kvm_i386.c revision 331722 
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 * 4. 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
34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD: stable/11/lib/libkvm/kvm_i386.c 331722 2018-03-29 02:50:57Z eadler $");
36
37#if defined(LIBC_SCCS) && !defined(lint)
38#if 0
39static char sccsid[] = "@(#)kvm_hp300.c	8.1 (Berkeley) 6/4/93";
40#endif
41#endif /* LIBC_SCCS and not lint */
42
43/*
44 * i386 machine dependent routines for kvm.  Hopefully, the forthcoming
45 * vm code will one day obsolete this module.
46 */
47
48#include <sys/param.h>
49#include <sys/endian.h>
50#include <stdint.h>
51#include <stdlib.h>
52#include <string.h>
53#include <unistd.h>
54#include <kvm.h>
55
56#ifdef __i386__
57#include <machine/vmparam.h>		/* For KERNBASE. */
58#endif
59
60#include <limits.h>
61
62#include "kvm_private.h"
63#include "kvm_i386.h"
64
65struct vmstate {
66	void		*PTD;
67	int		pae;
68	size_t		phnum;
69	GElf_Phdr	*phdr;
70};
71
72/*
73 * Translate a physical memory address to a file-offset in the crash-dump.
74 */
75static size_t
76_kvm_pa2off(kvm_t *kd, uint64_t pa, off_t *ofs)
77{
78	struct vmstate *vm = kd->vmst;
79	GElf_Phdr *p;
80	size_t n;
81
82	if (kd->rawdump) {
83		*ofs = pa;
84		return (I386_PAGE_SIZE - (pa & I386_PAGE_MASK));
85	}
86
87	p = vm->phdr;
88	n = vm->phnum;
89	while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
90		p++, n--;
91	if (n == 0)
92		return (0);
93	*ofs = (pa - p->p_paddr) + p->p_offset;
94	return (I386_PAGE_SIZE - (pa & I386_PAGE_MASK));
95}
96
97static void
98_i386_freevtop(kvm_t *kd)
99{
100	struct vmstate *vm = kd->vmst;
101
102	if (vm->PTD)
103		free(vm->PTD);
104	free(vm->phdr);
105	free(vm);
106	kd->vmst = NULL;
107}
108
109static int
110_i386_probe(kvm_t *kd)
111{
112
113	return (_kvm_probe_elf_kernel(kd, ELFCLASS32, EM_386) &&
114	    !_kvm_is_minidump(kd));
115}
116
117static int
118_i386_initvtop(kvm_t *kd)
119{
120	struct kvm_nlist nl[2];
121	i386_physaddr_t pa;
122	kvaddr_t kernbase;
123	char		*PTD;
124	int		i;
125
126	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(struct vmstate));
127	if (kd->vmst == NULL) {
128		_kvm_err(kd, kd->program, "cannot allocate vm");
129		return (-1);
130	}
131	kd->vmst->PTD = 0;
132
133	if (kd->rawdump == 0) {
134		if (_kvm_read_core_phdrs(kd, &kd->vmst->phnum,
135		    &kd->vmst->phdr) == -1)
136			return (-1);
137	}
138
139	nl[0].n_name = "kernbase";
140	nl[1].n_name = 0;
141
142	if (kvm_nlist2(kd, nl) != 0) {
143#ifdef __i386__
144		kernbase = KERNBASE;	/* for old kernels */
145#else
146		_kvm_err(kd, kd->program, "cannot resolve kernbase");
147		return (-1);
148#endif
149	} else
150		kernbase = nl[0].n_value;
151
152	nl[0].n_name = "IdlePDPT";
153	nl[1].n_name = 0;
154
155	if (kvm_nlist2(kd, nl) == 0) {
156		i386_physaddr_pae_t pa64;
157
158		if (kvm_read2(kd, (nl[0].n_value - kernbase), &pa,
159		    sizeof(pa)) != sizeof(pa)) {
160			_kvm_err(kd, kd->program, "cannot read IdlePDPT");
161			return (-1);
162		}
163		pa = le32toh(pa);
164		PTD = _kvm_malloc(kd, 4 * I386_PAGE_SIZE);
165		if (PTD == NULL) {
166			_kvm_err(kd, kd->program, "cannot allocate PTD");
167			return (-1);
168		}
169		for (i = 0; i < 4; i++) {
170			if (kvm_read2(kd, pa + (i * sizeof(pa64)), &pa64,
171			    sizeof(pa64)) != sizeof(pa64)) {
172				_kvm_err(kd, kd->program, "Cannot read PDPT");
173				free(PTD);
174				return (-1);
175			}
176			pa64 = le64toh(pa64);
177			if (kvm_read2(kd, pa64 & I386_PG_FRAME_PAE,
178			    PTD + (i * I386_PAGE_SIZE), I386_PAGE_SIZE) !=
179			    I386_PAGE_SIZE) {
180				_kvm_err(kd, kd->program, "cannot read PDPT");
181				free(PTD);
182				return (-1);
183			}
184		}
185		kd->vmst->PTD = PTD;
186		kd->vmst->pae = 1;
187	} else {
188		nl[0].n_name = "IdlePTD";
