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 <ip_checksum.h>
  28 #include <stdint.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <cbfs.h>
  32 #include <lib.h>
  33
  34 /* Maximum physical address we can use for the coreboot bounce buffer.
  35  */
  36 #ifndef MAX_ADDR
  37 #define MAX_ADDR -1UL
  38 #endif
  39
  40 extern unsigned char _ram_seg;
  41 extern unsigned char _eram_seg;
  42
  43 struct segment {
  44         struct segment *next;
  45         struct segment *prev;
  46         struct segment *phdr_next;
  47         struct segment *phdr_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 struct verify_callback {
  56         struct verify_callback *next;
  57         int (*callback)(struct verify_callback *vcb,
  58                 Elf_ehdr *ehdr, Elf_phdr *phdr, struct segment *head);
  59         unsigned long desc_offset;
  60         unsigned long desc_addr;
  61 };
  62
  63 struct ip_checksum_vcb {
  64         struct verify_callback data;
  65         unsigned short ip_checksum;
  66 };
  67
  68 static int selfboot(struct lb_memory *mem, struct cbfs_payload *payload);
  69
  70 void * cbfs_load_payload(struct lb_memory *lb_mem, const char *name)
  71 {
  72         struct cbfs_payload *payload;
  73
  74         payload = (struct cbfs_payload *)cbfs_find_file(name, CBFS_TYPE_PAYLOAD);
  75         if (payload == NULL)
  76                 return (void *) -1;
  77         printk(BIOS_DEBUG, "Got a payload\n");
  78
  79         selfboot(lb_mem, payload);
  80         printk(BIOS_EMERG, "SELFBOOT RETURNED!\n");
  81
  82         return (void *) -1;
  83 }
  84
  85 /* The problem:
  86  * Static executables all want to share the same addresses
  87  * in memory because only a few addresses are reliably present on
  88  * a machine, and implementing general relocation is hard.
  89  *
  90  * The solution:
  91  * - Allocate a buffer the size of the coreboot image plus additional
  92  *   required space.
  93  * - Anything that would overwrite coreboot copy into the lower part of
  94  *   the buffer.
  95  * - After loading an ELF image copy coreboot to the top of the buffer.
  96  * - Then jump to the loaded image.
  97  *
  98  * Benefits:
  99  * - Nearly arbitrary standalone executables can be loaded.
 100  * - Coreboot is preserved, so it can be returned to.
 101  * - The implementation is still relatively simple,
 102  *   and much simpler than the general case implemented in kexec.
 103  *
 104  */
 105
 106 static unsigned long bounce_size, bounce_buffer;
 107
 108 static void get_bounce_buffer(struct lb_memory *mem, unsigned long req_size)
 109 {
 110         unsigned long lb_size;
 111         unsigned long mem_entries;
 112         unsigned long buffer;
 113         int i;
 114         lb_size = (unsigned long)(&_eram_seg - &_ram_seg);
 115         /* Double coreboot size so I have somewhere to place a copy to return to */
 116         lb_size = req_size + lb_size;
 117         mem_entries = (mem->size - sizeof(*mem))/sizeof(mem->map[0]);
 118         buffer = 0;
 119         for(i = 0; i < mem_entries; i++) {
 120                 unsigned long mstart, mend;
 121                 unsigned long msize;
 122                 unsigned long tbuffer;
 123                 if (mem->map[i].type != LB_MEM_RAM)
 124                         continue;
 125                 if (unpack_lb64(mem->map[i].start) > MAX_ADDR)
 126                         continue;
 127                 if (unpack_lb64(mem->map[i].size) < lb_size)
 128                         continue;
 129                 mstart = unpack_lb64(mem->map[i].start);
 130                 msize = MAX_ADDR - mstart +1;
 131                 if (msize > unpack_lb64(mem->map[i].size))
 132                         msize = unpack_lb64(mem->map[i].size);
 133                 mend = mstart + msize;
 134                 tbuffer = mend - lb_size;
 135                 if (tbuffer < buffer)
 136                         continue;
 137                 buffer = tbuffer;
 138         }
 139         bounce_buffer = buffer;
 140         bounce_size = req_size;
 141 }
 142
 143 static int valid_area(struct lb_memory *mem, unsigned long buffer,
 144         unsigned long start, unsigned long len)
 145 {
 146         /* Check through all of the memory segments and ensure
 147          * the segment that was passed in is completely contained
 148          * in RAM.
