xref: /freebsd/lib/libkvm/kvm_amd64.c (revision 87569f75a91f298c52a71823c04d41cf53c88889)
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  * AMD64 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)		(amd64_btop(x))
73 #define	ptob(x)		(amd64_ptob(x))
74 #endif
75 
76 struct vmstate {
77 	void		*mmapbase;
78 	size_t		mmapsize;
79 	pml4_entry_t	*PML4;
80 };
81 
82 /*
83  * Map the ELF headers into the process' address space. We do this in two
84  * steps: first the ELF header itself and using that information the whole
85  * set of headers. (Taken from kvm_ia64.c)
86  */
87 static int
88 _kvm_maphdrs(kvm_t *kd, size_t sz)
89 {
90 	struct vmstate *vm = kd->vmst;
91 
92 	/* munmap() previous mmap(). */
93 	if (vm->mmapbase != NULL) {
94 		munmap(vm->mmapbase, vm->mmapsize);
95 		vm->mmapbase = NULL;
96 	}
97 
98 	vm->mmapsize = sz;
99 	vm->mmapbase = mmap(NULL, sz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
100 	if (vm->mmapbase == MAP_FAILED) {
101 		_kvm_err(kd, kd->program, "cannot mmap corefile");
102 		return (-1);
103 	}
104 	return (0);
105 }
106 
107 /*
108  * Translate a physical memory address to a file-offset in the crash-dump.
109  * (Taken from kvm_ia64.c)
110  */
111 static size_t
112 _kvm_pa2off(kvm_t *kd, uint64_t pa, off_t *ofs)
113 {
114 	Elf_Ehdr *e = kd->vmst->mmapbase;
115 	Elf_Phdr *p = (Elf_Phdr*)((char*)e + e->e_phoff);
116 	int n = e->e_phnum;
117 
118 	while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
119 		p++, n--;
120 	if (n == 0)
121 		return (0);
122 	*ofs = (pa - p->p_paddr) + p->p_offset;
123 	return (PAGE_SIZE - ((size_t)pa & PAGE_MASK));
124 }
125 
126 void
127 _kvm_freevtop(kvm_t *kd)
128 {
129 	struct vmstate *vm = kd->vmst;
130 
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 
149 	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
150 	if (kd->vmst == 0) {
151 		_kvm_err(kd, kd->program, "cannot allocate vm");
152 		return (-1);
153 	}
154 	kd->vmst->PML4 = 0;
155 
156 	if (_kvm_maphdrs(kd, sizeof(Elf_Ehdr)) == -1)
157 		return (-1);
158 
159 	ehdr = kd->vmst->mmapbase;
160 	hdrsz = ehdr->e_phoff + ehdr->e_phentsize * ehdr->e_phnum;
161 	if (_kvm_maphdrs(kd, hdrsz) == -1)
162 		return (-1);
163 
164 	nlist[0].n_name = "kernbase";
165 	nlist[1].n_name = 0;
166 
167 	if (kvm_nlist(kd, nlist) != 0) {
168 		_kvm_err(kd, kd->program, "bad namelist - no kernbase");
169 		return (-1);
170 	}
171 	kernbase = nlist[0].n_value;
172 
173 	nlist[0].n_name = "KPML4phys";
174 	nlist[1].n_name = 0;
175 
176 	if (kvm_nlist(kd, nlist) != 0) {
177 		_kvm_err(kd, kd->program, "bad namelist - no KPML4phys");
178 		return (-1);
179 	}
180 	if (kvm_read(kd, (nlist[0].n_value - kernbase), &pa, sizeof(pa)) !=
181 	    sizeof(pa)) {
182 		_kvm_err(kd, kd->program, "cannot read KPML4phys");
183 		return (-1);
184 	}
185 	PML4 = _kvm_malloc(kd, PAGE_SIZE);
186 	if (kvm_read(kd, pa, PML4, PAGE_SIZE) != PAGE_SIZE) {
187 		_kvm_err(kd, kd->program, "cannot read KPML4phys");
188 		return (-1);
189 	}
190 	kd->vmst->PML4 = PML4;
191 	return (0);
192 }
193 
194 static int
195 _kvm_vatop(kvm_t *kd, u_long va, off_t *pa)
196 {
197 	struct vmstate *vm;
198 	u_long offset;
199 	u_long pdpe_pa;
200 	u_long pde_pa;
201 	u_long pte_pa;
202 	pml4_entry_t pml4e;
203 	pdp_entry_t pdpe;
204 	pd_entry_t pde;
205 	pt_entry_t pte;
206 	u_long pml4eindex;
207 	u_long pdpeindex;
208 	u_long pdeindex;
209 	u_long pteindex;
210 	int i;
211 	u_long a;
212 	off_t ofs;
213 	size_t s;
214 
215 	vm = kd->vmst;
216 	offset = va & (PAGE_SIZE - 1);
217 
218 	/*
219 	 * If we are initializing (kernel page table descriptor pointer
220 	 * not yet set) then return pa == va to avoid infinite recursion.
