1 /* libunwind - a platform-independent unwind library
2 Copyright (C) 2002 Hewlett-Packard Co
3 Copyright (C) 2007 David Mosberger-Tang
4 Contributed by David Mosberger-Tang <dmosberger@gmail.com>
5
6 This file is part of libunwind.
7
8 Permission is hereby granted, free of charge, to any person obtaining
9 a copy of this software and associated documentation files (the
10 "Software"), to deal in the Software without restriction, including
11 without limitation the rights to use, copy, modify, merge, publish,
12 distribute, sublicense, and/or sell copies of the Software, and to
13 permit persons to whom the Software is furnished to do so, subject to
14 the following conditions:
15
16 The above copyright notice and this permission notice shall be
17 included in all copies or substantial portions of the Software.
18
19 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
20 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
21 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
22 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
23 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
24 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
25 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
26
27 #ifdef HAVE_CONFIG_H
28 #include <config.h>
29 #endif
30
31 #include <stdlib.h>
32 #include <string.h>
33
34 #include "unwind_i.h"
35
36 #ifdef UNW_REMOTE_ONLY
37
38 /* unw_local_addr_space is a NULL pointer in this case. */
39 PROTECTED unw_addr_space_t unw_local_addr_space;
40
41 #else /* !UNW_REMOTE_ONLY */
42
43 static struct unw_addr_space local_addr_space;
44
45 PROTECTED unw_addr_space_t unw_local_addr_space = &local_addr_space;
46
47 # ifdef UNW_LOCAL_ONLY
48
49 HIDDEN void *
tdep_uc_addr(ucontext_t * uc,int reg)50 tdep_uc_addr (ucontext_t *uc, int reg)
51 {
52 return x86_r_uc_addr (uc, reg);
53 }
54
55 # endif /* UNW_LOCAL_ONLY */
56
57 HIDDEN unw_dyn_info_list_t _U_dyn_info_list;
58
59 /* XXX fix me: there is currently no way to locate the dyn-info list
60 by a remote unwinder. On ia64, this is done via a special
61 unwind-table entry. Perhaps something similar can be done with
62 DWARF2 unwind info. */
63
64 static void
put_unwind_info(unw_addr_space_t as,unw_proc_info_t * proc_info,void * arg)65 put_unwind_info (unw_addr_space_t as, unw_proc_info_t *proc_info, void *arg)
66 {
67 /* it's a no-op */
68 }
69
70 static int
get_dyn_info_list_addr(unw_addr_space_t as,unw_word_t * dyn_info_list_addr,void * arg)71 get_dyn_info_list_addr (unw_addr_space_t as, unw_word_t *dyn_info_list_addr,
72 void *arg)
73 {
74 *dyn_info_list_addr = (unw_word_t) &_U_dyn_info_list;
75 return 0;
76 }
77
78 /* ANDROID support update. */
79 #ifndef PAGE_SIZE
80 #define PAGE_SIZE 4096
81 #endif
82 /* End of ANDROID update. */
83
84 #define PAGE_START(a) ((a) & ~(PAGE_SIZE-1))
85
86 /* Cache of already validated addresses */
87 #define NLGA 4
88 static unw_word_t last_good_addr[NLGA];
89 static int lga_victim;
90
91 static int
validate_mem(unw_word_t addr)92 validate_mem (unw_word_t addr)
93 {
94 int i, victim;
95 #ifdef HAVE_MINCORE
96 unsigned char mvec[2]; /* Unaligned access may cross page boundary */
97 #endif
98 size_t len;
99
100 if (PAGE_START(addr + sizeof (unw_word_t) - 1) == PAGE_START(addr))
101 len = PAGE_SIZE;
102 else
103 len = PAGE_SIZE * 2;
104
105 addr = PAGE_START(addr);
106
107 if (addr == 0)
108 return -1;
109
110 for (i = 0; i < NLGA; i++)
111 {
112 if (last_good_addr[i] && (addr == last_good_addr[i]))
113 return 0;
114 }
115
116 #ifdef HAVE_MINCORE
117 if (mincore ((void *) addr, len, mvec) == -1)
118 #else
119 if (msync ((void *) addr, len, MS_ASYNC) == -1)
120 #endif
121 return -1;
122
123 victim = lga_victim;
124 for (i = 0; i < NLGA; i++) {
125 if (!last_good_addr[victim]) {
126 last_good_addr[victim++] = addr;
127 return 0;
128 }
129 victim = (victim + 1) % NLGA;
130 }
131
132 /* All slots full. Evict the victim. */
133 last_good_addr[victim] = addr;
134 victim = (victim + 1) % NLGA;
135 lga_victim = victim;
136
137 return 0;
138 }
139
140 static int
access_mem(unw_addr_space_t as,unw_word_t addr,unw_word_t * val,int write,void * arg)141 access_mem (unw_addr_space_t as, unw_word_t addr, unw_word_t *val, int write,
142 void *arg)
143 {
144 if (write)
145 {
146 /* ANDROID support update. */
147 #ifdef UNW_LOCAL_ONLY
148 if (map_local_is_writable (addr, sizeof(unw_word_t)))
