  84         ulong body_load_address;
  85         ulong bootloader_address;
  86         ulong bootloader_size;
  87         void *info_buf;
  88 };
  89
  90 static int cros_check(struct udevice *dev, struct bootflow_iter *iter)
  91 {
  92         /* This only works on block and network devices */
  93         if (bootflow_iter_check_blk(iter))
  94                 return log_msg_ret("blk", -ENOTSUPP);
  95
  96         return 0;
  97 }
  98
  99 static int copy_cmdline(const char *from, const char *uuid, char **bufp)
 100 {
 101         const int maxlen = 2048;
 102         char buf[maxlen];
 103         char *cmd, *to, *end;
 104         int len;
 105
 106         /* Allow space for cmdline + UUID */
 107         len = strnlen(from, sizeof(buf));
 108         if (len >= maxlen)
 109                 return -E2BIG;
 110
 111         log_debug("uuid %d %s\n", uuid ? (int)strlen(uuid) : 0, uuid);
 112         for (to = buf, end = buf + maxlen - UUID_STR_LEN - 1; *from; from++) {
 113                 if (to >= end)
 114                         return -E2BIG;
 115                 if (from[0] == '%' && from[1] == 'U' && uuid &&
 116                     strlen(uuid) == UUID_STR_LEN) {
 117                         strcpy(to, uuid);
 118                         to += UUID_STR_LEN;
 119                         from++;
 120                 } else {
 121                         *to++ = *from;
 122                 }
 123         }
 124         *to = '\0';
 125         len = to - buf;
 126         cmd = strdup(buf);
 127         if (!cmd)
 128                 return -ENOMEM;
 129         free(*bufp);
 130         *bufp = cmd;
 131
 132         return 0;
 133 }
 134
 135 /**
 136  * scan_part() - Scan a kernel partition to see if has a ChromeOS header
 137  *
 138  * This reads the first PROBE_SIZE of a partition, loookng for
 139  * VB2_KEYBLOCK_MAGIC
 140  *
 141  * @blk: Block device to scan
 142  * @partnum: Partition number to scan
 143  * @info: Please to put partition info
 144  * @hdrp: Return allocated keyblock header on success
 145  */
 146 static int scan_part(struct udevice *blk, int partnum,
 147                      struct disk_partition *info, struct vb2_keyblock **hdrp)
 148 {
 149         struct blk_desc *desc = dev_get_uclass_plat(blk);
 150         struct vb2_keyblock *hdr;
 151         struct uuid type;
 152         ulong num_blks;
 153         int ret;
 154
 155         if (!partnum)
 156                 return log_msg_ret("efi", -ENOENT);
 157
 158         ret = part_get_info(desc, partnum, info);
 159         if (ret)
 160                 return log_msg_ret("part", ret);
 161
 162         /* Check for kernel partition type */
 163         log_debug("part %x: type=%s\n", partnum, info->type_guid);
 164         if (uuid_str_to_bin(info->type_guid, (u8 *)&type, UUID_STR_FORMAT_GUID))
 165                 return log_msg_ret("typ", -EINVAL);
 166
 167         if (memcmp(&cros_kern_type, &type, sizeof(type)))
 168                 return log_msg_ret("typ", -ENOEXEC);
 169
 170         /* Make a buffer for the header information */
 171         num_blks = PROBE_SIZE >> desc->log2blksz;
 172         log_debug("Reading header, blk=%s, start=%lx, blocks=%lx\n",
 173                   blk->name, (ulong)info->start, num_blks);
 174         hdr = memalign(SZ_1K, PROBE_SIZE);
 175         if (!hdr)
 176                 return log_msg_ret("hdr", -ENOMEM);
 177         ret = blk_read(blk, info->start, num_blks, hdr);
 178         if (ret != num_blks) {
 179                 free(hdr);
 180                 return log_msg_ret("inf", -EIO);
 181         }
 182
 183         if (memcmp(VB2_KEYBLOCK_MAGIC, hdr->magic, VB2_KEYBLOCK_MAGIC_SIZE)) {
