git.oblomov.eu Git - linux-2.6/blob - kernel/power/swsusp.c

   1 /*
   2  * linux/kernel/power/swsusp.c
   3  *
   4  * This file provides code to write suspend image to swap and read it back.
   5  *
   6  * Copyright (C) 1998-2001 Gabor Kuti <seasons@fornax.hu>
   7  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
   8  *
   9  * This file is released under the GPLv2.
  10  *
  11  * I'd like to thank the following people for their work:
  12  *
  13  * Pavel Machek <pavel@ucw.cz>:
  14  * Modifications, defectiveness pointing, being with me at the very beginning,
  15  * suspend to swap space, stop all tasks. Port to 2.4.18-ac and 2.5.17.
  16  *
  17  * Steve Doddi <dirk@loth.demon.co.uk>:
  18  * Support the possibility of hardware state restoring.
  19  *
  20  * Raph <grey.havens@earthling.net>:
  21  * Support for preserving states of network devices and virtual console
  22  * (including X and svgatextmode)
  23  *
  24  * Kurt Garloff <garloff@suse.de>:
  25  * Straightened the critical function in order to prevent compilers from
  26  * playing tricks with local variables.
  27  *
  28  * Andreas Mohr <a.mohr@mailto.de>
  29  *
  30  * Alex Badea <vampire@go.ro>:
  31  * Fixed runaway init
  32  *
  33  * Andreas Steinmetz <ast@domdv.de>:
  34  * Added encrypted suspend option
  35  *
  36  * More state savers are welcome. Especially for the scsi layer...
  37  *
  38  * For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
  39  */
  40
  41 #include <linux/module.h>
  42 #include <linux/mm.h>
  43 #include <linux/suspend.h>
  44 #include <linux/smp_lock.h>
  45 #include <linux/file.h>
  46 #include <linux/utsname.h>
  47 #include <linux/version.h>
  48 #include <linux/delay.h>
  49 #include <linux/bitops.h>
  50 #include <linux/spinlock.h>
  51 #include <linux/genhd.h>
  52 #include <linux/kernel.h>
  53 #include <linux/major.h>
  54 #include <linux/swap.h>
  55 #include <linux/pm.h>
  56 #include <linux/device.h>
  57 #include <linux/buffer_head.h>
  58 #include <linux/swapops.h>
  59 #include <linux/bootmem.h>
  60 #include <linux/syscalls.h>
  61 #include <linux/highmem.h>
  62 #include <linux/bio.h>
  63
  64 #include <asm/uaccess.h>
  65 #include <asm/mmu_context.h>
  66 #include <asm/pgtable.h>
  67 #include <asm/tlbflush.h>
  68 #include <asm/io.h>
  69
  70 #include <linux/random.h>
  71 #include <linux/crypto.h>
  72 #include <asm/scatterlist.h>
  73
  74 #include "power.h"
  75
  76 #define CIPHER "aes"
  77 #define MAXKEY 32
  78 #define MAXIV  32
  79
  80 extern char resume_file[];
  81
  82 /* Local variables that should not be affected by save */
  83 unsigned int nr_copy_pages __nosavedata = 0;
  84
  85 /* Suspend pagedir is allocated before final copy, therefore it
  86    must be freed after resume
  87
  88    Warning: this is evil. There are actually two pagedirs at time of
  89    resume. One is "pagedir_save", which is empty frame allocated at
  90    time of suspend, that must be freed. Second is "pagedir_nosave",
  91    allocated at time of resume, that travels through memory not to
  92    collide with anything.
  93
  94    Warning: this is even more evil than it seems. Pagedirs this file
  95    talks about are completely different from page directories used by
  96    MMU hardware.
  97  */
  98 suspend_pagedir_t *pagedir_nosave __nosavedata = NULL;
  99 suspend_pagedir_t *pagedir_save;
 100
 101 #define SWSUSP_SIG      "S1SUSPEND"
 102
 103 static struct swsusp_header {
 104         char reserved[PAGE_SIZE - 20 - MAXKEY - MAXIV - sizeof(swp_entry_t)];
 105         u8 key_iv[MAXKEY+MAXIV];
 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  * Saving part...
