linux/kernel/kexec.c
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   1/*
   2 * kexec.c - kexec system call
   3 * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
   4 *
   5 * This source code is licensed under the GNU General Public License,
   6 * Version 2.  See the file COPYING for more details.
   7 */
   8
   9#include <linux/capability.h>
  10#include <linux/mm.h>
  11#include <linux/file.h>
  12#include <linux/slab.h>
  13#include <linux/fs.h>
  14#include <linux/kexec.h>
  15#include <linux/mutex.h>
  16#include <linux/list.h>
  17#include <linux/highmem.h>
  18#include <linux/syscalls.h>
  19#include <linux/reboot.h>
  20#include <linux/ioport.h>
  21#include <linux/hardirq.h>
  22#include <linux/elf.h>
  23#include <linux/elfcore.h>
  24#include <linux/utsname.h>
  25#include <linux/numa.h>
  26#include <linux/suspend.h>
  27#include <linux/device.h>
  28#include <linux/freezer.h>
  29#include <linux/pm.h>
  30#include <linux/cpu.h>
  31#include <linux/console.h>
  32#include <linux/vmalloc.h>
  33#include <linux/swap.h>
  34#include <linux/syscore_ops.h>
  35
  36#include <asm/page.h>
  37#include <asm/uaccess.h>
  38#include <asm/io.h>
  39#include <asm/sections.h>
  40
  41/* Per cpu memory for storing cpu states in case of system crash. */
  42note_buf_t __percpu *crash_notes;
  43
  44/* vmcoreinfo stuff */
  45static unsigned char vmcoreinfo_data[VMCOREINFO_BYTES];
  46u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
  47size_t vmcoreinfo_size;
  48size_t vmcoreinfo_max_size = sizeof(vmcoreinfo_data);
  49
  50/* Location of the reserved area for the crash kernel */
  51struct resource crashk_res = {
  52        .name  = "Crash kernel",
  53        .start = 0,
  54        .end   = 0,
  55        .flags = IORESOURCE_BUSY | IORESOURCE_MEM
  56};
  57struct resource crashk_low_res = {
  58        .name  = "Crash kernel",
  59        .start = 0,
  60        .end   = 0,
  61        .flags = IORESOURCE_BUSY | IORESOURCE_MEM
  62};
  63
  64int kexec_should_crash(struct task_struct *p)
  65{
  66        if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
  67                return 1;
  68        return 0;
  69}
  70
  71/*
  72 * When kexec transitions to the new kernel there is a one-to-one
  73 * mapping between physical and virtual addresses.  On processors
  74 * where you can disable the MMU this is trivial, and easy.  For
  75 * others it is still a simple predictable page table to setup.
  76 *
  77 * In that environment kexec copies the new kernel to its final
  78 * resting place.  This means I can only support memory whose
  79 * physical address can fit in an unsigned long.  In particular
  80 * addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
  81 * If the assembly stub has more restrictive requirements
  82 * KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
  83 * defined more restrictively in <asm/kexec.h>.
  84 *
  85 * The code for the transition from the current kernel to the
  86 * the new kernel is placed in the control_code_buffer, whose size
  87 * is given by KEXEC_CONTROL_PAGE_SIZE.  In the best case only a single
  88 * page of memory is necessary, but some architectures require more.
  89 * Because this memory must be identity mapped in the transition from
  90 * virtual to physical addresses it must live in the range
  91 * 0 - TASK_SIZE, as only the user space mappings are arbitrarily
  92 * modifiable.
  93 *
  94 * The assembly stub in the control code buffer is passed a linked list
  95 * of descriptor pages detailing the source pages of the new kernel,
  96 * and the destination addresses of those source pages.  As this data
  97 * structure is not used in the context of the current OS, it must
  98 * be self-contained.
  99 *
 100 * The code has been made to work with highmem pages and will use a
 101 * destination page in its final resting place (if it happens
 102 * to allocate it).  The end product of this is that most of the
 103 * physical address space, and most of RAM can be used.
 104 *
 105 * Future directions include:
 106 *  - allocating a page table with the control code buffer identity
 107 *    mapped, to simplify machine_kexec and make kexec_on_panic more
 108 *    reliable.
 109 */
 110
 111/*
 112 * KIMAGE_NO_DEST is an impossible destination address..., for
 113 * allocating pages whose destination address we do not care about.
 114 */
 115#define KIMAGE_NO_DEST (-1UL)
 116
 117static int kimage_is_destination_range(struct kimage *image,
 118                                       unsigned long start, unsigned long end);
 119static struct page *kimage_alloc_page(struct kimage *image,
 120                                       gfp_t gfp_mask,
 121                                       unsigned long dest);
 122
 123static int do_kimage_alloc(struct kimage **rimage, unsigned long entry,
 124                            unsigned long nr_segments,
 125                            struct kexec_segment __user *segments)
 126{
 127        size_t segment_bytes;
 128        struct kimage *image;
 129        unsigned long i;
 130        int result;
 131
 132        /* Allocate a controlling structure */
 133        result = -ENOMEM;
 134        image = kzalloc(sizeof(*image), GFP_KERNEL);
 135        if (!image)
 136                goto out;
 137
 138        image->head = 0;
 139        image->entry = &image->head;
 140        image->last_entry = &image->head;
 141        image->control_page = ~0; /* By default this does not apply */
 142        image->start = entry;
 143        image->type = KEXEC_TYPE_DEFAULT;
 144
 145        /* Initialize the list of control pages */
 146        INIT_LIST_HEAD(&image->control_pages);
 147
 148        /* Initialize the list of destination pages */
 149        INIT_LIST_HEAD(&image->dest_pages);
 150
 151        /* Initialize the list of unusable pages */
 152        INIT_LIST_HEAD(&image->unuseable_pages);
 153
 154        /* Read in the segments */
 155        image->nr_segments = nr_segments;
 156        segment_bytes = nr_segments * sizeof(*segments);
 157        result = copy_from_user(image->segment, segments, segment_bytes);
 158        if (result) {
 159                result = -EFAULT;
 160                goto out;
 161        }
 162
 163        /*
 164         * Verify we have good destination addresses.  The caller is
 165         * responsible for making certain we don't attempt to load
 166         * the new image into invalid or reserved areas of RAM.  This
 167         * just verifies it is an address we can use.
 168         *
 169         * Since the kernel does everything in page size chunks ensure
 170         * the destination addresses are page aligned.  Too many
 171         * special cases crop of when we don't do this.  The most
 172         * insidious is getting overlapping destination addresses
 173         * simply because addresses are changed to page size
 174         * granularity.
 175         */
 176        result = -EADDRNOTAVAIL;
 177        for (i = 0; i < nr_segments; i++) {
 178                unsigned long mstart, mend;
 179
 180                mstart = image->segment[i].mem;
 181                mend   = mstart + image->segment[i].memsz;
 182                if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
 183                        goto out;
 184                if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
 185                        goto out;
 186        }
 187
 188        /* Verify our destination addresses do not overlap.
 189         * If we alloed overlapping destination addresses
 190         * through very weird things can happen with no
 191         * easy explanation as one segment stops on another.
