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/x86/x86/dump_machdep.c

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    1 /*-
    2  * Copyright (c) 2002 Marcel Moolenaar
    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("$FreeBSD$");
   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/sysctl.h>
   37 #include <sys/kernel.h>
   38 #include <sys/kerneldump.h>
   39 #include <sys/watchdog.h>
   40 #include <vm/vm.h>
   41 #include <vm/pmap.h>
   42 #include <machine/elf.h>
   43 #include <machine/md_var.h>
   44 
   45 #ifdef __amd64__
   46 #define KERNELDUMP_VERSION      KERNELDUMP_AMD64_VERSION
   47 #define EM_VALUE                EM_X86_64
   48 #else
   49 #define KERNELDUMP_VERSION      KERNELDUMP_I386_VERSION
   50 #define EM_VALUE                EM_386
   51 #endif
   52 
   53 CTASSERT(sizeof(struct kerneldumpheader) == 512);
   54 
   55 int do_minidump = 1;
   56 TUNABLE_INT("debug.minidump", &do_minidump);
   57 SYSCTL_INT(_debug, OID_AUTO, minidump, CTLFLAG_RW, &do_minidump, 0,
   58     "Enable mini crash dumps");
   59 
   60 /*
   61  * Don't touch the first SIZEOF_METADATA bytes on the dump device. This
   62  * is to protect us from metadata and to protect metadata from us.
   63  */
   64 #define SIZEOF_METADATA         (64*1024)
   65 
   66 #define MD_ALIGN(x)     (((off_t)(x) + PAGE_MASK) & ~PAGE_MASK)
   67 #define DEV_ALIGN(x)    (((off_t)(x) + (DEV_BSIZE-1)) & ~(DEV_BSIZE-1))
   68 
   69 struct md_pa {
   70         vm_paddr_t md_start;
   71         vm_paddr_t md_size;
   72 };
   73 
   74 typedef int callback_t(struct md_pa *, int, void *);
   75 
   76 static struct kerneldumpheader kdh;
   77 static off_t dumplo, fileofs;
   78 
   79 /* Handle buffered writes. */
   80 static char buffer[DEV_BSIZE];
   81 static size_t fragsz;
   82 
   83 /* 20 phys_avail entry pairs correspond to 10 md_pa's */
   84 static struct md_pa dump_map[10];
   85 
   86 static void
   87 md_pa_init(void)
   88 {
   89         int n, idx;
   90 
   91         bzero(dump_map, sizeof(dump_map));
   92         for (n = 0; n < sizeof(dump_map) / sizeof(dump_map[0]); n++) {
   93                 idx = n * 2;
   94                 if (dump_avail[idx] == 0 && dump_avail[idx + 1] == 0)
   95                         break;
   96                 dump_map[n].md_start = dump_avail[idx];
   97                 dump_map[n].md_size = dump_avail[idx + 1] - dump_avail[idx];
   98         }
   99 }
  100 
  101 static struct md_pa *
  102 md_pa_first(void)
  103 {
  104 
  105         return (&dump_map[0]);
  106 }
  107 
  108 static struct md_pa *
  109 md_pa_next(struct md_pa *mdp)
  110 {
  111 
  112         mdp++;
  113         if (mdp->md_size == 0)
  114                 mdp = NULL;
  115         return (mdp);
  116 }
  117 
  118 static int
  119 buf_write(struct dumperinfo *di, char *ptr, size_t sz)
  120 {
  121         size_t len;
  122         int error;
  123 
  124         while (sz) {
  125                 len = DEV_BSIZE - fragsz;
  126                 if (len > sz)
  127                         len = sz;
  128                 bcopy(ptr, buffer + fragsz, len);
  129                 fragsz += len;
  130                 ptr += len;
  131                 sz -= len;
  132                 if (fragsz == DEV_BSIZE) {
  133                         error = dump_write(di, buffer, 0, dumplo,
  134                             DEV_BSIZE);
  135                         if (error)
  136                                 return error;
  137                         dumplo += DEV_BSIZE;
  138                         fragsz = 0;
  139                 }
  140         }
  141 
  142         return (0);
  143 }
  144 
  145 static int
  146 buf_flush(struct dumperinfo *di)
  147 {
  148         int error;
  149 
  150         if (fragsz == 0)
  151                 return (0);
  152 
  153         error = dump_write(di, buffer, 0, dumplo, DEV_BSIZE);
  154         dumplo += DEV_BSIZE;
  155         fragsz = 0;
  156         return (error);
  157 }
  158 
