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         struct segment *phdr_next;
  49         struct segment *phdr_prev;
  50         unsigned long s_dstaddr;
  51         unsigned long s_srcaddr;
  52         unsigned long s_memsz;
  53         unsigned long s_filesz;
  54         int compression;
  55 };
  56
  57 /* The problem:
  58  * Static executables all want to share the same addresses
  59  * in memory because only a few addresses are reliably present on
  60  * a machine, and implementing general relocation is hard.
  61  *
  62  * The solution:
  63  * - Allocate a buffer the size of the coreboot image plus additional
  64  *   required space.
  65  * - Anything that would overwrite coreboot copy into the lower part of
  66  *   the buffer.
  67  * - After loading an ELF image copy coreboot to the top of the buffer.
  68  * - Then jump to the loaded image.
  69  *
  70  * Benefits:
  71  * - Nearly arbitrary standalone executables can be loaded.
  72  * - Coreboot is preserved, so it can be returned to.
  73  * - The implementation is still relatively simple,
  74  *   and much simpler than the general case implemented in kexec.
  75  */
  76
  77 static unsigned long bounce_size, bounce_buffer;
  78
  79 static void get_bounce_buffer(struct lb_memory *mem, unsigned long req_size)
  80 {
  81         unsigned long lb_size;
  82         unsigned long mem_entries;
  83         unsigned long buffer;
  84         int i;
  85         lb_size = lb_end - lb_start;
  86         /* Plus coreboot size so I have somewhere
  87          * to place a copy to return to.
  88          */
  89         lb_size = req_size + lb_size;
  90         mem_entries = (mem->size - sizeof(*mem)) / sizeof(mem->map[0]);
  91         buffer = 0;
  92         for(i = 0; i < mem_entries; i++) {
  93                 unsigned long mstart, mend;
  94                 unsigned long msize;
  95                 unsigned long tbuffer;
  96                 if (mem->map[i].type != LB_MEM_RAM)
  97                         continue;
  98                 if (unpack_lb64(mem->map[i].start) > MAX_ADDR)
  99                         continue;
 100                 if (unpack_lb64(mem->map[i].size) < lb_size)
 101                         continue;
 102                 mstart = unpack_lb64(mem->map[i].start);
 103                 msize = MAX_ADDR - mstart +1;
 104                 if (msize > unpack_lb64(mem->map[i].size))
 105                         msize = unpack_lb64(mem->map[i].size);
 106                 mend = mstart + msize;
 107                 tbuffer = mend - lb_size;
 108                 if (tbuffer < buffer)
 109                         continue;
 110                 buffer = tbuffer;
 111         }
 112         bounce_buffer = buffer;
 113         bounce_size = req_size;
 114 }
 115
 116 static int valid_area(struct lb_memory *mem, unsigned long buffer,
 117         unsigned long start, unsigned long len)
 118 {
 119         /* Check through all of the memory segments and ensure
 120          * the segment that was passed in is completely contained
 121          * in RAM.
 122          */
 123         int i;
 124         unsigned long end = start + len;
 125         unsigned long mem_entries = (mem->size - sizeof(*mem)) /
 126                 sizeof(mem->map[0]);
 127
 128         /* See if I conflict with the bounce buffer */
 129         if (end >= buffer) {
 130                 return 0;
 131         }
 132
 133         /* Walk through the table of valid memory ranges and see if I
 134          * have a match.
