1 /* Motorola m68k target-dependent support for GNU/Linux.
3 Copyright (C) 1996-2017 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "floatformat.h"
31 #include "m68k-tdep.h"
32 #include "trad-frame.h"
33 #include "frame-unwind.h"
34 #include "glibc-tdep.h"
35 #include "solib-svr4.h"
38 #include "elf/common.h"
39 #include "linux-tdep.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 THIS_FRAME corresponds to a signal trampoline. For
62 the sake of m68k_linux_get_sigtramp_info we also distinguish between
63 non-RT and RT signal trampolines. */
66 m68k_linux_pc_in_sigtramp (struct frame_info
*this_frame
)
68 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
69 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
71 unsigned long insn0
, insn1
, insn2
;
72 CORE_ADDR pc
= get_frame_pc (this_frame
);
74 if (!safe_frame_unwind_memory (this_frame
, pc
- 4, buf
, sizeof (buf
)))
76 insn1
= extract_unsigned_integer (buf
+ 4, 4, byte_order
);
77 insn2
= extract_unsigned_integer (buf
+ 8, 4, byte_order
);
78 if (IS_SIGTRAMP (insn1
, insn2
))
80 if (IS_RT_SIGTRAMP (insn1
, insn2
))
83 insn0
= extract_unsigned_integer (buf
, 4, byte_order
);
84 if (IS_SIGTRAMP (insn0
, insn1
))
86 if (IS_RT_SIGTRAMP (insn0
, insn1
))
89 insn0
= ((insn0
<< 16) & 0xffffffff) | (insn1
>> 16);
90 insn1
= ((insn1
<< 16) & 0xffffffff) | (insn2
>> 16);
91 if (IS_SIGTRAMP (insn0
, insn1
))
93 if (IS_RT_SIGTRAMP (insn0
, insn1
))
99 /* From <asm/sigcontext.h>. */
100 static int m68k_linux_sigcontext_reg_offset
[M68K_NUM_REGS
] =
130 16 * 4 /* %fpiaddr */
133 static int m68k_uclinux_sigcontext_reg_offset
[M68K_NUM_REGS
] =
166 /* From <asm/ucontext.h>. */
167 static int m68k_linux_ucontext_reg_offset
[M68K_NUM_REGS
] =
197 26 * 4 /* %fpiaddr */
201 /* Get info about saved registers in sigtramp. */
203 struct m68k_linux_sigtramp_info
205 /* Address of sigcontext. */
206 CORE_ADDR sigcontext_addr
;
208 /* Offset of registers in `struct sigcontext'. */
212 /* Nonzero if running on uClinux. */
213 static int target_is_uclinux
;
216 m68k_linux_inferior_created (struct target_ops
*objfile
, int from_tty
)
218 /* Record that we will need to re-evaluate whether we are running on a
219 uClinux or normal GNU/Linux target (see m68k_linux_get_sigtramp_info). */
220 target_is_uclinux
= -1;
223 static struct m68k_linux_sigtramp_info
224 m68k_linux_get_sigtramp_info (struct frame_info
*this_frame
)
226 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
227 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
229 struct m68k_linux_sigtramp_info info
;
231 /* Determine whether we are running on a uClinux or normal GNU/Linux
232 target so we can use the correct sigcontext layouts. */
233 if (target_is_uclinux
== -1)
234 target_is_uclinux
= linux_is_uclinux ();
236 sp
= get_frame_register_unsigned (this_frame
, M68K_SP_REGNUM
);
238 /* Get sigcontext address, it is the third parameter on the stack. */
239 info
.sigcontext_addr
= read_memory_unsigned_integer (sp
+ 8, 4, byte_order
);
241 if (m68k_linux_pc_in_sigtramp (this_frame
) == 2)
242 info
.sc_reg_offset
= m68k_linux_ucontext_reg_offset
;
244 info
.sc_reg_offset
= (target_is_uclinux
245 ? m68k_uclinux_sigcontext_reg_offset
246 : m68k_linux_sigcontext_reg_offset
);
250 /* Signal trampolines. */
252 static struct trad_frame_cache
*
253 m68k_linux_sigtramp_frame_cache (struct frame_info
*this_frame
,
256 struct frame_id this_id
;
257 struct trad_frame_cache
*cache
;
258 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
259 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
260 struct m68k_linux_sigtramp_info info
;
265 return (struct trad_frame_cache
*) *this_cache
;
267 cache
= trad_frame_cache_zalloc (this_frame
);
269 /* FIXME: cagney/2004-05-01: This is is long standing broken code.
