1 /* Motorola m68k target-dependent support for GNU/Linux.
3 Copyright (C) 1996, 1998, 2000, 2001, 2002, 2003, 2004, 2007, 2008
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 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)
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);
76 insn2 = extract_unsigned_integer (buf + 8, 4);
77 if (IS_SIGTRAMP (insn1, insn2))
79 if (IS_RT_SIGTRAMP (insn1, insn2))
82 insn0 = extract_unsigned_integer (buf, 4);
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)
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. */
235 = (target_auxv_search (¤t_target, AT_NULL, &dummy) > 0
236 && target_auxv_search (¤t_target, AT_PAGESZ, &dummy) == 0);
239 sp = get_frame_register_unsigned (this_frame, M68K_SP_REGNUM);
241 /* Get sigcontext address, it is the third parameter on the stack. */
242 info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4);
244 if (m68k_linux_pc_in_sigtramp (this_frame) == 2)
245 info.sc_reg_offset = m68k_linux_ucontext_reg_offset;
247 info.sc_reg_offset = (target_is_uclinux
248 ? m68k_uclinux_sigcontext_reg_offset
249 : m68k_linux_sigcontext_reg_offset);
253 /* Signal trampolines. */
255 static struct trad_frame_cache *
256 m68k_linux_sigtramp_frame_cache (struct frame_info *this_frame,
259 struct frame_id this_id;
260 struct trad_frame_cache *cache;
261 struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
262 struct m68k_linux_sigtramp_info info;
269 cache = trad_frame_cache_zalloc (this_frame);
271 /* FIXME: cagney/2004-05-01: This is is long standing broken code.
272 The frame ID's code address should be the start-address of the
273 signal trampoline and not the current PC within that
275 get_frame_register (this_frame, M68K_SP_REGNUM, buf);
276 /* See the end of m68k_push_dummy_call. */
277 this_id = frame_id_build (extract_unsigned_integer (buf, 4) - 4 + 8,
278 get_frame_pc (this_frame));
279 trad_frame_set_id (cache, this_id);
281 info = m68k_linux_get_sigtramp_info (this_frame);
283 for (i = 0; i < M68K_NUM_REGS; i++)
284 if (info.sc_reg_offset[i] != -1)
285 trad_frame_set_reg_addr (cache, i,
286 info.sigcontext_addr + info.sc_reg_offset[i]);
293 m68k_linux_sigtramp_frame_this_id (struct frame_info *this_frame,
295 struct frame_id *this_id)
297 struct trad_frame_cache *cache =
298 m68k_linux_sigtramp_frame_cache (this_frame, this_cache);
299 trad_frame_get_id (cache, this_id);
302 static struct value *
303 m68k_linux_sigtramp_frame_prev_register (struct frame_info *this_frame,
307 /* Make sure we've initialized the cache. */
308 struct trad_frame_cache *cache =
309 m68k_linux_sigtramp_frame_cache (this_frame, this_cache);
310 return trad_frame_get_register (cache, this_frame, regnum);
314 m68k_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
315 struct frame_info *this_frame,
316 void **this_prologue_cache)
318 return m68k_linux_pc_in_sigtramp (this_frame);
321 static const struct frame_unwind m68k_linux_sigtramp_frame_unwind =
324 m68k_linux_sigtramp_frame_this_id,
325 m68k_linux_sigtramp_frame_prev_register,
327 m68k_linux_sigtramp_frame_sniffer
331 m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
333 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
335 tdep->jb_pc = M68K_LINUX_JB_PC;
336 tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE;
338 /* GNU/Linux uses a calling convention that's similar to SVR4. It
339 returns integer values in %d0/%d1, pointer values in %a0 and
340 floating values in %fp0, just like SVR4, but uses %a1 to pass the
341 address to store a structure value. It also returns small
342 structures in registers instead of memory. */
343 m68k_svr4_init_abi (info, gdbarch);
344 tdep->struct_value_regnum = M68K_A1_REGNUM;
345 tdep->struct_return = reg_struct_return;
347 set_gdbarch_decr_pc_after_break (gdbarch, 2);
349 frame_unwind_append_unwinder (gdbarch, &m68k_linux_sigtramp_frame_unwind);
351 /* Shared library handling. */
353 /* GNU/Linux uses SVR4-style shared libraries. */
354 set_solib_svr4_fetch_link_map_offsets (gdbarch,
355 svr4_ilp32_fetch_link_map_offsets);
357 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */
358 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
360 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
362 /* Enable TLS support. */
363 set_gdbarch_fetch_tls_load_module_address (gdbarch,
364 svr4_fetch_objfile_link_map);
368 _initialize_m68k_linux_tdep (void)
370 gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX,
371 m68k_linux_init_abi);
372 observer_attach_inferior_created (m68k_linux_inferior_created);