 115  */
 116
 117 /* We memorize in swapfile_used what swap devices are used for suspension */
 118 #define SWAPFILE_UNUSED    0
 119 #define SWAPFILE_SUSPEND   1    /* This is the suspending device */
 120 #define SWAPFILE_IGNORED   2    /* Those are other swap devices ignored for suspension */
 121
 122 static unsigned short swapfile_used[MAX_SWAPFILES];
 123 static unsigned short root_swap;
 124
 125 static int write_page(unsigned long addr, swp_entry_t * loc);
 126 static int bio_read_page(pgoff_t page_off, void * page);
 127
 128 static u8 key_iv[MAXKEY+MAXIV];
 129
 130 #ifdef CONFIG_SWSUSP_ENCRYPT
 131
 132 static int crypto_init(int mode, void **mem)
 133 {
 134         int error = 0;
 135         int len;
 136         char *modemsg;
 137         struct crypto_tfm *tfm;
 138
 139         modemsg = mode ? "suspend not possible" : "resume not possible";
 140
 141         tfm = crypto_alloc_tfm(CIPHER, CRYPTO_TFM_MODE_CBC);
 142         if(!tfm) {
 143                 printk(KERN_ERR "swsusp: no tfm, %s\n", modemsg);
 144                 error = -EINVAL;
 145                 goto out;
 146         }
 147
 148         if(MAXKEY < crypto_tfm_alg_min_keysize(tfm)) {
 149                 printk(KERN_ERR "swsusp: key buffer too small, %s\n", modemsg);
 150                 error = -ENOKEY;
 151                 goto fail;
 152         }
 153
 154         if (mode)
 155                 get_random_bytes(key_iv, MAXKEY+MAXIV);
 156
 157         len = crypto_tfm_alg_max_keysize(tfm);
 158         if (len > MAXKEY)
 159                 len = MAXKEY;
 160
 161         if (crypto_cipher_setkey(tfm, key_iv, len)) {
 162                 printk(KERN_ERR "swsusp: key setup failure, %s\n", modemsg);
 163                 error = -EKEYREJECTED;
 164                 goto fail;
 165         }
 166
 167         len = crypto_tfm_alg_ivsize(tfm);
 168
 169         if (MAXIV < len) {
 170                 printk(KERN_ERR "swsusp: iv buffer too small, %s\n", modemsg);
 171                 error = -EOVERFLOW;
 172                 goto fail;
 173         }
 174
 175         crypto_cipher_set_iv(tfm, key_iv+MAXKEY, len);
 176
 177         *mem=(void *)tfm;
 178
 179         goto out;
 180
 181 fail:   crypto_free_tfm(tfm);
 182 out:    return error;
 183 }
 184
 185 static __inline__ void crypto_exit(void *mem)
 186 {
 187         crypto_free_tfm((struct crypto_tfm *)mem);
 188 }
 189
 190 static __inline__ int crypto_write(struct pbe *p, void *mem)
 191 {
 192         int error = 0;
 193         struct scatterlist src, dst;
 194
 195         src.page   = virt_to_page(p->address);
 196         src.offset = 0;
 197         src.length = PAGE_SIZE;
 198         dst.page   = virt_to_page((void *)&swsusp_header);
 199         dst.offset = 0;
 200         dst.length = PAGE_SIZE;
 201
 202         error = crypto_cipher_encrypt((struct crypto_tfm *)mem, &dst, &src,
 203                                         PAGE_SIZE);
 204
 205         if (!error)
 206                 error = write_page((unsigned long)&swsusp_header,
 207                                 &(p->swap_address));
 208         return error;
 209 }
 210
 211 static __inline__ int crypto_read(struct pbe *p, void *mem)
 212 {
 213         int error = 0;
 214         struct scatterlist src, dst;
 215
 216         error = bio_read_page(swp_offset(p->swap_address), (void *)p->address);
 217         if (!error) {
 218                 src.offset = 0;
 219                 src.length = PAGE_SIZE;
 220                 dst.offset = 0;
 221                 dst.length = PAGE_SIZE;
 222                 src.page = dst.page = virt_to_page((void *)p->address);
 223
 224                 error = crypto_cipher_decrypt((struct crypto_tfm *)mem, &dst,
 225                                                 &src, PAGE_SIZE);
 226         }
 227         return error;
 228 }
 229 #else
 230 static __inline__ int crypto_init(int mode, void *mem)
 231 {
 232         return 0;
 233 }
 234
 235 static __inline__ void crypto_exit(void *mem)
 236 {
 237 }
 238
 239 static __inline__ int crypto_write(struct pbe *p, void *mem)
 240 {
 241         return write_page(p->address, &(p->swap_address));
 242 }
 243
 244 static __inline__ int crypto_read(struct pbe *p, void *mem)
 245 {
 246         return bio_read_page(swp_offset(p->swap_address), (void *)p->address);
 247 }
 248 #endif
 249
 250 static int mark_swapfiles(swp_entry_t prev)
 251 {
 252         int error;
 253
 254         rw_swap_page_sync(READ,
 255                           swp_entry(root_swap, 0),
 256                           virt_to_page((unsigned long)&swsusp_header));
 257         if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
 258             !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
 259                 memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
 260                 memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
 261                 memcpy(swsusp_header.key_iv, key_iv, MAXKEY+MAXIV);
 262                 swsusp_header.swsusp_info = prev;
 263                 error = rw_swap_page_sync(WRITE,
 264                                           swp_entry(root_swap, 0),
 265                                           virt_to_page((unsigned long)
 266                                                        &swsusp_header));
 267         } else {
 268                 pr_debug("swsusp: Partition is not swap space.\n");
 269                 error = -ENODEV;
 270         }
 271         return error;
 272 }
 273
 274 /*
 275  * Check whether the swap device is the specified resume
 276  * device, irrespective of whether they are specified by
 277  * identical names.
