xref: /freebsd/lib/libkvm/kvm_i386.c (revision d056fa046c6a91b90cd98165face0e42a33a5173)
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. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *	This product includes software developed by the University of
20  *	California, Berkeley and its contributors.
21  * 4. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  */
37 
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #if defined(LIBC_SCCS) && !defined(lint)
42 #if 0
43 static char sccsid[] = "@(#)kvm_hp300.c	8.1 (Berkeley) 6/4/93";
44 #endif
45 #endif /* LIBC_SCCS and not lint */
46 
47 /*
48  * i386 machine dependent routines for kvm.  Hopefully, the forthcoming
49  * vm code will one day obsolete this module.
50  */
51 
52 #include <sys/param.h>
53 #include <sys/user.h>
54 #include <sys/proc.h>
55 #include <sys/stat.h>
56 #include <sys/mman.h>
57 #include <stdlib.h>
58 #include <unistd.h>
59 #include <nlist.h>
60 #include <kvm.h>
61 
62 #include <vm/vm.h>
63 #include <vm/vm_param.h>
64 
65 #include <machine/elf.h>
66 
67 #include <limits.h>
68 
69 #include "kvm_private.h"
70 
71 #ifndef btop
72 #define	btop(x)		(i386_btop(x))
73 #define	ptob(x)		(i386_ptob(x))
74 #endif
75 
76 #define	PG_FRAME_PAE	(~((uint64_t)PAGE_MASK))
77 #define	PDRSHIFT_PAE	21
78 #define	NPTEPG_PAE	(PAGE_SIZE/sizeof(uint64_t))
79 #define	NBPDR_PAE	(1<<PDRSHIFT_PAE)
80 
81 /* minidump must be the first item! */
82 struct vmstate {
83 	int		minidump;	/* 1 = minidump mode */
84 	void		*mmapbase;
85 	size_t		mmapsize;
86 	void		*PTD;
87 	int		pae;
88 };
89 
90 /*
91  * Map the ELF headers into the process' address space. We do this in two
92  * steps: first the ELF header itself and using that information the whole
93  * set of headers. (Taken from kvm_ia64.c)
94  */
95 static int
96 _kvm_maphdrs(kvm_t *kd, size_t sz)
97 {
98 	struct vmstate *vm = kd->vmst;
99 
100 	/* munmap() previous mmap(). */
101 	if (vm->mmapbase != NULL) {
102 		munmap(vm->mmapbase, vm->mmapsize);
103 		vm->mmapbase = NULL;
104 	}
105 
106 	vm->mmapsize = sz;
107 	vm->mmapbase = mmap(NULL, sz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
108 	if (vm->mmapbase == MAP_FAILED) {
109 		_kvm_err(kd, kd->program, "cannot mmap corefile");
110 		return (-1);
111 	}
112 	return (0);
113 }
114 
115 /*
116  * Translate a physical memory address to a file-offset in the crash-dump.
