kernel/power/swsusp.c

   1 /*
   2  * linux/kernel/power/swsusp.c
   3  *
   4  * This file is to realize architecture-independent
   5  * machine suspend feature using pretty near only high-level routines
   6  *
   7  * Copyright (C) 1998-2001 Gabor Kuti <seasons@fornax.hu>
   8  * Copyright (C) 1998,2001-2004 Pavel Machek <pavel@suse.cz>
   9  *
  10  * This file is released under the GPLv2.
  11  *
  12  * I'd like to thank the following people for their work:
  13  *
  14  * Pavel Machek <pavel@ucw.cz>:
  15  * Modifications, defectiveness pointing, being with me at the very beginning,
  16  * suspend to swap space, stop all tasks. Port to 2.4.18-ac and 2.5.17.
  17  *
  18  * Steve Doddi <dirk@loth.demon.co.uk>:
  19  * Support the possibility of hardware state restoring.
  20  *
  21  * Raph <grey.havens@earthling.net>:
  22  * Support for preserving states of network devices and virtual console
  23  * (including X and svgatextmode)
  24  *
  25  * Kurt Garloff <garloff@suse.de>:
  26  * Straightened the critical function in order to prevent compilers from
  27  * playing tricks with local variables.
  28  *
  29  * Andreas Mohr <a.mohr@mailto.de>
  30  *
  31  * Alex Badea <vampire@go.ro>:
  32  * Fixed runaway init
  33  *
  34  * More state savers are welcome. Especially for the scsi layer...
  35  *
  36  * For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
  37  */
  38
  39 #include <linux/module.h>
  40 #include <linux/mm.h>
  41 #include <linux/suspend.h>
  42 #include <linux/smp_lock.h>
  43 #include <linux/file.h>
  44 #include <linux/utsname.h>
  45 #include <linux/version.h>
  46 #include <linux/delay.h>
  47 #include <linux/reboot.h>
  48 #include <linux/bitops.h>
  49 #include <linux/vt_kern.h>
  50 #include <linux/kbd_kern.h>
  51 #include <linux/keyboard.h>
  52 #include <linux/spinlock.h>
  53 #include <linux/genhd.h>
  54 #include <linux/kernel.h>
  55 #include <linux/major.h>
  56 #include <linux/swap.h>
  57 #include <linux/pm.h>
  58 #include <linux/device.h>
  59 #include <linux/buffer_head.h>
  60 #include <linux/swapops.h>
  61 #include <linux/bootmem.h>
  62 #include <linux/syscalls.h>
  63 #include <linux/console.h>
  64 #include <linux/highmem.h>
  65 #include <linux/bio.h>
  66
  67 #include <asm/uaccess.h>
  68 #include <asm/mmu_context.h>
  69 #include <asm/pgtable.h>
  70 #include <asm/tlbflush.h>
  71 #include <asm/io.h>
  72
  73 #include "power.h"
  74
  75 /* References to section boundaries */
  76 extern const void __nosave_begin, __nosave_end;
  77
  78 /* Variables to be preserved over suspend */
  79 static int nr_copy_pages_check;
  80
  81 extern char resume_file[];
  82
  83 /* Local variables that should not be affected by save */
  84 unsigned int nr_copy_pages __nosavedata = 0;
  85
  86 /* Suspend pagedir is allocated before final copy, therefore it
  87    must be freed after resume
  88
  89    Warning: this is evil. There are actually two pagedirs at time of
  90    resume. One is "pagedir_save", which is empty frame allocated at
  91    time of suspend, that must be freed. Second is "pagedir_nosave",
  92    allocated at time of resume, that travels through memory not to
  93    collide with anything.
  94
  95    Warning: this is even more evil than it seems. Pagedirs this file
  96    talks about are completely different from page directories used by
  97    MMU hardware.
  98  */
  99 suspend_pagedir_t *pagedir_nosave __nosavedata = NULL;
 100 static suspend_pagedir_t *pagedir_save;
 101
 102 #define SWSUSP_SIG      "S1SUSPEND"
 103
 104 static struct swsusp_header {
 105         char reserved[PAGE_SIZE - 20 - sizeof(swp_entry_t)];
 106         swp_entry_t swsusp_info;
 107         char    orig_sig[10];
 108         char    sig[10];
 109 } __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
 110
 111 static struct swsusp_info swsusp_info;
 112
 113 /*
 114  * XXX: We try to keep some more pages free so that I/O operations succeed
 115  * without paging. Might this be more?
 116  */
 117 #define PAGES_FOR_IO    512
 118
 119 /*
 120  * Saving part...
 121  */
 122
 123 /* We memorize in swapfile_used what swap devices are used for suspension */
 124 #define SWAPFILE_UNUSED    0
 125 #define SWAPFILE_SUSPEND   1    /* This is the suspending device */
 126 #define SWAPFILE_IGNORED   2    /* Those are other swap devices ignored for suspension */
 127
 128 static unsigned short swapfile_used[MAX_SWAPFILES];
 129 static unsigned short root_swap;
 130
 131 static int mark_swapfiles(swp_entry_t prev)
 132 {
 133         int error;
 134
 135         rw_swap_page_sync(READ,
 136                           swp_entry(root_swap, 0),
 137                           virt_to_page((unsigned long)&swsusp_header));
 138         if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
 139             !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
 140                 memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
 141                 memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
 142                 swsusp_header.swsusp_info = prev;
 143                 error = rw_swap_page_sync(WRITE,
 144                                           swp_entry(root_swap, 0),
 145                                           virt_to_page((unsigned long)
 146                                                        &swsusp_header));
 147         } else {
 148                 pr_debug("swsusp: Partition is not swap space.\n");
 149                 error = -ENODEV;
 150         }
 151         return error;
 152 }
 153
 154 /*
 155  * Check whether the swap device is the specified resume
 156  * device, irrespective of whether they are specified by
 157  * identical names.