149 {
150 #endif
151 Debug (16, "mem[%x] <- %x\n", addr, *val);
152 *(unw_word_t *) addr = *val;
153 #ifdef UNW_LOCAL_ONLY
154 }
155 else
156 {
157 Debug (16, "Unwritable memory mem[%x] <- %x\n", addr, *val);
158 return -1;
159 }
160 #endif
161 /* End of ANDROID update. */
162 }
163 else
164 {
165 /* ANDROID support update. */
166 #ifdef CONSERVATIVE_CHECKS
167 if (validate_mem(addr))
168 return -1;
169 #endif
170 /* End of ANDROID update. */
171
172 /* ANDROID support update. */
173 #ifdef UNW_LOCAL_ONLY
174 if (map_local_is_readable (addr, sizeof(unw_word_t)))
175 {
176 #endif
177 *val = *(unw_word_t *) addr;
178 Debug (16, "mem[%x] -> %x\n", addr, *val);
179 #ifdef UNW_LOCAL_ONLY
180 }
181 else
182 {
183 Debug (16, "Unreadable memory mem[%x] -> XXX\n", addr);
184 return -1;
185 }
186 #endif
187 /* End of ANDROID update. */
188 }
189 return 0;
190 }
191
192 static int
access_reg(unw_addr_space_t as,unw_regnum_t reg,unw_word_t * val,int write,void * arg)193 access_reg (unw_addr_space_t as, unw_regnum_t reg, unw_word_t *val, int write,
194 void *arg)
195 {
196 unw_word_t *addr;
197 ucontext_t *uc = ((struct cursor *)arg)->uc;
198
199 if (unw_is_fpreg (reg))
200 goto badreg;
201
202 if (!(addr = x86_r_uc_addr (uc, reg)))
203 goto badreg;
204
205 if (write)
206 {
207 *(unw_word_t *) addr = *val;
208 Debug (12, "%s <- %x\n", unw_regname (reg), *val);
209 }
210 else
211 {
212 *val = *(unw_word_t *) addr;
213 Debug (12, "%s -> %x\n", unw_regname (reg), *val);
214 }
215 return 0;
216
217 badreg:
218 Debug (1, "bad register number %u\n", reg);
219 return -UNW_EBADREG;
220 }
221
222 static int
access_fpreg(unw_addr_space_t as,unw_regnum_t reg,unw_fpreg_t * val,int write,void * arg)223 access_fpreg (unw_addr_space_t as, unw_regnum_t reg, unw_fpreg_t *val,
224 int write, void *arg)
225 {
226 ucontext_t *uc = ((struct cursor *)arg)->uc;
227 unw_fpreg_t *addr;
228
229 if (!unw_is_fpreg (reg))
230 goto badreg;
231
232 if (!(addr = x86_r_uc_addr (uc, reg)))
233 goto badreg;
234
235 if (write)
236 {
237 Debug (12, "%s <- %08lx.%08lx.%08lx\n", unw_regname (reg),
238 ((long *)val)[0], ((long *)val)[1], ((long *)val)[2]);
239 *(unw_fpreg_t *) addr = *val;
240 }
241 else
242 {
243 *val = *(unw_fpreg_t *) addr;
244 Debug (12, "%s -> %08lx.%08lx.%08lx\n", unw_regname (reg),
245 ((long *)val)[0], ((long *)val)[1], ((long *)val)[2]);
246 }
247 return 0;
248
249 badreg:
250 Debug (1, "bad register number %u\n", reg);
251 /* attempt to access a non-preserved register */
252 return -UNW_EBADREG;
253 }
254
255 static int
get_static_proc_name(unw_addr_space_t as,unw_word_t ip,char * buf,size_t buf_len,unw_word_t * offp,void * arg)256 get_static_proc_name (unw_addr_space_t as, unw_word_t ip,
257 char *buf, size_t buf_len, unw_word_t *offp,
258 void *arg)
259 {
260 return _Uelf32_get_proc_name (as, getpid (), ip, buf, buf_len, offp, arg);
261 }
262
263 static int
access_mem_unrestricted(unw_addr_space_t as,unw_word_t addr,unw_word_t * val,int write,void * arg)264 access_mem_unrestricted (unw_addr_space_t as, unw_word_t addr, unw_word_t *val,
265 int write, void *arg)
266 {
267 if (write)
268 return -1;
269
270 *val = *(unw_word_t *) addr;
271 Debug (16, "mem[%x] -> %x\n", addr, *val);
272 return 0;
273 }
274
275 // This initializes just enough of the address space to call the
276 // access memory function.
277 PROTECTED void
unw_local_access_addr_space_init(unw_addr_space_t as)278 unw_local_access_addr_space_init (unw_addr_space_t as)
279 {
280 memset (as, 0, sizeof (*as));
281 as->acc.access_mem = access_mem_unrestricted;
282 }
283
284 HIDDEN void
x86_local_addr_space_init(void)285 x86_local_addr_space_init (void)
286 {
287 memset (&local_addr_space, 0, sizeof (local_addr_space));
288 local_addr_space.caching_policy = UNW_CACHE_GLOBAL;
289 local_addr_space.acc.find_proc_info = dwarf_find_proc_info;
290 local_addr_space.acc.put_unwind_info = put_unwind_info;
291 local_addr_space.acc.get_dyn_info_list_addr = get_dyn_info_list_addr;
292 local_addr_space.acc.access_mem = access_mem;
293 local_addr_space.acc.access_reg = access_reg;
294 local_addr_space.acc.access_fpreg = access_fpreg;
295 local_addr_space.acc.resume = x86_local_resume;
296 local_addr_space.acc.get_proc_name = get_static_proc_name;
297 unw_flush_cache (&local_addr_space, 0, 0);
298
299 map_local_init ();
300 }
301
302 #endif /* !UNW_REMOTE_ONLY */
303