xref: /freebsd/lib/libkvm/kvm_minidump_i386.c (revision 7fdf597e96a02165cfe22ff357b857d5fa15ed8a)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2006 Peter Wemm
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/cdefs.h>
29 /*
30  * i386 machine dependent routines for kvm and minidumps.
31  */
32 
33 #include <sys/param.h>
34 #include <sys/endian.h>
35 #include <stdint.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <unistd.h>
39 #include <vm/vm.h>
40 #include <kvm.h>
41 
42 #include "../../sys/i386/include/minidump.h"
43 
44 #include <limits.h>
45 
46 #include "kvm_private.h"
47 #include "kvm_i386.h"
48 
49 #define	i386_round_page(x)	roundup2((kvaddr_t)(x), I386_PAGE_SIZE)
50 
51 struct vmstate {
52 	struct minidumphdr hdr;
53 };
54 
55 static i386_pte_pae_t
56 _i386_pte_pae_get(kvm_t *kd, u_long pteindex)
57 {
58 	i386_pte_pae_t *pte = _kvm_pmap_get(kd, pteindex, sizeof(*pte));
59 
60 	return le64toh(*pte);
61 }
62 
63 static i386_pte_t
64 _i386_pte_get(kvm_t *kd, u_long pteindex)
65 {
66 	i386_pte_t *pte = _kvm_pmap_get(kd, pteindex, sizeof(*pte));
67 
68 	return le32toh(*pte);
69 }
70 
71 static int
72 _i386_minidump_probe(kvm_t *kd)
73 {
74 
75 	return (_kvm_probe_elf_kernel(kd, ELFCLASS32, EM_386) &&
76 	    _kvm_is_minidump(kd));
77 }
78 
79 static void
80 _i386_minidump_freevtop(kvm_t *kd)
81 {
82 	struct vmstate *vm = kd->vmst;
83 
84 	free(vm);
85 	kd->vmst = NULL;
86 }
87 
88 static int
89 _i386_minidump_initvtop(kvm_t *kd)
90 {
91 	struct vmstate *vmst;
92 	off_t off, dump_avail_off, sparse_off;
93 
94 	vmst = _kvm_malloc(kd, sizeof(*vmst));
95 	if (vmst == NULL) {
96 		_kvm_err(kd, kd->program, "cannot allocate vm");
97 		return (-1);
98 	}
99 	kd->vmst = vmst;
100 	if (pread(kd->pmfd, &vmst->hdr, sizeof(vmst->hdr), 0) !=
101 	    sizeof(vmst->hdr)) {
102 		_kvm_err(kd, kd->program, "cannot read dump header");
103 		return (-1);
104 	}
105 	if (strncmp(MINIDUMP_MAGIC, vmst->hdr.magic, sizeof(vmst->hdr.magic)) != 0) {
106 		_kvm_err(kd, kd->program, "not a minidump for this platform");
107 		return (-1);
108 	}
109 	vmst->hdr.version = le32toh(vmst->hdr.version);
110 	if (vmst->hdr.version != MINIDUMP_VERSION && vmst->hdr.version != 1) {
111 		_kvm_err(kd, kd->program, "wrong minidump version. expected %d got %d",
112 		    MINIDUMP_VERSION, vmst->hdr.version);
113 		return (-1);
114 	}
115 	vmst->hdr.msgbufsize = le32toh(vmst->hdr.msgbufsize);
116 	vmst->hdr.bitmapsize = le32toh(vmst->hdr.bitmapsize);
117 	vmst->hdr.ptesize = le32toh(vmst->hdr.ptesize);
118 	vmst->hdr.kernbase = le32toh(vmst->hdr.kernbase);
119 	vmst->hdr.paemode = le32toh(vmst->hdr.paemode);
120 	vmst->hdr.dumpavailsize = vmst->hdr.version == MINIDUMP_VERSION ?
