linux/kernel/kexec.c
<<
>>
Prefs
   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        size_t 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 = min_t(size_t, mbytes,
 823                                PAGE_SIZE - (maddr & ~PAGE_MASK));
 824                uchunk = min(ubytes, mchunk);
 825
 826                result = copy_from_user(ptr, buf, uchunk);
 827                kunmap(page);
 828                if (result) {
 829                        result = -EFAULT;
 830                        goto out;
 831                }
 832                ubytes -= uchunk;
 833                maddr  += mchunk;
 834                buf    += mchunk;
 835                mbytes -= mchunk;
 836        }
 837out:
 838        return result;
 839}
 840
 841static int kimage_load_crash_segment(struct kimage *image,
 842                                        struct kexec_segment *segment)
 843{
 844        /* For crash dumps kernels we simply copy the data from
 845         * user space to it's destination.
 846         * We do things a page at a time for the sake of kmap.
 847         */
 848        unsigned long maddr;
 849        size_t ubytes, mbytes;
 850        int result;
 851        unsigned char __user *buf;
 852
 853        result = 0;
 854        buf = segment->buf;
 855        ubytes = segment->bufsz;
 856        mbytes = segment->memsz;
 857        maddr = segment->mem;
 858        while (mbytes) {
 859                struct page *page;
 860                char *ptr;
 861                size_t uchunk, mchunk;
 862
 863                page = pfn_to_page(maddr >> PAGE_SHIFT);
 864                if (!page) {
 865                        result  = -ENOMEM;
 866                        goto out;
 867                }
 868                ptr = kmap(page);
 869                ptr += maddr & ~PAGE_MASK;
 870                mchunk = min_t(size_t, mbytes,
 871                                PAGE_SIZE - (maddr & ~PAGE_MASK));
 872                uchunk = min(ubytes, mchunk);
 873                if (mchunk > uchunk) {
 874                        /* Zero the trailing part of the page */
 875                        memset(ptr + uchunk, 0, mchunk - uchunk);
 876                }
 877                result = copy_from_user(ptr, buf, uchunk);
 878                kexec_flush_icache_page(page);
 879                kunmap(page);
 880                if (result) {
 881                        result = -EFAULT;
 882                        goto out;
 883                }
 884                ubytes -= uchunk;
 885                maddr  += mchunk;
 886                buf    += mchunk;
 887                mbytes -= mchunk;
 888        }
 889out:
 890        return result;
 891}
 892
 893static int kimage_load_segment(struct kimage *image,
 894                                struct kexec_segment *segment)
 895{
 896        int result = -ENOMEM;
 897
 898        switch (image->type) {
 899        case KEXEC_TYPE_DEFAULT:
 900                result = kimage_load_normal_segment(image, segment);
 901                break;
 902        case KEXEC_TYPE_CRASH:
 903                result = kimage_load_crash_segment(image, segment);
 904                break;
 905        }
 906
 907        return result;
 908}
 909
 910/*
 911 * Exec Kernel system call: for obvious reasons only root may call it.
 912 *
 913 * This call breaks up into three pieces.
 914 * - A generic part which loads the new kernel from the current
 915 *   address space, and very carefully places the data in the
 916 *   allocated pages.
 917 *
 918 * - A generic part that interacts with the kernel and tells all of
 919 *   the devices to shut down.  Preventing on-going dmas, and placing
 920 *   the devices in a consistent state so a later kernel can
 921 *   reinitialize them.
 922 *
 923 * - A machine specific part that includes the syscall number
 924 *   and the copies the image to it's final destination.  And
 925 *   jumps into the image at entry.
 926 *
 927 * kexec does not sync, or unmount filesystems so if you need
 928 * that to happen you need to do that yourself.
 929 */
 930struct kimage *kexec_image;
 931struct kimage *kexec_crash_image;
 932
 933static DEFINE_MUTEX(kexec_mutex);
 934
 935SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
 936                struct kexec_segment __user *, segments, unsigned long, flags)
 937{
 938        struct kimage **dest_image, *image;
 939        int result;
 940
 941        /* We only trust the superuser with rebooting the system. */
 942        if (!capable(CAP_SYS_BOOT))
 943                return -EPERM;
 944
 945        /*
 946         * Verify we have a legal set of flags
 947         * This leaves us room for future extensions.
