xref: /freebsd/lib/libkvm/kvm_minidump_amd64.c (revision 4c9a0adad18263ec8725d9bfc5f560c6ad1da8bd)
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  * AMD64 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/amd64/include/minidump.h"
43 
44 #include <limits.h>
45 
46 #include "kvm_private.h"
47 #include "kvm_amd64.h"
48 
49 #define	amd64_round_page(x)	roundup2((kvaddr_t)(x), AMD64_PAGE_SIZE)
50 #define	VM_IS_V1(vm)		(vm->hdr.version == 1)
51 #define	VA_OFF(vm, va)		\
52 	(VM_IS_V1(vm) ? ((va) & (AMD64_PAGE_SIZE - 1)) : ((va) & AMD64_PAGE_MASK))
53 
54 struct vmstate {
55 	struct minidumphdr hdr;
56 };
57 
58 static vm_prot_t
59 _amd64_entry_to_prot(uint64_t entry)
60 {
61 	vm_prot_t prot = VM_PROT_READ;
62 
63 	if ((entry & AMD64_PG_RW) != 0)
64 		prot |= VM_PROT_WRITE;
65 	if ((entry & AMD64_PG_NX) == 0)
66 		prot |= VM_PROT_EXECUTE;
67 	return prot;
68 }
69 
70 /*
71  * Version 2 minidumps use page directory entries, while version 1 use page
72  * table entries.
73  */
74 
75 static amd64_pde_t
76 _amd64_pde_get(kvm_t *kd, u_long pdeindex)
77 {
78 	amd64_pde_t *pde = _kvm_pmap_get(kd, pdeindex, sizeof(*pde));
79 
80 	return le64toh(*pde);
81 }
82 
83 static amd64_pte_t
84 _amd64_pte_get(kvm_t *kd, u_long pteindex)
85 {
86 	amd64_pte_t *pte = _kvm_pmap_get(kd, pteindex, sizeof(*pte));
87 
88 	return le64toh(*pte);
89 }
90 
91 /* Get the first page table entry for a given page directory index. */
92 static amd64_pte_t *
93 _amd64_pde_first_pte(kvm_t *kd, u_long pdeindex)
94 {
95 	u_long *pa;
96 
97 	pa = _kvm_pmap_get(kd, pdeindex, sizeof(amd64_pde_t));
98 	if (pa == NULL)
99 		return NULL;
100 	return _kvm_map_get(kd, *pa & AMD64_PG_FRAME, AMD64_PAGE_SIZE);
101 }
102 
103 static int
104 _amd64_minidump_probe(kvm_t *kd)
105 {
106 
107 	return (_kvm_probe_elf_kernel(kd, ELFCLASS64, EM_X86_64) &&
108 	    _kvm_is_minidump(kd));
109 }
110 
111 static void
112 _amd64_minidump_freevtop(kvm_t *kd)
113 {
114 	struct vmstate *vm = kd->vmst;
115 
116 	free(vm);
117 	kd->vmst = NULL;
118 }
119 
120 static int
121 _amd64_minidump_initvtop(kvm_t *kd)
122 {
123 	struct vmstate *vmst;
124 	off_t off, dump_avail_off, sparse_off;
125 
126 	vmst = _kvm_malloc(kd, sizeof(*vmst));
127 	if (vmst == NULL) {
128 		_kvm_err(kd, kd->program, "cannot allocate vm");
129 		return (-1);
130 	}
131 	kd->vmst = vmst;
132 	if (pread(kd->pmfd, &vmst->hdr, sizeof(vmst->hdr), 0) !=
133 	    sizeof(vmst->hdr)) {
134 		_kvm_err(kd, kd->program, "cannot read dump header");
135 		return (-1);
136 	}
137 	if (strncmp(MINIDUMP_MAGIC, vmst->hdr.magic, sizeof(vmst->hdr.magic)) != 0) {
138 		_kvm_err(kd, kd->program, "not a minidump for this platform");
139 		return (-1);
140 	}
141 
142 	/*
143 	 * NB: amd64 minidump header is binary compatible between version 1
144 	 * and version 2; version 3 adds the dumpavailsize field
145 	 */
146 	vmst->hdr.version = le32toh(vmst->hdr.version);
147 	if (vmst->hdr.version > MINIDUMP_VERSION || vmst->hdr.version < 1) {
148 		_kvm_err(kd, kd->program, "wrong minidump version. expected %d got %d",
149 		    MINIDUMP_VERSION, vmst->hdr.version);
150 		return (-1);
151 	}
152 	vmst->hdr.msgbufsize = le32toh(vmst->hdr.msgbufsize);
153 	vmst->hdr.bitmapsize = le32toh(vmst->hdr.bitmapsize);
154 	vmst->hdr.pmapsize = le32toh(vmst->hdr.pmapsize);
155 	vmst->hdr.kernbase = le64toh(vmst->hdr.kernbase);
156 	vmst->hdr.dmapbase = le64toh(vmst->hdr.dmapbase);
157 	vmst->hdr.dmapend = le64toh(vmst->hdr.dmapend);
158 	vmst->hdr.dumpavailsize = vmst->hdr.version == MINIDUMP_VERSION ?