 184                 free(hdr);
 185                 log_debug("no magic\n");
 186                 return -ENOENT;
 187         }
 188
 189         *hdrp = hdr;
 190
 191         return 0;
 192 }
 193
 194 /**
 195  * cros_read_buf() - Read information into a buf and parse it
 196  *
 197  * @bflow: Bootflow to update
 198  * @buf: Buffer to use
 199  * @size: Size of buffer and number of bytes to read thereinto
 200  * @start: Start offset to read from on disk
 201  * @before_base: Number of bytes to read before the bootloader base
 202  * @uuid: UUID string if supported, else NULL
 203  * Return: 0 if OK, -ENOMEM if out of memory, -EIO on read failure
 204  */
 205 static int cros_read_buf(struct bootflow *bflow, void *buf, ulong size,
 206                          loff_t start, ulong before_base, const char *uuid)
 207 {
 208         struct blk_desc *desc = dev_get_uclass_plat(bflow->blk);
 209         ulong base, setup, cmdline, kern_base;
 210         ulong num_blks;
 211         int ret;
 212
 213         num_blks = size >> desc->log2blksz;
 214         log_debug("Reading info to %lx, blk=%s, size=%lx, blocks=%lx\n",
 215                   (ulong)map_to_sysmem(buf), bflow->blk->name, size, num_blks);
 216         ret = blk_read(bflow->blk, start, num_blks, buf);
 217         if (ret != num_blks)
 218                 return log_msg_ret("inf", -EIO);
 219         base = map_to_sysmem(buf) + before_base;
 220
 221         setup = base + X86_SETUP_OFFSET;
 222         cmdline = base + CMDLINE_OFFSET;
 223         kern_base = base + X86_KERNEL_OFFSET;
 224         log_debug("base %lx setup %lx cmdline %lx kern_base %lx\n", base,
 225                   setup, cmdline, kern_base);
 226
 227 #ifdef CONFIG_X86
 228         const char *version;
 229
 230         version = zimage_get_kernel_version(map_sysmem(setup, 0),
 231                                             map_sysmem(kern_base, 0));
 232         log_debug("version %s\n", version);
 233         if (version)
 234                 bflow->name = strdup(version);
 235 #endif
 236         if (!bflow->name)
 237                 bflow->name = strdup("ChromeOS");
 238         if (!bflow->name)
 239                 return log_msg_ret("nam", -ENOMEM);
 240         bflow->os_name = strdup("ChromeOS");
 241         if (!bflow->os_name)
 242                 return log_msg_ret("os", -ENOMEM);
 243
 244         ret = copy_cmdline(map_sysmem(cmdline, 0), uuid, &bflow->cmdline);
 245         if (ret)
 246                 return log_msg_ret("cmd", ret);
 247         bflow->x86_setup = map_sysmem(setup, 0);
 248
 249         return 0;
 250 }
 251
 252 /**
 253  * cros_read_info() - Read information and fill out the bootflow
 254  *
 255  * @bflow: Bootflow to update
 256  * @uuid: UUID string if supported, else NULL
 257  * @preamble: Kernel preamble information
 258  * Return: 0 if OK, -ENOMEM if out of memory, -EIO on read failure
 259  */
 260 static int cros_read_info(struct bootflow *bflow, const char *uuid,
 261                           const struct vb2_kernel_preamble *preamble)
 262 {
 263         struct cros_priv *priv = bflow->bootmeth_priv;
 264         struct udevice *blk = bflow->blk;
 265         struct blk_desc *desc = dev_get_uclass_plat(blk);
 266         ulong offset, size, before_base;
 267         void *buf;
 268         int ret;
 269
 270         log_debug("Kernel preamble at %lx, version major %x, minor %x\n",
 271                   (ulong)map_to_sysmem(preamble),
 272                   preamble->header_version_major,
 273                   preamble->header_version_minor);
 274
 275         log_debug("  - load_address %lx, bl_addr %lx, bl_size %lx\n",