 948         */
 949        if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
 950                return -EINVAL;
 951
 952        /* Verify we are on the appropriate architecture */
 953        if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
 954                ((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
 955                return -EINVAL;
 956
 957        /* Put an artificial cap on the number
 958         * of segments passed to kexec_load.
 959         */
 960        if (nr_segments > KEXEC_SEGMENT_MAX)
 961                return -EINVAL;
 962
 963        image = NULL;
 964        result = 0;
 965
 966        /* Because we write directly to the reserved memory
 967         * region when loading crash kernels we need a mutex here to
 968         * prevent multiple crash  kernels from attempting to load
 969         * simultaneously, and to prevent a crash kernel from loading
 970         * over the top of a in use crash kernel.
 971         *
 972         * KISS: always take the mutex.
 973         */
 974        if (!mutex_trylock(&kexec_mutex))
 975                return -EBUSY;
 976
 977        dest_image = &kexec_image;
 978        if (flags & KEXEC_ON_CRASH)
 979                dest_image = &kexec_crash_image;
 980        if (nr_segments > 0) {
 981                unsigned long i;
 982
 983                /* Loading another kernel to reboot into */
 984                if ((flags & KEXEC_ON_CRASH) == 0)
 985                        result = kimage_normal_alloc(&image, entry,
 986                                                        nr_segments, segments);
 987                /* Loading another kernel to switch to if this one crashes */
 988                else if (flags & KEXEC_ON_CRASH) {
 989                        /* Free any current crash dump kernel before
 990                         * we corrupt it.
 991                         */
 992                        kimage_free(xchg(&kexec_crash_image, NULL));
 993                        result = kimage_crash_alloc(&image, entry,
 994                                                     nr_segments, segments);
 995                        crash_map_reserved_pages();
 996                }
 997                if (result)
 998                        goto out;
 999
1000                if (flags & KEXEC_PRESERVE_CONTEXT)
1001                        image->preserve_context = 1;
1002                result = machine_kexec_prepare(image);
1003                if (result)
1004                        goto out;
1005
1006                for (i = 0; i < nr_segments; i++) {
1007                        result = kimage_load_segment(image, &image->segment[i]);
1008                        if (result)
1009                                goto out;
1010                }
1011                kimage_terminate(image);
1012                if (flags & KEXEC_ON_CRASH)
1013                        crash_unmap_reserved_pages();
1014        }
1015        /* Install the new kernel, and  Uninstall the old */
1016        image = xchg(dest_image, image);
1017
1018out:
1019        mutex_unlock(&kexec_mutex);
1020        kimage_free(image);
1021
1022        return result;
1023}
1024
1025/*
1026 * Add and remove page tables for crashkernel memory
1027 *
1028 * Provide an empty default implementation here -- architecture
1029 * code may override this
1030 */
1031void __weak crash_map_reserved_pages(void)
1032{}
1033
1034void __weak crash_unmap_reserved_pages(void)
1035{}
1036
1037#ifdef CONFIG_COMPAT
1038asmlinkage long compat_sys_kexec_load(unsigned long entry,
1039                                unsigned long nr_segments,
1040                                struct compat_kexec_segment __user *segments,
1041                                unsigned long flags)
1042{
1043        struct compat_kexec_segment in;
1044        struct kexec_segment out, __user *ksegments;
1045        unsigned long i, result;
1046
1047        /* Don't allow clients that don't understand the native
1048         * architecture to do anything.
1049         */
1050        if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
1051                return -EINVAL;
1052
1053        if (nr_segments > KEXEC_SEGMENT_MAX)
1054                return -EINVAL;
1055
1056        ksegments = compat_alloc_user_space(nr_segments * sizeof(out));
1057        for (i=0; i < nr_segments; i++) {
1058                result = copy_from_user(&in, &segments[i], sizeof(in));
1059                if (result)
1060                        return -EFAULT;
1061
1062                out.buf   = compat_ptr(in.buf);
1063                out.bufsz = in.bufsz;
1064                out.mem   = in.mem;
1065                out.memsz = in.memsz;
1066
1067                result = copy_to_user(&ksegments[i], &out, sizeof(out));
1068                if (result)
1069                        return -EFAULT;
1070        }
1071
1072        return sys_kexec_load(entry, nr_segments, ksegments, flags);
1073}
1074#endif
1075
1076void crash_kexec(struct pt_regs *regs)
1077{
1078        /* Take the kexec_mutex here to prevent sys_kexec_load
1079         * running on one cpu from replacing the crash kernel
1080         * we are using after a panic on a different cpu.
