src/boot/selfboot.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * Copyright (C) 2003 Eric W. Biederman <ebiederm@xmission.com>
   5  * Copyright (C) 2009 Ron Minnich <rminnich@gmail.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; version 2 of the License.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301 USA
  19  */
  20
  21 #include <arch/byteorder.h>
  22 #include <console/console.h>
  23 #include <fallback.h>
  24 #include <boot/elf.h>
  25 #include <boot/elf_boot.h>
  26 #include <boot/coreboot_tables.h>
  27 #include <stdint.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <cbfs.h>
  31 #include <lib.h>
  32
  33 /* Maximum physical address we can use for the coreboot bounce buffer. */
  34 #ifndef MAX_ADDR
  35 #define MAX_ADDR -1UL
  36 #endif
  37
  38 /* from coreboot_ram.ld: */
  39 extern unsigned char _ram_seg;
  40 extern unsigned char _eram_seg;
  41
  42 static const unsigned long lb_start = (unsigned long)&_ram_seg;
  43 static const unsigned long lb_end = (unsigned long)&_eram_seg;
  44
  45 struct segment {
  46         struct segment *next;
  47         struct segment *prev;
  48         unsigned long s_dstaddr;
  49         unsigned long s_srcaddr;
  50         unsigned long s_memsz;
  51         unsigned long s_filesz;
  52         int compression;
  53 };
  54
  55 /* The problem:
  56  * Static executables all want to share the same addresses
  57  * in memory because only a few addresses are reliably present on
  58  * a machine, and implementing general relocation is hard.
  59  *
  60  * The solution:
  61  * - Allocate a buffer the size of the coreboot image plus additional
  62  *   required space.
  63  * - Anything that would overwrite coreboot copy into the lower part of
  64  *   the buffer.
  65  * - After loading an ELF image copy coreboot to the top of the buffer.
  66  * - Then jump to the loaded image.
  67  *
  68  * Benefits:
  69  * - Nearly arbitrary standalone executables can be loaded.
  70  * - Coreboot is preserved, so it can be returned to.
  71  * - The implementation is still relatively simple,
  72  *   and much simpler than the general case implemented in kexec.
  73  */
  74
  75 static unsigned long bounce_size, bounce_buffer;
  76
  77 static void get_bounce_buffer(struct lb_memory *mem, unsigned long req_size)
  78 {
  79         unsigned long lb_size;
  80         unsigned long mem_entries;
  81         unsigned long buffer;
  82         int i;
  83         lb_size = lb_end - lb_start;
  84         /* Plus coreboot size so I have somewhere
  85          * to place a copy to return to.
  86          */
  87         lb_size = req_size + lb_size;
  88         mem_entries = (mem->size - sizeof(*mem)) / sizeof(mem->map[0]);
  89         buffer = 0;
  90         for(i = 0; i < mem_entries; i++) {
  91                 unsigned long mstart, mend;
  92                 unsigned long msize;
  93                 unsigned long tbuffer;
  94                 if (mem->map[i].type != LB_MEM_RAM)
  95                         continue;
  96                 if (unpack_lb64(mem->map[i].start) > MAX_ADDR)
  97                         continue;
  98                 if (unpack_lb64(mem->map[i].size) < lb_size)
  99                         continue;
 100                 mstart = unpack_lb64(mem->map[i].start);
 101                 msize = MAX_ADDR - mstart +1;
 102                 if (msize > unpack_lb64(mem->map[i].size))
 103                         msize = unpack_lb64(mem->map[i].size);
 104                 mend = mstart + msize;
 105                 tbuffer = mend - lb_size;
 106                 if (tbuffer < buffer)
 107                         continue;
 108                 buffer = tbuffer;
 109         }
 110         bounce_buffer = buffer;
 111         bounce_size = req_size;
 112 }
 113
 114 static int valid_area(struct lb_memory *mem, unsigned long buffer,
 115         unsigned long start, unsigned long len)
 116 {
 117         /* Check through all of the memory segments and ensure
 118          * the segment that was passed in is completely contained
 119          * in RAM.
 120          */
 121         int i;
 122         unsigned long end = start + len;
 123         unsigned long mem_entries = (mem->size - sizeof(*mem)) /
 124                 sizeof(mem->map[0]);
 125
 126         /* See if I conflict with the bounce buffer */
 127         if (end >= buffer) {
 128                 return 0;
 129         }
 130
 131         /* Walk through the table of valid memory ranges and see if I
 132          * have a match.