 158  *
 159  * (Thus, device inode aliasing is allowed.  You can say /dev/hda4
 160  * instead of /dev/ide/host0/bus0/target0/lun0/part4 [if using devfs]
 161  * and they'll be considered the same device.  This is *necessary* for
 162  * devfs, since the resume code can only recognize the form /dev/hda4,
 163  * but the suspend code would see the long name.)
 164  */
 165 static int is_resume_device(const struct swap_info_struct *swap_info)
 166 {
 167         struct file *file = swap_info->swap_file;
 168         struct inode *inode = file->f_dentry->d_inode;
 169
 170         return S_ISBLK(inode->i_mode) &&
 171                 swsusp_resume_device == MKDEV(imajor(inode), iminor(inode));
 172 }
 173
 174 static int swsusp_swap_check(void) /* This is called before saving image */
 175 {
 176         int i, len;
 177
 178         len=strlen(resume_file);
 179         root_swap = 0xFFFF;
 180
 181         swap_list_lock();
 182         for(i=0; i<MAX_SWAPFILES; i++) {
 183                 if (swap_info[i].flags == 0) {
 184                         swapfile_used[i]=SWAPFILE_UNUSED;
 185                 } else {
 186                         if(!len) {
 187                                 printk(KERN_WARNING "resume= option should be used to set suspend device" );
 188                                 if(root_swap == 0xFFFF) {
 189                                         swapfile_used[i] = SWAPFILE_SUSPEND;
 190                                         root_swap = i;
 191                                 } else
 192                                         swapfile_used[i] = SWAPFILE_IGNORED;
 193                         } else {
 194                                 /* we ignore all swap devices that are not the resume_file */
 195                                 if (is_resume_device(&swap_info[i])) {
 196                                         swapfile_used[i] = SWAPFILE_SUSPEND;
 197                                         root_swap = i;
 198                                 } else {
 199                                         swapfile_used[i] = SWAPFILE_IGNORED;
 200                                 }
 201                         }
 202                 }
 203         }
 204         swap_list_unlock();
 205         return (root_swap != 0xffff) ? 0 : -ENODEV;
 206 }
 207
 208 /**
 209  * This is called after saving image so modification
 210  * will be lost after resume... and that's what we want.
 211  * we make the device unusable. A new call to
 212  * lock_swapdevices can unlock the devices.
 213  */
 214 static void lock_swapdevices(void)
 215 {
 216         int i;
 217
 218         swap_list_lock();
 219         for(i = 0; i< MAX_SWAPFILES; i++)
 220                 if(swapfile_used[i] == SWAPFILE_IGNORED) {
 221                         swap_info[i].flags ^= 0xFF;
 222                 }
 223         swap_list_unlock();
 224 }
 225
 226 /**
 227  *      write_swap_page - Write one page to a fresh swap location.
 228  *      @addr:  Address we're writing.
 229  *      @loc:   Place to store the entry we used.
 230  *
 231  *      Allocate a new swap entry and 'sync' it. Note we discard -EIO
 232  *      errors. That is an artifact left over from swsusp. It did not
 233  *      check the return of rw_swap_page_sync() at all, since most pages
 234  *      written back to swap would return -EIO.
 235  *      This is a partial improvement, since we will at least return other
 236  *      errors, though we need to eventually fix the damn code.
 237  */
 238 static int write_page(unsigned long addr, swp_entry_t * loc)
 239 {
 240         swp_entry_t entry;
 241         int error = 0;
 242
 243         entry = get_swap_page();
 244         if (swp_offset(entry) &&
 245             swapfile_used[swp_type(entry)] == SWAPFILE_SUSPEND) {
 246                 error = rw_swap_page_sync(WRITE, entry,
 247                                           virt_to_page(addr));
 248                 if (error == -EIO)
 249                         error = 0;
 250                 if (!error)
 251                         *loc = entry;
 252         } else
 253                 error = -ENOSPC;
 254         return error;
 255 }
 256
 257 /**
 258  *      data_free - Free the swap entries used by the saved image.
 259  *
 260  *      Walk the list of used swap entries and free each one.
 261  *      This is only used for cleanup when suspend fails.
 262  */
 263 static void data_free(void)
 264 {
 265         swp_entry_t entry;
 266         int i;
 267
 268         for (i = 0; i < nr_copy_pages; i++) {
 269                 entry = (pagedir_nosave + i)->swap_address;
 270                 if (entry.val)
 271                         swap_free(entry);
 272                 else
 273                         break;
 274                 (pagedir_nosave + i)->swap_address = (swp_entry_t){0};
 275         }
 276 }
 277
 278 /**
 279  *      data_write - Write saved image to swap.
 280  *
 281  *      Walk the list of pages in the image and sync each one to swap.