1081         *
1082         * If the crash kernel was not located in a fixed area
1083         * of memory the xchg(&kexec_crash_image) would be
1084         * sufficient.  But since I reuse the memory...
1085         */
1086        if (mutex_trylock(&kexec_mutex)) {
1087                if (kexec_crash_image) {
1088                        struct pt_regs fixed_regs;
1089
1090                        crash_setup_regs(&fixed_regs, regs);
1091                        crash_save_vmcoreinfo();
1092                        machine_crash_shutdown(&fixed_regs);
1093                        machine_kexec(kexec_crash_image);
1094                }
1095                mutex_unlock(&kexec_mutex);
1096        }
1097}
1098
1099size_t crash_get_memory_size(void)
1100{
1101        size_t size = 0;
1102        mutex_lock(&kexec_mutex);
1103        if (crashk_res.end != crashk_res.start)
1104                size = resource_size(&crashk_res);
1105        mutex_unlock(&kexec_mutex);
1106        return size;
1107}
1108
1109void __weak crash_free_reserved_phys_range(unsigned long begin,
1110                                           unsigned long end)
1111{
1112        unsigned long addr;
1113
1114        for (addr = begin; addr < end; addr += PAGE_SIZE)
1115                free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
1116}
1117
1118int crash_shrink_memory(unsigned long new_size)
1119{
1120        int ret = 0;
1121        unsigned long start, end;
1122        unsigned long old_size;
1123        struct resource *ram_res;
1124
1125        mutex_lock(&kexec_mutex);
1126
1127        if (kexec_crash_image) {
1128                ret = -ENOENT;
1129                goto unlock;
1130        }
1131        start = crashk_res.start;
1132        end = crashk_res.end;
1133        old_size = (end == 0) ? 0 : end - start + 1;
1134        if (new_size >= old_size) {
1135                ret = (new_size == old_size) ? 0 : -EINVAL;
1136                goto unlock;
1137        }
1138
1139        ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
1140        if (!ram_res) {
1141                ret = -ENOMEM;
1142                goto unlock;
1143        }
1144
1145        start = roundup(start, KEXEC_CRASH_MEM_ALIGN);
1146        end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN);
1147
1148        crash_map_reserved_pages();
1149        crash_free_reserved_phys_range(end, crashk_res.end);
1150
1151        if ((start == end) && (crashk_res.parent != NULL))
1152                release_resource(&crashk_res);
1153
1154        ram_res->start = end;
1155        ram_res->end = crashk_res.end;
1156        ram_res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
1157        ram_res->name = "System RAM";
1158
1159        crashk_res.end = end - 1;
1160
1161        insert_resource(&iomem_resource, ram_res);
1162        crash_unmap_reserved_pages();
1163
1164unlock:
1165        mutex_unlock(&kexec_mutex);
1166        return ret;
1167}
1168
1169static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
1170                            size_t data_len)
1171{
1172        struct elf_note note;
1173
1174        note.n_namesz = strlen(name) + 1;
1175        note.n_descsz = data_len;
1176        note.n_type   = type;
1177        memcpy(buf, &note, sizeof(note));
1178        buf += (sizeof(note) + 3)/4;
1179        memcpy(buf, name, note.n_namesz);
1180        buf += (note.n_namesz + 3)/4;
1181        memcpy(buf, data, note.n_descsz);
1182        buf += (note.n_descsz + 3)/4;
1183
1184        return buf;
1185}
1186
1187static void final_note(u32 *buf)
1188{
1189        struct elf_note note;
1190
1191        note.n_namesz = 0;
1192        note.n_descsz = 0;
1193        note.n_type   = 0;
1194        memcpy(buf, &note, sizeof(note));
1195}
1196
1197void crash_save_cpu(struct pt_regs *regs, int cpu)
1198{
1199        struct elf_prstatus prstatus;
1200        u32 *buf;
1201
1202        if ((cpu < 0) || (cpu >= nr_cpu_ids))
1203                return;
1204
1205        /* Using ELF notes here is opportunistic.
1206         * I need a well defined structure format
1207         * for the data I pass, and I need tags
1208         * on the data to indicate what information I have
1209         * squirrelled away.  ELF notes happen to provide
1210         * all of that, so there is no need to invent something new.