 133          */
 134         for(i = 0; i < mem_entries; i++) {
 135                 uint64_t mstart, mend;
 136                 uint32_t mtype;
 137                 mtype = mem->map[i].type;
 138                 mstart = unpack_lb64(mem->map[i].start);
 139                 mend = mstart + unpack_lb64(mem->map[i].size);
 140                 if ((mtype == LB_MEM_RAM) && (start >= mstart) && (end < mend)) {
 141                         break;
 142                 }
 143                 if ((mtype == LB_MEM_TABLE) && (start >= mstart) && (end < mend)) {
 144                         printk(BIOS_ERR, "Payload is overwriting coreboot tables.\n");
 145                         break;
 146                 }
 147         }
 148         if (i == mem_entries) {
 149                 if (start < (1024*1024) && end <=(1024*1024)) {
 150                         printk(BIOS_DEBUG, "Payload (probably SeaBIOS) loaded"
 151                                 " into a reserved area in the lower 1MB\n");
 152                         return 1;
 153                 }
 154                 printk(BIOS_ERR, "No matching ram area found for range:\n");
 155                 printk(BIOS_ERR, "  [0x%016lx, 0x%016lx)\n", start, end);
 156                 printk(BIOS_ERR, "Ram areas\n");
 157                 for(i = 0; i < mem_entries; i++) {
 158                         uint64_t mstart, mend;
 159                         uint32_t mtype;
 160                         mtype = mem->map[i].type;
 161                         mstart = unpack_lb64(mem->map[i].start);
 162                         mend = mstart + unpack_lb64(mem->map[i].size);
 163                         printk(BIOS_ERR, "  [0x%016lx, 0x%016lx) %s\n",
 164                                 (unsigned long)mstart,
 165                                 (unsigned long)mend,
 166                                 (mtype == LB_MEM_RAM)?"RAM":"Reserved");
 167
 168                 }
 169                 return 0;
 170         }
 171         return 1;
 172 }
 173
 174
 175 static int overlaps_coreboot(struct segment *seg)
 176 {
 177         unsigned long start, end;
 178         start = seg->s_dstaddr;
 179         end = start + seg->s_memsz;
 180         return !((end <= lb_start) || (start >= lb_end));
 181 }
 182
 183 static int relocate_segment(unsigned long buffer, struct segment *seg)
 184 {
 185         /* Modify all segments that want to load onto coreboot
 186          * to load onto the bounce buffer instead.
 187          */
 188         /* ret:  1 : A new segment is inserted before the seg.
 189          *       0 : A new segment is inserted after the seg, or no new one.
 190          */
 191         unsigned long start, middle, end, ret = 0;
 192
 193         printk(BIOS_SPEW, "lb: [0x%016lx, 0x%016lx)\n",
 194                 lb_start, lb_end);
 195
 196         /* I don't conflict with coreboot so get out of here */
 197         if (!overlaps_coreboot(seg))
 198                 return 0;
 199
 200         start = seg->s_dstaddr;
 201         middle = start + seg->s_filesz;
 202         end = start + seg->s_memsz;
 203
 204         printk(BIOS_SPEW, "segment: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 205                 start, middle, end);
 206
 207         if (seg->compression == CBFS_COMPRESS_NONE) {
 208                 /* Slice off a piece at the beginning
 209                  * that doesn't conflict with coreboot.
