1 /* Motorola m68k target-dependent support for GNU/Linux.
3 Copyright (C) 1996, 1998, 2000, 2001, 2002, 2003, 2004, 2007
4 Free Software Foundation, Inc.
6 This file is part of GDB.
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.
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.
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/>. */
24 #include "floatformat.h"
27 #include "gdb_string.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"
40 #include "elf/common.h"
42 /* Offsets (in target ints) into jmp_buf. */
44 #define M68K_LINUX_JB_ELEMENT_SIZE 4
45 #define M68K_LINUX_JB_PC 7
47 /* Check whether insn1 and insn2 are parts of a signal trampoline. */
49 #define IS_SIGTRAMP(insn1, insn2) \
50 (/* addaw #20,sp; moveq #119,d0; trap #0 */ \
51 (insn1 == 0xdefc0014 && insn2 == 0x70774e40) \
52 /* moveq #119,d0; trap #0 */ \
53 || insn1 == 0x70774e40)
55 #define IS_RT_SIGTRAMP(insn1, insn2) \
56 (/* movel #173,d0; trap #0 */ \
57 (insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \
58 /* moveq #82,d0; notb d0; trap #0 */ \
59 || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40))
61 /* Return non-zero if PC points into the signal trampoline. For the
62 sake of m68k_linux_get_sigtramp_info we also distinguish between
63 non-RT and RT signal trampolines. */
66 m68k_linux_pc_in_sigtramp (CORE_ADDR pc
, char *name
)
70 unsigned long insn0
, insn1
, insn2
;
72 if (read_memory_nobpt (pc
- 4, buf
, sizeof (buf
)))
74 insn1
= extract_unsigned_integer (buf
+ 4, 4);
75 insn2
= extract_unsigned_integer (buf
+ 8, 4);
76 if (IS_SIGTRAMP (insn1
, insn2
))
78 if (IS_RT_SIGTRAMP (insn1
, insn2
))
81 insn0
= extract_unsigned_integer (buf
, 4);
82 if (IS_SIGTRAMP (insn0
, insn1
))
84 if (IS_RT_SIGTRAMP (insn0
, insn1
))
87 insn0
= ((insn0
<< 16) & 0xffffffff) | (insn1
>> 16);
88 insn1
= ((insn1
<< 16) & 0xffffffff) | (insn2
>> 16);
89 if (IS_SIGTRAMP (insn0
, insn1
))
91 if (IS_RT_SIGTRAMP (insn0
, insn1
))
97 /* From <asm/sigcontext.h>. */
98 static int m68k_linux_sigcontext_reg_offset
[M68K_NUM_REGS
] =
128 16 * 4 /* %fpiaddr */
131 static int m68k_uclinux_sigcontext_reg_offset
[M68K_NUM_REGS
] =
164 /* From <asm/ucontext.h>. */
165 static int m68k_linux_ucontext_reg_offset
[M68K_NUM_REGS
] =
195 26 * 4 /* %fpiaddr */
199 /* Get info about saved registers in sigtramp. */
201 struct m68k_linux_sigtramp_info
203 /* Address of sigcontext. */
204 CORE_ADDR sigcontext_addr
;
206 /* Offset of registers in `struct sigcontext'. */
210 /* Nonzero if running on uClinux. */
211 static int target_is_uclinux
;
214 m68k_linux_inferior_created (struct target_ops
*objfile
, int from_tty
)
216 /* Record that we will need to re-evaluate whether we are running on a
217 uClinux or normal GNU/Linux target (see m68k_linux_get_sigtramp_info). */
218 target_is_uclinux
= -1;
221 static struct m68k_linux_sigtramp_info
222 m68k_linux_get_sigtramp_info (struct frame_info
*next_frame
)
226 struct m68k_linux_sigtramp_info info
;
228 if (target_is_uclinux
== -1)
230 /* Determine whether we are running on a uClinux or normal GNU/Linux
231 target so we can use the correct sigcontext layouts. */
236 = target_auxv_search (¤t_target
, AT_NULL
, &dummy
) > 0
237 && target_auxv_search (¤t_target
, AT_PAGESZ
, &dummy
) == 0;
240 frame_unwind_register (next_frame
, M68K_SP_REGNUM
, buf
);
241 sp
= extract_unsigned_integer (buf
, 4);
243 /* Get sigcontext address, it is the third parameter on the stack. */
244 info
.sigcontext_addr
= read_memory_unsigned_integer (sp
+ 8, 4);
246 if (m68k_linux_pc_in_sigtramp (frame_pc_unwind (next_frame
), 0) == 2)
247 info
.sc_reg_offset
= m68k_linux_ucontext_reg_offset
;
250 = target_is_uclinux
? m68k_uclinux_sigcontext_reg_offset
251 : m68k_linux_sigcontext_reg_offset
;
255 /* Signal trampolines. */
257 static struct trad_frame_cache
*
258 m68k_linux_sigtramp_frame_cache (struct frame_info
*next_frame
,
261 struct frame_id this_id
;
262 struct trad_frame_cache
*cache
;
263 struct gdbarch_tdep
*tdep
= gdbarch_tdep (get_frame_arch (next_frame
));
264 struct m68k_linux_sigtramp_info info
;
271 cache
= trad_frame_cache_zalloc (next_frame
);
273 /* FIXME: cagney/2004-05-01: This is is long standing broken code.
