xref: /freebsd/lib/libkvm/kvm_i386.c (revision ca987d4641cdcd7f27e153db17c5bf064934faf5)
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  * i386 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 <vm/vm.h>
55 #include <kvm.h>
56 
57 #ifdef __i386__
58 #include <machine/vmparam.h>		/* For KERNBASE. */
59 #endif
60 
61 #include <limits.h>
62 
63 #include "kvm_private.h"
64 #include "kvm_i386.h"
65 
66 struct vmstate {
67 	void		*PTD;
68 	int		pae;
69 	size_t		phnum;
70 	GElf_Phdr	*phdr;
71 };
72 
73 /*
74  * Translate a physical memory address to a file-offset in the crash-dump.
75  */
76 static size_t
77 _kvm_pa2off(kvm_t *kd, uint64_t pa, off_t *ofs)
78 {
79 	struct vmstate *vm = kd->vmst;
80 	GElf_Phdr *p;
81 	size_t n;
82 
83 	if (kd->rawdump) {
84 		*ofs = pa;
85 		return (I386_PAGE_SIZE - (pa & I386_PAGE_MASK));
86 	}
87 
88 	p = vm->phdr;
89 	n = vm->phnum;
90 	while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
91 		p++, n--;
92 	if (n == 0)
93 		return (0);
94 	*ofs = (pa - p->p_paddr) + p->p_offset;
95 	return (I386_PAGE_SIZE - (pa & I386_PAGE_MASK));
96 }
97 
98 static void
99 _i386_freevtop(kvm_t *kd)
100 {
101 	struct vmstate *vm = kd->vmst;
102 
103 	if (vm->PTD)
104 		free(vm->PTD);
105 	free(vm->phdr);
106 	free(vm);
107 	kd->vmst = NULL;
108 }
109 
110 static int
111 _i386_probe(kvm_t *kd)
112 {
113 
114 	return (_kvm_probe_elf_kernel(kd, ELFCLASS32, EM_386) &&
115 	    !_kvm_is_minidump(kd));
116 }
117 
118 static int
119 _i386_initvtop(kvm_t *kd)
120 {
121 	struct kvm_nlist nl[2];
122 	i386_physaddr_t pa;
123 	kvaddr_t kernbase;
124 	char		*PTD;
125 	int		i;
126 
127 	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(struct vmstate));
128 	if (kd->vmst == NULL) {
129 		_kvm_err(kd, kd->program, "cannot allocate vm");
130 		return (-1);
131 	}
132 	kd->vmst->PTD = 0;
133 
134 	if (kd->rawdump == 0) {
135 		if (_kvm_read_core_phdrs(kd, &kd->vmst->phnum,
136 		    &kd->vmst->phdr) == -1)
137 			return (-1);
138 	}
139 
140 	nl[0].n_name = "kernbase";
141 	nl[1].n_name = 0;
142 
143 	if (kvm_nlist2(kd, nl) != 0) {
144 #ifdef __i386__
145 		kernbase = KERNBASE;	/* for old kernels */
146 #else
147 		_kvm_err(kd, kd->program, "cannot resolve kernbase");
148 		return (-1);
149 #endif
150 	} else
151 		kernbase = nl[0].n_value;
152 
153 	nl[0].n_name = "IdlePDPT";
154 	nl[1].n_name = 0;
155 
156 	if (kvm_nlist2(kd, nl) == 0) {
157 		i386_physaddr_pae_t pa64;
158 
159 		if (kvm_read2(kd, (nl[0].n_value - kernbase), &pa,
160 		    sizeof(pa)) != sizeof(pa)) {
161 			_kvm_err(kd, kd->program, "cannot read IdlePDPT");
162 			return (-1);
163 		}
164 		pa = le32toh(pa);
165 		PTD = _kvm_malloc(kd, 4 * I386_PAGE_SIZE);
166 		if (PTD == NULL) {
167 			_kvm_err(kd, kd->program, "cannot allocate PTD");
168 			return (-1);
169 		}
170 		for (i = 0; i < 4; i++) {
171 			if (kvm_read2(kd, pa + (i * sizeof(pa64)), &pa64,
172 			    sizeof(pa64)) != sizeof(pa64)) {
173 				_kvm_err(kd, kd->program, "Cannot read PDPT");
174 				free(PTD);
175 				return (-1);
176 			}
177 			pa64 = le64toh(pa64);
178 			if (kvm_read2(kd, pa64 & I386_PG_FRAME_PAE,
179 			    PTD + (i * I386_PAGE_SIZE), I386_PAGE_SIZE) !=
180 			    I386_PAGE_SIZE) {
181 				_kvm_err(kd, kd->program, "cannot read PDPT");
182 				free(PTD);
183 				return (-1);
184 			}
185 		}
186 		kd->vmst->PTD = PTD;
187 		kd->vmst->pae = 1;
188 	} else {
189 		nl[0].n_name = "IdlePTD";
190 		nl[1].n_name = 0;
191 
192 		if (kvm_nlist2(kd, nl) != 0) {
193 			_kvm_err(kd, kd->program, "bad namelist");
194 			return (-1);
195 		}
196 		if (kvm_read2(kd, (nl[0].n_value - kernbase), &pa,