 149          */
 150         int i;
 151         unsigned long end = start + len;
 152         unsigned long mem_entries = (mem->size - sizeof(*mem))/sizeof(mem->map[0]);
 153
 154         /* See if I conflict with the bounce buffer */
 155         if (end >= buffer) {
 156                 return 0;
 157         }
 158
 159         /* Walk through the table of valid memory ranges and see if I
 160          * have a match.
 161          */
 162         for(i = 0; i < mem_entries; i++) {
 163                 uint64_t mstart, mend;
 164                 uint32_t mtype;
 165                 mtype = mem->map[i].type;
 166                 mstart = unpack_lb64(mem->map[i].start);
 167                 mend = mstart + unpack_lb64(mem->map[i].size);
 168                 if ((mtype == LB_MEM_RAM) && (start < mend) && (end > mstart)) {
 169                         break;
 170                 }
 171                 if ((mtype == LB_MEM_TABLE) && (start < mend) && (end > mstart)) {
 172                         printk(BIOS_ERR, "Payload is overwriting coreboot tables.\n");
 173                         break;
 174                 }
 175         }
 176         if (i == mem_entries) {
 177                 printk(BIOS_ERR, "No matching ram area found for range:\n");
 178                 printk(BIOS_ERR, "  [0x%016lx, 0x%016lx)\n", start, end);
 179                 printk(BIOS_ERR, "Ram areas\n");
 180                 for(i = 0; i < mem_entries; i++) {
 181                         uint64_t mstart, mend;
 182                         uint32_t mtype;
 183                         mtype = mem->map[i].type;
 184                         mstart = unpack_lb64(mem->map[i].start);
 185                         mend = mstart + unpack_lb64(mem->map[i].size);
 186                         printk(BIOS_ERR, "  [0x%016lx, 0x%016lx) %s\n",
 187                                 (unsigned long)mstart,
 188                                 (unsigned long)mend,
 189                                 (mtype == LB_MEM_RAM)?"RAM":"Reserved");
 190
 191                 }
 192                 return 0;
 193         }
 194         return 1;
 195 }
 196
 197 static const unsigned long lb_start = (unsigned long)&_ram_seg;
 198 static const unsigned long lb_end = (unsigned long)&_eram_seg;
 199
 200 static int overlaps_coreboot(struct segment *seg)
 201 {
 202         unsigned long start, end;
 203         start = seg->s_dstaddr;
 204         end = start + seg->s_memsz;
 205         return !((end <= lb_start) || (start >= lb_end));
 206 }
 207
 208 static int relocate_segment(unsigned long buffer, struct segment *seg)
 209 {
 210         /* Modify all segments that want to load onto coreboot
 211          * to load onto the bounce buffer instead.
 212          */
 213         /* ret:  1 : A new segment is inserted before the seg.
 214          *       0 : A new segment is inserted after the seg, or no new one. */
 215         unsigned long start, middle, end, ret = 0;
 216
 217         printk(BIOS_SPEW, "lb: [0x%016lx, 0x%016lx)\n",
 218                 lb_start, lb_end);
 219
 220         /* I don't conflict with coreboot so get out of here */
 221         if (!overlaps_coreboot(seg))
 222                 return 0;
 223
 224         start = seg->s_dstaddr;
 225         middle = start + seg->s_filesz;
 226         end = start + seg->s_memsz;
 227
 228         printk(BIOS_SPEW, "segment: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 229                 start, middle, end);
 230
 231         if (seg->compression == CBFS_COMPRESS_NONE) {
 232                 /* Slice off a piece at the beginning
 233                  * that doesn't conflict with coreboot.
