xref: /freebsd/lib/libkvm/kvm_amd64.c (revision f0a75d274af375d15b97b830966b99a02b7db911)
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 <unistd.h>
55 #include <nlist.h>
56 #include <kvm.h>
57 
58 #include <vm/vm.h>
59 #include <vm/vm_param.h>
60 
61 #include <machine/elf.h>
62 
63 #include <limits.h>
64 
65 #include "kvm_private.h"
66 
67 #ifndef btop
68 #define	btop(x)		(amd64_btop(x))
69 #define	ptob(x)		(amd64_ptob(x))
70 #endif
71 
72 /* minidump must be the first item! */
73 struct vmstate {
74 	int		minidump;	/* 1 = minidump mode */
75 	void		*mmapbase;
76 	size_t		mmapsize;
77 	pml4_entry_t	*PML4;
78 };
79 
80 /*
81  * Map the ELF headers into the process' address space. We do this in two
82  * steps: first the ELF header itself and using that information the whole
83  * set of headers. (Taken from kvm_ia64.c)
84  */
85 static int
86 _kvm_maphdrs(kvm_t *kd, size_t sz)
87 {
88 	struct vmstate *vm = kd->vmst;
89 
90 	/* munmap() previous mmap(). */
91 	if (vm->mmapbase != NULL) {
92 		munmap(vm->mmapbase, vm->mmapsize);
93 		vm->mmapbase = NULL;
94 	}
95 
96 	vm->mmapsize = sz;
97 	vm->mmapbase = mmap(NULL, sz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
98 	if (vm->mmapbase == MAP_FAILED) {
99 		_kvm_err(kd, kd->program, "cannot mmap corefile");
100 		return (-1);
101 	}
102 	return (0);
103 }
104 
105 /*
106  * Translate a physical memory address to a file-offset in the crash-dump.
107  * (Taken from kvm_ia64.c)
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 = (Elf_Phdr*)((char*)e + e->e_phoff);
114 	int n = e->e_phnum;
115 
116 	while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
117 		p++, n--;
118 	if (n == 0)
119 		return (0);
120 	*ofs = (pa - p->p_paddr) + p->p_offset;
121 	return (PAGE_SIZE - ((size_t)pa & PAGE_MASK));
122 }
123 
124 void
125 _kvm_freevtop(kvm_t *kd)
126 {
127 	struct vmstate *vm = kd->vmst;
128 
129 	if (kd->vmst->minidump)
130 		return (_kvm_minidump_freevtop(kd));
131 	if (vm->mmapbase != NULL)
132 		munmap(vm->mmapbase, vm->mmapsize);
133 	if (vm->PML4)
134 		free(vm->PML4);
135 	free(vm);
136 	kd->vmst = NULL;
137 }
138 
139 int
140 _kvm_initvtop(kvm_t *kd)
141 {
142 	struct nlist nlist[2];
143 	u_long pa;
144 	u_long kernbase;
145 	pml4_entry_t	*PML4;
146 	Elf_Ehdr *ehdr;
147 	size_t hdrsz;
148 	char minihdr[8];
149 
150 	if (pread(kd->pmfd, &minihdr, 8, 0) == 8)
151 		if (memcmp(&minihdr, "minidump", 8) == 0)
152 			return (_kvm_minidump_initvtop(kd));
153 
154 	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
155 	if (kd->vmst == 0) {
156 		_kvm_err(kd, kd->program, "cannot allocate vm");
157 		return (-1);
158 	}
159 	kd->vmst->PML4 = 0;
160 
161 	if (_kvm_maphdrs(kd, sizeof(Elf_Ehdr)) == -1)
162 		return (-1);
163 
164 	ehdr = kd->vmst->mmapbase;
165 	hdrsz = ehdr->e_phoff + ehdr->e_phentsize * ehdr->e_phnum;
166 	if (_kvm_maphdrs(kd, hdrsz) == -1)
167 		return (-1);
168 
169 	nlist[0].n_name = "kernbase";
170 	nlist[1].n_name = 0;
171 
172 	if (kvm_nlist(kd, nlist) != 0) {
173 		_kvm_err(kd, kd->program, "bad namelist - no kernbase");
174 		return (-1);
175 	}
176 	kernbase = nlist[0].n_value;
177 
178 	nlist[0].n_name = "KPML4phys";
179 	nlist[1].n_name = 0;
180 
181 	if (kvm_nlist(kd, nlist) != 0) {
182 		_kvm_err(kd, kd->program, "bad namelist - no KPML4phys");
183 		return (-1);
184 	}
185 	if (kvm_read(kd, (nlist[0].n_value - kernbase), &pa, sizeof(pa)) !=
186 	    sizeof(pa)) {
187 		_kvm_err(kd, kd->program, "cannot read KPML4phys");
188 		return (-1);
189 	}
190 	PML4 = _kvm_malloc(kd, PAGE_SIZE);
191 	if (kvm_read(kd, pa, PML4, PAGE_SIZE) != PAGE_SIZE) {
192 		_kvm_err(kd, kd->program, "cannot read KPML4phys");
193 		return (-1);
194 	}
195 	kd->vmst->PML4 = PML4;
196 	return (0);
197 }
198 
199 static int
200 _kvm_vatop(kvm_t *kd, u_long va, off_t *pa)
201 {
202 	struct vmstate *vm;
203 	u_long offset;
204 	u_long pdpe_pa;
205 	u_long pde_pa;
206 	u_long pte_pa;
207 	pml4_entry_t pml4e;
208 	pdp_entry_t pdpe;
209 	pd_entry_t pde;
210 	pt_entry_t pte;
211 	u_long pml4eindex;
212 	u_long pdpeindex;
213 	u_long pdeindex;
214 	u_long pteindex;
215 	int i;
216 	u_long a;
217 	off_t ofs;
218 	size_t s;
219 
220 	vm = kd->vmst;
221 	offset = va & (PAGE_SIZE - 1);
222 
223 	/*
224 	 * If we are initializing (kernel page table descriptor pointer
225 	 * not yet set) then return pa == va to avoid infinite recursion.