 192         */
 193        result = -EINVAL;
 194        for (i = 0; i < nr_segments; i++) {
 195                unsigned long mstart, mend;
 196                unsigned long j;
 197
 198                mstart = image->segment[i].mem;
 199                mend   = mstart + image->segment[i].memsz;
 200                for (j = 0; j < i; j++) {
 201                        unsigned long pstart, pend;
 202                        pstart = image->segment[j].mem;
 203                        pend   = pstart + image->segment[j].memsz;
 204                        /* Do the segments overlap ? */
 205                        if ((mend > pstart) && (mstart < pend))
 206                                goto out;
 207                }
 208        }
 209
 210        /* Ensure our buffer sizes are strictly less than
 211         * our memory sizes.  This should always be the case,
 212         * and it is easier to check up front than to be surprised
 213         * later on.
 214         */
 215        result = -EINVAL;
 216        for (i = 0; i < nr_segments; i++) {
 217                if (image->segment[i].bufsz > image->segment[i].memsz)
 218                        goto out;
 219        }
 220
 221        result = 0;
 222out:
 223        if (result == 0)
 224                *rimage = image;
 225        else
 226                kfree(image);
 227
 228        return result;
 229
 230}
 231
 232static void kimage_free_page_list(struct list_head *list);
 233
 234static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
 235                                unsigned long nr_segments,
 236                                struct kexec_segment __user *segments)
 237{
 238        int result;
 239        struct kimage *image;
 240
 241        /* Allocate and initialize a controlling structure */
 242        image = NULL;
 243        result = do_kimage_alloc(&image, entry, nr_segments, segments);
 244        if (result)
 245                goto out;
 246
 247        /*
 248         * Find a location for the control code buffer, and add it
 249         * the vector of segments so that it's pages will also be
 250         * counted as destination pages.
 251         */
 252        result = -ENOMEM;
 253        image->control_code_page = kimage_alloc_control_pages(image,
 254                                           get_order(KEXEC_CONTROL_PAGE_SIZE));
 255        if (!image->control_code_page) {
 256                printk(KERN_ERR "Could not allocate control_code_buffer\n");
 257                goto out_free;
 258        }
 259
 260        image->swap_page = kimage_alloc_control_pages(image, 0);
 261        if (!image->swap_page) {
 262                printk(KERN_ERR "Could not allocate swap buffer\n");
 263                goto out_free;
 264        }
 265
 266        *rimage = image;
 267        return 0;
 268
 269out_free:
 270        kimage_free_page_list(&image->control_pages);
 271        kfree(image);
 272out:
 273        return result;
 274}
 275
 276static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry,
 277                                unsigned long nr_segments,
 278                                struct kexec_segment __user *segments)
 279{
 280        int result;
 281        struct kimage *image;
 282        unsigned long i;
 283
 284        image = NULL;
 285        /* Verify we have a valid entry point */
 286        if ((entry < crashk_res.start) || (entry > crashk_res.end)) {
 287                result = -EADDRNOTAVAIL;
 288                goto out;
 289        }
 290
 291        /* Allocate and initialize a controlling structure */
 292        result = do_kimage_alloc(&image, entry, nr_segments, segments);
 293        if (result)
 294                goto out;
 295
 296        /* Enable the special crash kernel control page
 297         * allocation policy.
 298         */
 299        image->control_page = crashk_res.start;
 300        image->type = KEXEC_TYPE_CRASH;
 301
 302        /*
 303         * Verify we have good destination addresses.  Normally
 304         * the caller is responsible for making certain we don't
 305         * attempt to load the new image into invalid or reserved
 306         * areas of RAM.  But crash kernels are preloaded into a
 307         * reserved area of ram.  We must ensure the addresses
 308         * are in the reserved area otherwise preloading the
 309         * kernel could corrupt things.
 310         */
 311        result = -EADDRNOTAVAIL;
 312        for (i = 0; i < nr_segments; i++) {
 313                unsigned long mstart, mend;
 314
 315                mstart = image->segment[i].mem;
 316                mend = mstart + image->segment[i].memsz - 1;
 317                /* Ensure we are within the crash kernel limits */
 318                if ((mstart < crashk_res.start) || (mend > crashk_res.end))
 319                        goto out_free;
 320        }
 321
 322        /*
 323         * Find a location for the control code buffer, and add
 324         * the vector of segments so that it's pages will also be
 325         * counted as destination pages.
 326         */
 327        result = -ENOMEM;
 328        image->control_code_page = kimage_alloc_control_pages(image,
 329                                           get_order(KEXEC_CONTROL_PAGE_SIZE));
 330        if (!image->control_code_page) {
 331                printk(KERN_ERR "Could not allocate control_code_buffer\n");
 332                goto out_free;
 333        }
 334
 335        *rimage = image;
 336        return 0;
 337
 338out_free:
 339        kfree(image);
 340out:
 341        return result;
 342}
 343
 344static int kimage_is_destination_range(struct kimage *image,
 345                                        unsigned long start,
 346                                        unsigned long end)
 347{
 348        unsigned long i;
 349
 350        for (i = 0; i < image->nr_segments; i++) {
 351                unsigned long mstart, mend;
 352
 353                mstart = image->segment[i].mem;
 354                mend = mstart + image->segment[i].memsz;
 355                if ((end > mstart) && (start < mend))
 356                        return 1;
 357        }
 358
 359        return 0;
 360}
 361
 362static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
 363{
 364        struct page *pages;
 365
 366        pages = alloc_pages(gfp_mask, order);
 367        if (pages) {
 368                unsigned int count, i;
 369                pages->mapping = NULL;
 370                set_page_private(pages, order);
 371                count = 1 << order;
 372                for (i = 0; i < count; i++)
 373                        SetPageReserved(pages + i);
 374        }
 375
 376        return pages;
 377}
 378
 379static void kimage_free_pages(struct page *page)
 380{
 381        unsigned int order, count, i;
 382
 383        order = page_private(page);
 384        count = 1 << order;
 385        for (i = 0; i < count; i++)
 386                ClearPageReserved(page + i);
 387        __free_pages(page, order);
 388}
 389
 390static void kimage_free_page_list(struct list_head *list)
 391{
 392        struct list_head *pos, *next;
 393
 394        list_for_each_safe(pos, next, list) {
 395                struct page *page;
 396
 397                page = list_entry(pos, struct page, lru);
 398                list_del(&page->lru);
 399                kimage_free_pages(page);
 400        }
 401}
 402
 403static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
 404                                                        unsigned int order)
 405{
 406        /* Control pages are special, they are the intermediaries
 407         * that are needed while we copy the rest of the pages
 408         * to their final resting place.  As such they must
 409         * not conflict with either the destination addresses
 410         * or memory the kernel is already using.
 411         *
 412         * The only case where we really need more than one of
 413         * these are for architectures where we cannot disable
 414         * the MMU and must instead generate an identity mapped
 415         * page table for all of the memory.
 416         *
 417         * At worst this runs in O(N) of the image size.
 418         */
 419        struct list_head extra_pages;
 420        struct page *pages;
 421        unsigned int count;
 422
 423        count = 1 << order;
 424        INIT_LIST_HEAD(&extra_pages);
 425
 426        /* Loop while I can allocate a page and the page allocated
 427         * is a destination page.
