src/lib/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 <cpu/cpu.h>
  24 #include <stdint.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <cbfs.h>
  28 #include <lib.h>
  29 #include <bootmem.h>
  30 #include <payload_loader.h>
  31
  32 /* from ramstage.ld: */
  33 extern unsigned char _ram_seg;
  34 extern unsigned char _eram_seg;
  35
  36 static const unsigned long lb_start = (unsigned long)&_ram_seg;
  37 static const unsigned long lb_end = (unsigned long)&_eram_seg;
  38
  39 struct segment {
  40         struct segment *next;
  41         struct segment *prev;
  42         unsigned long s_dstaddr;
  43         unsigned long s_srcaddr;
  44         unsigned long s_memsz;
  45         unsigned long s_filesz;
  46         int compression;
  47 };
  48
  49 /* The problem:
  50  * Static executables all want to share the same addresses
  51  * in memory because only a few addresses are reliably present on
  52  * a machine, and implementing general relocation is hard.
  53  *
  54  * The solution:
  55  * - Allocate a buffer the size of the coreboot image plus additional
  56  *   required space.
  57  * - Anything that would overwrite coreboot copy into the lower part of
  58  *   the buffer.
  59  * - After loading an ELF image copy coreboot to the top of the buffer.
  60  * - Then jump to the loaded image.
  61  *
  62  * Benefits:
  63  * - Nearly arbitrary standalone executables can be loaded.
  64  * - Coreboot is preserved, so it can be returned to.
  65  * - The implementation is still relatively simple,
  66  *   and much simpler than the general case implemented in kexec.
  67  */
  68
  69 static unsigned long bounce_size, bounce_buffer;
  70
  71 static void get_bounce_buffer(unsigned long req_size)
  72 {
  73         unsigned long lb_size;
  74         void *buffer;
  75
  76         /* When the ramstage is relocatable there is no need for a bounce
  77          * buffer. All payloads should not overlap the ramstage.
  78          */
  79         if (IS_ENABLED(CONFIG_RELOCATABLE_RAMSTAGE)) {
  80                 bounce_buffer = ~0UL;
  81                 bounce_size = 0;
  82                 return;
  83         }
  84
  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
  91         buffer = bootmem_allocate_buffer(lb_size);
  92
  93         printk(BIOS_SPEW, "Bounce Buffer at %p, %lu bytes\n", buffer, lb_size);
  94
  95         bounce_buffer = (uintptr_t)buffer;
  96         bounce_size = req_size;
  97 }
  98
  99 static int overlaps_coreboot(struct segment *seg)
 100 {
 101         unsigned long start, end;
 102         start = seg->s_dstaddr;
 103         end = start + seg->s_memsz;
 104         return !((end <= lb_start) || (start >= lb_end));
 105 }
 106
 107 static int relocate_segment(unsigned long buffer, struct segment *seg)
 108 {
 109         /* Modify all segments that want to load onto coreboot
 110          * to load onto the bounce buffer instead.
 111          */
 112         /* ret:  1 : A new segment is inserted before the seg.
 113          *       0 : A new segment is inserted after the seg, or no new one.
 114          */
 115         unsigned long start, middle, end, ret = 0;
 116
 117         printk(BIOS_SPEW, "lb: [0x%016lx, 0x%016lx)\n",
 118                 lb_start, lb_end);
 119
 120         /* I don't conflict with coreboot so get out of here */
 121         if (!overlaps_coreboot(seg))
 122                 return 0;
 123
 124         start = seg->s_dstaddr;
 125         middle = start + seg->s_filesz;
 126         end = start + seg->s_memsz;
 127
 128         printk(BIOS_SPEW, "segment: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 129                 start, middle, end);
 130
 131         if (seg->compression == CBFS_COMPRESS_NONE) {
 132                 /* Slice off a piece at the beginning
 133                  * that doesn't conflict with coreboot.