189		nl[1].n_name = 0;
190
191		if (kvm_nlist2(kd, nl) != 0) {
192			_kvm_err(kd, kd->program, "bad namelist");
193			return (-1);
194		}
195		if (kvm_read2(kd, (nl[0].n_value - kernbase), &pa,
196		    sizeof(pa)) != sizeof(pa)) {
197			_kvm_err(kd, kd->program, "cannot read IdlePTD");
198			return (-1);
199		}
200		pa = le32toh(pa);
201		PTD = _kvm_malloc(kd, I386_PAGE_SIZE);
202		if (PTD == NULL) {
203			_kvm_err(kd, kd->program, "cannot allocate PTD");
204			return (-1);
205		}
206		if (kvm_read2(kd, pa, PTD, I386_PAGE_SIZE) != I386_PAGE_SIZE) {
207			_kvm_err(kd, kd->program, "cannot read PTD");
208			return (-1);
209		}
210		kd->vmst->PTD = PTD;
211		kd->vmst->pae = 0;
212	}
213	return (0);
214}
215
216static int
217_i386_vatop(kvm_t *kd, kvaddr_t va, off_t *pa)
218{
219	struct vmstate *vm;
220	i386_physaddr_t offset;
221	i386_physaddr_t pte_pa;
222	i386_pde_t pde;
223	i386_pte_t pte;
224	kvaddr_t pdeindex;
225	kvaddr_t pteindex;
226	size_t s;
227	i386_physaddr_t a;
228	off_t ofs;
229	i386_pde_t *PTD;
230
231	vm = kd->vmst;
232	PTD = (i386_pde_t *)vm->PTD;
233	offset = va & I386_PAGE_MASK;
234
235	/*
236	 * If we are initializing (kernel page table descriptor pointer
237	 * not yet set) then return pa == va to avoid infinite recursion.
238	 */
239	if (PTD == NULL) {
240		s = _kvm_pa2off(kd, va, pa);
241		if (s == 0) {
242			_kvm_err(kd, kd->program,
243			    "_i386_vatop: bootstrap data not in dump");
244			goto invalid;
245		} else
246			return (I386_PAGE_SIZE - offset);
247	}
248
249	pdeindex = va >> I386_PDRSHIFT;
250	pde = le32toh(PTD[pdeindex]);
251	if ((pde & I386_PG_V) == 0) {
252		_kvm_err(kd, kd->program, "_i386_vatop: pde not valid");
253		goto invalid;
254	}
255
256	if (pde & I386_PG_PS) {
257		/*
258		 * No second-level page table; ptd describes one 4MB
259		 * page.  (We assume that the kernel wouldn't set
260		 * PG_PS without enabling it cr0).
261		 */
262		offset = va & I386_PAGE_PS_MASK;
263		a = (pde & I386_PG_PS_FRAME) + offset;
264		s = _kvm_pa2off(kd, a, pa);
265		if (s == 0) {
266			_kvm_err(kd, kd->program,
267			    "_i386_vatop: 4MB page address not in dump");
268			goto invalid;
269		}
270		return (I386_NBPDR - offset);
271	}
272
273	pteindex = (va >> I386_PAGE_SHIFT) & (I386_NPTEPG - 1);
274	pte_pa = (pde & I386_PG_FRAME) + (pteindex * sizeof(pte));
275
276	s = _kvm_pa2off(kd, pte_pa, &ofs);
277	if (s < sizeof(pte)) {
278		_kvm_err(kd, kd->program, "_i386_vatop: pte_pa not found");
279		goto invalid;
280	}
281
282	/* XXX This has to be a physical address read, kvm_read is virtual */
283	if (pread(kd->pmfd, &pte, sizeof(pte), ofs) != sizeof(pte)) {
284		_kvm_syserr(kd, kd->program, "_i386_vatop: pread");
285		goto invalid;
286	}
287	pte = le32toh(pte);
288	if ((pte & I386_PG_V) == 0) {
289		_kvm_err(kd, kd->program, "_kvm_kvatop: pte not valid");
290		goto invalid;
291	}
292
293	a = (pte & I386_PG_FRAME) + offset;
294	s = _kvm_pa2off(kd, a, pa);
295	if (s == 0) {
296		_kvm_err(kd, kd->program, "_i386_vatop: address not in dump");
297		goto invalid;
298	} else
299		return (I386_PAGE_SIZE - offset);
300
301invalid:
302	_kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
303	return (0);
304}
305
306static int
307_i386_vatop_pae(kvm_t *kd, kvaddr_t va, off_t *pa)
308{
309	struct vmstate *vm;
310	i386_physaddr_pae_t offset;
311	i386_physaddr_pae_t pte_pa;
312	i386_pde_pae_t pde;
313	i386_pte_pae_t pte;
314	kvaddr_t pdeindex;
315	kvaddr_t pteindex;
316	size_t s;
317	i386_physaddr_pae_t a;
318	off_t ofs;
319	i386_pde_pae_t *PTD;
320
321	vm = kd->vmst;
322	PTD = (i386_pde_pae_t *)vm->PTD;
323	offset = va & I386_PAGE_MASK;
324
325	/*
326	 * If we are initializing (kernel page table descriptor pointer
327	 * not yet set) then return pa == va to avoid infinite recursion.
