1 /* Motorola m68k target-dependent support for GNU/Linux.
2
3 Copyright (C) 1996, 1998, 2000, 2001, 2002, 2003, 2004, 2007, 2008, 2009,
4 2010, 2011 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 3 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, see <http://www.gnu.org/licenses/>. */
20
21 #include "defs.h"
22 #include "gdbcore.h"
23 #include "doublest.h"
24 #include "floatformat.h"
25 #include "frame.h"
26 #include "target.h"
27 #include "gdb_string.h"
28 #include "gdbtypes.h"
29 #include "osabi.h"
30 #include "regcache.h"
31 #include "objfiles.h"
32 #include "symtab.h"
33 #include "m68k-tdep.h"
34 #include "trad-frame.h"
35 #include "frame-unwind.h"
36 #include "glibc-tdep.h"
37 #include "solib-svr4.h"
38 #include "auxv.h"
39 #include "observer.h"
40 #include "elf/common.h"
41 #include "linux-tdep.h"
42
43 /* Offsets (in target ints) into jmp_buf. */
44
45 #define M68K_LINUX_JB_ELEMENT_SIZE 4
46 #define M68K_LINUX_JB_PC 7
47
48 /* Check whether insn1 and insn2 are parts of a signal trampoline. */
49
50 #define IS_SIGTRAMP(insn1, insn2) \
51 (/* addaw #20,sp; moveq #119,d0; trap #0 */ \
52 (insn1 == 0xdefc0014 && insn2 == 0x70774e40) \
53 /* moveq #119,d0; trap #0 */ \
54 || insn1 == 0x70774e40)
55
56 #define IS_RT_SIGTRAMP(insn1, insn2) \
57 (/* movel #173,d0; trap #0 */ \
58 (insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \
59 /* moveq #82,d0; notb d0; trap #0 */ \
60 || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40))
61
62 /* Return non-zero if THIS_FRAME corresponds to a signal trampoline. For
63 the sake of m68k_linux_get_sigtramp_info we also distinguish between
64 non-RT and RT signal trampolines. */
65
66 static int
m68k_linux_pc_in_sigtramp(struct frame_info * this_frame)67 m68k_linux_pc_in_sigtramp (struct frame_info *this_frame)
68 {
69 struct gdbarch *gdbarch = get_frame_arch (this_frame);
70 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
71 CORE_ADDR sp;
72 gdb_byte buf[12];
73 unsigned long insn0, insn1, insn2;
74 CORE_ADDR pc = get_frame_pc (this_frame);
75
76 if (!safe_frame_unwind_memory (this_frame, pc - 4, buf, sizeof (buf)))
77 return 0;
78 insn1 = extract_unsigned_integer (buf + 4, 4, byte_order);
79 insn2 = extract_unsigned_integer (buf + 8, 4, byte_order);
80 if (IS_SIGTRAMP (insn1, insn2))
81 return 1;
82 if (IS_RT_SIGTRAMP (insn1, insn2))
83 return 2;
84
85 insn0 = extract_unsigned_integer (buf, 4, byte_order);
86 if (IS_SIGTRAMP (insn0, insn1))
87 return 1;
88 if (IS_RT_SIGTRAMP (insn0, insn1))
89 return 2;
90
91 insn0 = ((insn0 << 16) & 0xffffffff) | (insn1 >> 16);
92 insn1 = ((insn1 << 16) & 0xffffffff) | (insn2 >> 16);
93 if (IS_SIGTRAMP (insn0, insn1))
94 return 1;
95 if (IS_RT_SIGTRAMP (insn0, insn1))
96 return 2;
97
98 return 0;
99 }
100
101 /* From <asm/sigcontext.h>. */
102 static int m68k_linux_sigcontext_reg_offset[M68K_NUM_REGS] =
103 {
104 2 * 4, /* %d0 */
105 3 * 4, /* %d1 */
106 -1, /* %d2 */
107 -1, /* %d3 */
108 -1, /* %d4 */
109 -1, /* %d5 */
110 -1, /* %d6 */
111 -1, /* %d7 */
112 4 * 4, /* %a0 */
113 5 * 4, /* %a1 */
114 -1, /* %a2 */
115 -1, /* %a3 */
116 -1, /* %a4 */
117 -1, /* %a5 */
118 -1, /* %fp */
119 1 * 4, /* %sp */
120 6 * 4, /* %sr */
121 6 * 4 + 2, /* %pc */
122 8 * 4, /* %fp0 */
123 11 * 4, /* %fp1 */
124 -1, /* %fp2 */
125 -1, /* %fp3 */
126 -1, /* %fp4 */
127 -1, /* %fp5 */
128 -1, /* %fp6 */
129 -1, /* %fp7 */
130 14 * 4, /* %fpcr */
131 15 * 4, /* %fpsr */
132 16 * 4 /* %fpiaddr */
133 };
134
135 static int m68k_uclinux_sigcontext_reg_offset[M68K_NUM_REGS] =
136 {
137 2 * 4, /* %d0 */
138 3 * 4, /* %d1 */
139 -1, /* %d2 */
140 -1, /* %d3 */
141 -1, /* %d4 */
142 -1, /* %d5 */
143 -1, /* %d6 */
144 -1, /* %d7 */
145 4 * 4, /* %a0 */
146 5 * 4, /* %a1 */
147 -1, /* %a2 */
148 -1, /* %a3 */