 135          */
 136         for(i = 0; i < mem_entries; i++) {
 137                 uint64_t mstart, mend;
 138                 uint32_t mtype;
 139                 mtype = mem->map[i].type;
 140                 mstart = unpack_lb64(mem->map[i].start);
 141                 mend = mstart + unpack_lb64(mem->map[i].size);
 142                 if ((mtype == LB_MEM_RAM) && (start >= mstart) && (end < mend)) {
 143                         break;
 144                 }
 145                 if ((mtype == LB_MEM_TABLE) && (start >= mstart) && (end < mend)) {
 146                         printk(BIOS_ERR, "Payload is overwriting coreboot tables.\n");
 147                         break;
 148                 }
 149         }
 150         if (i == mem_entries) {
 151                 printk(BIOS_ERR, "No matching ram area found for range:\n");
 152                 printk(BIOS_ERR, "  [0x%016lx, 0x%016lx)\n", start, end);
 153                 printk(BIOS_ERR, "Ram areas\n");
 154                 for(i = 0; i < mem_entries; i++) {
 155                         uint64_t mstart, mend;
 156                         uint32_t mtype;
 157                         mtype = mem->map[i].type;
 158                         mstart = unpack_lb64(mem->map[i].start);
 159                         mend = mstart + unpack_lb64(mem->map[i].size);
 160                         printk(BIOS_ERR, "  [0x%016lx, 0x%016lx) %s\n",
 161                                 (unsigned long)mstart,
 162                                 (unsigned long)mend,
 163                                 (mtype == LB_MEM_RAM)?"RAM":"Reserved");
 164
 165                 }
 166                 return 0;
 167         }
 168         return 1;
 169 }
 170
 171
 172 static int overlaps_coreboot(struct segment *seg)
 173 {
 174         unsigned long start, end;
 175         start = seg->s_dstaddr;
 176         end = start + seg->s_memsz;
 177         return !((end <= lb_start) || (start >= lb_end));
 178 }
 179
 180 static int relocate_segment(unsigned long buffer, struct segment *seg)
 181 {
 182         /* Modify all segments that want to load onto coreboot
 183          * to load onto the bounce buffer instead.
 184          */
 185         /* ret:  1 : A new segment is inserted before the seg.
 186          *       0 : A new segment is inserted after the seg, or no new one.
 187          */
 188         unsigned long start, middle, end, ret = 0;
 189
 190         printk(BIOS_SPEW, "lb: [0x%016lx, 0x%016lx)\n",
 191                 lb_start, lb_end);
 192
 193         /* I don't conflict with coreboot so get out of here */
 194         if (!overlaps_coreboot(seg))
 195                 return 0;
 196
 197         start = seg->s_dstaddr;
 198         middle = start + seg->s_filesz;
 199         end = start + seg->s_memsz;
 200
 201         printk(BIOS_SPEW, "segment: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 202                 start, middle, end);
 203
 204         if (seg->compression == CBFS_COMPRESS_NONE) {
 205                 /* Slice off a piece at the beginning
 206                  * that doesn't conflict with coreboot.
 207                  */
 208                 if (start < lb_start) {
 209                         struct segment *new;
 210                         unsigned long len = lb_start - start;
 211                         new = malloc(sizeof(*new));
 212                         *new = *seg;
 213                         new->s_memsz = len;
 214                         seg->s_memsz -= len;
 215                         seg->s_dstaddr += len;
 216                         seg->s_srcaddr += len;
 217                         if (seg->s_filesz > len) {
 218                                 new->s_filesz = len;
 219                                 seg->s_filesz -= len;
 220                         } else {
 221                                 seg->s_filesz = 0;
 222                         }
 223
 224                         /* Order by stream offset */
 225                         new->next = seg;
 226                         new->prev = seg->prev;
 227                         seg->prev->next = new;
 228                         seg->prev = new;
 229                         /* Order by original program header order */
 230                         new->phdr_next = seg;
 231                         new->phdr_prev = seg->phdr_prev;
 232                         seg->phdr_prev->phdr_next = new;
 233                         seg->phdr_prev = new;
 234
 235                         /* compute the new value of start */
 236                         start = seg->s_dstaddr;
 237
 238                         printk(BIOS_SPEW, "   early: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 239                                 new->s_dstaddr,
 240                                 new->s_dstaddr + new->s_filesz,
 241                                 new->s_dstaddr + new->s_memsz);
 242
 243                         ret = 1;
 244                 }
 245
 246                 /* Slice off a piece at the end
 247                  * that doesn't conflict with coreboot
 248                  */
 249                 if (end > lb_end) {
 250                         unsigned long len = lb_end - start;
 251                         struct segment *new;
 252                         new = malloc(sizeof(*new));
 253                         *new = *seg;
 254                         seg->s_memsz = len;
 255                         new->s_memsz -= len;
 256                         new->s_dstaddr += len;
 257                         new->s_srcaddr += len;
 258                         if (seg->s_filesz > len) {
 259                                 seg->s_filesz = len;
 260                                 new->s_filesz -= len;
 261                         } else {
 262                                 new->s_filesz = 0;
 263                         }
 264                         /* Order by stream offset */
 265                         new->next = seg->next;
 266                         new->prev = seg;
 267                         seg->next->prev = new;
 268                         seg->next = new;
 269                         /* Order by original program header order */
 270                         new->phdr_next = seg->phdr_next;
 271                         new->phdr_prev = seg;
 272                         seg->phdr_next->phdr_prev = new;
 273                         seg->phdr_next = new;
 274
 275                         printk(BIOS_SPEW, "   late: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 276                                 new->s_dstaddr,
 277                                 new->s_dstaddr + new->s_filesz,
 278                                 new->s_dstaddr + new->s_memsz);
 279                 }
 280         }
 281
 282         /* Now retarget this segment onto the bounce buffer */
 283         /* sort of explanation: the buffer is a 1:1 mapping to coreboot.