117  * (Taken from kvm_ia64.c)
118  */
119 static size_t
120 _kvm_pa2off(kvm_t *kd, uint64_t pa, off_t *ofs)
121 {
122 	Elf_Ehdr *e = kd->vmst->mmapbase;
123 	Elf_Phdr *p = (Elf_Phdr*)((char*)e + e->e_phoff);
124 	int n = e->e_phnum;
125 
126 	while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
127 		p++, n--;
128 	if (n == 0)
129 		return (0);
130 	*ofs = (pa - p->p_paddr) + p->p_offset;
131 	return (PAGE_SIZE - ((size_t)pa & PAGE_MASK));
132 }
133 
134 void
135 _kvm_freevtop(kvm_t *kd)
136 {
137 	struct vmstate *vm = kd->vmst;
138 
139 	if (kd->vmst->minidump)
140 		return (_kvm_minidump_freevtop(kd));
141 	if (vm->mmapbase != NULL)
142 		munmap(vm->mmapbase, vm->mmapsize);
143 	if (vm->PTD)
144 		free(vm->PTD);
145 	free(vm);
146 	kd->vmst = NULL;
147 }
148 
149 int
150 _kvm_initvtop(kvm_t *kd)
151 {
152 	struct nlist nlist[2];
153 	u_long pa;
154 	u_long kernbase;
155 	char		*PTD;
156 	Elf_Ehdr	*ehdr;
157 	size_t		hdrsz;
158 	int		i;
159 	char		minihdr[8];
160 
161 	if (pread(kd->pmfd, &minihdr, 8, 0) == 8)
162 		if (memcmp(&minihdr, "minidump", 8) == 0)
163 			return (_kvm_minidump_initvtop(kd));
164 
165 	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
166 	if (kd->vmst == 0) {
167 		_kvm_err(kd, kd->program, "cannot allocate vm");
168 		return (-1);
169 	}
170 	kd->vmst->PTD = 0;
171 
172 	if (_kvm_maphdrs(kd, sizeof(Elf_Ehdr)) == -1)
173 		return (-1);
174 
175 	ehdr = kd->vmst->mmapbase;
176 	hdrsz = ehdr->e_phoff + ehdr->e_phentsize * ehdr->e_phnum;
177 	if (_kvm_maphdrs(kd, hdrsz) == -1)
178 		return (-1);
179 
180 	nlist[0].n_name = "kernbase";
181 	nlist[1].n_name = 0;
182 
183 	if (kvm_nlist(kd, nlist) != 0)
184 		kernbase = KERNBASE;	/* for old kernels */
185 	else
186 		kernbase = nlist[0].n_value;
187 
188 	nlist[0].n_name = "IdlePDPT";
189 	nlist[1].n_name = 0;
190 
191 	if (kvm_nlist(kd, nlist) == 0) {
192 		uint64_t pa64;
193 
194 		if (kvm_read(kd, (nlist[0].n_value - kernbase), &pa,
195 		    sizeof(pa)) != sizeof(pa)) {
196 			_kvm_err(kd, kd->program, "cannot read IdlePDPT");
197 			return (-1);
198 		}
199 		PTD = _kvm_malloc(kd, 4 * PAGE_SIZE);
200 		for (i = 0; i < 4; i++) {
201 			if (kvm_read(kd, pa + (i * sizeof(pa64)), &pa64,
202 			    sizeof(pa64)) != sizeof(pa64)) {
203 				_kvm_err(kd, kd->program, "Cannot read PDPT");
204 				free(PTD);
205 				return (-1);
206 			}
207 			if (kvm_read(kd, pa64 & PG_FRAME_PAE,
208 			    PTD + (i * PAGE_SIZE), PAGE_SIZE) != (PAGE_SIZE)) {
209 				_kvm_err(kd, kd->program, "cannot read PDPT");
210 				free(PTD);
211 				return (-1);
212 			}
213 		}
214 		kd->vmst->PTD = PTD;
215 		kd->vmst->pae = 1;
216 	} else {
217 		nlist[0].n_name = "IdlePTD";
218 		nlist[1].n_name = 0;
219 
220 		if (kvm_nlist(kd, nlist) != 0) {
221 			_kvm_err(kd, kd->program, "bad namelist");
222 			return (-1);
223 		}
224 		if (kvm_read(kd, (nlist[0].n_value - kernbase), &pa,
225 		    sizeof(pa)) != sizeof(pa)) {
226 			_kvm_err(kd, kd->program, "cannot read IdlePTD");
227 			return (-1);
228 		}
229 		PTD = _kvm_malloc(kd, PAGE_SIZE);
230 		if (kvm_read(kd, pa, PTD, PAGE_SIZE) != PAGE_SIZE) {
231 			_kvm_err(kd, kd->program, "cannot read PTD");
232 			return (-1);
233 		}
234 		kd->vmst->PTD = PTD;
235 		return (0);
236 		kd->vmst->pae = 0;
237 	}
238 	return (0);
239 }
240 
241 static int
242 _kvm_vatop(kvm_t *kd, u_long va, off_t *pa)
243 {
244 	struct vmstate *vm;
245 	u_long offset;
246 	u_long pte_pa;
247 	u_long pde_pa;
248 	pd_entry_t pde;
249 	pt_entry_t pte;
250 	u_long pdeindex;
251 	u_long pteindex;
252 	size_t s;
253 	u_long a;
254 	off_t ofs;
255 	uint32_t *PTD;
256 
257 	vm = kd->vmst;
258 	PTD = (uint32_t *)vm->PTD;
259 	offset = va & (PAGE_SIZE - 1);
260 
261 	/*
262 	 * If we are initializing (kernel page table descriptor pointer
263 	 * not yet set) then return pa == va to avoid infinite recursion.
