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. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * @(#)kvm_hp300.c      8.1 (Berkeley) 6/4/93
  34  * $FreeBSD: src/lib/libkvm/kvm_i386.c,v 1.11.2.1 2001/09/21 04:01:51 peter Exp $
  35  */
  36
  37 /*
  38  * i386 machine dependent routines for kvm.  Hopefully, the forthcoming
  39  * vm code will one day obsolete this module.
  40  */
  41
  42 #include <sys/user.h>   /* MUST BE FIRST */
  43 #include <sys/param.h>
  44 #include <sys/proc.h>
  45 #include <sys/stat.h>
  46 #include <sys/mman.h>
  47 #include <sys/elf_common.h>
  48 #include <stdlib.h>
  49 #include <string.h>
  50 #include <unistd.h>
  51 #include <nlist.h>
  52 #include <kvm.h>
  53
  54 #include <vm/vm.h>
  55 #include <vm/vm_param.h>
  56
  57 #include <machine/elf.h>
  58
  59 #include <limits.h>
  60
  61 #include "kvm_private.h"
  62
  63 #ifndef btop
  64 #define btop(x)         (i386_btop(x))
  65 #define ptob(x)         (i386_ptob(x))
  66 #endif
  67
  68 /* minidump must be the first item! */
  69 struct vmstate {
  70         int             minidump;       /* 1 = minidump mode */
  71         void            *mmapbase;
  72         size_t          mmapsize;
  73         void            *PTD;
  74 };
  75
  76 /*
  77  * Map the ELF headers into the process' address space. We do this in two
  78  * steps: first the ELF header itself and using that information the whole
  79  * set of headers. (Taken from kvm_ia64.c)
  80  */
  81 static int
  82 _kvm_maphdrs(kvm_t *kd, size_t sz)
  83 {
  84         struct vmstate *vm = kd->vmst;
  85
  86         if (kd->vmst->minidump) {
  87                 _kvm_minidump_freevtop(kd);
  88                 return (0);
  89         }
  90
  91         /* munmap() previous mmap(). */
  92         if (vm->mmapbase != NULL) {
  93                 munmap(vm->mmapbase, vm->mmapsize);
  94                 vm->mmapbase = NULL;
  95         }
  96
  97         vm->mmapsize = sz;
  98         vm->mmapbase = mmap(NULL, sz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
  99         if (vm->mmapbase == MAP_FAILED) {
 100                 _kvm_err(kd, kd->program, "cannot mmap corefile");
 101                 return (-1);
 102         }
 103         return (0);
 104 }
 105
 106 /*
 107  * Translate a physical memory address to a file-offset in the crash-dump.
 108  * (Taken from kvm_ia64.c)
 109  */
 110 static size_t
 111 _kvm_pa2off(kvm_t *kd, uint64_t pa, off_t *ofs)
 112 {
 113         Elf_Ehdr *e = kd->vmst->mmapbase;
 114         Elf_Phdr *p;
 115         int n;
 116
 117         if (kd->rawdump) {
 118                 *ofs = pa;
 119                 return (PAGE_SIZE - ((size_t)pa & PAGE_MASK));
 120         }
 121
 122         p = (Elf_Phdr*)((char*)e + e->e_phoff);
 123         n = e->e_phnum;
 124
 125         while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
 126                 p++, n--;
 127         if (n == 0)
 128                 return (0);
 129         *ofs = (pa - p->p_paddr) + p->p_offset;
 130         return (PAGE_SIZE - ((size_t)pa & PAGE_MASK));
 131 }
 132
 133 void
 134 _kvm_freevtop(kvm_t *kd)
 135 {
 136         struct vmstate  *vm = kd->vmst;
 137
 138         if (kd->vmst->minidump) {
 139                 _kvm_minidump_freevtop(kd);
 140                 return;
 141         }
 142
 143         if (vm->mmapbase != NULL)
 144                 munmap(vm->mmapbase, vm->mmapsize);