1211         */
1212        buf = (u32*)per_cpu_ptr(crash_notes, cpu);
1213        if (!buf)
1214                return;
1215        memset(&prstatus, 0, sizeof(prstatus));
1216        prstatus.pr_pid = current->pid;
1217        elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
1218        buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
1219                              &prstatus, sizeof(prstatus));
1220        final_note(buf);
1221}
1222
1223static int __init crash_notes_memory_init(void)
1224{
1225        /* Allocate memory for saving cpu registers. */
1226        crash_notes = alloc_percpu(note_buf_t);
1227        if (!crash_notes) {
1228                printk("Kexec: Memory allocation for saving cpu register"
1229                " states failed\n");
1230                return -ENOMEM;
1231        }
1232        return 0;
1233}
1234module_init(crash_notes_memory_init)
1235
1236
1237/*
1238 * parsing the "crashkernel" commandline
1239 *
1240 * this code is intended to be called from architecture specific code
1241 */
1242
1243
1244/*
1245 * This function parses command lines in the format
1246 *
1247 *   crashkernel=ramsize-range:size[,...][@offset]
1248 *
1249 * The function returns 0 on success and -EINVAL on failure.
1250 */
1251static int __init parse_crashkernel_mem(char                    *cmdline,
1252                                        unsigned long long      system_ram,
1253                                        unsigned long long      *crash_size,
1254                                        unsigned long long      *crash_base)
1255{
1256        char *cur = cmdline, *tmp;
1257
1258        /* for each entry of the comma-separated list */
1259        do {
1260                unsigned long long start, end = ULLONG_MAX, size;
1261
1262                /* get the start of the range */
1263                start = memparse(cur, &tmp);
1264                if (cur == tmp) {
1265                        pr_warning("crashkernel: Memory value expected\n");
1266                        return -EINVAL;
1267                }
1268                cur = tmp;
1269                if (*cur != '-') {
1270                        pr_warning("crashkernel: '-' expected\n");
1271                        return -EINVAL;
1272                }
1273                cur++;
1274
1275                /* if no ':' is here, than we read the end */
1276                if (*cur != ':') {
1277                        end = memparse(cur, &tmp);
1278                        if (cur == tmp) {
1279                                pr_warning("crashkernel: Memory "
1280                                                "value expected\n");
1281                                return -EINVAL;
1282                        }
1283                        cur = tmp;
1284                        if (end <= start) {
1285                                pr_warning("crashkernel: end <= start\n");
1286                                return -EINVAL;
1287                        }
1288                }
1289
1290                if (*cur != ':') {
1291                        pr_warning("crashkernel: ':' expected\n");
1292                        return -EINVAL;
1293                }
1294                cur++;
1295
1296                size = memparse(cur, &tmp);
1297                if (cur == tmp) {
1298                        pr_warning("Memory value expected\n");
1299                        return -EINVAL;
1300                }
1301                cur = tmp;
1302                if (size >= system_ram) {
1303                        pr_warning("crashkernel: invalid size\n");
1304                        return -EINVAL;
1305                }
1306
1307                /* match ? */
1308                if (system_ram >= start && system_ram < end) {
1309                        *crash_size = size;
1310                        break;
1311                }
1312        } while (*cur++ == ',');
1313
1314        if (*crash_size > 0) {
1315                while (*cur && *cur != ' ' && *cur != '@')
1316                        cur++;
1317                if (*cur == '@') {
1318                        cur++;
1319                        *crash_base = memparse(cur, &tmp);
1320                        if (cur == tmp) {
1321                                pr_warning("Memory value expected "
1322                                                "after '@'\n");
1323                                return -EINVAL;
1324                        }
1325                }
1326        }
1327
1328        return 0;
1329}
1330
1331/*
1332 * That function parses "simple" (old) crashkernel command lines like
1333 *
1334 *      crashkernel=size[@offset]
1335 *
1336 * It returns 0 on success and -EINVAL on failure.
