xref: /freebsd/lib/libkvm/kvm_amd64.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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 __SCCSID("@(#)kvm_hp300.c	8.1 (Berkeley) 6/4/93");
39 
40 /*
41  * AMD64 machine dependent routines for kvm.  Hopefully, the forthcoming
42  * vm code will one day obsolete this module.
43  */
44 
45 #include <sys/param.h>
46 #include <sys/endian.h>
47 #include <stdint.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include <unistd.h>
51 #include <vm/vm.h>
52 #include <kvm.h>
53 
54 #include <limits.h>
55 
56 #include "kvm_private.h"
57 #include "kvm_amd64.h"
58 
59 struct vmstate {
60 	size_t		phnum;
61 	GElf_Phdr	*phdr;
62 	amd64_pml4e_t	*PML4;
63 };
64 
65 /*
66  * Translate a physical memory address to a file-offset in the crash-dump.
67  */
68 static size_t
69 _kvm_pa2off(kvm_t *kd, uint64_t pa, off_t *ofs)
70 {
71 	struct vmstate *vm = kd->vmst;
72 	GElf_Phdr *p;
73 	size_t n;
74 
75 	if (kd->rawdump) {
76 		*ofs = pa;
77 		return (AMD64_PAGE_SIZE - (pa & AMD64_PAGE_MASK));
78 	}
79 
80 	p = vm->phdr;
81 	n = vm->phnum;
82 	while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
83 		p++, n--;
84 	if (n == 0)
85 		return (0);
86 	*ofs = (pa - p->p_paddr) + p->p_offset;
87 	return (AMD64_PAGE_SIZE - (pa & AMD64_PAGE_MASK));
88 }
89 
90 static void
91 _amd64_freevtop(kvm_t *kd)
92 {
93 	struct vmstate *vm = kd->vmst;
94 
95 	if (vm->PML4)
96 		free(vm->PML4);
97 	free(vm->phdr);
98 	free(vm);
99 	kd->vmst = NULL;
100 }
101 
102 static int
103 _amd64_probe(kvm_t *kd)
104 {
105 
106 	return (_kvm_probe_elf_kernel(kd, ELFCLASS64, EM_X86_64) &&
107 	    !_kvm_is_minidump(kd));
108 }
109 
110 static int
111 _amd64_initvtop(kvm_t *kd)
112 {
113 	struct kvm_nlist nl[2];
114 	amd64_physaddr_t pa;
115 	kvaddr_t kernbase;
116 	amd64_pml4e_t *PML4;
117 
118 	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
119 	if (kd->vmst == NULL) {
120 		_kvm_err(kd, kd->program, "cannot allocate vm");
121 		return (-1);
122 	}
123 	kd->vmst->PML4 = 0;
124 
125 	if (kd->rawdump == 0) {
126 		if (_kvm_read_core_phdrs(kd, &kd->vmst->phnum,
127 		    &kd->vmst->phdr) == -1)
128 			return (-1);
129 	}
130 
131 	nl[0].n_name = "kernbase";
132 	nl[1].n_name = 0;
133 
134 	if (kvm_nlist2(kd, nl) != 0) {
135 		_kvm_err(kd, kd->program, "bad namelist - no kernbase");
136 		return (-1);
137 	}
138 	kernbase = nl[0].n_value;
139 
140 	nl[0].n_name = "KPML4phys";
141 	nl[1].n_name = 0;
142 
143 	if (kvm_nlist2(kd, nl) != 0) {
144 		_kvm_err(kd, kd->program, "bad namelist - no KPML4phys");