  159 #define PG2MB(pgs) ((pgs + (1 << 8) - 1) >> 8)
  160 
  161 static int
  162 cb_dumpdata(struct md_pa *mdp, int seqnr, void *arg)
  163 {
  164         struct dumperinfo *di = (struct dumperinfo*)arg;
  165         vm_paddr_t a, pa;
  166         void *va;
  167         uint64_t pgs;
  168         size_t counter, sz, chunk;
  169         int i, c, error, twiddle;
  170         u_int maxdumppgs;
  171 
  172         error = 0;      /* catch case in which chunk size is 0 */
  173         counter = 0;    /* Update twiddle every 16MB */
  174         twiddle = 0;
  175         va = 0;
  176         pgs = mdp->md_size / PAGE_SIZE;
  177         pa = mdp->md_start;
  178         maxdumppgs = min(di->maxiosize / PAGE_SIZE, MAXDUMPPGS);
  179         if (maxdumppgs == 0)    /* seatbelt */
  180                 maxdumppgs = 1;
  181 
  182         printf("  chunk %d: %juMB (%ju pages)", seqnr, (uintmax_t)PG2MB(pgs),
  183             (uintmax_t)pgs);
  184 
  185         while (pgs) {
  186                 chunk = pgs;
  187                 if (chunk > maxdumppgs)
  188                         chunk = maxdumppgs;
  189                 sz = chunk << PAGE_SHIFT;
  190                 counter += sz;
  191                 if (counter >> 24) {
  192                         printf(" %ju", (uintmax_t)PG2MB(pgs));
  193                         counter &= (1<<24) - 1;
  194                 }
  195                 for (i = 0; i < chunk; i++) {
  196                         a = pa + i * PAGE_SIZE;
  197                         va = pmap_kenter_temporary(trunc_page(a), i);
  198                 }
  199 
  200                 wdog_kern_pat(WD_LASTVAL);
  201 
  202                 error = dump_write(di, va, 0, dumplo, sz);
  203                 if (error)
  204                         break;
  205                 dumplo += sz;
  206                 pgs -= chunk;
  207                 pa += sz;
  208 
  209                 /* Check for user abort. */
  210                 c = cncheckc();
  211                 if (c == 0x03)
  212                         return (ECANCELED);
  213                 if (c != -1)
  214                         printf(" (CTRL-C to abort) ");
  215         }
  216         printf(" ... %s\n", (error) ? "fail" : "ok");
  217         return (error);
  218 }
  219 
  220 static int
  221 cb_dumphdr(struct md_pa *mdp, int seqnr, void *arg)
  222 {
  223         struct dumperinfo *di = (struct dumperinfo*)arg;
  224         Elf_Phdr phdr;
  225         uint64_t size;
  226         int error;
  227 
  228         size = mdp->md_size;
  229         bzero(&phdr, sizeof(phdr));
  230         phdr.p_type = PT_LOAD;
  231         phdr.p_flags = PF_R;                    /* XXX */
  232         phdr.p_offset = fileofs;
  233         phdr.p_vaddr = mdp->md_start;
  234         phdr.p_paddr = mdp->md_start;
  235         phdr.p_filesz = size;
  236         phdr.p_memsz = size;
  237         phdr.p_align = PAGE_SIZE;
  238 
  239         error = buf_write(di, (char*)&phdr, sizeof(phdr));
  240         fileofs += phdr.p_filesz;
  241         return (error);
  242 }
  243 
  244 static int
  245 cb_size(struct md_pa *mdp, int seqnr, void *arg)
  246 {
  247         uint64_t *sz = (uint64_t*)arg;
  248 
  249         *sz += (uint64_t)mdp->md_size;
  250         return (0);
  251 }
  252 
  253 static int
  254 foreach_chunk(callback_t cb, void *arg)
  255 {
  256         struct md_pa *mdp;
  257         int error, seqnr;
  258 
  259         seqnr = 0;
  260         mdp = md_pa_first();
  261         while (mdp != NULL) {
  262                 error = (*cb)(mdp, seqnr++, arg);
  263                 if (error)
  264                         return (-error);
  265                 mdp = md_pa_next(mdp);
  266         }
  267         return (seqnr);
  268 }
  269 
  270 void
  271 dumpsys(struct dumperinfo *di)
  272 {
  273         Elf_Ehdr ehdr;
  274         uint64_t dumpsize;
  275         off_t hdrgap;
  276         size_t hdrsz;
  277         int error;
  278 
