kvm_amd64.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 1992, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software developed by the Computer Systems
8 * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
9 * BG 91-66 and contributed to Berkeley.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include <sys/cdefs.h>
37__FBSDID("$FreeBSD: stable/11/lib/libkvm/kvm_amd64.c 330897 2018-03-14 03:19:51Z eadler $");
38
39#if defined(LIBC_SCCS) && !defined(lint)
40#if 0
41static char sccsid[] = "@(#)kvm_hp300.c	8.1 (Berkeley) 6/4/93";
42#endif
43#endif /* LIBC_SCCS and not lint */
44
45/*
46 * AMD64 machine dependent routines for kvm.  Hopefully, the forthcoming
47 * vm code will one day obsolete this module.
48 */
49
50#include <sys/param.h>
51#include <sys/endian.h>
52#include <stdint.h>
53#include <stdlib.h>
54#include <string.h>
55#include <unistd.h>
56#include <kvm.h>
57
58#include <limits.h>
59
60#include "kvm_private.h"
61#include "kvm_amd64.h"
62
63struct vmstate {
64	size_t		phnum;
65	GElf_Phdr	*phdr;
66	amd64_pml4e_t	*PML4;
67};
68
69/*
70 * Translate a physical memory address to a file-offset in the crash-dump.
71 */
72static size_t
73_kvm_pa2off(kvm_t *kd, uint64_t pa, off_t *ofs)
74{
75	struct vmstate *vm = kd->vmst;
76	GElf_Phdr *p;
77	size_t n;
78
79	if (kd->rawdump) {
80		*ofs = pa;
81		return (AMD64_PAGE_SIZE - (pa & AMD64_PAGE_MASK));
82	}
83
84	p = vm->phdr;
85	n = vm->phnum;
86	while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
87		p++, n--;
88	if (n == 0)
89		return (0);
90	*ofs = (pa - p->p_paddr) + p->p_offset;
91	return (AMD64_PAGE_SIZE - (pa & AMD64_PAGE_MASK));
92}
93
94static void
95_amd64_freevtop(kvm_t *kd)
96{
97	struct vmstate *vm = kd->vmst;
98
99	if (vm->PML4)
100		free(vm->PML4);
101	free(vm->phdr);
102	free(vm);
103	kd->vmst = NULL;
104}
105
106static int
107_amd64_probe(kvm_t *kd)
108{
109
110	return (_kvm_probe_elf_kernel(kd, ELFCLASS64, EM_X86_64) &&
111	    !_kvm_is_minidump(kd));
112}
113
114static int
115_amd64_initvtop(kvm_t *kd)
116{
117	struct kvm_nlist nl[2];
118	amd64_physaddr_t pa;
119	kvaddr_t kernbase;
120	amd64_pml4e_t *PML4;
121
122	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
123	if (kd->vmst == NULL) {
124		_kvm_err(kd, kd->program, "cannot allocate vm");
125		return (-1);
126	}
127	kd->vmst->PML4 = 0;
128
129	if (kd->rawdump == 0) {
130		if (_kvm_read_core_phdrs(kd, &kd->vmst->phnum,
131		    &kd->vmst->phdr) == -1)
132			return (-1);
133	}
134
135	nl[0].n_name = "kernbase";
136	nl[1].n_name = 0;
137
138	if (kvm_nlist2(kd, nl) != 0) {
139		_kvm_err(kd, kd->program, "bad namelist - no kernbase");
140		return (-1);
141	}
142	kernbase = nl[0].n_value;
143
144	nl[0].n_name = "KPML4phys";
145	nl[1].n_name = 0;
146
147	if (kvm_nlist2(kd, nl) != 0) {
148		_kvm_err(kd, kd->program, "bad namelist - no KPML4phys");
149		return (-1);
150	}
151	if (kvm_read2(kd, (nl[0].n_value - kernbase), &pa, sizeof(pa)) !=
152	    sizeof(pa)) {
153		_kvm_err(kd, kd->program, "cannot read KPML4phys");
154		return (-1);
155	}
156	pa = le64toh(pa);
157	PML4 = _kvm_malloc(kd, AMD64_PAGE_SIZE);
158	if (PML4 == NULL) {
159		_kvm_err(kd, kd->program, "cannot allocate PML4");
160		return (-1);
161	}
162	if (kvm_read2(kd, pa, PML4, AMD64_PAGE_SIZE) != AMD64_PAGE_SIZE) {
163		_kvm_err(kd, kd->program, "cannot read KPML4phys");
164		free(PML4);
165		return (-1);
166	}
167	kd->vmst->PML4 = PML4;
168	return (0);
169}
170
171static int
172_amd64_vatop(kvm_t *kd, kvaddr_t va, off_t *pa)
173{
174	struct vmstate *vm;
175	amd64_physaddr_t offset;
176	amd64_physaddr_t pdpe_pa;
177	amd64_physaddr_t pde_pa;
178	amd64_physaddr_t pte_pa;
179	amd64_pml4e_t pml4e;
180	amd64_pdpe_t pdpe;
181	amd64_pde_t pde;
182	amd64_pte_t pte;
183	kvaddr_t pml4eindex;
184	kvaddr_t pdpeindex;
185	kvaddr_t pdeindex;
186	kvaddr_t pteindex;
187	amd64_physaddr_t a;
188	off_t ofs;
189	size_t s;
190
191	vm = kd->vmst;
192	offset = va & AMD64_PAGE_MASK;
193
194	/*
195	 * If we are initializing (kernel page table descriptor pointer
196	 * not yet set) then return pa == va to avoid infinite recursion.