 428         */
 429        do {
 430                unsigned long pfn, epfn, addr, eaddr;
 431
 432                pages = kimage_alloc_pages(GFP_KERNEL, order);
 433                if (!pages)
 434                        break;
 435                pfn   = page_to_pfn(pages);
 436                epfn  = pfn + count;
 437                addr  = pfn << PAGE_SHIFT;
 438                eaddr = epfn << PAGE_SHIFT;
 439                if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
 440                              kimage_is_destination_range(image, addr, eaddr)) {
 441                        list_add(&pages->lru, &extra_pages);
 442                        pages = NULL;
 443                }
 444        } while (!pages);
 445
 446        if (pages) {
 447                /* Remember the allocated page... */
 448                list_add(&pages->lru, &image->control_pages);
 449
 450                /* Because the page is already in it's destination
 451                 * location we will never allocate another page at
 452                 * that address.  Therefore kimage_alloc_pages
 453                 * will not return it (again) and we don't need
 454                 * to give it an entry in image->segment[].
 455                 */
 456        }
 457        /* Deal with the destination pages I have inadvertently allocated.
 458         *
 459         * Ideally I would convert multi-page allocations into single
 460         * page allocations, and add everything to image->dest_pages.
 461         *
 462         * For now it is simpler to just free the pages.
 463         */
 464        kimage_free_page_list(&extra_pages);
 465
 466        return pages;
 467}
 468
 469static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
 470                                                      unsigned int order)
 471{
 472        /* Control pages are special, they are the intermediaries
 473         * that are needed while we copy the rest of the pages
 474         * to their final resting place.  As such they must
 475         * not conflict with either the destination addresses
 476         * or memory the kernel is already using.
 477         *
 478         * Control pages are also the only pags we must allocate
 479         * when loading a crash kernel.  All of the other pages
 480         * are specified by the segments and we just memcpy
 481         * into them directly.
 482         *
 483         * The only case where we really need more than one of
 484         * these are for architectures where we cannot disable
 485         * the MMU and must instead generate an identity mapped
 486         * page table for all of the memory.
 487         *
 488         * Given the low demand this implements a very simple
 489         * allocator that finds the first hole of the appropriate
 490         * size in the reserved memory region, and allocates all
 491         * of the memory up to and including the hole.
 492         */
 493        unsigned long hole_start, hole_end, size;
 494        struct page *pages;
 495
 496        pages = NULL;
 497        size = (1 << order) << PAGE_SHIFT;
 498        hole_start = (image->control_page + (size - 1)) & ~(size - 1);
 499        hole_end   = hole_start + size - 1;
 500        while (hole_end <= crashk_res.end) {
 501                unsigned long i;
 502
 503                if (hole_end > KEXEC_CRASH_CONTROL_MEMORY_LIMIT)
 504                        break;
 505                /* See if I overlap any of the segments */
 506                for (i = 0; i < image->nr_segments; i++) {
 507                        unsigned long mstart, mend;
 508
 509                        mstart = image->segment[i].mem;
 510                        mend   = mstart + image->segment[i].memsz - 1;
 511                        if ((hole_end >= mstart) && (hole_start <= mend)) {
 512                                /* Advance the hole to the end of the segment */
 513                                hole_start = (mend + (size - 1)) & ~(size - 1);
 514                                hole_end   = hole_start + size - 1;
 515                                break;
 516                        }
 517                }
 518                /* If I don't overlap any segments I have found my hole! */
 519                if (i == image->nr_segments) {
 520                        pages = pfn_to_page(hole_start >> PAGE_SHIFT);
 521                        break;
 522                }
 523        }
 524        if (pages)
 525                image->control_page = hole_end;
 526
 527        return pages;
 528}
 529
 530
 531struct page *kimage_alloc_control_pages(struct kimage *image,
 532                                         unsigned int order)
 533{
 534        struct page *pages = NULL;
 535
 536        switch (image->type) {
 537        case KEXEC_TYPE_DEFAULT:
 538                pages = kimage_alloc_normal_control_pages(image, order);
 539                break;
 540        case KEXEC_TYPE_CRASH:
 541                pages = kimage_alloc_crash_control_pages(image, order);
 542                break;
 543        }
 544
 545        return pages;
 546}
 547
 548static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
 549{
 550        if (*image->entry != 0)
 551                image->entry++;
 552
 553        if (image->entry == image->last_entry) {
 554                kimage_entry_t *ind_page;
 555                struct page *page;
 556
 557                page = kimage_alloc_page(image, GFP_KERNEL, KIMAGE_NO_DEST);
 558                if (!page)
 559                        return -ENOMEM;
 560
 561                ind_page = page_address(page);
 562                *image->entry = virt_to_phys(ind_page) | IND_INDIRECTION;
 563                image->entry = ind_page;
 564                image->last_entry = ind_page +
 565                                      ((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
 566        }
 567        *image->entry = entry;
 568        image->entry++;
 569        *image->entry = 0;
 570
 571        return 0;
 572}
 573
 574static int kimage_set_destination(struct kimage *image,
 575                                   unsigned long destination)
 576{
 577        int result;
 578
 579        destination &= PAGE_MASK;
 580        result = kimage_add_entry(image, destination | IND_DESTINATION);
 581        if (result == 0)
 582                image->destination = destination;
 583
 584        return result;
 585}
 586
 587
 588static int kimage_add_page(struct kimage *image, unsigned long page)
 589{
 590        int result;
 591
 592        page &= PAGE_MASK;
 593        result = kimage_add_entry(image, page | IND_SOURCE);
 594        if (result == 0)
 595                image->destination += PAGE_SIZE;
 596
 597        return result;
 598}
 599
 600
 601static void kimage_free_extra_pages(struct kimage *image)
 602{
 603        /* Walk through and free any extra destination pages I may have */
 604        kimage_free_page_list(&image->dest_pages);
 605
 606        /* Walk through and free any unusable pages I have cached */
 607        kimage_free_page_list(&image->unuseable_pages);
 608
 609}
 610static void kimage_terminate(struct kimage *image)
 611{
 612        if (*image->entry != 0)
 613                image->entry++;
 614
 615        *image->entry = IND_DONE;
 616}
 617
 618#define for_each_kimage_entry(image, ptr, entry) \
 619        for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
 620                ptr = (entry & IND_INDIRECTION)? \
 621                        phys_to_virt((entry & PAGE_MASK)): ptr +1)
 622
 623static void kimage_free_entry(kimage_entry_t entry)
 624{
 625        struct page *page;
 626
 627        page = pfn_to_page(entry >> PAGE_SHIFT);
 628        kimage_free_pages(page);
 629}
 630
 631static void kimage_free(struct kimage *image)
 632{
 633        kimage_entry_t *ptr, entry;
 634        kimage_entry_t ind = 0;
 635
 636        if (!image)
 637                return;
 638
 639        kimage_free_extra_pages(image);
 640        for_each_kimage_entry(image, ptr, entry) {
 641                if (entry & IND_INDIRECTION) {
 642                        /* Free the previous indirection page */
 643                        if (ind & IND_INDIRECTION)
 644                                kimage_free_entry(ind);
 645                        /* Save this indirection page until we are
 646                         * done with it.