 234                  */
 235                 if (start < lb_start) {
 236                         struct segment *new;
 237                         unsigned long len = lb_start - start;
 238                         new = malloc(sizeof(*new));
 239                         *new = *seg;
 240                         new->s_memsz = len;
 241                         seg->s_memsz -= len;
 242                         seg->s_dstaddr += len;
 243                         seg->s_srcaddr += len;
 244                         if (seg->s_filesz > len) {
 245                                 new->s_filesz = len;
 246                                 seg->s_filesz -= len;
 247                         } else {
 248                                 seg->s_filesz = 0;
 249                         }
 250
 251                         /* Order by stream offset */
 252                         new->next = seg;
 253                         new->prev = seg->prev;
 254                         seg->prev->next = new;
 255                         seg->prev = new;
 256                         /* Order by original program header order */
 257                         new->phdr_next = seg;
 258                         new->phdr_prev = seg->phdr_prev;
 259                         seg->phdr_prev->phdr_next = new;
 260                         seg->phdr_prev = new;
 261
 262                         /* compute the new value of start */
 263                         start = seg->s_dstaddr;
 264
 265                         printk(BIOS_SPEW, "   early: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 266                                 new->s_dstaddr,
 267                                 new->s_dstaddr + new->s_filesz,
 268                                 new->s_dstaddr + new->s_memsz);
 269
 270                         ret = 1;
 271                 }
 272
 273                 /* Slice off a piece at the end
 274                  * that doesn't conflict with coreboot
 275                  */
 276                 if (end > lb_end) {
 277                         unsigned long len = lb_end - start;
 278                         struct segment *new;
 279                         new = malloc(sizeof(*new));
 280                         *new = *seg;
 281                         seg->s_memsz = len;
 282                         new->s_memsz -= len;
 283                         new->s_dstaddr += len;
 284                         new->s_srcaddr += len;
 285                         if (seg->s_filesz > len) {
 286                                 seg->s_filesz = len;
 287                                 new->s_filesz -= len;
 288                         } else {
 289                                 new->s_filesz = 0;
 290                         }
 291                         /* Order by stream offset */
 292                         new->next = seg->next;
 293                         new->prev = seg;
 294                         seg->next->prev = new;
 295                         seg->next = new;
 296                         /* Order by original program header order */
 297                         new->phdr_next = seg->phdr_next;
 298                         new->phdr_prev = seg;
 299                         seg->phdr_next->phdr_prev = new;
 300                         seg->phdr_next = new;
 301
 302                         printk(BIOS_SPEW, "   late: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 303                                 new->s_dstaddr,
 304                                 new->s_dstaddr + new->s_filesz,
 305                                 new->s_dstaddr + new->s_memsz);
 306                 }
 307         }
 308
 309         /* Now retarget this segment onto the bounce buffer */
 310         /* sort of explanation: the buffer is a 1:1 mapping to coreboot.
 311          * so you will make the dstaddr be this buffer, and it will get copied
 312          * later to where coreboot lives.
 313          */
 314         seg->s_dstaddr = buffer + (seg->s_dstaddr - lb_start);
 315
 316         printk(BIOS_SPEW, " bounce: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 317                 seg->s_dstaddr,
 318                 seg->s_dstaddr + seg->s_filesz,
 319                 seg->s_dstaddr + seg->s_memsz);
 320
 321         return ret;
 322 }
 323
 324
 325 static int build_self_segment_list(
 326         struct segment *head,
 327         struct lb_memory *mem,
 328         struct cbfs_payload *payload, u32 *entry)
 329 {
 330         struct segment *new;
 331         struct segment *ptr;
 332         struct cbfs_payload_segment *segment, *first_segment;
 333         memset(head, 0, sizeof(*head));
 334         head->phdr_next = head->phdr_prev = head;
 335         head->next = head->prev = head;
 336         first_segment = segment = &payload->segments;
 337
 338         while(1) {
 339                 printk(BIOS_DEBUG, "Loading segment from rom address 0x%p\n", segment);
 340                 switch(segment->type) {
 341                 case PAYLOAD_SEGMENT_PARAMS:
 342                         printk(BIOS_DEBUG, "  parameter section (skipped)\n");
 343                         segment++;
 344                         continue;
 345
 346                 case PAYLOAD_SEGMENT_CODE:
 347                 case PAYLOAD_SEGMENT_DATA:
