path: root/gdb/i386bsd-nat.c

/* Native-dependent code for modern i386 BSD's.
   Copyright 2000, 2001 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 "inferior.h"
#include "regcache.h"

#include "gdb_assert.h"
#include <signal.h>
#include <stddef.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <machine/reg.h>
#include <machine/frame.h>

#ifdef HAVE_SYS_PROCFS_H
#include <sys/procfs.h>
#endif

#ifndef HAVE_GREGSET_T
typedef struct reg gregset_t;
#endif

#ifndef HAVE_FPREGSET_T
typedef struct fpreg fpregset_t;
#endif

#include "gregset.h"


/* In older BSD versions we cannot get at some of the segment
   registers.  FreeBSD for example didn't support the %fs and %gs
   registers until the 3.0 release.  We have autoconf checks for their
   presence, and deal gracefully with their absence.  */

/* Registers we shouldn't try to fetch.  */
#if !defined (CANNOT_FETCH_REGISTER)
#define CANNOT_FETCH_REGISTER(regno) cannot_fetch_register (regno)
#endif

/* Registers we shouldn't try to store.  */
#if !defined (CANNOT_STORE_REGISTER)
#define CANNOT_STORE_REGISTER(regno) cannot_fetch_register (regno)
#endif

/* Offset to the gregset_t location where REG is stored.  */
#define REG_OFFSET(reg) offsetof (gregset_t, reg)

/* At reg_offset[REGNO] you'll find the offset to the gregset_t
   location where the GDB register REGNO is stored.  Unsupported
   registers are marked with `-1'.  */
static int reg_offset[] =
{
  REG_OFFSET (r_eax),
  REG_OFFSET (r_ecx),
  REG_OFFSET (r_edx),
  REG_OFFSET (r_edx),
  REG_OFFSET (r_esp),
  REG_OFFSET (r_ebp),
  REG_OFFSET (r_esi),
  REG_OFFSET (r_edi),
  REG_OFFSET (r_eip),
  REG_OFFSET (r_eflags),
  REG_OFFSET (r_cs),
  REG_OFFSET (r_ss),
  REG_OFFSET (r_ds),
  REG_OFFSET (r_es),
#ifdef HAVE_STRUCT_REG_R_FS
  REG_OFFSET (r_fs),
#else
  -1,
#endif
#ifdef HAVE_STRUCT_REG_R_GS
  REG_OFFSET (r_gs)
#else
  -1
#endif
};

#define REG_ADDR(regset, regno) ((char *) (regset) + reg_offset[regno])

/* Return nonzero if we shouldn't try to fetch register REGNO.  */

static int
cannot_fetch_register (int regno)
{
  return (reg_offset[regno] == -1);
}


/* Transfering the registers between GDB, inferiors and core files.  */

/* Fill GDB's register array with the general-purpose register values
   in *GREGSETP.  */

void
supply_gregset (gregset_t *gregsetp)
{
  int i;

  for (i = 0; i < NUM_GREGS; i++)
    {
      if (CANNOT_FETCH_REGISTER (i))
	supply_register (i, NULL);
      else
	supply_register (i, REG_ADDR (gregsetp, i));
    }
}

/* Fill register REGNO (if it is a general-purpose register) in
   *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
   do this for all registers.  */

void
fill_gregset (gregset_t *gregsetp, int regno)
{
  int i;

  for (i = 0; i < NUM_GREGS; i++)
    if ((regno == -1 || regno == i) && ! CANNOT_STORE_REGISTER (i))
      memcpy (REG_ADDR (gregsetp, i), &registers[REGISTER_BYTE (i)],
	      REGISTER_RAW_SIZE (i));
}

#include "i387-nat.h"

/* Fill GDB's register array with the floating-point register values
   in *FPREGSETP.  */

void
supply_fpregset (fpregset_t *fpregsetp)
{
  i387_supply_fsave ((char *) fpregsetp);
}

/* Fill register REGNO (if it is a floating-point register) in
   *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
   do this for all registers.  */

void
fill_fpregset (fpregset_t *fpregsetp, int regno)
{
  i387_fill_fsave ((char *) fpregsetp, regno);
}

