xref: /freebsd/lib/libkvm/kvm_amd64.c (revision eb69d1f144a6fcc765d1b9d44a5ae8082353e70b)
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  * 3. 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("$FreeBSD$");
38 
39 #if defined(LIBC_SCCS) && !defined(lint)
40 #if 0
41 static 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 <vm/vm.h>
57 #include <kvm.h>
58 
59 #include <limits.h>
60 
61 #include "kvm_private.h"
62 #include "kvm_amd64.h"
63 
64 struct vmstate {
65 	size_t		phnum;
66 	GElf_Phdr	*phdr;
67 	amd64_pml4e_t	*PML4;
68 };
69 
70 /*
71  * Translate a physical memory address to a file-offset in the crash-dump.
72  */
73 static size_t
74 _kvm_pa2off(kvm_t *kd, uint64_t pa, off_t *ofs)
75 {
76 	struct vmstate *vm = kd->vmst;
77 	GElf_Phdr *p;
78 	size_t n;
79 
80 	if (kd->rawdump) {
81 		*ofs = pa;
82 		return (AMD64_PAGE_SIZE - (pa & AMD64_PAGE_MASK));
83 	}
84 
85 	p = vm->phdr;
86 	n = vm->phnum;
87 	while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
88 		p++, n--;
89 	if (n == 0)
90 		return (0);
91 	*ofs = (pa - p->p_paddr) + p->p_offset;
92 	return (AMD64_PAGE_SIZE - (pa & AMD64_PAGE_MASK));
93 }
94 
95 static void
96 _amd64_freevtop(kvm_t *kd)
97 {
98 	struct vmstate *vm = kd->vmst;
99 
100 	if (vm->PML4)
101 		free(vm->PML4);
102 	free(vm->phdr);
103 	free(vm);
104 	kd->vmst = NULL;
105 }
106 
107 static int
108 _amd64_probe(kvm_t *kd)
109 {
110 
111 	return (_kvm_probe_elf_kernel(kd, ELFCLASS64, EM_X86_64) &&
112 	    !_kvm_is_minidump(kd));
113 }
114 
115 static int
116 _amd64_initvtop(kvm_t *kd)
117 {
118 	struct kvm_nlist nl[2];
119 	amd64_physaddr_t pa;
120 	kvaddr_t kernbase;
121 	amd64_pml4e_t *PML4;
122 
123 	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
124 	if (kd->vmst == NULL) {
125 		_kvm_err(kd, kd->program, "cannot allocate vm");
126 		return (-1);
127 	}
128 	kd->vmst->PML4 = 0;
129 
130 	if (kd->rawdump == 0) {
131 		if (_kvm_read_core_phdrs(kd, &kd->vmst->phnum,
132 		    &kd->vmst->phdr) == -1)
133 			return (-1);
134 	}
135 
136 	nl[0].n_name = "kernbase";
137 	nl[1].n_name = 0;
138 
139 	if (kvm_nlist2(kd, nl) != 0) {
140 		_kvm_err(kd, kd->program, "bad namelist - no kernbase");
141 		return (-1);
142 	}
143 	kernbase = nl[0].n_value;
144 
145 	nl[0].n_name = "KPML4phys";
146 	nl[1].n_name = 0;
147 
148 	if (kvm_nlist2(kd, nl) != 0) {
149 		_kvm_err(kd, kd->program, "bad namelist - no KPML4phys");
150 		return (-1);
151 	}
152 	if (kvm_read2(kd, (nl[0].n_value - kernbase), &pa, sizeof(pa)) !=