221 	 */
222 	if (vm->PML4 == 0) {
223 		s = _kvm_pa2off(kd, va, pa);
224 		if (s == 0) {
225 			_kvm_err(kd, kd->program,
226 			    "_kvm_vatop: bootstrap data not in dump");
227 			goto invalid;
228 		} else
229 			return (PAGE_SIZE - offset);
230 	}
231 
232 	pml4eindex = (va >> PML4SHIFT) & (NPML4EPG - 1);
233 	pml4e = vm->PML4[pml4eindex];
234 	if (((u_long)pml4e & PG_V) == 0) {
235 		_kvm_err(kd, kd->program, "_kvm_vatop: pml4e not valid");
236 		goto invalid;
237 	}
238 
239 	pdpeindex = (va >> PDPSHIFT) & (NPDPEPG-1);
240 	pdpe_pa = ((u_long)pml4e & PG_FRAME) +
241 	    (pdpeindex * sizeof(pdp_entry_t));
242 
243 	s = _kvm_pa2off(kd, pdpe_pa, &ofs);
244 	if (s < sizeof pdpe) {
245 		_kvm_err(kd, kd->program, "_kvm_vatop: pdpe_pa not found");
246 		goto invalid;
247 	}
248 	if (lseek(kd->pmfd, ofs, 0) == -1) {
249 		_kvm_syserr(kd, kd->program, "_kvm_vatop: lseek pdpe_pa");
250 		goto invalid;
251 	}
252 	if (read(kd->pmfd, &pdpe, sizeof pdpe) != sizeof pdpe) {
253 		_kvm_syserr(kd, kd->program, "_kvm_vatop: read pdpe");
254 		goto invalid;
255 	}
256 	if (((u_long)pdpe & PG_V) == 0) {
257 		_kvm_err(kd, kd->program, "_kvm_vatop: pdpe not valid");
258 		goto invalid;
259 	}
260 
261 	pdeindex = (va >> PDRSHIFT) & (NPDEPG-1);
262 	pde_pa = ((u_long)pdpe & PG_FRAME) + (pdeindex * sizeof(pd_entry_t));
263 
264 	s = _kvm_pa2off(kd, pde_pa, &ofs);
265 	if (s < sizeof pde) {
266 		_kvm_syserr(kd, kd->program, "_kvm_vatop: pde_pa not found");
267 		goto invalid;
268 	}
269 	if (lseek(kd->pmfd, ofs, 0) == -1) {
270 		_kvm_err(kd, kd->program, "_kvm_vatop: lseek pde_pa");
271 		goto invalid;
272 	}
273 	if (read(kd->pmfd, &pde, sizeof pde) != sizeof pde) {
274 		_kvm_syserr(kd, kd->program, "_kvm_vatop: read pde");
275 		goto invalid;
276 	}
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 final-level page table; ptd describes one 2MB page.
285 	       */
286 #define	PAGE2M_MASK	(NBPDR - 1)
287 #define	PG_FRAME2M	(~PAGE2M_MASK)
288 		a = ((u_long)pde & PG_FRAME2M) + (va & PAGE2M_MASK);
289 		s = _kvm_pa2off(kd, a, pa);
290 		if (s == 0) {
291 			_kvm_err(kd, kd->program,
292 			    "_kvm_vatop: 2MB page address not in dump");
293 			goto invalid;
294 		} else
295 			return (NBPDR - (va & PAGE2M_MASK));
296 	}
297 
298 	pteindex = (va >> PAGE_SHIFT) & (NPTEPG-1);
299 	pte_pa = ((u_long)pde & PG_FRAME) + (pteindex * sizeof(pt_entry_t));
300 
301 	s = _kvm_pa2off(kd, pte_pa, &ofs);
302 	if (s < sizeof pte) {
303 		_kvm_err(kd, kd->program, "_kvm_vatop: pte_pa not found");
304 		goto invalid;
305 	}
306 	if (lseek(kd->pmfd, ofs, 0) == -1) {
307 		_kvm_syserr(kd, kd->program, "_kvm_vatop: lseek");
308 		goto invalid;
309 	}
310 	if (read(kd->pmfd, &pte, sizeof pte) != sizeof pte) {
311 		_kvm_syserr(kd, kd->program, "_kvm_vatop: read");
312 		goto invalid;
313 	}
314 	if (((u_long)pte & PG_V) == 0) {
315 		_kvm_err(kd, kd->program, "_kvm_vatop: pte not valid");
316 		goto invalid;
317 	}
318 
319 	a = ((u_long)pte & PG_FRAME) + offset;
320 	s = _kvm_pa2off(kd, a, pa);
321 	if (s == 0) {
322 		_kvm_err(kd, kd->program, "_kvm_vatop: address not in dump");
323 		goto invalid;
324 	} else
325 		return (PAGE_SIZE - offset);
326 
327 invalid:
328 	_kvm_err(kd, 0, "invalid address (0x%lx)", va);
329 	return (0);
330 }
331 
332 int
333 _kvm_kvatop(kvm_t *kd, u_long va, off_t *pa)
334 {
335 
336 	if (ISALIVE(kd)) {
337 		_kvm_err(kd, 0, "kvm_kvatop called in live kernel!");
338 		return (0);
339 	}
340 	return (_kvm_vatop(kd, va, pa));
341 }
342