 134                  */
 135                 if (start < lb_start) {
 136                         struct segment *new;
 137                         unsigned long len = lb_start - start;
 138                         new = malloc(sizeof(*new));
 139                         *new = *seg;
 140                         new->s_memsz = len;
 141                         seg->s_memsz -= len;
 142                         seg->s_dstaddr += len;
 143                         seg->s_srcaddr += len;
 144                         if (seg->s_filesz > len) {
 145                                 new->s_filesz = len;
 146                                 seg->s_filesz -= len;
 147                         } else {
 148                                 seg->s_filesz = 0;
 149                         }
 150
 151                         /* Order by stream offset */
 152                         new->next = seg;
 153                         new->prev = seg->prev;
 154                         seg->prev->next = new;
 155                         seg->prev = new;
 156
 157                         /* compute the new value of start */
 158                         start = seg->s_dstaddr;
 159
 160                         printk(BIOS_SPEW, "   early: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 161                                 new->s_dstaddr,
 162                                 new->s_dstaddr + new->s_filesz,
 163                                 new->s_dstaddr + new->s_memsz);
 164
 165                         ret = 1;
 166                 }
 167
 168                 /* Slice off a piece at the end
 169                  * that doesn't conflict with coreboot
 170                  */
 171                 if (end > lb_end) {
 172                         unsigned long len = lb_end - start;
 173                         struct segment *new;
 174                         new = malloc(sizeof(*new));
 175                         *new = *seg;
 176                         seg->s_memsz = len;
 177                         new->s_memsz -= len;
 178                         new->s_dstaddr += len;
 179                         new->s_srcaddr += len;
 180                         if (seg->s_filesz > len) {
 181                                 seg->s_filesz = len;
 182                                 new->s_filesz -= len;
 183                         } else {
 184                                 new->s_filesz = 0;
 185                         }
 186                         /* Order by stream offset */
 187                         new->next = seg->next;
 188                         new->prev = seg;
 189                         seg->next->prev = new;
 190                         seg->next = new;
 191
 192                         printk(BIOS_SPEW, "   late: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 193                                 new->s_dstaddr,
 194                                 new->s_dstaddr + new->s_filesz,
 195                                 new->s_dstaddr + new->s_memsz);
 196                 }
 197         }
 198
 199         /* Now retarget this segment onto the bounce buffer */
 200         /* sort of explanation: the buffer is a 1:1 mapping to coreboot.
 201          * so you will make the dstaddr be this buffer, and it will get copied
 202          * later to where coreboot lives.
 203          */
 204         seg->s_dstaddr = buffer + (seg->s_dstaddr - lb_start);
 205
 206         printk(BIOS_SPEW, " bounce: [0x%016lx, 0x%016lx, 0x%016lx)\n",
 207                 seg->s_dstaddr,
 208                 seg->s_dstaddr + seg->s_filesz,
 209                 seg->s_dstaddr + seg->s_memsz);
 210
 211         return ret;
 212 }
 213
 214
 215 static int build_self_segment_list(
 216         struct segment *head,
 217         struct payload *payload, uintptr_t *entry)
 218 {
 219         struct segment *new;
 220         struct segment *ptr;
 221         struct cbfs_payload_segment *segment, *first_segment;
 222         struct cbfs_payload *cbfs_payload;
 223         cbfs_payload = payload->backing_store.data;
 224         memset(head, 0, sizeof(*head));
 225         head->next = head->prev = head;
 226         first_segment = segment = &cbfs_payload->segments;
 227
 228         while(1) {
 229                 printk(BIOS_DEBUG, "Loading segment from rom address 0x%p\n", segment);
 230                 switch(segment->type) {
 231                 case PAYLOAD_SEGMENT_PARAMS:
 232                         printk(BIOS_DEBUG, "  parameter section (skipped)\n");
 233                         segment++;
 234                         continue;
 235
 236                 case PAYLOAD_SEGMENT_CODE:
 237                 case PAYLOAD_SEGMENT_DATA:
 238                         printk(BIOS_DEBUG, "  %s (compression=%x)\n",
 239                                         segment->type == PAYLOAD_SEGMENT_CODE ?  "code" : "data",
 240                                         ntohl(segment->compression));
 241                         new = malloc(sizeof(*new));
 242                         new->s_dstaddr = ntohll(segment->load_addr);
 243                         new->s_memsz = ntohl(segment->mem_len);
 244                         new->compression = ntohl(segment->compression);
 245
 246                         new->s_srcaddr = (uintptr_t)
 247                                 ((unsigned char *)first_segment)
 248                                 + ntohl(segment->offset);
 249                         new->s_filesz = ntohl(segment->len);
 250                         printk(BIOS_DEBUG, "  New segment dstaddr 0x%lx memsize 0x%lx srcaddr 0x%lx filesize 0x%lx\n",
 251                                 new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
 252                         /* Clean up the values */
 253                         if (new->s_filesz > new->s_memsz)  {
 254                                 new->s_filesz = new->s_memsz;
 255                                 printk(BIOS_DEBUG,
 256                                        "  cleaned up filesize 0x%lx\n",
 257                                        new->s_filesz);
 258                         }
 259                         break;
 260
 261                 case PAYLOAD_SEGMENT_BSS:
 262                         printk(BIOS_DEBUG, "  BSS 0x%p (%d byte)\n", (void *)
 263                                         (intptr_t)ntohll(segment->load_addr),
 264                                         ntohl(segment->mem_len));
 265                         new = malloc(sizeof(*new));
 266                         new->s_filesz = 0;
 267                         new->s_srcaddr = (uintptr_t)
 268                                 ((unsigned char *)first_segment)
 269                                 + ntohl(segment->offset);
 270                         new->s_dstaddr = ntohll(segment->load_addr);
 271                         new->s_memsz = ntohl(segment->mem_len);
 272                         break;
 273
 274                 case PAYLOAD_SEGMENT_ENTRY:
 275                         printk(BIOS_DEBUG, "  Entry Point 0x%p\n",
 276                                (void *)(intptr_t)ntohll(segment->load_addr));
 277                         *entry =  ntohll(segment->load_addr);
 278                         /* Per definition, a payload always has the entry point
 279                          * as last segment. Thus, we use the occurrence of the
 280                          * entry point as break condition for the loop.