149 -1, /* %a4 */
150 6 * 4, /* %a5 */
151 -1, /* %fp */
152 1 * 4, /* %sp */
153 7 * 4, /* %sr */
154 7 * 4 + 2, /* %pc */
155 -1, /* %fp0 */
156 -1, /* %fp1 */
157 -1, /* %fp2 */
158 -1, /* %fp3 */
159 -1, /* %fp4 */
160 -1, /* %fp5 */
161 -1, /* %fp6 */
162 -1, /* %fp7 */
163 -1, /* %fpcr */
164 -1, /* %fpsr */
165 -1 /* %fpiaddr */
166 };
167
168 /* From <asm/ucontext.h>. */
169 static int m68k_linux_ucontext_reg_offset[M68K_NUM_REGS] =
170 {
171 6 * 4, /* %d0 */
172 7 * 4, /* %d1 */
173 8 * 4, /* %d2 */
174 9 * 4, /* %d3 */
175 10 * 4, /* %d4 */
176 11 * 4, /* %d5 */
177 12 * 4, /* %d6 */
178 13 * 4, /* %d7 */
179 14 * 4, /* %a0 */
180 15 * 4, /* %a1 */
181 16 * 4, /* %a2 */
182 17 * 4, /* %a3 */
183 18 * 4, /* %a4 */
184 19 * 4, /* %a5 */
185 20 * 4, /* %fp */
186 21 * 4, /* %sp */
187 23 * 4, /* %sr */
188 22 * 4, /* %pc */
189 27 * 4, /* %fp0 */
190 30 * 4, /* %fp1 */
191 33 * 4, /* %fp2 */
192 36 * 4, /* %fp3 */
193 39 * 4, /* %fp4 */
194 42 * 4, /* %fp5 */
195 45 * 4, /* %fp6 */
196 48 * 4, /* %fp7 */
197 24 * 4, /* %fpcr */
198 25 * 4, /* %fpsr */
199 26 * 4 /* %fpiaddr */
200 };
201
202
203 /* Get info about saved registers in sigtramp. */
204
205 struct m68k_linux_sigtramp_info
206 {
207 /* Address of sigcontext. */
208 CORE_ADDR sigcontext_addr;
209
210 /* Offset of registers in `struct sigcontext'. */
211 int *sc_reg_offset;
212 };
213
214 /* Nonzero if running on uClinux. */
215 static int target_is_uclinux;
216
217 static void
m68k_linux_inferior_created(struct target_ops * objfile,int from_tty)218 m68k_linux_inferior_created (struct target_ops *objfile, int from_tty)
219 {
220 /* Record that we will need to re-evaluate whether we are running on a
221 uClinux or normal GNU/Linux target (see m68k_linux_get_sigtramp_info). */
222 target_is_uclinux = -1;
223 }
224
225 static struct m68k_linux_sigtramp_info
m68k_linux_get_sigtramp_info(struct frame_info * this_frame)226 m68k_linux_get_sigtramp_info (struct frame_info *this_frame)
227 {
228 struct gdbarch *gdbarch = get_frame_arch (this_frame);
229 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
230 CORE_ADDR sp;
231 struct m68k_linux_sigtramp_info info;
232
233 if (target_is_uclinux == -1)
234 {
235 /* Determine whether we are running on a uClinux or normal GNU/Linux
236 target so we can use the correct sigcontext layouts. */
237 CORE_ADDR dummy;
238
239 target_is_uclinux
240 = (target_auxv_search (¤t_target, AT_NULL, &dummy) > 0
241 && target_auxv_search (¤t_target, AT_PAGESZ, &dummy) == 0);
242 }
243
244 sp = get_frame_register_unsigned (this_frame, M68K_SP_REGNUM);
245
246 /* Get sigcontext address, it is the third parameter on the stack. */
247 info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4, byte_order);
248
249 if (m68k_linux_pc_in_sigtramp (this_frame) == 2)
250 info.sc_reg_offset = m68k_linux_ucontext_reg_offset;
251 else
252 info.sc_reg_offset = (target_is_uclinux
253 ? m68k_uclinux_sigcontext_reg_offset
254 : m68k_linux_sigcontext_reg_offset);
255 return info;
256 }
257
258 /* Signal trampolines. */
259
260 static struct trad_frame_cache *
m68k_linux_sigtramp_frame_cache(struct frame_info * this_frame,void ** this_cache)261 m68k_linux_sigtramp_frame_cache (struct frame_info *this_frame,
262 void **this_cache)
263 {
264 struct frame_id this_id;
265 struct trad_frame_cache *cache;
266 struct gdbarch *gdbarch = get_frame_arch (this_frame);
267 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
268 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
269 struct m68k_linux_sigtramp_info info;
270 gdb_byte buf[4];
271 int i;
272
273 if (*this_cache)
274 return *this_cache;
275
276 cache = trad_frame_cache_zalloc (this_frame);
277
278 /* FIXME: cagney/2004-05-01: This is is long standing broken code.
