The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/minidump_machdep.c

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    1 /*-
    2  * Copyright (c) 2006 Peter Wemm
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  *
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD: releng/9.0/sys/i386/i386/minidump_machdep.c 221173 2011-04-28 16:02:05Z attilio $");
   29 
   30 #include "opt_watchdog.h"
   31 
   32 #include <sys/param.h>
   33 #include <sys/systm.h>
   34 #include <sys/conf.h>
   35 #include <sys/cons.h>
   36 #include <sys/kernel.h>
   37 #include <sys/kerneldump.h>
   38 #include <sys/msgbuf.h>
   39 #ifdef SW_WATCHDOG
   40 #include <sys/watchdog.h>
   41 #endif
   42 #include <vm/vm.h>
   43 #include <vm/pmap.h>
   44 #include <machine/atomic.h>
   45 #include <machine/elf.h>
   46 #include <machine/md_var.h>
   47 #include <machine/vmparam.h>
   48 #include <machine/minidump.h>
   49 
   50 CTASSERT(sizeof(struct kerneldumpheader) == 512);
   51 
   52 /*
   53  * Don't touch the first SIZEOF_METADATA bytes on the dump device. This
   54  * is to protect us from metadata and to protect metadata from us.
   55  */
   56 #define SIZEOF_METADATA         (64*1024)
   57 
   58 #define MD_ALIGN(x)     (((off_t)(x) + PAGE_MASK) & ~PAGE_MASK)
   59 #define DEV_ALIGN(x)    (((off_t)(x) + (DEV_BSIZE-1)) & ~(DEV_BSIZE-1))
   60 
   61 uint32_t *vm_page_dump;
   62 int vm_page_dump_size;
   63 
   64 static struct kerneldumpheader kdh;
   65 static off_t dumplo;
   66 
   67 /* Handle chunked writes. */
   68 static size_t fragsz;
   69 static void *dump_va;
   70 static uint64_t counter, progress;
   71 
   72 CTASSERT(sizeof(*vm_page_dump) == 4);
   73 #ifndef XEN
   74 #define xpmap_mtop(x) (x)
   75 #define xpmap_ptom(x) (x)
   76 #endif
   77 
   78 
   79 static int
   80 is_dumpable(vm_paddr_t pa)
   81 {
   82         int i;
   83 
   84         for (i = 0; dump_avail[i] != 0 || dump_avail[i + 1] != 0; i += 2) {
   85                 if (pa >= dump_avail[i] && pa < dump_avail[i + 1])
   86                         return (1);
   87         }
   88         return (0);
   89 }
   90 
   91 #define PG2MB(pgs) (((pgs) + (1 << 8) - 1) >> 8)
   92 
   93 static int
   94 blk_flush(struct dumperinfo *di)
   95 {
   96         int error;
   97 
   98         if (fragsz == 0)
   99                 return (0);
  100 
  101         error = dump_write(di, dump_va, 0, dumplo, fragsz);
  102         dumplo += fragsz;
  103         fragsz = 0;
  104         return (error);
  105 }
  106 
  107 static int
  108 blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
  109 {
  110         size_t len;
  111         int error, i, c;
  112         u_int maxdumpsz;
  113 
  114         maxdumpsz = min(di->maxiosize, MAXDUMPPGS * PAGE_SIZE);
  115         if (maxdumpsz == 0)     /* seatbelt */
  116                 maxdumpsz = PAGE_SIZE;
  117         error = 0;
  118         if ((sz % PAGE_SIZE) != 0) {
  119                 printf("size not page aligned\n");
  120                 return (EINVAL);
  121         }
  122         if (ptr != NULL && pa != 0) {
  123                 printf("cant have both va and pa!\n");
  124                 return (EINVAL);
  125         }
  126         if (pa != 0 && (((uintptr_t)ptr) % PAGE_SIZE) != 0) {
  127                 printf("address not page aligned\n");
  128                 return (EINVAL);
  129         }
  130         if (ptr != NULL) {
  131                 /* If we're doing a virtual dump, flush any pre-existing pa pages */
  132                 error = blk_flush(di);
  133                 if (error)
  134                         return (error);
  135         }
  136         while (sz) {
  137                 len = maxdumpsz - fragsz;
  138                 if (len > sz)
  139                         len = sz;
  140                 counter += len;
  141                 progress -= len;
  142                 if (counter >> 24) {