 348                         printk(BIOS_DEBUG, "  %s (compression=%x)\n",
 349                                         segment->type == PAYLOAD_SEGMENT_CODE ?  "code" : "data",
 350                                         ntohl(segment->compression));
 351                         new = malloc(sizeof(*new));
 352                         new->s_dstaddr = ntohll(segment->load_addr);
 353                         new->s_memsz = ntohl(segment->mem_len);
 354                         new->compression = ntohl(segment->compression);
 355
 356                         new->s_srcaddr = (u32) ((unsigned char *)first_segment)
 357                                                 + ntohl(segment->offset);
 358                         new->s_filesz = ntohl(segment->len);
 359                         printk(BIOS_DEBUG, "  New segment dstaddr 0x%lx memsize 0x%lx srcaddr 0x%lx filesize 0x%lx\n",
 360                                 new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
 361                         /* Clean up the values */
 362                         if (new->s_filesz > new->s_memsz)  {
 363                                 new->s_filesz = new->s_memsz;
 364                         }
 365                         printk(BIOS_DEBUG, "  (cleaned up) New segment addr 0x%lx size 0x%lx offset 0x%lx filesize 0x%lx\n",
 366                                 new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
 367                         break;
 368
 369                 case PAYLOAD_SEGMENT_BSS:
 370                         printk(BIOS_DEBUG, "  BSS 0x%p (%d byte)\n", (void *)
 371                                         (intptr_t)ntohll(segment->load_addr),
 372                                         ntohl(segment->mem_len));
 373                         new = malloc(sizeof(*new));
 374                         new->s_filesz = 0;
 375                         new->s_dstaddr = ntohll(segment->load_addr);
 376                         new->s_memsz = ntohl(segment->mem_len);
 377                         break;
 378
 379                 case PAYLOAD_SEGMENT_ENTRY:
 380                         printk(BIOS_DEBUG, "  Entry Point 0x%p\n", (void *) ntohl((u32) segment->load_addr));
 381                         *entry =  ntohll(segment->load_addr);
 382                         /* Per definition, a payload always has the entry point
 383                          * as last segment. Thus, we use the occurence of the
 384                          * entry point as break condition for the loop.
 385                          * Can we actually just look at the number of section?
 386                          */
 387                         return 1;
 388
 389                 default:
 390                         /* We found something that we don't know about. Throw
 391                          * hands into the sky and run away!
 392                          */
 393                         printk(BIOS_EMERG, "Bad segment type %x\n", segment->type);
 394                         return -1;
 395                 }
 396
 397                 segment++;
 398
 399                 // FIXME: Explain what this is
 400                 for(ptr = head->next; ptr != head; ptr = ptr->next) {
 401                         if (new->s_srcaddr < ntohll(segment->load_addr))
 402                                 break;
 403                 }
 404
 405                 /* Order by stream offset */
 406                 new->next = ptr;
 407                 new->prev = ptr->prev;
 408                 ptr->prev->next = new;
 409                 ptr->prev = new;
 410
 411                 /* Order by original program header order */
 412                 new->phdr_next = head;
 413                 new->phdr_prev = head->phdr_prev;
 414                 head->phdr_prev->phdr_next  = new;
 415                 head->phdr_prev = new;
 416         }
 417
 418         return 1;
 419 }
 420
 421 static int load_self_segments(
 422         struct segment *head,
 423         struct lb_memory *mem,
 424         struct cbfs_payload *payload)
 425 {
 426         struct segment *ptr;
 427
 428         unsigned long bounce_high = lb_end;
 429         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 430                 if (!overlaps_coreboot(ptr)) continue;
 431                 if (ptr->s_dstaddr + ptr->s_memsz > bounce_high)
 432                         bounce_high = ptr->s_dstaddr + ptr->s_memsz;
 433         }
 434         get_bounce_buffer(mem, bounce_high - lb_start);
 435         if (!bounce_buffer) {
 436                 printk(BIOS_ERR, "Could not find a bounce buffer...\n");
 437                 return 0;
 438         }
 439         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 440                 /* Verify the memory addresses in the segment are valid */
 441                 if (!valid_area(mem, bounce_buffer, ptr->s_dstaddr, ptr->s_memsz))
 442                         return 0;
 443         }
 444         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 445                 unsigned char *dest, *src;
 446                 printk(BIOS_DEBUG, "Loading Segment: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
 447                         ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);
 448
 449                 /* Modify the segment to load onto the bounce_buffer if necessary.