328	 */
329	if (PTD == NULL) {
330		s = _kvm_pa2off(kd, va, pa);
331		if (s == 0) {
332			_kvm_err(kd, kd->program,
333			    "_i386_vatop_pae: bootstrap data not in dump");
334			goto invalid;
335		} else
336			return (I386_PAGE_SIZE - offset);
337	}
338
339	pdeindex = va >> I386_PDRSHIFT_PAE;
340	pde = le64toh(PTD[pdeindex]);
341	if ((pde & I386_PG_V) == 0) {
342		_kvm_err(kd, kd->program, "_kvm_kvatop_pae: pde not valid");
343		goto invalid;
344	}
345
346	if (pde & I386_PG_PS) {
347		/*
348		 * No second-level page table; ptd describes one 2MB
349		 * page.  (We assume that the kernel wouldn't set
350		 * PG_PS without enabling it cr0).
351		 */
352		offset = va & I386_PAGE_PS_MASK_PAE;
353		a = (pde & I386_PG_PS_FRAME_PAE) + offset;
354		s = _kvm_pa2off(kd, a, pa);
355		if (s == 0) {
356			_kvm_err(kd, kd->program,
357			    "_i386_vatop: 2MB page address not in dump");
358			goto invalid;
359		}
360		return (I386_NBPDR_PAE - offset);
361	}
362
363	pteindex = (va >> I386_PAGE_SHIFT) & (I386_NPTEPG_PAE - 1);
364	pte_pa = (pde & I386_PG_FRAME_PAE) + (pteindex * sizeof(pde));
365
366	s = _kvm_pa2off(kd, pte_pa, &ofs);
367	if (s < sizeof(pte)) {
368		_kvm_err(kd, kd->program, "_i386_vatop_pae: pdpe_pa not found");
369		goto invalid;
370	}
371
372	/* XXX This has to be a physical address read, kvm_read is virtual */
373	if (pread(kd->pmfd, &pte, sizeof(pte), ofs) != sizeof(pte)) {
374		_kvm_syserr(kd, kd->program, "_i386_vatop_pae: read");
375		goto invalid;
376	}
377	pte = le64toh(pte);
378	if ((pte & I386_PG_V) == 0) {
379		_kvm_err(kd, kd->program, "_i386_vatop_pae: pte not valid");
380		goto invalid;
381	}
382
383	a = (pte & I386_PG_FRAME_PAE) + offset;
384	s = _kvm_pa2off(kd, a, pa);
385	if (s == 0) {
386		_kvm_err(kd, kd->program,
387		    "_i386_vatop_pae: address not in dump");
388		goto invalid;
389	} else
390		return (I386_PAGE_SIZE - offset);
391
392invalid:
393	_kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
394	return (0);
395}
396
397static int
398_i386_kvatop(kvm_t *kd, kvaddr_t va, off_t *pa)
399{
400
401	if (ISALIVE(kd)) {
402		_kvm_err(kd, 0, "vatop called in live kernel!");
403		return (0);
404	}
405	if (kd->vmst->pae)
406		return (_i386_vatop_pae(kd, va, pa));
407	else
408		return (_i386_vatop(kd, va, pa));
409}
410
411int
412_i386_native(kvm_t *kd __unused)
413{
414
415#ifdef __i386__
416	return (1);
417#else
418	return (0);
419#endif
420}
421
422static struct kvm_arch kvm_i386 = {
423	.ka_probe = _i386_probe,
424	.ka_initvtop = _i386_initvtop,
425	.ka_freevtop = _i386_freevtop,
426	.ka_kvatop = _i386_kvatop,
427	.ka_native = _i386_native,
428};
429
430KVM_ARCH(kvm_i386);
431