  143                         printf(" %lld", PG2MB(progress >> PAGE_SHIFT));
  144                         counter &= (1<<24) - 1;
  145                 }
  146 #ifdef SW_WATCHDOG
  147                 wdog_kern_pat(WD_LASTVAL);
  148 #endif
  149                 if (ptr) {
  150                         error = dump_write(di, ptr, 0, dumplo, len);
  151                         if (error)
  152                                 return (error);
  153                         dumplo += len;
  154                         ptr += len;
  155                         sz -= len;
  156                 } else {
  157                         for (i = 0; i < len; i += PAGE_SIZE)
  158                                 dump_va = pmap_kenter_temporary(pa + i, (i + fragsz) >> PAGE_SHIFT);
  159                         fragsz += len;
  160                         pa += len;
  161                         sz -= len;
  162                         if (fragsz == maxdumpsz) {
  163                                 error = blk_flush(di);
  164                                 if (error)
  165                                         return (error);
  166                         }
  167                 }
  168 
  169                 /* Check for user abort. */
  170                 c = cncheckc();
  171                 if (c == 0x03)
  172                         return (ECANCELED);
  173                 if (c != -1)
  174                         printf(" (CTRL-C to abort) ");
  175         }
  176 
  177         return (0);
  178 }
  179 
  180 /* A fake page table page, to avoid having to handle both 4K and 2M pages */
  181 static pt_entry_t fakept[NPTEPG];
  182 
  183 void
  184 minidumpsys(struct dumperinfo *di)
  185 {
  186         uint64_t dumpsize;
  187         uint32_t ptesize;
  188         vm_offset_t va;
  189         int error;
  190         uint32_t bits;
  191         uint64_t pa;
  192         pd_entry_t *pd;
  193         pt_entry_t *pt;
  194         int i, j, k, bit;
  195         struct minidumphdr mdhdr;
  196 
  197         counter = 0;
  198         /* Walk page table pages, set bits in vm_page_dump */
  199         ptesize = 0;
  200         for (va = KERNBASE; va < kernel_vm_end; va += NBPDR) {
  201                 /*
  202                  * We always write a page, even if it is zero. Each
  203                  * page written corresponds to 2MB of space
  204                  */
  205                 ptesize += PAGE_SIZE;
  206                 pd = (pd_entry_t *)((uintptr_t)IdlePTD + KERNBASE);     /* always mapped! */
  207                 j = va >> PDRSHIFT;
  208                 if ((pd[j] & (PG_PS | PG_V)) == (PG_PS | PG_V))  {
  209                         /* This is an entire 2M page. */
  210                         pa = xpmap_mtop(pd[j] & PG_PS_FRAME);
  211                         for (k = 0; k < NPTEPG; k++) {
  212                                 if (is_dumpable(pa))
  213                                         dump_add_page(pa);
  214                                 pa += PAGE_SIZE;
  215                         }
  216                         continue;
  217                 }
  218                 if ((pd[j] & PG_V) == PG_V) {
  219                         /* set bit for each valid page in this 2MB block */
  220                         pt = pmap_kenter_temporary(xpmap_mtop(pd[j] & PG_FRAME), 0);
  221                         for (k = 0; k < NPTEPG; k++) {
  222                                 if ((pt[k] & PG_V) == PG_V) {
  223                                         pa = xpmap_mtop(pt[k] & PG_FRAME);
  224                                         if (is_dumpable(pa))
  225                                                 dump_add_page(pa);
  226                                 }
  227                         }
  228                 } else {
  229                         /* nothing, we're going to dump a null page */
  230                 }
  231         }
  232 
  233         /* Calculate dump size. */
