lib/libkvm/kvm_i386.c

   1 /*-
   2  * Copyright (c) 1989, 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software developed by the Computer Systems
   6  * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
   7  * BG 91-66 and contributed to Berkeley.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by the University of
  20  *      California, Berkeley and its contributors.
  21  * 4. Neither the name of the University nor the names of its contributors
  22  *    may be used to endorse or promote products derived from this software
  23  *    without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35  * SUCH DAMAGE.
  36  *
  37  * @(#)kvm_hp300.c      8.1 (Berkeley) 6/4/93
  38  * $FreeBSD: src/lib/libkvm/kvm_i386.c,v 1.11.2.1 2001/09/21 04:01:51 peter Exp $
  39  * $DragonFly: src/lib/libkvm/kvm_i386.c,v 1.3 2007/04/29 01:36:04 dillon Exp $
  40  */
  41
  42 /*
  43  * i386 machine dependent routines for kvm.  Hopefully, the forthcoming
  44  * vm code will one day obsolete this module.
  45  */
  46
  47 #include <sys/user.h>   /* MUST BE FIRST */
  48 #include <sys/param.h>
  49 #include <sys/proc.h>
  50 #include <sys/stat.h>
  51 #include <sys/mman.h>
  52 #include <sys/elf_common.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <unistd.h>
  56 #include <nlist.h>
  57 #include <kvm.h>
  58
  59 #include <vm/vm.h>
  60 #include <vm/vm_param.h>
  61
  62 #include <machine/elf.h>
  63
  64 #include <limits.h>
  65
  66 #include "kvm_private.h"
  67
  68 #ifndef btop
  69 #define btop(x)         (i386_btop(x))
  70 #define ptob(x)         (i386_ptob(x))
  71 #endif
  72
  73 /* minidump must be the first item! */
  74 struct vmstate {
  75         int             minidump;       /* 1 = minidump mode */
  76         void            *mmapbase;
  77         size_t          mmapsize;
  78         void            *PTD;
  79 };
  80
  81 /*
  82  * Map the ELF headers into the process' address space. We do this in two
  83  * steps: first the ELF header itself and using that information the whole
  84  * set of headers. (Taken from kvm_ia64.c)
  85  */
  86 static int
  87 _kvm_maphdrs(kvm_t *kd, size_t sz)
  88 {
  89         struct vmstate *vm = kd->vmst;
  90
  91         if (kd->vmst->minidump) {
  92                 _kvm_minidump_freevtop(kd);
  93                 return (0);
  94         }
  95
  96         /* munmap() previous mmap(). */
  97         if (vm->mmapbase != NULL) {
  98                 munmap(vm->mmapbase, vm->mmapsize);
  99                 vm->mmapbase = NULL;
 100         }
 101
 102         vm->mmapsize = sz;
 103         vm->mmapbase = mmap(NULL, sz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
 104         if (vm->mmapbase == MAP_FAILED) {
 105                 _kvm_err(kd, kd->program, "cannot mmap corefile");
 106                 return (-1);
 107         }
 108         return (0);
 109 }
 110
 111 /*
 112  * Translate a physical memory address to a file-offset in the crash-dump.
