xref: /freebsd/lib/libkvm/kvm_amd64.c (revision fcb560670601b2a4d87bb31d7531c8dcc37ee71b)
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  * 4. 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/user.h>
50 #include <sys/proc.h>
51 #include <sys/stat.h>
52 #include <sys/mman.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <unistd.h>
56 #include <nlist.h>
57 #include <kvm.h>
58 
59 #include <vm/vm.h>
60 #include <vm/vm_param.h>
61 
62 #include <machine/elf.h>
63 
64 #include <limits.h>
65 
66 #include "kvm_private.h"
67 
68 #ifndef btop
69 #define	btop(x)		(amd64_btop(x))
70 #define	ptob(x)		(amd64_ptob(x))
71 #endif
72 
73 /* minidump must be the first item! */
74 struct vmstate {
75 	int		minidump;	/* 1 = minidump mode */
76 	void		*mmapbase;
77 	size_t		mmapsize;
78 	pml4_entry_t	*PML4;
79 };
80 
81 /*
82  * Map the ELF headers into the process' address space. We do this in two
83  * steps: first the ELF header itself and using that information the whole
84  * set of headers.
85  */
86 static int
87 _kvm_maphdrs(kvm_t *kd, size_t sz)
88 {
89 	struct vmstate *vm = kd->vmst;
90 
91 	/* munmap() previous mmap(). */
92 	if (vm->mmapbase != NULL) {
93 		munmap(vm->mmapbase, vm->mmapsize);
94 		vm->mmapbase = NULL;
95 	}
96 
97 	vm->mmapsize = sz;
98 	vm->mmapbase = mmap(NULL, sz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
99 	if (vm->mmapbase == MAP_FAILED) {
100 		_kvm_err(kd, kd->program, "cannot mmap corefile");
101 		return (-1);
102 	}
103 	return (0);
104 }
105 
106 /*
107  * Translate a physical memory address to a file-offset in the crash-dump.
108  */
109 static size_t
110 _kvm_pa2off(kvm_t *kd, uint64_t pa, off_t *ofs)
111 {
112 	Elf_Ehdr *e = kd->vmst->mmapbase;
113 	Elf_Phdr *p;
114 	int n;
115 
116 	if (kd->rawdump) {
117 		*ofs = pa;
118 		return (PAGE_SIZE - ((size_t)pa & PAGE_MASK));
119 	}
120 
121 	p = (Elf_Phdr*)((char*)e + e->e_phoff);
122 	n = e->e_phnum;
123 	while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
124 		p++, n--;
125 	if (n == 0)
126 		return (0);
127 	*ofs = (pa - p->p_paddr) + p->p_offset;
128 	return (PAGE_SIZE - ((size_t)pa & PAGE_MASK));
129 }
130 
131 void
132 _kvm_freevtop(kvm_t *kd)
133 {
134 	struct vmstate *vm = kd->vmst;
135 
136 	if (kd->vmst->minidump)
137 		return (_kvm_minidump_freevtop(kd));
138 	if (vm->mmapbase != NULL)
139 		munmap(vm->mmapbase, vm->mmapsize);
140 	if (vm->PML4)
141 		free(vm->PML4);
142 	free(vm);
143 	kd->vmst = NULL;
144 }
145 
146 int
147 _kvm_initvtop(kvm_t *kd)
148 {
149 	struct nlist nl[2];
150 	u_long pa;
151 	u_long kernbase;
152 	pml4_entry_t	*PML4;
153 	Elf_Ehdr *ehdr;
154 	size_t hdrsz;
155 	char minihdr[8];
156 
157 	if (!kd->rawdump && pread(kd->pmfd, &minihdr, 8, 0) == 8)
158 		if (memcmp(&minihdr, "minidump", 8) == 0)
159 			return (_kvm_minidump_initvtop(kd));
