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/10.1/sys/i386/i386/minidump_machdep.c 236503 2012-06-03 08:01:12Z avg $");
   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 #include <sys/watchdog.h>
   40 #include <vm/vm.h>
   41 #include <vm/pmap.h>
   42 #include <machine/atomic.h>
   43 #include <machine/elf.h>
   44 #include <machine/md_var.h>
   45 #include <machine/vmparam.h>
   46 #include <machine/minidump.h>
   47 
   48 CTASSERT(sizeof(struct kerneldumpheader) == 512);
   49 
   50 /*
   51  * Don't touch the first SIZEOF_METADATA bytes on the dump device. This
   52  * is to protect us from metadata and to protect metadata from us.
   53  */
   54 #define SIZEOF_METADATA         (64*1024)
   55 
   56 #define MD_ALIGN(x)     (((off_t)(x) + PAGE_MASK) & ~PAGE_MASK)
   57 #define DEV_ALIGN(x)    (((off_t)(x) + (DEV_BSIZE-1)) & ~(DEV_BSIZE-1))
   58 
   59 uint32_t *vm_page_dump;
   60 int vm_page_dump_size;
   61 
   62 static struct kerneldumpheader kdh;
   63 static off_t dumplo;
   64 
   65 /* Handle chunked writes. */
   66 static size_t fragsz;
   67 static void *dump_va;
   68 static uint64_t counter, progress;
   69 
   70 CTASSERT(sizeof(*vm_page_dump) == 4);
   71 #ifndef XEN
   72 #define xpmap_mtop(x) (x)
   73 #define xpmap_ptom(x) (x)
   74 #endif
   75 
   76 
   77 static int
   78 is_dumpable(vm_paddr_t pa)
   79 {
   80         int i;
   81 
   82         for (i = 0; dump_avail[i] != 0 || dump_avail[i + 1] != 0; i += 2) {
   83                 if (pa >= dump_avail[i] && pa < dump_avail[i + 1])
   84                         return (1);
   85         }
   86         return (0);
   87 }
   88 
   89 #define PG2MB(pgs) (((pgs) + (1 << 8) - 1) >> 8)
   90 
   91 static int
   92 blk_flush(struct dumperinfo *di)
   93 {
   94         int error;
   95 
   96         if (fragsz == 0)
   97                 return (0);
   98 
   99         error = dump_write(di, dump_va, 0, dumplo, fragsz);
  100         dumplo += fragsz;
  101         fragsz = 0;
  102         return (error);
  103 }
  104 
  105 static int
  106 blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
  107 {
  108         size_t len;
  109         int error, i, c;
  110         u_int maxdumpsz;
  111 
  112         maxdumpsz = min(di->maxiosize, MAXDUMPPGS * PAGE_SIZE);
  113         if (maxdumpsz == 0)     /* seatbelt */
  114                 maxdumpsz = PAGE_SIZE;
  115         error = 0;
  116         if ((sz % PAGE_SIZE) != 0) {
  117                 printf("size not page aligned\n");
  118                 return (EINVAL);
  119         }
  120         if (ptr != NULL && pa != 0) {
  121                 printf("cant have both va and pa!\n");
  122                 return (EINVAL);
  123         }
  124         if (pa != 0 && (((uintptr_t)ptr) % PAGE_SIZE) != 0) {
  125                 printf("address not page aligned\n");
  126                 return (EINVAL);
  127         }
  128         if (ptr != NULL) {
  129                 /* If we're doing a virtual dump, flush any pre-existing pa pages */
  130                 error = blk_flush(di);
  131                 if (error)
  132                         return (error);
  133         }
  134         while (sz) {
  135                 len = maxdumpsz - fragsz;
  136                 if (len > sz)
  137                         len = sz;
  138                 counter += len;
  139                 progress -= len;
  140                 if (counter >> 24) {
  141                         printf(" %lld", PG2MB(progress >> PAGE_SHIFT));
  142                         counter &= (1<<24) - 1;
  143                 }
  144 
  145                 wdog_kern_pat(WD_LASTVAL);
  146 
  147                 if (ptr) {
  148                         error = dump_write(di, ptr, 0, dumplo, len);
  149                         if (error)
  150                                 return (error);
  151                         dumplo += len;
  152                         ptr += len;
  153                         sz -= len;
  154                 } else {
  155                         for (i = 0; i < len; i += PAGE_SIZE)
  156                                 dump_va = pmap_kenter_temporary(pa + i, (i + fragsz) >> PAGE_SHIFT);
  157                         fragsz += len;
  158                         pa += len;
  159                         sz -= len;
  160                         if (fragsz == maxdumpsz) {
  161                                 error = blk_flush(di);
  162                                 if (error)
  163                                         return (error);
  164                         }
  165                 }
  166 
  167                 /* Check for user abort. */
  168                 c = cncheckc();
  169                 if (c == 0x03)
  170                         return (ECANCELED);
  171                 if (c != -1)
  172                         printf(" (CTRL-C to abort) ");
  173         }
  174 
  175         return (0);
  176 }
  177 
  178 /* A fake page table page, to avoid having to handle both 4K and 2M pages */
  179 static pt_entry_t fakept[NPTEPG];
  180 