 284          * so you will make the dstaddr be this buffer, and it will get copied
 285          * later to where coreboot lives.
 286          */
 287         seg->s_dstaddr = buffer + (seg->s_dstaddr - lb_start);
 288
 289         printk(BIOS_SPEW, " bounce: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 290                 seg->s_dstaddr,
 291                 seg->s_dstaddr + seg->s_filesz,
 292                 seg->s_dstaddr + seg->s_memsz);
 293
 294         return ret;
 295 }
 296
 297
 298 static int build_self_segment_list(
 299         struct segment *head,
 300         struct lb_memory *mem,
 301         struct cbfs_payload *payload, u32 *entry)
 302 {
 303         struct segment *new;
 304         struct segment *ptr;
 305         struct cbfs_payload_segment *segment, *first_segment;
 306         memset(head, 0, sizeof(*head));
 307         head->phdr_next = head->phdr_prev = head;
 308         head->next = head->prev = head;
 309         first_segment = segment = &payload->segments;
 310
 311         while(1) {
 312                 printk(BIOS_DEBUG, "Loading segment from rom address 0x%p\n", segment);
 313                 switch(segment->type) {
 314                 case PAYLOAD_SEGMENT_PARAMS:
 315                         printk(BIOS_DEBUG, "  parameter section (skipped)\n");
 316                         segment++;
 317                         continue;
 318
 319                 case PAYLOAD_SEGMENT_CODE:
 320                 case PAYLOAD_SEGMENT_DATA:
 321                         printk(BIOS_DEBUG, "  %s (compression=%x)\n",
 322                                         segment->type == PAYLOAD_SEGMENT_CODE ?  "code" : "data",
 323                                         ntohl(segment->compression));
 324                         new = malloc(sizeof(*new));
 325                         new->s_dstaddr = ntohll(segment->load_addr);
 326                         new->s_memsz = ntohl(segment->mem_len);
 327                         new->compression = ntohl(segment->compression);
 328
 329                         new->s_srcaddr = (u32) ((unsigned char *)first_segment)
 330                                                 + ntohl(segment->offset);
 331                         new->s_filesz = ntohl(segment->len);
 332                         printk(BIOS_DEBUG, "  New segment dstaddr 0x%lx memsize 0x%lx srcaddr 0x%lx filesize 0x%lx\n",
 333                                 new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
 334                         /* Clean up the values */
 335                         if (new->s_filesz > new->s_memsz)  {
 336                                 new->s_filesz = new->s_memsz;
 337                         }
 338                         printk(BIOS_DEBUG, "  (cleaned up) New segment addr 0x%lx size 0x%lx offset 0x%lx filesize 0x%lx\n",
 339                                 new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
 340                         break;
 341
 342                 case PAYLOAD_SEGMENT_BSS:
 343                         printk(BIOS_DEBUG, "  BSS 0x%p (%d byte)\n", (void *)
 344                                         (intptr_t)ntohll(segment->load_addr),
 345                                         ntohl(segment->mem_len));
 346                         new = malloc(sizeof(*new));
 347                         new->s_filesz = 0;
 348                         new->s_dstaddr = ntohll(segment->load_addr);
 349                         new->s_memsz = ntohl(segment->mem_len);
 350                         break;
 351
 352                 case PAYLOAD_SEGMENT_ENTRY:
 353                         printk(BIOS_DEBUG, "  Entry Point 0x%p\n", (void *) ntohl((u32) segment->load_addr));
 354                         *entry =  ntohll(segment->load_addr);
 355                         /* Per definition, a payload always has the entry point
 356                          * as last segment. Thus, we use the occurence of the
 357                          * entry point as break condition for the loop.