197	 */
198	if (vm->PML4 == NULL) {
199		s = _kvm_pa2off(kd, va, pa);
200		if (s == 0) {
201			_kvm_err(kd, kd->program,
202			    "_amd64_vatop: bootstrap data not in dump");
203			goto invalid;
204		} else
205			return (AMD64_PAGE_SIZE - offset);
206	}
207
208	pml4eindex = (va >> AMD64_PML4SHIFT) & (AMD64_NPML4EPG - 1);
209	pml4e = le64toh(vm->PML4[pml4eindex]);
210	if ((pml4e & AMD64_PG_V) == 0) {
211		_kvm_err(kd, kd->program, "_amd64_vatop: pml4e not valid");
212		goto invalid;
213	}
214
215	pdpeindex = (va >> AMD64_PDPSHIFT) & (AMD64_NPDPEPG - 1);
216	pdpe_pa = (pml4e & AMD64_PG_FRAME) + (pdpeindex * sizeof(amd64_pdpe_t));
217
218	s = _kvm_pa2off(kd, pdpe_pa, &ofs);
219	if (s < sizeof(pdpe)) {
220		_kvm_err(kd, kd->program, "_amd64_vatop: pdpe_pa not found");
221		goto invalid;
222	}
223	if (pread(kd->pmfd, &pdpe, sizeof(pdpe), ofs) != sizeof(pdpe)) {
224		_kvm_syserr(kd, kd->program, "_amd64_vatop: read pdpe");
225		goto invalid;
226	}
227	pdpe = le64toh(pdpe);
228	if ((pdpe & AMD64_PG_V) == 0) {
229		_kvm_err(kd, kd->program, "_amd64_vatop: pdpe not valid");
230		goto invalid;
231	}
232
233	if (pdpe & AMD64_PG_PS) {
234		/*
235		 * No next-level page table; pdpe describes one 1GB page.
236		 */
237		a = (pdpe & AMD64_PG_1GB_FRAME) + (va & AMD64_PDPMASK);
238		s = _kvm_pa2off(kd, a, pa);
239		if (s == 0) {
240			_kvm_err(kd, kd->program,
241			    "_amd64_vatop: 1GB page address not in dump");
242			goto invalid;
243		} else
244			return (AMD64_NBPDP - (va & AMD64_PDPMASK));
245	}
246
247	pdeindex = (va >> AMD64_PDRSHIFT) & (AMD64_NPDEPG - 1);
248	pde_pa = (pdpe & AMD64_PG_FRAME) + (pdeindex * sizeof(amd64_pde_t));
249
250	s = _kvm_pa2off(kd, pde_pa, &ofs);
251	if (s < sizeof(pde)) {
252		_kvm_syserr(kd, kd->program, "_amd64_vatop: pde_pa not found");
253		goto invalid;
254	}
255	if (pread(kd->pmfd, &pde, sizeof(pde), ofs) != sizeof(pde)) {
256		_kvm_syserr(kd, kd->program, "_amd64_vatop: read pde");
257		goto invalid;
258	}
259	pde = le64toh(pde);
260	if ((pde & AMD64_PG_V) == 0) {
261		_kvm_err(kd, kd->program, "_amd64_vatop: pde not valid");
262		goto invalid;
263	}
264
265	if (pde & AMD64_PG_PS) {
266		/*
267		 * No final-level page table; pde describes one 2MB page.
268		 */
269		a = (pde & AMD64_PG_PS_FRAME) + (va & AMD64_PDRMASK);
270		s = _kvm_pa2off(kd, a, pa);
271		if (s == 0) {
272			_kvm_err(kd, kd->program,
273			    "_amd64_vatop: 2MB page address not in dump");
274			goto invalid;
275		} else
276			return (AMD64_NBPDR - (va & AMD64_PDRMASK));
277	}
278
279	pteindex = (va >> AMD64_PAGE_SHIFT) & (AMD64_NPTEPG - 1);
280	pte_pa = (pde & AMD64_PG_FRAME) + (pteindex * sizeof(amd64_pte_t));
281
282	s = _kvm_pa2off(kd, pte_pa, &ofs);
283	if (s < sizeof(pte)) {
284		_kvm_err(kd, kd->program, "_amd64_vatop: pte_pa not found");
285		goto invalid;
286	}
287	if (pread(kd->pmfd, &pte, sizeof(pte), ofs) != sizeof(pte)) {
288		_kvm_syserr(kd, kd->program, "_amd64_vatop: read");
289		goto invalid;
290	}
291	if ((pte & AMD64_PG_V) == 0) {
292		_kvm_err(kd, kd->program, "_amd64_vatop: pte not valid");
293		goto invalid;
294	}
295
296	a = (pte & AMD64_PG_FRAME) + offset;
297	s = _kvm_pa2off(kd, a, pa);
298	if (s == 0) {
299		_kvm_err(kd, kd->program, "_amd64_vatop: address not in dump");
300		goto invalid;
301	} else
302		return (AMD64_PAGE_SIZE - offset);
303
304invalid:
305	_kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
306	return (0);
307}
308
309static int
310_amd64_kvatop(kvm_t *kd, kvaddr_t va, off_t *pa)
311{
312
313	if (ISALIVE(kd)) {
314		_kvm_err(kd, 0, "kvm_kvatop called in live kernel!");
315		return (0);
316	}
317	return (_amd64_vatop(kd, va, pa));
318}
319
320int
321_amd64_native(kvm_t *kd __unused)
322{
323
324#ifdef __amd64__
325	return (1);
326#else
327	return (0);
328#endif
329}
330
331static struct kvm_arch kvm_amd64 = {
332	.ka_probe = _amd64_probe,
333	.ka_initvtop = _amd64_initvtop,
334	.ka_freevtop = _amd64_freevtop,
335	.ka_kvatop = _amd64_kvatop,
336	.ka_native = _amd64_native,
337};
338
339KVM_ARCH(kvm_amd64);
340