 145         if (vm->PTD)
 146                 free(vm->PTD);
 147         free(vm);
 148         kd->vmst = NULL;
 149 }
 150
 151 int
 152 _kvm_initvtop(kvm_t *kd)
 153 {
 154         struct nlist nlist[2];
 155         u_long pa;
 156         u_long kernbase;
 157         char            *PTD;
 158         Elf_Ehdr        *ehdr;
 159         size_t          hdrsz;
 160         char            minihdr[8];
 161         struct pcb      dumppcb;
 162
 163         if (pread(kd->pmfd, &minihdr, 8, 0) == 8)
 164                 if (memcmp(&minihdr, "minidump", 8) == 0)
 165                         return (_kvm_minidump_initvtop(kd));
 166
 167         kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
 168         if (kd->vmst == 0) {
 169                 _kvm_err(kd, kd->program, "cannot allocate vm");
 170                 return (-1);
 171         }
 172         kd->vmst->PTD = 0;
 173
 174         if (_kvm_maphdrs(kd, sizeof(Elf_Ehdr)) == -1)
 175                 return (-1);
 176         /*
 177          * Check if this is indeed an ELF header. If not, assume old style dump or
 178          * memory layout.
 179          */
 180         ehdr = kd->vmst->mmapbase;
 181         if (!IS_ELF(*ehdr)) {
 182                 kd->rawdump = 1;
 183                 munmap(kd->vmst->mmapbase, kd->vmst->mmapsize);
 184                 kd->vmst->mmapbase = NULL;
 185         } else {
 186                 hdrsz = ehdr->e_phoff + ehdr->e_phentsize * ehdr->e_phnum;
 187                 if (_kvm_maphdrs(kd, hdrsz) == -1)
 188                         return (-1);
 189         }
 190
 191         nlist[0].n_name = "_kernbase";
 192         nlist[1].n_name = 0;
 193
 194         if (kvm_nlist(kd, nlist) != 0)
 195                 kernbase = KERNBASE;    /* for old kernels */
 196         else
 197                 kernbase = nlist[0].n_value;
 198
 199         nlist[0].n_name = "_dumppcb";
 200         nlist[1].n_name = 0;
 201
 202         if (kvm_nlist(kd, nlist) != 0) {
 203                 _kvm_err(kd, kd->program, "bad namelist");
 204                 return (-1);
 205         }
 206
 207         if (kvm_read(kd, (nlist[0].n_value - kernbase), &dumppcb,
 208                      sizeof(dumppcb)) != sizeof(dumppcb)) {
 209                 _kvm_err(kd, kd->program, "cannot read dumppcb");
 210                 return (-1);
 211         }
 212         pa = dumppcb.pcb_cr3 & PG_FRAME;
 213
 214         PTD = _kvm_malloc(kd, PAGE_SIZE);
 215         if (kvm_read(kd, pa, PTD, PAGE_SIZE) != PAGE_SIZE) {
 216                 _kvm_err(kd, kd->program, "cannot read PTD");
 217                 return (-1);
 218         }
 219         kd->vmst->PTD = PTD;
 220         return (0);
 221 }
 222
 223 static int
 224 _kvm_vatop(kvm_t *kd, u_long va, off_t *pa)
 225 {
 226         struct vmstate *vm;
 227         u_long offset;
 228         u_long pte_pa;
 229         u_long pde_pa;
 230         pd_entry_t pde;
 231         pt_entry_t pte;
 232         u_long pdeindex;
 233         u_long pteindex;
 234         size_t  s;
 235         u_long  a;
 236         off_t   ofs;
 237         uint32_t *PTD;
 238
 239
 240         vm = kd->vmst;
 241         PTD = (uint32_t *)vm->PTD;
 242         offset = va & (PAGE_SIZE - 1);
 243
 244         /*
 245          * If we are initializing (kernel page table descriptor pointer
 246          * not yet set) then return pa == va to avoid infinite recursion.