 282  */
 283 static int data_write(void)
 284 {
 285         int error = 0, i = 0;
 286         unsigned int mod = nr_copy_pages / 100;
 287         struct pbe *p;
 288
 289         if (!mod)
 290                 mod = 1;
 291
 292         printk( "Writing data to swap (%d pages)...     ", nr_copy_pages );
 293         for_each_pbe(p, pagedir_nosave) {
 294                 if (!(i%mod))
 295                         printk( "\b\b\b\b%3d%%", i / mod );
 296                 if ((error = write_page(p->address, &(p->swap_address))))
 297                         return error;
 298                 i++;
 299         }
 300         printk("\b\b\b\bdone\n");
 301         return error;
 302 }
 303
 304 static void dump_info(void)
 305 {
 306         pr_debug(" swsusp: Version: %u\n",swsusp_info.version_code);
 307         pr_debug(" swsusp: Num Pages: %ld\n",swsusp_info.num_physpages);
 308         pr_debug(" swsusp: UTS Sys: %s\n",swsusp_info.uts.sysname);
 309         pr_debug(" swsusp: UTS Node: %s\n",swsusp_info.uts.nodename);
 310         pr_debug(" swsusp: UTS Release: %s\n",swsusp_info.uts.release);
 311         pr_debug(" swsusp: UTS Version: %s\n",swsusp_info.uts.version);
 312         pr_debug(" swsusp: UTS Machine: %s\n",swsusp_info.uts.machine);
 313         pr_debug(" swsusp: UTS Domain: %s\n",swsusp_info.uts.domainname);
 314         pr_debug(" swsusp: CPUs: %d\n",swsusp_info.cpus);
 315         pr_debug(" swsusp: Image: %ld Pages\n",swsusp_info.image_pages);
 316         pr_debug(" swsusp: Pagedir: %ld Pages\n",swsusp_info.pagedir_pages);
 317 }
 318
 319 static void init_header(void)
 320 {
 321         memset(&swsusp_info, 0, sizeof(swsusp_info));
 322         swsusp_info.version_code = LINUX_VERSION_CODE;
 323         swsusp_info.num_physpages = num_physpages;
 324         memcpy(&swsusp_info.uts, &system_utsname, sizeof(system_utsname));
 325
 326         swsusp_info.suspend_pagedir = pagedir_nosave;
 327         swsusp_info.cpus = num_online_cpus();
 328         swsusp_info.image_pages = nr_copy_pages;
 329 }
 330
 331 static int close_swap(void)
 332 {
 333         swp_entry_t entry;
 334         int error;
 335
 336         dump_info();
 337         error = write_page((unsigned long)&swsusp_info, &entry);
 338         if (!error) {
 339                 printk( "S" );
 340                 error = mark_swapfiles(entry);
 341                 printk( "|\n" );
 342         }
 343         return error;
 344 }
 345
 346 /**
 347  *      free_pagedir_entries - Free pages used by the page directory.
 348  *
 349  *      This is used during suspend for error recovery.
 350  */
 351
 352 static void free_pagedir_entries(void)
 353 {
 354         int i;
 355
 356         for (i = 0; i < swsusp_info.pagedir_pages; i++)
 357                 swap_free(swsusp_info.pagedir[i]);
 358 }
 359
 360
 361 /**
 362  *      write_pagedir - Write the array of pages holding the page directory.
 363  *      @last:  Last swap entry we write (needed for header).
 364  */
 365
 366 static int write_pagedir(void)
 367 {
 368         int error = 0;
 369         unsigned n = 0;
 370         struct pbe * pbe;
 371
 372         printk( "Writing pagedir...");
 373         for_each_pb_page(pbe, pagedir_nosave) {
 374                 if ((error = write_page((unsigned long)pbe, &swsusp_info.pagedir[n++])))
 375                         return error;
 376         }
 377
 378         swsusp_info.pagedir_pages = n;
 379         printk("done (%u pages)\n", n);
 380         return error;
 381 }
 382
 383 /**
 384  *      write_suspend_image - Write entire image and metadata.
 385  *
 386  */
 387
 388 static int write_suspend_image(void)
 389 {
 390         int error;
 391
 392         init_header();
 393         if ((error = data_write()))
 394                 goto FreeData;
 395
 396         if ((error = write_pagedir()))
 397                 goto FreePagedir;
 398
 399         if ((error = close_swap()))
 400                 goto FreePagedir;
 401  Done:
 402         return error;
 403  FreePagedir:
 404         free_pagedir_entries();
 405  FreeData:
 406         data_free();
 407         goto Done;
 408 }
 409
 410
 411 #ifdef CONFIG_HIGHMEM
 412 struct highmem_page {
 413         char *data;
 414         struct page *page;
 415         struct highmem_page *next;
 416 };
 417
 418 static struct highmem_page *highmem_copy;
 419
 420 static int save_highmem_zone(struct zone *zone)
 421 {
 422         unsigned long zone_pfn;
 423         mark_free_pages(zone);
 424         for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
 425                 struct page *page;
 426                 struct highmem_page *save;
 427                 void *kaddr;
 428                 unsigned long pfn = zone_pfn + zone->zone_start_pfn;
 429
 430                 if (!(pfn%1000))
 431                         printk(".");
 432                 if (!pfn_valid(pfn))
 433                         continue;
 434                 page = pfn_to_page(pfn);
 435                 /*
 436                  * This condition results from rvmalloc() sans vmalloc_32()
 437                  * and architectural memory reservations. This should be
 438                  * corrected eventually when the cases giving rise to this
 439                  * are better understood.
 440                  */
 441                 if (PageReserved(page)) {
 442                         printk("highmem reserved page?!\n");
 443                         continue;
 444                 }
 445                 BUG_ON(PageNosave(page));
 446                 if (PageNosaveFree(page))
 447                         continue;
 448                 save = kmalloc(sizeof(struct highmem_page), GFP_ATOMIC);
 449                 if (!save)
 450                         return -ENOMEM;
 451                 save->next = highmem_copy;
 452                 save->page = page;
 453                 save->data = (void *) get_zeroed_page(GFP_ATOMIC);
 454                 if (!save->data) {
 455                         kfree(save);
 456                         return -ENOMEM;
 457                 }
 458                 kaddr = kmap_atomic(page, KM_USER0);
 459                 memcpy(save->data, kaddr, PAGE_SIZE);
 460                 kunmap_atomic(kaddr, KM_USER0);
 461                 highmem_copy = save;
 462         }
 463         return 0;
 464 }
 465 #endif /* CONFIG_HIGHMEM */
 466
 467
 468 static int save_highmem(void)
 469 {
 470 #ifdef CONFIG_HIGHMEM
 471         struct zone *zone;
 472         int res = 0;
 473
 474         pr_debug("swsusp: Saving Highmem\n");
 475         for_each_zone(zone) {
 476                 if (is_highmem(zone))
 477                         res = save_highmem_zone(zone);
 478                 if (res)
 479                         return res;
 480         }
 481 #endif
 482         return 0;
 483 }
 484
 485 static int restore_highmem(void)
 486 {
 487 #ifdef CONFIG_HIGHMEM
 488         printk("swsusp: Restoring Highmem\n");
 489         while (highmem_copy) {
 490                 struct highmem_page *save = highmem_copy;
 491                 void *kaddr;
 492                 highmem_copy = save->next;
 493
 494                 kaddr = kmap_atomic(save->page, KM_USER0);
 495                 memcpy(kaddr, save->data, PAGE_SIZE);
 496                 kunmap_atomic(kaddr, KM_USER0);
 497                 free_page((long) save->data);
 498                 kfree(save);
 499         }
 500 #endif
 501         return 0;
 502 }
 503
 504
 505 static int pfn_is_nosave(unsigned long pfn)
 506 {
 507         unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
 508         unsigned long nosave_end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
 509         return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
 510 }
 511
 512 /**
 513  *      saveable - Determine whether a page should be cloned or not.