 210                  */
 211                 if (start < lb_start) {
 212                         struct segment *new;
 213                         unsigned long len = lb_start - start;
 214                         new = malloc(sizeof(*new));
 215                         *new = *seg;
 216                         new->s_memsz = len;
 217                         seg->s_memsz -= len;
 218                         seg->s_dstaddr += len;
 219                         seg->s_srcaddr += len;
 220                         if (seg->s_filesz > len) {
 221                                 new->s_filesz = len;
 222                                 seg->s_filesz -= len;
 223                         } else {
 224                                 seg->s_filesz = 0;
 225                         }
 226
 227                         /* Order by stream offset */
 228                         new->next = seg;
 229                         new->prev = seg->prev;
 230                         seg->prev->next = new;
 231                         seg->prev = new;
 232
 233                         /* compute the new value of start */
 234                         start = seg->s_dstaddr;
 235
 236                         printk(BIOS_SPEW, "   early: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 237                                 new->s_dstaddr,
 238                                 new->s_dstaddr + new->s_filesz,
 239                                 new->s_dstaddr + new->s_memsz);
 240
 241                         ret = 1;
 242                 }
 243
 244                 /* Slice off a piece at the end
 245                  * that doesn't conflict with coreboot
 246                  */
 247                 if (end > lb_end) {
 248                         unsigned long len = lb_end - start;
 249                         struct segment *new;
 250                         new = malloc(sizeof(*new));
 251                         *new = *seg;
 252                         seg->s_memsz = len;
 253                         new->s_memsz -= len;
 254                         new->s_dstaddr += len;
 255                         new->s_srcaddr += len;
 256                         if (seg->s_filesz > len) {
 257                                 seg->s_filesz = len;
 258                                 new->s_filesz -= len;
 259                         } else {
 260                                 new->s_filesz = 0;
 261                         }
 262                         /* Order by stream offset */
 263                         new->next = seg->next;
 264                         new->prev = seg;
 265                         seg->next->prev = new;
 266                         seg->next = new;
 267
 268                         printk(BIOS_SPEW, "   late: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 269                                 new->s_dstaddr,
 270                                 new->s_dstaddr + new->s_filesz,
 271                                 new->s_dstaddr + new->s_memsz);
 272                 }
 273         }
 274
 275         /* Now retarget this segment onto the bounce buffer */
 276         /* sort of explanation: the buffer is a 1:1 mapping to coreboot.
 277          * so you will make the dstaddr be this buffer, and it will get copied
 278          * later to where coreboot lives.
 279          */
 280         seg->s_dstaddr = buffer + (seg->s_dstaddr - lb_start);
 281
 282         printk(BIOS_SPEW, " bounce: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 283                 seg->s_dstaddr,
 284                 seg->s_dstaddr + seg->s_filesz,
 285                 seg->s_dstaddr + seg->s_memsz);
 286
 287         return ret;
 288 }
 289
 290
 291 static int build_self_segment_list(
 292         struct segment *head,
 293         struct lb_memory *mem,
 294         struct cbfs_payload *payload, u32 *entry)
 295 {
 296         struct segment *new;
 297         struct segment *ptr;
 298         struct cbfs_payload_segment *segment, *first_segment;
 299         memset(head, 0, sizeof(*head));
 300         head->next = head->prev = head;
 301         first_segment = segment = &payload->segments;
 302
 303         while(1) {
 304                 printk(BIOS_DEBUG, "Loading segment from rom address 0x%p\n", segment);
 305                 switch(segment->type) {
 306                 case PAYLOAD_SEGMENT_PARAMS:
 307                         printk(BIOS_DEBUG, "  parameter section (skipped)\n");
 308                         segment++;
 309                         continue;
 310
 311                 case PAYLOAD_SEGMENT_CODE:
 312                 case PAYLOAD_SEGMENT_DATA:
 313                         printk(BIOS_DEBUG, "  %s (compression=%x)\n",
 314                                         segment->type == PAYLOAD_SEGMENT_CODE ?  "code" : "data",
 315                                         ntohl(segment->compression));
 316                         new = malloc(sizeof(*new));
 317                         new->s_dstaddr = ntohll(segment->load_addr);
 318                         new->s_memsz = ntohl(segment->mem_len);
 319                         new->compression = ntohl(segment->compression);
 320
 321                         new->s_srcaddr = (u32) ((unsigned char *)first_segment)
 322                                                 + ntohl(segment->offset);
 323                         new->s_filesz = ntohl(segment->len);
 324                         printk(BIOS_DEBUG, "  New segment dstaddr 0x%lx memsize 0x%lx srcaddr 0x%lx filesize 0x%lx\n",
 325                                 new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
 326                         /* Clean up the values */
 327                         if (new->s_filesz > new->s_memsz)  {
 328                                 new->s_filesz = new->s_memsz;
 329                         }
 330                         printk(BIOS_DEBUG, "  (cleaned up) New segment addr 0x%lx size 0x%lx offset 0x%lx filesize 0x%lx\n",
 331                                 new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
 332                         break;
 333
 334                 case PAYLOAD_SEGMENT_BSS:
 335                         printk(BIOS_DEBUG, "  BSS 0x%p (%d byte)\n", (void *)
 336                                         (intptr_t)ntohll(segment->load_addr),
 337                                         ntohl(segment->mem_len));
 338                         new = malloc(sizeof(*new));
 339                         new->s_filesz = 0;
 340                         new->s_dstaddr = ntohll(segment->load_addr);
 341                         new->s_memsz = ntohl(segment->mem_len);
 342                         break;
 343
 344                 case PAYLOAD_SEGMENT_ENTRY:
 345                         printk(BIOS_DEBUG, "  Entry Point 0x%p\n", (void *) ntohl((u32) segment->load_addr));
 346                         *entry =  ntohll(segment->load_addr);
 347                         /* Per definition, a payload always has the entry point
 348                          * as last segment. Thus, we use the occurence of the
 349                          * entry point as break condition for the loop.