 113  * (Taken from kvm_ia64.c)
 114  */
 115 static size_t
 116 _kvm_pa2off(kvm_t *kd, uint64_t pa, off_t *ofs)
 117 {
 118         Elf_Ehdr *e = kd->vmst->mmapbase;
 119         Elf_Phdr *p;
 120         int n;
 121
 122         if (kd->rawdump) {
 123                 *ofs = pa;
 124                 return (PAGE_SIZE - ((size_t)pa & PAGE_MASK));
 125         }
 126
 127         p = (Elf_Phdr*)((char*)e + e->e_phoff);
 128         n = e->e_phnum;
 129
 130         while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
 131                 p++, n--;
 132         if (n == 0)
 133                 return (0);
 134         *ofs = (pa - p->p_paddr) + p->p_offset;
 135         return (PAGE_SIZE - ((size_t)pa & PAGE_MASK));
 136 }
 137
 138 void
 139 _kvm_freevtop(kvm_t *kd)
 140 {
 141         struct vmstate  *vm = kd->vmst;
 142
 143         if (kd->vmst->minidump) {
 144                 _kvm_minidump_freevtop(kd);
 145                 return;
 146         }
 147
 148         if (vm->mmapbase != NULL)
 149                 munmap(vm->mmapbase, vm->mmapsize);
 150         if (vm->PTD)
 151                 free(vm->PTD);
 152         free(vm);
 153         kd->vmst = NULL;
 154 }
 155
 156 int
 157 _kvm_initvtop(kvm_t *kd)
 158 {
 159         struct nlist nlist[2];
 160         u_long pa;
 161         u_long kernbase;
 162         char            *PTD;
 163         Elf_Ehdr        *ehdr;
 164         size_t          hdrsz;
 165         char            minihdr[8];
 166
 167         if (pread(kd->pmfd, &minihdr, 8, 0) == 8)
 168                 if (memcmp(&minihdr, "minidump", 8) == 0)
 169                         return (_kvm_minidump_initvtop(kd));
 170
 171         kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
 172         if (kd->vmst == 0) {
 173                 _kvm_err(kd, kd->program, "cannot allocate vm");
 174                 return (-1);
 175         }
 176         kd->vmst->PTD = 0;
 177
 178         if (_kvm_maphdrs(kd, sizeof(Elf_Ehdr)) == -1)
 179                 return (-1);
 180         /*
 181          * Check if this is indeed an ELF header. If not, assume old style dump or
 182          * memory layout.
 183          */
 184         ehdr = kd->vmst->mmapbase;
 185         if (!IS_ELF(*ehdr)) {
 186                 kd->rawdump = 1;
 187                 munmap(kd->vmst->mmapbase, kd->vmst->mmapsize);
 188                 kd->vmst->mmapbase = NULL;
 189         } else {
 190                 hdrsz = ehdr->e_phoff + ehdr->e_phentsize * ehdr->e_phnum;
 191                 if (_kvm_maphdrs(kd, hdrsz) == -1)
 192                         return (-1);
 193         }
 194
 195         nlist[0].n_name = "_kernbase";
 196         nlist[1].n_name = 0;
 197
 198         if (kvm_nlist(kd, nlist) != 0)
 199                 kernbase = KERNBASE;    /* for old kernels */
 200         else
 201                 kernbase = nlist[0].n_value;
 202
 203         nlist[0].n_name = "_IdlePTD";
 204         nlist[1].n_name = 0;
 205
 206         if (kvm_nlist(kd, nlist) != 0) {
 207                 _kvm_err(kd, kd->program, "bad namelist");
 208                 return (-1);
 209         }
 210         if (kvm_read(kd, (nlist[0].n_value - kernbase), &pa, sizeof(pa)) !=
 211             sizeof(pa)) {
 212                 _kvm_err(kd, kd->program, "cannot read IdlePTD");
 213                 return (-1);
 214         }
 215         PTD = _kvm_malloc(kd, PAGE_SIZE);
 216         if (kvm_read(kd, pa, PTD, PAGE_SIZE) != PAGE_SIZE) {
 217                 _kvm_err(kd, kd->program, "cannot read PTD");
 218                 return (-1);
 219         }
 220         kd->vmst->PTD = PTD;
 221         return (0);
 222 }
 223
 224 static int
 225 _kvm_vatop(kvm_t *kd, u_long va, off_t *pa)
 226 {
 227         struct vmstate *vm;
 228         u_long offset;
 229         u_long pte_pa;
 230         u_long pde_pa;
 231         pd_entry_t pde;
 232         pt_entry_t pte;
 233         u_long pdeindex;
 234         u_long pteindex;
 235         size_t  s;
 236         u_long  a;
 237         off_t   ofs;
 238         uint32_t *PTD;
 239
 240
 241         vm = kd->vmst;
 242         PTD = (uint32_t *)vm->PTD;
 243         offset = va & (PAGE_SIZE - 1);
 244
 245         /*
 246          * If we are initializing (kernel page table descriptor pointer
 247          * not yet set) then return pa == va to avoid infinite recursion.