 278  *
 279  * (Thus, device inode aliasing is allowed.  You can say /dev/hda4
 280  * instead of /dev/ide/host0/bus0/target0/lun0/part4 [if using devfs]
 281  * and they'll be considered the same device.  This is *necessary* for
 282  * devfs, since the resume code can only recognize the form /dev/hda4,
 283  * but the suspend code would see the long name.)
 284  */
 285 static int is_resume_device(const struct swap_info_struct *swap_info)
 286 {
 287         struct file *file = swap_info->swap_file;
 288         struct inode *inode = file->f_dentry->d_inode;
 289
 290         return S_ISBLK(inode->i_mode) &&
 291                 swsusp_resume_device == MKDEV(imajor(inode), iminor(inode));
 292 }
 293
 294 static int swsusp_swap_check(void) /* This is called before saving image */
 295 {
 296         int i, len;
 297
 298         len=strlen(resume_file);
 299         root_swap = 0xFFFF;
 300
 301         spin_lock(&swap_lock);
 302         for (i=0; i<MAX_SWAPFILES; i++) {
 303                 if (!(swap_info[i].flags & SWP_WRITEOK)) {
 304                         swapfile_used[i]=SWAPFILE_UNUSED;
 305                 } else {
 306                         if (!len) {
 307                                 printk(KERN_WARNING "resume= option should be used to set suspend device" );
 308                                 if (root_swap == 0xFFFF) {
 309                                         swapfile_used[i] = SWAPFILE_SUSPEND;
 310                                         root_swap = i;
 311                                 } else
 312                                         swapfile_used[i] = SWAPFILE_IGNORED;
 313                         } else {
 314                                 /* we ignore all swap devices that are not the resume_file */
 315                                 if (is_resume_device(&swap_info[i])) {
 316                                         swapfile_used[i] = SWAPFILE_SUSPEND;
 317                                         root_swap = i;
 318                                 } else {
 319                                         swapfile_used[i] = SWAPFILE_IGNORED;
 320                                 }
 321                         }
 322                 }
 323         }
 324         spin_unlock(&swap_lock);
 325         return (root_swap != 0xffff) ? 0 : -ENODEV;
 326 }
 327
 328 /**
 329  * This is called after saving image so modification
 330  * will be lost after resume... and that's what we want.
 331  * we make the device unusable. A new call to
 332  * lock_swapdevices can unlock the devices.
 333  */
 334 static void lock_swapdevices(void)
 335 {
 336         int i;
 337
 338         spin_lock(&swap_lock);
 339         for (i = 0; i< MAX_SWAPFILES; i++)
 340                 if (swapfile_used[i] == SWAPFILE_IGNORED) {
 341                         swap_info[i].flags ^= SWP_WRITEOK;
 342                 }
 343         spin_unlock(&swap_lock);
 344 }
 345
 346 /**
 347  *      write_page - Write one page to a fresh swap location.
 348  *      @addr:  Address we're writing.
 349  *      @loc:   Place to store the entry we used.
 350  *
 351  *      Allocate a new swap entry and 'sync' it. Note we discard -EIO
 352  *      errors. That is an artifact left over from swsusp. It did not
 353  *      check the return of rw_swap_page_sync() at all, since most pages
 354  *      written back to swap would return -EIO.
 355  *      This is a partial improvement, since we will at least return other
 356  *      errors, though we need to eventually fix the damn code.
 357  */
 358 static int write_page(unsigned long addr, swp_entry_t * loc)
 359 {
 360         swp_entry_t entry;
 361         int error = 0;
 362
 363         entry = get_swap_page();
 364         if (swp_offset(entry) &&
 365             swapfile_used[swp_type(entry)] == SWAPFILE_SUSPEND) {
 366                 error = rw_swap_page_sync(WRITE, entry,
 367                                           virt_to_page(addr));
 368                 if (error == -EIO)
 369                         error = 0;
 370                 if (!error)
 371                         *loc = entry;
 372         } else
 373                 error = -ENOSPC;
 374         return error;
 375 }
 376
 377 /**
 378  *      data_free - Free the swap entries used by the saved image.