 276                   (ulong)preamble->body_load_address,
 277                   (ulong)preamble->bootloader_address,
 278                   (ulong)preamble->bootloader_size);
 279
 280         priv->body_size = preamble->body_signature.data_size;
 281         priv->body_load_address = preamble->body_load_address;
 282         priv->bootloader_address = preamble->bootloader_address;
 283         priv->bootloader_size = preamble->bootloader_size;
 284         log_debug("Kernel body at %lx size %lx\n", priv->body_offset,
 285                   priv->body_size);
 286
 287         /* Work out how many bytes to read before the bootloader base */
 288         before_base = -CMDLINE_OFFSET;
 289
 290         /* Read the cmdline through to the end of the bootloader */
 291         size = priv->bootloader_size + before_base;
 292         offset = priv->body_offset +
 293                 (priv->bootloader_address - priv->body_load_address) +
 294                 CMDLINE_OFFSET;
 295         buf = malloc(size);
 296         if (!buf)
 297                 return log_msg_ret("buf", -ENOMEM);
 298
 299         ret = cros_read_buf(bflow, buf, size,
 300                             priv->part_start + (offset >> desc->log2blksz),
 301                             before_base, uuid);
 302         if (ret) {
 303                 /* Clear this since the buffer is invalid */
 304                 bflow->x86_setup = NULL;
 305                 free(buf);
 306                 return log_msg_ret("pro", ret);
 307         }
 308         priv->info_buf = buf;
 309
 310         return 0;
 311 }
 312
 313 static int cros_read_kernel(struct bootflow *bflow)
 314 {
 315         struct blk_desc *desc = dev_get_uclass_plat(bflow->blk);
 316         struct cros_priv *priv = bflow->bootmeth_priv;
 317         ulong base, setup;
 318         ulong num_blks;
 319         void *buf;
 320         int ret;
 321
 322         bflow->size = priv->body_size;
 323
 324         buf = memalign(SZ_1K, priv->body_size);
 325         if (!buf)
 326                 return log_msg_ret("buf", -ENOMEM);
 327
 328         /* Check that the header is not smaller than permitted */
 329         if (priv->body_offset < PROBE_SIZE)
 330                 return log_msg_ret("san", EFAULT);
 331
 332         /* Read kernel body */
 333         num_blks = priv->body_size >> desc->log2blksz;
 334         log_debug("Reading body to %lx, blk=%s, size=%lx, blocks=%lx\n",
 335                   (ulong)map_to_sysmem(buf), bflow->blk->name, priv->body_size,
 336                   num_blks);
 337         ret = blk_read(bflow->blk,
 338                        priv->part_start + (priv->body_offset >> desc->log2blksz),
 339                        num_blks, buf);
 340         if (ret != num_blks)
 341                 return log_msg_ret("inf", -EIO);
 342         base = map_to_sysmem(buf) + priv->bootloader_address -
 343                 priv->body_load_address;
 344         setup = base + X86_SETUP_OFFSET;
 345
 346         bflow->buf = buf;
 347         bflow->x86_setup = map_sysmem(setup, 0);
 348
 349         return 0;
 350 }
 351
 352 static int cros_read_bootflow(struct udevice *dev, struct bootflow *bflow)
 353 {
 354         const struct vb2_kernel_preamble *preamble;
 355         struct disk_partition info;
 356         struct vb2_keyblock *hdr;
 357         const char *uuid = NULL;
 358         struct cros_priv *priv;
 359         int ret;
 360
 361         log_debug("starting, part=%x\n", bflow->part);
 362
 363         /* Check for kernel partitions */
 364         ret = scan_part(bflow->blk, bflow->part, &info, &hdr);
 365         if (ret) {
 366                 log_debug("- scan failed: err=%d\n", ret);