 647                         */
 648                        ind = entry;
 649                }
 650                else if (entry & IND_SOURCE)
 651                        kimage_free_entry(entry);
 652        }
 653        /* Free the final indirection page */
 654        if (ind & IND_INDIRECTION)
 655                kimage_free_entry(ind);
 656
 657        /* Handle any machine specific cleanup */
 658        machine_kexec_cleanup(image);
 659
 660        /* Free the kexec control pages... */
 661        kimage_free_page_list(&image->control_pages);
 662        kfree(image);
 663}
 664
 665static kimage_entry_t *kimage_dst_used(struct kimage *image,
 666                                        unsigned long page)
 667{
 668        kimage_entry_t *ptr, entry;
 669        unsigned long destination = 0;
 670
 671        for_each_kimage_entry(image, ptr, entry) {
 672                if (entry & IND_DESTINATION)
 673                        destination = entry & PAGE_MASK;
 674                else if (entry & IND_SOURCE) {
 675                        if (page == destination)
 676                                return ptr;
 677                        destination += PAGE_SIZE;
 678                }
 679        }
 680
 681        return NULL;
 682}
 683
 684static struct page *kimage_alloc_page(struct kimage *image,
 685                                        gfp_t gfp_mask,
 686                                        unsigned long destination)
 687{
 688        /*
 689         * Here we implement safeguards to ensure that a source page
 690         * is not copied to its destination page before the data on
 691         * the destination page is no longer useful.
 692         *
 693         * To do this we maintain the invariant that a source page is
 694         * either its own destination page, or it is not a
 695         * destination page at all.
 696         *
 697         * That is slightly stronger than required, but the proof
 698         * that no problems will not occur is trivial, and the
 699         * implementation is simply to verify.
 700         *
 701         * When allocating all pages normally this algorithm will run
 702         * in O(N) time, but in the worst case it will run in O(N^2)
 703         * time.   If the runtime is a problem the data structures can
 704         * be fixed.
 705         */
 706        struct page *page;
 707        unsigned long addr;
 708
 709        /*
 710         * Walk through the list of destination pages, and see if I
 711         * have a match.
 712         */
 713        list_for_each_entry(page, &image->dest_pages, lru) {
 714                addr = page_to_pfn(page) << PAGE_SHIFT;
 715                if (addr == destination) {
 716                        list_del(&page->lru);
 717                        return page;
 718                }
 719        }
 720        page = NULL;
 721        while (1) {
 722                kimage_entry_t *old;
 723
 724                /* Allocate a page, if we run out of memory give up */
 725                page = kimage_alloc_pages(gfp_mask, 0);
 726                if (!page)
 727                        return NULL;
 728                /* If the page cannot be used file it away */
 729                if (page_to_pfn(page) >
 730                                (KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
 731                        list_add(&page->lru, &image->unuseable_pages);
 732                        continue;
 733                }
 734                addr = page_to_pfn(page) << PAGE_SHIFT;
 735
 736                /* If it is the destination page we want use it */
 737                if (addr == destination)
 738                        break;
 739
 740                /* If the page is not a destination page use it */
 741                if (!kimage_is_destination_range(image, addr,
 742                                                  addr + PAGE_SIZE))
 743                        break;
 744
 745                /*
 746                 * I know that the page is someones destination page.
 747                 * See if there is already a source page for this
 748                 * destination page.  And if so swap the source pages.
 749                 */
 750                old = kimage_dst_used(image, addr);
 751                if (old) {
 752                        /* If so move it */
 753                        unsigned long old_addr;
 754                        struct page *old_page;
 755
 756                        old_addr = *old & PAGE_MASK;
 757                        old_page = pfn_to_page(old_addr >> PAGE_SHIFT);
 758                        copy_highpage(page, old_page);
 759                        *old = addr | (*old & ~PAGE_MASK);
 760
 761                        /* The old page I have found cannot be a
 762                         * destination page, so return it if it's
 763                         * gfp_flags honor the ones passed in.
 764                         */
 765                        if (!(gfp_mask & __GFP_HIGHMEM) &&
 766                            PageHighMem(old_page)) {
 767                                kimage_free_pages(old_page);
 768                                continue;
 769                        }
 770                        addr = old_addr;
 771                        page = old_page;
 772                        break;
 773                }
 774                else {
 775                        /* Place the page on the destination list I
 776                         * will use it later.
 777                         */
 778                        list_add(&page->lru, &image->dest_pages);
 779                }
 780        }
 781
 782        return page;
 783}
 784
 785static int kimage_load_normal_segment(struct kimage *image,
 786                                         struct kexec_segment *segment)
 787{
 788        unsigned long maddr;
 789        unsigned long ubytes, mbytes;
 790        int result;
 791        unsigned char __user *buf;
 792
 793        result = 0;
 794        buf = segment->buf;
 795        ubytes = segment->bufsz;
 796        mbytes = segment->memsz;
 797        maddr = segment->mem;
 798
 799        result = kimage_set_destination(image, maddr);
 800        if (result < 0)
 801                goto out;
 802
 803        while (mbytes) {
 804                struct page *page;
 805                char *ptr;
 806                size_t uchunk, mchunk;
 807
 808                page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
 809                if (!page) {
 810                        result  = -ENOMEM;
 811                        goto out;
 812                }
 813                result = kimage_add_page(image, page_to_pfn(page)
 814                                                                << PAGE_SHIFT);
 815                if (result < 0)
 816                        goto out;
 817
 818                ptr = kmap(page);
 819                /* Start with a clear page */
 820                clear_page(ptr);
 821                ptr += maddr & ~PAGE_MASK;
 822                mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
 823                if (mchunk > mbytes)
 824                        mchunk = mbytes;
 825
 826                uchunk = mchunk;
 827                if (uchunk > ubytes)
 828                        uchunk = ubytes;
 829
 830                result = copy_from_user(ptr, buf, uchunk);
 831                kunmap(page);
 832                if (result) {
 833                        result = -EFAULT;
 834                        goto out;
 835                }
 836                ubytes -= uchunk;
 837                maddr  += mchunk;
 838                buf    += mchunk;
 839                mbytes -= mchunk;
 840        }
 841out:
 842        return result;
 843}
 844
 845static int kimage_load_crash_segment(struct kimage *image,
 846                                        struct kexec_segment *segment)
 847{
 848        /* For crash dumps kernels we simply copy the data from
 849         * user space to it's destination.
 850         * We do things a page at a time for the sake of kmap.
