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                 printk(BIOS_ERR, "No matching ram area found for range:\n");
 150                 printk(BIOS_ERR, "  [0x%016lx, 0x%016lx)\n", start, end);
 151                 printk(BIOS_ERR, "Ram areas\n");
 152                 for(i = 0; i < mem_entries; i++) {
 153                         uint64_t mstart, mend;
 154                         uint32_t mtype;
 155                         mtype = mem->map[i].type;
 156                         mstart = unpack_lb64(mem->map[i].start);
 157                         mend = mstart + unpack_lb64(mem->map[i].size);
 158                         printk(BIOS_ERR, "  [0x%016lx, 0x%016lx) %s\n",
 159                                 (unsigned long)mstart,
 160                                 (unsigned long)mend,
 161                                 (mtype == LB_MEM_RAM)?"RAM":"Reserved");
 162
 163                 }
 164                 return 0;
 165         }
 166         return 1;
 167 }
 168
 169
 170 static int overlaps_coreboot(struct segment *seg)
 171 {
 172         unsigned long start, end;
 173         start = seg->s_dstaddr;
 174         end = start + seg->s_memsz;
 175         return !((end <= lb_start) || (start >= lb_end));
 176 }
 177
 178 static int relocate_segment(unsigned long buffer, struct segment *seg)
 179 {
 180         /* Modify all segments that want to load onto coreboot
 181          * to load onto the bounce buffer instead.
 182          */
 183         /* ret:  1 : A new segment is inserted before the seg.
 184          *       0 : A new segment is inserted after the seg, or no new one.
 185          */
 186         unsigned long start, middle, end, ret = 0;
 187
 188         printk(BIOS_SPEW, "lb: [0x%016lx, 0x%016lx)\n",
 189                 lb_start, lb_end);
 190
 191         /* I don't conflict with coreboot so get out of here */
 192         if (!overlaps_coreboot(seg))
 193                 return 0;
 194
 195         start = seg->s_dstaddr;
 196         middle = start + seg->s_filesz;
 197         end = start + seg->s_memsz;
 198
 199         printk(BIOS_SPEW, "segment: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 200                 start, middle, end);
 201
 202         if (seg->compression == CBFS_COMPRESS_NONE) {
 203                 /* Slice off a piece at the beginning
 204                  * that doesn't conflict with coreboot.
 205                  */
 206                 if (start < lb_start) {
 207                         struct segment *new;
 208                         unsigned long len = lb_start - start;
 209                         new = malloc(sizeof(*new));
 210                         *new = *seg;
 211                         new->s_memsz = len;
 212                         seg->s_memsz -= len;
 213                         seg->s_dstaddr += len;
 214                         seg->s_srcaddr += len;
 215                         if (seg->s_filesz > len) {
 216                                 new->s_filesz = len;
 217                                 seg->s_filesz -= len;
 218                         } else {
 219                                 seg->s_filesz = 0;
 220                         }
 221
 222                         /* Order by stream offset */
 223                         new->next = seg;
 224                         new->prev = seg->prev;
 225                         seg->prev->next = new;
 226                         seg->prev = new;
 227
 228                         /* compute the new value of start */
 229                         start = seg->s_dstaddr;
 230
 231                         printk(BIOS_SPEW, "   early: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 232                                 new->s_dstaddr,
 233                                 new->s_dstaddr + new->s_filesz,
 234                                 new->s_dstaddr + new->s_memsz);
 235
 236                         ret = 1;
 237                 }
 238
 239                 /* Slice off a piece at the end
 240                  * that doesn't conflict with coreboot
 241                  */
 242                 if (end > lb_end) {
 243                         unsigned long len = lb_end - start;
 244                         struct segment *new;
 245                         new = malloc(sizeof(*new));
 246                         *new = *seg;
 247                         seg->s_memsz = len;
 248                         new->s_memsz -= len;
 249                         new->s_dstaddr += len;
 250                         new->s_srcaddr += len;
 251                         if (seg->s_filesz > len) {
 252                                 seg->s_filesz = len;
 253                                 new->s_filesz -= len;
 254                         } else {
 255                                 new->s_filesz = 0;
 256                         }
 257                         /* Order by stream offset */
 258                         new->next = seg->next;
 259                         new->prev = seg;
 260                         seg->next->prev = new;
 261                         seg->next = new;
 262
 263                         printk(BIOS_SPEW, "   late: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 264                                 new->s_dstaddr,
 265                                 new->s_dstaddr + new->s_filesz,
 266                                 new->s_dstaddr + new->s_memsz);
 267                 }
 268         }
 269
 270         /* Now retarget this segment onto the bounce buffer */
 271         /* sort of explanation: the buffer is a 1:1 mapping to coreboot.
