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