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/amd64/amd64/minidump_machdep.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2006 Peter Wemm
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  *
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   27  */
   28 
   29 #include <sys/cdefs.h>
   30 __FBSDID("$FreeBSD: releng/12.0/sys/amd64/amd64/minidump_machdep.c 333145 2018-05-01 17:32:43Z markj $");
   31 
   32 #include "opt_pmap.h"
   33 #include "opt_watchdog.h"
   34 
   35 #include <sys/param.h>
   36 #include <sys/systm.h>
   37 #include <sys/conf.h>
   38 #include <sys/cons.h>
   39 #include <sys/kernel.h>
   40 #include <sys/kerneldump.h>
   41 #include <sys/msgbuf.h>
   42 #include <sys/sysctl.h>
   43 #include <sys/watchdog.h>
   44 #include <sys/vmmeter.h>
   45 #include <vm/vm.h>
   46 #include <vm/vm_param.h>
   47 #include <vm/vm_page.h>
   48 #include <vm/vm_phys.h>
   49 #include <vm/pmap.h>
   50 #include <machine/atomic.h>
   51 #include <machine/elf.h>
   52 #include <machine/md_var.h>
   53 #include <machine/minidump.h>
   54 
   55 CTASSERT(sizeof(struct kerneldumpheader) == 512);
   56 
   57 uint64_t *vm_page_dump;
   58 int vm_page_dump_size;
   59 
   60 static struct kerneldumpheader kdh;
   61 
   62 /* Handle chunked writes. */
   63 static size_t fragsz;
   64 static void *dump_va;
   65 static size_t counter, progress, dumpsize, wdog_next;
   66 
   67 CTASSERT(sizeof(*vm_page_dump) == 8);
   68 static int dump_retry_count = 5;
   69 SYSCTL_INT(_machdep, OID_AUTO, dump_retry_count, CTLFLAG_RWTUN,
   70     &dump_retry_count, 0, "Number of times dump has to retry before bailing out");
   71 
   72 static int
   73 is_dumpable(vm_paddr_t pa)
   74 {
   75         vm_page_t m;
   76         int i;
   77 
   78         if ((m = vm_phys_paddr_to_vm_page(pa)) != NULL)
   79                 return ((m->flags & PG_NODUMP) == 0);
   80         for (i = 0; dump_avail[i] != 0 || dump_avail[i + 1] != 0; i += 2) {
   81                 if (pa >= dump_avail[i] && pa < dump_avail[i + 1])
   82                         return (1);
   83         }
   84         return (0);
   85 }
   86 
   87 #define PG2MB(pgs) (((pgs) + (1 << 8) - 1) >> 8)
   88 
   89 static int
   90 blk_flush(struct dumperinfo *di)
   91 {
   92         int error;
   93 
   94         if (fragsz == 0)
   95                 return (0);
   96 
   97         error = dump_append(di, dump_va, 0, fragsz);
   98         fragsz = 0;
   99         return (error);
  100 }
  101 
  102 static struct {
  103         int min_per;
  104         int max_per;
  105         int visited;
  106 } progress_track[10] = {
  107         {  0,  10, 0},
  108         { 10,  20, 0},
  109         { 20,  30, 0},
  110         { 30,  40, 0},
  111         { 40,  50, 0},
  112         { 50,  60, 0},
  113         { 60,  70, 0},
  114         { 70,  80, 0},
  115         { 80,  90, 0},
  116         { 90, 100, 0}
  117 };
  118 
  119 static void
  120 report_progress(size_t progress, size_t dumpsize)
  121 {
  122         int sofar, i;
  123 
  124         sofar = 100 - ((progress * 100) / dumpsize);
  125         for (i = 0; i < nitems(progress_track); i++) {
  126                 if (sofar < progress_track[i].min_per ||
  127                     sofar > progress_track[i].max_per)
  128                         continue;
  129                 if (progress_track[i].visited)
  130                         return;
  131                 progress_track[i].visited = 1;
  132                 printf("..%d%%", sofar);
  133                 return;
  134         }
  135 }
  136 
  137 /* Pat the watchdog approximately every 128MB of the dump. */
  138 #define WDOG_DUMP_INTERVAL      (128 * 1024 * 1024)
  139 
  140 static int
  141 blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
  142 {
  143         size_t len;
  144         int error, i, c;
  145         u_int maxdumpsz;
  146 
  147         maxdumpsz = min(di->maxiosize, MAXDUMPPGS * PAGE_SIZE);
  148         if (maxdumpsz == 0)     /* seatbelt */
  149                 maxdumpsz = PAGE_SIZE;
  150         error = 0;
  151         if ((sz % PAGE_SIZE) != 0) {
  152                 printf("size not page aligned\n");
  153                 return (EINVAL);
  154         }