 350                          * Can we actually just look at the number of section?
 351                          */
 352                         return 1;
 353
 354                 default:
 355                         /* We found something that we don't know about. Throw
 356                          * hands into the sky and run away!
 357                          */
 358                         printk(BIOS_EMERG, "Bad segment type %x\n", segment->type);
 359                         return -1;
 360                 }
 361
 362                 /* We have found another CODE, DATA or BSS segment */
 363                 segment++;
 364
 365                 /* Find place where to insert our segment */
 366                 for(ptr = head->next; ptr != head; ptr = ptr->next) {
 367                         if (new->s_srcaddr < ntohll(segment->load_addr))
 368                                 break;
 369                 }
 370
 371                 /* Order by stream offset */
 372                 new->next = ptr;
 373                 new->prev = ptr->prev;
 374                 ptr->prev->next = new;
 375                 ptr->prev = new;
 376         }
 377
 378         return 1;
 379 }
 380
 381 static int load_self_segments(
 382         struct segment *head,
 383         struct lb_memory *mem,
 384         struct cbfs_payload *payload)
 385 {
 386         struct segment *ptr;
 387
 388         unsigned long bounce_high = lb_end;
 389         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 390                 if (!overlaps_coreboot(ptr))
 391                         continue;
 392                 if (ptr->s_dstaddr + ptr->s_memsz > bounce_high)
 393                         bounce_high = ptr->s_dstaddr + ptr->s_memsz;
 394         }
 395         get_bounce_buffer(mem, bounce_high - lb_start);
 396         if (!bounce_buffer) {
 397                 printk(BIOS_ERR, "Could not find a bounce buffer...\n");
 398                 return 0;
 399         }
 400         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 401                 /* Verify the memory addresses in the segment are valid */
 402                 if (!valid_area(mem, bounce_buffer, ptr->s_dstaddr, ptr->s_memsz))
 403                         return 0;
 404         }
 405         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 406                 unsigned char *dest, *src;
 407                 printk(BIOS_DEBUG, "Loading Segment: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
 408                         ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);
 409
 410                 /* Modify the segment to load onto the bounce_buffer if necessary.
 411                  */
 412                 if (relocate_segment(bounce_buffer, ptr)) {
 413                         ptr = (ptr->prev)->prev;
 414                         continue;
 415                 }
 416
 417                 printk(BIOS_DEBUG, "Post relocation: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
 418                         ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);
 419
 420                 /* Compute the boundaries of the segment */
 421                 dest = (unsigned char *)(ptr->s_dstaddr);
 422                 src = (unsigned char *)(ptr->s_srcaddr);
 423
 424                 /* Copy data from the initial buffer */
 425                 if (ptr->s_filesz) {
 426                         unsigned char *middle, *end;
 427                         size_t len;
 428                         len = ptr->s_filesz;
 429                         switch(ptr->compression) {
 430                                 case CBFS_COMPRESS_LZMA: {
 431                                         printk(BIOS_DEBUG, "using LZMA\n");
 432                                         len = ulzma(src, dest);
 433                                         if (!len) /* Decompression Error. */
 434                                                 return 0;
 435                                         break;
 436                                 }
 437 #if CONFIG_COMPRESSED_PAYLOAD_NRV2B
 438                                 case CBFS_COMPRESS_NRV2B: {
 439                                         printk(BIOS_DEBUG, "using NRV2B\n");
 440                                         unsigned long unrv2b(u8 *src, u8 *dst, unsigned long *ilen_p);
 441                                         unsigned long tmp;
 442                                         len = unrv2b(src, dest, &tmp);
 443                                         break;
 444                                 }