 514  *      @pfn:   The page
 515  *
 516  *      We save a page if it's Reserved, and not in the range of pages
 517  *      statically defined as 'unsaveable', or if it isn't reserved, and
 518  *      isn't part of a free chunk of pages.
 519  */
 520
 521 static int saveable(struct zone * zone, unsigned long * zone_pfn)
 522 {
 523         unsigned long pfn = *zone_pfn + zone->zone_start_pfn;
 524         struct page * page;
 525
 526         if (!pfn_valid(pfn))
 527                 return 0;
 528
 529         page = pfn_to_page(pfn);
 530         BUG_ON(PageReserved(page) && PageNosave(page));
 531         if (PageNosave(page))
 532                 return 0;
 533         if (PageReserved(page) && pfn_is_nosave(pfn)) {
 534                 pr_debug("[nosave pfn 0x%lx]", pfn);
 535                 return 0;
 536         }
 537         if (PageNosaveFree(page))
 538                 return 0;
 539
 540         return 1;
 541 }
 542
 543 static void count_data_pages(void)
 544 {
 545         struct zone *zone;
 546         unsigned long zone_pfn;
 547
 548         nr_copy_pages = 0;
 549
 550         for_each_zone(zone) {
 551                 if (is_highmem(zone))
 552                         continue;
 553                 mark_free_pages(zone);
 554                 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
 555                         nr_copy_pages += saveable(zone, &zone_pfn);
 556         }
 557 }
 558
 559
 560 static void copy_data_pages(void)
 561 {
 562         struct zone *zone;
 563         unsigned long zone_pfn;
 564         struct pbe * pbe = pagedir_nosave;
 565
 566         pr_debug("copy_data_pages(): pages to copy: %d\n", nr_copy_pages);
 567         for_each_zone(zone) {
 568                 if (is_highmem(zone))
 569                         continue;
 570                 mark_free_pages(zone);
 571                 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
 572                         if (saveable(zone, &zone_pfn)) {
 573                                 struct page * page;
 574                                 page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
 575                                 BUG_ON(!pbe);
 576                                 pbe->orig_address = (long) page_address(page);
 577                                 /* copy_page is not usable for copying task structs. */
 578                                 memcpy((void *)pbe->address, (void *)pbe->orig_address, PAGE_SIZE);
 579                                 pbe = pbe->next;
 580                         }
 581                 }
 582         }
 583         BUG_ON(pbe);
 584 }
 585
 586
 587 /**
 588  *      calc_nr - Determine the number of pages needed for a pbe list.
 589  */
 590
 591 static int calc_nr(int nr_copy)
 592 {
 593         int extra = 0;
 594         int mod = !!(nr_copy % PBES_PER_PAGE);
 595         int diff = (nr_copy / PBES_PER_PAGE) + mod;
 596
 597         do {
 598                 extra += diff;
 599                 nr_copy += diff;
 600                 mod = !!(nr_copy % PBES_PER_PAGE);
 601                 diff = (nr_copy / PBES_PER_PAGE) + mod - extra;
 602         } while (diff > 0);
 603
 604         return nr_copy;
 605 }
 606
 607 /**
 608  *      free_pagedir - free pages allocated with alloc_pagedir()
 609  */
 610
 611 static inline void free_pagedir(struct pbe *pblist)
 612 {
 613         struct pbe *pbe;
 614
 615         while (pblist) {
 616                 pbe = (pblist + PB_PAGE_SKIP)->next;
 617                 free_page((unsigned long)pblist);
 618                 pblist = pbe;
 619         }
 620 }
 621
 622 /**
 623  *      fill_pb_page - Create a list of PBEs on a given memory page
 624  */
 625
 626 static inline void fill_pb_page(struct pbe *pbpage)
 627 {
 628         struct pbe *p;
 629
 630         p = pbpage;
 631         pbpage += PB_PAGE_SKIP;
 632         do
 633                 p->next = p + 1;
 634         while (++p < pbpage);
 635 }
 636
 637 /**
 638  *      create_pbe_list - Create a list of PBEs on top of a given chain
 639  *      of memory pages allocated with alloc_pagedir()
 640  */
 641
 642 static void create_pbe_list(struct pbe *pblist, unsigned nr_pages)
 643 {
 644         struct pbe *pbpage, *p;
 645         unsigned num = PBES_PER_PAGE;
 646
 647         for_each_pb_page (pbpage, pblist) {
 648                 if (num >= nr_pages)
 649                         break;
 650
 651                 fill_pb_page(pbpage);
 652                 num += PBES_PER_PAGE;
 653         }
 654         if (pbpage) {
 655                 for (num -= PBES_PER_PAGE - 1, p = pbpage; num < nr_pages; p++, num++)
 656                         p->next = p + 1;
 657                 p->next = NULL;
 658         }
 659         pr_debug("create_pbe_list(): initialized %d PBEs\n", num);
 660 }
 661
 662 /**
 663  *      alloc_pagedir - Allocate the page directory.
 664  *
 665  *      First, determine exactly how many pages we need and
 666  *      allocate them.
 667  *
 668  *      We arrange the pages in a chain: each page is an array of PBES_PER_PAGE
 669  *      struct pbe elements (pbes) and the last element in the page points
 670  *      to the next page.
 671  *
 672  *      On each page we set up a list of struct_pbe elements.