  155         if (ptr != NULL && pa != 0) {
  156                 printf("cant have both va and pa!\n");
  157                 return (EINVAL);
  158         }
  159         if ((((uintptr_t)pa) % PAGE_SIZE) != 0) {
  160                 printf("address not page aligned %p\n", ptr);
  161                 return (EINVAL);
  162         }
  163         if (ptr != NULL) {
  164                 /* If we're doing a virtual dump, flush any pre-existing pa pages */
  165                 error = blk_flush(di);
  166                 if (error)
  167                         return (error);
  168         }
  169         while (sz) {
  170                 len = maxdumpsz - fragsz;
  171                 if (len > sz)
  172                         len = sz;
  173                 counter += len;
  174                 progress -= len;
  175                 if (counter >> 24) {
  176                         report_progress(progress, dumpsize);
  177                         counter &= (1<<24) - 1;
  178                 }
  179                 if (progress <= wdog_next) {
  180                         wdog_kern_pat(WD_LASTVAL);
  181                         if (wdog_next > WDOG_DUMP_INTERVAL)
  182                                 wdog_next -= WDOG_DUMP_INTERVAL;
  183                         else
  184                                 wdog_next = 0;
  185                 }
  186 
  187                 if (ptr) {
  188                         error = dump_append(di, ptr, 0, len);
  189                         if (error)
  190                                 return (error);
  191                         ptr += len;
  192                         sz -= len;
  193                 } else {
  194                         for (i = 0; i < len; i += PAGE_SIZE)
  195                                 dump_va = pmap_kenter_temporary(pa + i, (i + fragsz) >> PAGE_SHIFT);
  196                         fragsz += len;
  197                         pa += len;
  198                         sz -= len;
  199                         if (fragsz == maxdumpsz) {
  200                                 error = blk_flush(di);
  201                                 if (error)
  202                                         return (error);
  203                         }
  204                 }
  205 
  206                 /* Check for user abort. */
  207                 c = cncheckc();
  208                 if (c == 0x03)
  209                         return (ECANCELED);
  210                 if (c != -1)
  211                         printf(" (CTRL-C to abort) ");
  212         }
  213 
  214         return (0);
  215 }
  216 
  217 /* A fake page table page, to avoid having to handle both 4K and 2M pages */
  218 static pd_entry_t fakepd[NPDEPG];
  219 
  220 int
  221 minidumpsys(struct dumperinfo *di)
  222 {
  223         uint32_t pmapsize;
  224         vm_offset_t va;
  225         int error;
  226         uint64_t bits;
  227         uint64_t *pml4, *pdp, *pd, *pt, pa;
  228         int i, ii, j, k, n, bit;
  229         int retry_count;
  230         struct minidumphdr mdhdr;
  231 
  232         retry_count = 0;
  233  retry:
  234         retry_count++;
  235         counter = 0;
  236         for (i = 0; i < nitems(progress_track); i++)
  237                 progress_track[i].visited = 0;
  238         /* Walk page table pages, set bits in vm_page_dump */
  239         pmapsize = 0;
  240         for (va = VM_MIN_KERNEL_ADDRESS; va < MAX(KERNBASE + nkpt * NBPDR,
  241             kernel_vm_end); ) {
  242                 /*
  243                  * We always write a page, even if it is zero. Each
  244                  * page written corresponds to 1GB of space
  245                  */
  246                 pmapsize += PAGE_SIZE;
  247                 ii = pmap_pml4e_index(va);
  248                 pml4 = (uint64_t *)PHYS_TO_DMAP(KPML4phys) + ii;
  249                 pdp = (uint64_t *)PHYS_TO_DMAP(*pml4 & PG_FRAME);
  250                 i = pmap_pdpe_index(va);
  251                 if ((pdp[i] & PG_V) == 0) {
  252                         va += NBPDP;
  253                         continue;
  254                 }
  255 
  256                 /*
  257                  * 1GB page is represented as 512 2MB pages in a dump.
