1 /* Motorola m68k target-dependent support for GNU/Linux.
3 Copyright (C) 1996-2014 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"
41 /* Offsets (in target ints) into jmp_buf. */
43 #define M68K_LINUX_JB_ELEMENT_SIZE 4
44 #define M68K_LINUX_JB_PC 7
46 /* Check whether insn1 and insn2 are parts of a signal trampoline. */
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)
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))
60 /* Return non-zero if THIS_FRAME corresponds to a signal trampoline. For
61 the sake of m68k_linux_get_sigtramp_info we also distinguish between
62 non-RT and RT signal trampolines. */
65 m68k_linux_pc_in_sigtramp (struct frame_info *this_frame)
67 struct gdbarch *gdbarch = get_frame_arch (this_frame);
68 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
70 unsigned long insn0, insn1, insn2;
71 CORE_ADDR pc = get_frame_pc (this_frame);
73 if (!safe_frame_unwind_memory (this_frame, pc - 4, buf, sizeof (buf)))
75 insn1 = extract_unsigned_integer (buf + 4, 4, byte_order);
76 insn2 = extract_unsigned_integer (buf + 8, 4, byte_order);
77 if (IS_SIGTRAMP (insn1, insn2))
79 if (IS_RT_SIGTRAMP (insn1, insn2))
82 insn0 = extract_unsigned_integer (buf, 4, byte_order);
83 if (IS_SIGTRAMP (insn0, insn1))
85 if (IS_RT_SIGTRAMP (insn0, insn1))
88 insn0 = ((insn0 << 16) & 0xffffffff) | (insn1 >> 16);
89 insn1 = ((insn1 << 16) & 0xffffffff) | (insn2 >> 16);
90 if (IS_SIGTRAMP (insn0, insn1))
92 if (IS_RT_SIGTRAMP (insn0, insn1))
98 /* From <asm/sigcontext.h>. */
99 static int m68k_linux_sigcontext_reg_offset[M68K_NUM_REGS] =
129 16 * 4 /* %fpiaddr */
132 static int m68k_uclinux_sigcontext_reg_offset[M68K_NUM_REGS] =
165 /* From <asm/ucontext.h>. */
166 static int m68k_linux_ucontext_reg_offset[M68K_NUM_REGS] =
196 26 * 4 /* %fpiaddr */
200 /* Get info about saved registers in sigtramp. */
202 struct m68k_linux_sigtramp_info
204 /* Address of sigcontext. */
205 CORE_ADDR sigcontext_addr;
207 /* Offset of registers in `struct sigcontext'. */
211 /* Nonzero if running on uClinux. */
212 static int target_is_uclinux;
215 m68k_linux_inferior_created (struct target_ops *objfile, int from_tty)
217 /* Record that we will need to re-evaluate whether we are running on a
218 uClinux or normal GNU/Linux target (see m68k_linux_get_sigtramp_info). */
219 target_is_uclinux = -1;
222 static struct m68k_linux_sigtramp_info
223 m68k_linux_get_sigtramp_info (struct frame_info *this_frame)
225 struct gdbarch *gdbarch = get_frame_arch (this_frame);
226 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
228 struct m68k_linux_sigtramp_info info;
230 /* Determine whether we are running on a uClinux or normal GNU/Linux
231 target so we can use the correct sigcontext layouts. */
232 if (target_is_uclinux == -1)
233 target_is_uclinux = linux_is_uclinux ();
235 sp = get_frame_register_unsigned (this_frame, M68K_SP_REGNUM);
237 /* Get sigcontext address, it is the third parameter on the stack. */
238 info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4, byte_order);
240 if (m68k_linux_pc_in_sigtramp (this_frame) == 2)
241 info.sc_reg_offset = m68k_linux_ucontext_reg_offset;
243 info.sc_reg_offset = (target_is_uclinux
244 ? m68k_uclinux_sigcontext_reg_offset
245 : m68k_linux_sigcontext_reg_offset);
249 /* Signal trampolines. */
251 static struct trad_frame_cache *
252 m68k_linux_sigtramp_frame_cache (struct frame_info *this_frame,
255 struct frame_id this_id;
256 struct trad_frame_cache *cache;
257 struct gdbarch *gdbarch = get_frame_arch (this_frame);
258 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
259 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
260 struct m68k_linux_sigtramp_info info;
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
330 m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
332 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
334 linux_init_abi (info, gdbarch);
336 tdep->jb_pc = M68K_LINUX_JB_PC;
337 tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE;
339 /* GNU/Linux uses a calling convention that's similar to SVR4. It
340 returns integer values in %d0/%d1, pointer values in %a0 and
341 floating values in %fp0, just like SVR4, but uses %a1 to pass the
342 address to store a structure value. It also returns small
343 structures in registers instead of memory. */
344 m68k_svr4_init_abi (info, gdbarch);
345 tdep->struct_value_regnum = M68K_A1_REGNUM;
346 tdep->struct_return = reg_struct_return;
348 set_gdbarch_decr_pc_after_break (gdbarch, 2);
350 frame_unwind_append_unwinder (gdbarch, &m68k_linux_sigtramp_frame_unwind);
352 /* Shared library handling. */
354 /* GNU/Linux uses SVR4-style shared libraries. */
355 set_solib_svr4_fetch_link_map_offsets (gdbarch,
356 svr4_ilp32_fetch_link_map_offsets);
358 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */
359 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
361 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
363 /* Enable TLS support. */
364 set_gdbarch_fetch_tls_load_module_address (gdbarch,
365 svr4_fetch_objfile_link_map);
367 set_gdbarch_get_siginfo_type (gdbarch, linux_get_siginfo_type);
370 /* Provide a prototype to silence -Wmissing-prototypes. */
371 extern initialize_file_ftype _initialize_m68k_linux_tdep;
374 _initialize_m68k_linux_tdep (void)
376 gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX,
377 m68k_linux_init_abi);
378 observer_attach_inferior_created (m68k_linux_inferior_created);