  234         dumpsize = ptesize;
  235         dumpsize += round_page(msgbufp->msg_size);
  236         dumpsize += round_page(vm_page_dump_size);
  237         for (i = 0; i < vm_page_dump_size / sizeof(*vm_page_dump); i++) {
  238                 bits = vm_page_dump[i];
  239                 while (bits) {
  240                         bit = bsfl(bits);
  241                         pa = (((uint64_t)i * sizeof(*vm_page_dump) * NBBY) + bit) * PAGE_SIZE;
  242                         /* Clear out undumpable pages now if needed */
  243                         if (is_dumpable(pa)) {
  244                                 dumpsize += PAGE_SIZE;
  245                         } else {
  246                                 dump_drop_page(pa);
  247                         }
  248                         bits &= ~(1ul << bit);
  249                 }
  250         }
  251         dumpsize += PAGE_SIZE;
  252 
  253         /* Determine dump offset on device. */
  254         if (di->mediasize < SIZEOF_METADATA + dumpsize + sizeof(kdh) * 2) {
  255                 error = ENOSPC;
  256                 goto fail;
  257         }
  258         dumplo = di->mediaoffset + di->mediasize - dumpsize;
  259         dumplo -= sizeof(kdh) * 2;
  260         progress = dumpsize;
  261 
  262         /* Initialize mdhdr */
  263         bzero(&mdhdr, sizeof(mdhdr));
  264         strcpy(mdhdr.magic, MINIDUMP_MAGIC);
  265         mdhdr.version = MINIDUMP_VERSION;
  266         mdhdr.msgbufsize = msgbufp->msg_size;
  267         mdhdr.bitmapsize = vm_page_dump_size;
  268         mdhdr.ptesize = ptesize;
  269         mdhdr.kernbase = KERNBASE;
  270 #ifdef PAE
  271         mdhdr.paemode = 1;
  272 #endif
  273 
  274         mkdumpheader(&kdh, KERNELDUMPMAGIC, KERNELDUMP_I386_VERSION, dumpsize, di->blocksize);
  275 
  276         printf("Physical memory: %ju MB\n", ptoa((uintmax_t)physmem) / 1048576);
  277         printf("Dumping %llu MB:", (long long)dumpsize >> 20);
  278 
  279         /* Dump leader */
  280         error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
  281         if (error)
  282                 goto fail;
  283         dumplo += sizeof(kdh);
  284 
  285         /* Dump my header */
  286         bzero(&fakept, sizeof(fakept));
  287         bcopy(&mdhdr, &fakept, sizeof(mdhdr));
  288         error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
  289         if (error)
  290                 goto fail;
  291 
  292         /* Dump msgbuf up front */
  293         error = blk_write(di, (char *)msgbufp->msg_ptr, 0, round_page(msgbufp->msg_size));
  294         if (error)
  295                 goto fail;
  296 
  297         /* Dump bitmap */
  298         error = blk_write(di, (char *)vm_page_dump, 0, round_page(vm_page_dump_size));
  299         if (error)
  300                 goto fail;
  301 
  302         /* Dump kernel page table pages */
  303         for (va = KERNBASE; va < kernel_vm_end; va += NBPDR) {
  304                 /* We always write a page, even if it is zero */
  305                 pd = (pd_entry_t *)((uintptr_t)IdlePTD + KERNBASE);     /* always mapped! */
  306                 j = va >> PDRSHIFT;
  307                 if ((pd[j] & (PG_PS | PG_V)) == (PG_PS | PG_V))  {
  308                         /* This is a single 2M block. Generate a fake PTP */
  309                         pa = pd[j] & PG_PS_FRAME;
  310                         for (k = 0; k < NPTEPG; k++) {
  311                                 fakept[k] = (pa + (k * PAGE_SIZE)) | PG_V | PG_RW | PG_A | PG_M;
  312                         }
  313                         error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
  314                         if (error)
  315                                 goto fail;
  316                         /* flush, in case we reuse fakept in the same block */
  317                         error = blk_flush(di);
  318                         if (error)