 281                          * Can we actually just look at the number of section?
 282                          */
 283                         return 1;
 284
 285                 default:
 286                         /* We found something that we don't know about. Throw
 287                          * hands into the sky and run away!
 288                          */
 289                         printk(BIOS_EMERG, "Bad segment type %x\n", segment->type);
 290                         return -1;
 291                 }
 292
 293                 /* We have found another CODE, DATA or BSS segment */
 294                 segment++;
 295
 296                 /* Find place where to insert our segment */
 297                 for(ptr = head->next; ptr != head; ptr = ptr->next) {
 298                         if (new->s_srcaddr < ntohll(segment->load_addr))
 299                                 break;
 300                 }
 301
 302                 /* Order by stream offset */
 303                 new->next = ptr;
 304                 new->prev = ptr->prev;
 305                 ptr->prev->next = new;
 306                 ptr->prev = new;
 307         }
 308
 309         return 1;
 310 }
 311
 312 static int load_self_segments(
 313         struct segment *head,
 314         struct payload *payload)
 315 {
 316         struct segment *ptr;
 317         const unsigned long one_meg = (1UL << 20);
 318         unsigned long bounce_high = lb_end;
 319
 320         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 321                 if (bootmem_region_targets_usable_ram(ptr->s_dstaddr,
 322                                                         ptr->s_memsz))
 323                         continue;
 324
 325                 if (ptr->s_dstaddr < one_meg &&
 326                     (ptr->s_dstaddr + ptr->s_memsz) <= one_meg) {
 327                         printk(BIOS_DEBUG,
 328                                 "Payload being loaded below 1MiB "
 329                                 "without region being marked as RAM usable.\n");
 330                         continue;
 331                 }
 332
 333                 /* Payload segment not targeting RAM. */
 334                 printk(BIOS_ERR, "SELF Payload doesn't target RAM:\n");
 335                 printk(BIOS_ERR, "Failed Segment: 0x%lx, %lu bytes\n",
 336                         ptr->s_dstaddr, ptr->s_memsz);
 337                 bootmem_dump_ranges();
 338                 return 0;
 339         }
 340
 341         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 342                 /*
 343                  * Add segments to bootmem memory map before a bounce buffer is
 344                  * allocated so that there aren't conflicts with the actual
 345                  * payload.
 346                  */
 347                 bootmem_add_range(ptr->s_dstaddr, ptr->s_memsz,
 348                                         LB_MEM_UNUSABLE);
 349
 350                 if (!overlaps_coreboot(ptr))
 351                         continue;
 352                 if (ptr->s_dstaddr + ptr->s_memsz > bounce_high)
 353                         bounce_high = ptr->s_dstaddr + ptr->s_memsz;
 354         }
 355         get_bounce_buffer(bounce_high - lb_start);
 356         if (!bounce_buffer) {
 357                 printk(BIOS_ERR, "Could not find a bounce buffer...\n");
 358                 return 0;
 359         }
 360
 361         /* Update the payload's bounce buffer data used when loading. */
 362         payload->bounce.data = (void *)(uintptr_t)bounce_buffer;
 363         payload->bounce.size = bounce_size;
 364
 365         for(ptr = head->next; ptr != head; ptr = ptr->next) {
 366                 unsigned char *dest, *src;
 367                 printk(BIOS_DEBUG, "Loading Segment: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
 368                         ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);
 369
 370                 /* Modify the segment to load onto the bounce_buffer if necessary.