 379  *
 380  *      Walk the list of used swap entries and free each one.
 381  *      This is only used for cleanup when suspend fails.
 382  */
 383 static void data_free(void)
 384 {
 385         swp_entry_t entry;
 386         struct pbe * p;
 387
 388         for_each_pbe(p, pagedir_nosave) {
 389                 entry = p->swap_address;
 390                 if (entry.val)
 391                         swap_free(entry);
 392                 else
 393                         break;
 394         }
 395 }
 396
 397 /**
 398  *      data_write - Write saved image to swap.
 399  *
 400  *      Walk the list of pages in the image and sync each one to swap.
 401  */
 402 static int data_write(void)
 403 {
 404         int error = 0, i = 0;
 405         unsigned int mod = nr_copy_pages / 100;
 406         struct pbe *p;
 407         void *tfm;
 408
 409         if ((error = crypto_init(1, &tfm)))
 410                 return error;
 411
 412         if (!mod)
 413                 mod = 1;
 414
 415         printk( "Writing data to swap (%d pages)...     ", nr_copy_pages );
 416         for_each_pbe (p, pagedir_nosave) {
 417                 if (!(i%mod))
 418                         printk( "\b\b\b\b%3d%%", i / mod );
 419                 if ((error = crypto_write(p, tfm))) {
 420                         crypto_exit(tfm);
 421                         return error;
 422                 }
 423                 i++;
 424         }
 425         printk("\b\b\b\bdone\n");
 426         crypto_exit(tfm);
 427         return error;
 428 }
 429
 430 static void dump_info(void)
 431 {
 432         pr_debug(" swsusp: Version: %u\n",swsusp_info.version_code);
 433         pr_debug(" swsusp: Num Pages: %ld\n",swsusp_info.num_physpages);
 434         pr_debug(" swsusp: UTS Sys: %s\n",swsusp_info.uts.sysname);
 435         pr_debug(" swsusp: UTS Node: %s\n",swsusp_info.uts.nodename);
 436         pr_debug(" swsusp: UTS Release: %s\n",swsusp_info.uts.release);
 437         pr_debug(" swsusp: UTS Version: %s\n",swsusp_info.uts.version);
 438         pr_debug(" swsusp: UTS Machine: %s\n",swsusp_info.uts.machine);
 439         pr_debug(" swsusp: UTS Domain: %s\n",swsusp_info.uts.domainname);
 440         pr_debug(" swsusp: CPUs: %d\n",swsusp_info.cpus);
 441         pr_debug(" swsusp: Image: %ld Pages\n",swsusp_info.image_pages);
 442         pr_debug(" swsusp: Pagedir: %ld Pages\n",swsusp_info.pagedir_pages);
 443 }
 444
 445 static void init_header(void)
 446 {
 447         memset(&swsusp_info, 0, sizeof(swsusp_info));
 448         swsusp_info.version_code = LINUX_VERSION_CODE;
 449         swsusp_info.num_physpages = num_physpages;
 450         memcpy(&swsusp_info.uts, &system_utsname, sizeof(system_utsname));
 451
 452         swsusp_info.suspend_pagedir = pagedir_nosave;
 453         swsusp_info.cpus = num_online_cpus();
 454         swsusp_info.image_pages = nr_copy_pages;
 455 }
 456
 457 static int close_swap(void)
 458 {
 459         swp_entry_t entry;
 460         int error;
 461
 462         dump_info();
 463         error = write_page((unsigned long)&swsusp_info, &entry);
 464         if (!error) {
 465                 printk( "S" );
 466                 error = mark_swapfiles(entry);
 467                 printk( "|\n" );
 468         }
 469         return error;
 470 }
 471
 472 /**
 473  *      free_pagedir_entries - Free pages used by the page directory.
 474  *
 475  *      This is used during suspend for error recovery.
 476  */
 477
 478 static void free_pagedir_entries(void)
 479 {
 480         int i;
 481
 482         for (i = 0; i < swsusp_info.pagedir_pages; i++)
 483                 swap_free(swsusp_info.pagedir[i]);
 484 }
 485
 486
 487 /**
 488  *      write_pagedir - Write the array of pages holding the page directory.
 489  *      @last:  Last swap entry we write (needed for header).
 490  */
 491
 492 static int write_pagedir(void)
 493 {
 494         int error = 0;
 495         unsigned n = 0;
 496         struct pbe * pbe;
 497
 498         printk( "Writing pagedir...");
 499         for_each_pb_page (pbe, pagedir_nosave) {
 500                 if ((error = write_page((unsigned long)pbe, &swsusp_info.pagedir[n++])))
 501                         return error;
 502         }
 503
 504         swsusp_info.pagedir_pages = n;
 505         printk("done (%u pages)\n", n);
 506         return error;
 507 }
 508
 509 /**
 510  *      write_suspend_image - Write entire image and metadata.