/* Fetch register REGNO from the inferior.  If REGNO is -1, do this
   for all registers (including the floating point registers).  */

void
fetch_inferior_registers (int regno)
{
  gregset_t gregs;

  if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
              (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
    perror_with_name ("Couldn't get registers");

  supply_gregset (&gregs);

  if (regno == -1 || regno >= FP0_REGNUM)
    {
      fpregset_t fpregs;

      if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
		  (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
	perror_with_name ("Couldn't get floating point status");

      supply_fpregset (&fpregs);
    }
}

/* Store register REGNO back into the inferior.  If REGNO is -1, do
   this for all registers (including the floating point registers).  */

void
store_inferior_registers (int regno)
{
  gregset_t gregs;

  if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
              (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
    perror_with_name ("Couldn't get registers");

  fill_gregset (&gregs, regno);

  if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
	      (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
    perror_with_name ("Couldn't write registers");

  if (regno == -1 || regno >= FP0_REGNUM)
    {
      fpregset_t fpregs;

      if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
		  (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
	perror_with_name ("Couldn't get floating point status");

      fill_fpregset (&fpregs, regno);
  
      if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
		  (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
	perror_with_name ("Couldn't write floating point status");
    }
}


/* Support for debug registers.  */

#ifdef HAVE_PT_GETDBREGS

/* Not all versions of FreeBSD/i386 that support the debug registers
   have this macro.  */
#ifndef DBREG_DRX
#define DBREG_DRX(d, x) ((&d->dr0)[x])
#endif

static void
i386bsd_dr_set (int regnum, unsigned int value)
{
  struct dbreg dbregs;

  if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
              (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
    perror_with_name ("Couldn't get debug registers");

  /* For some mysterious reason, some of the reserved bits in the
     debug control register get set.  Mask these off, otherwise the
     ptrace call below will fail.  */
  dbregs.dr7 &= ~(0x0000fc00);

  DBREG_DRX ((&dbregs), regnum) = value;

  if (ptrace (PT_SETDBREGS, PIDGET (inferior_ptid),
              (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
    perror_with_name ("Couldn't write debug registers");
}

void
i386bsd_dr_set_control (unsigned long control)
{
  i386bsd_dr_set (7, control);
}

void
i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
{
  gdb_assert (regnum >= 0 && regnum <= 4);

  i386bsd_dr_set (regnum, addr);
}

void
i386bsd_dr_reset_addr (int regnum)
{
  gdb_assert (regnum >= 0 && regnum <= 4);

  i386bsd_dr_set (regnum, 0);
}

unsigned long
i386bsd_dr_get_status (void)
{
  struct dbreg dbregs;

  /* FIXME: kettenis/2001-03-31: Calling perror_with_name if the
     ptrace call fails breaks debugging remote targets.  The correct
     way to fix this is to add the hardware breakpoint and watchpoint
     stuff to the target vector.  For now, just return zero if the
     ptrace call fails.  */
  if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
	      (PTRACE_ARG3_TYPE) & dbregs, 0) == -1)
#if 0
    perror_with_name ("Couldn't read debug registers");
#else
    return 0;
#endif

  return dbregs.dr6;
}

#endif /* PT_GETDBREGS */


/* Support for the user struct.  */

/* Return the address register REGNO.  BLOCKEND is the value of
   u.u_ar0, which should point to the registers.  */

CORE_ADDR
register_u_addr (CORE_ADDR blockend, int regno)
{
  return (CORE_ADDR) REG_ADDR (blockend, regno);
}

#include <sys/param.h>
#include <sys/user.h>

/* Return the size of the user struct.  */

int
kernel_u_size (void)
{
  return (sizeof (struct user));
}

/* See i386bsd-tdep.c.  */
extern int i386bsd_sigcontext_pc_offset;

#include <sys/sysctl.h>

void
_initialize_i386bsd_nat (void)
{
  /* To support the recognition of signal handlers, i386bsd-tdep.c
     hardcodes some constants.  Inclusion of this file means that we
     are compiling a native debugger, which means that we can use the
     system header files and sysctl(3) to get at the relevant
     information.  */

  /* Override the default value for the offset of the program counter
     in the sigcontext structure.  */
  i386bsd_sigcontext_pc_offset = offsetof (struct sigcontext, sc_pc);

  /* FreeBSD provides a kern.ps_strings sysctl that we can use to
     locate the sigtramp.  That way we can still recognize a sigtramp
     if it's location is changed in a new kernel.  Of course this is
     still based on the assumption that the sigtramp is placed
     directly under the location where the program arguments and
     environment can be found.  */
#ifdef KERN_PS_STRINGS
  {
    int mib[2];
    int ps_strings;
    size_t len;

    mib[0] = CTL_KERN;
    mib[1] = KERN_PS_STRINGS;
    len = sizeof (ps_strings);
    if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
      {
	i386bsd_sigtramp_start = ps_strings - 128;
	i386bsd_sigtramp_end = ps_strings;
      }
  }
#endif
}