 272          * so you will make the dstaddr be this buffer, and it will get copied
 273          * later to where coreboot lives.
 274          */
 275         seg->s_dstaddr = buffer + (seg->s_dstaddr - lb_start);
 276
 277         printk(BIOS_SPEW, " bounce: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 278                 seg->s_dstaddr,
 279                 seg->s_dstaddr + seg->s_filesz,
 280                 seg->s_dstaddr + seg->s_memsz);
 281
 282         return ret;
 283 }
 284
 285
 286 static int build_self_segment_list(
 287         struct segment *head,
 288         struct lb_memory *mem,
 289         struct cbfs_payload *payload, u32 *entry)
 290 {
 291         struct segment *new;
 292         struct segment *ptr;
 293         struct cbfs_payload_segment *segment, *first_segment;
 294         memset(head, 0, sizeof(*head));
 295         head->next = head->prev = head;
 296         first_segment = segment = &payload->segments;
 297
 298         while(1) {
 299                 printk(BIOS_DEBUG, "Loading segment from rom address 0x%p\n", segment);
 300                 switch(segment->type) {
 301                 case PAYLOAD_SEGMENT_PARAMS:
 302                         printk(BIOS_DEBUG, "  parameter section (skipped)\n");
 303                         segment++;
 304                         continue;
 305
 306                 case PAYLOAD_SEGMENT_CODE:
 307                 case PAYLOAD_SEGMENT_DATA:
 308                         printk(BIOS_DEBUG, "  %s (compression=%x)\n",
 309                                         segment->type == PAYLOAD_SEGMENT_CODE ?  "code" : "data",
 310                                         ntohl(segment->compression));
 311                         new = malloc(sizeof(*new));
 312                         new->s_dstaddr = ntohll(segment->load_addr);
 313                         new->s_memsz = ntohl(segment->mem_len);
 314                         new->compression = ntohl(segment->compression);
 315
 316                         new->s_srcaddr = (u32) ((unsigned char *)first_segment)
 317                                                 + ntohl(segment->offset);
 318                         new->s_filesz = ntohl(segment->len);
 319                         printk(BIOS_DEBUG, "  New segment dstaddr 0x%lx memsize 0x%lx srcaddr 0x%lx filesize 0x%lx\n",
 320                                 new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
 321                         /* Clean up the values */
 322                         if (new->s_filesz > new->s_memsz)  {
 323                                 new->s_filesz = new->s_memsz;
 324                         }
 325                         printk(BIOS_DEBUG, "  (cleaned up) New segment addr 0x%lx size 0x%lx offset 0x%lx filesize 0x%lx\n",
 326                                 new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
 327                         break;
 328
 329                 case PAYLOAD_SEGMENT_BSS:
 330                         printk(BIOS_DEBUG, "  BSS 0x%p (%d byte)\n", (void *)
 331                                         (intptr_t)ntohll(segment->load_addr),
 332                                         ntohl(segment->mem_len));
 333                         new = malloc(sizeof(*new));
 334                         new->s_filesz = 0;
 335                         new->s_dstaddr = ntohll(segment->load_addr);
 336                         new->s_memsz = ntohl(segment->mem_len);
 337                         break;
 338
 339                 case PAYLOAD_SEGMENT_ENTRY:
 340                         printk(BIOS_DEBUG, "  Entry Point 0x%p\n", (void *) ntohl((u32) segment->load_addr));
 341                         *entry =  ntohll(segment->load_addr);
 342                         /* Per definition, a payload always has the entry point
 343                          * as last segment. Thus, we use the occurence of the
 344                          * entry point as break condition for the loop.