279 The frame ID's code address should be the start-address of the
280 signal trampoline and not the current PC within that
281 trampoline. */
282 get_frame_register (this_frame, M68K_SP_REGNUM, buf);
283 /* See the end of m68k_push_dummy_call. */
284 this_id = frame_id_build (extract_unsigned_integer (buf, 4, byte_order)
285 - 4 + 8, get_frame_pc (this_frame));
286 trad_frame_set_id (cache, this_id);
287
288 info = m68k_linux_get_sigtramp_info (this_frame);
289
290 for (i = 0; i < M68K_NUM_REGS; i++)
291 if (info.sc_reg_offset[i] != -1)
292 trad_frame_set_reg_addr (cache, i,
293 info.sigcontext_addr + info.sc_reg_offset[i]);
294
295 *this_cache = cache;
296 return cache;
297 }
298
299 static void
m68k_linux_sigtramp_frame_this_id(struct frame_info * this_frame,void ** this_cache,struct frame_id * this_id)300 m68k_linux_sigtramp_frame_this_id (struct frame_info *this_frame,
301 void **this_cache,
302 struct frame_id *this_id)
303 {
304 struct trad_frame_cache *cache =
305 m68k_linux_sigtramp_frame_cache (this_frame, this_cache);
306 trad_frame_get_id (cache, this_id);
307 }
308
309 static struct value *
m68k_linux_sigtramp_frame_prev_register(struct frame_info * this_frame,void ** this_cache,int regnum)310 m68k_linux_sigtramp_frame_prev_register (struct frame_info *this_frame,
311 void **this_cache,
312 int regnum)
313 {
314 /* Make sure we've initialized the cache. */
315 struct trad_frame_cache *cache =
316 m68k_linux_sigtramp_frame_cache (this_frame, this_cache);
317 return trad_frame_get_register (cache, this_frame, regnum);
318 }
319
320 static int
m68k_linux_sigtramp_frame_sniffer(const struct frame_unwind * self,struct frame_info * this_frame,void ** this_prologue_cache)321 m68k_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
322 struct frame_info *this_frame,
323 void **this_prologue_cache)
324 {
325 return m68k_linux_pc_in_sigtramp (this_frame);
326 }
327
328 static const struct frame_unwind m68k_linux_sigtramp_frame_unwind =
329 {
330 SIGTRAMP_FRAME,
331 default_frame_unwind_stop_reason,
332 m68k_linux_sigtramp_frame_this_id,
333 m68k_linux_sigtramp_frame_prev_register,
334 NULL,
335 m68k_linux_sigtramp_frame_sniffer
336 };
337
338 static void
m68k_linux_init_abi(struct gdbarch_info info,struct gdbarch * gdbarch)339 m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
340 {
341 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
342
343 linux_init_abi (info, gdbarch);
344
345 tdep->jb_pc = M68K_LINUX_JB_PC;
346 tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE;
347
348 /* GNU/Linux uses a calling convention that's similar to SVR4. It
349 returns integer values in %d0/%d1, pointer values in %a0 and
350 floating values in %fp0, just like SVR4, but uses %a1 to pass the
351 address to store a structure value. It also returns small
352 structures in registers instead of memory. */
353 m68k_svr4_init_abi (info, gdbarch);
354 tdep->struct_value_regnum = M68K_A1_REGNUM;
355 tdep->struct_return = reg_struct_return;
356
357 set_gdbarch_decr_pc_after_break (gdbarch, 2);
358
359 frame_unwind_append_unwinder (gdbarch, &m68k_linux_sigtramp_frame_unwind);
360
361 /* Shared library handling. */
362
363 /* GNU/Linux uses SVR4-style shared libraries. */
364 set_solib_svr4_fetch_link_map_offsets (gdbarch,
365 svr4_ilp32_fetch_link_map_offsets);
366
367 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */
368 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
369
370 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
371
372 /* Enable TLS support. */
373 set_gdbarch_fetch_tls_load_module_address (gdbarch,
374 svr4_fetch_objfile_link_map);
375 }
376
377 /* Provide a prototype to silence -Wmissing-prototypes. */
378 extern initialize_file_ftype _initialize_m68k_linux_tdep;
379
380 void
_initialize_m68k_linux_tdep(void)381 _initialize_m68k_linux_tdep (void)
382 {
383 gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX,
384 m68k_linux_init_abi);
385 observer_attach_inferior_created (m68k_linux_inferior_created);
386 }
387