121 	    le32toh(vmst->hdr.dumpavailsize) : 0;
122 
123 	/* Skip header and msgbuf */
124 	dump_avail_off = I386_PAGE_SIZE + i386_round_page(vmst->hdr.msgbufsize);
125 
126 	/* Skip dump_avail */
127 	off = dump_avail_off + i386_round_page(vmst->hdr.dumpavailsize);
128 
129 	sparse_off = off + i386_round_page(vmst->hdr.bitmapsize) +
130 	    i386_round_page(vmst->hdr.ptesize);
131 	if (_kvm_pt_init(kd, vmst->hdr.dumpavailsize, dump_avail_off,
132 	    vmst->hdr.bitmapsize, off, sparse_off, I386_PAGE_SIZE) == -1) {
133 		return (-1);
134 	}
135 	off += i386_round_page(vmst->hdr.bitmapsize);
136 
137 	if (_kvm_pmap_init(kd, vmst->hdr.ptesize, off) == -1) {
138 		return (-1);
139 	}
140 	off += i386_round_page(vmst->hdr.ptesize);
141 
142 	return (0);
143 }
144 
145 static int
146 _i386_minidump_vatop_pae(kvm_t *kd, kvaddr_t va, off_t *pa)
147 {
148 	struct vmstate *vm;
149 	i386_physaddr_pae_t offset;
150 	i386_pte_pae_t pte;
151 	kvaddr_t pteindex;
152 	i386_physaddr_pae_t a;
153 	off_t ofs;
154 
155 	vm = kd->vmst;
156 	offset = va & I386_PAGE_MASK;
157 
158 	if (va >= vm->hdr.kernbase) {
159 		pteindex = (va - vm->hdr.kernbase) >> I386_PAGE_SHIFT;
160 		if (pteindex >= vm->hdr.ptesize / sizeof(pte))
161 			goto invalid;
162 		pte = _i386_pte_pae_get(kd, pteindex);
163 		if ((pte & I386_PG_V) == 0) {
164 			_kvm_err(kd, kd->program,
165 			    "_i386_minidump_vatop_pae: pte not valid");
166 			goto invalid;
167 		}
168 		a = pte & I386_PG_FRAME_PAE;
169 		ofs = _kvm_pt_find(kd, a, I386_PAGE_SIZE);
170 		if (ofs == -1) {
171 			_kvm_err(kd, kd->program,
172 	    "_i386_minidump_vatop_pae: physical address 0x%jx not in minidump",
173 			    (uintmax_t)a);
174 			goto invalid;
175 		}
176 		*pa = ofs + offset;
177 		return (I386_PAGE_SIZE - offset);
178 	} else {
179 		_kvm_err(kd, kd->program,
180 	    "_i386_minidump_vatop_pae: virtual address 0x%jx not minidumped",
181 		    (uintmax_t)va);
182 		goto invalid;
183 	}
184 
185 invalid:
186 	_kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
187 	return (0);
188 }
189 
190 static int
191 _i386_minidump_vatop(kvm_t *kd, kvaddr_t va, off_t *pa)
192 {
193 	struct vmstate *vm;
194 	i386_physaddr_t offset;
195 	i386_pte_t pte;
196 	kvaddr_t pteindex;
197 	i386_physaddr_t a;
198 	off_t ofs;
199 
200 	vm = kd->vmst;
201 	offset = va & I386_PAGE_MASK;
202 
203 	if (va >= vm->hdr.kernbase) {
204 		pteindex = (va - vm->hdr.kernbase) >> I386_PAGE_SHIFT;
205 		if (pteindex >= vm->hdr.ptesize / sizeof(pte))
206 			goto invalid;
207 		pte = _i386_pte_get(kd, pteindex);
208 		if ((pte & I386_PG_V) == 0) {
209 			_kvm_err(kd, kd->program,
210 			    "_i386_minidump_vatop: pte not valid");
211 			goto invalid;
212 		}
213 		a = pte & I386_PG_FRAME;
214 		ofs = _kvm_pt_find(kd, a, I386_PAGE_SIZE);
215 		if (ofs == -1) {
216 			_kvm_err(kd, kd->program,
217 	    "_i386_minidump_vatop: physical address 0x%jx not in minidump",
218 			    (uintmax_t)a);
219 			goto invalid;
220 		}
221 		*pa = ofs + offset;
222 		return (I386_PAGE_SIZE - offset);
223 	} else {
224 		_kvm_err(kd, kd->program,
