kernel/power/snapshot.c

   1 /*
   2  * linux/kernel/power/snapshot.c
   3  *
   4  * This file provide system snapshot/restore functionality.
   5  *
   6  * Copyright (C) 1998-2005 Pavel Machek <pavel@suse.cz>
   7  *
   8  * This file is released under the GPLv2, and is based on swsusp.c.
   9  *
  10  */
  11
  12
  13 #include <linux/module.h>
  14 #include <linux/mm.h>
  15 #include <linux/suspend.h>
  16 #include <linux/smp_lock.h>
  17 #include <linux/delay.h>
  18 #include <linux/bitops.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/kernel.h>
  21 #include <linux/pm.h>
  22 #include <linux/device.h>
  23 #include <linux/bootmem.h>
  24 #include <linux/syscalls.h>
  25 #include <linux/console.h>
  26 #include <linux/highmem.h>
  27
  28 #include <asm/uaccess.h>
  29 #include <asm/mmu_context.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/tlbflush.h>
  32 #include <asm/io.h>
  33
  34 #include "power.h"
  35
  36 #ifdef CONFIG_HIGHMEM
  37 struct highmem_page {
  38         char *data;
  39         struct page *page;
  40         struct highmem_page *next;
  41 };
  42
  43 static struct highmem_page *highmem_copy;
  44
  45 static int save_highmem_zone(struct zone *zone)
  46 {
  47         unsigned long zone_pfn;
  48         mark_free_pages(zone);
  49         for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
  50                 struct page *page;
  51                 struct highmem_page *save;
  52                 void *kaddr;
  53                 unsigned long pfn = zone_pfn + zone->zone_start_pfn;
  54
  55                 if (!(pfn%1000))
  56                         printk(".");
  57                 if (!pfn_valid(pfn))
  58                         continue;
  59                 page = pfn_to_page(pfn);
  60                 /*
  61                  * This condition results from rvmalloc() sans vmalloc_32()
  62                  * and architectural memory reservations. This should be
  63                  * corrected eventually when the cases giving rise to this
  64                  * are better understood.
  65                  */
  66                 if (PageReserved(page)) {
  67                         printk("highmem reserved page?!\n");
  68                         continue;
  69                 }
  70                 BUG_ON(PageNosave(page));
  71                 if (PageNosaveFree(page))
  72                         continue;
  73                 save = kmalloc(sizeof(struct highmem_page), GFP_ATOMIC);
  74                 if (!save)
  75                         return -ENOMEM;
  76                 save->next = highmem_copy;
  77                 save->page = page;
  78                 save->data = (void *) get_zeroed_page(GFP_ATOMIC);
  79                 if (!save->data) {
  80                         kfree(save);
  81                         return -ENOMEM;
  82                 }
  83                 kaddr = kmap_atomic(page, KM_USER0);
  84                 memcpy(save->data, kaddr, PAGE_SIZE);
  85                 kunmap_atomic(kaddr, KM_USER0);
  86                 highmem_copy = save;
  87         }
  88         return 0;
  89 }
  90
  91
  92 static int save_highmem(void)
  93 {
  94         struct zone *zone;
  95         int res = 0;
  96
  97         pr_debug("swsusp: Saving Highmem\n");
  98         for_each_zone (zone) {
  99                 if (is_highmem(zone))
 100                         res = save_highmem_zone(zone);
 101                 if (res)
 102                         return res;
 103         }
 104         return 0;
 105 }
 106
 107 int restore_highmem(void)
 108 {
 109         printk("swsusp: Restoring Highmem\n");
 110         while (highmem_copy) {
 111                 struct highmem_page *save = highmem_copy;
 112                 void *kaddr;
 113                 highmem_copy = save->next;
 114
 115                 kaddr = kmap_atomic(save->page, KM_USER0);
 116                 memcpy(kaddr, save->data, PAGE_SIZE);
 117                 kunmap_atomic(kaddr, KM_USER0);
 118                 free_page((long) save->data);
 119                 kfree(save);
 120         }
 121         return 0;
 122 }
 123 #else
 124 static int save_highmem(void) { return 0; }
 125 int restore_highmem(void) { return 0; }
 126 #endif /* CONFIG_HIGHMEM */
 127
 128
 129 static int pfn_is_nosave(unsigned long pfn)
 130 {
 131         unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
 132         unsigned long nosave_end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
 133         return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
 134 }
 135
 136 /**
 137  *      saveable - Determine whether a page should be cloned or not.
 138  *      @pfn:   The page
 139  *
 140  *      We save a page if it's Reserved, and not in the range of pages
 141  *      statically defined as 'unsaveable', or if it isn't reserved, and
 142  *      isn't part of a free chunk of pages.
