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/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 <sys/param.h>
   31 #include <sys/systm.h>
   32 #include <sys/conf.h>
   33 #include <sys/cons.h>
   34 #include <sys/sysctl.h>
   35 #include <sys/kernel.h>
   36 #include <sys/kerneldump.h>
   37 #include <vm/vm.h>
   38 #include <vm/pmap.h>
   39 #include <machine/elf.h>
   40 #include <machine/md_var.h>
   41 
   42 CTASSERT(sizeof(struct kerneldumpheader) == 512);
   43 
   44 int do_minidump = 1;
   45 TUNABLE_INT("debug.minidump", &do_minidump);
   46 SYSCTL_INT(_debug, OID_AUTO, minidump, CTLFLAG_RW, &do_minidump, 0,
   47     "Enable mini crash dumps");
   48 
   49 /*
   50  * Don't touch the first SIZEOF_METADATA bytes on the dump device. This
   51  * is to protect us from metadata and to protect metadata from us.
   52  */
   53 #define SIZEOF_METADATA         (64*1024)
   54 
   55 #define MD_ALIGN(x)     (((off_t)(x) + PAGE_MASK) & ~PAGE_MASK)
   56 #define DEV_ALIGN(x)    (((off_t)(x) + (DEV_BSIZE-1)) & ~(DEV_BSIZE-1))
   57 
   58 struct md_pa {
   59         vm_paddr_t md_start;
   60         vm_paddr_t md_size;
   61 };
   62 
   63 typedef int callback_t(struct md_pa *, int, void *);
   64 
   65 static struct kerneldumpheader kdh;
   66 static off_t dumplo, fileofs;
   67 
   68 /* Handle buffered writes. */
   69 static char buffer[DEV_BSIZE];
   70 static size_t fragsz;
   71 
   72 /* 20 phys_avail entry pairs correspond to 10 md_pa's */
   73 static struct md_pa dump_map[10];
   74 
   75 static void
   76 md_pa_init(void)
   77 {
   78         int n, idx;
   79 
   80         bzero(dump_map, sizeof(dump_map));
   81         for (n = 0; n < sizeof(dump_map) / sizeof(dump_map[0]); n++) {
   82                 idx = n * 2;
   83                 if (dump_avail[idx] == 0 && dump_avail[idx + 1] == 0)
   84                         break;
   85                 dump_map[n].md_start = dump_avail[idx];
   86                 dump_map[n].md_size = dump_avail[idx + 1] - dump_avail[idx];
   87         }
   88 }
   89 
   90 static struct md_pa *
   91 md_pa_first(void)
   92 {
   93 
   94         return (&dump_map[0]);
   95 }
   96 
   97 static struct md_pa *
   98 md_pa_next(struct md_pa *mdp)
   99 {
  100 
  101         mdp++;
  102         if (mdp->md_size == 0)
  103                 mdp = NULL;
  104         return (mdp);
  105 }
  106 
  107 /* XXX should be MI */
  108 static void
  109 mkdumpheader(struct kerneldumpheader *kdh, uint32_t archver, uint64_t dumplen,
  110     uint32_t blksz)
  111 {
  112 
  113         bzero(kdh, sizeof(*kdh));
  114         strncpy(kdh->magic, KERNELDUMPMAGIC, sizeof(kdh->magic));
  115         strncpy(kdh->architecture, MACHINE_ARCH, sizeof(kdh->architecture));
  116         kdh->version = htod32(KERNELDUMPVERSION);
  117         kdh->architectureversion = htod32(archver);
  118         kdh->dumplength = htod64(dumplen);
  119         kdh->dumptime = htod64(time_second);
  120         kdh->blocksize = htod32(blksz);
  121         strncpy(kdh->hostname, hostname, sizeof(kdh->hostname));
  122         strncpy(kdh->versionstring, version, sizeof(kdh->versionstring));
  123         if (panicstr != NULL)
  124                 strncpy(kdh->panicstring, panicstr, sizeof(kdh->panicstring));
  125         kdh->parity = kerneldump_parity(kdh);
  126 }
  127 
  128 static int
  129 buf_write(struct dumperinfo *di, char *ptr, size_t sz)
  130 {
  131         size_t len;
  132         int error;
  133 
  134         while (sz) {
  135                 len = DEV_BSIZE - fragsz;
  136                 if (len > sz)
  137                         len = sz;
  138                 bcopy(ptr, buffer + fragsz, len);
  139                 fragsz += len;
  140                 ptr += len;
  141                 sz -= len;
  142                 if (fragsz == DEV_BSIZE) {
  143                         error = dump_write(di, buffer, 0, dumplo,
  144                             DEV_BSIZE);
  145                         if (error)
  146                                 return error;