226 	 */
227 	if (vm->PML4 == 0) {
228 		s = _kvm_pa2off(kd, va, pa);
229 		if (s == 0) {
230 			_kvm_err(kd, kd->program,
231 			    "_kvm_vatop: bootstrap data not in dump");
232 			goto invalid;
233 		} else
234 			return (PAGE_SIZE - offset);
235 	}
236 
237 	pml4eindex = (va >> PML4SHIFT) & (NPML4EPG - 1);
238 	pml4e = vm->PML4[pml4eindex];
239 	if (((u_long)pml4e & PG_V) == 0) {
240 		_kvm_err(kd, kd->program, "_kvm_vatop: pml4e not valid");
241 		goto invalid;
242 	}
243 
244 	pdpeindex = (va >> PDPSHIFT) & (NPDPEPG-1);
245 	pdpe_pa = ((u_long)pml4e & PG_FRAME) +
246 	    (pdpeindex * sizeof(pdp_entry_t));
247 
248 	s = _kvm_pa2off(kd, pdpe_pa, &ofs);
249 	if (s < sizeof pdpe) {
250 		_kvm_err(kd, kd->program, "_kvm_vatop: pdpe_pa not found");
251 		goto invalid;
252 	}
253 	if (lseek(kd->pmfd, ofs, 0) == -1) {
254 		_kvm_syserr(kd, kd->program, "_kvm_vatop: lseek pdpe_pa");
255 		goto invalid;
256 	}
257 	if (read(kd->pmfd, &pdpe, sizeof pdpe) != sizeof pdpe) {
258 		_kvm_syserr(kd, kd->program, "_kvm_vatop: read pdpe");
259 		goto invalid;
260 	}
261 	if (((u_long)pdpe & PG_V) == 0) {
262 		_kvm_err(kd, kd->program, "_kvm_vatop: pdpe not valid");
263 		goto invalid;
264 	}
265 
266 	pdeindex = (va >> PDRSHIFT) & (NPDEPG-1);
267 	pde_pa = ((u_long)pdpe & PG_FRAME) + (pdeindex * sizeof(pd_entry_t));
268 
269 	s = _kvm_pa2off(kd, pde_pa, &ofs);
270 	if (s < sizeof pde) {
271 		_kvm_syserr(kd, kd->program, "_kvm_vatop: pde_pa not found");
272 		goto invalid;
273 	}
274 	if (lseek(kd->pmfd, ofs, 0) == -1) {
275 		_kvm_err(kd, kd->program, "_kvm_vatop: lseek pde_pa");
276 		goto invalid;
277 	}
278 	if (read(kd->pmfd, &pde, sizeof pde) != sizeof pde) {
279 		_kvm_syserr(kd, kd->program, "_kvm_vatop: read pde");
280 		goto invalid;
281 	}
282 	if (((u_long)pde & PG_V) == 0) {
283 		_kvm_err(kd, kd->program, "_kvm_vatop: pde not valid");
284 		goto invalid;
285 	}
286 
287 	if ((u_long)pde & PG_PS) {
288 	      /*
289 	       * No final-level page table; ptd describes one 2MB page.
290 	       */
291 #define	PAGE2M_MASK	(NBPDR - 1)
292 #define	PG_FRAME2M	(~PAGE2M_MASK)
293 		a = ((u_long)pde & PG_FRAME2M) + (va & PAGE2M_MASK);
294 		s = _kvm_pa2off(kd, a, pa);
295 		if (s == 0) {
296 			_kvm_err(kd, kd->program,
297 			    "_kvm_vatop: 2MB page address not in dump");
298 			goto invalid;
299 		} else
300 			return (NBPDR - (va & PAGE2M_MASK));
301 	}
302 
303 	pteindex = (va >> PAGE_SHIFT) & (NPTEPG-1);
304 	pte_pa = ((u_long)pde & PG_FRAME) + (pteindex * sizeof(pt_entry_t));
305 
306 	s = _kvm_pa2off(kd, pte_pa, &ofs);
307 	if (s < sizeof pte) {
308 		_kvm_err(kd, kd->program, "_kvm_vatop: pte_pa not found");
309 		goto invalid;
310 	}
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_vatop: 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 int
338 _kvm_kvatop(kvm_t *kd, u_long va, off_t *pa)
339 {
340 
341 	if (kd->vmst->minidump)
342 		return (_kvm_minidump_kvatop(kd, va, pa));
343 	if (ISALIVE(kd)) {
344 		_kvm_err(kd, 0, "kvm_kvatop called in live kernel!");
345 		return (0);
346 	}
347 	return (_kvm_vatop(kd, va, pa));
348 }
349