 143  */
 144
 145 static int saveable(struct zone *zone, unsigned long *zone_pfn)
 146 {
 147         unsigned long pfn = *zone_pfn + zone->zone_start_pfn;
 148         struct page *page;
 149
 150         if (!pfn_valid(pfn))
 151                 return 0;
 152
 153         page = pfn_to_page(pfn);
 154         BUG_ON(PageReserved(page) && PageNosave(page));
 155         if (PageNosave(page))
 156                 return 0;
 157         if (PageReserved(page) && pfn_is_nosave(pfn)) {
 158                 pr_debug("[nosave pfn 0x%lx]", pfn);
 159                 return 0;
 160         }
 161         if (PageNosaveFree(page))
 162                 return 0;
 163
 164         return 1;
 165 }
 166
 167 static unsigned count_data_pages(void)
 168 {
 169         struct zone *zone;
 170         unsigned long zone_pfn;
 171         unsigned n;
 172
 173         n = 0;
 174         for_each_zone (zone) {
 175                 if (is_highmem(zone))
 176                         continue;
 177                 mark_free_pages(zone);
 178                 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
 179                         n += saveable(zone, &zone_pfn);
 180         }
 181         return n;
 182 }
 183
 184 static void copy_data_pages(struct pbe *pblist)
 185 {
 186         struct zone *zone;
 187         unsigned long zone_pfn;
 188         struct pbe *pbe, *p;
 189
 190         pbe = pblist;
 191         for_each_zone (zone) {
 192                 if (is_highmem(zone))
 193                         continue;
 194                 mark_free_pages(zone);
 195                 /* This is necessary for swsusp_free() */
 196                 for_each_pb_page (p, pblist)
 197                         SetPageNosaveFree(virt_to_page(p));
 198                 for_each_pbe (p, pblist)
 199                         SetPageNosaveFree(virt_to_page(p->address));
 200                 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
 201                         if (saveable(zone, &zone_pfn)) {
 202                                 struct page *page;
 203                                 page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
 204                                 BUG_ON(!pbe);
 205                                 pbe->orig_address = (unsigned long)page_address(page);
 206                                 /* copy_page is not usable for copying task structs. */
 207                                 memcpy((void *)pbe->address, (void *)pbe->orig_address, PAGE_SIZE);
 208                                 pbe = pbe->next;
 209                         }
 210                 }
 211         }
 212         BUG_ON(pbe);
 213 }
 214
 215
 216 /**
 217  *      free_pagedir - free pages allocated with alloc_pagedir()
 218  */
 219
 220 static void free_pagedir(struct pbe *pblist)
 221 {
 222         struct pbe *pbe;
 223
 224         while (pblist) {
 225                 pbe = (pblist + PB_PAGE_SKIP)->next;
 226                 ClearPageNosave(virt_to_page(pblist));
 227                 ClearPageNosaveFree(virt_to_page(pblist));
 228                 free_page((unsigned long)pblist);
 229                 pblist = pbe;
 230         }
 231 }
 232
 233 /**
 234  *      fill_pb_page - Create a list of PBEs on a given memory page
 235  */
 236
 237 static inline void fill_pb_page(struct pbe *pbpage)
 238 {
 239         struct pbe *p;
 240
 241         p = pbpage;
 242         pbpage += PB_PAGE_SKIP;
 243         do
 244                 p->next = p + 1;
 245         while (++p < pbpage);
 246 }
 247
 248 /**
 249  *      create_pbe_list - Create a list of PBEs on top of a given chain
 250  *      of memory pages allocated with alloc_pagedir()
 251  */
 252
 253 void create_pbe_list(struct pbe *pblist, unsigned nr_pages)
 254 {
 255         struct pbe *pbpage, *p;
 256         unsigned num = PBES_PER_PAGE;
 257
 258         for_each_pb_page (pbpage, pblist) {
 259                 if (num >= nr_pages)
 260                         break;
 261
 262                 fill_pb_page(pbpage);
 263                 num += PBES_PER_PAGE;
 264         }
 265         if (pbpage) {
 266                 for (num -= PBES_PER_PAGE - 1, p = pbpage; num < nr_pages; p++, num++)
 267                         p->next = p + 1;
 268                 p->next = NULL;
 269         }
 270         pr_debug("create_pbe_list(): initialized %d PBEs\n", num);
 271 }
 272
 273 static void *alloc_image_page(void)
 274 {
 275         void *res = (void *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
 276         if (res) {
 277                 SetPageNosave(virt_to_page(res));
 278                 SetPageNosaveFree(virt_to_page(res));
 279         }
 280         return res;
 281 }
 282
 283 /**
 284  *      alloc_pagedir - Allocate the page directory.
 285  *
 286  *      First, determine exactly how many pages we need and
 287  *      allocate them.
 288  *
 289  *      We arrange the pages in a chain: each page is an array of PBES_PER_PAGE
 290  *      struct pbe elements (pbes) and the last element in the page points
 291  *      to the next page.
