libkvm - Add ability to access userspace from kgdb on cores
[dragonfly.git] / lib / libkvm / kvm_i386.c
CommitLineData
984263bc
MD
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.
1de703da
MD
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 $
9f17b787 39 * $DragonFly: src/lib/libkvm/kvm_i386.c,v 1.3 2007/04/29 01:36:04 dillon Exp $
984263bc
MD
40 */
41
984263bc
MD
42/*
43 * i386 machine dependent routines for kvm. Hopefully, the forthcoming
44 * vm code will one day obsolete this module.
45 */
46
9f17b787 47#include <sys/user.h> /* MUST BE FIRST */
984263bc 48#include <sys/param.h>
984263bc
MD
49#include <sys/proc.h>
50#include <sys/stat.h>
78a7b07a
AH
51#include <sys/mman.h>
52#include <sys/elf_common.h>
984263bc 53#include <stdlib.h>
78a7b07a 54#include <string.h>
984263bc
MD
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
78a7b07a
AH
62#include <machine/elf.h>
63
984263bc
MD
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
78a7b07a 73/* minidump must be the first item! */
984263bc 74struct vmstate {
78a7b07a
AH
75 int minidump; /* 1 = minidump mode */
76 void *mmapbase;
77 size_t mmapsize;
78 void *PTD;
984263bc
MD
79};
80
78a7b07a
AH
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 */
86static 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 */
115static 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
984263bc
MD
138void
139_kvm_freevtop(kvm_t *kd)
140{
78a7b07a
AH
141 struct vmstate *vm = kd->vmst;
142
143 if (kd->vmst->minidump) {
144 _kvm_minidump_freevtop(kd);
145 return;
984263bc 146 }
78a7b07a
AH
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;
984263bc
MD
154}
155
156int
157_kvm_initvtop(kvm_t *kd)
158{
984263bc
MD
159 struct nlist nlist[2];
160 u_long pa;
161 u_long kernbase;
78a7b07a
AH
162 char *PTD;
163 Elf_Ehdr *ehdr;
164 size_t hdrsz;
165 char minihdr[8];
3f1be088 166 struct pcb dumppcb;
984263bc 167
78a7b07a
AH
168 if (pread(kd->pmfd, &minihdr, 8, 0) == 8)
169 if (memcmp(&minihdr, "minidump", 8) == 0)
170 return (_kvm_minidump_initvtop(kd));
171
172 kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
173 if (kd->vmst == 0) {
984263bc
MD
174 _kvm_err(kd, kd->program, "cannot allocate vm");
175 return (-1);
176 }
78a7b07a
AH
177 kd->vmst->PTD = 0;
178
179 if (_kvm_maphdrs(kd, sizeof(Elf_Ehdr)) == -1)
180 return (-1);
181 /*
182 * Check if this is indeed an ELF header. If not, assume old style dump or
183 * memory layout.
184 */
185 ehdr = kd->vmst->mmapbase;
186 if (!IS_ELF(*ehdr)) {
187 kd->rawdump = 1;
188 munmap(kd->vmst->mmapbase, kd->vmst->mmapsize);
189 kd->vmst->mmapbase = NULL;
190 } else {
191 hdrsz = ehdr->e_phoff + ehdr->e_phentsize * ehdr->e_phnum;
192 if (_kvm_maphdrs(kd, hdrsz) == -1)
193 return (-1);
194 }
984263bc
MD
195
196 nlist[0].n_name = "_kernbase";
197 nlist[1].n_name = 0;
198
199 if (kvm_nlist(kd, nlist) != 0)
200 kernbase = KERNBASE; /* for old kernels */
201 else
202 kernbase = nlist[0].n_value;
203
3f1be088 204 nlist[0].n_name = "_dumppcb";
984263bc
MD
205 nlist[1].n_name = 0;
206
207 if (kvm_nlist(kd, nlist) != 0) {
208 _kvm_err(kd, kd->program, "bad namelist");
209 return (-1);
210 }
3f1be088
MD
211
212 if (kvm_read(kd, (nlist[0].n_value - kernbase), &dumppcb,
213 sizeof(dumppcb)) != sizeof(dumppcb)) {
214 _kvm_err(kd, kd->program, "cannot read dumppcb");
984263bc
MD
215 return (-1);
216 }
3f1be088
MD
217 pa = dumppcb.pcb_cr3 & PG_FRAME;
218
984263bc
MD
219 PTD = _kvm_malloc(kd, PAGE_SIZE);
220 if (kvm_read(kd, pa, PTD, PAGE_SIZE) != PAGE_SIZE) {
221 _kvm_err(kd, kd->program, "cannot read PTD");
222 return (-1);
223 }
78a7b07a 224 kd->vmst->PTD = PTD;
984263bc
MD
225 return (0);
226}
227
228static int
78a7b07a 229_kvm_vatop(kvm_t *kd, u_long va, off_t *pa)
984263bc
MD
230{
231 struct vmstate *vm;
232 u_long offset;
233 u_long pte_pa;
78a7b07a 234 u_long pde_pa;
984263bc
MD
235 pd_entry_t pde;
236 pt_entry_t pte;
237 u_long pdeindex;
238 u_long pteindex;
78a7b07a
AH
239 size_t s;
240 u_long a;
241 off_t ofs;
242 uint32_t *PTD;
984263bc 243
984263bc
MD
244
245 vm = kd->vmst;
78a7b07a 246 PTD = (uint32_t *)vm->PTD;
984263bc
MD
247 offset = va & (PAGE_SIZE - 1);
248
249 /*
250 * If we are initializing (kernel page table descriptor pointer
251 * not yet set) then return pa == va to avoid infinite recursion.