 358                          * Can we actually just look at the number of section?
 359                          */
 360                         return 1;
 361
 362                 default:
 363                         /* We found something that we don't know about. Throw
 364                          * hands into the sky and run away!
 365                          */
 366                         printk(BIOS_EMERG, "Bad segment type %x\n", segment->type);
 367                         return -1;
 368                 }
 369
 370                 segment++;
 371
 372                 // FIXME: Explain what this is
 373                 for(ptr = head->next; ptr != head; ptr = ptr->next) {
 374                         if (new->s_srcaddr < ntohll(segment->load_addr))
 375                                 break;
 376                 }
 377
 378                 /* Order by stream offset */
 379                 new->next = ptr;
 380                 new->prev = ptr->prev;
 381                 ptr->prev->next = new;
 382                 ptr->prev = new;
 383
 384                 /* Order by original program header order */
 385                 new->phdr_next = head;
 386                 new->phdr_prev = head->phdr_prev;
 387                 head->phdr_prev->phdr_next  = new;
 388                 head->phdr_prev = new;
 389         }
 390
 391         return 1;
 392 }
 393
 394 static int load_self_segments(
 395         struct segment *head,
 396         struct lb_memory *mem,
 397         struct cbfs_payload *payload)
 398 {
 399         struct segment *ptr;
 400
 401         unsigned long bounce_high = lb_end;
 402         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 403                 if (!overlaps_coreboot(ptr)) continue;
 404                 if (ptr->s_dstaddr + ptr->s_memsz > bounce_high)
 405                         bounce_high = ptr->s_dstaddr + ptr->s_memsz;
 406         }
 407         get_bounce_buffer(mem, bounce_high - lb_start);
 408         if (!bounce_buffer) {
 409                 printk(BIOS_ERR, "Could not find a bounce buffer...\n");
 410                 return 0;
 411         }
 412         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 413                 /* Verify the memory addresses in the segment are valid */
 414                 if (!valid_area(mem, bounce_buffer, ptr->s_dstaddr, ptr->s_memsz))
 415                         return 0;
 416         }
 417         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 418                 unsigned char *dest, *src;
 419                 printk(BIOS_DEBUG, "Loading Segment: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
 420                         ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);
 421
 422                 /* Modify the segment to load onto the bounce_buffer if necessary.
 423                  */
 424                 if (relocate_segment(bounce_buffer, ptr)) {
 425                         ptr = (ptr->prev)->prev;
 426                         continue;
 427                 }
 428
 429                 printk(BIOS_DEBUG, "Post relocation: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
 430                         ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);
 431
 432                 /* Compute the boundaries of the segment */
 433                 dest = (unsigned char *)(ptr->s_dstaddr);
 434                 src = (unsigned char *)(ptr->s_srcaddr);
 435
 436                 /* Copy data from the initial buffer */
 437                 if (ptr->s_filesz) {
 438                         unsigned char *middle, *end;
 439                         size_t len;
 440                         len = ptr->s_filesz;
 441                         switch(ptr->compression) {
 442                                 case CBFS_COMPRESS_LZMA: {
 443                                         printk(BIOS_DEBUG, "using LZMA\n");
 444                                         len = ulzma(src, dest);
 445                                         if (!len) /* Decompression Error. */
 446                                                 return 0;
 447                                         break;
 448                                 }
 449 #if CONFIG_COMPRESSED_PAYLOAD_NRV2B
 450                                 case CBFS_COMPRESS_NRV2B: {
 451                                         printk(BIOS_DEBUG, "using NRV2B\n");
 452                                         unsigned long unrv2b(u8 *src, u8 *dst, unsigned long *ilen_p);
 453                                         unsigned long tmp;
 454                                         len = unrv2b(src, dest, &tmp);