 367                 return log_msg_ret("scan", ret);
 368         }
 369
 370         priv = malloc(sizeof(struct cros_priv));
 371         if (!priv) {
 372                 free(hdr);
 373                 return log_msg_ret("buf", -ENOMEM);
 374         }
 375         bflow->bootmeth_priv = priv;
 376
 377         log_debug("Selected partition %d, header at %lx\n", bflow->part,
 378                   (ulong)map_to_sysmem(hdr));
 379
 380         /* Grab a few things from the preamble */
 381         preamble = (void *)hdr + hdr->keyblock_size;
 382         priv->body_offset = hdr->keyblock_size + preamble->preamble_size;
 383         priv->part_start = info.start;
 384
 385         /* Now read everything we can learn about kernel */
 386 #if CONFIG_IS_ENABLED(PARTITION_UUIDS)
 387         uuid = info.uuid;
 388 #endif
 389         ret = cros_read_info(bflow, uuid, preamble);
 390         preamble = NULL;
 391         free(hdr);
 392         if (ret) {
 393                 free(priv->info_buf);
 394                 free(priv);
 395                 return log_msg_ret("inf", ret);
 396         }
 397         bflow->size = priv->body_size;
 398         bflow->state = BOOTFLOWST_READY;
 399
 400         return 0;
 401 }
 402
 403 static int cros_read_file(struct udevice *dev, struct bootflow *bflow,
 404                          const char *file_path, ulong addr, ulong *sizep)
 405 {
 406         return -ENOSYS;
 407 }
 408
 409 #if CONFIG_IS_ENABLED(BOOTSTD_FULL)
 410 static int cros_read_all(struct udevice *dev, struct bootflow *bflow)
 411 {
 412         int ret;
 413
 414         if (bflow->buf)
 415                 return log_msg_ret("ld", -EALREADY);
 416         ret = cros_read_kernel(bflow);
 417         if (ret)
 418                 return log_msg_ret("rd", ret);
 419
 420         return 0;
 421 }
 422 #endif /* BOOTSTD_FULL */
 423
 424 static int cros_boot(struct udevice *dev, struct bootflow *bflow)
 425 {
 426         int ret;
 427
 428         if (!bflow->buf) {
 429                 ret = cros_read_kernel(bflow);
 430                 if (ret)
 431                         return log_msg_ret("rd", ret);
 432         }
 433
 434         if (IS_ENABLED(CONFIG_X86)) {
 435                 ret = zboot_start(map_to_sysmem(bflow->buf), bflow->size, 0, 0,
 436                                   map_to_sysmem(bflow->x86_setup),
 437                                   bflow->cmdline);
 438         } else {
 439                 ret = bootm_boot_start(map_to_sysmem(bflow->buf),
 440                                        bflow->cmdline);
 441         }
 442
 443         return log_msg_ret("go", ret);
 444 }
 445
 446 static int cros_bootmeth_bind(struct udevice *dev)
 447 {
 448         struct bootmeth_uc_plat *plat = dev_get_uclass_plat(dev);
 449
 450         plat->desc = "ChromiumOS boot";
 451         plat->flags = BOOTMETHF_ANY_PART;
 452
 453         return 0;
 454 }
 455
 456 static struct bootmeth_ops cros_bootmeth_ops = {
 457         .check          = cros_check,
 458         .read_bootflow  = cros_read_bootflow,
 459         .read_file      = cros_read_file,
 460         .boot           = cros_boot,
 461 #if CONFIG_IS_ENABLED(BOOTSTD_FULL)
 462         .read_all       = cros_read_all,
 463 #endif /* BOOTSTD_FULL */
 464 };
 465
 466 static const struct udevice_id cros_bootmeth_ids[] = {
 467         { .compatible = "u-boot,cros" },
 468         { }
 469 };
 470
 471 U_BOOT_DRIVER(bootmeth_cros) = {
 472         .name           = "bootmeth_cros",
 473         .id             = UCLASS_BOOTMETH,
 474         .of_match       = cros_bootmeth_ids,
 475         .ops            = &cros_bootmeth_ops,
 476         .bind           = cros_bootmeth_bind,
 477 };