 292  *
 293  *      On each page we set up a list of struct_pbe elements.
 294  */
 295
 296 struct pbe *alloc_pagedir(unsigned nr_pages)
 297 {
 298         unsigned num;
 299         struct pbe *pblist, *pbe;
 300
 301         if (!nr_pages)
 302                 return NULL;
 303
 304         pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages);
 305         pblist = alloc_image_page();
 306         /* FIXME: rewrite this ugly loop */
 307         for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
 308                         pbe = pbe->next, num += PBES_PER_PAGE) {
 309                 pbe += PB_PAGE_SKIP;
 310                 pbe->next = alloc_image_page();
 311         }
 312         if (!pbe) { /* get_zeroed_page() failed */
 313                 free_pagedir(pblist);
 314                 pblist = NULL;
 315         }
 316         return pblist;
 317 }
 318
 319 /**
 320  * Free pages we allocated for suspend. Suspend pages are alocated
 321  * before atomic copy, so we need to free them after resume.
 322  */
 323
 324 void swsusp_free(void)
 325 {
 326         struct zone *zone;
 327         unsigned long zone_pfn;
 328
 329         for_each_zone(zone) {
 330                 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
 331                         if (pfn_valid(zone_pfn + zone->zone_start_pfn)) {
 332                                 struct page * page;
 333                                 page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
 334                                 if (PageNosave(page) && PageNosaveFree(page)) {
 335                                         ClearPageNosave(page);
 336                                         ClearPageNosaveFree(page);
 337                                         free_page((long) page_address(page));
 338                                 }
 339                         }
 340         }
 341 }
 342
 343
 344 /**
 345  *      enough_free_mem - Make sure we enough free memory to snapshot.
 346  *
 347  *      Returns TRUE or FALSE after checking the number of available
 348  *      free pages.
 349  */
 350
 351 static int enough_free_mem(unsigned nr_pages)
 352 {
 353         pr_debug("swsusp: available memory: %u pages\n", nr_free_pages());
 354         return nr_free_pages() > (nr_pages + PAGES_FOR_IO +
 355                 (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
 356 }
 357
 358
 359 static struct pbe *swsusp_alloc(unsigned nr_pages)
 360 {
 361         struct pbe *pblist, *p;
 362
 363         if (!(pblist = alloc_pagedir(nr_pages))) {
 364                 printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
 365                 return NULL;
 366         }
 367         create_pbe_list(pblist, nr_pages);
 368
 369         for_each_pbe (p, pblist) {
 370                 p->address = (unsigned long)alloc_image_page();
 371                 if (!p->address) {
 372                         printk(KERN_ERR "suspend: Allocating image pages failed.\n");
 373                         swsusp_free();
 374                         return NULL;
 375                 }
 376         }
 377
 378         return pblist;
 379 }
 380
 381 asmlinkage int swsusp_save(void)
 382 {
 383         unsigned nr_pages;
 384
 385         pr_debug("swsusp: critical section: \n");
 386         if (save_highmem()) {
 387                 printk(KERN_CRIT "swsusp: Not enough free pages for highmem\n");
 388                 restore_highmem();
 389                 return -ENOMEM;
 390         }
 391
 392         drain_local_pages();
 393         nr_pages = count_data_pages();
 394         printk("swsusp: Need to copy %u pages\n", nr_pages);
 395
 396         pr_debug("swsusp: pages needed: %u + %lu + %u, free: %u\n",
 397                  nr_pages,
 398                  (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE,
 399                  PAGES_FOR_IO, nr_free_pages());
 400
 401         /* This is needed because of the fixed size of swsusp_info */
 402         if (MAX_PBES < (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE)
 403                 return -ENOSPC;
 404
 405         if (!enough_free_mem(nr_pages)) {
 406                 printk(KERN_ERR "swsusp: Not enough free memory\n");
 407                 return -ENOMEM;
 408         }
 409
 410         if (!enough_swap(nr_pages)) {
 411                 printk(KERN_ERR "swsusp: Not enough free swap\n");
 412                 return -ENOSPC;
 413         }
 414
 415         pagedir_nosave = swsusp_alloc(nr_pages);
 416         if (!pagedir_nosave)
 417                 return -ENOMEM;
 418
 419         /* During allocating of suspend pagedir, new cold pages may appear.
 420          * Kill them.
 421          */
 422         drain_local_pages();
 423         copy_data_pages(pagedir_nosave);
 424
 425         /*
 426          * End of critical section. From now on, we can write to memory,
 427          * but we should not touch disk. This specially means we must _not_
 428          * touch swap space! Except we must write out our image of course.
 429          */
 430
 431         nr_copy_pages = nr_pages;
 432
 433         printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
 434         return 0;
 435 }