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/param.h>
32 #include <sys/endian.h>
33 #include <sys/kerneldump.h>
34 #include <sys/mman.h>
35
36 #include <elf.h>
37 #include <kvm.h>
38 #include <limits.h>
39 #include <stdlib.h>
40 #include <string.h>
41
42 #include "kvm_private.h"
43
44 struct vmstate {
45 void *map;
46 size_t mapsz;
47 size_t dmphdrsz;
48 Elf32_Ehdr *eh;
49 Elf32_Phdr *ph;
50 };
51
52 static int
valid_elf_header(Elf32_Ehdr * eh)53 valid_elf_header(Elf32_Ehdr *eh)
54 {
55
56 if (!IS_ELF(*eh))
57 return (0);
58 if (eh->e_ident[EI_CLASS] != ELFCLASS32)
59 return (0);
60 if (eh->e_ident[EI_DATA] != ELFDATA2MSB)
61 return (0);
62 if (eh->e_ident[EI_VERSION] != EV_CURRENT)
63 return (0);
64 if (eh->e_ident[EI_OSABI] != ELFOSABI_STANDALONE)
65 return (0);
66 if (be16toh(eh->e_type) != ET_CORE)
67 return (0);
68 if (be16toh(eh->e_machine) != EM_PPC)
69 return (0);
70 /* Can't think of anything else to check... */
71 return (1);
72 }
73
74 static size_t
dump_header_size(struct kerneldumpheader * dh)75 dump_header_size(struct kerneldumpheader *dh)
76 {
77
78 if (strcmp(dh->magic, KERNELDUMPMAGIC) != 0)
79 return (0);
80 if (strcmp(dh->architecture, "powerpc") != 0)
81 return (0);
82 /* That should do it... */
83 return (sizeof(*dh));
84 }
85
86 /*
87 * Map the ELF headers into the process' address space. We do this in two
88 * steps: first the ELF header itself and using that information the whole
89 * set of headers.
90 */
91 static int
powerpc_maphdrs(kvm_t * kd)92 powerpc_maphdrs(kvm_t *kd)
93 {
94 struct vmstate *vm;
95 size_t mapsz;
96
97 vm = kd->vmst;
98
99 vm->mapsz = sizeof(*vm->eh) + sizeof(struct kerneldumpheader);
100 vm->map = mmap(NULL, vm->mapsz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
101 if (vm->map == MAP_FAILED) {
102 _kvm_err(kd, kd->program, "cannot map corefile");
103 return (-1);
104 }
105 vm->dmphdrsz = 0;
106 vm->eh = vm->map;
107 if (!valid_elf_header(vm->eh)) {
108 /*
109 * Hmmm, no ELF header. Maybe we still have a dump header.
110 * This is normal when the core file wasn't created by
111 * savecore(8), but instead was dumped over TFTP. We can
112 * easily skip the dump header...
113 */
114 vm->dmphdrsz = dump_header_size(vm->map);
115 if (vm->dmphdrsz == 0)
116 goto inval;
117 vm->eh = (void *)((uintptr_t)vm->map + vm->dmphdrsz);
118 if (!valid_elf_header(vm->eh))
119 goto inval;
120 }
121 mapsz = be16toh(vm->eh->e_phentsize) * be16toh(vm->eh->e_phnum) +
122 be32toh(vm->eh->e_phoff);
123 munmap(vm->map, vm->mapsz);
124
125 /* Map all headers. */
126 vm->mapsz = vm->dmphdrsz + mapsz;
127 vm->map = mmap(NULL, vm->mapsz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
128 if (vm->map == MAP_FAILED) {
129 _kvm_err(kd, kd->program, "cannot map corefile headers");
130 return (-1);
131 }
132 vm->eh = (void *)((uintptr_t)vm->map + vm->dmphdrsz);
133 vm->ph = (void *)((uintptr_t)vm->eh + be32toh(vm->eh->e_phoff));
134 return (0);
135
136 inval:
137 _kvm_err(kd, kd->program, "invalid corefile");
138 return (-1);
139 }
140
141 /*
142 * Determine the offset within the corefile corresponding the virtual
143 * address. Return the number of contiguous bytes in the corefile or
144 * 0 when the virtual address is invalid.
145 */
146 static size_t
powerpc_va2off(kvm_t * kd,kvaddr_t va,off_t * ofs)147 powerpc_va2off(kvm_t *kd, kvaddr_t va, off_t *ofs)
148 {
149 struct vmstate *vm = kd->vmst;
150 Elf32_Phdr *ph;
151 int nph;
152
153 ph = vm->ph;
154 nph = be16toh(vm->eh->e_phnum);
155 while (nph && (va < be32toh(ph->p_vaddr) ||
156 va >= be32toh(ph->p_vaddr) + be32toh(ph->p_memsz))) {
157 nph--;
158 ph = (void *)((uintptr_t)ph + be16toh(vm->eh->e_phentsize));
159 }
160 if (nph == 0)
161 return (0);
162
163 /* Segment found. Return file offset and range. */
164 *ofs = vm->dmphdrsz + be32toh(ph->p_offset) +
165 (va - be32toh(ph->p_vaddr));
166 return (be32toh(ph->p_memsz) - (va - be32toh(ph->p_vaddr)));
167 }
168
169 static void
_powerpc_freevtop(kvm_t * kd)170 _powerpc_freevtop(kvm_t *kd)
171 {
172 struct vmstate *vm = kd->vmst;
173
174 if (vm->eh != MAP_FAILED)
175 munmap(vm->eh, vm->mapsz);
176 free(vm);
177 kd->vmst = NULL;
178 }
179
180 static int
_powerpc_probe(kvm_t * kd)181 _powerpc_probe(kvm_t *kd)
182 {
183
184 return (_kvm_probe_elf_kernel(kd, ELFCLASS32, EM_PPC) &&
185 kd->nlehdr.e_ident[EI_DATA] == ELFDATA2MSB);
186 }
187
188 static int
_powerpc_initvtop(kvm_t * kd)189 _powerpc_initvtop(kvm_t *kd)
190 {
191
192 kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
193 if (kd->vmst == NULL)
194 return (-1);
195
196 if (powerpc_maphdrs(kd) == -1)
197 return (-1);
198
199 return (0);
200 }
201
202 static int
_powerpc_kvatop(kvm_t * kd,kvaddr_t va,off_t * ofs)203 _powerpc_kvatop(kvm_t *kd, kvaddr_t va, off_t *ofs)
204 {
205 struct vmstate *vm;
206
207 vm = kd->vmst;
208 if (be32toh(vm->ph->p_paddr) == 0xffffffff)
209 return ((int)powerpc_va2off(kd, va, ofs));
210
211 _kvm_err(kd, kd->program, "Raw corefile not supported");
212 return (0);
213 }
214
215 static int
_powerpc_native(kvm_t * kd __unused)216 _powerpc_native(kvm_t *kd __unused)
217 {
218
219 #if defined(__powerpc__) && !defined(__powerpc64__)
220 return (1);
221 #else
222 return (0);
223 #endif
224 }
225
226 static struct kvm_arch kvm_powerpc = {
227 .ka_probe = _powerpc_probe,
228 .ka_initvtop = _powerpc_initvtop,
229 .ka_freevtop = _powerpc_freevtop,
230 .ka_kvatop = _powerpc_kvatop,
231 .ka_native = _powerpc_native,
232 };
233
234 KVM_ARCH(kvm_powerpc);
235