252 */
78a7b07a
AH
253 if (PTD == 0) {
254 s = _kvm_pa2off(kd, va, pa);
255 if (s == 0) {
256 _kvm_err(kd, kd->program,
257 "_kvm_vatop: bootstrap data not in dump");
258 goto invalid;
259 } else {
260 return (PAGE_SIZE - offset);
261 }
984263bc
MD
262 }
263
264 pdeindex = va >> PDRSHIFT;
78a7b07a
AH
265 pde = PTD[pdeindex];
266
267 if (((u_long)pde & PG_V) == 0) {
268 _kvm_err(kd, kd->program, "_kvm_vatop: pde not valid");
984263bc 269 goto invalid;
78a7b07a 270 }
984263bc
MD
271
272 if ((u_long)pde & PG_PS) {
273 /*
274 * No second-level page table; ptd describes one 4MB page.
275 * (We assume that the kernel wouldn't set PG_PS without enabling
276 * it cr0, and that the kernel doesn't support 36-bit physical
277 * addresses).
278 */
279#define PAGE4M_MASK (NBPDR - 1)
280#define PG_FRAME4M (~PAGE4M_MASK)
78a7b07a 281#if 0
984263bc 282 *pa = ((u_long)pde & PG_FRAME4M) + (va & PAGE4M_MASK);
78a7b07a
AH
283#endif
284 pde_pa = ((u_long)pde & PG_FRAME4M) + (va & PAGE4M_MASK);
285 s = _kvm_pa2off(kd, pde_pa, &ofs);
3f1be088 286 if (s < sizeof pde) {
78a7b07a
AH
287 _kvm_syserr(kd, kd->program,
288 "_kvm_vatop: pde_pa not found");
289 goto invalid;
290 }
291 *pa = ofs;
292
984263bc
MD
293 return (NBPDR - (va & PAGE4M_MASK));
294 }
295
296 pteindex = (va >> PAGE_SHIFT) & (NPTEPG-1);
78a7b07a
AH
297 pte_pa = ((u_long)pde & PG_FRAME) + (pteindex * sizeof(pde));
298
299 s = _kvm_pa2off(kd, pte_pa, &ofs);
3f1be088 300 if (s < sizeof pte) {
78a7b07a
AH
301 _kvm_err(kd, kd->program, "_kvm_vatop: pdpe_pa not found");
302 goto invalid;
303 }
984263bc
MD
304
305 /* XXX This has to be a physical address read, kvm_read is virtual */
78a7b07a 306 if (lseek(kd->pmfd, ofs, 0) == -1) {
984263bc
MD
307 _kvm_syserr(kd, kd->program, "_kvm_vatop: lseek");
308 goto invalid;
309 }
310 if (read(kd->pmfd, &pte, sizeof pte) != sizeof pte) {
311 _kvm_syserr(kd, kd->program, "_kvm_vatop: read");
312 goto invalid;
313 }
78a7b07a
AH
314 if (((u_long)pte & PG_V) == 0) {
315 _kvm_err(kd, kd->program, "_kvm_kvatop: pte not valid");
984263bc 316 goto invalid;
78a7b07a 317 }
984263bc 318
78a7b07a
AH
319 a = ((u_long)pte & PG_FRAME) + offset;
320 s =_kvm_pa2off(kd, a, pa);
321 if (s == 0) {
322 _kvm_err(kd, kd->program, "_kvm_vatop: address not in dump");
323 goto invalid;
324 } else
325 return (PAGE_SIZE - offset);
984263bc
MD
326
327invalid:
78a7b07a 328 _kvm_err(kd, 0, "invalid address (0x%lx)", va);
984263bc
MD
329 return (0);
330}
331
332int
78a7b07a 333_kvm_kvatop(kvm_t *kd, u_long va, off_t *pa)
984263bc 334{
78a7b07a
AH
335 if (kd->vmst->minidump)
336 return (_kvm_minidump_kvatop(kd, va, pa));
337
338 if (kvm_ishost(kd)) {
339 _kvm_err(kd, 0, "vatop called in live kernel!");
340 return (0);
341 }
342
984263bc
MD
343 return (_kvm_vatop(kd, va, pa));
344}