274 The frame ID's code address should be the start-address of the
275 signal trampoline and not the current PC within that
277 frame_unwind_register (next_frame
, M68K_SP_REGNUM
, buf
);
278 /* See the end of m68k_push_dummy_call. */
279 this_id
= frame_id_build (extract_unsigned_integer (buf
, 4) - 4 + 8,
280 frame_pc_unwind (next_frame
));
281 trad_frame_set_id (cache
, this_id
);
283 info
= m68k_linux_get_sigtramp_info (next_frame
);
285 for (i
= 0; i
< M68K_NUM_REGS
; i
++)
286 if (info
.sc_reg_offset
[i
] != -1)
287 trad_frame_set_reg_addr (cache
, i
,
288 info
.sigcontext_addr
+ info
.sc_reg_offset
[i
]);
295 m68k_linux_sigtramp_frame_this_id (struct frame_info
*next_frame
,
297 struct frame_id
*this_id
)
299 struct trad_frame_cache
*cache
=
300 m68k_linux_sigtramp_frame_cache (next_frame
, this_cache
);
301 trad_frame_get_id (cache
, this_id
);
305 m68k_linux_sigtramp_frame_prev_register (struct frame_info
*next_frame
,
307 int regnum
, int *optimizedp
,
308 enum lval_type
*lvalp
,
310 int *realnump
, gdb_byte
*valuep
)
312 /* Make sure we've initialized the cache. */
313 struct trad_frame_cache
*cache
=
314 m68k_linux_sigtramp_frame_cache (next_frame
, this_cache
);
315 trad_frame_get_register (cache
, next_frame
, regnum
, optimizedp
, lvalp
,
316 addrp
, realnump
, valuep
);
319 static const struct frame_unwind m68k_linux_sigtramp_frame_unwind
=
322 m68k_linux_sigtramp_frame_this_id
,
323 m68k_linux_sigtramp_frame_prev_register
326 static const struct frame_unwind
*
327 m68k_linux_sigtramp_frame_sniffer (struct frame_info
*next_frame
)
329 CORE_ADDR pc
= frame_pc_unwind (next_frame
);
332 find_pc_partial_function (pc
, &name
, NULL
, NULL
);
333 if (m68k_linux_pc_in_sigtramp (pc
, name
))
334 return &m68k_linux_sigtramp_frame_unwind
;
340 m68k_linux_init_abi (struct gdbarch_info info
, struct gdbarch
*gdbarch
)
342 struct gdbarch_tdep
*tdep
= gdbarch_tdep (gdbarch
);
344 tdep
->jb_pc
= M68K_LINUX_JB_PC
;
345 tdep
->jb_elt_size
= M68K_LINUX_JB_ELEMENT_SIZE
;
347 /* GNU/Linux uses a calling convention that's similar to SVR4. It
348 returns integer values in %d0/%d1, pointer values in %a0 and
349 floating values in %fp0, just like SVR4, but uses %a1 to pass the
350 address to store a structure value. It also returns small
351 structures in registers instead of memory. */
352 m68k_svr4_init_abi (info
, gdbarch
);
353 tdep
->struct_value_regnum
= M68K_A1_REGNUM
;
354 tdep
->struct_return
= reg_struct_return
;
356 set_gdbarch_decr_pc_after_break (gdbarch
, 2);
358 frame_unwind_append_sniffer (gdbarch
, m68k_linux_sigtramp_frame_sniffer
);
360 /* Shared library handling. */
362 /* GNU/Linux uses SVR4-style shared libraries. */
363 set_solib_svr4_fetch_link_map_offsets (gdbarch
,
364 svr4_ilp32_fetch_link_map_offsets
);
366 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */
367 set_gdbarch_skip_solib_resolver (gdbarch
, glibc_skip_solib_resolver
);
369 set_gdbarch_skip_trampoline_code (gdbarch
, find_solib_trampoline_target
);
371 /* Enable TLS support. */
372 set_gdbarch_fetch_tls_load_module_address (gdbarch
,
373 svr4_fetch_objfile_link_map
);
377 _initialize_m68k_linux_tdep (void)
379 gdbarch_register_osabi (bfd_arch_m68k
, 0, GDB_OSABI_LINUX
,
380 m68k_linux_init_abi
);
381 observer_attach_inferior_created (m68k_linux_inferior_created
);