  319                                 goto fail;
  320                         continue;
  321                 }
  322                 if ((pd[j] & PG_V) == PG_V) {
  323                         pa = xpmap_mtop(pd[j] & PG_FRAME);
  324 #ifndef XEN
  325                         error = blk_write(di, 0, pa, PAGE_SIZE);
  326 #else
  327                         pt = pmap_kenter_temporary(pa, 0);
  328                         memcpy(fakept, pt, PAGE_SIZE);
  329                         for (i = 0; i < NPTEPG; i++) 
  330                                 fakept[i] = xpmap_mtop(fakept[i]);
  331                         error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
  332                         if (error)
  333                                 goto fail;
  334                         /* flush, in case we reuse fakept in the same block */
  335                         error = blk_flush(di);
  336                         if (error)
  337                                 goto fail;
  338                         bzero(fakept, sizeof(fakept));
  339 #endif                  
  340                         
  341                         if (error)
  342                                 goto fail;
  343                 } else {
  344                         bzero(fakept, sizeof(fakept));
  345                         error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
  346                         if (error)
  347                                 goto fail;
  348                         /* flush, in case we reuse fakept in the same block */
  349                         error = blk_flush(di);
  350                         if (error)
  351                                 goto fail;
  352                 }
  353         }
  354 
  355         /* Dump memory chunks */
  356         /* XXX cluster it up and use blk_dump() */
  357         for (i = 0; i < vm_page_dump_size / sizeof(*vm_page_dump); i++) {
  358                 bits = vm_page_dump[i];
  359                 while (bits) {
  360                         bit = bsfl(bits);
  361                         pa = (((uint64_t)i * sizeof(*vm_page_dump) * NBBY) + bit) * PAGE_SIZE;
  362                         error = blk_write(di, 0, pa, PAGE_SIZE);
  363                         if (error)
  364                                 goto fail;
  365                         bits &= ~(1ul << bit);
  366                 }
  367         }
  368 
  369         error = blk_flush(di);
  370         if (error)
  371                 goto fail;
  372 
  373         /* Dump trailer */
  374         error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
  375         if (error)
  376                 goto fail;
  377         dumplo += sizeof(kdh);
  378 
  379         /* Signal completion, signoff and exit stage left. */
  380         dump_write(di, NULL, 0, 0, 0);
  381         printf("\nDump complete\n");
  382         return;
  383 
  384  fail:
  385         if (error < 0)
  386                 error = -error;
  387 
  388         if (error == ECANCELED)
  389                 printf("\nDump aborted\n");
  390         else if (error == ENOSPC)
  391                 printf("\nDump failed. Partition too small.\n");
  392         else
  393                 printf("\n** DUMP FAILED (ERROR %d) **\n", error);
  394 }
  395 
  396 void
  397 dump_add_page(vm_paddr_t pa)
  398 {
  399         int idx, bit;
  400 
  401         pa >>= PAGE_SHIFT;
  402         idx = pa >> 5;          /* 2^5 = 32 */
  403         bit = pa & 31;
  404         atomic_set_int(&vm_page_dump[idx], 1ul << bit);
  405 }
  406 
  407 void
  408 dump_drop_page(vm_paddr_t pa)
  409 {
  410         int idx, bit;
  411 
  412         pa >>= PAGE_SHIFT;
  413         idx = pa >> 5;          /* 2^5 = 32 */
  414         bit = pa & 31;
  415         atomic_clear_int(&vm_page_dump[idx], 1ul << bit);
  416 }
  417 

Cache object: 21142da60982063c3a186eab0a505ed2


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