 851         */
 852        unsigned long maddr;
 853        unsigned long ubytes, mbytes;
 854        int result;
 855        unsigned char __user *buf;
 856
 857        result = 0;
 858        buf = segment->buf;
 859        ubytes = segment->bufsz;
 860        mbytes = segment->memsz;
 861        maddr = segment->mem;
 862        while (mbytes) {
 863                struct page *page;
 864                char *ptr;
 865                size_t uchunk, mchunk;
 866
 867                page = pfn_to_page(maddr >> PAGE_SHIFT);
 868                if (!page) {
 869                        result  = -ENOMEM;
 870                        goto out;
 871                }
 872                ptr = kmap(page);
 873                ptr += maddr & ~PAGE_MASK;
 874                mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
 875                if (mchunk > mbytes)
 876                        mchunk = mbytes;
 877
 878                uchunk = mchunk;
 879                if (uchunk > ubytes) {
 880                        uchunk = ubytes;
 881                        /* Zero the trailing part of the page */
 882                        memset(ptr + uchunk, 0, mchunk - uchunk);
 883                }
 884                result = copy_from_user(ptr, buf, uchunk);
 885                kexec_flush_icache_page(page);
 886                kunmap(page);
 887                if (result) {
 888                        result = -EFAULT;
 889                        goto out;
 890                }
 891                ubytes -= uchunk;
 892                maddr  += mchunk;
 893                buf    += mchunk;
 894                mbytes -= mchunk;
 895        }
 896out:
 897        return result;
 898}
 899
 900static int kimage_load_segment(struct kimage *image,
 901                                struct kexec_segment *segment)
 902{
 903        int result = -ENOMEM;
 904
 905        switch (image->type) {
 906        case KEXEC_TYPE_DEFAULT:
 907                result = kimage_load_normal_segment(image, segment);
 908                break;
 909        case KEXEC_TYPE_CRASH:
 910                result = kimage_load_crash_segment(image, segment);
 911                break;
 912        }
 913
 914        return result;
 915}
 916
 917/*
 918 * Exec Kernel system call: for obvious reasons only root may call it.
 919 *
 920 * This call breaks up into three pieces.
 921 * - A generic part which loads the new kernel from the current
 922 *   address space, and very carefully places the data in the
 923 *   allocated pages.
 924 *
 925 * - A generic part that interacts with the kernel and tells all of
 926 *   the devices to shut down.  Preventing on-going dmas, and placing
 927 *   the devices in a consistent state so a later kernel can
 928 *   reinitialize them.
 929 *
 930 * - A machine specific part that includes the syscall number
 931 *   and the copies the image to it's final destination.  And
 932 *   jumps into the image at entry.
 933 *
 934 * kexec does not sync, or unmount filesystems so if you need
 935 * that to happen you need to do that yourself.
 936 */
 937struct kimage *kexec_image;
 938struct kimage *kexec_crash_image;
 939
 940static DEFINE_MUTEX(kexec_mutex);
 941
 942SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
 943                struct kexec_segment __user *, segments, unsigned long, flags)
 944{
 945        struct kimage **dest_image, *image;
 946        int result;
 947
 948        /* We only trust the superuser with rebooting the system. */
 949        if (!capable(CAP_SYS_BOOT))
 950                return -EPERM;
 951
 952        /*
 953         * Verify we have a legal set of flags
 954         * This leaves us room for future extensions.
 955         */
 956        if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
 957                return -EINVAL;
 958
 959        /* Verify we are on the appropriate architecture */
 960        if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
 961                ((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
 962                return -EINVAL;
 963
 964        /* Put an artificial cap on the number
 965         * of segments passed to kexec_load.
 966         */
 967        if (nr_segments > KEXEC_SEGMENT_MAX)
 968                return -EINVAL;
 969
 970        image = NULL;
 971        result = 0;
 972
 973        /* Because we write directly to the reserved memory
 974         * region when loading crash kernels we need a mutex here to
 975         * prevent multiple crash  kernels from attempting to load
 976         * simultaneously, and to prevent a crash kernel from loading
 977         * over the top of a in use crash kernel.
 978         *
 979         * KISS: always take the mutex.
 980         */
 981        if (!mutex_trylock(&kexec_mutex))
 982                return -EBUSY;
 983
 984        dest_image = &kexec_image;
 985        if (flags & KEXEC_ON_CRASH)
 986                dest_image = &kexec_crash_image;
 987        if (nr_segments > 0) {
 988                unsigned long i;
 989
 990                /* Loading another kernel to reboot into */
 991                if ((flags & KEXEC_ON_CRASH) == 0)
 992                        result = kimage_normal_alloc(&image, entry,
 993                                                        nr_segments, segments);
 994                /* Loading another kernel to switch to if this one crashes */
 995                else if (flags & KEXEC_ON_CRASH) {
 996                        /* Free any current crash dump kernel before
 997                         * we corrupt it.
 998                         */
 999                        kimage_free(xchg(&kexec_crash_image, NULL));
1000                        result = kimage_crash_alloc(&image, entry,
1001                                                     nr_segments, segments);
1002                        crash_map_reserved_pages();
1003                }
1004                if (result)
1005                        goto out;
1006
1007                if (flags & KEXEC_PRESERVE_CONTEXT)
1008                        image->preserve_context = 1;
1009                result = machine_kexec_prepare(image);
1010                if (result)
1011                        goto out;
1012
1013                for (i = 0; i < nr_segments; i++) {
1014                        result = kimage_load_segment(image, &image->segment[i]);
1015                        if (result)
1016                                goto out;
1017                }
1018                kimage_terminate(image);
1019                if (flags & KEXEC_ON_CRASH)
1020                        crash_unmap_reserved_pages();
1021        }
1022        /* Install the new kernel, and  Uninstall the old */
1023        image = xchg(dest_image, image);
1024
1025out:
1026        mutex_unlock(&kexec_mutex);
1027        kimage_free(image);
1028
1029        return result;
1030}
1031
1032/*
1033 * Add and remove page tables for crashkernel memory
1034 *
1035 * Provide an empty default implementation here -- architecture
1036 * code may override this
1037 */
1038void __weak crash_map_reserved_pages(void)
1039{}
1040
1041void __weak crash_unmap_reserved_pages(void)
1042{}
1043
1044#ifdef CONFIG_COMPAT
1045asmlinkage long compat_sys_kexec_load(unsigned long entry,
1046                                unsigned long nr_segments,
1047                                struct compat_kexec_segment __user *segments,
1048                                unsigned long flags)
1049{
1050        struct compat_kexec_segment in;
1051        struct kexec_segment out, __user *ksegments;
1052        unsigned long i, result;
1053
1054        /* Don't allow clients that don't understand the native
1055         * architecture to do anything.
1056         */
1057        if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
1058                return -EINVAL;
1059
1060        if (nr_segments > KEXEC_SEGMENT_MAX)
1061                return -EINVAL;
1062
1063        ksegments = compat_alloc_user_space(nr_segments * sizeof(out));
1064        for (i=0; i < nr_segments; i++) {
1065                result = copy_from_user(&in, &segments[i], sizeof(in));
1066                if (result)
1067                        return -EFAULT;
1068
1069                out.buf   = compat_ptr(in.buf);
1070                out.bufsz = in.bufsz;
1071                out.mem   = in.mem;
1072                out.memsz = in.memsz;
1073
1074                result = copy_to_user(&ksegments[i], &out, sizeof(out));
1075                if (result)
1076                        return -EFAULT;
1077        }
1078
1079        return sys_kexec_load(entry, nr_segments, ksegments, flags);
1080}
1081#endif
1082
1083void crash_kexec(struct pt_regs *regs)
1084{
1085        /* Take the kexec_mutex here to prevent sys_kexec_load
1086         * running on one cpu from replacing the crash kernel
1087         * we are using after a panic on a different cpu.
1088         *
1089         * If the crash kernel was not located in a fixed area
1090         * of memory the xchg(&kexec_crash_image) would be
1091         * sufficient.  But since I reuse the memory...