  147                         dumplo += DEV_BSIZE;
  148                         fragsz = 0;
  149                 }
  150         }
  151 
  152         return (0);
  153 }
  154 
  155 static int
  156 buf_flush(struct dumperinfo *di)
  157 {
  158         int error;
  159 
  160         if (fragsz == 0)
  161                 return (0);
  162 
  163         error = dump_write(di, buffer, 0, dumplo, DEV_BSIZE);
  164         dumplo += DEV_BSIZE;
  165         fragsz = 0;
  166         return (error);
  167 }
  168 
  169 #define PG2MB(pgs) ((pgs + (1 << 8) - 1) >> 8)
  170 
  171 static int
  172 cb_dumpdata(struct md_pa *mdp, int seqnr, void *arg)
  173 {
  174         struct dumperinfo *di = (struct dumperinfo*)arg;
  175         vm_paddr_t a, pa;
  176         void *va;
  177         uint64_t pgs;
  178         size_t counter, sz, chunk;
  179         int i, c, error, twiddle;
  180 
  181         error = 0;      /* catch case in which chunk size is 0 */
  182         counter = 0;    /* Update twiddle every 16MB */
  183         twiddle = 0;
  184         va = 0;
  185         pgs = mdp->md_size / PAGE_SIZE;
  186         pa = mdp->md_start;
  187 
  188         printf("  chunk %d: %lldMB (%lld pages)", seqnr, PG2MB(pgs), pgs);
  189 
  190         while (pgs) {
  191                 chunk = pgs;
  192                 if (chunk > MAXDUMPPGS)
  193                         chunk = MAXDUMPPGS;
  194                 sz = chunk << PAGE_SHIFT;
  195                 counter += sz;
  196                 if (counter >> 24) {
  197                         printf(" %lld", PG2MB(pgs));
  198                         counter &= (1<<24) - 1;
  199                 }
  200                 for (i = 0; i < chunk; i++) {
  201                         a = pa + i * PAGE_SIZE;
  202                         va = pmap_kenter_temporary(trunc_page(a), i);
  203                 }
  204                 error = dump_write(di, va, 0, dumplo, sz);
  205                 if (error)
  206                         break;
  207                 dumplo += sz;
  208                 pgs -= chunk;
  209                 pa += sz;
  210 
  211                 /* Check for user abort. */
  212                 c = cncheckc();
  213                 if (c == 0x03)
  214                         return (ECANCELED);
  215                 if (c != -1)
  216                         printf(" (CTRL-C to abort) ");
  217         }
  218         printf(" ... %s\n", (error) ? "fail" : "ok");
  219         return (error);
  220 }
  221 
  222 static int
  223 cb_dumphdr(struct md_pa *mdp, int seqnr, void *arg)
  224 {
  225         struct dumperinfo *di = (struct dumperinfo*)arg;
  226         Elf_Phdr phdr;
  227         uint64_t size;
  228         int error;
  229 
  230         size = mdp->md_size;
  231         bzero(&phdr, sizeof(phdr));
  232         phdr.p_type = PT_LOAD;
  233         phdr.p_flags = PF_R;                    /* XXX */
  234         phdr.p_offset = fileofs;
  235         phdr.p_vaddr = mdp->md_start;
  236         phdr.p_paddr = mdp->md_start;
  237         phdr.p_filesz = size;
  238         phdr.p_memsz = size;
  239         phdr.p_align = PAGE_SIZE;
  240 
  241         error = buf_write(di, (char*)&phdr, sizeof(phdr));
  242         fileofs += phdr.p_filesz;
  243         return (error);
  244 }
  245 
  246 static int
  247 cb_size(struct md_pa *mdp, int seqnr, void *arg)
  248 {
  249         uint64_t *sz = (uint64_t*)arg;
  250 
  251         *sz += (uint64_t)mdp->md_size;
  252         return (0);
  253 }
  254 
  255 static int
  256 foreach_chunk(callback_t cb, void *arg)
  257 {
  258         struct md_pa *mdp;
  259         int error, seqnr;
  260 
  261         seqnr = 0;
  262         mdp = md_pa_first();
  263         while (mdp != NULL) {
  264                 error = (*cb)(mdp, seqnr++, arg);
  265                 if (error)
  266                         return (-error);
  267                 mdp = md_pa_next(mdp);
  268         }
  269         return (seqnr);
  270 }
  271 
  272 void
  273 dumpsys(struct dumperinfo *di)
  274 {
  275         Elf_Ehdr ehdr;