 673  */
 674
 675 static struct pbe * alloc_pagedir(unsigned nr_pages)
 676 {
 677         unsigned num;
 678         struct pbe *pblist, *pbe;
 679
 680         if (!nr_pages)
 681                 return NULL;
 682
 683         pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages);
 684         pblist = (struct pbe *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
 685         for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
 686                         pbe = pbe->next, num += PBES_PER_PAGE) {
 687                 pbe += PB_PAGE_SKIP;
 688                 pbe->next = (struct pbe *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
 689         }
 690         if (!pbe) { /* get_zeroed_page() failed */
 691                 free_pagedir(pblist);
 692                 pblist = NULL;
 693         }
 694         return pblist;
 695 }
 696
 697 /**
 698  *      free_image_pages - Free pages allocated for snapshot
 699  */
 700
 701 static void free_image_pages(void)
 702 {
 703         struct pbe * p;
 704
 705         for_each_pbe(p, pagedir_save) {
 706                 if (p->address) {
 707                         ClearPageNosave(virt_to_page(p->address));
 708                         free_page(p->address);
 709                         p->address = 0;
 710                 }
 711         }
 712 }
 713
 714 /**
 715  *      alloc_image_pages - Allocate pages for the snapshot.
 716  */
 717
 718 static int alloc_image_pages(void)
 719 {
 720         struct pbe * p;
 721
 722         for_each_pbe(p, pagedir_save) {
 723                 p->address = get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
 724                 if (!p->address)
 725                         return -ENOMEM;
 726                 SetPageNosave(virt_to_page(p->address));
 727         }
 728         return 0;
 729 }
 730
 731 void swsusp_free(void)
 732 {
 733         BUG_ON(PageNosave(virt_to_page(pagedir_save)));
 734         BUG_ON(PageNosaveFree(virt_to_page(pagedir_save)));
 735         free_image_pages();
 736         free_pagedir(pagedir_save);
 737 }
 738
 739
 740 /**
 741  *      enough_free_mem - Make sure we enough free memory to snapshot.
 742  *
 743  *      Returns TRUE or FALSE after checking the number of available
 744  *      free pages.
 745  */
 746
 747 static int enough_free_mem(void)
 748 {
 749         if (nr_free_pages() < (nr_copy_pages + PAGES_FOR_IO)) {
 750                 pr_debug("swsusp: Not enough free pages: Have %d\n",
 751                          nr_free_pages());
 752                 return 0;
 753         }
 754         return 1;
 755 }
 756
 757
 758 /**
 759  *      enough_swap - Make sure we have enough swap to save the image.
 760  *
 761  *      Returns TRUE or FALSE after checking the total amount of swap
 762  *      space avaiable.
 763  *
 764  *      FIXME: si_swapinfo(&i) returns all swap devices information.
 765  *      We should only consider resume_device.
 766  */
 767
 768 static int enough_swap(void)
 769 {
 770         struct sysinfo i;
 771
 772         si_swapinfo(&i);
 773         if (i.freeswap < (nr_copy_pages + PAGES_FOR_IO))  {
 774                 pr_debug("swsusp: Not enough swap. Need %ld\n",i.freeswap);
 775                 return 0;
 776         }
 777         return 1;
 778 }
 779
 780 static int swsusp_alloc(void)
 781 {
 782         int error;
 783
 784         pr_debug("suspend: (pages needed: %d + %d free: %d)\n",
 785                  nr_copy_pages, PAGES_FOR_IO, nr_free_pages());
 786
 787         pagedir_nosave = NULL;
 788         if (!enough_free_mem())
 789                 return -ENOMEM;
 790
 791         if (!enough_swap())
 792                 return -ENOSPC;
 793
 794         nr_copy_pages = calc_nr(nr_copy_pages);
 795
 796         if (!(pagedir_save = alloc_pagedir(nr_copy_pages))) {
 797                 printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
 798                 return -ENOMEM;
 799         }
 800         create_pbe_list(pagedir_save, nr_copy_pages);
 801         pagedir_nosave = pagedir_save;
 802         if ((error = alloc_image_pages())) {
 803                 printk(KERN_ERR "suspend: Allocating image pages failed.\n");
 804                 swsusp_free();
 805                 return error;
 806         }
 807
 808         nr_copy_pages_check = nr_copy_pages;
 809         return 0;
 810 }
 811
 812 static int suspend_prepare_image(void)
 813 {
 814         int error;
 815
 816         pr_debug("swsusp: critical section: \n");
 817         if (save_highmem()) {
 818                 printk(KERN_CRIT "Suspend machine: Not enough free pages for highmem\n");
 819                 restore_highmem();
 820                 return -ENOMEM;
 821         }
 822
 823         drain_local_pages();
 824         count_data_pages();
 825         printk("swsusp: Need to copy %u pages\n", nr_copy_pages);
 826
 827         error = swsusp_alloc();
 828         if (error)
 829                 return error;
 830
 831         /* During allocating of suspend pagedir, new cold pages may appear.
 832          * Kill them.
 833          */
 834         drain_local_pages();
 835         copy_data_pages();
 836
 837         /*
 838          * End of critical section. From now on, we can write to memory,
 839          * but we should not touch disk. This specially means we must _not_
 840          * touch swap space! Except we must write out our image of course.
 841          */
 842
 843         printk("swsusp: critical section/: done (%d pages copied)\n", nr_copy_pages );
 844         return 0;
 845 }
 846
 847
 848 /* It is important _NOT_ to umount filesystems at this point. We want
 849  * them synced (in case something goes wrong) but we DO not want to mark
 850  * filesystem clean: it is not. (And it does not matter, if we resume
 851  * correctly, we'll mark system clean, anyway.)