1092         */
1093        if (mutex_trylock(&kexec_mutex)) {
1094                if (kexec_crash_image) {
1095                        struct pt_regs fixed_regs;
1096
1097                        crash_setup_regs(&fixed_regs, regs);
1098                        crash_save_vmcoreinfo();
1099                        machine_crash_shutdown(&fixed_regs);
1100                        machine_kexec(kexec_crash_image);
1101                }
1102                mutex_unlock(&kexec_mutex);
1103        }
1104}
1105
1106size_t crash_get_memory_size(void)
1107{
1108        size_t size = 0;
1109        mutex_lock(&kexec_mutex);
1110        if (crashk_res.end != crashk_res.start)
1111                size = resource_size(&crashk_res);
1112        mutex_unlock(&kexec_mutex);
1113        return size;
1114}
1115
1116void __weak crash_free_reserved_phys_range(unsigned long begin,
1117                                           unsigned long end)
1118{
1119        unsigned long addr;
1120
1121        for (addr = begin; addr < end; addr += PAGE_SIZE) {
1122                ClearPageReserved(pfn_to_page(addr >> PAGE_SHIFT));
1123                init_page_count(pfn_to_page(addr >> PAGE_SHIFT));
1124                free_page((unsigned long)__va(addr));
1125                totalram_pages++;
1126        }
1127}
1128
1129int crash_shrink_memory(unsigned long new_size)
1130{
1131        int ret = 0;
1132        unsigned long start, end;
1133        unsigned long old_size;
1134        struct resource *ram_res;
1135
1136        mutex_lock(&kexec_mutex);
1137
1138        if (kexec_crash_image) {
1139                ret = -ENOENT;
1140                goto unlock;
1141        }
1142        start = crashk_res.start;
1143        end = crashk_res.end;
1144        old_size = (end == 0) ? 0 : end - start + 1;
1145        if (new_size >= old_size) {
1146                ret = (new_size == old_size) ? 0 : -EINVAL;
1147                goto unlock;
1148        }
1149
1150        ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
1151        if (!ram_res) {
1152                ret = -ENOMEM;
1153                goto unlock;
1154        }
1155
1156        start = roundup(start, KEXEC_CRASH_MEM_ALIGN);
1157        end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN);
1158
1159        crash_map_reserved_pages();
1160        crash_free_reserved_phys_range(end, crashk_res.end);
1161
1162        if ((start == end) && (crashk_res.parent != NULL))
1163                release_resource(&crashk_res);
1164
1165        ram_res->start = end;
1166        ram_res->end = crashk_res.end;
1167        ram_res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
1168        ram_res->name = "System RAM";
1169
1170        crashk_res.end = end - 1;
1171
1172        insert_resource(&iomem_resource, ram_res);
1173        crash_unmap_reserved_pages();
1174
1175unlock:
1176        mutex_unlock(&kexec_mutex);
1177        return ret;
1178}
1179
1180static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
1181                            size_t data_len)
1182{
1183        struct elf_note note;
1184
1185        note.n_namesz = strlen(name) + 1;
1186        note.n_descsz = data_len;
1187        note.n_type   = type;
1188        memcpy(buf, &note, sizeof(note));
1189        buf += (sizeof(note) + 3)/4;
1190        memcpy(buf, name, note.n_namesz);
1191        buf += (note.n_namesz + 3)/4;
1192        memcpy(buf, data, note.n_descsz);
1193        buf += (note.n_descsz + 3)/4;
1194
1195        return buf;
1196}
1197
1198static void final_note(u32 *buf)
1199{
1200        struct elf_note note;
1201
1202        note.n_namesz = 0;
1203        note.n_descsz = 0;
1204        note.n_type   = 0;
1205        memcpy(buf, &note, sizeof(note));
1206}
1207
1208void crash_save_cpu(struct pt_regs *regs, int cpu)
1209{
1210        struct elf_prstatus prstatus;
1211        u32 *buf;
1212
1213        if ((cpu < 0) || (cpu >= nr_cpu_ids))
1214                return;
1215
1216        /* Using ELF notes here is opportunistic.
1217         * I need a well defined structure format
1218         * for the data I pass, and I need tags
1219         * on the data to indicate what information I have
1220         * squirrelled away.  ELF notes happen to provide
1221         * all of that, so there is no need to invent something new.
1222         */
1223        buf = (u32*)per_cpu_ptr(crash_notes, cpu);
1224        if (!buf)
1225                return;
1226        memset(&prstatus, 0, sizeof(prstatus));
1227        prstatus.pr_pid = current->pid;
1228        elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
1229        buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
1230                              &prstatus, sizeof(prstatus));
1231        final_note(buf);
1232}
1233
1234static int __init crash_notes_memory_init(void)
1235{
1236        /* Allocate memory for saving cpu registers. */
1237        crash_notes = alloc_percpu(note_buf_t);
1238        if (!crash_notes) {
1239                printk("Kexec: Memory allocation for saving cpu register"
1240                " states failed\n");
1241                return -ENOMEM;
1242        }
1243        return 0;
1244}
1245module_init(crash_notes_memory_init)
1246
1247
1248/*
1249 * parsing the "crashkernel" commandline
1250 *
1251 * this code is intended to be called from architecture specific code
1252 */
1253
1254
1255/*
1256 * This function parses command lines in the format
1257 *
1258 *   crashkernel=ramsize-range:size[,...][@offset]
1259 *
1260 * The function returns 0 on success and -EINVAL on failure.
1261 */
1262static int __init parse_crashkernel_mem(char                    *cmdline,
1263                                        unsigned long long      system_ram,
1264                                        unsigned long long      *crash_size,
1265                                        unsigned long long      *crash_base)
1266{
1267        char *cur = cmdline, *tmp;
1268
1269        /* for each entry of the comma-separated list */
1270        do {
1271                unsigned long long start, end = ULLONG_MAX, size;
1272
1273                /* get the start of the range */
1274                start = memparse(cur, &tmp);
1275                if (cur == tmp) {
1276                        pr_warning("crashkernel: Memory value expected\n");
1277                        return -EINVAL;
1278                }
1279                cur = tmp;
1280                if (*cur != '-') {
1281                        pr_warning("crashkernel: '-' expected\n");
1282                        return -EINVAL;
1283                }
1284                cur++;
1285
1286                /* if no ':' is here, than we read the end */
1287                if (*cur != ':') {
1288                        end = memparse(cur, &tmp);
1289                        if (cur == tmp) {
1290                                pr_warning("crashkernel: Memory "
1291                                                "value expected\n");
1292                                return -EINVAL;
1293                        }
1294                        cur = tmp;
1295                        if (end <= start) {
1296                                pr_warning("crashkernel: end <= start\n");
1297                                return -EINVAL;
1298                        }
1299                }
1300
1301                if (*cur != ':') {
1302                        pr_warning("crashkernel: ':' expected\n");
1303                        return -EINVAL;
1304                }
1305                cur++;
1306
1307                size = memparse(cur, &tmp);
1308                if (cur == tmp) {
1309                        pr_warning("Memory value expected\n");
1310                        return -EINVAL;
1311                }
1312                cur = tmp;
1313                if (size >= system_ram) {
1314                        pr_warning("crashkernel: invalid size\n");
1315                        return -EINVAL;
1316                }
1317
1318                /* match ? */
1319                if (system_ram >= start && system_ram < end) {
1320                        *crash_size = size;
1321                        break;
1322                }
1323        } while (*cur++ == ',');
1324
1325        if (*crash_size > 0) {
1326                while (*cur && *cur != ' ' && *cur != '@')
1327                        cur++;
1328                if (*cur == '@') {
1329                        cur++;
1330                        *crash_base = memparse(cur, &tmp);
1331                        if (cur == tmp) {
1332                                pr_warning("Memory value expected "
1333                                                "after '@'\n");
1334                                return -EINVAL;
1335                        }
1336                }
1337        }
1338
1339        return 0;
1340}
1341
1342/*
1343 * That function parses "simple" (old) crashkernel command lines like
1344 *
1345 *      crashkernel=size[@offset]
1346 *
1347 * It returns 0 on success and -EINVAL on failure.
