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
44struct vmstate {
45	void		*map;
46	size_t		mapsz;
47	size_t		dmphdrsz;
48	Elf32_Ehdr	*eh;
49	Elf32_Phdr	*ph;
50};
51
52static int
53valid_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
74static size_t
75dump_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 */
91static int
92powerpc_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 */
146static size_t
147powerpc_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
169static void
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
180static int
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
188static int
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
202static int
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
215static int
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
226static 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
234KVM_ARCH(kvm_powerpc);
235