  181 void
  182 minidumpsys(struct dumperinfo *di)
  183 {
  184         uint64_t dumpsize;
  185         uint32_t ptesize;
  186         vm_offset_t va;
  187         int error;
  188         uint32_t bits;
  189         uint64_t pa;
  190         pd_entry_t *pd;
  191         pt_entry_t *pt;
  192         int i, j, k, bit;
  193         struct minidumphdr mdhdr;
  194 
  195         counter = 0;
  196         /* Walk page table pages, set bits in vm_page_dump */
  197         ptesize = 0;
  198         for (va = KERNBASE; va < kernel_vm_end; va += NBPDR) {
  199                 /*
  200                  * We always write a page, even if it is zero. Each
  201                  * page written corresponds to 2MB of space
  202                  */
  203                 ptesize += PAGE_SIZE;
  204                 pd = (pd_entry_t *)((uintptr_t)IdlePTD + KERNBASE);     /* always mapped! */
  205                 j = va >> PDRSHIFT;
  206                 if ((pd[j] & (PG_PS | PG_V)) == (PG_PS | PG_V))  {
  207                         /* This is an entire 2M page. */
  208                         pa = xpmap_mtop(pd[j] & PG_PS_FRAME);
  209                         for (k = 0; k < NPTEPG; k++) {
  210                                 if (is_dumpable(pa))
  211                                         dump_add_page(pa);
  212                                 pa += PAGE_SIZE;
  213                         }
  214                         continue;
  215                 }
  216                 if ((pd[j] & PG_V) == PG_V) {
  217                         /* set bit for each valid page in this 2MB block */
  218                         pt = pmap_kenter_temporary(xpmap_mtop(pd[j] & PG_FRAME), 0);
  219                         for (k = 0; k < NPTEPG; k++) {
  220                                 if ((pt[k] & PG_V) == PG_V) {
  221                                         pa = xpmap_mtop(pt[k] & PG_FRAME);
  222                                         if (is_dumpable(pa))
  223                                                 dump_add_page(pa);
  224                                 }
  225                         }
  226                 } else {
  227                         /* nothing, we're going to dump a null page */
  228                 }
  229         }
  230 
  231         /* Calculate dump size. */
  232         dumpsize = ptesize;
  233         dumpsize += round_page(msgbufp->msg_size);
  234         dumpsize += round_page(vm_page_dump_size);
  235         for (i = 0; i < vm_page_dump_size / sizeof(*vm_page_dump); i++) {
  236                 bits = vm_page_dump[i];
  237                 while (bits) {
  238                         bit = bsfl(bits);
  239                         pa = (((uint64_t)i * sizeof(*vm_page_dump) * NBBY) + bit) * PAGE_SIZE;
  240                         /* Clear out undumpable pages now if needed */
  241                         if (is_dumpable(pa)) {
  242                                 dumpsize += PAGE_SIZE;
  243                         } else {
  244                                 dump_drop_page(pa);
  245                         }
  246                         bits &= ~(1ul << bit);
  247                 }
  248         }
  249         dumpsize += PAGE_SIZE;
  250 
  251         /* Determine dump offset on device. */
  252         if (di->mediasize < SIZEOF_METADATA + dumpsize + sizeof(kdh) * 2) {
  253                 error = ENOSPC;
  254                 goto fail;
  255         }
  256         dumplo = di->mediaoffset + di->mediasize - dumpsize;
  257         dumplo -= sizeof(kdh) * 2;
  258         progress = dumpsize;
  259 
  260         /* Initialize mdhdr */
  261         bzero(&mdhdr, sizeof(mdhdr));
  262         strcpy(mdhdr.magic, MINIDUMP_MAGIC);
  263         mdhdr.version = MINIDUMP_VERSION;
  264         mdhdr.msgbufsize = msgbufp->msg_size;
  265         mdhdr.bitmapsize = vm_page_dump_size;
  266         mdhdr.ptesize = ptesize;
  267         mdhdr.kernbase = KERNBASE;
  268 #ifdef PAE
  269         mdhdr.paemode = 1;
  270 #endif
  271 
  272         mkdumpheader(&kdh, KERNELDUMPMAGIC, KERNELDUMP_I386_VERSION, dumpsize, di->blocksize);
  273 
  274         printf("Physical memory: %ju MB\n", ptoa((uintmax_t)physmem) / 1048576);
  275         printf("Dumping %llu MB:", (long long)dumpsize >> 20);
  276 
  277         /* Dump leader */
  278         error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
  279         if (error)
  280                 goto fail;
  281         dumplo += sizeof(kdh);
  282 
  283         /* Dump my header */
  284         bzero(&fakept, sizeof(fakept));
  285         bcopy(&mdhdr, &fakept, sizeof(mdhdr));
  286         error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
  287         if (error)
  288                 goto fail;
  289 
  290         /* Dump msgbuf up front */
  291         error = blk_write(di, (char *)msgbufp->msg_ptr, 0, round_page(msgbufp->msg_size));
  292         if (error)
  293                 goto fail;
  294 
  295         /* Dump bitmap */
  296         error = blk_write(di, (char *)vm_page_dump, 0, round_page(vm_page_dump_size));