264 	 */
265 	if (PTD == 0) {
266 		s = _kvm_pa2off(kd, va, pa);
267 		if (s == 0) {
268 			_kvm_err(kd, kd->program,
269 			    "_kvm_vatop: bootstrap data not in dump");
270 			goto invalid;
271 		} else
272 			return (PAGE_SIZE - offset);
273 	}
274 
275 	pdeindex = va >> PDRSHIFT;
276 	pde = PTD[pdeindex];
277 	if (((u_long)pde & PG_V) == 0) {
278 		_kvm_err(kd, kd->program, "_kvm_vatop: pde not valid");
279 		goto invalid;
280 	}
281 
282 	if ((u_long)pde & PG_PS) {
283 	      /*
284 	       * No second-level page table; ptd describes one 4MB page.
285 	       * (We assume that the kernel wouldn't set PG_PS without enabling
286 	       * it cr0).
287 	       */
288 #define	PAGE4M_MASK	(NBPDR - 1)
289 #define	PG_FRAME4M	(~PAGE4M_MASK)
290 		pde_pa = ((u_long)pde & PG_FRAME4M) + (va & PAGE4M_MASK);
291 		s = _kvm_pa2off(kd, pde_pa, &ofs);
292 		if (s < sizeof pde) {
293 			_kvm_syserr(kd, kd->program,
294 			    "_kvm_vatop: pde_pa not found");
295 			goto invalid;
296 		}
297 		*pa = ofs;
298 		return (NBPDR - (va & PAGE4M_MASK));
299 	}
300 
301 	pteindex = (va >> PAGE_SHIFT) & (NPTEPG-1);
302 	pte_pa = ((u_long)pde & PG_FRAME) + (pteindex * sizeof(pde));
303 
304 	s = _kvm_pa2off(kd, pte_pa, &ofs);
305 	if (s < sizeof pte) {
306 		_kvm_err(kd, kd->program, "_kvm_vatop: pdpe_pa not found");
307 		goto invalid;
308 	}
309 
310 	/* XXX This has to be a physical address read, kvm_read is virtual */
311 	if (lseek(kd->pmfd, ofs, 0) == -1) {
312 		_kvm_syserr(kd, kd->program, "_kvm_vatop: lseek");
313 		goto invalid;
314 	}
315 	if (read(kd->pmfd, &pte, sizeof pte) != sizeof pte) {
316 		_kvm_syserr(kd, kd->program, "_kvm_vatop: read");
317 		goto invalid;
318 	}
319 	if (((u_long)pte & PG_V) == 0) {
320 		_kvm_err(kd, kd->program, "_kvm_kvatop: pte not valid");
321 		goto invalid;
322 	}
323 
324 	a = ((u_long)pte & PG_FRAME) + offset;
325 	s =_kvm_pa2off(kd, a, pa);
326 	if (s == 0) {
327 		_kvm_err(kd, kd->program, "_kvm_vatop: address not in dump");
328 		goto invalid;
329 	} else
330 		return (PAGE_SIZE - offset);
331 
332 invalid:
333 	_kvm_err(kd, 0, "invalid address (0x%lx)", va);
334 	return (0);
335 }
336 
337 static int
338 _kvm_vatop_pae(kvm_t *kd, u_long va, off_t *pa)
339 {
340 	struct vmstate *vm;
341 	uint64_t offset;
342 	uint64_t pte_pa;
343 	uint64_t pde_pa;
344 	uint64_t pde;
345 	uint64_t pte;
346 	u_long pdeindex;
347 	u_long pteindex;
348 	size_t s;
349 	uint64_t a;
350 	off_t ofs;
351 	uint64_t *PTD;
352 
353 	vm = kd->vmst;
354 	PTD = (uint64_t *)vm->PTD;
355 	offset = va & (PAGE_SIZE - 1);
356 
357 	/*
358 	 * If we are initializing (kernel page table descriptor pointer
359 	 * not yet set) then return pa == va to avoid infinite recursion.