 345                          * Can we actually just look at the number of section?
 346                          */
 347                         return 1;
 348
 349                 default:
 350                         /* We found something that we don't know about. Throw
 351                          * hands into the sky and run away!
 352                          */
 353                         printk(BIOS_EMERG, "Bad segment type %x\n", segment->type);
 354                         return -1;
 355                 }
 356
 357                 /* We have found another CODE, DATA or BSS segment */
 358                 segment++;
 359
 360                 /* Find place where to insert our segment */
 361                 for(ptr = head->next; ptr != head; ptr = ptr->next) {
 362                         if (new->s_srcaddr < ntohll(segment->load_addr))
 363                                 break;
 364                 }
 365
 366                 /* Order by stream offset */
 367                 new->next = ptr;
 368                 new->prev = ptr->prev;
 369                 ptr->prev->next = new;
 370                 ptr->prev = new;
 371         }
 372
 373         return 1;
 374 }
 375
 376 static int load_self_segments(
 377         struct segment *head,
 378         struct lb_memory *mem,
 379         struct cbfs_payload *payload)
 380 {
 381         struct segment *ptr;
 382
 383         unsigned long bounce_high = lb_end;
 384         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 385                 if (!overlaps_coreboot(ptr))
 386                         continue;
 387                 if (ptr->s_dstaddr + ptr->s_memsz > bounce_high)
 388                         bounce_high = ptr->s_dstaddr + ptr->s_memsz;
 389         }
 390         get_bounce_buffer(mem, bounce_high - lb_start);
 391         if (!bounce_buffer) {
 392                 printk(BIOS_ERR, "Could not find a bounce buffer...\n");
 393                 return 0;
 394         }
 395         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 396                 /* Verify the memory addresses in the segment are valid */
 397                 if (!valid_area(mem, bounce_buffer, ptr->s_dstaddr, ptr->s_memsz))
 398                         return 0;
 399         }
 400         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 401                 unsigned char *dest, *src;
 402                 printk(BIOS_DEBUG, "Loading Segment: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
 403                         ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);
 404
 405                 /* Modify the segment to load onto the bounce_buffer if necessary.
 406                  */
 407                 if (relocate_segment(bounce_buffer, ptr)) {
 408                         ptr = (ptr->prev)->prev;
 409                         continue;
 410                 }
 411
 412                 printk(BIOS_DEBUG, "Post relocation: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
 413                         ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);
 414
 415                 /* Compute the boundaries of the segment */
 416                 dest = (unsigned char *)(ptr->s_dstaddr);
 417                 src = (unsigned char *)(ptr->s_srcaddr);
 418
 419                 /* Copy data from the initial buffer */
 420                 if (ptr->s_filesz) {
 421                         unsigned char *middle, *end;
 422                         size_t len;
 423                         len = ptr->s_filesz;
 424                         switch(ptr->compression) {
 425                                 case CBFS_COMPRESS_LZMA: {
 426                                         printk(BIOS_DEBUG, "using LZMA\n");
 427                                         len = ulzma(src, dest);
 428                                         if (!len) /* Decompression Error. */
 429                                                 return 0;
 430                                         break;
 431                                 }
 432 #if CONFIG_COMPRESSED_PAYLOAD_NRV2B
 433                                 case CBFS_COMPRESS_NRV2B: {
 434                                         printk(BIOS_DEBUG, "using NRV2B\n");
 435                                         unsigned long unrv2b(u8 *src, u8 *dst, unsigned long *ilen_p);
 436                                         unsigned long tmp;
 437                                         len = unrv2b(src, dest, &tmp);
 438                                         break;
 439                                 }
