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/8.0/sys/i386/i386/minidump_machdep.c 193066 2009-05-29 21:27:12Z jamie $");
   29 
   30 #include <sys/param.h>
   31 #include <sys/systm.h>
   32 #include <sys/conf.h>
   33 #include <sys/cons.h>
   34 #include <sys/kernel.h>
   35 #include <sys/kerneldump.h>
   36 #include <sys/msgbuf.h>
   37 #include <vm/vm.h>
   38 #include <vm/pmap.h>
   39 #include <machine/atomic.h>
   40 #include <machine/elf.h>
   41 #include <machine/md_var.h>
   42 #include <machine/vmparam.h>
   43 #include <machine/minidump.h>
   44 
   45 CTASSERT(sizeof(struct kerneldumpheader) == 512);
   46 
   47 /*
   48  * Don't touch the first SIZEOF_METADATA bytes on the dump device. This
   49  * is to protect us from metadata and to protect metadata from us.
   50  */
   51 #define SIZEOF_METADATA         (64*1024)
   52 
   53 #define MD_ALIGN(x)     (((off_t)(x) + PAGE_MASK) & ~PAGE_MASK)
   54 #define DEV_ALIGN(x)    (((off_t)(x) + (DEV_BSIZE-1)) & ~(DEV_BSIZE-1))
   55 
   56 uint32_t *vm_page_dump;
   57 int vm_page_dump_size;
   58 
   59 static struct kerneldumpheader kdh;
   60 static off_t dumplo;
   61 
   62 /* Handle chunked writes. */
   63 static size_t fragsz;
   64 static void *dump_va;
   65 static uint64_t counter, progress;
   66 
   67 CTASSERT(sizeof(*vm_page_dump) == 4);
   68 
   69 static int
   70 is_dumpable(vm_paddr_t pa)
   71 {
   72         int i;
   73 
   74         for (i = 0; dump_avail[i] != 0 || dump_avail[i + 1] != 0; i += 2) {
   75                 if (pa >= dump_avail[i] && pa < dump_avail[i + 1])
   76                         return (1);
   77         }
   78         return (0);
   79 }
   80 
   81 #define PG2MB(pgs) (((pgs) + (1 << 8) - 1) >> 8)
   82 
   83 static int
   84 blk_flush(struct dumperinfo *di)
   85 {
   86         int error;
   87 
   88         if (fragsz == 0)
   89                 return (0);
   90 
   91         error = dump_write(di, dump_va, 0, dumplo, fragsz);
   92         dumplo += fragsz;
   93         fragsz = 0;
   94         return (error);
   95 }
   96 
   97 static int
   98 blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
   99 {
  100         size_t len;
  101         int error, i, c;
  102         u_int maxdumpsz;
  103 
  104         maxdumpsz = min(di->maxiosize, MAXDUMPPGS * PAGE_SIZE);
  105         if (maxdumpsz == 0)     /* seatbelt */
  106                 maxdumpsz = PAGE_SIZE;
  107         error = 0;
  108         if ((sz % PAGE_SIZE) != 0) {
  109                 printf("size not page aligned\n");
  110                 return (EINVAL);
  111         }
  112         if (ptr != NULL && pa != 0) {
  113                 printf("cant have both va and pa!\n");
  114                 return (EINVAL);
  115         }
  116         if (pa != 0 && (((uintptr_t)ptr) % PAGE_SIZE) != 0) {
  117                 printf("address not page aligned\n");
  118                 return (EINVAL);
  119         }
  120         if (ptr != NULL) {
  121                 /* If we're doing a virtual dump, flush any pre-existing pa pages */
  122                 error = blk_flush(di);
  123                 if (error)
  124                         return (error);
  125         }
  126         while (sz) {
  127                 len = maxdumpsz - fragsz;
  128                 if (len > sz)
  129                         len = sz;
  130                 counter += len;
  131                 progress -= len;
  132                 if (counter >> 24) {
  133                         printf(" %lld", PG2MB(progress >> PAGE_SHIFT));
  134                         counter &= (1<<24) - 1;
  135                 }
  136                 if (ptr) {
  137                         error = dump_write(di, ptr, 0, dumplo, len);
  138                         if (error)
  139                                 return (error);
  140                         dumplo += len;
  141                         ptr += len;
  142                         sz -= len;
  143                 } else {
  144                         for (i = 0; i < len; i += PAGE_SIZE)
  145                                 dump_va = pmap_kenter_temporary(pa + i, (i + fragsz) >> PAGE_SHIFT);
  146                         fragsz += len;
  147                         pa += len;
  148                         sz -= len;
  149                         if (fragsz == maxdumpsz) {
  150                                 error = blk_flush(di);
  151                                 if (error)
  152                                         return (error);
  153                         }
  154                 }
  155 
  156                 /* Check for user abort. */
  157                 c = cncheckc();
  158                 if (c == 0x03)
  159                         return (ECANCELED);
  160                 if (c != -1)
