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/* Target-dependent code for OpenBSD/i386.
Copyright 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002,
2003, 2004
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 2 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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "defs.h"
#include "arch-utils.h"
#include "frame.h"
#include "gdbcore.h"
#include "regcache.h"
#include "regset.h"
#include "symtab.h"
#include "objfiles.h"
#include "osabi.h"
#include "target.h"
#include "gdb_assert.h"
#include "gdb_string.h"
#include "i386-tdep.h"
#include "i387-tdep.h"
#include "solib-svr4.h"
/* Support for signal handlers. */
/* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
in virtual memory. The randomness makes it somewhat tricky to
detect it, but fortunately we can rely on the fact that the start
of the sigtramp routine is page-aligned. By the way, the mapping
is read-only, so you cannot place a breakpoint in the signal
trampoline. */
/* Default page size. */
static const int i386obsd_page_size = 4096;
/* Return whether the frame preceding NEXT_FRAME corresponds to an
OpenBSD sigtramp routine. */
static int
i386obsd_sigtramp_p (struct frame_info *next_frame)
{
CORE_ADDR pc = frame_pc_unwind (next_frame);
CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1));
const char sigreturn[] =
{
0xb8,
0x67, 0x00, 0x00, 0x00, /* movl $SYS_sigreturn, %eax */
0xcd, 0x80 /* int $0x80 */
};
size_t buflen = sizeof sigreturn;
char *name, *buf;
/* If the function has a valid symbol name, it isn't a
trampoline. */
find_pc_partial_function (pc, &name, NULL, NULL);
if (name != NULL)
return 0;
/* If the function lives in a valid section (even without a starting
point) it isn't a trampoline. */
if (find_pc_section (pc) != NULL)
return 0;
/* Allocate buffer. */
buf = alloca (buflen);
/* If we can't read the instructions at START_PC, return zero. */
if (!safe_frame_unwind_memory (next_frame, start_pc + 0x0a, buf, buflen))
return 0;
/* Check for sigreturn(2). */
if (memcmp (buf, sigreturn, buflen) == 0)
return 1;
/* If we can't read the instructions at START_PC, return zero. */
if (!safe_frame_unwind_memory (next_frame, start_pc + 0x14, buf, buflen))
return 0;
/* Check for sigreturn(2) (again). */
if (memcmp (buf, sigreturn, buflen) == 0)
return 1;
return 0;
}
/* Mapping between the general-purpose registers in `struct reg'
format and GDB's register cache layout. */
/* From <machine/reg.h>. */
static int i386obsd_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 */
};
static void
i386obsd_aout_supply_regset (const struct regset *regset,
struct regcache *regcache, int regnum,
const void *regs, size_t len)
{
const struct gdbarch_tdep *tdep = gdbarch_tdep (regset->arch);
gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE);
i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset);
i387_supply_fsave (regcache, regnum, (char *) regs + tdep->sizeof_gregset);
}
static const struct regset *
i386obsd_aout_regset_from_core_section (struct gdbarch *gdbarch,
const char *sect_name,
size_t sect_size)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
/* OpenBSD a.out core dumps don't use seperate register sets for the
general-purpose and floating-point registers. */
if (strcmp (sect_name, ".reg") == 0
&& sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE)
{
if (tdep->gregset == NULL)
tdep->gregset =
regset_alloc (gdbarch, i386obsd_aout_supply_regset, NULL);
return tdep->gregset;
}
return NULL;
}
/* Sigtramp routine location for OpenBSD 3.1 and earlier releases. */
CORE_ADDR i386obsd_sigtramp_start_addr = 0xbfbfdf20;
CORE_ADDR i386obsd_sigtramp_end_addr = 0xbfbfdff0;
/* From <machine/signal.h>. */
int i386obsd_sc_reg_offset[I386_NUM_GREGS] =
{
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
i386obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
/* Obviously OpenBSD is BSD-based. */
i386bsd_init_abi (info, gdbarch);
/* OpenBSD has a different `struct reg'. */
tdep->gregset_reg_offset = i386obsd_r_reg_offset;
tdep->gregset_num_regs = ARRAY_SIZE (i386obsd_r_reg_offset);
tdep->sizeof_gregset = 16 * 4;
/* OpenBSD uses -freg-struct-return by default. */
tdep->struct_return = reg_struct_return;
/* OpenBSD uses a different memory layout. */
tdep->sigtramp_start = i386obsd_sigtramp_start_addr;
tdep->sigtramp_end = i386obsd_sigtramp_end_addr;
tdep->sigtramp_p = i386obsd_sigtramp_p;
/* OpenBSD has a `struct sigcontext' that's different from the
original 4.3 BSD. */
tdep->sc_reg_offset = i386obsd_sc_reg_offset;
tdep->sc_num_regs = ARRAY_SIZE (i386obsd_sc_reg_offset);
}
/* OpenBSD a.out. */
static void
i386obsd_aout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
i386obsd_init_abi (info, gdbarch);
/* OpenBSD a.out has a single register set. */
set_gdbarch_regset_from_core_section
(gdbarch, i386obsd_aout_regset_from_core_section);
}
/* OpenBSD ELF. */
static void
i386obsd_elf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
/* It's still OpenBSD. */
i386obsd_init_abi (info, gdbarch);
/* But ELF-based. */
i386_elf_init_abi (info, gdbarch);
/* OpenBSD ELF uses SVR4-style shared libraries. */
set_gdbarch_in_solib_call_trampoline
(gdbarch, generic_in_solib_call_trampoline);
set_solib_svr4_fetch_link_map_offsets
(gdbarch, svr4_ilp32_fetch_link_map_offsets);
}
/* Provide a prototype to silence -Wmissing-prototypes. */
void _initialize_i386obsd_tdep (void);
void
_initialize_i386obsd_tdep (void)
{
/* FIXME: kettenis/20021020: Since OpenBSD/i386 binaries are
indistingushable from NetBSD/i386 a.out binaries, building a GDB
that should support both these targets will probably not work as
expected. */
#define GDB_OSABI_OPENBSD_AOUT GDB_OSABI_NETBSD_AOUT
gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_OPENBSD_AOUT,
i386obsd_aout_init_abi);
gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_OPENBSD_ELF,
i386obsd_elf_init_abi);
}
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