xref: /freebsd/lib/libkvm/kvm_amd64.c (revision cbd30a72ca196976c1c700400ecd424baa1b9c16)
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  * 3. 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("$FreeBSD$");
36 
37 #if defined(LIBC_SCCS) && !defined(lint)
38 #if 0
39 static 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 
61 struct 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  */
70 static 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 
92 static 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 
104 static 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 
112 static 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 
169 static 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 
302 invalid:
303 	_kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
304 	return (0);
305 }
306 
307 static 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 
318 int
319 _amd64_native(kvm_t *kd)
320 {
321 
322 #ifdef __amd64__
323 	return (1);
324 #else
325 	return (0);
326 #endif
327 }
328 
329 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 
337 KVM_ARCH(kvm_amd64);
338