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/* Target-dependent code for NetBSD/i386.
Copyright (C) 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002, 2003,
2004, 2007 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "arch-utils.h"
#include "frame.h"
#include "gdbcore.h"
#include "regcache.h"
#include "regset.h"
#include "osabi.h"
#include "symtab.h"
#include "gdb_assert.h"
#include "gdb_string.h"
#include "i386-tdep.h"
#include "i387-tdep.h"
#include "nbsd-tdep.h"
#include "solib-svr4.h"
/* From <machine/reg.h>. */
static int i386nbsd_r_reg_offset[] =
{
0 * 4, /* %eax */
1 * 4, /* %ecx */
2 * 4, /* %edx */
3 * 4, /* %ebx */
4 * 4, /* %esp */
5 * 4, /* %ebp */
6 * 4, /* %esi */
7 * 4, /* %edi */
8 * 4, /* %eip */
9 * 4, /* %eflags */
10 * 4, /* %cs */
11 * 4, /* %ss */
12 * 4, /* %ds */
13 * 4, /* %es */
14 * 4, /* %fs */
15 * 4 /* %gs */
};
/* Under NetBSD/i386, signal handler invocations can be identified by the
designated code sequence that is used to return from a signal handler.
In particular, the return address of a signal handler points to the
following code sequence:
leal 0x10(%esp), %eax
pushl %eax
pushl %eax
movl $0x127, %eax # __sigreturn14
int $0x80
Each instruction has a unique encoding, so we simply attempt to match
the instruction the PC is pointing to with any of the above instructions.
If there is a hit, we know the offset to the start of the designated
sequence and can then check whether we really are executing in the
signal trampoline. If not, -1 is returned, otherwise the offset from the
start of the return sequence is returned. */
#define RETCODE_INSN1 0x8d
#define RETCODE_INSN2 0x50
#define RETCODE_INSN3 0x50
#define RETCODE_INSN4 0xb8
#define RETCODE_INSN5 0xcd
#define RETCODE_INSN2_OFF 4
#define RETCODE_INSN3_OFF 5
#define RETCODE_INSN4_OFF 6
#define RETCODE_INSN5_OFF 11
static const unsigned char sigtramp_retcode[] =
{
RETCODE_INSN1, 0x44, 0x24, 0x10,
RETCODE_INSN2,
RETCODE_INSN3,
RETCODE_INSN4, 0x27, 0x01, 0x00, 0x00,
RETCODE_INSN5, 0x80,
};
static LONGEST
i386nbsd_sigtramp_offset (struct frame_info *next_frame)
{
CORE_ADDR pc = frame_pc_unwind (next_frame);
unsigned char ret[sizeof(sigtramp_retcode)], insn;
LONGEST off;
int i;
if (!safe_frame_unwind_memory (next_frame, pc, &insn, 1))
return -1;
switch (insn)
{
case RETCODE_INSN1:
off = 0;
break;
case RETCODE_INSN2:
/* INSN2 and INSN3 are the same. Read at the location of PC+1
to determine if we're actually looking at INSN2 or INSN3. */
if (!safe_frame_unwind_memory (next_frame, pc + 1, &insn, 1))
return -1;
if (insn == RETCODE_INSN3)
off = RETCODE_INSN2_OFF;
else
off = RETCODE_INSN3_OFF;
break;
case RETCODE_INSN4:
off = RETCODE_INSN4_OFF;
break;
case RETCODE_INSN5:
off = RETCODE_INSN5_OFF;
break;
default:
return -1;
}
pc -= off;
if (!safe_frame_unwind_memory (next_frame, pc, ret, sizeof (ret)))
return -1;
if (memcmp (ret, sigtramp_retcode, sizeof (ret)) == 0)
return off;
return -1;
}
/* Return whether the frame preceding NEXT_FRAME corresponds to a
NetBSD sigtramp routine. */
static int
i386nbsd_sigtramp_p (struct frame_info *next_frame)
{
CORE_ADDR pc = frame_pc_unwind (next_frame);
char *name;
find_pc_partial_function (pc, &name, NULL, NULL);
return (nbsd_pc_in_sigtramp (pc, name)
|| i386nbsd_sigtramp_offset (next_frame) >= 0);
}
/* From <machine/signal.h>. */
int i386nbsd_sc_reg_offset[] =
{
10 * 4, /* %eax */
9 * 4, /* %ecx */
8 * 4, /* %edx */
7 * 4, /* %ebx */
14 * 4, /* %esp */
6 * 4, /* %ebp */
5 * 4, /* %esi */
4 * 4, /* %edi */
11 * 4, /* %eip */
13 * 4, /* %eflags */
12 * 4, /* %cs */
15 * 4, /* %ss */
3 * 4, /* %ds */
2 * 4, /* %es */
1 * 4, /* %fs */
0 * 4 /* %gs */
};
static void
i386nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
/* Obviously NetBSD is BSD-based. */
i386bsd_init_abi (info, gdbarch);
/* NetBSD has a different `struct reg'. */
tdep->gregset_reg_offset = i386nbsd_r_reg_offset;
tdep->gregset_num_regs = ARRAY_SIZE (i386nbsd_r_reg_offset);
tdep->sizeof_gregset = 16 * 4;
/* NetBSD has different signal trampoline conventions. */
tdep->sigtramp_start = 0;
tdep->sigtramp_end = 0;
tdep->sigtramp_p = i386nbsd_sigtramp_p;
/* NetBSD uses -freg-struct-return by default. */
tdep->struct_return = reg_struct_return;
/* NetBSD has a `struct sigcontext' that's different from the
original 4.3 BSD. */
tdep->sc_reg_offset = i386nbsd_sc_reg_offset;
tdep->sc_num_regs = ARRAY_SIZE (i386nbsd_sc_reg_offset);
}
/* NetBSD ELF. */
static void
i386nbsdelf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
/* It's still NetBSD. */
i386nbsd_init_abi (info, gdbarch);
/* But ELF-based. */
i386_elf_init_abi (info, gdbarch);
/* NetBSD ELF uses SVR4-style shared libraries. */
set_solib_svr4_fetch_link_map_offsets
(gdbarch, svr4_ilp32_fetch_link_map_offsets);
/* NetBSD ELF uses -fpcc-struct-return by default. */
tdep->struct_return = pcc_struct_return;
}
void
_initialize_i386nbsd_tdep (void)
{
gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_NETBSD_ELF,
i386nbsdelf_init_abi);
}
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