kvm_amd64.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_amd64.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 * AMD64 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#include <limits.h>
57
58#include "kvm_private.h"
59#include "kvm_amd64.h"
60
61struct vmstate {
62	size_t		phnum;
63	GElf_Phdr	*phdr;
64	amd64_pml4e_t	*PML4;
65};
66
67/*
68 * Translate a physical memory address to a file-offset in the crash-dump.
69 */
70static size_t
71_kvm_pa2off(kvm_t *kd, uint64_t pa, off_t *ofs)
72{
73	struct vmstate *vm = kd->vmst;
74	GElf_Phdr *p;
75	size_t n;
76
77	if (kd->rawdump) {
78		*ofs = pa;
79		return (AMD64_PAGE_SIZE - (pa & AMD64_PAGE_MASK));
80	}
81
82	p = vm->phdr;
83	n = vm->phnum;
84	while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
85		p++, n--;
86	if (n == 0)
87		return (0);
88	*ofs = (pa - p->p_paddr) + p->p_offset;
89	return (AMD64_PAGE_SIZE - (pa & AMD64_PAGE_MASK));
90}
91
92static void
93_amd64_freevtop(kvm_t *kd)
94{
95	struct vmstate *vm = kd->vmst;
96
97	if (vm->PML4)
98		free(vm->PML4);
99	free(vm->phdr);
100	free(vm);
101	kd->vmst = NULL;
102}
103
104static int
105_amd64_probe(kvm_t *kd)
106{
107
108	return (_kvm_probe_elf_kernel(kd, ELFCLASS64, EM_X86_64) &&
109	    !_kvm_is_minidump(kd));
110}
111
112static int
113_amd64_initvtop(kvm_t *kd)
114{
115	struct kvm_nlist nl[2];
116	amd64_physaddr_t pa;
117	kvaddr_t kernbase;
118	amd64_pml4e_t *PML4;
119
120	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
121	if (kd->vmst == NULL) {
122		_kvm_err(kd, kd->program, "cannot allocate vm");
123		return (-1);
124	}
125	kd->vmst->PML4 = 0;
126
127	if (kd->rawdump == 0) {
128		if (_kvm_read_core_phdrs(kd, &kd->vmst->phnum,
129		    &kd->vmst->phdr) == -1)
130			return (-1);
131	}
132
133	nl[0].n_name = "kernbase";
134	nl[1].n_name = 0;
135
136	if (kvm_nlist2(kd, nl) != 0) {
137		_kvm_err(kd, kd->program, "bad namelist - no kernbase");
138		return (-1);
139	}
140	kernbase = nl[0].n_value;
141
142	nl[0].n_name = "KPML4phys";
143	nl[1].n_name = 0;
144
145	if (kvm_nlist2(kd, nl) != 0) {
146		_kvm_err(kd, kd->program, "bad namelist - no KPML4phys");
147		return (-1);
148	}
149	if (kvm_read2(kd, (nl[0].n_value - kernbase), &pa, sizeof(pa)) !=
150	    sizeof(pa)) {
151		_kvm_err(kd, kd->program, "cannot read KPML4phys");
152		return (-1);
153	}
154	pa = le64toh(pa);
155	PML4 = _kvm_malloc(kd, AMD64_PAGE_SIZE);
156	if (PML4 == NULL) {
157		_kvm_err(kd, kd->program, "cannot allocate PML4");
158		return (-1);
159	}
160	if (kvm_read2(kd, pa, PML4, AMD64_PAGE_SIZE) != AMD64_PAGE_SIZE) {
161		_kvm_err(kd, kd->program, "cannot read KPML4phys");
162		free(PML4);
163		return (-1);
164	}
165	kd->vmst->PML4 = PML4;
166	return (0);
167}
168
169static int
170_amd64_vatop(kvm_t *kd, kvaddr_t va, off_t *pa)
171{
172	struct vmstate *vm;
173	amd64_physaddr_t offset;
174	amd64_physaddr_t pdpe_pa;
175	amd64_physaddr_t pde_pa;
176	amd64_physaddr_t pte_pa;
177	amd64_pml4e_t pml4e;
178	amd64_pdpe_t pdpe;
179	amd64_pde_t pde;
180	amd64_pte_t pte;
181	kvaddr_t pml4eindex;
182	kvaddr_t pdpeindex;
183	kvaddr_t pdeindex;
184	kvaddr_t pteindex;
185	amd64_physaddr_t a;
186	off_t ofs;
187	size_t s;
188
189	vm = kd->vmst;
190	offset = va & AMD64_PAGE_MASK;
191
192	/*
193	 * If we are initializing (kernel page table descriptor pointer
194	 * not yet set) then return pa == va to avoid infinite recursion.
