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("$FreeBSD$");
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#include <string.h>
45
46#include "kvm_private.h"
47
48struct vmstate {
49	void		*map;
50	size_t		mapsz;
51	size_t		dmphdrsz;
52	Elf64_Ehdr	*eh;
53	Elf64_Phdr	*ph;
54};
55
56static int
57valid_elf_header(Elf64_Ehdr *eh)
58{
59
60	if (!IS_ELF(*eh))
61		return (0);
62	if (eh->e_ident[EI_CLASS] != ELFCLASS64)
63		return (0);
64	if (eh->e_ident[EI_DATA] != ELFDATA2MSB)
65		return (0);
66	if (eh->e_ident[EI_VERSION] != EV_CURRENT)
67		return (0);
68	if (eh->e_ident[EI_OSABI] != ELFOSABI_STANDALONE)
69		return (0);
70	if (be16toh(eh->e_type) != ET_CORE)
71		return (0);
72	if (be16toh(eh->e_machine) != EM_PPC64)
73		return (0);
74	/* Can't think of anything else to check... */
75	return (1);
76}
77
78static size_t
79dump_header_size(struct kerneldumpheader *dh)
80{
81
82	if (strcmp(dh->magic, KERNELDUMPMAGIC) != 0)
83		return (0);
84	if (strcmp(dh->architecture, "powerpc64") != 0)
85		return (0);
86	/* That should do it... */
87	return (sizeof(*dh));
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.
94 */
95static int
96powerpc_maphdrs(kvm_t *kd)
97{
98	struct vmstate *vm;
99	size_t mapsz;
100
101	vm = kd->vmst;
102
103	vm->mapsz = PAGE_SIZE;
104	vm->map = mmap(NULL, vm->mapsz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
105	if (vm->map == MAP_FAILED) {
106		_kvm_err(kd, kd->program, "cannot map corefile");
107		return (-1);
108	}
109	vm->dmphdrsz = 0;
110	vm->eh = vm->map;
111	if (!valid_elf_header(vm->eh)) {
112		/*
113		 * Hmmm, no ELF header. Maybe we still have a dump header.
114		 * This is normal when the core file wasn't created by
115		 * savecore(8), but instead was dumped over TFTP. We can
116		 * easily skip the dump header...
117		 */
118		vm->dmphdrsz = dump_header_size(vm->map);
119		if (vm->dmphdrsz == 0)
120			goto inval;
121		vm->eh = (void *)((uintptr_t)vm->map + vm->dmphdrsz);
122		if (!valid_elf_header(vm->eh))
123			goto inval;
124	}
125	mapsz = be16toh(vm->eh->e_phentsize) * be16toh(vm->eh->e_phnum) +
126	    be64toh(vm->eh->e_phoff);
127	munmap(vm->map, vm->mapsz);
128
129	/* Map all headers. */
130	vm->mapsz = vm->dmphdrsz + mapsz;
131	vm->map = mmap(NULL, vm->mapsz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
132	if (vm->map == MAP_FAILED) {
133		_kvm_err(kd, kd->program, "cannot map corefle headers");
134		return (-1);
135	}
136	vm->eh = (void *)((uintptr_t)vm->map + vm->dmphdrsz);
137	vm->ph = (void *)((uintptr_t)vm->eh + be64toh(vm->eh->e_phoff));
138	return (0);
139
140 inval:
141	munmap(vm->map, vm->mapsz);
142	vm->map = MAP_FAILED;
143	_kvm_err(kd, kd->program, "invalid corefile");
144	return (-1);
145}
146
147/*
148 * Determine the offset within the corefile corresponding the virtual
149 * address. Return the number of contiguous bytes in the corefile or
150 * 0 when the virtual address is invalid.
151 */
152static size_t
153powerpc64_va2off(kvm_t *kd, u_long va, off_t *ofs)
154{
155	struct vmstate *vm = kd->vmst;
156	Elf64_Phdr *ph;
157	int nph;
158
159	ph = vm->ph;
160	nph = be16toh(vm->eh->e_phnum);
161	while (nph && (va < be64toh(ph->p_vaddr) ||
162	    va >= be64toh(ph->p_vaddr) + be64toh(ph->p_memsz))) {
163		nph--;
164		ph = (void *)((uintptr_t)ph + be16toh(vm->eh->e_phentsize));
165	}
166	if (nph == 0)
167		return (0);
168
169	/* Segment found. Return file offset and range. */
170	*ofs = vm->dmphdrsz + be64toh(ph->p_offset) +
171	    (va - be64toh(ph->p_vaddr));
172	return (be64toh(ph->p_memsz) - (va - be64toh(ph->p_vaddr)));
173}
174
175void
176_kvm_freevtop(kvm_t *kd)
177{
178	struct vmstate *vm = kd->vmst;
179
180	if (vm == NULL)
181		return;
182
183	if (vm->eh != MAP_FAILED) {
184		munmap(vm->eh, vm->mapsz);
185		vm->eh = MAP_FAILED;
186	}
187	free(vm);
188	kd->vmst = NULL;
189}
190
191int
192_kvm_initvtop(kvm_t *kd)
193{
194
195	kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
196	if (kd->vmst == NULL) {
197		_kvm_err(kd, kd->program, "out of virtual memory");
198		return (-1);
199	}
200	if (powerpc_maphdrs(kd) == -1) {
201		free(kd->vmst);
202		kd->vmst = NULL;
203		return (-1);
204	}
205	return (0);
206}
207
208int
209_kvm_kvatop(kvm_t *kd, u_long va, off_t *ofs)
210{
211	struct vmstate *vm;
212
213	vm = kd->vmst;
214	if (vm->ph->p_paddr == ~0UL)
215		return ((int)powerpc64_va2off(kd, va, ofs));
216
217	_kvm_err(kd, kd->program, "Raw corefile not supported");
218	return (0);
219}
220