 445 #endif
 446                                 case CBFS_COMPRESS_NONE: {
 447                                         printk(BIOS_DEBUG, "it's not compressed!\n");
 448                                         memcpy(dest, src, len);
 449                                         break;
 450                                 }
 451                                 default:
 452                                         printk(BIOS_INFO,  "CBFS:  Unknown compression type %d\n", ptr->compression);
 453                                         return -1;
 454                         }
 455                         end = dest + ptr->s_memsz;
 456                         middle = dest + len;
 457                         printk(BIOS_SPEW, "[ 0x%08lx, %08lx, 0x%08lx) <- %08lx\n",
 458                                 (unsigned long)dest,
 459                                 (unsigned long)middle,
 460                                 (unsigned long)end,
 461                                 (unsigned long)src);
 462
 463                         /* Zero the extra bytes between middle & end */
 464                         if (middle < end) {
 465                                 printk(BIOS_DEBUG, "Clearing Segment: addr: 0x%016lx memsz: 0x%016lx\n",
 466                                         (unsigned long)middle, (unsigned long)(end - middle));
 467
 468                                 /* Zero the extra bytes */
 469                                 memset(middle, 0, end - middle);
 470                         }
 471                         /* Copy the data that's outside the area that shadows coreboot_ram */
 472                         printk(BIOS_DEBUG, "dest %p, end %p, bouncebuffer %lx\n", dest, end, bounce_buffer);
 473                         if ((unsigned long)end > bounce_buffer) {
 474                                 if ((unsigned long)dest < bounce_buffer) {
 475                                         unsigned char *from = dest;
 476                                         unsigned char *to = (unsigned char*)(lb_start-(bounce_buffer-(unsigned long)dest));
 477                                         unsigned long amount = bounce_buffer-(unsigned long)dest;
 478                                         printk(BIOS_DEBUG, "move prefix around: from %p, to %p, amount: %lx\n", from, to, amount);
 479                                         memcpy(to, from, amount);
 480                                 }
 481                                 if ((unsigned long)end > bounce_buffer + (lb_end - lb_start)) {
 482                                         unsigned long from = bounce_buffer + (lb_end - lb_start);
 483                                         unsigned long to = lb_end;
 484                                         unsigned long amount = (unsigned long)end - from;
 485                                         printk(BIOS_DEBUG, "move suffix around: from %lx, to %lx, amount: %lx\n", from, to, amount);
 486                                         memcpy((char*)to, (char*)from, amount);
 487                                 }
 488                         }
 489                 }
 490         }
 491         return 1;
 492 }
 493
 494 static int selfboot(struct lb_memory *mem, struct cbfs_payload *payload)
 495 {
 496         u32 entry=0;
 497         struct segment head;
 498
 499         /* Preprocess the self segments */
 500         if (!build_self_segment_list(&head, mem, payload, &entry))
 501                 goto out;
 502
 503         /* Load the segments */
 504         if (!load_self_segments(&head, mem, payload))
 505                 goto out;
 506
 507         printk(BIOS_SPEW, "Loaded segments\n");
 508
 509         /* Reset to booting from this image as late as possible */
 510         boot_successful();
 511
 512         printk(BIOS_DEBUG, "Jumping to boot code at %x\n", entry);
 513         post_code(POST_ENTER_ELF_BOOT);
 514
 515         /* Jump to kernel */
 516         jmp_to_elf_entry((void*)entry, bounce_buffer, bounce_size);
 517         return 1;
 518
 519 out:
 520         return 0;
 521 }
 522
 523 void *cbfs_load_payload(struct lb_memory *lb_mem, const char *name)
 524 {
 525         struct cbfs_payload *payload;
 526
 527         payload = (struct cbfs_payload *)cbfs_find_file(name, CBFS_TYPE_PAYLOAD);
 528         if (payload == NULL)
 529                 return (void *) -1;
 530         printk(BIOS_DEBUG, "Got a payload\n");
 531
 532         selfboot(lb_mem, payload);
 533         printk(BIOS_EMERG, "SELFBOOT RETURNED!\n");
 534
 535         return (void *) -1;
 536 }
 537