  276         uint64_t dumpsize;
  277         off_t hdrgap;
  278         size_t hdrsz;
  279         int error;
  280 
  281         if (do_minidump) {
  282                 minidumpsys(di);
  283                 return;
  284         }
  285         bzero(&ehdr, sizeof(ehdr));
  286         ehdr.e_ident[EI_MAG0] = ELFMAG0;
  287         ehdr.e_ident[EI_MAG1] = ELFMAG1;
  288         ehdr.e_ident[EI_MAG2] = ELFMAG2;
  289         ehdr.e_ident[EI_MAG3] = ELFMAG3;
  290         ehdr.e_ident[EI_CLASS] = ELF_CLASS;
  291 #if BYTE_ORDER == LITTLE_ENDIAN
  292         ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
  293 #else
  294         ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
  295 #endif
  296         ehdr.e_ident[EI_VERSION] = EV_CURRENT;
  297         ehdr.e_ident[EI_OSABI] = ELFOSABI_STANDALONE;   /* XXX big picture? */
  298         ehdr.e_type = ET_CORE;
  299         ehdr.e_machine = EM_386;
  300         ehdr.e_phoff = sizeof(ehdr);
  301         ehdr.e_flags = 0;
  302         ehdr.e_ehsize = sizeof(ehdr);
  303         ehdr.e_phentsize = sizeof(Elf_Phdr);
  304         ehdr.e_shentsize = sizeof(Elf_Shdr);
  305 
  306         md_pa_init();
  307 
  308         /* Calculate dump size. */
  309         dumpsize = 0L;
  310         ehdr.e_phnum = foreach_chunk(cb_size, &dumpsize);
  311         hdrsz = ehdr.e_phoff + ehdr.e_phnum * ehdr.e_phentsize;
  312         fileofs = MD_ALIGN(hdrsz);
  313         dumpsize += fileofs;
  314         hdrgap = fileofs - DEV_ALIGN(hdrsz);
  315 
  316         /* Determine dump offset on device. */
  317         if (di->mediasize < SIZEOF_METADATA + dumpsize + sizeof(kdh) * 2) {
  318                 error = ENOSPC;
  319                 goto fail;
  320         }
  321         dumplo = di->mediaoffset + di->mediasize - dumpsize;
  322         dumplo -= sizeof(kdh) * 2;
  323 
  324         mkdumpheader(&kdh, KERNELDUMP_I386_VERSION, dumpsize, di->blocksize);
  325 
  326         printf("Dumping %llu MB (%d chunks)\n", (long long)dumpsize >> 20,
  327             ehdr.e_phnum);
  328 
  329         /* Dump leader */
  330         error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
  331         if (error)
  332                 goto fail;
  333         dumplo += sizeof(kdh);
  334 
  335         /* Dump ELF header */
  336         error = buf_write(di, (char*)&ehdr, sizeof(ehdr));
  337         if (error)
  338                 goto fail;
  339 
  340         /* Dump program headers */
  341         error = foreach_chunk(cb_dumphdr, di);
  342         if (error < 0)
  343                 goto fail;
  344         buf_flush(di);
  345 
  346         /*
  347          * All headers are written using blocked I/O, so we know the
  348          * current offset is (still) block aligned. Skip the alignement
  349          * in the file to have the segment contents aligned at page
  350          * boundary. We cannot use MD_ALIGN on dumplo, because we don't
  351          * care and may very well be unaligned within the dump device.
  352          */
  353         dumplo += hdrgap;
  354 
  355         /* Dump memory chunks (updates dumplo) */
  356         error = foreach_chunk(cb_dumpdata, di);
  357         if (error < 0)
  358                 goto fail;
  359 
  360         /* Dump trailer */
  361         error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
  362         if (error)
  363                 goto fail;
  364 
  365         /* Signal completion, signoff and exit stage left. */
  366         dump_write(di, NULL, 0, 0, 0);
  367         printf("\nDump complete\n");
  368         return;
  369 
  370  fail:
  371         if (error < 0)
  372                 error = -error;
  373 
  374         if (error == ECANCELED)
  375                 printf("\nDump aborted\n");
  376         else if (error == ENOSPC)
  377                 printf("\nDump failed. Partition too small.\n");
  378         else
  379                 printf("\n** DUMP FAILED (ERROR %d) **\n", error);
  380 }

Cache object: 5a22113ce9445af9d4e90890e145c89d


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