 511  *
 512  */
 513 static int write_suspend_image(void)
 514 {
 515         int error;
 516
 517         init_header();
 518         if ((error = data_write()))
 519                 goto FreeData;
 520
 521         if ((error = write_pagedir()))
 522                 goto FreePagedir;
 523
 524         if ((error = close_swap()))
 525                 goto FreePagedir;
 526  Done:
 527         memset(key_iv, 0, MAXKEY+MAXIV);
 528         return error;
 529  FreePagedir:
 530         free_pagedir_entries();
 531  FreeData:
 532         data_free();
 533         goto Done;
 534 }
 535
 536 /**
 537  *      enough_swap - Make sure we have enough swap to save the image.
 538  *
 539  *      Returns TRUE or FALSE after checking the total amount of swap
 540  *      space avaiable.
 541  *
 542  *      FIXME: si_swapinfo(&i) returns all swap devices information.
 543  *      We should only consider resume_device.
 544  */
 545
 546 int enough_swap(unsigned nr_pages)
 547 {
 548         struct sysinfo i;
 549
 550         si_swapinfo(&i);
 551         pr_debug("swsusp: available swap: %lu pages\n", i.freeswap);
 552         return i.freeswap > (nr_pages + PAGES_FOR_IO +
 553                 (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
 554 }
 555
 556
 557 /* It is important _NOT_ to umount filesystems at this point. We want
 558  * them synced (in case something goes wrong) but we DO not want to mark
 559  * filesystem clean: it is not. (And it does not matter, if we resume
 560  * correctly, we'll mark system clean, anyway.)
 561  */
 562 int swsusp_write(void)
 563 {
 564         int error;
 565
 566         lock_swapdevices();
 567         error = write_suspend_image();
 568         /* This will unlock ignored swap devices since writing is finished */
 569         lock_swapdevices();
 570         return error;
 571
 572 }
 573
 574
 575
 576 int swsusp_suspend(void)
 577 {
 578         int error;
 579         if ((error = arch_prepare_suspend()))
 580                 return error;
 581         local_irq_disable();
 582         /* At this point, device_suspend() has been called, but *not*
 583          * device_power_down(). We *must* device_power_down() now.
 584          * Otherwise, drivers for some devices (e.g. interrupt controllers)
 585          * become desynchronized with the actual state of the hardware
 586          * at resume time, and evil weirdness ensues.
 587          */
 588         if ((error = device_power_down(PMSG_FREEZE))) {
 589                 printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
 590                 local_irq_enable();
 591                 return error;
 592         }
 593
 594         if ((error = swsusp_swap_check())) {
 595                 printk(KERN_ERR "swsusp: cannot find swap device, try swapon -a.\n");
 596                 device_power_up();
 597                 local_irq_enable();
 598                 return error;
 599         }
 600
 601         save_processor_state();
 602         if ((error = swsusp_arch_suspend()))
 603                 printk(KERN_ERR "Error %d suspending\n", error);
 604         /* Restore control flow magically appears here */
 605         restore_processor_state();
 606         restore_highmem();
 607         device_power_up();
 608         local_irq_enable();
 609         return error;
 610 }
 611
 612 int swsusp_resume(void)
 613 {
 614         int error;
 615         local_irq_disable();
 616         if (device_power_down(PMSG_FREEZE))
 617                 printk(KERN_ERR "Some devices failed to power down, very bad\n");
 618         /* We'll ignore saved state, but this gets preempt count (etc) right */
 619         save_processor_state();
 620         error = swsusp_arch_resume();
 621         /* Code below is only ever reached in case of failure. Otherwise
 622          * execution continues at place where swsusp_arch_suspend was called
 623          */
 624         BUG_ON(!error);
 625         /* The only reason why swsusp_arch_resume() can fail is memory being
 626          * very tight, so we have to free it as soon as we can to avoid
 627          * subsequent failures
 628          */
 629         swsusp_free();
 630         restore_processor_state();
 631         restore_highmem();
 632         touch_softlockup_watchdog();
 633         device_power_up();
 634         local_irq_enable();
 635         return error;
 636 }
 637
 638 /**
 639  *      On resume, for storing the PBE list and the image,
 640  *      we can only use memory pages that do not conflict with the pages
 641  *      which had been used before suspend.
 642  *
 643  *      We don't know which pages are usable until we allocate them.