 248          */
 249         if (PTD == 0) {
 250                 s = _kvm_pa2off(kd, va, pa);
 251                 if (s == 0) {
 252                         _kvm_err(kd, kd->program,
 253                             "_kvm_vatop: bootstrap data not in dump");
 254                         goto invalid;
 255                 } else {
 256                         return (PAGE_SIZE - offset);
 257                 }
 258         }
 259
 260         pdeindex = va >> PDRSHIFT;
 261         pde = PTD[pdeindex];
 262
 263         if (((u_long)pde & PG_V) == 0) {
 264                 _kvm_err(kd, kd->program, "_kvm_vatop: pde not valid");
 265                 goto invalid;
 266         }
 267
 268         if ((u_long)pde & PG_PS) {
 269               /*
 270                * No second-level page table; ptd describes one 4MB page.
 271                * (We assume that the kernel wouldn't set PG_PS without enabling
 272                * it cr0, and that the kernel doesn't support 36-bit physical
 273                * addresses).
 274                */
 275 #define PAGE4M_MASK     (NBPDR - 1)
 276 #define PG_FRAME4M      (~PAGE4M_MASK)
 277 #if 0
 278                 *pa = ((u_long)pde & PG_FRAME4M) + (va & PAGE4M_MASK);
 279 #endif
 280                 pde_pa = ((u_long)pde & PG_FRAME4M) + (va & PAGE4M_MASK);
 281                 s = _kvm_pa2off(kd, pde_pa, &ofs);
 282                 if (s <= sizeof pde) {
 283                         _kvm_syserr(kd, kd->program,
 284                             "_kvm_vatop: pde_pa not found");
 285                         goto invalid;
 286                 }
 287                 *pa = ofs;
 288
 289                 return (NBPDR - (va & PAGE4M_MASK));
 290         }
 291
 292         pteindex = (va >> PAGE_SHIFT) & (NPTEPG-1);
 293         pte_pa = ((u_long)pde & PG_FRAME) + (pteindex * sizeof(pde));
 294
 295         s = _kvm_pa2off(kd, pte_pa, &ofs);
 296         if (s <= sizeof pte) {
 297                 _kvm_err(kd, kd->program, "_kvm_vatop: pdpe_pa not found");
 298                 goto invalid;
 299         }
 300
 301         /* XXX This has to be a physical address read, kvm_read is virtual */
 302         if (lseek(kd->pmfd, ofs, 0) == -1) {
 303                 _kvm_syserr(kd, kd->program, "_kvm_vatop: lseek");
 304                 goto invalid;
 305         }
 306         if (read(kd->pmfd, &pte, sizeof pte) != sizeof pte) {
 307                 _kvm_syserr(kd, kd->program, "_kvm_vatop: read");
 308                 goto invalid;
 309         }
 310         if (((u_long)pte & PG_V) == 0) {
 311                 _kvm_err(kd, kd->program, "_kvm_kvatop: pte not valid");
 312                 goto invalid;
 313         }
 314
 315         a = ((u_long)pte & PG_FRAME) + offset;
 316         s =_kvm_pa2off(kd, a, pa);
 317         if (s == 0) {
 318                 _kvm_err(kd, kd->program, "_kvm_vatop: address not in dump");
 319                 goto invalid;
 320         } else
 321                 return (PAGE_SIZE - offset);
 322
 323 invalid:
 324         _kvm_err(kd, 0, "invalid address (0x%lx)", va);
 325         return (0);
 326 }
 327
 328 int
 329 _kvm_kvatop(kvm_t *kd, u_long va, off_t *pa)
 330 {
 331         if (kd->vmst->minidump)
 332                 return (_kvm_minidump_kvatop(kd, va, pa));
 333
 334         if (kvm_ishost(kd)) {
 335                 _kvm_err(kd, 0, "vatop called in live kernel!");
 336                 return (0);
 337         }
 338
 339         return (_kvm_vatop(kd, va, pa));
 340 }