197 		    sizeof(pa)) != sizeof(pa)) {
198 			_kvm_err(kd, kd->program, "cannot read IdlePTD");
199 			return (-1);
200 		}
201 		pa = le32toh(pa);
202 		PTD = _kvm_malloc(kd, I386_PAGE_SIZE);
203 		if (PTD == NULL) {
204 			_kvm_err(kd, kd->program, "cannot allocate PTD");
205 			return (-1);
206 		}
207 		if (kvm_read2(kd, pa, PTD, I386_PAGE_SIZE) != I386_PAGE_SIZE) {
208 			_kvm_err(kd, kd->program, "cannot read PTD");
209 			return (-1);
210 		}
211 		kd->vmst->PTD = PTD;
212 		kd->vmst->pae = 0;
213 	}
214 	return (0);
215 }
216 
217 static int
218 _i386_vatop(kvm_t *kd, kvaddr_t va, off_t *pa)
219 {
220 	struct vmstate *vm;
221 	i386_physaddr_t offset;
222 	i386_physaddr_t pte_pa;
223 	i386_pde_t pde;
224 	i386_pte_t pte;
225 	kvaddr_t pdeindex;
226 	kvaddr_t pteindex;
227 	size_t s;
228 	i386_physaddr_t a;
229 	off_t ofs;
230 	i386_pde_t *PTD;
231 
232 	vm = kd->vmst;
233 	PTD = (i386_pde_t *)vm->PTD;
234 	offset = va & I386_PAGE_MASK;
235 
236 	/*
237 	 * If we are initializing (kernel page table descriptor pointer
238 	 * not yet set) then return pa == va to avoid infinite recursion.
239 	 */
240 	if (PTD == NULL) {
241 		s = _kvm_pa2off(kd, va, pa);
242 		if (s == 0) {
243 			_kvm_err(kd, kd->program,
244 			    "_i386_vatop: bootstrap data not in dump");
245 			goto invalid;
246 		} else
247 			return (I386_PAGE_SIZE - offset);
248 	}
249 
250 	pdeindex = va >> I386_PDRSHIFT;
251 	pde = le32toh(PTD[pdeindex]);
252 	if ((pde & I386_PG_V) == 0) {
253 		_kvm_err(kd, kd->program, "_i386_vatop: pde not valid");
254 		goto invalid;
255 	}
256 
257 	if (pde & I386_PG_PS) {
258 		/*
259 		 * No second-level page table; ptd describes one 4MB
260 		 * page.  (We assume that the kernel wouldn't set
261 		 * PG_PS without enabling it cr0).
262 		 */
263 		offset = va & I386_PAGE_PS_MASK;
264 		a = (pde & I386_PG_PS_FRAME) + offset;
265 		s = _kvm_pa2off(kd, a, pa);
266 		if (s == 0) {
267 			_kvm_err(kd, kd->program,
268 			    "_i386_vatop: 4MB page address not in dump");
269 			goto invalid;
270 		}
271 		return (I386_NBPDR - offset);
272 	}
273 
274 	pteindex = (va >> I386_PAGE_SHIFT) & (I386_NPTEPG - 1);
275 	pte_pa = (pde & I386_PG_FRAME) + (pteindex * sizeof(pte));
276 
277 	s = _kvm_pa2off(kd, pte_pa, &ofs);
278 	if (s < sizeof(pte)) {
279 		_kvm_err(kd, kd->program, "_i386_vatop: pte_pa not found");
280 		goto invalid;
281 	}
282 
283 	/* XXX This has to be a physical address read, kvm_read is virtual */
284 	if (pread(kd->pmfd, &pte, sizeof(pte), ofs) != sizeof(pte)) {
285 		_kvm_syserr(kd, kd->program, "_i386_vatop: pread");
286 		goto invalid;
287 	}
288 	pte = le32toh(pte);
289 	if ((pte & I386_PG_V) == 0) {
290 		_kvm_err(kd, kd->program, "_kvm_kvatop: pte not valid");
291 		goto invalid;
292 	}
293 
294 	a = (pte & I386_PG_FRAME) + offset;
295 	s = _kvm_pa2off(kd, a, pa);
296 	if (s == 0) {
297 		_kvm_err(kd, kd->program, "_i386_vatop: address not in dump");
298 		goto invalid;
299 	} else
300 		return (I386_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 _i386_vatop_pae(kvm_t *kd, kvaddr_t va, off_t *pa)
309 {
310 	struct vmstate *vm;
311 	i386_physaddr_pae_t offset;
312 	i386_physaddr_pae_t pte_pa;
313 	i386_pde_pae_t pde;
314 	i386_pte_pae_t pte;
315 	kvaddr_t pdeindex;
316 	kvaddr_t pteindex;
317 	size_t s;
318 	i386_physaddr_pae_t a;
319 	off_t ofs;
320 	i386_pde_pae_t *PTD;
321 
322 	vm = kd->vmst;
323 	PTD = (i386_pde_pae_t *)vm->PTD;
324 	offset = va & I386_PAGE_MASK;
325 
326 	/*
327 	 * If we are initializing (kernel page table descriptor pointer
328 	 * not yet set) then return pa == va to avoid infinite recursion.
