1 /* Motorola m68k target-dependent support for GNU/Linux.
2
3 Copyright 1996, 1998, 2000, 2001, 2002, 2003, 2004
4 Free Software Foundation, Inc.
5
6 This file is part of GDB.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
22
23 #include "defs.h"
24 #include "gdbcore.h"
25 #include "doublest.h"
26 #include "floatformat.h"
27 #include "frame.h"
28 #include "target.h"
29 #include "gdb_string.h"
30 #include "gdbtypes.h"
31 #include "osabi.h"
32 #include "regcache.h"
33 #include "objfiles.h"
34 #include "symtab.h"
35 #include "m68k-tdep.h"
36 #include "trad-frame.h"
37 #include "frame-unwind.h"
38 #include "glibc-tdep.h"
39 #include "solib-svr4.h"
40
41 /* Offsets (in target ints) into jmp_buf. */
42
43 #define M68K_LINUX_JB_ELEMENT_SIZE 4
44 #define M68K_LINUX_JB_PC 7
45
46 /* Check whether insn1 and insn2 are parts of a signal trampoline. */
47
48 #define IS_SIGTRAMP(insn1, insn2) \
49 (/* addaw #20,sp; moveq #119,d0; trap #0 */ \
50 (insn1 == 0xdefc0014 && insn2 == 0x70774e40) \
51 /* moveq #119,d0; trap #0 */ \
52 || insn1 == 0x70774e40)
53
54 #define IS_RT_SIGTRAMP(insn1, insn2) \
55 (/* movel #173,d0; trap #0 */ \
56 (insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \
57 /* moveq #82,d0; notb d0; trap #0 */ \
58 || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40))
59
60 /* Return non-zero if PC points into the signal trampoline. For the
61 sake of m68k_linux_get_sigtramp_info we also distinguish between
62 non-RT and RT signal trampolines. */
63
64 static int
m68k_linux_pc_in_sigtramp(CORE_ADDR pc,char * name)65 m68k_linux_pc_in_sigtramp (CORE_ADDR pc, char *name)
66 {
67 CORE_ADDR sp;
68 char buf[12];
69 unsigned long insn0, insn1, insn2;
70
71 if (deprecated_read_memory_nobpt (pc - 4, buf, sizeof (buf)))
72 return 0;
73 insn1 = extract_unsigned_integer (buf + 4, 4);
74 insn2 = extract_unsigned_integer (buf + 8, 4);
75 if (IS_SIGTRAMP (insn1, insn2))
76 return 1;
77 if (IS_RT_SIGTRAMP (insn1, insn2))
78 return 2;
79
80 insn0 = extract_unsigned_integer (buf, 4);
81 if (IS_SIGTRAMP (insn0, insn1))
82 return 1;
83 if (IS_RT_SIGTRAMP (insn0, insn1))
84 return 2;
85
86 insn0 = ((insn0 << 16) & 0xffffffff) | (insn1 >> 16);
87 insn1 = ((insn1 << 16) & 0xffffffff) | (insn2 >> 16);
88 if (IS_SIGTRAMP (insn0, insn1))
89 return 1;
90 if (IS_RT_SIGTRAMP (insn0, insn1))
91 return 2;
92
93 return 0;
94 }
95
96 /* From <asm/sigcontext.h>. */
97 static int m68k_linux_sigcontext_reg_offset[M68K_NUM_REGS] =
98 {
99 2 * 4, /* %d0 */
100 3 * 4, /* %d1 */
101 -1, /* %d2 */
102 -1, /* %d3 */
103 -1, /* %d4 */
104 -1, /* %d5 */
105 -1, /* %d6 */
106 -1, /* %d7 */
107 4 * 4, /* %a0 */
108 5 * 4, /* %a1 */
109 -1, /* %a2 */
110 -1, /* %a3 */
111 -1, /* %a4 */
112 -1, /* %a5 */