1348 */
1349static int __init parse_crashkernel_simple(char                 *cmdline,
1350                                           unsigned long long   *crash_size,
1351                                           unsigned long long   *crash_base)
1352{
1353        char *cur = cmdline;
1354
1355        *crash_size = memparse(cmdline, &cur);
1356        if (cmdline == cur) {
1357                pr_warning("crashkernel: memory value expected\n");
1358                return -EINVAL;
1359        }
1360
1361        if (*cur == '@')
1362                *crash_base = memparse(cur+1, &cur);
1363        else if (*cur != ' ' && *cur != '\0') {
1364                pr_warning("crashkernel: unrecognized char\n");
1365                return -EINVAL;
1366        }
1367
1368        return 0;
1369}
1370
1371#define SUFFIX_HIGH 0
1372#define SUFFIX_LOW  1
1373#define SUFFIX_NULL 2
1374static __initdata char *suffix_tbl[] = {
1375        [SUFFIX_HIGH] = ",high",
1376        [SUFFIX_LOW]  = ",low",
1377        [SUFFIX_NULL] = NULL,
1378};
1379
1380/*
1381 * That function parses "suffix"  crashkernel command lines like
1382 *
1383 *      crashkernel=size,[high|low]
1384 *
1385 * It returns 0 on success and -EINVAL on failure.
1386 */
1387static int __init parse_crashkernel_suffix(char *cmdline,
1388                                           unsigned long long   *crash_size,
1389                                           unsigned long long   *crash_base,
1390                                           const char *suffix)
1391{
1392        char *cur = cmdline;
1393
1394        *crash_size = memparse(cmdline, &cur);
1395        if (cmdline == cur) {
1396                pr_warn("crashkernel: memory value expected\n");
1397                return -EINVAL;
1398        }
1399
1400        /* check with suffix */
1401        if (strncmp(cur, suffix, strlen(suffix))) {
1402                pr_warn("crashkernel: unrecognized char\n");
1403                return -EINVAL;
1404        }
1405        cur += strlen(suffix);
1406        if (*cur != ' ' && *cur != '\0') {
1407                pr_warn("crashkernel: unrecognized char\n");
1408                return -EINVAL;
1409        }
1410
1411        return 0;
1412}
1413
1414static __init char *get_last_crashkernel(char *cmdline,
1415                             const char *name,
1416                             const char *suffix)
1417{
1418        char *p = cmdline, *ck_cmdline = NULL;
1419
1420        /* find crashkernel and use the last one if there are more */
1421        p = strstr(p, name);
1422        while (p) {
1423                char *end_p = strchr(p, ' ');
1424                char *q;
1425
1426                if (!end_p)
1427                        end_p = p + strlen(p);
1428
1429                if (!suffix) {
1430                        int i;
1431
1432                        /* skip the one with any known suffix */
1433                        for (i = 0; suffix_tbl[i]; i++) {
1434                                q = end_p - strlen(suffix_tbl[i]);
1435                                if (!strncmp(q, suffix_tbl[i],
1436                                             strlen(suffix_tbl[i])))
1437                                        goto next;
1438                        }
1439                        ck_cmdline = p;
1440                } else {
1441                        q = end_p - strlen(suffix);
1442                        if (!strncmp(q, suffix, strlen(suffix)))
1443                                ck_cmdline = p;
1444                }
1445next:
1446                p = strstr(p+1, name);
1447        }
1448
1449        if (!ck_cmdline)
1450                return NULL;
1451
1452        return ck_cmdline;
1453}
1454
1455static int __init __parse_crashkernel(char *cmdline,
1456                             unsigned long long system_ram,
1457                             unsigned long long *crash_size,
1458                             unsigned long long *crash_base,
1459                             const char *name,
1460                             const char *suffix)
1461{
1462        char    *first_colon, *first_space;
1463        char    *ck_cmdline;
1464
1465        BUG_ON(!crash_size || !crash_base);
1466        *crash_size = 0;
1467        *crash_base = 0;
1468
1469        ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
1470
1471        if (!ck_cmdline)
1472                return -EINVAL;
1473
1474        ck_cmdline += strlen(name);
1475
1476        if (suffix)
1477                return parse_crashkernel_suffix(ck_cmdline, crash_size,
1478                                crash_base, suffix);
1479        /*
1480         * if the commandline contains a ':', then that's the extended
1481         * syntax -- if not, it must be the classic syntax
1482         */
1483        first_colon = strchr(ck_cmdline, ':');
1484        first_space = strchr(ck_cmdline, ' ');
1485        if (first_colon && (!first_space || first_colon < first_space))
1486                return parse_crashkernel_mem(ck_cmdline, system_ram,
1487                                crash_size, crash_base);
1488        else
1489                return parse_crashkernel_simple(ck_cmdline, crash_size,
1490                                crash_base);
1491
1492        return 0;
1493}
1494
1495/*
1496 * That function is the entry point for command line parsing and should be
1497 * called from the arch-specific code.
1498 */
1499int __init parse_crashkernel(char *cmdline,
1500                             unsigned long long system_ram,
1501                             unsigned long long *crash_size,
1502                             unsigned long long *crash_base)
1503{
1504        return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
1505                                        "crashkernel=", NULL);
1506}
1507
1508int __init parse_crashkernel_high(char *cmdline,
1509                             unsigned long long system_ram,
1510                             unsigned long long *crash_size,
1511                             unsigned long long *crash_base)
1512{
1513        return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
1514                                "crashkernel=", suffix_tbl[SUFFIX_HIGH]);
1515}
1516
1517int __init parse_crashkernel_low(char *cmdline,
1518                             unsigned long long system_ram,
1519                             unsigned long long *crash_size,
1520                             unsigned long long *crash_base)
1521{
1522        return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
1523                                "crashkernel=", suffix_tbl[SUFFIX_LOW]);
1524}
1525
1526static void update_vmcoreinfo_note(void)
1527{
1528        u32 *buf = vmcoreinfo_note;
1529
1530        if (!vmcoreinfo_size)
1531                return;
1532        buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
1533                              vmcoreinfo_size);
1534        final_note(buf);
1535}
1536
1537void crash_save_vmcoreinfo(void)
1538{
1539        vmcoreinfo_append_str("CRASHTIME=%ld\n", get_seconds());
1540        update_vmcoreinfo_note();
1541}
1542
1543void vmcoreinfo_append_str(const char *fmt, ...)