1337 */
1338static int __init parse_crashkernel_simple(char                 *cmdline,
1339                                           unsigned long long   *crash_size,
1340                                           unsigned long long   *crash_base)
1341{
1342        char *cur = cmdline;
1343
1344        *crash_size = memparse(cmdline, &cur);
1345        if (cmdline == cur) {
1346                pr_warning("crashkernel: memory value expected\n");
1347                return -EINVAL;
1348        }
1349
1350        if (*cur == '@')
1351                *crash_base = memparse(cur+1, &cur);
1352        else if (*cur != ' ' && *cur != '\0') {
1353                pr_warning("crashkernel: unrecognized char\n");
1354                return -EINVAL;
1355        }
1356
1357        return 0;
1358}
1359
1360#define SUFFIX_HIGH 0
1361#define SUFFIX_LOW  1
1362#define SUFFIX_NULL 2
1363static __initdata char *suffix_tbl[] = {
1364        [SUFFIX_HIGH] = ",high",
1365        [SUFFIX_LOW]  = ",low",
1366        [SUFFIX_NULL] = NULL,
1367};
1368
1369/*
1370 * That function parses "suffix"  crashkernel command lines like
1371 *
1372 *      crashkernel=size,[high|low]
1373 *
1374 * It returns 0 on success and -EINVAL on failure.
1375 */
1376static int __init parse_crashkernel_suffix(char *cmdline,
1377                                           unsigned long long   *crash_size,
1378                                           unsigned long long   *crash_base,
1379                                           const char *suffix)
1380{
1381        char *cur = cmdline;
1382
1383        *crash_size = memparse(cmdline, &cur);
1384        if (cmdline == cur) {
1385                pr_warn("crashkernel: memory value expected\n");
1386                return -EINVAL;
1387        }
1388
1389        /* check with suffix */
1390        if (strncmp(cur, suffix, strlen(suffix))) {
1391                pr_warn("crashkernel: unrecognized char\n");
1392                return -EINVAL;
1393        }
1394        cur += strlen(suffix);
1395        if (*cur != ' ' && *cur != '\0') {
1396                pr_warn("crashkernel: unrecognized char\n");
1397                return -EINVAL;
1398        }
1399
1400        return 0;
1401}
1402
1403static __init char *get_last_crashkernel(char *cmdline,
1404                             const char *name,
1405                             const char *suffix)
1406{
1407        char *p = cmdline, *ck_cmdline = NULL;
1408
1409        /* find crashkernel and use the last one if there are more */
1410        p = strstr(p, name);
1411        while (p) {
1412                char *end_p = strchr(p, ' ');
1413                char *q;
1414
1415                if (!end_p)
1416                        end_p = p + strlen(p);
1417
1418                if (!suffix) {
1419                        int i;
1420
1421                        /* skip the one with any known suffix */
1422                        for (i = 0; suffix_tbl[i]; i++) {
1423                                q = end_p - strlen(suffix_tbl[i]);
1424                                if (!strncmp(q, suffix_tbl[i],
1425                                             strlen(suffix_tbl[i])))
1426                                        goto next;
1427                        }
1428                        ck_cmdline = p;
1429                } else {
1430                        q = end_p - strlen(suffix);
1431                        if (!strncmp(q, suffix, strlen(suffix)))
1432                                ck_cmdline = p;
1433                }
1434next:
1435                p = strstr(p+1, name);
1436        }
1437
1438        if (!ck_cmdline)
1439                return NULL;
1440
1441        return ck_cmdline;
1442}
1443
1444static int __init __parse_crashkernel(char *cmdline,
1445                             unsigned long long system_ram,
1446                             unsigned long long *crash_size,
1447                             unsigned long long *crash_base,
1448                             const char *name,
1449                             const char *suffix)
1450{
1451        char    *first_colon, *first_space;
1452        char    *ck_cmdline;
1453
1454        BUG_ON(!crash_size || !crash_base);
1455        *crash_size = 0;
1456        *crash_base = 0;
1457
1458        ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
1459
1460        if (!ck_cmdline)
1461                return -EINVAL;
1462
1463        ck_cmdline += strlen(name);
1464
1465        if (suffix)
1466                return parse_crashkernel_suffix(ck_cmdline, crash_size,
1467                                crash_base, suffix);
1468        /*
1469         * if the commandline contains a ':', then that's the extended
1470         * syntax -- if not, it must be the classic syntax
1471         */
1472        first_colon = strchr(ck_cmdline, ':');
1473        first_space = strchr(ck_cmdline, ' ');
1474        if (first_colon && (!first_space || first_colon < first_space))
1475                return parse_crashkernel_mem(ck_cmdline, system_ram,
1476                                crash_size, crash_base);
1477        else
1478                return parse_crashkernel_simple(ck_cmdline, crash_size,
1479                                crash_base);
1480
1481        return 0;
1482}
1483
1484/*
1485 * That function is the entry point for command line parsing and should be
1486 * called from the arch-specific code.