329 	 */
330 	if (PTD == NULL) {
331 		s = _kvm_pa2off(kd, va, pa);
332 		if (s == 0) {
333 			_kvm_err(kd, kd->program,
334 			    "_i386_vatop_pae: bootstrap data not in dump");
335 			goto invalid;
336 		} else
337 			return (I386_PAGE_SIZE - offset);
338 	}
339 
340 	pdeindex = va >> I386_PDRSHIFT_PAE;
341 	pde = le64toh(PTD[pdeindex]);
342 	if ((pde & I386_PG_V) == 0) {
343 		_kvm_err(kd, kd->program, "_kvm_kvatop_pae: pde not valid");
344 		goto invalid;
345 	}
346 
347 	if (pde & I386_PG_PS) {
348 		/*
349 		 * No second-level page table; ptd describes one 2MB
350 		 * page.  (We assume that the kernel wouldn't set
351 		 * PG_PS without enabling it cr0).
352 		 */
353 		offset = va & I386_PAGE_PS_MASK_PAE;
354 		a = (pde & I386_PG_PS_FRAME_PAE) + offset;
355 		s = _kvm_pa2off(kd, a, pa);
356 		if (s == 0) {
357 			_kvm_err(kd, kd->program,
358 			    "_i386_vatop: 2MB page address not in dump");
359 			goto invalid;
360 		}
361 		return (I386_NBPDR_PAE - offset);
362 	}
363 
364 	pteindex = (va >> I386_PAGE_SHIFT) & (I386_NPTEPG_PAE - 1);
365 	pte_pa = (pde & I386_PG_FRAME_PAE) + (pteindex * sizeof(pde));
366 
367 	s = _kvm_pa2off(kd, pte_pa, &ofs);
368 	if (s < sizeof(pte)) {
369 		_kvm_err(kd, kd->program, "_i386_vatop_pae: pdpe_pa not found");
370 		goto invalid;
371 	}
372 
373 	/* XXX This has to be a physical address read, kvm_read is virtual */
374 	if (pread(kd->pmfd, &pte, sizeof(pte), ofs) != sizeof(pte)) {
375 		_kvm_syserr(kd, kd->program, "_i386_vatop_pae: read");
376 		goto invalid;
377 	}
378 	pte = le64toh(pte);
379 	if ((pte & I386_PG_V) == 0) {
380 		_kvm_err(kd, kd->program, "_i386_vatop_pae: pte not valid");
381 		goto invalid;
382 	}
383 
384 	a = (pte & I386_PG_FRAME_PAE) + offset;
385 	s = _kvm_pa2off(kd, a, pa);
386 	if (s == 0) {
387 		_kvm_err(kd, kd->program,
388 		    "_i386_vatop_pae: address not in dump");
389 		goto invalid;
390 	} else
391 		return (I386_PAGE_SIZE - offset);
392 
393 invalid:
394 	_kvm_err(kd, 0, "invalid address (0x%jx)", (uintmax_t)va);
395 	return (0);
396 }
397 
398 static int
399 _i386_kvatop(kvm_t *kd, kvaddr_t va, off_t *pa)
400 {
401 
402 	if (ISALIVE(kd)) {
403 		_kvm_err(kd, 0, "vatop called in live kernel!");
404 		return (0);
405 	}
406 	if (kd->vmst->pae)
407 		return (_i386_vatop_pae(kd, va, pa));
408 	else
409 		return (_i386_vatop(kd, va, pa));
410 }
411 
412 int
413 _i386_native(kvm_t *kd __unused)
414 {
415 
416 #ifdef __i386__
417 	return (1);
418 #else
419 	return (0);
420 #endif
421 }
422 
423 static struct kvm_arch kvm_i386 = {
424 	.ka_probe = _i386_probe,
425 	.ka_initvtop = _i386_initvtop,
426 	.ka_freevtop = _i386_freevtop,
427 	.ka_kvatop = _i386_kvatop,
428 	.ka_native = _i386_native,
429 };
430 
431 KVM_ARCH(kvm_i386);
432