113 -1, /* %fp */
114 1 * 4, /* %sp */
115 5 * 4 + 2, /* %sr */
116 6 * 4 + 2, /* %pc */
117 8 * 4, /* %fp0 */
118 11 * 4, /* %fp1 */
119 -1, /* %fp2 */
120 -1, /* %fp3 */
121 -1, /* %fp4 */
122 -1, /* %fp5 */
123 -1, /* %fp6 */
124 -1, /* %fp7 */
125 14 * 4, /* %fpcr */
126 15 * 4, /* %fpsr */
127 16 * 4 /* %fpiaddr */
128 };
129
130 /* From <asm/ucontext.h>. */
131 static int m68k_linux_ucontext_reg_offset[M68K_NUM_REGS] =
132 {
133 6 * 4, /* %d0 */
134 7 * 4, /* %d1 */
135 8 * 4, /* %d2 */
136 9 * 4, /* %d3 */
137 10 * 4, /* %d4 */
138 11 * 4, /* %d5 */
139 12 * 4, /* %d6 */
140 13 * 4, /* %d7 */
141 14 * 4, /* %a0 */
142 15 * 4, /* %a1 */
143 16 * 4, /* %a2 */
144 17 * 4, /* %a3 */
145 18 * 4, /* %a4 */
146 19 * 4, /* %a5 */
147 20 * 4, /* %fp */
148 21 * 4, /* %sp */
149 23 * 4, /* %sr */
150 22 * 4, /* %pc */
151 27 * 4, /* %fp0 */
152 30 * 4, /* %fp1 */
153 33 * 4, /* %fp2 */
154 36 * 4, /* %fp3 */
155 39 * 4, /* %fp4 */
156 42 * 4, /* %fp5 */
157 45 * 4, /* %fp6 */
158 48 * 4, /* %fp7 */
159 24 * 4, /* %fpcr */
160 25 * 4, /* %fpsr */
161 26 * 4 /* %fpiaddr */
162 };
163
164
165 /* Get info about saved registers in sigtramp. */
166
167 struct m68k_linux_sigtramp_info
168 {
169 /* Address of sigcontext. */
170 CORE_ADDR sigcontext_addr;
171
172 /* Offset of registers in `struct sigcontext'. */
173 int *sc_reg_offset;
174 };
175
176 static struct m68k_linux_sigtramp_info
m68k_linux_get_sigtramp_info(struct frame_info * next_frame)177 m68k_linux_get_sigtramp_info (struct frame_info *next_frame)
178 {
179 CORE_ADDR sp;
180 char buf[4];
181 struct m68k_linux_sigtramp_info info;
182
183 frame_unwind_register (next_frame, M68K_SP_REGNUM, buf);
184 sp = extract_unsigned_integer (buf, 4);
185
186 /* Get sigcontext address, it is the third parameter on the stack. */
187 info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4);
188
189 if (m68k_linux_pc_in_sigtramp (frame_pc_unwind (next_frame), 0) == 2)
190 info.sc_reg_offset = m68k_linux_ucontext_reg_offset;
191 else
192 info.sc_reg_offset = m68k_linux_sigcontext_reg_offset;
193 return info;
194 }
195
196 /* Signal trampolines. */
197
198 static struct trad_frame_cache *
m68k_linux_sigtramp_frame_cache(struct frame_info * next_frame,void ** this_cache)199 m68k_linux_sigtramp_frame_cache (struct frame_info *next_frame,
200 void **this_cache)
201 {
202 struct frame_id this_id;
203 struct trad_frame_cache *cache;
204 struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
205 struct m68k_linux_sigtramp_info info;
206 char buf[4];
207 int i;
208
209 if (*this_cache)
210 return *this_cache;
211
212 cache = trad_frame_cache_zalloc (next_frame);
213
214 /* FIXME: cagney/2004-05-01: This is is long standing broken code.