153 	    sizeof(pa)) {
154 		_kvm_err(kd, kd->program, "cannot read KPML4phys");
155 		return (-1);
156 	}
157 	pa = le64toh(pa);
158 	PML4 = _kvm_malloc(kd, AMD64_PAGE_SIZE);
159 	if (PML4 == NULL) {
160 		_kvm_err(kd, kd->program, "cannot allocate PML4");
161 		return (-1);
162 	}
163 	if (kvm_read2(kd, pa, PML4, AMD64_PAGE_SIZE) != AMD64_PAGE_SIZE) {
164 		_kvm_err(kd, kd->program, "cannot read KPML4phys");
165 		free(PML4);
166 		return (-1);
167 	}
168 	kd->vmst->PML4 = PML4;
169 	return (0);
170 }
171 
172 static int
173 _amd64_vatop(kvm_t *kd, kvaddr_t va, off_t *pa)
174 {
175 	struct vmstate *vm;
176 	amd64_physaddr_t offset;
177 	amd64_physaddr_t pdpe_pa;
178 	amd64_physaddr_t pde_pa;
179 	amd64_physaddr_t pte_pa;
180 	amd64_pml4e_t pml4e;
181 	amd64_pdpe_t pdpe;
182 	amd64_pde_t pde;
183 	amd64_pte_t pte;
184 	kvaddr_t pml4eindex;
185 	kvaddr_t pdpeindex;
186 	kvaddr_t pdeindex;
187 	kvaddr_t pteindex;
188 	amd64_physaddr_t a;
189 	off_t ofs;
190 	size_t s;
191 
192 	vm = kd->vmst;
193 	offset = va & AMD64_PAGE_MASK;
194 
195 	/*
196 	 * If we are initializing (kernel page table descriptor pointer
197 	 * not yet set) then return pa == va to avoid infinite recursion.
198 	 */
199 	if (vm->PML4 == NULL) {
200 		s = _kvm_pa2off(kd, va, pa);
201 		if (s == 0) {
202 			_kvm_err(kd, kd->program,
203 			    "_amd64_vatop: bootstrap data not in dump");
204 			goto invalid;
205 		} else
206 			return (AMD64_PAGE_SIZE - offset);
207 	}
208 
209 	pml4eindex = (va >> AMD64_PML4SHIFT) & (AMD64_NPML4EPG - 1);
210 	pml4e = le64toh(vm->PML4[pml4eindex]);
211 	if ((pml4e & AMD64_PG_V) == 0) {
212 		_kvm_err(kd, kd->program, "_amd64_vatop: pml4e not valid");
213 		goto invalid;
214 	}
215 
216 	pdpeindex = (va >> AMD64_PDPSHIFT) & (AMD64_NPDPEPG - 1);
217 	pdpe_pa = (pml4e & AMD64_PG_FRAME) + (pdpeindex * sizeof(amd64_pdpe_t));
218 
219 	s = _kvm_pa2off(kd, pdpe_pa, &ofs);
220 	if (s < sizeof(pdpe)) {
221 		_kvm_err(kd, kd->program, "_amd64_vatop: pdpe_pa not found");
222 		goto invalid;
223 	}
224 	if (pread(kd->pmfd, &pdpe, sizeof(pdpe), ofs) != sizeof(pdpe)) {
225 		_kvm_syserr(kd, kd->program, "_amd64_vatop: read pdpe");
226 		goto invalid;
227 	}
228 	pdpe = le64toh(pdpe);
229 	if ((pdpe & AMD64_PG_V) == 0) {
230 		_kvm_err(kd, kd->program, "_amd64_vatop: pdpe not valid");
231 		goto invalid;
232 	}
233 
234 	if (pdpe & AMD64_PG_PS) {
235 		/*
236 		 * No next-level page table; pdpe describes one 1GB page.
