1 /* $OpenBSD: kvm_i386.c,v 1.28 2021/12/01 16:53:28 deraadt Exp $ */
2 /* $NetBSD: kvm_i386.c,v 1.9 1996/03/18 22:33:38 thorpej Exp $ */
3
4 /*-
5 * Copyright (c) 1989, 1992, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software developed by the Computer Systems
9 * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
10 * BG 91-66 and contributed to Berkeley.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
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/types.h>
43 #include <sys/signal.h>
44 #include <sys/proc.h>
45 #include <sys/stat.h>
46 #include <stdlib.h>
47 #include <unistd.h>
48 #include <nlist.h>
49 #include <kvm.h>
50
51 #include <uvm/uvm_extern.h>
52 #include <machine/param.h>
53 #include <machine/vmparam.h>
54 #include <machine/pmap.h>
55
56 #include <limits.h>
57 #include <db.h>
58
59 #include "kvm_private.h"
60
61 #include <machine/pte.h>
62
63 /*
64 * We access both normal and PAE entries in 32bit chunks.
65 * Use a local name to avoid conflicting with the kernel's maybe-public,
66 * maybe-not p[td]_entry_t typedefs.
67 */
68 typedef u_long ptd_entry_t;
69
70 /*
71 * These must match the values in pmap.c/pmapae.c
72 * First the non-PAE versions
73 */
74 #define PD_MASK 0xffc00000 /* page directory address bits */
75 #define PT_MASK 0x003ff000 /* page table address bits */
76
77 /*
78 * PAE versions
79 *
80 * paddr_t is still 32bits, so the top 32bits of PDEs and PTEs only
81 * matters for the NX bit...which libkvm doesn't care about
82 */
83 #define PAE_PDSHIFT 21
84 #define PAE_PD_MASK 0xffe00000 /* page directory address bits */
85 #define PAE_PT_MASK 0x001ff000 /* page table address bits */
86
87 #define PG_FRAME 0xfffff000
88
89 static int cpu_pae;
90
91 struct vmstate {
92 ptd_entry_t *PTD;
93 ptd_entry_t PD_mask;
94 ptd_entry_t PT_mask;
95 int PD_shift;
96 int PG_shift;
97 };
98
99 #define pdei(vm,VA) (((VA) & (vm)->PD_mask) >> (vm)->PD_shift)
100 #define ptei(vm,VA) (((VA) & (vm)->PT_mask) >> PAGE_SHIFT)
101
102 void
_kvm_freevtop(kvm_t * kd)103 _kvm_freevtop(kvm_t *kd)
104 {
105 if (kd->vmst != NULL) {
106 free(kd->vmst->PTD);
107
108 free(kd->vmst);
109 kd->vmst = NULL;
110 }
111 }
112
113 int
_kvm_initvtop(kvm_t * kd)114 _kvm_initvtop(kvm_t *kd)
115 {
116 struct nlist nl[4];
117 struct vmstate *vm;
118 u_long pa, PTDsize;
119
120 vm = _kvm_malloc(kd, sizeof(*vm));
121 if (vm == NULL)
122 return (-1);
123 kd->vmst = vm;
124
125 vm->PTD = NULL;
126
127 nl[0].n_name = "_PTDpaddr";
128 nl[1].n_name = "_PTDsize";
129 nl[2].n_name = "_cpu_pae";
130 nl[3].n_name = NULL;
131
132 if (kvm_nlist(kd, nl) != 0) {
133 _kvm_err(kd, kd->program, "bad namelist");
134 return (-1);
135 }
136
137 if (_kvm_pread(kd, kd->pmfd, &cpu_pae, sizeof cpu_pae,
138 _kvm_pa2off(kd, nl[2].n_value - KERNBASE)) != sizeof cpu_pae)
139 goto invalid;
140
141 if (_kvm_pread(kd, kd->pmfd, &PTDsize, sizeof PTDsize,
142 _kvm_pa2off(kd, nl[1].n_value - KERNBASE)) != sizeof PTDsize)
143 goto invalid;
144
145 if (_kvm_pread(kd, kd->pmfd, &pa, sizeof pa,
146 _kvm_pa2off(kd, nl[0].n_value - KERNBASE)) != sizeof pa)
147 goto invalid;
148
149 vm->PTD = _kvm_malloc(kd, PTDsize);
150
151 if (_kvm_pread(kd, kd->pmfd, vm->PTD, PTDsize,
152 _kvm_pa2off(kd, pa)) != PTDsize)
153 goto invalid;
154
155 if (cpu_pae) {
156 vm->PD_mask = PAE_PD_MASK;
157 vm->PT_mask = PAE_PT_MASK;
158 /* -1 here because entries are twice as large */
159 vm->PD_shift = PAE_PDSHIFT - 1;
160 vm->PG_shift = PAGE_SHIFT - 1;
161 } else {
162 vm->PD_mask = PD_MASK;
163 vm->PT_mask = PT_MASK;
164 vm->PD_shift = PDSHIFT;
165 vm->PG_shift = PAGE_SHIFT;
166 }
167
168 return (0);
169
170 invalid:
171 free(vm->PTD);
172 vm->PTD = NULL;
173 return (-1);
174 }
175
176 /*
177 * Translate a kernel virtual address to a physical address.
178 */
179 int
_kvm_kvatop(kvm_t * kd,u_long va,paddr_t * pa)180 _kvm_kvatop(kvm_t *kd, u_long va, paddr_t *pa)
181 {
182 u_long offset, pte_pa;
183 struct vmstate *vm;
184 ptd_entry_t pte;
185
186 if (!kd->vmst) {
187 _kvm_err(kd, 0, "vatop called before initvtop");
188 return (0);
189 }
190
191 if (ISALIVE(kd)) {
192 _kvm_err(kd, 0, "vatop called in live kernel!");
193 return (0);
194 }
195
196 vm = kd->vmst;
197 offset = va & (kd->nbpg - 1);
198
199 /*
200 * If we are initializing (kernel page table descriptor pointer
201 * not yet set) * then return pa == va to avoid infinite recursion.
202 */
203 if (vm->PTD == NULL) {
204 *pa = va;
205 return (kd->nbpg - (int)offset);
206 }
207 if ((vm->PTD[pdei(vm,va)] & PG_V) == 0)
208 goto invalid;
209
210 pte_pa = (vm->PTD[pdei(vm,va)] & PG_FRAME) +
211 (ptei(vm,va) * sizeof(ptd_entry_t));
212
213 /* XXX READ PHYSICAL XXX */
214 if (_kvm_pread(kd, kd->pmfd, &pte, sizeof pte,
215 _kvm_pa2off(kd, pte_pa)) != sizeof pte)
216 goto invalid;
217
218 if ((pte & PG_V) == 0)
219 goto invalid;
220 *pa = (pte & PG_FRAME) + offset;
221 return (kd->nbpg - (int)offset);
222
223 invalid:
224 _kvm_err(kd, 0, "invalid address (%lx)", va);
225 return (0);
226 }
227
228 /*
229 * Translate a physical address to a file-offset in the crash-dump.
230 */
231 off_t
_kvm_pa2off(kvm_t * kd,paddr_t pa)232 _kvm_pa2off(kvm_t *kd, paddr_t pa)
233 {
234 return ((off_t)(kd->dump_off + pa));
235 }
236