  161                         printf(" (CTRL-C to abort) ");
  162         }
  163 
  164         return (0);
  165 }
  166 
  167 /* A fake page table page, to avoid having to handle both 4K and 2M pages */
  168 static pt_entry_t fakept[NPTEPG];
  169 
  170 void
  171 minidumpsys(struct dumperinfo *di)
  172 {
  173         uint64_t dumpsize;
  174         uint32_t ptesize;
  175         vm_offset_t va;
  176         int error;
  177         uint32_t bits;
  178         uint64_t pa;
  179         pd_entry_t *pd;
  180         pt_entry_t *pt;
  181         int i, j, k, bit;
  182         struct minidumphdr mdhdr;
  183 
  184         counter = 0;
  185         /* Walk page table pages, set bits in vm_page_dump */
  186         ptesize = 0;
  187         for (va = KERNBASE; va < kernel_vm_end; va += NBPDR) {
  188                 /*
  189                  * We always write a page, even if it is zero. Each
  190                  * page written corresponds to 2MB of space
  191                  */
  192                 ptesize += PAGE_SIZE;
  193                 pd = (pd_entry_t *)((uintptr_t)IdlePTD + KERNBASE);     /* always mapped! */
  194                 j = va >> PDRSHIFT;
  195                 if ((pd[j] & (PG_PS | PG_V)) == (PG_PS | PG_V))  {
  196                         /* This is an entire 2M page. */
  197                         pa = pd[j] & PG_PS_FRAME;
  198                         for (k = 0; k < NPTEPG; k++) {
  199                                 if (is_dumpable(pa))
  200                                         dump_add_page(pa);
  201                                 pa += PAGE_SIZE;
  202                         }
  203                         continue;
  204                 }
  205                 if ((pd[j] & PG_V) == PG_V) {
  206                         /* set bit for each valid page in this 2MB block */
  207                         pt = pmap_kenter_temporary(pd[j] & PG_FRAME, 0);
  208                         for (k = 0; k < NPTEPG; k++) {
  209                                 if ((pt[k] & PG_V) == PG_V) {
  210                                         pa = pt[k] & PG_FRAME;
  211                                         if (is_dumpable(pa))
  212                                                 dump_add_page(pa);
  213                                 }
  214                         }
  215                 } else {
  216                         /* nothing, we're going to dump a null page */
  217                 }
  218         }
  219 
  220         /* Calculate dump size. */
  221         dumpsize = ptesize;
  222         dumpsize += round_page(msgbufp->msg_size);
  223         dumpsize += round_page(vm_page_dump_size);
  224         for (i = 0; i < vm_page_dump_size / sizeof(*vm_page_dump); i++) {
  225                 bits = vm_page_dump[i];
  226                 while (bits) {
  227                         bit = bsfl(bits);
  228                         pa = (((uint64_t)i * sizeof(*vm_page_dump) * NBBY) + bit) * PAGE_SIZE;
  229                         /* Clear out undumpable pages now if needed */
  230                         if (is_dumpable(pa)) {
  231                                 dumpsize += PAGE_SIZE;
  232                         } else {
  233                                 dump_drop_page(pa);
  234                         }
  235                         bits &= ~(1ul << bit);
  236                 }
  237         }
  238         dumpsize += PAGE_SIZE;
  239 
  240         /* Determine dump offset on device. */
  241         if (di->mediasize < SIZEOF_METADATA + dumpsize + sizeof(kdh) * 2) {
  242                 error = ENOSPC;
  243                 goto fail;
  244         }
  245         dumplo = di->mediaoffset + di->mediasize - dumpsize;
  246         dumplo -= sizeof(kdh) * 2;
  247         progress = dumpsize;
  248 
  249         /* Initialize mdhdr */
  250         bzero(&mdhdr, sizeof(mdhdr));
  251         strcpy(mdhdr.magic, MINIDUMP_MAGIC);
  252         mdhdr.version = MINIDUMP_VERSION;
  253         mdhdr.msgbufsize = msgbufp->msg_size;
  254         mdhdr.bitmapsize = vm_page_dump_size;
  255         mdhdr.ptesize = ptesize;
  256         mdhdr.kernbase = KERNBASE;
  257 #ifdef PAE
  258         mdhdr.paemode = 1;
  259 #endif
  260 
  261         mkdumpheader(&kdh, KERNELDUMPMAGIC, KERNELDUMP_I386_VERSION, dumpsize, di->blocksize);
  262 
  263         printf("Physical memory: %ju MB\n", ptoa((uintmax_t)physmem) / 1048576);
  264         printf("Dumping %llu MB:", (long long)dumpsize >> 20);
  265 
  266         /* Dump leader */
  267         error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
  268         if (error)
  269                 goto fail;
  270         dumplo += sizeof(kdh);
  271 
  272         /* Dump my header */
