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 int save_highmem(void) 92 { 93 struct zone *zone; 94 int res = 0; 95 96 pr_debug("swsusp: Saving Highmem\n"); 97 for_each_zone (zone) { 98 if (is_highmem(zone)) 99 res = save_highmem_zone(zone); 100 if (res) 101 return res; 102 } 103 return 0; 104 } 105 106 int restore_highmem(void) 107 { 108 printk("swsusp: Restoring Highmem\n"); 109 while (highmem_copy) { 110 struct highmem_page *save = highmem_copy; 111 void *kaddr; 112 highmem_copy = save->next; 113 114 kaddr = kmap_atomic(save->page, KM_USER0); 115 memcpy(kaddr, save->data, PAGE_SIZE); 116 kunmap_atomic(kaddr, KM_USER0); 117 free_page((long) save->data); 118 kfree(save); 119 } 120 return 0; 121 } 122 #endif 123 124 static int pfn_is_nosave(unsigned long pfn) 125 { 126 unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT; 127 unsigned long nosave_end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT; 128 return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn); 129 } 130 131 /** 132 * saveable - Determine whether a page should be cloned or not. 133 * @pfn: The page 134 * 135 * We save a page if it's Reserved, and not in the range of pages 136 * statically defined as 'unsaveable', or if it isn't reserved, and 137 * isn't part of a free chunk of pages. 138 */ 139 140 static int saveable(struct zone *zone, unsigned long *zone_pfn) 141 { 142 unsigned long pfn = *zone_pfn + zone->zone_start_pfn; 143 struct page *page; 144 145 if (!pfn_valid(pfn)) 146 return 0; 147 148 page = pfn_to_page(pfn); 149 BUG_ON(PageReserved(page) && PageNosave(page)); 150 if (PageNosave(page)) 151 return 0; 152 if (PageReserved(page) && pfn_is_nosave(pfn)) { 153 pr_debug("[nosave pfn 0x%lx]", pfn); 154 return 0; 155 } 156 if (PageNosaveFree(page)) 157 return 0; 158 159 return 1; 160 } 161 162 static unsigned count_data_pages(void) 163 { 164 struct zone *zone; 165 unsigned long zone_pfn; 166 unsigned int n = 0; 167 168 for_each_zone (zone) { 169 if (is_highmem(zone)) 170 continue; 171 mark_free_pages(zone); 172 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) 173 n += saveable(zone, &zone_pfn); 174 } 175 return n; 176 } 177 178 static void copy_data_pages(struct pbe *pblist) 179 { 180 struct zone *zone; 181 unsigned long zone_pfn; 182 struct pbe *pbe, *p; 183 184 pbe = pblist; 185 for_each_zone (zone) { 186 if (is_highmem(zone)) 187 continue; 188 mark_free_pages(zone); 189 /* This is necessary for swsusp_free() */ 190 for_each_pb_page (p, pblist) 191 SetPageNosaveFree(virt_to_page(p)); 192 for_each_pbe (p, pblist) 193 SetPageNosaveFree(virt_to_page(p->address)); 194 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) { 195 if (saveable(zone, &zone_pfn)) { 196 struct page *page; 197 page = pfn_to_page(zone_pfn + zone->zone_start_pfn); 198 BUG_ON(!pbe); 199 pbe->orig_address = (unsigned long)page_address(page); 200 /* copy_page is not usable for copying task structs. */ 201 memcpy((void *)pbe->address, (void *)pbe->orig_address, PAGE_SIZE); 202 pbe = pbe->next; 203 } 204 } 205 } 206 BUG_ON(pbe); 207 } 208 209 210 /** 211 * free_pagedir - free pages allocated with alloc_pagedir() 212 */ 213 214 void free_pagedir(struct pbe *pblist) 215 { 216 struct pbe *pbe; 217 218 while (pblist) { 219 pbe = (pblist + PB_PAGE_SKIP)->next; 220 ClearPageNosave(virt_to_page(pblist)); 221 ClearPageNosaveFree(virt_to_page(pblist)); 222 free_page((unsigned long)pblist); 223 pblist = pbe; 224 } 225 } 226 227 /** 228 * fill_pb_page - Create a list of PBEs on a given memory page 229 */ 230 231 static inline void fill_pb_page(struct pbe *pbpage) 232 { 233 struct pbe *p; 234 235 p = pbpage; 236 pbpage += PB_PAGE_SKIP; 237 do 238 p->next = p + 1; 239 while (++p < pbpage); 240 } 241 242 /** 243 * create_pbe_list - Create a list of PBEs on top of a given chain 244 * of memory pages allocated with alloc_pagedir() 245 */ 246 247 void create_pbe_list(struct pbe *pblist, unsigned int nr_pages) 248 { 249 struct pbe *pbpage, *p; 250 unsigned int num = PBES_PER_PAGE; 251 252 for_each_pb_page (pbpage, pblist) { 253 if (num >= nr_pages) 254 break; 255 256 fill_pb_page(pbpage); 257 num += PBES_PER_PAGE; 258 } 259 if (pbpage) { 260 for (num -= PBES_PER_PAGE - 1, p = pbpage; num < nr_pages; p++, num++) 261 p->next = p + 1; 262 p->next = NULL; 263 } 264 pr_debug("create_pbe_list(): initialized %d PBEs\n", num); 265 } 266 267 /** 268 * @safe_needed - on resume, for storing the PBE list and the image, 269 * we can only use memory pages that do not conflict with the pages 270 * which had been used before suspend. 