1544{
1545        va_list args;
1546        char buf[0x50];
1547        int r;
1548
1549        va_start(args, fmt);
1550        r = vsnprintf(buf, sizeof(buf), fmt, args);
1551        va_end(args);
1552
1553        if (r + vmcoreinfo_size > vmcoreinfo_max_size)
1554                r = vmcoreinfo_max_size - vmcoreinfo_size;
1555
1556        memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
1557
1558        vmcoreinfo_size += r;
1559}
1560
1561/*
1562 * provide an empty default implementation here -- architecture
1563 * code may override this
1564 */
1565void __attribute__ ((weak)) arch_crash_save_vmcoreinfo(void)
1566{}
1567
1568unsigned long __attribute__ ((weak)) paddr_vmcoreinfo_note(void)
1569{
1570        return __pa((unsigned long)(char *)&vmcoreinfo_note);
1571}
1572
1573static int __init crash_save_vmcoreinfo_init(void)
1574{
1575        VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
1576        VMCOREINFO_PAGESIZE(PAGE_SIZE);
1577
1578        VMCOREINFO_SYMBOL(init_uts_ns);
1579        VMCOREINFO_SYMBOL(node_online_map);
1580#ifdef CONFIG_MMU
1581        VMCOREINFO_SYMBOL(swapper_pg_dir);
1582#endif
1583        VMCOREINFO_SYMBOL(_stext);
1584        VMCOREINFO_SYMBOL(vmlist);
1585
1586#ifndef CONFIG_NEED_MULTIPLE_NODES
1587        VMCOREINFO_SYMBOL(mem_map);
1588        VMCOREINFO_SYMBOL(contig_page_data);
1589#endif
1590#ifdef CONFIG_SPARSEMEM
1591        VMCOREINFO_SYMBOL(mem_section);
1592        VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
1593        VMCOREINFO_STRUCT_SIZE(mem_section);
1594        VMCOREINFO_OFFSET(mem_section, section_mem_map);
1595#endif
1596        VMCOREINFO_STRUCT_SIZE(page);
1597        VMCOREINFO_STRUCT_SIZE(pglist_data);
1598        VMCOREINFO_STRUCT_SIZE(zone);
1599        VMCOREINFO_STRUCT_SIZE(free_area);
1600        VMCOREINFO_STRUCT_SIZE(list_head);
1601        VMCOREINFO_SIZE(nodemask_t);
1602        VMCOREINFO_OFFSET(page, flags);
1603        VMCOREINFO_OFFSET(page, _count);
1604        VMCOREINFO_OFFSET(page, mapping);
1605        VMCOREINFO_OFFSET(page, lru);
1606        VMCOREINFO_OFFSET(page, _mapcount);
1607        VMCOREINFO_OFFSET(page, private);
1608        VMCOREINFO_OFFSET(pglist_data, node_zones);
1609        VMCOREINFO_OFFSET(pglist_data, nr_zones);
1610#ifdef CONFIG_FLAT_NODE_MEM_MAP
1611        VMCOREINFO_OFFSET(pglist_data, node_mem_map);
1612#endif
1613        VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
1614        VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
1615        VMCOREINFO_OFFSET(pglist_data, node_id);
1616        VMCOREINFO_OFFSET(zone, free_area);
1617        VMCOREINFO_OFFSET(zone, vm_stat);
1618        VMCOREINFO_OFFSET(zone, spanned_pages);
1619        VMCOREINFO_OFFSET(free_area, free_list);
1620        VMCOREINFO_OFFSET(list_head, next);
1621        VMCOREINFO_OFFSET(list_head, prev);
1622        VMCOREINFO_OFFSET(vm_struct, addr);
1623        VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
1624        log_buf_kexec_setup();
1625        VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
1626        VMCOREINFO_NUMBER(NR_FREE_PAGES);
1627        VMCOREINFO_NUMBER(PG_lru);
1628        VMCOREINFO_NUMBER(PG_private);
1629        VMCOREINFO_NUMBER(PG_swapcache);
1630        VMCOREINFO_NUMBER(PG_slab);
1631#ifdef CONFIG_MEMORY_FAILURE
1632        VMCOREINFO_NUMBER(PG_hwpoison);
1633#endif
1634        VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
1635
1636        arch_crash_save_vmcoreinfo();
1637        update_vmcoreinfo_note();
1638
1639        return 0;
1640}
1641
1642module_init(crash_save_vmcoreinfo_init)
1643
1644/*
1645 * Move into place and start executing a preloaded standalone
1646 * executable.  If nothing was preloaded return an error.
1647 */
1648int kernel_kexec(void)
1649{
1650        int error = 0;
1651
1652        if (!mutex_trylock(&kexec_mutex))
1653                return -EBUSY;
1654        if (!kexec_image) {
1655                error = -EINVAL;
1656                goto Unlock;
1657        }
1658
1659#ifdef CONFIG_KEXEC_JUMP
1660        if (kexec_image->preserve_context) {
1661                lock_system_sleep();
1662                pm_prepare_console();
1663                error = freeze_processes();
1664                if (error) {
1665                        error = -EBUSY;
1666                        goto Restore_console;
1667                }
1668                suspend_console();
1669                error = dpm_suspend_start(PMSG_FREEZE);
1670                if (error)
1671                        goto Resume_console;
1672                /* At this point, dpm_suspend_start() has been called,
1673                 * but *not* dpm_suspend_end(). We *must* call
1674                 * dpm_suspend_end() now.  Otherwise, drivers for
1675                 * some devices (e.g. interrupt controllers) become
1676                 * desynchronized with the actual state of the
1677                 * hardware at resume time, and evil weirdness ensues.
1678                 */
1679                error = dpm_suspend_end(PMSG_FREEZE);
1680                if (error)
1681                        goto Resume_devices;
1682                error = disable_nonboot_cpus();
1683                if (error)
1684                        goto Enable_cpus;
1685                local_irq_disable();
1686                error = syscore_suspend();
1687                if (error)
1688                        goto Enable_irqs;
1689        } else
1690#endif
1691        {
1692                kernel_restart_prepare(NULL);
1693                printk(KERN_EMERG "Starting new kernel\n");
1694                machine_shutdown();
1695        }
1696
1697        machine_kexec(kexec_image);
1698
1699#ifdef CONFIG_KEXEC_JUMP
1700        if (kexec_image->preserve_context) {
1701                syscore_resume();
1702 Enable_irqs:
1703                local_irq_enable();
1704 Enable_cpus:
1705                enable_nonboot_cpus();
1706                dpm_resume_start(PMSG_RESTORE);
1707 Resume_devices:
1708                dpm_resume_end(PMSG_RESTORE);
1709 Resume_console:
1710                resume_console();
1711                thaw_processes();
1712 Restore_console:
1713                pm_restore_console();
1714                unlock_system_sleep();
1715        }
1716#endif
1717
1718 Unlock:
1719        mutex_unlock(&kexec_mutex);
1720        return error;
1721}
1722
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