1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2008, Juniper Networks, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the author nor the names of any co-contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #include <sys/cdefs.h>
32 #include <sys/param.h>
33 #include <sys/endian.h>
34 #include <sys/kerneldump.h>
35 #include <sys/mman.h>
36
37 #include <elf.h>
38 #include <kvm.h>
39 #include <limits.h>
40 #include <stdlib.h>
41 #include <string.h>
42
43 #include "kvm_private.h"
44
45 struct vmstate {
46 void *map;
47 size_t mapsz;
48 size_t dmphdrsz;
49 Elf32_Ehdr *eh;
50 Elf32_Phdr *ph;
51 };
52
53 static int
valid_elf_header(Elf32_Ehdr * eh)54 valid_elf_header(Elf32_Ehdr *eh)
55 {
56
57 if (!IS_ELF(*eh))
58 return (0);
59 if (eh->e_ident[EI_CLASS] != ELFCLASS32)
60 return (0);
61 if (eh->e_ident[EI_DATA] != ELFDATA2MSB)
62 return (0);
63 if (eh->e_ident[EI_VERSION] != EV_CURRENT)
64 return (0);
65 if (eh->e_ident[EI_OSABI] != ELFOSABI_STANDALONE)
66 return (0);
67 if (be16toh(eh->e_type) != ET_CORE)
68 return (0);
69 if (be16toh(eh->e_machine) != EM_PPC)
70 return (0);
71 /* Can't think of anything else to check... */
72 return (1);
73 }
74
75 static size_t
dump_header_size(struct kerneldumpheader * dh)76 dump_header_size(struct kerneldumpheader *dh)
77 {
78
79 if (strcmp(dh->magic, KERNELDUMPMAGIC) != 0)
80 return (0);
81 if (strcmp(dh->architecture, "powerpc") != 0)
82 return (0);
83 /* That should do it... */
84 return (sizeof(*dh));
85 }
86
87 /*
88 * Map the ELF headers into the process' address space. We do this in two
89 * steps: first the ELF header itself and using that information the whole
90 * set of headers.
91 */
92 static int
powerpc_maphdrs(kvm_t * kd)93 powerpc_maphdrs(kvm_t *kd)
94 {
95 struct vmstate *vm;
96 size_t mapsz;
97
98 vm = kd->vmst;
99
100 vm->mapsz = sizeof(*vm->eh) + sizeof(struct kerneldumpheader);
101 vm->map = mmap(NULL, vm->mapsz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
102 if (vm->map == MAP_FAILED) {
103 _kvm_err(kd, kd->program, "cannot map corefile");
104 return (-1);
105 }
106 vm->dmphdrsz = 0;
107 vm->eh = vm->map;
108 if (!valid_elf_header(vm->eh)) {
109 /*
110 * Hmmm, no ELF header. Maybe we still have a dump header.
111 * This is normal when the core file wasn't created by
112 * savecore(8), but instead was dumped over TFTP. We can
113 * easily skip the dump header...
114 */
115 vm->dmphdrsz = dump_header_size(vm->map);
116 if (vm->dmphdrsz == 0)
117 goto inval;
118 vm->eh = (void *)((uintptr_t)vm->map + vm->dmphdrsz);
119 if (!valid_elf_header(vm->eh))
120 goto inval;
121 }
122 mapsz = be16toh(vm->eh->e_phentsize) * be16toh(vm->eh->e_phnum) +
123 be32toh(vm->eh->e_phoff);
124 munmap(vm->map, vm->mapsz);
125
126 /* Map all headers. */
127 vm->mapsz = vm->dmphdrsz + mapsz;
128 vm->map = mmap(NULL, vm->mapsz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
129 if (vm->map == MAP_FAILED) {
130 _kvm_err(kd, kd->program, "cannot map corefile headers");
131 return (-1);
132 }
133 vm->eh = (void *)((uintptr_t)vm->map + vm->dmphdrsz);
134 vm->ph = (void *)((uintptr_t)vm->eh + be32toh(vm->eh->e_phoff));
135 return (0);
136
137 inval:
138 _kvm_err(kd, kd->program, "invalid corefile");
139 return (-1);
140 }
141
142 /*
143 * Determine the offset within the corefile corresponding the virtual
144 * address. Return the number of contiguous bytes in the corefile or
145 * 0 when the virtual address is invalid.
146 */
147 static size_t
powerpc_va2off(kvm_t * kd,kvaddr_t va,off_t * ofs)148 powerpc_va2off(kvm_t *kd, kvaddr_t va, off_t *ofs)
149 {
150 struct vmstate *vm = kd->vmst;
151 Elf32_Phdr *ph;
152 int nph;
153
154 ph = vm->ph;
155 nph = be16toh(vm->eh->e_phnum);
156 while (nph && (va < be32toh(ph->p_vaddr) ||
157 va >= be32toh(ph->p_vaddr) + be32toh(ph->p_memsz))) {
158 nph--;
159 ph = (void *)((uintptr_t)ph + be16toh(vm->eh->e_phentsize));
160 }
161 if (nph == 0)
162 return (0);
163
164 /* Segment found. Return file offset and range. */
165 *ofs = vm->dmphdrsz + be32toh(ph->p_offset) +
166 (va - be32toh(ph->p_vaddr));
167 return (be32toh(ph->p_memsz) - (va - be32toh(ph->p_vaddr)));
168 }
169
170 static void
_powerpc_freevtop(kvm_t * kd)171 _powerpc_freevtop(kvm_t *kd)
172 {
173 struct vmstate *vm = kd->vmst;
174
175 if (vm->eh != MAP_FAILED)
176 munmap(vm->eh, vm->mapsz);
177 free(vm);
178 kd->vmst = NULL;
179 }
180
181 static int
_powerpc_probe(kvm_t * kd)182 _powerpc_probe(kvm_t *kd)
183 {
184
185 return (_kvm_probe_elf_kernel(kd, ELFCLASS32, EM_PPC) &&
186 kd->nlehdr.e_ident[EI_DATA] == ELFDATA2MSB);
187 }
188
189 static int
_powerpc_initvtop(kvm_t * kd)190 _powerpc_initvtop(kvm_t *kd)
191 {
192
193 kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
194 if (kd->vmst == NULL)
195 return (-1);
196
197 if (powerpc_maphdrs(kd) == -1)
198 return (-1);
199
200 return (0);
201 }
202
203 static int
_powerpc_kvatop(kvm_t * kd,kvaddr_t va,off_t * ofs)204 _powerpc_kvatop(kvm_t *kd, kvaddr_t va, off_t *ofs)
205 {
206 struct vmstate *vm;
207
208 vm = kd->vmst;
209 if (be32toh(vm->ph->p_paddr) == 0xffffffff)
210 return ((int)powerpc_va2off(kd, va, ofs));
211
212 _kvm_err(kd, kd->program, "Raw corefile not supported");
213 return (0);
214 }
215
216 static int
_powerpc_native(kvm_t * kd __unused)217 _powerpc_native(kvm_t *kd __unused)
218 {
219
220 #if defined(__powerpc__) && !defined(__powerpc64__)
221 return (1);
222 #else
223 return (0);
224 #endif
225 }
226
227 static struct kvm_arch kvm_powerpc = {
228 .ka_probe = _powerpc_probe,
229 .ka_initvtop = _powerpc_initvtop,
230 .ka_freevtop = _powerpc_freevtop,
231 .ka_kvatop = _powerpc_kvatop,
232 .ka_native = _powerpc_native,
233 };
234
235 KVM_ARCH(kvm_powerpc);
236