 644  *
 645  *      Allocated but unusable (ie eaten) memory pages are marked so that
 646  *      swsusp_free() can release them
 647  */
 648
 649 unsigned long get_safe_page(gfp_t gfp_mask)
 650 {
 651         unsigned long m;
 652
 653         do {
 654                 m = get_zeroed_page(gfp_mask);
 655                 if (m && PageNosaveFree(virt_to_page(m)))
 656                         /* This is for swsusp_free() */
 657                         SetPageNosave(virt_to_page(m));
 658         } while (m && PageNosaveFree(virt_to_page(m)));
 659         if (m) {
 660                 /* This is for swsusp_free() */
 661                 SetPageNosave(virt_to_page(m));
 662                 SetPageNosaveFree(virt_to_page(m));
 663         }
 664         return m;
 665 }
 666
 667 /**
 668  *      check_pagedir - We ensure here that pages that the PBEs point to
 669  *      won't collide with pages where we're going to restore from the loaded
 670  *      pages later
 671  */
 672
 673 static int check_pagedir(struct pbe *pblist)
 674 {
 675         struct pbe *p;
 676
 677         /* This is necessary, so that we can free allocated pages
 678          * in case of failure
 679          */
 680         for_each_pbe (p, pblist)
 681                 p->address = 0UL;
 682
 683         for_each_pbe (p, pblist) {
 684                 p->address = get_safe_page(GFP_ATOMIC);
 685                 if (!p->address)
 686                         return -ENOMEM;
 687         }
 688         return 0;
 689 }
 690
 691 /**
 692  *      swsusp_pagedir_relocate - It is possible, that some memory pages
 693  *      occupied by the list of PBEs collide with pages where we're going to
 694  *      restore from the loaded pages later.  We relocate them here.
 695  */
 696
 697 static struct pbe * swsusp_pagedir_relocate(struct pbe *pblist)
 698 {
 699         struct zone *zone;
 700         unsigned long zone_pfn;
 701         struct pbe *pbpage, *tail, *p;
 702         void *m;
 703         int rel = 0;
 704
 705         if (!pblist) /* a sanity check */
 706                 return NULL;
 707
 708         pr_debug("swsusp: Relocating pagedir (%lu pages to check)\n",
 709                         swsusp_info.pagedir_pages);
 710
 711         /* Clear page flags */
 712
 713         for_each_zone (zone) {
 714                 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
 715                         if (pfn_valid(zone_pfn + zone->zone_start_pfn))
 716                                 ClearPageNosaveFree(pfn_to_page(zone_pfn +
 717                                         zone->zone_start_pfn));
 718         }
 719
 720         /* Mark orig addresses */
 721
 722         for_each_pbe (p, pblist)
 723                 SetPageNosaveFree(virt_to_page(p->orig_address));
 724
 725         tail = pblist + PB_PAGE_SKIP;
 726
 727         /* Relocate colliding pages */
 728
 729         for_each_pb_page (pbpage, pblist) {
 730                 if (PageNosaveFree(virt_to_page((unsigned long)pbpage))) {
 731                         m = (void *)get_safe_page(GFP_ATOMIC | __GFP_COLD);
 732                         if (!m)
 733                                 return NULL;
 734                         memcpy(m, (void *)pbpage, PAGE_SIZE);
 735                         if (pbpage == pblist)
 736                                 pblist = (struct pbe *)m;
 737                         else
 738                                 tail->next = (struct pbe *)m;
 739                         pbpage = (struct pbe *)m;
 740
 741                         /* We have to link the PBEs again */
 742                         for (p = pbpage; p < pbpage + PB_PAGE_SKIP; p++)
 743                                 if (p->next) /* needed to save the end */
 744                                         p->next = p + 1;
 745
 746                         rel++;
 747                 }
 748                 tail = pbpage + PB_PAGE_SKIP;
 749         }
 750
 751         /* This is for swsusp_free() */
 752         for_each_pb_page (pbpage, pblist) {
 753                 SetPageNosave(virt_to_page(pbpage));
 754                 SetPageNosaveFree(virt_to_page(pbpage));
 755         }
 756
 757         printk("swsusp: Relocated %d pages\n", rel);
 758
 759         return pblist;
 760 }
 761
 762 /*
 763  *      Using bio to read from swap.
 764  *      This code requires a bit more work than just using buffer heads
 765  *      but, it is the recommended way for 2.5/2.6.
 766  *      The following are to signal the beginning and end of I/O. Bios
 767  *      finish asynchronously, while we want them to happen synchronously.
 768  *      A simple atomic_t, and a wait loop take care of this problem.