 852  */
 853 int swsusp_write(void)
 854 {
 855         int error;
 856         device_resume();
 857         lock_swapdevices();
 858         error = write_suspend_image();
 859         /* This will unlock ignored swap devices since writing is finished */
 860         lock_swapdevices();
 861         return error;
 862
 863 }
 864
 865
 866 extern asmlinkage int swsusp_arch_suspend(void);
 867 extern asmlinkage int swsusp_arch_resume(void);
 868
 869
 870 asmlinkage int swsusp_save(void)
 871 {
 872         int error = 0;
 873
 874         if ((error = swsusp_swap_check())) {
 875                 printk(KERN_ERR "swsusp: FATAL: cannot find swap device, try "
 876                                 "swapon -a!\n");
 877                 return error;
 878         }
 879         return suspend_prepare_image();
 880 }
 881
 882 int swsusp_suspend(void)
 883 {
 884         int error;
 885         if ((error = arch_prepare_suspend()))
 886                 return error;
 887         local_irq_disable();
 888         /* At this point, device_suspend() has been called, but *not*
 889          * device_power_down(). We *must* device_power_down() now.
 890          * Otherwise, drivers for some devices (e.g. interrupt controllers)
 891          * become desynchronized with the actual state of the hardware
 892          * at resume time, and evil weirdness ensues.
 893          */
 894         if ((error = device_power_down(PMSG_FREEZE))) {
 895                 printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
 896                 local_irq_enable();
 897                 swsusp_free();
 898                 return error;
 899         }
 900         save_processor_state();
 901         if ((error = swsusp_arch_suspend()))
 902                 swsusp_free();
 903         /* Restore control flow magically appears here */
 904         restore_processor_state();
 905         BUG_ON (nr_copy_pages_check != nr_copy_pages);
 906         restore_highmem();
 907         device_power_up();
 908         local_irq_enable();
 909         return error;
 910 }
 911
 912 int swsusp_resume(void)
 913 {
 914         int error;
 915         local_irq_disable();
 916         if (device_power_down(PMSG_FREEZE))
 917                 printk(KERN_ERR "Some devices failed to power down, very bad\n");
 918         /* We'll ignore saved state, but this gets preempt count (etc) right */
 919         save_processor_state();
 920         error = swsusp_arch_resume();
 921         /* Code below is only ever reached in case of failure. Otherwise
 922          * execution continues at place where swsusp_arch_suspend was called
 923          */
 924         BUG_ON(!error);
 925         restore_processor_state();
 926         restore_highmem();
 927         device_power_up();
 928         local_irq_enable();
 929         return error;
 930 }
 931
 932 /* More restore stuff */
 933
 934 /*
 935  * Returns true if given address/order collides with any orig_address
 936  */
 937 static int does_collide_order(unsigned long addr, int order)
 938 {
 939         int i;
 940
 941         for (i=0; i < (1<<order); i++)
 942                 if (!PageNosaveFree(virt_to_page(addr + i * PAGE_SIZE)))
 943                         return 1;
 944         return 0;
 945 }
 946
 947 /**
 948  *      On resume, for storing the PBE list and the image,
 949  *      we can only use memory pages that do not conflict with the pages
 950  *      which had been used before suspend.
 951  *
 952  *      We don't know which pages are usable until we allocate them.
 953  *
 954  *      Allocated but unusable (ie eaten) memory pages are linked together
 955  *      to create a list, so that we can free them easily
 956  *
 957  *      We could have used a type other than (void *)
 958  *      for this purpose, but ...
 959  */
 960 static void **eaten_memory = NULL;
 961
 962 static inline void eat_page(void *page)
 963 {
 964         void **c;
 965
 966         c = eaten_memory;
 967         eaten_memory = page;
 968         *eaten_memory = c;
 969 }
 970
 971 static unsigned long get_usable_page(unsigned gfp_mask)
 972 {
 973         unsigned long m;
 974
 975         m = get_zeroed_page(gfp_mask);
 976         while (does_collide_order(m, 0)) {
 977                 eat_page((void *)m);
 978                 m = get_zeroed_page(gfp_mask);
 979                 if (!m)
 980                         break;
 981         }
 982         return m;
 983 }
 984
 985 static void free_eaten_memory(void)
 986 {
 987         unsigned long m;
 988         void **c;
 989         int i = 0;
 990
 991         c = eaten_memory;
 992         while (c) {
 993                 m = (unsigned long)c;
 994                 c = *c;
 995                 free_page(m);
 996                 i++;
 997         }
 998         eaten_memory = NULL;
 999         pr_debug("swsusp: %d unused pages freed\n", i);
1000 }
1001
1002 /**
1003  *      check_pagedir - We ensure here that pages that the PBEs point to
1004  *      won't collide with pages where we're going to restore from the loaded
1005  *      pages later
1006  */
1007
1008 static int check_pagedir(struct pbe *pblist)
1009 {
1010         struct pbe *p;
1011
1012         /* This is necessary, so that we can free allocated pages
1013          * in case of failure
1014          */
1015         for_each_pbe (p, pblist)
1016                 p->address = 0UL;
1017
1018         for_each_pbe (p, pblist) {
1019                 p->address = get_usable_page(GFP_ATOMIC);
1020                 if (!p->address)
1021                         return -ENOMEM;
1022         }
1023         return 0;
1024 }
1025
1026 /**
1027  *      swsusp_pagedir_relocate - It is possible, that some memory pages
1028  *      occupied by the list of PBEs collide with pages where we're going to
1029  *      restore from the loaded pages later.  We relocate them here.