 247          */
 248         if (PTD == NULL) {
 249                 s = _kvm_pa2off(kd, va, pa);
 250                 if (s == 0) {
 251                         _kvm_err(kd, kd->program,
 252                             "_kvm_vatop: bootstrap data not in dump");
 253                         goto invalid;
 254                 } else {
 255                         return (PAGE_SIZE - offset);
 256                 }
 257         }
 258
 259         pdeindex = va >> PDRSHIFT;
 260         pde = PTD[pdeindex];
 261
 262         if (((u_long)pde & PG_V) == 0) {
 263                 _kvm_err(kd, kd->program, "_kvm_vatop: pde not valid");
 264                 goto invalid;
 265         }
 266
 267         if ((u_long)pde & PG_PS) {
 268               /*
 269                * No second-level page table; ptd describes one 4MB page.
 270                * (We assume that the kernel wouldn't set PG_PS without enabling
 271                * it cr0, and that the kernel doesn't support 36-bit physical
 272                * addresses).
 273                */
 274 #define PAGE4M_MASK     (NBPDR - 1)
 275 #define PG_FRAME4M      (~PAGE4M_MASK)
 276 #if 0
 277                 *pa = ((u_long)pde & PG_FRAME4M) + (va & PAGE4M_MASK);
 278 #endif
 279                 pde_pa = ((u_long)pde & PG_FRAME4M) + (va & PAGE4M_MASK);
 280                 s = _kvm_pa2off(kd, pde_pa, &ofs);
 281                 if (s < sizeof pde) {
 282                         _kvm_syserr(kd, kd->program,
 283                             "_kvm_vatop: pde_pa not found");
 284                         goto invalid;
 285                 }
 286                 *pa = ofs;
 287
 288                 return (NBPDR - (va & PAGE4M_MASK));
 289         }
 290
 291         pteindex = (va >> PAGE_SHIFT) & (NPTEPG-1);
 292         pte_pa = ((u_long)pde & PG_FRAME) + (pteindex * sizeof(pde));
 293
 294         s = _kvm_pa2off(kd, pte_pa, &ofs);
 295         if (s < sizeof pte) {
 296                 _kvm_err(kd, kd->program, "_kvm_vatop: pdpe_pa not found");
 297                 goto invalid;
 298         }
 299
 300         /* XXX This has to be a physical address read, kvm_read is virtual */
 301         if (lseek(kd->pmfd, ofs, 0) == -1) {
 302                 _kvm_syserr(kd, kd->program, "_kvm_vatop: lseek");
 303                 goto invalid;
 304         }
 305         if (read(kd->pmfd, &pte, sizeof pte) != sizeof pte) {
 306                 _kvm_syserr(kd, kd->program, "_kvm_vatop: read");
 307                 goto invalid;
 308         }
 309         if (((u_long)pte & PG_V) == 0) {
 310                 _kvm_err(kd, kd->program, "_kvm_kvatop: pte not valid");
 311                 goto invalid;
 312         }
 313
 314         a = ((u_long)pte & PG_FRAME) + offset;
 315         s =_kvm_pa2off(kd, a, pa);
 316         if (s == 0) {
 317                 _kvm_err(kd, kd->program, "_kvm_vatop: address not in dump");
 318                 goto invalid;
 319         } else
 320                 return (PAGE_SIZE - offset);
 321
 322 invalid:
 323         _kvm_err(kd, 0, "invalid address (0x%lx)", va);
 324         return (0);
 325 }
 326
 327 int
 328 _kvm_kvatop(kvm_t *kd, u_long va, off_t *pa)
 329 {
 330         if (kd->vmst->minidump)
 331                 return (_kvm_minidump_kvatop(kd, va, pa));
 332
 333         if (kvm_ishost(kd)) {
 334                 _kvm_err(kd, 0, "vatop called in live kernel!");
 335                 return (0);
 336         }
 337
 338         return (_kvm_vatop(kd, va, pa));
 339 }