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