  279         if (do_minidump) {
  280                 minidumpsys(di);
  281                 return;
  282         }
  283         bzero(&ehdr, sizeof(ehdr));
  284         ehdr.e_ident[EI_MAG0] = ELFMAG0;
  285         ehdr.e_ident[EI_MAG1] = ELFMAG1;
  286         ehdr.e_ident[EI_MAG2] = ELFMAG2;
  287         ehdr.e_ident[EI_MAG3] = ELFMAG3;
  288         ehdr.e_ident[EI_CLASS] = ELF_CLASS;
  289 #if BYTE_ORDER == LITTLE_ENDIAN
  290         ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
  291 #else
  292         ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
  293 #endif
  294         ehdr.e_ident[EI_VERSION] = EV_CURRENT;
  295         ehdr.e_ident[EI_OSABI] = ELFOSABI_STANDALONE;   /* XXX big picture? */
  296         ehdr.e_type = ET_CORE;
  297         ehdr.e_machine = EM_VALUE;
  298         ehdr.e_phoff = sizeof(ehdr);
  299         ehdr.e_flags = 0;
  300         ehdr.e_ehsize = sizeof(ehdr);
  301         ehdr.e_phentsize = sizeof(Elf_Phdr);
  302         ehdr.e_shentsize = sizeof(Elf_Shdr);
  303 
  304         md_pa_init();
  305 
  306         /* Calculate dump size. */
  307         dumpsize = 0L;
  308         ehdr.e_phnum = foreach_chunk(cb_size, &dumpsize);
  309         hdrsz = ehdr.e_phoff + ehdr.e_phnum * ehdr.e_phentsize;
  310         fileofs = MD_ALIGN(hdrsz);
  311         dumpsize += fileofs;
  312         hdrgap = fileofs - DEV_ALIGN(hdrsz);
  313 
  314         /* Determine dump offset on device. */
  315         if (di->mediasize < SIZEOF_METADATA + dumpsize + sizeof(kdh) * 2) {
  316                 error = ENOSPC;
  317                 goto fail;
  318         }
  319         dumplo = di->mediaoffset + di->mediasize - dumpsize;
  320         dumplo -= sizeof(kdh) * 2;
  321 
  322         mkdumpheader(&kdh, KERNELDUMPMAGIC, KERNELDUMP_VERSION, dumpsize,
  323             di->blocksize);
  324 
  325         printf("Dumping %llu MB (%d chunks)\n", (long long)dumpsize >> 20,
  326             ehdr.e_phnum);
  327 
  328         /* Dump leader */
  329         error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
  330         if (error)
  331                 goto fail;
  332         dumplo += sizeof(kdh);
  333 
  334         /* Dump ELF header */
  335         error = buf_write(di, (char*)&ehdr, sizeof(ehdr));
  336         if (error)
  337                 goto fail;
  338 
  339         /* Dump program headers */
  340         error = foreach_chunk(cb_dumphdr, di);
  341         if (error < 0)
  342                 goto fail;
  343         buf_flush(di);
  344 
  345         /*
  346          * All headers are written using blocked I/O, so we know the
  347          * current offset is (still) block aligned. Skip the alignement
  348          * in the file to have the segment contents aligned at page
  349          * boundary. We cannot use MD_ALIGN on dumplo, because we don't
  350          * care and may very well be unaligned within the dump device.
  351          */
  352         dumplo += hdrgap;
  353 
  354         /* Dump memory chunks (updates dumplo) */
  355         error = foreach_chunk(cb_dumpdata, di);
  356         if (error < 0)
  357                 goto fail;
  358 
  359         /* Dump trailer */
  360         error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
  361         if (error)
  362                 goto fail;
  363 
  364         /* Signal completion, signoff and exit stage left. */
  365         dump_write(di, NULL, 0, 0, 0);
  366         printf("\nDump complete\n");
  367         return;
  368 
  369  fail:
  370         if (error < 0)
  371                 error = -error;
  372 
  373         if (error == ECANCELED)
  374                 printf("\nDump aborted\n");
  375         else if (error == ENOSPC)
  376                 printf("\nDump failed. Partition too small.\n");
  377         else
  378                 printf("\n** DUMP FAILED (ERROR %d) **\n", error);
  379 }

Cache object: 6092a73e25f6bae52134ee80d906a521


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