271 * 272 * The unsafe pages are marked with the PG_nosave_free flag 273 * 274 * Allocated but unusable (ie eaten) memory pages should be marked 275 * so that swsusp_free() can release them 276 */ 277 278 static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed) 279 { 280 void *res; 281 282 if (safe_needed) 283 do { 284 res = (void *)get_zeroed_page(gfp_mask); 285 if (res && PageNosaveFree(virt_to_page(res))) 286 /* This is for swsusp_free() */ 287 SetPageNosave(virt_to_page(res)); 288 } while (res && PageNosaveFree(virt_to_page(res))); 289 else 290 res = (void *)get_zeroed_page(gfp_mask); 291 if (res) { 292 SetPageNosave(virt_to_page(res)); 293 SetPageNosaveFree(virt_to_page(res)); 294 } 295 return res; 296 } 297 298 unsigned long get_safe_page(gfp_t gfp_mask) 299 { 300 return (unsigned long)alloc_image_page(gfp_mask, 1); 301 } 302 303 /** 304 * alloc_pagedir - Allocate the page directory. 305 * 306 * First, determine exactly how many pages we need and 307 * allocate them. 308 * 309 * We arrange the pages in a chain: each page is an array of PBES_PER_PAGE 310 * struct pbe elements (pbes) and the last element in the page points 311 * to the next page. 312 * 313 * On each page we set up a list of struct_pbe elements. 314 */ 315 316 struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask, int safe_needed) 317 { 318 unsigned int num; 319 struct pbe *pblist, *pbe; 320 321 if (!nr_pages) 322 return NULL; 323 324 pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages); 325 pblist = alloc_image_page(gfp_mask, safe_needed); 326 /* FIXME: rewrite this ugly loop */ 327 for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages; 328 pbe = pbe->next, num += PBES_PER_PAGE) { 329 pbe += PB_PAGE_SKIP; 330 pbe->next = alloc_image_page(gfp_mask, safe_needed); 331 } 332 if (!pbe) { /* get_zeroed_page() failed */ 333 free_pagedir(pblist); 334 pblist = NULL; 335 } 336 return pblist; 337 } 338 339 /** 340 * Free pages we allocated for suspend. Suspend pages are alocated 341 * before atomic copy, so we need to free them after resume. 342 */ 343 344 void swsusp_free(void) 345 { 346 struct zone *zone; 347 unsigned long zone_pfn; 348 349 for_each_zone(zone) { 350 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) 351 if (pfn_valid(zone_pfn + zone->zone_start_pfn)) { 352 struct page *page; 353 page = pfn_to_page(zone_pfn + zone->zone_start_pfn); 354 if (PageNosave(page) && PageNosaveFree(page)) { 355 ClearPageNosave(page); 356 ClearPageNosaveFree(page); 357 free_page((long) page_address(page)); 358 } 359 } 360 } 361 } 362 363 364 /** 365 * enough_free_mem - Make sure we enough free memory to snapshot. 366 * 367 * Returns TRUE or FALSE after checking the number of available 368 * free pages. 369 */ 370 371 static int enough_free_mem(unsigned int nr_pages) 372 { 373 pr_debug("swsusp: available memory: %u pages\n", nr_free_pages()); 374 return nr_free_pages() > (nr_pages + PAGES_FOR_IO + 375 (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE); 376 } 377 378 int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed) 379 { 380 struct pbe *p; 381 382 for_each_pbe (p, pblist) { 383 p->address = (unsigned long)alloc_image_page(gfp_mask, safe_needed); 384 if (!p->address) 385 return -ENOMEM; 386 } 387 return 0; 388 } 389 390 static struct pbe *swsusp_alloc(unsigned int nr_pages) 391 { 392 struct pbe *pblist; 393 394 if (!(pblist = alloc_pagedir(nr_pages, GFP_ATOMIC | __GFP_COLD, 0))) { 395 printk(KERN_ERR "suspend: Allocating pagedir failed.\n"); 396 return NULL; 397 } 398 create_pbe_list(pblist, nr_pages); 399 400 if (alloc_data_pages(pblist, GFP_ATOMIC | __GFP_COLD, 0)) { 401 printk(KERN_ERR "suspend: Allocating image pages failed.\n"); 402 swsusp_free(); 403 return NULL; 404 } 405 406 return pblist; 407 } 408 409 asmlinkage int swsusp_save(void) 410 { 411 unsigned int nr_pages; 412 413 pr_debug("swsusp: critical section: \n"); 414 415 drain_local_pages(); 416 nr_pages = count_data_pages(); 417 printk("swsusp: Need to copy %u pages\n", nr_pages); 418 419 pr_debug("swsusp: pages needed: %u + %lu + %u, free: %u\n", 420 nr_pages, 421 (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE, 422 PAGES_FOR_IO, nr_free_pages()); 423 424 /* This is needed because of the fixed size of swsusp_info */ 425 if (MAX_PBES < (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE) 426 return -ENOSPC; 427 428 if (!enough_free_mem(nr_pages)) { 429 printk(KERN_ERR "swsusp: Not enough free memory\n"); 430 return -ENOMEM; 431 } 432 433 pagedir_nosave = swsusp_alloc(nr_pages); 434 if (!pagedir_nosave) 435 return -ENOMEM; 436 437 /* During allocating of suspend pagedir, new cold pages may appear. 438 * Kill them. 439 */ 440 drain_local_pages(); 441 copy_data_pages(pagedir_nosave); 442 443 /* 444 * End of critical section. From now on, we can write to memory, 445 * but we should not touch disk. This specially means we must _not_ 446 * touch swap space! Except we must write out our image of course. 447 */ 448 449 nr_copy_pages = nr_pages; 450 451 printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages); 452 return 0; 453 } 454