159 	    le32toh(vmst->hdr.dumpavailsize) : 0;
160 
161 	/* Skip header and msgbuf */
162 	dump_avail_off = AMD64_PAGE_SIZE + amd64_round_page(vmst->hdr.msgbufsize);
163 
164 	/* Skip dump_avail */
165 	off = dump_avail_off + amd64_round_page(vmst->hdr.dumpavailsize);
166 
167 	sparse_off = off + amd64_round_page(vmst->hdr.bitmapsize) +
168 	    amd64_round_page(vmst->hdr.pmapsize);
169 	if (_kvm_pt_init(kd, vmst->hdr.dumpavailsize, dump_avail_off,
170 	    vmst->hdr.bitmapsize, off, sparse_off, AMD64_PAGE_SIZE) == -1) {
171 		return (-1);
172 	}
173 	off += amd64_round_page(vmst->hdr.bitmapsize);
174 
175 	if (_kvm_pmap_init(kd, vmst->hdr.pmapsize, off) == -1) {
176 		return (-1);
177 	}
178 	off += amd64_round_page(vmst->hdr.pmapsize);
179 
180 	return (0);
181 }
182 
183 static int
184 _amd64_minidump_vatop_v1(kvm_t *kd, kvaddr_t va, off_t *pa)
185 {
186 	struct vmstate *vm;
187 	amd64_physaddr_t offset;
188 	amd64_pte_t pte;
189 	kvaddr_t pteindex;
190 	amd64_physaddr_t a;
191 	off_t ofs;
192 
193 	vm = kd->vmst;
194 	offset = va & AMD64_PAGE_MASK;
195 
196 	if (va >= vm->hdr.kernbase) {
197 		pteindex = (va - vm->hdr.kernbase) >> AMD64_PAGE_SHIFT;
198 		if (pteindex >= vm->hdr.pmapsize / sizeof(pte))
199 			goto invalid;
200 		pte = _amd64_pte_get(kd, pteindex);
201 		if ((pte & AMD64_PG_V) == 0) {
202 			_kvm_err(kd, kd->program,
203 			    "_amd64_minidump_vatop_v1: pte not valid");
204 			goto invalid;
205 		}
206 		a = pte & AMD64_PG_FRAME;
207 		ofs = _kvm_pt_find(kd, a, AMD64_PAGE_SIZE);
208 		if (ofs == -1) {
209 			_kvm_err(kd, kd->program,
210 	    "_amd64_minidump_vatop_v1: physical address 0x%jx not in minidump",
211 			    (uintmax_t)a);
212 			goto invalid;
213 		}
214 		*pa = ofs + offset;
215 		return (AMD64_PAGE_SIZE - offset);
216 	} else if (va >= vm->hdr.dmapbase && va < vm->hdr.dmapend) {
217 		a = (va - vm->hdr.dmapbase) & ~AMD64_PAGE_MASK;
218 		ofs = _kvm_pt_find(kd, a, AMD64_PAGE_SIZE);
219 		if (ofs == -1) {
220 			_kvm_err(kd, kd->program,
221     "_amd64_minidump_vatop_v1: direct map address 0x%jx not in minidump",
222 			    (uintmax_t)va);
223 			goto invalid;
224 		}
225 		*pa = ofs + offset;
226 		return (AMD64_PAGE_SIZE - offset);
227 	} else {
228 		_kvm_err(kd, kd->program,
229 	    "_amd64_minidump_vatop_v1: virtual address 0x%jx not minidumped",
230 		    (uintmax_t)va);
231 		goto invalid;
232 	}
233 
234 invalid:
235 	_kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
236 	return (0);
237 }
238 
239 static int
240 _amd64_minidump_vatop(kvm_t *kd, kvaddr_t va, off_t *pa)
241 {
242 	amd64_pte_t pt[AMD64_NPTEPG];
243 	struct vmstate *vm;
244 	amd64_physaddr_t offset;
245 	amd64_pde_t pde;
246 	amd64_pte_t pte;
247 	kvaddr_t pteindex;
248 	kvaddr_t pdeindex;
249 	amd64_physaddr_t a;
250 	off_t ofs;
251 
252 	vm = kd->vmst;
253 	offset = va & AMD64_PAGE_MASK;
254 
