1 /* Target-dependent code for NetBSD/i386.
3 Copyright (C) 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002, 2003,
4 2004, 2007 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/>. */
22 #include "arch-utils.h"
30 #include "gdb_assert.h"
31 #include "gdb_string.h"
33 #include "i386-tdep.h"
34 #include "i387-tdep.h"
35 #include "nbsd-tdep.h"
36 #include "solib-svr4.h"
38 /* From <machine/reg.h>. */
39 static int i386nbsd_r_reg_offset
[] =
59 /* Under NetBSD/i386, signal handler invocations can be identified by the
60 designated code sequence that is used to return from a signal handler.
61 In particular, the return address of a signal handler points to the
62 following code sequence:
67 movl $0x127, %eax # __sigreturn14
70 Each instruction has a unique encoding, so we simply attempt to match
71 the instruction the PC is pointing to with any of the above instructions.
72 If there is a hit, we know the offset to the start of the designated
73 sequence and can then check whether we really are executing in the
74 signal trampoline. If not, -1 is returned, otherwise the offset from the
75 start of the return sequence is returned. */
76 #define RETCODE_INSN1 0x8d
77 #define RETCODE_INSN2 0x50
78 #define RETCODE_INSN3 0x50
79 #define RETCODE_INSN4 0xb8
80 #define RETCODE_INSN5 0xcd
82 #define RETCODE_INSN2_OFF 4
83 #define RETCODE_INSN3_OFF 5
84 #define RETCODE_INSN4_OFF 6
85 #define RETCODE_INSN5_OFF 11
87 static const unsigned char sigtramp_retcode
[] =
89 RETCODE_INSN1
, 0x44, 0x24, 0x10,
92 RETCODE_INSN4
, 0x27, 0x01, 0x00, 0x00,
97 i386nbsd_sigtramp_offset (struct frame_info
*next_frame
)
99 CORE_ADDR pc
= frame_pc_unwind (next_frame
);
100 unsigned char ret
[sizeof(sigtramp_retcode
)], insn
;
104 if (!safe_frame_unwind_memory (next_frame
, pc
, &insn
, 1))
114 /* INSN2 and INSN3 are the same. Read at the location of PC+1
115 to determine if we're actually looking at INSN2 or INSN3. */
116 if (!safe_frame_unwind_memory (next_frame
, pc
+ 1, &insn
, 1))
119 if (insn
== RETCODE_INSN3
)
120 off
= RETCODE_INSN2_OFF
;
122 off
= RETCODE_INSN3_OFF
;
126 off
= RETCODE_INSN4_OFF
;
130 off
= RETCODE_INSN5_OFF
;
139 if (!safe_frame_unwind_memory (next_frame
, pc
, ret
, sizeof (ret
)))
142 if (memcmp (ret
, sigtramp_retcode
, sizeof (ret
)) == 0)
148 /* Return whether the frame preceding NEXT_FRAME corresponds to a
149 NetBSD sigtramp routine. */
152 i386nbsd_sigtramp_p (struct frame_info
*next_frame
)
154 CORE_ADDR pc
= frame_pc_unwind (next_frame
);
157 find_pc_partial_function (pc
, &name
, NULL
, NULL
);
158 return (nbsd_pc_in_sigtramp (pc
, name
)
159 || i386nbsd_sigtramp_offset (next_frame
) >= 0);
162 /* From <machine/signal.h>. */
163 int i386nbsd_sc_reg_offset
[] =
174 13 * 4, /* %eflags */
184 i386nbsd_init_abi (struct gdbarch_info info
, struct gdbarch
*gdbarch
)
186 struct gdbarch_tdep
*tdep
= gdbarch_tdep (gdbarch
);
188 /* Obviously NetBSD is BSD-based. */
189 i386bsd_init_abi (info
, gdbarch
);
191 /* NetBSD has a different `struct reg'. */
192 tdep
->gregset_reg_offset
= i386nbsd_r_reg_offset
;
193 tdep
->gregset_num_regs
= ARRAY_SIZE (i386nbsd_r_reg_offset
);
194 tdep
->sizeof_gregset
= 16 * 4;
196 /* NetBSD has different signal trampoline conventions. */
197 tdep
->sigtramp_start
= 0;
198 tdep
->sigtramp_end
= 0;
199 tdep
->sigtramp_p
= i386nbsd_sigtramp_p
;
201 /* NetBSD uses -freg-struct-return by default. */
202 tdep
->struct_return
= reg_struct_return
;
204 /* NetBSD has a `struct sigcontext' that's different from the
206 tdep
->sc_reg_offset
= i386nbsd_sc_reg_offset
;
207 tdep
->sc_num_regs
= ARRAY_SIZE (i386nbsd_sc_reg_offset
);
213 i386nbsdelf_init_abi (struct gdbarch_info info
, struct gdbarch
*gdbarch
)
215 struct gdbarch_tdep
*tdep
= gdbarch_tdep (gdbarch
);
217 /* It's still NetBSD. */
218 i386nbsd_init_abi (info
, gdbarch
);
221 i386_elf_init_abi (info
, gdbarch
);
223 /* NetBSD ELF uses SVR4-style shared libraries. */
224 set_solib_svr4_fetch_link_map_offsets
225 (gdbarch
, svr4_ilp32_fetch_link_map_offsets
);
227 /* NetBSD ELF uses -fpcc-struct-return by default. */
228 tdep
->struct_return
= pcc_struct_return
;
232 _initialize_i386nbsd_tdep (void)
234 gdbarch_register_osabi (bfd_arch_i386
, 0, GDB_OSABI_NETBSD_ELF
,
235 i386nbsdelf_init_abi
);