270 The frame ID's code address should be the start-address of the
271 signal trampoline and not the current PC within that
273 get_frame_register (this_frame
, M68K_SP_REGNUM
, buf
);
274 /* See the end of m68k_push_dummy_call. */
275 this_id
= frame_id_build (extract_unsigned_integer (buf
, 4, byte_order
)
276 - 4 + 8, get_frame_pc (this_frame
));
277 trad_frame_set_id (cache
, this_id
);
279 info
= m68k_linux_get_sigtramp_info (this_frame
);
281 for (i
= 0; i
< M68K_NUM_REGS
; i
++)
282 if (info
.sc_reg_offset
[i
] != -1)
283 trad_frame_set_reg_addr (cache
, i
,
284 info
.sigcontext_addr
+ info
.sc_reg_offset
[i
]);
291 m68k_linux_sigtramp_frame_this_id (struct frame_info
*this_frame
,
293 struct frame_id
*this_id
)
295 struct trad_frame_cache
*cache
=
296 m68k_linux_sigtramp_frame_cache (this_frame
, this_cache
);
297 trad_frame_get_id (cache
, this_id
);
300 static struct value
*
301 m68k_linux_sigtramp_frame_prev_register (struct frame_info
*this_frame
,
305 /* Make sure we've initialized the cache. */
306 struct trad_frame_cache
*cache
=
307 m68k_linux_sigtramp_frame_cache (this_frame
, this_cache
);
308 return trad_frame_get_register (cache
, this_frame
, regnum
);
312 m68k_linux_sigtramp_frame_sniffer (const struct frame_unwind
*self
,
313 struct frame_info
*this_frame
,
314 void **this_prologue_cache
)
316 return m68k_linux_pc_in_sigtramp (this_frame
);
319 static const struct frame_unwind m68k_linux_sigtramp_frame_unwind
=
322 default_frame_unwind_stop_reason
,
323 m68k_linux_sigtramp_frame_this_id
,
324 m68k_linux_sigtramp_frame_prev_register
,
326 m68k_linux_sigtramp_frame_sniffer
329 /* Register maps for supply/collect regset functions. */
331 static const struct regcache_map_entry m68k_linux_gregmap
[] =
333 { 7, M68K_D1_REGNUM
, 4 }, /* d1 ... d7 */
334 { 7, M68K_A0_REGNUM
, 4 }, /* a0 ... a6 */
335 { 1, M68K_D0_REGNUM
, 4 },
336 { 1, M68K_SP_REGNUM
, 4 },
337 { 1, REGCACHE_MAP_SKIP
, 4 }, /* orig_d0 (skip) */
338 { 1, M68K_PS_REGNUM
, 4 },
339 { 1, M68K_PC_REGNUM
, 4 },
340 /* Ignore 16-bit fields 'fmtvec' and '__fill'. */
344 #define M68K_LINUX_GREGS_SIZE (20 * 4)
346 static const struct regcache_map_entry m68k_linux_fpregmap
[] =
348 { 8, M68K_FP0_REGNUM
, 12 }, /* fp0 ... fp7 */
349 { 1, M68K_FPC_REGNUM
, 4 },
350 { 1, M68K_FPS_REGNUM
, 4 },
351 { 1, M68K_FPI_REGNUM
, 4 },
355 #define M68K_LINUX_FPREGS_SIZE (27 * 4)
359 static const struct regset m68k_linux_gregset
=
362 regcache_supply_regset
, regcache_collect_regset
365 static const struct regset m68k_linux_fpregset
=
368 regcache_supply_regset
, regcache_collect_regset
371 /* Iterate over core file register note sections. */
374 m68k_linux_iterate_over_regset_sections (struct gdbarch
*gdbarch
,
375 iterate_over_regset_sections_cb
*cb
,
377 const struct regcache
*regcache
)
379 cb (".reg", M68K_LINUX_GREGS_SIZE
, &m68k_linux_gregset
, NULL
, cb_data
);
380 cb (".reg2", M68K_LINUX_FPREGS_SIZE
, &m68k_linux_fpregset
, NULL
, cb_data
);
384 m68k_linux_init_abi (struct gdbarch_info info
, struct gdbarch
*gdbarch
)
386 struct gdbarch_tdep
*tdep
= gdbarch_tdep (gdbarch
);
388 linux_init_abi (info
, gdbarch
);
390 tdep
->jb_pc
= M68K_LINUX_JB_PC
;
391 tdep
->jb_elt_size
= M68K_LINUX_JB_ELEMENT_SIZE
;
393 /* GNU/Linux uses a calling convention that's similar to SVR4. It
394 returns integer values in %d0/%d1, pointer values in %a0 and
395 floating values in %fp0, just like SVR4, but uses %a1 to pass the
396 address to store a structure value. It also returns small
397 structures in registers instead of memory. */
398 m68k_svr4_init_abi (info
, gdbarch
);
399 tdep
->struct_value_regnum
= M68K_A1_REGNUM
;
400 tdep
->struct_return
= reg_struct_return
;
402 set_gdbarch_decr_pc_after_break (gdbarch
, 2);
404 frame_unwind_append_unwinder (gdbarch
, &m68k_linux_sigtramp_frame_unwind
);
406 /* Shared library handling. */
408 /* GNU/Linux uses SVR4-style shared libraries. */
409 set_solib_svr4_fetch_link_map_offsets (gdbarch
,
410 svr4_ilp32_fetch_link_map_offsets
);
412 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */
413 set_gdbarch_skip_solib_resolver (gdbarch
, glibc_skip_solib_resolver
);
415 set_gdbarch_skip_trampoline_code (gdbarch
, find_solib_trampoline_target
);
417 /* Core file support. */
418 set_gdbarch_iterate_over_regset_sections
419 (gdbarch
, m68k_linux_iterate_over_regset_sections
);
421 /* Enable TLS support. */
422 set_gdbarch_fetch_tls_load_module_address (gdbarch
,
423 svr4_fetch_objfile_link_map
);
426 /* Provide a prototype to silence -Wmissing-prototypes. */
427 extern initialize_file_ftype _initialize_m68k_linux_tdep
;
430 _initialize_m68k_linux_tdep (void)
432 gdbarch_register_osabi (bfd_arch_m68k
, 0, GDB_OSABI_LINUX
,
433 m68k_linux_init_abi
);
434 observer_attach_inferior_created (m68k_linux_inferior_created
);