 440 #endif
 441                                 case CBFS_COMPRESS_NONE: {
 442                                         printk(BIOS_DEBUG, "it's not compressed!\n");
 443                                         memcpy(dest, src, len);
 444                                         break;
 445                                 }
 446                                 default:
 447                                         printk(BIOS_INFO,  "CBFS:  Unknown compression type %d\n", ptr->compression);
 448                                         return -1;
 449                         }
 450                         end = dest + ptr->s_memsz;
 451                         middle = dest + len;
 452                         printk(BIOS_SPEW, "[ 0x%08lx, %08lx, 0x%08lx) <- %08lx\n",
 453                                 (unsigned long)dest,
 454                                 (unsigned long)middle,
 455                                 (unsigned long)end,
 456                                 (unsigned long)src);
 457
 458                         /* Zero the extra bytes between middle & end */
 459                         if (middle < end) {
 460                                 printk(BIOS_DEBUG, "Clearing Segment: addr: 0x%016lx memsz: 0x%016lx\n",
 461                                         (unsigned long)middle, (unsigned long)(end - middle));
 462
 463                                 /* Zero the extra bytes */
 464                                 memset(middle, 0, end - middle);
 465                         }
 466                         /* Copy the data that's outside the area that shadows coreboot_ram */
 467                         printk(BIOS_DEBUG, "dest %p, end %p, bouncebuffer %lx\n", dest, end, bounce_buffer);
 468                         if ((unsigned long)end > bounce_buffer) {
 469                                 if ((unsigned long)dest < bounce_buffer) {
 470                                         unsigned char *from = dest;
 471                                         unsigned char *to = (unsigned char*)(lb_start-(bounce_buffer-(unsigned long)dest));
 472                                         unsigned long amount = bounce_buffer-(unsigned long)dest;
 473                                         printk(BIOS_DEBUG, "move prefix around: from %p, to %p, amount: %lx\n", from, to, amount);
 474                                         memcpy(to, from, amount);
 475                                 }
 476                                 if ((unsigned long)end > bounce_buffer + (lb_end - lb_start)) {
 477                                         unsigned long from = bounce_buffer + (lb_end - lb_start);
 478                                         unsigned long to = lb_end;
 479                                         unsigned long amount = (unsigned long)end - from;
 480                                         printk(BIOS_DEBUG, "move suffix around: from %lx, to %lx, amount: %lx\n", from, to, amount);
 481                                         memcpy((char*)to, (char*)from, amount);
 482                                 }
 483                         }
 484                 }
 485         }
 486         return 1;
 487 }
 488
 489 static int selfboot(struct lb_memory *mem, struct cbfs_payload *payload)
 490 {
 491         u32 entry=0;
 492         struct segment head;
 493
 494         /* Preprocess the self segments */
 495         if (!build_self_segment_list(&head, mem, payload, &entry))
 496                 goto out;
 497
 498         /* Load the segments */
 499         if (!load_self_segments(&head, mem, payload))
 500                 goto out;
 501
 502         printk(BIOS_SPEW, "Loaded segments\n");
 503
 504         /* Reset to booting from this image as late as possible */
 505         boot_successful();
 506
 507         printk(BIOS_DEBUG, "Jumping to boot code at %x\n", entry);
 508         post_code(POST_ENTER_ELF_BOOT);
 509
 510         /* Jump to kernel */
 511         jmp_to_elf_entry((void*)entry, bounce_buffer, bounce_size);
 512         return 1;
 513
 514 out:
 515         return 0;
 516 }
 517
 518 void *cbfs_load_payload(struct lb_memory *lb_mem, const char *name)
 519 {
 520         struct cbfs_payload *payload;
 521
 522         payload = (struct cbfs_payload *)cbfs_find_file(name, CBFS_TYPE_PAYLOAD);
 523         if (payload == NULL)
 524                 return (void *) -1;
 525         printk(BIOS_DEBUG, "Got a payload\n");
 526
 527         selfboot(lb_mem, payload);
 528         printk(BIOS_EMERG, "SELFBOOT RETURNED!\n");
 529
 530         return (void *) -1;
 531 }
 532