 371                  */
 372                 if (relocate_segment(bounce_buffer, ptr)) {
 373                         ptr = (ptr->prev)->prev;
 374                         continue;
 375                 }
 376
 377                 printk(BIOS_DEBUG, "Post relocation: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
 378                         ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);
 379
 380                 /* Compute the boundaries of the segment */
 381                 dest = (unsigned char *)(ptr->s_dstaddr);
 382                 src = (unsigned char *)(ptr->s_srcaddr);
 383
 384                 /* Copy data from the initial buffer */
 385                 if (ptr->s_filesz) {
 386                         unsigned char *middle, *end;
 387                         size_t len;
 388                         len = ptr->s_filesz;
 389                         switch(ptr->compression) {
 390                                 case CBFS_COMPRESS_LZMA: {
 391                                         printk(BIOS_DEBUG, "using LZMA\n");
 392                                         len = ulzma(src, dest);
 393                                         if (!len) /* Decompression Error. */
 394                                                 return 0;
 395                                         break;
 396                                 }
 397                                 case CBFS_COMPRESS_NONE: {
 398                                         printk(BIOS_DEBUG, "it's not compressed!\n");
 399                                         memcpy(dest, src, len);
 400                                         break;
 401                                 }
 402                                 default:
 403                                         printk(BIOS_INFO,  "CBFS:  Unknown compression type %d\n", ptr->compression);
 404                                         return -1;
 405                         }
 406                         end = dest + ptr->s_memsz;
 407                         middle = dest + len;
 408                         printk(BIOS_SPEW, "[ 0x%08lx, %08lx, 0x%08lx) <- %08lx\n",
 409                                 (unsigned long)dest,
 410                                 (unsigned long)middle,
 411                                 (unsigned long)end,
 412                                 (unsigned long)src);
 413
 414                         /* Zero the extra bytes between middle & end */
 415                         if (middle < end) {
 416                                 printk(BIOS_DEBUG, "Clearing Segment: addr: 0x%016lx memsz: 0x%016lx\n",
 417                                         (unsigned long)middle, (unsigned long)(end - middle));
 418
 419                                 /* Zero the extra bytes */
 420                                 memset(middle, 0, end - middle);
 421                         }
 422                         /* Copy the data that's outside the area that shadows ramstage */
 423                         printk(BIOS_DEBUG, "dest %p, end %p, bouncebuffer %lx\n", dest, end, bounce_buffer);
 424                         if ((unsigned long)end > bounce_buffer) {
 425                                 if ((unsigned long)dest < bounce_buffer) {
 426                                         unsigned char *from = dest;
 427                                         unsigned char *to = (unsigned char*)(lb_start-(bounce_buffer-(unsigned long)dest));
 428                                         unsigned long amount = bounce_buffer-(unsigned long)dest;
 429                                         printk(BIOS_DEBUG, "move prefix around: from %p, to %p, amount: %lx\n", from, to, amount);
 430                                         memcpy(to, from, amount);
 431                                 }
 432                                 if ((unsigned long)end > bounce_buffer + (lb_end - lb_start)) {
 433                                         unsigned long from = bounce_buffer + (lb_end - lb_start);
 434                                         unsigned long to = lb_end;
 435                                         unsigned long amount = (unsigned long)end - from;
 436                                         printk(BIOS_DEBUG, "move suffix around: from %lx, to %lx, amount: %lx\n", from, to, amount);
 437                                         memcpy((char*)to, (char*)from, amount);
 438                                 }
 439                         }
 440                 }
 441         }
 442         return 1;
 443 }
 444
 445 void *selfload(struct payload *payload)
 446 {
 447         uintptr_t entry = 0;
 448         struct segment head;
 449
 450         /* Preprocess the self segments */
 451         if (!build_self_segment_list(&head, payload, &entry))
 452                 goto out;
 453
 454         /* Load the segments */
 455         if (!load_self_segments(&head, payload))
 456                 goto out;
 457
 458         printk(BIOS_SPEW, "Loaded segments\n");
 459
 460         return (void *)entry;
 461
 462 out:
 463         return NULL;
 464 }