1487 */
1488int __init parse_crashkernel(char *cmdline,
1489                             unsigned long long system_ram,
1490                             unsigned long long *crash_size,
1491                             unsigned long long *crash_base)
1492{
1493        return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
1494                                        "crashkernel=", NULL);
1495}
1496
1497int __init parse_crashkernel_high(char *cmdline,
1498                             unsigned long long system_ram,
1499                             unsigned long long *crash_size,
1500                             unsigned long long *crash_base)
1501{
1502        return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
1503                                "crashkernel=", suffix_tbl[SUFFIX_HIGH]);
1504}
1505
1506int __init parse_crashkernel_low(char *cmdline,
1507                             unsigned long long system_ram,
1508                             unsigned long long *crash_size,
1509                             unsigned long long *crash_base)
1510{
1511        return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
1512                                "crashkernel=", suffix_tbl[SUFFIX_LOW]);
1513}
1514
1515static void update_vmcoreinfo_note(void)
1516{
1517        u32 *buf = vmcoreinfo_note;
1518
1519        if (!vmcoreinfo_size)
1520                return;
1521        buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
1522                              vmcoreinfo_size);
1523        final_note(buf);
1524}
1525
1526void crash_save_vmcoreinfo(void)
1527{
1528        vmcoreinfo_append_str("CRASHTIME=%ld\n", get_seconds());
1529        update_vmcoreinfo_note();
1530}
1531
1532void vmcoreinfo_append_str(const char *fmt, ...)
1533{
1534        va_list args;
1535        char buf[0x50];
1536        size_t r;
1537
1538        va_start(args, fmt);
1539        r = vsnprintf(buf, sizeof(buf), fmt, args);
1540        va_end(args);
1541
1542        r = min(r, vmcoreinfo_max_size - vmcoreinfo_size);
1543
1544        memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
1545
1546        vmcoreinfo_size += r;
1547}
1548
1549/*
1550 * provide an empty default implementation here -- architecture
1551 * code may override this
1552 */
1553void __attribute__ ((weak)) arch_crash_save_vmcoreinfo(void)
1554{}
1555
1556unsigned long __attribute__ ((weak)) paddr_vmcoreinfo_note(void)
1557{
1558        return __pa((unsigned long)(char *)&vmcoreinfo_note);
1559}
1560
1561static int __init crash_save_vmcoreinfo_init(void)
1562{
1563        VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
1564        VMCOREINFO_PAGESIZE(PAGE_SIZE);
1565
1566        VMCOREINFO_SYMBOL(init_uts_ns);
1567        VMCOREINFO_SYMBOL(node_online_map);
1568#ifdef CONFIG_MMU
1569        VMCOREINFO_SYMBOL(swapper_pg_dir);
1570#endif
1571        VMCOREINFO_SYMBOL(_stext);
1572        VMCOREINFO_SYMBOL(vmap_area_list);
1573
1574#ifndef CONFIG_NEED_MULTIPLE_NODES
1575        VMCOREINFO_SYMBOL(mem_map);
1576        VMCOREINFO_SYMBOL(contig_page_data);
1577#endif
1578#ifdef CONFIG_SPARSEMEM
1579        VMCOREINFO_SYMBOL(mem_section);
1580        VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
1581        VMCOREINFO_STRUCT_SIZE(mem_section);
1582        VMCOREINFO_OFFSET(mem_section, section_mem_map);
1583#endif
1584        VMCOREINFO_STRUCT_SIZE(page);
1585        VMCOREINFO_STRUCT_SIZE(pglist_data);
1586        VMCOREINFO_STRUCT_SIZE(zone);
1587        VMCOREINFO_STRUCT_SIZE(free_area);
1588        VMCOREINFO_STRUCT_SIZE(list_head);
1589        VMCOREINFO_SIZE(nodemask_t);
1590        VMCOREINFO_OFFSET(page, flags);
1591        VMCOREINFO_OFFSET(page, _count);
1592        VMCOREINFO_OFFSET(page, mapping);
1593        VMCOREINFO_OFFSET(page, lru);
1594        VMCOREINFO_OFFSET(page, _mapcount);
1595        VMCOREINFO_OFFSET(page, private);
1596        VMCOREINFO_OFFSET(pglist_data, node_zones);
1597        VMCOREINFO_OFFSET(pglist_data, nr_zones);
1598#ifdef CONFIG_FLAT_NODE_MEM_MAP
1599        VMCOREINFO_OFFSET(pglist_data, node_mem_map);
1600#endif