1030  */
1031
1032 static struct pbe * swsusp_pagedir_relocate(struct pbe *pblist)
1033 {
1034         struct zone *zone;
1035         unsigned long zone_pfn;
1036         struct pbe *pbpage, *tail, *p;
1037         void *m;
1038         int rel = 0, error = 0;
1039
1040         if (!pblist) /* a sanity check */
1041                 return NULL;
1042
1043         pr_debug("swsusp: Relocating pagedir (%lu pages to check)\n",
1044                         swsusp_info.pagedir_pages);
1045
1046         /* Set page flags */
1047
1048         for_each_zone(zone) {
1049                 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
1050                         SetPageNosaveFree(pfn_to_page(zone_pfn +
1051                                         zone->zone_start_pfn));
1052         }
1053
1054         /* Clear orig addresses */
1055
1056         for_each_pbe (p, pblist)
1057                 ClearPageNosaveFree(virt_to_page(p->orig_address));
1058
1059         tail = pblist + PB_PAGE_SKIP;
1060
1061         /* Relocate colliding pages */
1062
1063         for_each_pb_page (pbpage, pblist) {
1064                 if (does_collide_order((unsigned long)pbpage, 0)) {
1065                         m = (void *)get_usable_page(GFP_ATOMIC | __GFP_COLD);
1066                         if (!m) {
1067                                 error = -ENOMEM;
1068                                 break;
1069                         }
1070                         memcpy(m, (void *)pbpage, PAGE_SIZE);
1071                         if (pbpage == pblist)
1072                                 pblist = (struct pbe *)m;
1073                         else
1074                                 tail->next = (struct pbe *)m;
1075
1076                         eat_page((void *)pbpage);
1077                         pbpage = (struct pbe *)m;
1078
1079                         /* We have to link the PBEs again */
1080
1081                         for (p = pbpage; p < pbpage + PB_PAGE_SKIP; p++)
1082                                 if (p->next) /* needed to save the end */
1083                                         p->next = p + 1;
1084
1085                         rel++;
1086                 }
1087                 tail = pbpage + PB_PAGE_SKIP;
1088         }
1089
1090         if (error) {
1091                 printk("\nswsusp: Out of memory\n\n");
1092                 free_pagedir(pblist);
1093                 free_eaten_memory();
1094                 pblist = NULL;
1095         }
1096         else
1097                 printk("swsusp: Relocated %d pages\n", rel);
1098
1099         return pblist;
1100 }
1101
1102 /*
1103  *      Using bio to read from swap.
1104  *      This code requires a bit more work than just using buffer heads
1105  *      but, it is the recommended way for 2.5/2.6.
1106  *      The following are to signal the beginning and end of I/O. Bios
1107  *      finish asynchronously, while we want them to happen synchronously.
1108  *      A simple atomic_t, and a wait loop take care of this problem.
1109  */
1110
1111 static atomic_t io_done = ATOMIC_INIT(0);
1112
1113 static int end_io(struct bio * bio, unsigned int num, int err)
1114 {
1115         if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1116                 panic("I/O error reading memory image");
1117         atomic_set(&io_done, 0);
1118         return 0;
1119 }
1120
1121 static struct block_device * resume_bdev;
1122
1123 /**
1124  *      submit - submit BIO request.
1125  *      @rw:    READ or WRITE.
1126  *      @off    physical offset of page.
1127  *      @page:  page we're reading or writing.
1128  *
1129  *      Straight from the textbook - allocate and initialize the bio.
1130  *      If we're writing, make sure the page is marked as dirty.
1131  *      Then submit it and wait.
1132  */
1133
1134 static int submit(int rw, pgoff_t page_off, void * page)
1135 {
1136         int error = 0;
1137         struct bio * bio;
1138
1139         bio = bio_alloc(GFP_ATOMIC, 1);
1140         if (!bio)
1141                 return -ENOMEM;
1142         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
1143         bio_get(bio);
1144         bio->bi_bdev = resume_bdev;
1145         bio->bi_end_io = end_io;
1146
1147         if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) {
1148                 printk("swsusp: ERROR: adding page to bio at %ld\n",page_off);
1149                 error = -EFAULT;
1150                 goto Done;
1151         }
1152
1153         if (rw == WRITE)
1154                 bio_set_pages_dirty(bio);
1155
1156         atomic_set(&io_done, 1);
1157         submit_bio(rw | (1 << BIO_RW_SYNC), bio);
1158         while (atomic_read(&io_done))
1159                 yield();
1160
1161  Done:
1162         bio_put(bio);
1163         return error;
1164 }
1165
1166 static int bio_read_page(pgoff_t page_off, void * page)
1167 {
1168         return submit(READ, page_off, page);
1169 }
1170
1171 static int bio_write_page(pgoff_t page_off, void * page)
1172 {
1173         return submit(WRITE, page_off, page);
1174 }
1175
1176 /*
1177  * Sanity check if this image makes sense with this kernel/swap context
1178  * I really don't think that it's foolproof but more than nothing..
1179  */
1180
1181 static const char * sanity_check(void)
1182 {
1183         dump_info();
1184         if(swsusp_info.version_code != LINUX_VERSION_CODE)
1185                 return "kernel version";
1186         if(swsusp_info.num_physpages != num_physpages)
1187                 return "memory size";
1188         if (strcmp(swsusp_info.uts.sysname,system_utsname.sysname))
1189                 return "system type";
1190         if (strcmp(swsusp_info.uts.release,system_utsname.release))
1191                 return "kernel release";
1192         if (strcmp(swsusp_info.uts.version,system_utsname.version))
1193                 return "version";
1194         if (strcmp(swsusp_info.uts.machine,system_utsname.machine))
1195                 return "machine";
1196         if(swsusp_info.cpus != num_online_cpus())
1197                 return "number of cpus";
1198         return NULL;
1199 }
1200
1201
1202 static int check_header(void)
1203 {
1204         const char * reason = NULL;
1205         int error;
1206
1207         if ((error = bio_read_page(swp_offset(swsusp_header.swsusp_info), &swsusp_info)))
1208                 return error;
1209
1210         /* Is this same machine? */
1211         if ((reason = sanity_check())) {
1212                 printk(KERN_ERR "swsusp: Resume mismatch: %s\n",reason);
1213                 return -EPERM;
1214         }
1215         nr_copy_pages = swsusp_info.image_pages;
1216         return error;
1217 }
1218
1219 static int check_sig(void)
1220 {
1221         int error;
1222
1223         memset(&swsusp_header, 0, sizeof(swsusp_header));
1224         if ((error = bio_read_page(0, &swsusp_header)))
1225                 return error;
1226         if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
1227                 memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
1228
1229                 /*
1230                  * Reset swap signature now.