160 
161 	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
162 	if (kd->vmst == 0) {
163 		_kvm_err(kd, kd->program, "cannot allocate vm");
164 		return (-1);
165 	}
166 	kd->vmst->PML4 = 0;
167 
168 	if (kd->rawdump == 0) {
169 		if (_kvm_maphdrs(kd, sizeof(Elf_Ehdr)) == -1)
170 			return (-1);
171 
172 		ehdr = kd->vmst->mmapbase;
173 		hdrsz = ehdr->e_phoff + ehdr->e_phentsize * ehdr->e_phnum;
174 		if (_kvm_maphdrs(kd, hdrsz) == -1)
175 			return (-1);
176 	}
177 
178 	nl[0].n_name = "kernbase";
179 	nl[1].n_name = 0;
180 
181 	if (kvm_nlist(kd, nl) != 0) {
182 		_kvm_err(kd, kd->program, "bad namelist - no kernbase");
183 		return (-1);
184 	}
185 	kernbase = nl[0].n_value;
186 
187 	nl[0].n_name = "KPML4phys";
188 	nl[1].n_name = 0;
189 
190 	if (kvm_nlist(kd, nl) != 0) {
191 		_kvm_err(kd, kd->program, "bad namelist - no KPML4phys");
192 		return (-1);
193 	}
194 	if (kvm_read(kd, (nl[0].n_value - kernbase), &pa, sizeof(pa)) !=
195 	    sizeof(pa)) {
196 		_kvm_err(kd, kd->program, "cannot read KPML4phys");
197 		return (-1);
198 	}
199 	PML4 = _kvm_malloc(kd, PAGE_SIZE);
200 	if (kvm_read(kd, pa, PML4, PAGE_SIZE) != PAGE_SIZE) {
201 		_kvm_err(kd, kd->program, "cannot read KPML4phys");
202 		return (-1);
203 	}
204 	kd->vmst->PML4 = PML4;
205 	return (0);
206 }
207 
208 static int
209 _kvm_vatop(kvm_t *kd, u_long va, off_t *pa)
210 {
211 	struct vmstate *vm;
212 	u_long offset;
213 	u_long pdpe_pa;
214 	u_long pde_pa;
215 	u_long pte_pa;
216 	pml4_entry_t pml4e;
217 	pdp_entry_t pdpe;
218 	pd_entry_t pde;
219 	pt_entry_t pte;
220 	u_long pml4eindex;
221 	u_long pdpeindex;
222 	u_long pdeindex;
223 	u_long pteindex;
224 	u_long a;
225 	off_t ofs;
226 	size_t s;
227 
228 	vm = kd->vmst;
229 	offset = va & (PAGE_SIZE - 1);
230 
231 	/*
232 	 * If we are initializing (kernel page table descriptor pointer
233 	 * not yet set) then return pa == va to avoid infinite recursion.
234 	 */
235 	if (vm->PML4 == 0) {
236 		s = _kvm_pa2off(kd, va, pa);
237 		if (s == 0) {
238 			_kvm_err(kd, kd->program,
239 			    "_kvm_vatop: bootstrap data not in dump");
240 			goto invalid;
241 		} else
242 			return (PAGE_SIZE - offset);
243 	}
244 
245 	pml4eindex = (va >> PML4SHIFT) & (NPML4EPG - 1);
246 	pml4e = vm->PML4[pml4eindex];
247 	if (((u_long)pml4e & PG_V) == 0) {
248 		_kvm_err(kd, kd->program, "_kvm_vatop: pml4e not valid");
249 		goto invalid;
250 	}
251 
252 	pdpeindex = (va >> PDPSHIFT) & (NPDPEPG-1);
253 	pdpe_pa = ((u_long)pml4e & PG_FRAME) +
254 	    (pdpeindex * sizeof(pdp_entry_t));
255 
256 	s = _kvm_pa2off(kd, pdpe_pa, &ofs);
257 	if (s < sizeof pdpe) {
258 		_kvm_err(kd, kd->program, "_kvm_vatop: pdpe_pa not found");
259 		goto invalid;
260 	}
261 	if (lseek(kd->pmfd, ofs, 0) == -1) {
262 		_kvm_syserr(kd, kd->program, "_kvm_vatop: lseek pdpe_pa");