 450                  */
 451                 if (relocate_segment(bounce_buffer, ptr)) {
 452                         ptr = (ptr->prev)->prev;
 453                         continue;
 454                 }
 455
 456                 printk(BIOS_DEBUG, "Post relocation: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
 457                         ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);
 458
 459                 /* Compute the boundaries of the segment */
 460                 dest = (unsigned char *)(ptr->s_dstaddr);
 461                 src = (unsigned char *)(ptr->s_srcaddr);
 462
 463                 /* Copy data from the initial buffer */
 464                 if (ptr->s_filesz) {
 465                         unsigned char *middle, *end;
 466                         size_t len;
 467                         len = ptr->s_filesz;
 468                         switch(ptr->compression) {
 469                                 case CBFS_COMPRESS_LZMA: {
 470                                         printk(BIOS_DEBUG, "using LZMA\n");
 471                                         len = ulzma(src, dest);
 472                                         if (!len) /* Decompression Error. */
 473                                                 return 0;
 474                                         break;
 475                                 }
 476 #if CONFIG_COMPRESSED_PAYLOAD_NRV2B
 477                                 case CBFS_COMPRESS_NRV2B: {
 478                                         printk(BIOS_DEBUG, "using NRV2B\n");
 479                                         unsigned long unrv2b(u8 *src, u8 *dst, unsigned long *ilen_p);
 480                                         unsigned long tmp;
 481                                         len = unrv2b(src, dest, &tmp);
 482                                         break;
 483                                 }
 484 #endif
 485                                 case CBFS_COMPRESS_NONE: {
 486                                         printk(BIOS_DEBUG, "it's not compressed!\n");
 487                                         memcpy(dest, src, len);
 488                                         break;
 489                                 }
 490                                 default:
 491                                         printk(BIOS_INFO,  "CBFS:  Unknown compression type %d\n", ptr->compression);
 492                                         return -1;
 493                         }
 494                         end = dest + ptr->s_memsz;
 495                         middle = dest + len;
 496                         printk(BIOS_SPEW, "[ 0x%08lx, %08lx, 0x%08lx) <- %08lx\n",
 497                                 (unsigned long)dest,
 498                                 (unsigned long)middle,
 499                                 (unsigned long)end,
 500                                 (unsigned long)src);
 501
 502                         /* Zero the extra bytes between middle & end */
 503                         if (middle < end) {
 504                                 printk(BIOS_DEBUG, "Clearing Segment: addr: 0x%016lx memsz: 0x%016lx\n",
 505                                         (unsigned long)middle, (unsigned long)(end - middle));
 506
 507                                 /* Zero the extra bytes */
 508                                 memset(middle, 0, end - middle);
 509                         }
 510                         /* Copy the data that's outside the area that shadows coreboot_ram */
 511                         printk(BIOS_DEBUG, "dest %p, end %p, bouncebuffer %lx\n", dest, end, bounce_buffer);
 512                         if ((unsigned long)end > bounce_buffer) {
 513                                 if ((unsigned long)dest < bounce_buffer) {
 514                                         unsigned char *from = dest;
 515                                         unsigned char *to = (unsigned char*)(lb_start-(bounce_buffer-(unsigned long)dest));
 516                                         unsigned long amount = bounce_buffer-(unsigned long)dest;
 517                                         printk(BIOS_DEBUG, "move prefix around: from %p, to %p, amount: %lx\n", from, to, amount);
 518                                         memcpy(to, from, amount);
 519                                 }
 520                                 if ((unsigned long)end > bounce_buffer + (lb_end - lb_start)) {
 521                                         unsigned long from = bounce_buffer + (lb_end - lb_start);
 522                                         unsigned long to = lb_end;
 523                                         unsigned long amount = (unsigned long)end - from;
 524                                         printk(BIOS_DEBUG, "move suffix around: from %lx, to %lx, amount: %lx\n", from, to, amount);
 525                                         memcpy((char*)to, (char*)from, amount);
 526                                 }
 527                         }
 528                 }
 529         }
 530         return 1;
 531 }
 532
 533 static int selfboot(struct lb_memory *mem, struct cbfs_payload *payload)
 534 {
 535         u32 entry=0;
 536         struct segment head;
 537
 538         /* Preprocess the self segments */
 539         if (!build_self_segment_list(&head, mem, payload, &entry))
 540                 goto out;
 541
 542         /* Load the segments */
 543         if (!load_self_segments(&head, mem, payload))
 544                 goto out;
 545
 546         printk(BIOS_SPEW, "Loaded segments\n");
 547
 548         /* Reset to booting from this image as late as possible */
 549         boot_successful();
 550
 551         printk(BIOS_DEBUG, "Jumping to boot code at %x\n", entry);
 552         post_code(POST_ENTER_ELF_BOOT);
 553
 554         /* Jump to kernel */
 555         jmp_to_elf_entry((void*)entry, bounce_buffer, bounce_size);
 556         return 1;
 557
 558  out:
 559         return 0;
 560 }
 561