  258                  */
  259                 if ((pdp[i] & PG_PS) != 0) {
  260                         va += NBPDP;
  261                         pa = pdp[i] & PG_PS_FRAME;
  262                         for (n = 0; n < NPDEPG * NPTEPG; n++) {
  263                                 if (is_dumpable(pa))
  264                                         dump_add_page(pa);
  265                                 pa += PAGE_SIZE;
  266                         }
  267                         continue;
  268                 }
  269 
  270                 pd = (uint64_t *)PHYS_TO_DMAP(pdp[i] & PG_FRAME);
  271                 for (n = 0; n < NPDEPG; n++, va += NBPDR) {
  272                         j = pmap_pde_index(va);
  273 
  274                         if ((pd[j] & PG_V) == 0)
  275                                 continue;
  276 
  277                         if ((pd[j] & PG_PS) != 0) {
  278                                 /* This is an entire 2M page. */
  279                                 pa = pd[j] & PG_PS_FRAME;
  280                                 for (k = 0; k < NPTEPG; k++) {
  281                                         if (is_dumpable(pa))
  282                                                 dump_add_page(pa);
  283                                         pa += PAGE_SIZE;
  284                                 }
  285                                 continue;
  286                         }
  287 
  288                         pa = pd[j] & PG_FRAME;
  289                         /* set bit for this PTE page */
  290                         if (is_dumpable(pa))
  291                                 dump_add_page(pa);
  292                         /* and for each valid page in this 2MB block */
  293                         pt = (uint64_t *)PHYS_TO_DMAP(pd[j] & PG_FRAME);
  294                         for (k = 0; k < NPTEPG; k++) {
  295                                 if ((pt[k] & PG_V) == 0)
  296                                         continue;
  297                                 pa = pt[k] & PG_FRAME;
  298                                 if (is_dumpable(pa))
  299                                         dump_add_page(pa);
  300                         }
  301                 }
  302         }
  303 
  304         /* Calculate dump size. */
  305         dumpsize = pmapsize;
  306         dumpsize += round_page(msgbufp->msg_size);
  307         dumpsize += round_page(vm_page_dump_size);
  308         for (i = 0; i < vm_page_dump_size / sizeof(*vm_page_dump); i++) {
  309                 bits = vm_page_dump[i];
  310                 while (bits) {
  311                         bit = bsfq(bits);
  312                         pa = (((uint64_t)i * sizeof(*vm_page_dump) * NBBY) + bit) * PAGE_SIZE;
  313                         /* Clear out undumpable pages now if needed */
  314                         if (is_dumpable(pa)) {
  315                                 dumpsize += PAGE_SIZE;
  316                         } else {
  317                                 dump_drop_page(pa);
  318                         }
  319                         bits &= ~(1ul << bit);
  320                 }
  321         }
  322         dumpsize += PAGE_SIZE;
  323 
  324         wdog_next = progress = dumpsize;
  325 
  326         /* Initialize mdhdr */
  327         bzero(&mdhdr, sizeof(mdhdr));
  328         strcpy(mdhdr.magic, MINIDUMP_MAGIC);
  329         mdhdr.version = MINIDUMP_VERSION;
  330         mdhdr.msgbufsize = msgbufp->msg_size;
  331         mdhdr.bitmapsize = vm_page_dump_size;
  332         mdhdr.pmapsize = pmapsize;
  333         mdhdr.kernbase = VM_MIN_KERNEL_ADDRESS;
  334         mdhdr.dmapbase = DMAP_MIN_ADDRESS;
  335         mdhdr.dmapend = DMAP_MAX_ADDRESS;
  336 
  337         dump_init_header(di, &kdh, KERNELDUMPMAGIC, KERNELDUMP_AMD64_VERSION,
  338             dumpsize);
  339 
  340         error = dump_start(di, &kdh);
  341         if (error != 0)
  342                 goto fail;
  343 
  344         printf("Dumping %llu out of %ju MB:", (long long)dumpsize >> 20,
  345             ptoa((uintmax_t)physmem) / 1048576);
  346 
  347         /* Dump my header */
  348         bzero(&fakepd, sizeof(fakepd));
  349         bcopy(&mdhdr, &fakepd, sizeof(mdhdr));
  350         error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE);
  351         if (error)
  352                 goto fail;
  353 
  354         /* Dump msgbuf up front */
  355         error = blk_write(di, (char *)msgbufp->msg_ptr, 0, round_page(msgbufp->msg_size));
  356         if (error)
  357                 goto fail;
  358 
  359         /* Dump bitmap */
  360         error = blk_write(di, (char *)vm_page_dump, 0, round_page(vm_page_dump_size));
  361         if (error)
  362                 goto fail;
  363 