263 		goto invalid;
264 	}
265 	if (read(kd->pmfd, &pdpe, sizeof pdpe) != sizeof pdpe) {
266 		_kvm_syserr(kd, kd->program, "_kvm_vatop: read pdpe");
267 		goto invalid;
268 	}
269 	if (((u_long)pdpe & PG_V) == 0) {
270 		_kvm_err(kd, kd->program, "_kvm_vatop: pdpe not valid");
271 		goto invalid;
272 	}
273 
274 	pdeindex = (va >> PDRSHIFT) & (NPDEPG-1);
275 	pde_pa = ((u_long)pdpe & PG_FRAME) + (pdeindex * sizeof(pd_entry_t));
276 
277 	s = _kvm_pa2off(kd, pde_pa, &ofs);
278 	if (s < sizeof pde) {
279 		_kvm_syserr(kd, kd->program, "_kvm_vatop: pde_pa not found");
280 		goto invalid;
281 	}
282 	if (lseek(kd->pmfd, ofs, 0) == -1) {
283 		_kvm_err(kd, kd->program, "_kvm_vatop: lseek pde_pa");
284 		goto invalid;
285 	}
286 	if (read(kd->pmfd, &pde, sizeof pde) != sizeof pde) {
287 		_kvm_syserr(kd, kd->program, "_kvm_vatop: read pde");
288 		goto invalid;
289 	}
290 	if (((u_long)pde & PG_V) == 0) {
291 		_kvm_err(kd, kd->program, "_kvm_vatop: pde not valid");
292 		goto invalid;
293 	}
294 
295 	if ((u_long)pde & PG_PS) {
296 	      /*
297 	       * No final-level page table; ptd describes one 2MB page.
298 	       */
299 #define	PAGE2M_MASK	(NBPDR - 1)
300 #define	PG_FRAME2M	(~PAGE2M_MASK)
301 		a = ((u_long)pde & PG_FRAME2M) + (va & PAGE2M_MASK);
302 		s = _kvm_pa2off(kd, a, pa);
303 		if (s == 0) {
304 			_kvm_err(kd, kd->program,
305 			    "_kvm_vatop: 2MB page address not in dump");
306 			goto invalid;
307 		} else
308 			return (NBPDR - (va & PAGE2M_MASK));
309 	}
310 
311 	pteindex = (va >> PAGE_SHIFT) & (NPTEPG-1);
312 	pte_pa = ((u_long)pde & PG_FRAME) + (pteindex * sizeof(pt_entry_t));
313 
314 	s = _kvm_pa2off(kd, pte_pa, &ofs);
315 	if (s < sizeof pte) {
316 		_kvm_err(kd, kd->program, "_kvm_vatop: pte_pa not found");
317 		goto invalid;
318 	}
319 	if (lseek(kd->pmfd, ofs, 0) == -1) {
320 		_kvm_syserr(kd, kd->program, "_kvm_vatop: lseek");
321 		goto invalid;
322 	}
323 	if (read(kd->pmfd, &pte, sizeof pte) != sizeof pte) {
324 		_kvm_syserr(kd, kd->program, "_kvm_vatop: read");
325 		goto invalid;
326 	}
327 	if (((u_long)pte & PG_V) == 0) {
328 		_kvm_err(kd, kd->program, "_kvm_vatop: pte not valid");
329 		goto invalid;
330 	}
331 
332 	a = ((u_long)pte & PG_FRAME) + offset;
333 	s = _kvm_pa2off(kd, a, pa);
334 	if (s == 0) {
335 		_kvm_err(kd, kd->program, "_kvm_vatop: address not in dump");
336 		goto invalid;
337 	} else
338 		return (PAGE_SIZE - offset);
339 
340 invalid:
341 	_kvm_err(kd, 0, "invalid address (0x%lx)", va);
342 	return (0);
343 }
344 
345 int
346 _kvm_kvatop(kvm_t *kd, u_long va, off_t *pa)
347 {
348 
349 	if (kd->vmst->minidump)
350 		return (_kvm_minidump_kvatop(kd, va, pa));
351 	if (ISALIVE(kd)) {
352 		_kvm_err(kd, 0, "kvm_kvatop called in live kernel!");
353 		return (0);
354 	}
355 	return (_kvm_vatop(kd, va, pa));
356 }
357