237 		 */
238 		a = (pdpe & AMD64_PG_1GB_FRAME) + (va & AMD64_PDPMASK);
239 		s = _kvm_pa2off(kd, a, pa);
240 		if (s == 0) {
241 			_kvm_err(kd, kd->program,
242 			    "_amd64_vatop: 1GB page address not in dump");
243 			goto invalid;
244 		} else
245 			return (AMD64_NBPDP - (va & AMD64_PDPMASK));
246 	}
247 
248 	pdeindex = (va >> AMD64_PDRSHIFT) & (AMD64_NPDEPG - 1);
249 	pde_pa = (pdpe & AMD64_PG_FRAME) + (pdeindex * sizeof(amd64_pde_t));
250 
251 	s = _kvm_pa2off(kd, pde_pa, &ofs);
252 	if (s < sizeof(pde)) {
253 		_kvm_syserr(kd, kd->program, "_amd64_vatop: pde_pa not found");
254 		goto invalid;
255 	}
256 	if (pread(kd->pmfd, &pde, sizeof(pde), ofs) != sizeof(pde)) {
257 		_kvm_syserr(kd, kd->program, "_amd64_vatop: read pde");
258 		goto invalid;
259 	}
260 	pde = le64toh(pde);
261 	if ((pde & AMD64_PG_V) == 0) {
262 		_kvm_err(kd, kd->program, "_amd64_vatop: pde not valid");
263 		goto invalid;
264 	}
265 
266 	if (pde & AMD64_PG_PS) {
267 		/*
268 		 * No final-level page table; pde describes one 2MB page.
269 		 */
270 		a = (pde & AMD64_PG_PS_FRAME) + (va & AMD64_PDRMASK);
271 		s = _kvm_pa2off(kd, a, pa);
272 		if (s == 0) {
273 			_kvm_err(kd, kd->program,
274 			    "_amd64_vatop: 2MB page address not in dump");
275 			goto invalid;
276 		} else
277 			return (AMD64_NBPDR - (va & AMD64_PDRMASK));
278 	}
279 
280 	pteindex = (va >> AMD64_PAGE_SHIFT) & (AMD64_NPTEPG - 1);
281 	pte_pa = (pde & AMD64_PG_FRAME) + (pteindex * sizeof(amd64_pte_t));
282 
283 	s = _kvm_pa2off(kd, pte_pa, &ofs);
284 	if (s < sizeof(pte)) {
285 		_kvm_err(kd, kd->program, "_amd64_vatop: pte_pa not found");
286 		goto invalid;
287 	}
288 	if (pread(kd->pmfd, &pte, sizeof(pte), ofs) != sizeof(pte)) {
289 		_kvm_syserr(kd, kd->program, "_amd64_vatop: read");
290 		goto invalid;
291 	}
292 	if ((pte & AMD64_PG_V) == 0) {
293 		_kvm_err(kd, kd->program, "_amd64_vatop: pte not valid");
294 		goto invalid;
295 	}
296 
297 	a = (pte & AMD64_PG_FRAME) + offset;
298 	s = _kvm_pa2off(kd, a, pa);
299 	if (s == 0) {
300 		_kvm_err(kd, kd->program, "_amd64_vatop: address not in dump");
301 		goto invalid;
302 	} else
303 		return (AMD64_PAGE_SIZE - offset);
304 
305 invalid:
306 	_kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
307 	return (0);
308 }
309 
310 static int
311 _amd64_kvatop(kvm_t *kd, kvaddr_t va, off_t *pa)
312 {
313 
314 	if (ISALIVE(kd)) {
315 		_kvm_err(kd, 0, "kvm_kvatop called in live kernel!");
316 		return (0);
317 	}
318 	return (_amd64_vatop(kd, va, pa));
319 }
320 
321 int
322 _amd64_native(kvm_t *kd __unused)
323 {
324 
325 #ifdef __amd64__
326 	return (1);
327 #else
328 	return (0);
329 #endif
330 }
331 
332 static struct kvm_arch kvm_amd64 = {
333 	.ka_probe = _amd64_probe,
334 	.ka_initvtop = _amd64_initvtop,
335 	.ka_freevtop = _amd64_freevtop,
336 	.ka_kvatop = _amd64_kvatop,
337 	.ka_native = _amd64_native,
338 };
339 
340 KVM_ARCH(kvm_amd64);
341