 769  */
 770
 771 static atomic_t io_done = ATOMIC_INIT(0);
 772
 773 static int end_io(struct bio * bio, unsigned int num, int err)
 774 {
 775         if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
 776                 panic("I/O error reading memory image");
 777         atomic_set(&io_done, 0);
 778         return 0;
 779 }
 780
 781 static struct block_device * resume_bdev;
 782
 783 /**
 784  *      submit - submit BIO request.
 785  *      @rw:    READ or WRITE.
 786  *      @off    physical offset of page.
 787  *      @page:  page we're reading or writing.
 788  *
 789  *      Straight from the textbook - allocate and initialize the bio.
 790  *      If we're writing, make sure the page is marked as dirty.
 791  *      Then submit it and wait.
 792  */
 793
 794 static int submit(int rw, pgoff_t page_off, void * page)
 795 {
 796         int error = 0;
 797         struct bio * bio;
 798
 799         bio = bio_alloc(GFP_ATOMIC, 1);
 800         if (!bio)
 801                 return -ENOMEM;
 802         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
 803         bio_get(bio);
 804         bio->bi_bdev = resume_bdev;
 805         bio->bi_end_io = end_io;
 806
 807         if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) {
 808                 printk("swsusp: ERROR: adding page to bio at %ld\n",page_off);
 809                 error = -EFAULT;
 810                 goto Done;
 811         }
 812
 813         if (rw == WRITE)
 814                 bio_set_pages_dirty(bio);
 815
 816         atomic_set(&io_done, 1);
 817         submit_bio(rw | (1 << BIO_RW_SYNC), bio);
 818         while (atomic_read(&io_done))
 819                 yield();
 820
 821  Done:
 822         bio_put(bio);
 823         return error;
 824 }
 825
 826 static int bio_read_page(pgoff_t page_off, void * page)
 827 {
 828         return submit(READ, page_off, page);
 829 }
 830
 831 static int bio_write_page(pgoff_t page_off, void * page)
 832 {
 833         return submit(WRITE, page_off, page);
 834 }
 835
 836 /*
 837  * Sanity check if this image makes sense with this kernel/swap context
 838  * I really don't think that it's foolproof but more than nothing..
 839  */
 840
 841 static const char * sanity_check(void)
 842 {
 843         dump_info();
 844         if (swsusp_info.version_code != LINUX_VERSION_CODE)
 845                 return "kernel version";
 846         if (swsusp_info.num_physpages != num_physpages)
 847                 return "memory size";
 848         if (strcmp(swsusp_info.uts.sysname,system_utsname.sysname))
 849                 return "system type";
 850         if (strcmp(swsusp_info.uts.release,system_utsname.release))
 851                 return "kernel release";
 852         if (strcmp(swsusp_info.uts.version,system_utsname.version))
 853                 return "version";
 854         if (strcmp(swsusp_info.uts.machine,system_utsname.machine))
 855                 return "machine";
 856 #if 0
 857         /* We can't use number of online CPUs when we use hotplug to remove them ;-))) */
 858         if (swsusp_info.cpus != num_possible_cpus())
 859                 return "number of cpus";
 860 #endif
 861         return NULL;
 862 }
 863
 864
 865 static int check_header(void)
 866 {
 867         const char * reason = NULL;
 868         int error;
 869
 870         if ((error = bio_read_page(swp_offset(swsusp_header.swsusp_info), &swsusp_info)))
 871                 return error;
 872
 873         /* Is this same machine? */
 874         if ((reason = sanity_check())) {
 875                 printk(KERN_ERR "swsusp: Resume mismatch: %s\n",reason);
 876                 return -EPERM;
 877         }
 878         nr_copy_pages = swsusp_info.image_pages;
 879         return error;
 880 }
 881
 882 static int check_sig(void)
 883 {
 884         int error;
 885
 886         memset(&swsusp_header, 0, sizeof(swsusp_header));
 887         if ((error = bio_read_page(0, &swsusp_header)))
 888                 return error;
 889         if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
 890                 memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
 891                 memcpy(key_iv, swsusp_header.key_iv, MAXKEY+MAXIV);
 892                 memset(swsusp_header.key_iv, 0, MAXKEY+MAXIV);
 893
 894                 /*
 895                  * Reset swap signature now.
 896                  */
 897                 error = bio_write_page(0, &swsusp_header);
 898         } else {
 899                 return -EINVAL;
 900         }
 901         if (!error)
 902                 pr_debug("swsusp: Signature found, resuming\n");
 903         return error;
 904 }
 905
 906 /**
 907  *      data_read - Read image pages from swap.
 908  *
 909  *      You do not need to check for overlaps, check_pagedir()
 910  *      already did that.
