kvm_powerpc64.c revision 209881 
1/*-
2 * Copyright (c) 2008, Juniper Networks, Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the author nor the names of any co-contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: head/lib/libkvm/kvm_powerpc64.c 209881 2010-07-10 15:15:00Z nwhitehorn $");
31
32#include <sys/param.h>
33#include <sys/endian.h>
34#include <sys/kerneldump.h>
35#include <sys/mman.h>
36
37#include <vm/vm.h>
38
39#include <db.h>
40#include <elf.h>
41#include <limits.h>
42#include <kvm.h>
43#include <stdlib.h>
44
45#include "kvm_private.h"
46
47struct vmstate {
48	void		*map;
49	size_t		mapsz;
50	size_t		dmphdrsz;
51	Elf64_Ehdr	*eh;
52	Elf64_Phdr	*ph;
53};
54
55static int
56valid_elf_header(Elf64_Ehdr *eh)
57{
58
59	if (!IS_ELF(*eh))
60		return (0);
61	if (eh->e_ident[EI_CLASS] != ELFCLASS64)
62		return (0);
63	if (eh->e_ident[EI_DATA] != ELFDATA2MSB)
64		return (0);
65	if (eh->e_ident[EI_VERSION] != EV_CURRENT)
66		return (0);
67	if (eh->e_ident[EI_OSABI] != ELFOSABI_STANDALONE)
68		return (0);
69	if (be16toh(eh->e_type) != ET_CORE)
70		return (0);
71	if (be16toh(eh->e_machine) != EM_PPC64)
72		return (0);
73	/* Can't think of anything else to check... */
74	return (1);
75}
76
77static size_t
78dump_header_size(struct kerneldumpheader *dh)
79{
80
81	if (strcmp(dh->magic, KERNELDUMPMAGIC) != 0)
82		return (0);
83	if (strcmp(dh->architecture, "powerpc64") != 0)
84		return (0);
85	/* That should do it... */
86	return (sizeof(*dh));
87}
88
89/*
90 * Map the ELF headers into the process' address space. We do this in two
91 * steps: first the ELF header itself and using that information the whole
92 * set of headers.
93 */
94static int
95powerpc_maphdrs(kvm_t *kd)
96{
97	struct vmstate *vm;
98	size_t mapsz;
99
100	vm = kd->vmst;
101
102	vm->mapsz = PAGE_SIZE;
103	vm->map = mmap(NULL, vm->mapsz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
104	if (vm->map == MAP_FAILED) {
105		_kvm_err(kd, kd->program, "cannot map corefile");
106		return (-1);
107	}
108	vm->dmphdrsz = 0;
109	vm->eh = vm->map;
110	if (!valid_elf_header(vm->eh)) {
111		/*
112		 * Hmmm, no ELF header. Maybe we still have a dump header.
113		 * This is normal when the core file wasn't created by
114		 * savecore(8), but instead was dumped over TFTP. We can
115		 * easily skip the dump header...
116		 */
117		vm->dmphdrsz = dump_header_size(vm->map);
118		if (vm->dmphdrsz == 0)
119			goto inval;
120		vm->eh = (void *)((uintptr_t)vm->map + vm->dmphdrsz);
121		if (!valid_elf_header(vm->eh))
122			goto inval;
123	}
124	mapsz = be16toh(vm->eh->e_phentsize) * be16toh(vm->eh->e_phnum) +
125	    be64toh(vm->eh->e_phoff);
126	munmap(vm->map, vm->mapsz);
127
128	/* Map all headers. */
129	vm->mapsz = vm->dmphdrsz + mapsz;
130	vm->map = mmap(NULL, vm->mapsz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
131	if (vm->map == MAP_FAILED) {
132		_kvm_err(kd, kd->program, "cannot map corefle headers");
133		return (-1);
134	}
135	vm->eh = (void *)((uintptr_t)vm->map + vm->dmphdrsz);
136	vm->ph = (void *)((uintptr_t)vm->eh + be64toh(vm->eh->e_phoff));
137	return (0);
138
139 inval:
140	munmap(vm->map, vm->mapsz);
141	vm->map = MAP_FAILED;
142	_kvm_err(kd, kd->program, "invalid corefile");
143	return (-1);
144}
145
146/*
147 * Determine the offset within the corefile corresponding the virtual
148 * address. Return the number of contiguous bytes in the corefile or
149 * 0 when the virtual address is invalid.
150 */
151static size_t
152powerpc64_va2off(kvm_t *kd, u_long va, off_t *ofs)
153{
154	struct vmstate *vm = kd->vmst;
155	Elf64_Phdr *ph;
156	int nph;
157
158	ph = vm->ph;
159	nph = be16toh(vm->eh->e_phnum);
160	while (nph && (va < be64toh(ph->p_vaddr) ||
161	    va >= be64toh(ph->p_vaddr) + be64toh(ph->p_memsz))) {
162		nph--;
163		ph = (void *)((uintptr_t)ph + be16toh(vm->eh->e_phentsize));
164	}
165	if (nph == 0)
166		return (0);
167
168	/* Segment found. Return file offset and range. */
169	*ofs = vm->dmphdrsz + be64toh(ph->p_offset) +
170	    (va - be64toh(ph->p_vaddr));
171	return (be64toh(ph->p_memsz) - (va - be64toh(ph->p_vaddr)));
172}
173
174void
175_kvm_freevtop(kvm_t *kd)
176{
177	struct vmstate *vm = kd->vmst;
178
179	if (vm == NULL)
180		return;
181
182	if (vm->eh != MAP_FAILED) {
183		munmap(vm->eh, vm->mapsz);
184		vm->eh = MAP_FAILED;
185	}
186	free(vm);
187	kd->vmst = NULL;
188}
189
190int
191_kvm_initvtop(kvm_t *kd)
192{
193
194	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
195	if (kd->vmst == NULL) {
196		_kvm_err(kd, kd->program, "out of virtual memory");
197		return (-1);
198	}
199	if (powerpc_maphdrs(kd) == -1) {
200		free(kd->vmst);
201		kd->vmst = NULL;
202		return (-1);
203	}
204	return (0);
205}
206
207int
208_kvm_kvatop(kvm_t *kd, u_long va, off_t *ofs)
209{
210	struct vmstate *vm;
211
212	vm = kd->vmst;
213	if (vm->ph->p_paddr == ~0UL)
214		return ((int)powerpc64_va2off(kd, va, ofs));
215
216	_kvm_err(kd, kd->program, "Raw corefile not supported");
217	return (0);
218}
219