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 <stdlib.h>
  52 #include <unistd.h>
  53 #include <nlist.h>
  54 #include <kvm.h>
  55
  56 #include <vm/vm.h>
  57 #include <vm/vm_param.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 struct vmstate {
  69         pd_entry_t      *PTD;
  70 };
  71
  72 void
  73 _kvm_freevtop(kvm_t *kd)
  74 {
  75         if (kd->vmst != 0) {
  76                 if (kd->vmst->PTD) {
  77                         free(kd->vmst->PTD);
  78                 }
  79                 free(kd->vmst);
  80         }
  81 }
  82
  83 int
  84 _kvm_initvtop(kvm_t *kd)
  85 {
  86         struct vmstate *vm;
  87         struct nlist nlist[2];
  88         u_long pa;
  89         u_long kernbase;
  90         pd_entry_t      *PTD;
  91
  92         vm = (struct vmstate *)_kvm_malloc(kd, sizeof(*vm));
  93         if (vm == 0) {
  94                 _kvm_err(kd, kd->program, "cannot allocate vm");
  95                 return (-1);
  96         }
  97         kd->vmst = vm;
  98         vm->PTD = 0;
  99
 100         nlist[0].n_name = "_kernbase";
 101         nlist[1].n_name = 0;
 102
 103         if (kvm_nlist(kd, nlist) != 0)
 104                 kernbase = KERNBASE;    /* for old kernels */
 105         else
 106                 kernbase = nlist[0].n_value;
 107
 108         nlist[0].n_name = "_IdlePTD";
 109         nlist[1].n_name = 0;
 110
 111         if (kvm_nlist(kd, nlist) != 0) {
 112                 _kvm_err(kd, kd->program, "bad namelist");
 113                 return (-1);
 114         }
 115         if (kvm_read(kd, (nlist[0].n_value - kernbase), &pa, sizeof(pa)) !=
 116             sizeof(pa)) {
 117                 _kvm_err(kd, kd->program, "cannot read IdlePTD");
 118                 return (-1);
 119         }
 120         PTD = _kvm_malloc(kd, PAGE_SIZE);
 121         if (kvm_read(kd, pa, PTD, PAGE_SIZE) != PAGE_SIZE) {
 122                 _kvm_err(kd, kd->program, "cannot read PTD");
 123                 return (-1);
 124         }
 125         vm->PTD = PTD;
 126         return (0);
 127 }
 128
 129 static int
 130 _kvm_vatop(kvm_t *kd, u_long va, u_long *pa)
 131 {
 132         struct vmstate *vm;
 133         u_long offset;
 134         u_long pte_pa;
 135         pd_entry_t pde;
 136         pt_entry_t pte;
 137         u_long pdeindex;
 138         u_long pteindex;
 139
 140         if (kvm_ishost(kd)) {
 141                 _kvm_err(kd, 0, "vatop called in live kernel!");
 142                 return((off_t)0);
 143         }
 144
 145         vm = kd->vmst;
 146         offset = va & (PAGE_SIZE - 1);
 147
 148         /*
 149          * If we are initializing (kernel page table descriptor pointer
 150          * not yet set) then return pa == va to avoid infinite recursion.
 151          */
 152         if (vm->PTD == 0) {
 153                 *pa = va;
 154                 return (PAGE_SIZE - offset);
 155         }
 156
 157         pdeindex = va >> PDRSHIFT;
 158         pde = vm->PTD[pdeindex];
 159         if (((u_long)pde & PG_V) == 0)
 160                 goto invalid;
 161
 162         if ((u_long)pde & PG_PS) {
 163               /*
 164                * No second-level page table; ptd describes one 4MB page.
 165                * (We assume that the kernel wouldn't set PG_PS without enabling
 166                * it cr0, and that the kernel doesn't support 36-bit physical
 167                * addresses).
 168                */
 169 #define PAGE4M_MASK     (NBPDR - 1)
 170 #define PG_FRAME4M      (~PAGE4M_MASK)
 171                 *pa = ((u_long)pde & PG_FRAME4M) + (va & PAGE4M_MASK);
 172                 return (NBPDR - (va & PAGE4M_MASK));
 173         }
 174
 175         pteindex = (va >> PAGE_SHIFT) & (NPTEPG-1);
 176         pte_pa = ((u_long)pde & PG_FRAME) + (pteindex * sizeof(pt_entry_t));
 177
 178         /* XXX This has to be a physical address read, kvm_read is virtual */
 179         if (lseek(kd->pmfd, pte_pa, 0) == -1) {
 180                 _kvm_syserr(kd, kd->program, "_kvm_vatop: lseek");
 181                 goto invalid;
 182         }
 183         if (read(kd->pmfd, &pte, sizeof pte) != sizeof pte) {
 184                 _kvm_syserr(kd, kd->program, "_kvm_vatop: read");
 185                 goto invalid;
 186         }
 187         if (((u_long)pte & PG_V) == 0)
 188                 goto invalid;
 189
 190         *pa = ((u_long)pte & PG_FRAME) + offset;
 191         return (PAGE_SIZE - offset);
 192
 193 invalid:
 194         _kvm_err(kd, 0, "invalid address (%x)", va);
 195         return (0);
 196 }
 197
 198 int
 199 _kvm_kvatop(kvm_t *kd, u_long va, u_long *pa)
 200 {
 201         return (_kvm_vatop(kd, va, pa));
 202 }