  273         bzero(&fakept, sizeof(fakept));
  274         bcopy(&mdhdr, &fakept, sizeof(mdhdr));
  275         error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
  276         if (error)
  277                 goto fail;
  278 
  279         /* Dump msgbuf up front */
  280         error = blk_write(di, (char *)msgbufp->msg_ptr, 0, round_page(msgbufp->msg_size));
  281         if (error)
  282                 goto fail;
  283 
  284         /* Dump bitmap */
  285         error = blk_write(di, (char *)vm_page_dump, 0, round_page(vm_page_dump_size));
  286         if (error)
  287                 goto fail;
  288 
  289         /* Dump kernel page table pages */
  290         for (va = KERNBASE; va < kernel_vm_end; va += NBPDR) {
  291                 /* We always write a page, even if it is zero */
  292                 pd = (pd_entry_t *)((uintptr_t)IdlePTD + KERNBASE);     /* always mapped! */
  293                 j = va >> PDRSHIFT;
  294                 if ((pd[j] & (PG_PS | PG_V)) == (PG_PS | PG_V))  {
  295                         /* This is a single 2M block. Generate a fake PTP */
  296                         pa = pd[j] & PG_PS_FRAME;
  297                         for (k = 0; k < NPTEPG; k++) {
  298                                 fakept[k] = (pa + (k * PAGE_SIZE)) | PG_V | PG_RW | PG_A | PG_M;
  299                         }
  300                         error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
  301                         if (error)
  302                                 goto fail;
  303                         /* flush, in case we reuse fakept in the same block */
  304                         error = blk_flush(di);
  305                         if (error)
  306                                 goto fail;
  307                         continue;
  308                 }
  309                 if ((pd[j] & PG_V) == PG_V) {
  310                         pa = pd[j] & PG_FRAME;
  311                         error = blk_write(di, 0, pa, PAGE_SIZE);
  312                         if (error)
  313                                 goto fail;
  314                 } else {
  315                         bzero(fakept, sizeof(fakept));
  316                         error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
  317                         if (error)
  318                                 goto fail;
  319                         /* flush, in case we reuse fakept in the same block */
  320                         error = blk_flush(di);
  321                         if (error)
  322                                 goto fail;
  323                 }
  324         }
  325 
  326         /* Dump memory chunks */
  327         /* XXX cluster it up and use blk_dump() */
  328         for (i = 0; i < vm_page_dump_size / sizeof(*vm_page_dump); i++) {
  329                 bits = vm_page_dump[i];
  330                 while (bits) {
  331                         bit = bsfl(bits);
  332                         pa = (((uint64_t)i * sizeof(*vm_page_dump) * NBBY) + bit) * PAGE_SIZE;
  333                         error = blk_write(di, 0, pa, PAGE_SIZE);
  334                         if (error)
  335                                 goto fail;
  336                         bits &= ~(1ul << bit);
  337                 }
  338         }
  339 
  340         error = blk_flush(di);
  341         if (error)
  342                 goto fail;
  343 
  344         /* Dump trailer */
  345         error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
  346         if (error)
  347                 goto fail;
  348         dumplo += sizeof(kdh);
  349 
  350         /* Signal completion, signoff and exit stage left. */
  351         dump_write(di, NULL, 0, 0, 0);
  352         printf("\nDump complete\n");
  353         return;
  354 
  355  fail:
  356         if (error < 0)
  357                 error = -error;
  358 
  359         if (error == ECANCELED)
  360                 printf("\nDump aborted\n");
  361         else if (error == ENOSPC)
  362                 printf("\nDump failed. Partition too small.\n");
  363         else
  364                 printf("\n** DUMP FAILED (ERROR %d) **\n", error);
  365 }
  366 
  367 void
  368 dump_add_page(vm_paddr_t pa)
  369 {
  370         int idx, bit;
  371 
  372         pa >>= PAGE_SHIFT;
  373         idx = pa >> 5;          /* 2^5 = 32 */
  374         bit = pa & 31;
  375         atomic_set_int(&vm_page_dump[idx], 1ul << bit);
  376 }
  377 
  378 void
  379 dump_drop_page(vm_paddr_t pa)
  380 {
  381         int idx, bit;
  382 
  383         pa >>= PAGE_SHIFT;
  384         idx = pa >> 5;          /* 2^5 = 32 */
  385         bit = pa & 31;
  386         atomic_clear_int(&vm_page_dump[idx], 1ul << bit);
  387 }
  388 

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