195	 */
196	if (vm->PML4 == NULL) {
197		s = _kvm_pa2off(kd, va, pa);
198		if (s == 0) {
199			_kvm_err(kd, kd->program,
200			    "_amd64_vatop: bootstrap data not in dump");
201			goto invalid;
202		} else
203			return (AMD64_PAGE_SIZE - offset);
204	}
205
206	pml4eindex = (va >> AMD64_PML4SHIFT) & (AMD64_NPML4EPG - 1);
207	pml4e = le64toh(vm->PML4[pml4eindex]);
208	if ((pml4e & AMD64_PG_V) == 0) {
209		_kvm_err(kd, kd->program, "_amd64_vatop: pml4e not valid");
210		goto invalid;
211	}
212
213	pdpeindex = (va >> AMD64_PDPSHIFT) & (AMD64_NPDPEPG - 1);
214	pdpe_pa = (pml4e & AMD64_PG_FRAME) + (pdpeindex * sizeof(amd64_pdpe_t));
215
216	s = _kvm_pa2off(kd, pdpe_pa, &ofs);
217	if (s < sizeof(pdpe)) {
218		_kvm_err(kd, kd->program, "_amd64_vatop: pdpe_pa not found");
219		goto invalid;
220	}
221	if (pread(kd->pmfd, &pdpe, sizeof(pdpe), ofs) != sizeof(pdpe)) {
222		_kvm_syserr(kd, kd->program, "_amd64_vatop: read pdpe");
223		goto invalid;
224	}
225	pdpe = le64toh(pdpe);
226	if ((pdpe & AMD64_PG_V) == 0) {
227		_kvm_err(kd, kd->program, "_amd64_vatop: pdpe not valid");
228		goto invalid;
229	}
230
231	if (pdpe & AMD64_PG_PS) {
232		/*
233		 * No next-level page table; pdpe describes one 1GB page.
234		 */
235		a = (pdpe & AMD64_PG_1GB_FRAME) + (va & AMD64_PDPMASK);
236		s = _kvm_pa2off(kd, a, pa);
237		if (s == 0) {
238			_kvm_err(kd, kd->program,
239			    "_amd64_vatop: 1GB page address not in dump");
240			goto invalid;
241		} else
242			return (AMD64_NBPDP - (va & AMD64_PDPMASK));
243	}
244
245	pdeindex = (va >> AMD64_PDRSHIFT) & (AMD64_NPDEPG - 1);
246	pde_pa = (pdpe & AMD64_PG_FRAME) + (pdeindex * sizeof(amd64_pde_t));
247
248	s = _kvm_pa2off(kd, pde_pa, &ofs);
249	if (s < sizeof(pde)) {
250		_kvm_syserr(kd, kd->program, "_amd64_vatop: pde_pa not found");
251		goto invalid;
252	}
253	if (pread(kd->pmfd, &pde, sizeof(pde), ofs) != sizeof(pde)) {
254		_kvm_syserr(kd, kd->program, "_amd64_vatop: read pde");
255		goto invalid;
256	}
257	pde = le64toh(pde);
258	if ((pde & AMD64_PG_V) == 0) {
259		_kvm_err(kd, kd->program, "_amd64_vatop: pde not valid");
260		goto invalid;
261	}
262
263	if (pde & AMD64_PG_PS) {
264		/*
265		 * No final-level page table; pde describes one 2MB page.
266		 */
267		a = (pde & AMD64_PG_PS_FRAME) + (va & AMD64_PDRMASK);
268		s = _kvm_pa2off(kd, a, pa);
269		if (s == 0) {
270			_kvm_err(kd, kd->program,
271			    "_amd64_vatop: 2MB page address not in dump");
272			goto invalid;
273		} else
274			return (AMD64_NBPDR - (va & AMD64_PDRMASK));
275	}
276
277	pteindex = (va >> AMD64_PAGE_SHIFT) & (AMD64_NPTEPG - 1);
278	pte_pa = (pde & AMD64_PG_FRAME) + (pteindex * sizeof(amd64_pte_t));
279
280	s = _kvm_pa2off(kd, pte_pa, &ofs);
281	if (s < sizeof(pte)) {
282		_kvm_err(kd, kd->program, "_amd64_vatop: pte_pa not found");
283		goto invalid;
284	}
285	if (pread(kd->pmfd, &pte, sizeof(pte), ofs) != sizeof(pte)) {
286		_kvm_syserr(kd, kd->program, "_amd64_vatop: read");
287		goto invalid;
288	}
289	if ((pte & AMD64_PG_V) == 0) {
290		_kvm_err(kd, kd->program, "_amd64_vatop: pte not valid");
291		goto invalid;
292	}
293
294	a = (pte & AMD64_PG_FRAME) + offset;
295	s = _kvm_pa2off(kd, a, pa);
296	if (s == 0) {
297		_kvm_err(kd, kd->program, "_amd64_vatop: address not in dump");
298		goto invalid;
299	} else
300		return (AMD64_PAGE_SIZE - offset);
301
302invalid:
303	_kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
304	return (0);
305}
306
307static int
308_amd64_kvatop(kvm_t *kd, kvaddr_t va, off_t *pa)
309{
310
311	if (ISALIVE(kd)) {
312		_kvm_err(kd, 0, "kvm_kvatop called in live kernel!");
313		return (0);
314	}
315	return (_amd64_vatop(kd, va, pa));
316}
317
318int
319_amd64_native(kvm_t *kd __unused)
320{
321
322#ifdef __amd64__
323	return (1);
324#else
325	return (0);
326#endif
327}
328
329static struct kvm_arch kvm_amd64 = {
330	.ka_probe = _amd64_probe,
331	.ka_initvtop = _amd64_initvtop,
332	.ka_freevtop = _amd64_freevtop,
333	.ka_kvatop = _amd64_kvatop,
334	.ka_native = _amd64_native,
335};
336
337KVM_ARCH(kvm_amd64);
338