  297         if (error)
  298                 goto fail;
  299 
  300         /* Dump kernel page table pages */
  301         for (va = KERNBASE; va < kernel_vm_end; va += NBPDR) {
  302                 /* We always write a page, even if it is zero */
  303                 pd = (pd_entry_t *)((uintptr_t)IdlePTD + KERNBASE);     /* always mapped! */
  304                 j = va >> PDRSHIFT;
  305                 if ((pd[j] & (PG_PS | PG_V)) == (PG_PS | PG_V))  {
  306                         /* This is a single 2M block. Generate a fake PTP */
  307                         pa = pd[j] & PG_PS_FRAME;
  308                         for (k = 0; k < NPTEPG; k++) {
  309                                 fakept[k] = (pa + (k * PAGE_SIZE)) | PG_V | PG_RW | PG_A | PG_M;
  310                         }
  311                         error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
  312                         if (error)
  313                                 goto fail;
  314                         /* flush, in case we reuse fakept in the same block */
  315                         error = blk_flush(di);
  316                         if (error)
  317                                 goto fail;
  318                         continue;
  319                 }
  320                 if ((pd[j] & PG_V) == PG_V) {
  321                         pa = xpmap_mtop(pd[j] & PG_FRAME);
  322 #ifndef XEN
  323                         error = blk_write(di, 0, pa, PAGE_SIZE);
  324 #else
  325                         pt = pmap_kenter_temporary(pa, 0);
  326                         memcpy(fakept, pt, PAGE_SIZE);
  327                         for (i = 0; i < NPTEPG; i++) 
  328                                 fakept[i] = xpmap_mtop(fakept[i]);
  329                         error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
  330                         if (error)
  331                                 goto fail;
  332                         /* flush, in case we reuse fakept in the same block */
  333                         error = blk_flush(di);
  334                         if (error)
  335                                 goto fail;
  336                         bzero(fakept, sizeof(fakept));
  337 #endif                  
  338                         
  339                         if (error)
  340                                 goto fail;
  341                 } else {
  342                         bzero(fakept, sizeof(fakept));
  343                         error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
  344                         if (error)
  345                                 goto fail;
  346                         /* flush, in case we reuse fakept in the same block */
  347                         error = blk_flush(di);
  348                         if (error)
  349                                 goto fail;
  350                 }
  351         }
  352 
  353         /* Dump memory chunks */
  354         /* XXX cluster it up and use blk_dump() */
  355         for (i = 0; i < vm_page_dump_size / sizeof(*vm_page_dump); i++) {
  356                 bits = vm_page_dump[i];
  357                 while (bits) {
  358                         bit = bsfl(bits);
  359                         pa = (((uint64_t)i * sizeof(*vm_page_dump) * NBBY) + bit) * PAGE_SIZE;
  360                         error = blk_write(di, 0, pa, PAGE_SIZE);
  361                         if (error)
  362                                 goto fail;
  363                         bits &= ~(1ul << bit);
  364                 }
  365         }
  366 
  367         error = blk_flush(di);
  368         if (error)
  369                 goto fail;
  370 
  371         /* Dump trailer */
  372         error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
  373         if (error)
  374                 goto fail;
  375         dumplo += sizeof(kdh);
  376 
  377         /* Signal completion, signoff and exit stage left. */
  378         dump_write(di, NULL, 0, 0, 0);
  379         printf("\nDump complete\n");
  380         return;
  381 
  382  fail:
  383         if (error < 0)
  384                 error = -error;
  385 
  386         if (error == ECANCELED)
  387                 printf("\nDump aborted\n");
  388         else if (error == ENOSPC)
  389                 printf("\nDump failed. Partition too small.\n");
  390         else
  391                 printf("\n** DUMP FAILED (ERROR %d) **\n", error);
  392 }
  393 
  394 void
  395 dump_add_page(vm_paddr_t pa)
  396 {
  397         int idx, bit;
  398 
  399         pa >>= PAGE_SHIFT;
  400         idx = pa >> 5;          /* 2^5 = 32 */
  401         bit = pa & 31;
  402         atomic_set_int(&vm_page_dump[idx], 1ul << bit);
  403 }
  404 
  405 void
  406 dump_drop_page(vm_paddr_t pa)
  407 {
  408         int idx, bit;
  409 
  410         pa >>= PAGE_SHIFT;
  411         idx = pa >> 5;          /* 2^5 = 32 */
  412         bit = pa & 31;
  413         atomic_clear_int(&vm_page_dump[idx], 1ul << bit);
  414 }
  415 

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