360 	 */
361 	if (PTD == 0) {
362 		s = _kvm_pa2off(kd, va, pa);
363 		if (s == 0) {
364 			_kvm_err(kd, kd->program,
365 			    "_kvm_vatop_pae: bootstrap data not in dump");
366 			goto invalid;
367 		} else
368 			return (PAGE_SIZE - offset);
369 	}
370 
371 	pdeindex = va >> PDRSHIFT_PAE;
372 	pde = PTD[pdeindex];
373 	if (((u_long)pde & PG_V) == 0) {
374 		_kvm_err(kd, kd->program, "_kvm_kvatop_pae: pde not valid");
375 		goto invalid;
376 	}
377 
378 	if ((u_long)pde & PG_PS) {
379 	      /*
380 	       * No second-level page table; ptd describes one 2MB page.
381 	       * (We assume that the kernel wouldn't set PG_PS without enabling
382 	       * it cr0).
383 	       */
384 #define	PAGE2M_MASK	(NBPDR_PAE - 1)
385 #define	PG_FRAME2M	(~PAGE2M_MASK)
386 		pde_pa = ((u_long)pde & PG_FRAME2M) + (va & PAGE2M_MASK);
387 		s = _kvm_pa2off(kd, pde_pa, &ofs);
388 		if (s < sizeof pde) {
389 			_kvm_syserr(kd, kd->program,
390 			    "_kvm_vatop_pae: pde_pa not found");
391 			goto invalid;
392 		}
393 		*pa = ofs;
394 		return (NBPDR_PAE - (va & PAGE2M_MASK));
395 	}
396 
397 	pteindex = (va >> PAGE_SHIFT) & (NPTEPG_PAE-1);
398 	pte_pa = ((uint64_t)pde & PG_FRAME_PAE) + (pteindex * sizeof(pde));
399 
400 	s = _kvm_pa2off(kd, pte_pa, &ofs);
401 	if (s < sizeof pte) {
402 		_kvm_err(kd, kd->program, "_kvm_vatop_pae: pdpe_pa not found");
403 		goto invalid;
404 	}
405 
406 	/* XXX This has to be a physical address read, kvm_read is virtual */
407 	if (lseek(kd->pmfd, ofs, 0) == -1) {
408 		_kvm_syserr(kd, kd->program, "_kvm_vatop_pae: lseek");
409 		goto invalid;
410 	}
411 	if (read(kd->pmfd, &pte, sizeof pte) != sizeof pte) {
412 		_kvm_syserr(kd, kd->program, "_kvm_vatop_pae: read");
413 		goto invalid;
414 	}
415 	if (((uint64_t)pte & PG_V) == 0) {
416 		_kvm_err(kd, kd->program, "_kvm_vatop_pae: pte not valid");
417 		goto invalid;
418 	}
419 
420 	a = ((uint64_t)pte & PG_FRAME_PAE) + offset;
421 	s =_kvm_pa2off(kd, a, pa);
422 	if (s == 0) {
423 		_kvm_err(kd, kd->program,
424 		    "_kvm_vatop_pae: address not in dump");
425 		goto invalid;
426 	} else
427 		return (PAGE_SIZE - offset);
428 
429 invalid:
430 	_kvm_err(kd, 0, "invalid address (0x%lx)", va);
431 	return (0);
432 }
433 
434 int
435 _kvm_kvatop(kvm_t *kd, u_long va, off_t *pa)
436 {
437 
438 	if (kd->vmst->minidump)
439 		return (_kvm_minidump_kvatop(kd, va, pa));
440 	if (ISALIVE(kd)) {
441 		_kvm_err(kd, 0, "vatop called in live kernel!");
442 		return (0);
443 	}
444 	if (kd->vmst->pae)
445 		return (_kvm_vatop_pae(kd, va, pa));
446 	else
447 		return (_kvm_vatop(kd, va, pa));
448 }
449