255 	if (va >= vm->hdr.kernbase) {
256 		pdeindex = (va - vm->hdr.kernbase) >> AMD64_PDRSHIFT;
257 		if (pdeindex >= vm->hdr.pmapsize / sizeof(pde))
258 			goto invalid;
259 		pde = _amd64_pde_get(kd, pdeindex);
260 		if ((pde & AMD64_PG_V) == 0) {
261 			_kvm_err(kd, kd->program,
262 			    "_amd64_minidump_vatop: pde not valid");
263 			goto invalid;
264 		}
265 		if ((pde & AMD64_PG_PS) == 0) {
266 			a = pde & AMD64_PG_FRAME;
267 			/* TODO: Just read the single PTE */
268 			ofs = _kvm_pt_find(kd, a, AMD64_PAGE_SIZE);
269 			if (ofs == -1) {
270 				_kvm_err(kd, kd->program,
271 				    "cannot find page table entry for %ju",
272 				    (uintmax_t)a);
273 				goto invalid;
274 			}
275 			if (pread(kd->pmfd, &pt, AMD64_PAGE_SIZE, ofs) !=
276 			    AMD64_PAGE_SIZE) {
277 				_kvm_err(kd, kd->program,
278 				    "cannot read page table entry for %ju",
279 				    (uintmax_t)a);
280 				goto invalid;
281 			}
282 			pteindex = (va >> AMD64_PAGE_SHIFT) &
283 			    (AMD64_NPTEPG - 1);
284 			pte = le64toh(pt[pteindex]);
285 			if ((pte & AMD64_PG_V) == 0) {
286 				_kvm_err(kd, kd->program,
287 				    "_amd64_minidump_vatop: pte not valid");
288 				goto invalid;
289 			}
290 			a = pte & AMD64_PG_FRAME;
291 		} else {
292 			a = pde & AMD64_PG_PS_FRAME;
293 			a += (va & AMD64_PDRMASK) ^ offset;
294 		}
295 		ofs = _kvm_pt_find(kd, a, AMD64_PAGE_SIZE);
296 		if (ofs == -1) {
297 			_kvm_err(kd, kd->program,
298 	    "_amd64_minidump_vatop: physical address 0x%jx not in minidump",
299 			    (uintmax_t)a);
300 			goto invalid;
301 		}
302 		*pa = ofs + offset;
303 		return (AMD64_PAGE_SIZE - offset);
304 	} else if (va >= vm->hdr.dmapbase && va < vm->hdr.dmapend) {
305 		a = (va - vm->hdr.dmapbase) & ~AMD64_PAGE_MASK;
306 		ofs = _kvm_pt_find(kd, a, AMD64_PAGE_SIZE);
307 		if (ofs == -1) {
308 			_kvm_err(kd, kd->program,
309 	    "_amd64_minidump_vatop: direct map address 0x%jx not in minidump",
310 			    (uintmax_t)va);
311 			goto invalid;
312 		}
313 		*pa = ofs + offset;
314 		return (AMD64_PAGE_SIZE - offset);
315 	} else {
316 		_kvm_err(kd, kd->program,
317 	    "_amd64_minidump_vatop: virtual address 0x%jx not minidumped",
318 		    (uintmax_t)va);
319 		goto invalid;
320 	}
321 
322 invalid:
323 	_kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
324 	return (0);
325 }
326 
327 static int
328 _amd64_minidump_kvatop(kvm_t *kd, kvaddr_t va, off_t *pa)
329 {
330 
331 	if (ISALIVE(kd)) {
332 		_kvm_err(kd, 0,
333 		    "_amd64_minidump_kvatop called in live kernel!");
334 		return (0);
335 	}
336 	if (((struct vmstate *)kd->vmst)->hdr.version == 1)
337 		return (_amd64_minidump_vatop_v1(kd, va, pa));
338 	else
339 		return (_amd64_minidump_vatop(kd, va, pa));
340 }
341 
342 static int
343 _amd64_minidump_walk_pages(kvm_t *kd, kvm_walk_pages_cb_t *cb, void *arg)
344 {
345 	struct vmstate *vm = kd->vmst;