 455                                         break;
 456                                 }
 457 #endif
 458                                 case CBFS_COMPRESS_NONE: {
 459                                         printk(BIOS_DEBUG, "it's not compressed!\n");
 460                                         memcpy(dest, src, len);
 461                                         break;
 462                                 }
 463                                 default:
 464                                         printk(BIOS_INFO,  "CBFS:  Unknown compression type %d\n", ptr->compression);
 465                                         return -1;
 466                         }
 467                         end = dest + ptr->s_memsz;
 468                         middle = dest + len;
 469                         printk(BIOS_SPEW, "[ 0x%08lx, %08lx, 0x%08lx) <- %08lx\n",
 470                                 (unsigned long)dest,
 471                                 (unsigned long)middle,
 472                                 (unsigned long)end,
 473                                 (unsigned long)src);
 474
 475                         /* Zero the extra bytes between middle & end */
 476                         if (middle < end) {
 477                                 printk(BIOS_DEBUG, "Clearing Segment: addr: 0x%016lx memsz: 0x%016lx\n",
 478                                         (unsigned long)middle, (unsigned long)(end - middle));
 479
 480                                 /* Zero the extra bytes */
 481                                 memset(middle, 0, end - middle);
 482                         }
 483                         /* Copy the data that's outside the area that shadows coreboot_ram */
 484                         printk(BIOS_DEBUG, "dest %p, end %p, bouncebuffer %lx\n", dest, end, bounce_buffer);
 485                         if ((unsigned long)end > bounce_buffer) {
 486                                 if ((unsigned long)dest < bounce_buffer) {
 487                                         unsigned char *from = dest;
 488                                         unsigned char *to = (unsigned char*)(lb_start-(bounce_buffer-(unsigned long)dest));
 489                                         unsigned long amount = bounce_buffer-(unsigned long)dest;
 490                                         printk(BIOS_DEBUG, "move prefix around: from %p, to %p, amount: %lx\n", from, to, amount);
 491                                         memcpy(to, from, amount);
 492                                 }
 493                                 if ((unsigned long)end > bounce_buffer + (lb_end - lb_start)) {
 494                                         unsigned long from = bounce_buffer + (lb_end - lb_start);
 495                                         unsigned long to = lb_end;
 496                                         unsigned long amount = (unsigned long)end - from;
 497                                         printk(BIOS_DEBUG, "move suffix around: from %lx, to %lx, amount: %lx\n", from, to, amount);
 498                                         memcpy((char*)to, (char*)from, amount);
 499                                 }
 500                         }
 501                 }
 502         }
 503         return 1;
 504 }
 505
 506 static int selfboot(struct lb_memory *mem, struct cbfs_payload *payload)
 507 {
 508         u32 entry=0;
 509         struct segment head;
 510
 511         /* Preprocess the self segments */
 512         if (!build_self_segment_list(&head, mem, payload, &entry))
 513                 goto out;
 514
 515         /* Load the segments */
 516         if (!load_self_segments(&head, mem, payload))
 517                 goto out;
 518
 519         printk(BIOS_SPEW, "Loaded segments\n");
 520
 521         /* Reset to booting from this image as late as possible */
 522         boot_successful();
 523
 524         printk(BIOS_DEBUG, "Jumping to boot code at %x\n", entry);
 525         post_code(POST_ENTER_ELF_BOOT);
 526
 527         /* Jump to kernel */
 528         jmp_to_elf_entry((void*)entry, bounce_buffer, bounce_size);
 529         return 1;
 530
 531  out:
 532         return 0;
 533 }
 534
 535 void *cbfs_load_payload(struct lb_memory *lb_mem, const char *name)
 536 {
 537         struct cbfs_payload *payload;
 538
 539         payload = (struct cbfs_payload *)cbfs_find_file(name, CBFS_TYPE_PAYLOAD);
 540         if (payload == NULL)
 541                 return (void *) -1;
 542         printk(BIOS_DEBUG, "Got a payload\n");
 543
 544         selfboot(lb_mem, payload);
 545         printk(BIOS_EMERG, "SELFBOOT RETURNED!\n");
 546
 547         return (void *) -1;
 548 }
 549