kvm_powerpc.c revision 331722 
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: stable/11/lib/libkvm/kvm_powerpc.c 331722 2018-03-29 02:50:57Z eadler $");
31
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
45struct vmstate {
46	void		*map;
47	size_t		mapsz;
48	size_t		dmphdrsz;
49	Elf32_Ehdr	*eh;
50	Elf32_Phdr	*ph;
51};
52
53static int
54valid_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
75static size_t
76dump_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 */
92static int
93powerpc_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 */
147static size_t
148powerpc_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
170static void
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
181static int
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
189static int
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
203static int
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
216static int
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
227static 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
235KVM_ARCH(kvm_powerpc);
236