 911  */
 912
 913 static int data_read(struct pbe *pblist)
 914 {
 915         struct pbe * p;
 916         int error = 0;
 917         int i = 0;
 918         int mod = swsusp_info.image_pages / 100;
 919         void *tfm;
 920
 921         if ((error = crypto_init(0, &tfm)))
 922                 return error;
 923
 924         if (!mod)
 925                 mod = 1;
 926
 927         printk("swsusp: Reading image data (%lu pages):     ",
 928                         swsusp_info.image_pages);
 929
 930         for_each_pbe (p, pblist) {
 931                 if (!(i % mod))
 932                         printk("\b\b\b\b%3d%%", i / mod);
 933
 934                 if ((error = crypto_read(p, tfm))) {
 935                         crypto_exit(tfm);
 936                         return error;
 937                 }
 938
 939                 i++;
 940         }
 941         printk("\b\b\b\bdone\n");
 942         crypto_exit(tfm);
 943         return error;
 944 }
 945
 946 /**
 947  *      read_pagedir - Read page backup list pages from swap
 948  */
 949
 950 static int read_pagedir(struct pbe *pblist)
 951 {
 952         struct pbe *pbpage, *p;
 953         unsigned i = 0;
 954         int error;
 955
 956         if (!pblist)
 957                 return -EFAULT;
 958
 959         printk("swsusp: Reading pagedir (%lu pages)\n",
 960                         swsusp_info.pagedir_pages);
 961
 962         for_each_pb_page (pbpage, pblist) {
 963                 unsigned long offset = swp_offset(swsusp_info.pagedir[i++]);
 964
 965                 error = -EFAULT;
 966                 if (offset) {
 967                         p = (pbpage + PB_PAGE_SKIP)->next;
 968                         error = bio_read_page(offset, (void *)pbpage);
 969                         (pbpage + PB_PAGE_SKIP)->next = p;
 970                 }
 971                 if (error)
 972                         break;
 973         }
 974
 975         if (!error)
 976                 BUG_ON(i != swsusp_info.pagedir_pages);
 977
 978         return error;
 979 }
 980
 981
 982 static int check_suspend_image(void)
 983 {
 984         int error = 0;
 985
 986         if ((error = check_sig()))
 987                 return error;
 988
 989         if ((error = check_header()))
 990                 return error;
 991
 992         return 0;
 993 }
 994
 995 static int read_suspend_image(void)
 996 {
 997         int error = 0;
 998         struct pbe *p;
 999
1000         if (!(p = alloc_pagedir(nr_copy_pages)))
1001                 return -ENOMEM;
1002
1003         if ((error = read_pagedir(p)))
1004                 return error;
1005
1006         create_pbe_list(p, nr_copy_pages);
1007
1008         if (!(pagedir_nosave = swsusp_pagedir_relocate(p)))
1009                 return -ENOMEM;
1010
1011         /* Allocate memory for the image and read the data from swap */
1012
1013         error = check_pagedir(pagedir_nosave);
1014
1015         if (!error)
1016                 error = data_read(pagedir_nosave);
1017
1018         return error;
1019 }
1020
1021 /**
1022  *      swsusp_check - Check for saved image in swap
1023  */
1024
1025 int swsusp_check(void)
1026 {
1027         int error;
1028
1029         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
1030         if (!IS_ERR(resume_bdev)) {
1031                 set_blocksize(resume_bdev, PAGE_SIZE);
1032                 error = check_suspend_image();
1033                 if (error)
1034                     blkdev_put(resume_bdev);
1035         } else
1036                 error = PTR_ERR(resume_bdev);
1037
1038         if (!error)
1039                 pr_debug("swsusp: resume file found\n");
1040         else
1041                 pr_debug("swsusp: Error %d check for resume file\n", error);
1042         return error;
1043 }
1044
1045 /**
1046  *      swsusp_read - Read saved image from swap.
1047  */
1048
1049 int swsusp_read(void)
1050 {
1051         int error;
1052
1053         if (IS_ERR(resume_bdev)) {
1054                 pr_debug("swsusp: block device not initialised\n");
1055                 return PTR_ERR(resume_bdev);
1056         }
1057
1058         error = read_suspend_image();
1059         blkdev_put(resume_bdev);
1060         memset(key_iv, 0, MAXKEY+MAXIV);
1061
1062         if (!error)
1063                 pr_debug("swsusp: Reading resume file was successful\n");
1064         else
1065                 pr_debug("swsusp: Error %d resuming\n", error);
1066         return error;
1067 }
1068
1069 /**
1070  *      swsusp_close - close swap device.
1071  */
1072
1073 void swsusp_close(void)
1074 {
1075         if (IS_ERR(resume_bdev)) {
1076                 pr_debug("swsusp: block device not initialised\n");
1077                 return;
1078         }
1079
1080         blkdev_put(resume_bdev);
1081 }