145 		return (-1);
146 	}
147 	if (kvm_read2(kd, (nl[0].n_value - kernbase), &pa, sizeof(pa)) !=
148 	    sizeof(pa)) {
149 		_kvm_err(kd, kd->program, "cannot read KPML4phys");
150 		return (-1);
151 	}
152 	pa = le64toh(pa);
153 	PML4 = _kvm_malloc(kd, AMD64_PAGE_SIZE);
154 	if (PML4 == NULL) {
155 		_kvm_err(kd, kd->program, "cannot allocate PML4");
156 		return (-1);
157 	}
158 	if (kvm_read2(kd, pa, PML4, AMD64_PAGE_SIZE) != AMD64_PAGE_SIZE) {
159 		_kvm_err(kd, kd->program, "cannot read KPML4phys");
160 		free(PML4);
161 		return (-1);
162 	}
163 	kd->vmst->PML4 = PML4;
164 	return (0);
165 }
166 
167 static int
168 _amd64_vatop(kvm_t *kd, kvaddr_t va, off_t *pa)
169 {
170 	struct vmstate *vm;
171 	amd64_physaddr_t offset;
172 	amd64_physaddr_t pdpe_pa;
173 	amd64_physaddr_t pde_pa;
174 	amd64_physaddr_t pte_pa;
175 	amd64_pml4e_t pml4e;
176 	amd64_pdpe_t pdpe;
177 	amd64_pde_t pde;
178 	amd64_pte_t pte;
179 	kvaddr_t pml4eindex;
180 	kvaddr_t pdpeindex;
181 	kvaddr_t pdeindex;
182 	kvaddr_t pteindex;
183 	amd64_physaddr_t a;
184 	off_t ofs;
185 	size_t s;
186 
187 	vm = kd->vmst;
188 	offset = va & AMD64_PAGE_MASK;
189 
190 	/*
191 	 * If we are initializing (kernel page table descriptor pointer
192 	 * not yet set) then return pa == va to avoid infinite recursion.
193 	 */
194 	if (vm->PML4 == NULL) {
195 		s = _kvm_pa2off(kd, va, pa);
196 		if (s == 0) {
197 			_kvm_err(kd, kd->program,
198 			    "_amd64_vatop: bootstrap data not in dump");
199 			goto invalid;
200 		} else
201 			return (AMD64_PAGE_SIZE - offset);
202 	}
203 
204 	pml4eindex = (va >> AMD64_PML4SHIFT) & (AMD64_NPML4EPG - 1);
205 	pml4e = le64toh(vm->PML4[pml4eindex]);
206 	if ((pml4e & AMD64_PG_V) == 0) {
207 		_kvm_err(kd, kd->program, "_amd64_vatop: pml4e not valid");
208 		goto invalid;
209 	}
210 
211 	pdpeindex = (va >> AMD64_PDPSHIFT) & (AMD64_NPDPEPG - 1);
212 	pdpe_pa = (pml4e & AMD64_PG_FRAME) + (pdpeindex * sizeof(amd64_pdpe_t));
213 
214 	s = _kvm_pa2off(kd, pdpe_pa, &ofs);
215 	if (s < sizeof(pdpe)) {
216 		_kvm_err(kd, kd->program, "_amd64_vatop: pdpe_pa not found");
217 		goto invalid;
218 	}
219 	if (pread(kd->pmfd, &pdpe, sizeof(pdpe), ofs) != sizeof(pdpe)) {
220 		_kvm_syserr(kd, kd->program, "_amd64_vatop: read pdpe");
221 		goto invalid;
222 	}
223 	pdpe = le64toh(pdpe);
224 	if ((pdpe & AMD64_PG_V) == 0) {
225 		_kvm_err(kd, kd->program, "_amd64_vatop: pdpe not valid");
226 		goto invalid;
227 	}
228 
229 	if (pdpe & AMD64_PG_PS) {
230 		/*
231 		 * No next-level page table; pdpe describes one 1GB page.