  364         /* Dump kernel page directory pages */
  365         bzero(fakepd, sizeof(fakepd));
  366         for (va = VM_MIN_KERNEL_ADDRESS; va < MAX(KERNBASE + nkpt * NBPDR,
  367             kernel_vm_end); va += NBPDP) {
  368                 ii = pmap_pml4e_index(va);
  369                 pml4 = (uint64_t *)PHYS_TO_DMAP(KPML4phys) + ii;
  370                 pdp = (uint64_t *)PHYS_TO_DMAP(*pml4 & PG_FRAME);
  371                 i = pmap_pdpe_index(va);
  372 
  373                 /* We always write a page, even if it is zero */
  374                 if ((pdp[i] & PG_V) == 0) {
  375                         error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE);
  376                         if (error)
  377                                 goto fail;
  378                         /* flush, in case we reuse fakepd in the same block */
  379                         error = blk_flush(di);
  380                         if (error)
  381                                 goto fail;
  382                         continue;
  383                 }
  384 
  385                 /* 1GB page is represented as 512 2MB pages in a dump */
  386                 if ((pdp[i] & PG_PS) != 0) {
  387                         /* PDPE and PDP have identical layout in this case */
  388                         fakepd[0] = pdp[i];
  389                         for (j = 1; j < NPDEPG; j++)
  390                                 fakepd[j] = fakepd[j - 1] + NBPDR;
  391                         error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE);
  392                         if (error)
  393                                 goto fail;
  394                         /* flush, in case we reuse fakepd in the same block */
  395                         error = blk_flush(di);
  396                         if (error)
  397                                 goto fail;
  398                         bzero(fakepd, sizeof(fakepd));
  399                         continue;
  400                 }
  401 
  402                 pd = (uint64_t *)PHYS_TO_DMAP(pdp[i] & PG_FRAME);
  403                 error = blk_write(di, (char *)pd, 0, PAGE_SIZE);
  404                 if (error)
  405                         goto fail;
  406                 error = blk_flush(di);
  407                 if (error)
  408                         goto fail;
  409         }
  410 
  411         /* Dump memory chunks */
  412         /* XXX cluster it up and use blk_dump() */
  413         for (i = 0; i < vm_page_dump_size / sizeof(*vm_page_dump); i++) {
  414                 bits = vm_page_dump[i];
  415                 while (bits) {
  416                         bit = bsfq(bits);
  417                         pa = (((uint64_t)i * sizeof(*vm_page_dump) * NBBY) + bit) * PAGE_SIZE;
  418                         error = blk_write(di, 0, pa, PAGE_SIZE);
  419                         if (error)
  420                                 goto fail;
  421                         bits &= ~(1ul << bit);
  422                 }
  423         }
  424 
  425         error = blk_flush(di);
  426         if (error)
  427                 goto fail;
  428 
  429         error = dump_finish(di, &kdh);
  430         if (error != 0)
  431                 goto fail;
  432 
  433         printf("\nDump complete\n");
  434         return (0);
  435 
  436  fail:
  437         if (error < 0)
  438                 error = -error;
  439 
  440         printf("\n");
  441         if (error == ENOSPC) {
  442                 printf("Dump map grown while dumping. ");
  443                 if (retry_count < dump_retry_count) {
  444                         printf("Retrying...\n");
  445                         goto retry;
  446                 }
  447                 printf("Dump failed.\n");
  448         }
  449         else if (error == ECANCELED)
  450                 printf("Dump aborted\n");
  451         else if (error == E2BIG)
  452                 printf("Dump failed. Partition too small.\n");
  453         else
  454                 printf("** DUMP FAILED (ERROR %d) **\n", error);
  455         return (error);
  456 }
  457 
  458 void
  459 dump_add_page(vm_paddr_t pa)
  460 {
  461         int idx, bit;
  462 
  463         pa >>= PAGE_SHIFT;
  464         idx = pa >> 6;          /* 2^6 = 64 */
  465         bit = pa & 63;
  466         atomic_set_long(&vm_page_dump[idx], 1ul << bit);
  467 }
  468 
  469 void
  470 dump_drop_page(vm_paddr_t pa)
  471 {
  472         int idx, bit;
  473 
  474         pa >>= PAGE_SHIFT;
  475         idx = pa >> 6;          /* 2^6 = 64 */
  476         bit = pa & 63;
  477         atomic_clear_long(&vm_page_dump[idx], 1ul << bit);
  478 }

Cache object: 40b182f34f2ae5909a00c7f96b65889b


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