1601        VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
1602        VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
1603        VMCOREINFO_OFFSET(pglist_data, node_id);
1604        VMCOREINFO_OFFSET(zone, free_area);
1605        VMCOREINFO_OFFSET(zone, vm_stat);
1606        VMCOREINFO_OFFSET(zone, spanned_pages);
1607        VMCOREINFO_OFFSET(free_area, free_list);
1608        VMCOREINFO_OFFSET(list_head, next);
1609        VMCOREINFO_OFFSET(list_head, prev);
1610        VMCOREINFO_OFFSET(vmap_area, va_start);
1611        VMCOREINFO_OFFSET(vmap_area, list);
1612        VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
1613        log_buf_kexec_setup();
1614        VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
1615        VMCOREINFO_NUMBER(NR_FREE_PAGES);
1616        VMCOREINFO_NUMBER(PG_lru);
1617        VMCOREINFO_NUMBER(PG_private);
1618        VMCOREINFO_NUMBER(PG_swapcache);
1619        VMCOREINFO_NUMBER(PG_slab);
1620#ifdef CONFIG_MEMORY_FAILURE
1621        VMCOREINFO_NUMBER(PG_hwpoison);
1622#endif
1623        VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
1624
1625        arch_crash_save_vmcoreinfo();
1626        update_vmcoreinfo_note();
1627
1628        return 0;
1629}
1630
1631module_init(crash_save_vmcoreinfo_init)
1632
1633/*
1634 * Move into place and start executing a preloaded standalone
1635 * executable.  If nothing was preloaded return an error.
1636 */
1637int kernel_kexec(void)
1638{
1639        int error = 0;
1640
1641        if (!mutex_trylock(&kexec_mutex))
1642                return -EBUSY;
1643        if (!kexec_image) {
1644                error = -EINVAL;
1645                goto Unlock;
1646        }
1647
1648#ifdef CONFIG_KEXEC_JUMP
1649        if (kexec_image->preserve_context) {
1650                lock_system_sleep();
1651                pm_prepare_console();
1652                error = freeze_processes();
1653                if (error) {
1654                        error = -EBUSY;
1655                        goto Restore_console;
1656                }
1657                suspend_console();
1658                error = dpm_suspend_start(PMSG_FREEZE);
1659                if (error)
1660                        goto Resume_console;
1661                /* At this point, dpm_suspend_start() has been called,
1662                 * but *not* dpm_suspend_end(). We *must* call
1663                 * dpm_suspend_end() now.  Otherwise, drivers for
1664                 * some devices (e.g. interrupt controllers) become
1665                 * desynchronized with the actual state of the
1666                 * hardware at resume time, and evil weirdness ensues.
1667                 */
1668                error = dpm_suspend_end(PMSG_FREEZE);
1669                if (error)
1670                        goto Resume_devices;
1671                error = disable_nonboot_cpus();
1672                if (error)
1673                        goto Enable_cpus;
1674                local_irq_disable();
1675                error = syscore_suspend();
1676                if (error)
1677                        goto Enable_irqs;
1678        } else
1679#endif
1680        {
1681                kernel_restart_prepare(NULL);
1682                printk(KERN_EMERG "Starting new kernel\n");
1683                machine_shutdown();
1684        }
1685
1686        machine_kexec(kexec_image);
1687
1688#ifdef CONFIG_KEXEC_JUMP
1689        if (kexec_image->preserve_context) {
1690                syscore_resume();
1691 Enable_irqs:
1692                local_irq_enable();
1693 Enable_cpus:
1694                enable_nonboot_cpus();
1695                dpm_resume_start(PMSG_RESTORE);
1696 Resume_devices:
1697                dpm_resume_end(PMSG_RESTORE);
1698 Resume_console:
1699                resume_console();
1700                thaw_processes();
1701 Restore_console:
1702                pm_restore_console();
1703                unlock_system_sleep();
1704        }
1705#endif
1706
1707 Unlock:
1708        mutex_unlock(&kexec_mutex);
1709        return error;
1710}
1711
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.