232 		 */
233 		a = (pdpe & AMD64_PG_1GB_FRAME) + (va & AMD64_PDPMASK);
234 		s = _kvm_pa2off(kd, a, pa);
235 		if (s == 0) {
236 			_kvm_err(kd, kd->program,
237 			    "_amd64_vatop: 1GB page address not in dump");
238 			goto invalid;
239 		} else
240 			return (AMD64_NBPDP - (va & AMD64_PDPMASK));
241 	}
242 
243 	pdeindex = (va >> AMD64_PDRSHIFT) & (AMD64_NPDEPG - 1);
244 	pde_pa = (pdpe & AMD64_PG_FRAME) + (pdeindex * sizeof(amd64_pde_t));
245 
246 	s = _kvm_pa2off(kd, pde_pa, &ofs);
247 	if (s < sizeof(pde)) {
248 		_kvm_syserr(kd, kd->program, "_amd64_vatop: pde_pa not found");
249 		goto invalid;
250 	}
251 	if (pread(kd->pmfd, &pde, sizeof(pde), ofs) != sizeof(pde)) {
252 		_kvm_syserr(kd, kd->program, "_amd64_vatop: read pde");
253 		goto invalid;
254 	}
255 	pde = le64toh(pde);
256 	if ((pde & AMD64_PG_V) == 0) {
257 		_kvm_err(kd, kd->program, "_amd64_vatop: pde not valid");
258 		goto invalid;
259 	}
260 
261 	if (pde & AMD64_PG_PS) {
262 		/*
263 		 * No final-level page table; pde describes one 2MB page.
264 		 */
265 		a = (pde & AMD64_PG_PS_FRAME) + (va & AMD64_PDRMASK);
266 		s = _kvm_pa2off(kd, a, pa);
267 		if (s == 0) {
268 			_kvm_err(kd, kd->program,
269 			    "_amd64_vatop: 2MB page address not in dump");
270 			goto invalid;
271 		} else
272 			return (AMD64_NBPDR - (va & AMD64_PDRMASK));
273 	}
274 
275 	pteindex = (va >> AMD64_PAGE_SHIFT) & (AMD64_NPTEPG - 1);
276 	pte_pa = (pde & AMD64_PG_FRAME) + (pteindex * sizeof(amd64_pte_t));
277 
278 	s = _kvm_pa2off(kd, pte_pa, &ofs);
279 	if (s < sizeof(pte)) {
280 		_kvm_err(kd, kd->program, "_amd64_vatop: pte_pa not found");
281 		goto invalid;
282 	}
283 	if (pread(kd->pmfd, &pte, sizeof(pte), ofs) != sizeof(pte)) {
284 		_kvm_syserr(kd, kd->program, "_amd64_vatop: read");
285 		goto invalid;
286 	}
287 	if ((pte & AMD64_PG_V) == 0) {
288 		_kvm_err(kd, kd->program, "_amd64_vatop: pte not valid");
289 		goto invalid;
290 	}
291 
292 	a = (pte & AMD64_PG_FRAME) + offset;
293 	s = _kvm_pa2off(kd, a, pa);
294 	if (s == 0) {
295 		_kvm_err(kd, kd->program, "_amd64_vatop: address not in dump");
296 		goto invalid;
297 	} else
298 		return (AMD64_PAGE_SIZE - offset);
299 
300 invalid:
301 	_kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
302 	return (0);
303 }
304 
305 static int
306 _amd64_kvatop(kvm_t *kd, kvaddr_t va, off_t *pa)
307 {
308 
309 	if (ISALIVE(kd)) {
310 		_kvm_err(kd, 0, "kvm_kvatop called in live kernel!");
311 		return (0);
312 	}
313 	return (_amd64_vatop(kd, va, pa));
314 }
315 
316 int
317 _amd64_native(kvm_t *kd __unused)
318 {
319 
320 #ifdef __amd64__
321 	return (1);
322 #else
323 	return (0);
324 #endif
325 }
326 
327 static struct kvm_arch kvm_amd64 = {
328 	.ka_probe = _amd64_probe,
329 	.ka_initvtop = _amd64_initvtop,
330 	.ka_freevtop = _amd64_freevtop,
331 	.ka_kvatop = _amd64_kvatop,
332 	.ka_native = _amd64_native,
333 };
334 
335 KVM_ARCH(kvm_amd64);
336