215 The frame ID's code address should be the start-address of the
216 signal trampoline and not the current PC within that
217 trampoline. */
218 frame_unwind_register (next_frame, M68K_SP_REGNUM, buf);
219 /* See the end of m68k_push_dummy_call. */
220 this_id = frame_id_build (extract_unsigned_integer (buf, 4) - 4 + 8,
221 frame_pc_unwind (next_frame));
222 trad_frame_set_id (cache, this_id);
223
224 info = m68k_linux_get_sigtramp_info (next_frame);
225
226 for (i = 0; i < M68K_NUM_REGS; i++)
227 if (info.sc_reg_offset[i] != -1)
228 trad_frame_set_reg_addr (cache, i,
229 info.sigcontext_addr + info.sc_reg_offset[i]);
230
231 *this_cache = cache;
232 return cache;
233 }
234
235 static void
m68k_linux_sigtramp_frame_this_id(struct frame_info * next_frame,void ** this_cache,struct frame_id * this_id)236 m68k_linux_sigtramp_frame_this_id (struct frame_info *next_frame,
237 void **this_cache,
238 struct frame_id *this_id)
239 {
240 struct trad_frame_cache *cache =
241 m68k_linux_sigtramp_frame_cache (next_frame, this_cache);
242 trad_frame_get_id (cache, this_id);
243 }
244
245 static void
m68k_linux_sigtramp_frame_prev_register(struct frame_info * next_frame,void ** this_cache,int regnum,int * optimizedp,enum lval_type * lvalp,CORE_ADDR * addrp,int * realnump,void * valuep)246 m68k_linux_sigtramp_frame_prev_register (struct frame_info *next_frame,
247 void **this_cache,
248 int regnum, int *optimizedp,
249 enum lval_type *lvalp,
250 CORE_ADDR *addrp,
251 int *realnump, void *valuep)
252 {
253 /* Make sure we've initialized the cache. */
254 struct trad_frame_cache *cache =
255 m68k_linux_sigtramp_frame_cache (next_frame, this_cache);
256 trad_frame_get_register (cache, next_frame, regnum, optimizedp, lvalp,
257 addrp, realnump, valuep);
258 }
259
260 static const struct frame_unwind m68k_linux_sigtramp_frame_unwind =
261 {
262 SIGTRAMP_FRAME,
263 m68k_linux_sigtramp_frame_this_id,
264 m68k_linux_sigtramp_frame_prev_register
265 };
266
267 static const struct frame_unwind *
m68k_linux_sigtramp_frame_sniffer(struct frame_info * next_frame)268 m68k_linux_sigtramp_frame_sniffer (struct frame_info *next_frame)
269 {
270 CORE_ADDR pc = frame_pc_unwind (next_frame);
271 char *name;
272
273 find_pc_partial_function (pc, &name, NULL, NULL);
274 if (m68k_linux_pc_in_sigtramp (pc, name))
275 return &m68k_linux_sigtramp_frame_unwind;
276
277 return NULL;
278 }
279
280 static void
m68k_linux_init_abi(struct gdbarch_info info,struct gdbarch * gdbarch)281 m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
282 {
283 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
284
285 tdep->jb_pc = M68K_LINUX_JB_PC;
286 tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE;
287
288 /* GNU/Linux uses a calling convention that's similar to SVR4. It
289 returns integer values in %d0/%di, pointer values in %a0 and
290 floating values in %fp0, just like SVR4, but uses %a1 to pass the
291 address to store a structure value. It also returns small
292 structures in registers instead of memory. */
293 m68k_svr4_init_abi (info, gdbarch);
294 tdep->struct_value_regnum = M68K_A1_REGNUM;
295 tdep->struct_return = reg_struct_return;
296
297 frame_unwind_append_sniffer (gdbarch, m68k_linux_sigtramp_frame_sniffer);
298
299 /* Shared library handling. */
300
301 /* GNU/Linux uses SVR4-style shared libraries. */
302 set_solib_svr4_fetch_link_map_offsets (gdbarch,
303 svr4_ilp32_fetch_link_map_offsets);
304
305 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */
306 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
307
308 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
309
310 /* Enable TLS support. */
311 set_gdbarch_fetch_tls_load_module_address (gdbarch,
312 svr4_fetch_objfile_link_map);
313 }
314
315 void
_initialize_m68k_linux_tdep(void)316 _initialize_m68k_linux_tdep (void)
317 {
318 gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX,
319 m68k_linux_init_abi);
320 }
321