225 	    "_i386_minidump_vatop: virtual address 0x%jx not minidumped",
226 		    (uintmax_t)va);
227 		goto invalid;
228 	}
229 
230 invalid:
231 	_kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
232 	return (0);
233 }
234 
235 static int
236 _i386_minidump_kvatop(kvm_t *kd, kvaddr_t va, off_t *pa)
237 {
238 
239 	if (ISALIVE(kd)) {
240 		_kvm_err(kd, 0, "_i386_minidump_kvatop called in live kernel!");
241 		return (0);
242 	}
243 	if (kd->vmst->hdr.paemode)
244 		return (_i386_minidump_vatop_pae(kd, va, pa));
245 	else
246 		return (_i386_minidump_vatop(kd, va, pa));
247 }
248 
249 static vm_prot_t
250 _i386_entry_to_prot(uint64_t pte)
251 {
252 	vm_prot_t prot = VM_PROT_READ;
253 
254 	/* Source: i386/pmap.c:pmap_protect() */
255 	if (pte & I386_PG_RW)
256 		prot |= VM_PROT_WRITE;
257 	if ((pte & I386_PG_NX) == 0)
258 		prot |= VM_PROT_EXECUTE;
259 
260 	return prot;
261 }
262 
263 struct i386_iter {
264 	kvm_t *kd;
265 	u_long nptes;
266 	u_long pteindex;
267 };
268 
269 static void
270 _i386_iterator_init(struct i386_iter *it, kvm_t *kd)
271 {
272 	struct vmstate *vm = kd->vmst;
273 
274 	it->kd = kd;
275 	it->pteindex = 0;
276 	if (vm->hdr.paemode) {
277 		it->nptes = vm->hdr.ptesize / sizeof(i386_pte_pae_t);
278 	} else {
279 		it->nptes = vm->hdr.ptesize / sizeof(i386_pte_t);
280 	}
281 	return;
282 }
283 
284 static int
285 _i386_iterator_next(struct i386_iter *it, u_long *pa, u_long *va, u_long *dva,
286     vm_prot_t *prot)
287 {
288 	struct vmstate *vm = it->kd->vmst;
289 	i386_pte_t pte32;
290 	i386_pte_pae_t pte64;
291 	int found = 0;
292 
293 	*dva = 0;
294 	*pa = 0;
295 	*va = 0;
296 	*dva = 0;
297 	*prot = 0;
298 	for (; it->pteindex < it->nptes && found == 0; it->pteindex++) {
299 		if (vm->hdr.paemode) {
300 			pte64 = _i386_pte_pae_get(it->kd, it->pteindex);
301 			if ((pte64 & I386_PG_V) == 0)
302 				continue;
303 			*prot = _i386_entry_to_prot(pte64);
304 			*pa = pte64 & I386_PG_FRAME_PAE;
305 		} else {
306 			pte32 = _i386_pte_get(it->kd, it->pteindex);
307 			if ((pte32 & I386_PG_V) == 0)
308 				continue;
309 			*prot = _i386_entry_to_prot(pte32);
310 			*pa = pte32 & I386_PG_FRAME;
311 		}
312 		*va = vm->hdr.kernbase + (it->pteindex << I386_PAGE_SHIFT);
313 		found = 1;
314 	}
315 	return found;
316 }
317 
318 static int
319 _i386_minidump_walk_pages(kvm_t *kd, kvm_walk_pages_cb_t *cb, void *arg)
320 {
321 	struct i386_iter it;
322 	u_long dva, pa, va;
323 	vm_prot_t prot;
324 
325 	_i386_iterator_init(&it, kd);
326 	while (_i386_iterator_next(&it, &pa, &va, &dva, &prot)) {
327 		if (!_kvm_visit_cb(kd, cb, arg, pa, va, dva,
328 		    prot, I386_PAGE_SIZE, 0)) {
329 			return (0);
330 		}
331 	}
332 	return (1);
333 }
334 
335 static struct kvm_arch kvm_i386_minidump = {
336 	.ka_probe = _i386_minidump_probe,
337 	.ka_initvtop = _i386_minidump_initvtop,
338 	.ka_freevtop = _i386_minidump_freevtop,
339 	.ka_kvatop = _i386_minidump_kvatop,
340 	.ka_native = _i386_native,
341 	.ka_walk_pages = _i386_minidump_walk_pages,
342 };
343 
344 KVM_ARCH(kvm_i386_minidump);
345