1231                  */
1232                 error = bio_write_page(0, &swsusp_header);
1233         } else {
1234                 printk(KERN_ERR "swsusp: Suspend partition has wrong signature?\n");
1235                 return -EINVAL;
1236         }
1237         if (!error)
1238                 pr_debug("swsusp: Signature found, resuming\n");
1239         return error;
1240 }
1241
1242 /**
1243  *      data_read - Read image pages from swap.
1244  *
1245  *      You do not need to check for overlaps, check_pagedir()
1246  *      already did that.
1247  */
1248
1249 static int data_read(struct pbe *pblist)
1250 {
1251         struct pbe * p;
1252         int error = 0;
1253         int i = 0;
1254         int mod = swsusp_info.image_pages / 100;
1255
1256         if (!mod)
1257                 mod = 1;
1258
1259         printk("swsusp: Reading image data (%lu pages):     ",
1260                         swsusp_info.image_pages);
1261
1262         for_each_pbe (p, pblist) {
1263                 if (!(i % mod))
1264                         printk("\b\b\b\b%3d%%", i / mod);
1265
1266                 error = bio_read_page(swp_offset(p->swap_address),
1267                                   (void *)p->address);
1268                 if (error)
1269                         return error;
1270
1271                 i++;
1272         }
1273         printk("\b\b\b\bdone\n");
1274         return error;
1275 }
1276
1277 extern dev_t name_to_dev_t(const char *line);
1278
1279 /**
1280  *      read_pagedir - Read page backup list pages from swap
1281  */
1282
1283 static int read_pagedir(struct pbe *pblist)
1284 {
1285         struct pbe *pbpage, *p;
1286         unsigned i = 0;
1287         int error;
1288
1289         if (!pblist)
1290                 return -EFAULT;
1291
1292         printk("swsusp: Reading pagedir (%lu pages)\n",
1293                         swsusp_info.pagedir_pages);
1294
1295         for_each_pb_page (pbpage, pblist) {
1296                 unsigned long offset = swp_offset(swsusp_info.pagedir[i++]);
1297
1298                 error = -EFAULT;
1299                 if (offset) {
1300                         p = (pbpage + PB_PAGE_SKIP)->next;
1301                         error = bio_read_page(offset, (void *)pbpage);
1302                         (pbpage + PB_PAGE_SKIP)->next = p;
1303                 }
1304                 if (error)
1305                         break;
1306         }
1307
1308         if (error)
1309                 free_page((unsigned long)pblist);
1310
1311         BUG_ON(i != swsusp_info.pagedir_pages);
1312
1313         return error;
1314 }
1315
1316
1317 static int check_suspend_image(void)
1318 {
1319         int error = 0;
1320
1321         if ((error = check_sig()))
1322                 return error;
1323
1324         if ((error = check_header()))
1325                 return error;
1326
1327         return 0;
1328 }
1329
1330 static int read_suspend_image(void)
1331 {
1332         int error = 0;
1333         struct pbe *p;
1334
1335         if (!(p = alloc_pagedir(nr_copy_pages)))
1336                 return -ENOMEM;
1337
1338         if ((error = read_pagedir(p)))
1339                 return error;
1340
1341         create_pbe_list(p, nr_copy_pages);
1342
1343         if (!(pagedir_nosave = swsusp_pagedir_relocate(p)))
1344                 return -ENOMEM;
1345
1346         /* Allocate memory for the image and read the data from swap */
1347
1348         error = check_pagedir(pagedir_nosave);
1349         free_eaten_memory();
1350         if (!error)
1351                 error = data_read(pagedir_nosave);
1352
1353         if (error) { /* We fail cleanly */
1354                 for_each_pbe (p, pagedir_nosave)
1355                         if (p->address) {
1356                                 free_page(p->address);
1357                                 p->address = 0UL;
1358                         }
1359                 free_pagedir(pagedir_nosave);
1360         }
1361         return error;
1362 }
1363
1364 /**
1365  *      swsusp_check - Check for saved image in swap
1366  */
1367
1368 int swsusp_check(void)
1369 {
1370         int error;
1371
1372         if (!swsusp_resume_device) {
1373                 if (!strlen(resume_file))
1374                         return -ENOENT;
1375                 swsusp_resume_device = name_to_dev_t(resume_file);
1376                 pr_debug("swsusp: Resume From Partition %s\n", resume_file);
1377         } else {
1378                 pr_debug("swsusp: Resume From Partition %d:%d\n",
1379                          MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
1380         }
1381
1382         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
1383         if (!IS_ERR(resume_bdev)) {
1384                 set_blocksize(resume_bdev, PAGE_SIZE);
1385                 error = check_suspend_image();
1386                 if (error)
1387                     blkdev_put(resume_bdev);
1388         } else
1389                 error = PTR_ERR(resume_bdev);
1390
1391         if (!error)
1392                 pr_debug("swsusp: resume file found\n");
1393         else
1394                 pr_debug("swsusp: Error %d check for resume file\n", error);
1395         return error;
1396 }
1397
1398 /**
1399  *      swsusp_read - Read saved image from swap.
1400  */
1401
1402 int swsusp_read(void)
1403 {
1404         int error;
1405
1406         if (IS_ERR(resume_bdev)) {
1407                 pr_debug("swsusp: block device not initialised\n");
1408                 return PTR_ERR(resume_bdev);
1409         }
1410
1411         error = read_suspend_image();
1412         blkdev_put(resume_bdev);
1413
1414         if (!error)
1415                 pr_debug("swsusp: Reading resume file was successful\n");
1416         else
1417                 pr_debug("swsusp: Error %d resuming\n", error);
1418         return error;
1419 }
1420
1421 /**
1422  *      swsusp_close - close swap device.
1423  */
1424
1425 void swsusp_close(void)
1426 {
1427         if (IS_ERR(resume_bdev)) {
1428                 pr_debug("swsusp: block device not initialised\n");
1429                 return;
1430         }
1431
1432         blkdev_put(resume_bdev);
1433 }