346 	u_long npdes = vm->hdr.pmapsize / sizeof(amd64_pde_t);
347 	u_long bmindex, dva, pa, pdeindex, va;
348 	struct kvm_bitmap bm;
349 	int ret = 0;
350 	vm_prot_t prot;
351 	unsigned int pgsz = AMD64_PAGE_SIZE;
352 
353 	if (vm->hdr.version < 2)
354 		return (0);
355 
356 	if (!_kvm_bitmap_init(&bm, vm->hdr.bitmapsize, &bmindex))
357 		return (0);
358 
359 	for (pdeindex = 0; pdeindex < npdes; pdeindex++) {
360 		amd64_pde_t pde = _amd64_pde_get(kd, pdeindex);
361 		amd64_pte_t *ptes;
362 		u_long i;
363 
364 		va = vm->hdr.kernbase + (pdeindex << AMD64_PDRSHIFT);
365 		if ((pde & AMD64_PG_V) == 0)
366 			continue;
367 
368 		if ((pde & AMD64_PG_PS) != 0) {
369 			/*
370 			 * Large page.  Iterate on each 4K page section
371 			 * within this page.  This differs from 4K pages in
372 			 * that every page here uses the same PDE to
373 			 * generate permissions.
374 			 */
375 			pa = (pde & AMD64_PG_PS_FRAME) +
376 			    ((va & AMD64_PDRMASK) ^ VA_OFF(vm, va));
377 			dva = vm->hdr.dmapbase + pa;
378 			_kvm_bitmap_set(&bm, _kvm_pa_bit_id(kd, pa, AMD64_PAGE_SIZE));
379 			if (!_kvm_visit_cb(kd, cb, arg, pa, va, dva,
380 			    _amd64_entry_to_prot(pde), AMD64_NBPDR, pgsz)) {
381 				goto out;
382 			}
383 			continue;
384 		}
385 
386 		/* 4K pages: pde references another page of entries. */
387 		ptes = _amd64_pde_first_pte(kd, pdeindex);
388 		/* Ignore page directory pages that were not dumped. */
389 		if (ptes == NULL)
390 			continue;
391 
392 		for (i = 0; i < AMD64_NPTEPG; i++) {
393 			amd64_pte_t pte = (u_long)ptes[i];
394 
395 			pa = pte & AMD64_PG_FRAME;
396 			dva = vm->hdr.dmapbase + pa;
397 			if ((pte & AMD64_PG_V) != 0) {
398 				_kvm_bitmap_set(&bm,
399 				    _kvm_pa_bit_id(kd, pa, AMD64_PAGE_SIZE));
400 				if (!_kvm_visit_cb(kd, cb, arg, pa, va, dva,
401 				    _amd64_entry_to_prot(pte), pgsz, 0)) {
402 					goto out;
403 				}
404 			}
405 			va += AMD64_PAGE_SIZE;
406 		}
407 	}
408 
409 	while (_kvm_bitmap_next(&bm, &bmindex)) {
410 		pa = _kvm_bit_id_pa(kd, bmindex, AMD64_PAGE_SIZE);
411 		if (pa == _KVM_PA_INVALID)
412 			break;
413 		dva = vm->hdr.dmapbase + pa;
414 		if (vm->hdr.dmapend < (dva + pgsz))
415 			break;
416 		va = 0;
417 		/* amd64/pmap.c: create_pagetables(): dmap always R|W. */
418 		prot = VM_PROT_READ | VM_PROT_WRITE;
419 		if (!_kvm_visit_cb(kd, cb, arg, pa, va, dva, prot, pgsz, 0)) {
420 			goto out;
421 		}
422 	}
423 
424 	ret = 1;
425 
426 out:
427 	_kvm_bitmap_deinit(&bm);
428 	return (ret);
429 }
430 
431 static struct kvm_arch kvm_amd64_minidump = {
432 	.ka_probe = _amd64_minidump_probe,
433 	.ka_initvtop = _amd64_minidump_initvtop,
434 	.ka_freevtop = _amd64_minidump_freevtop,
435 	.ka_kvatop = _amd64_minidump_kvatop,
436 	.ka_native = _amd64_native,
437 	.ka_walk_pages = _amd64_minidump_walk_pages,
438 };
439 
440 KVM_ARCH(kvm_amd64_minidump);
441