darling-gdb/gdb/i386bsd-nat.c

/* Native-dependent code for modern i386 BSD's.

   Copyright 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 "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 "i386-tdep.h"
#include "i387-tdep.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.  */
#undef CANNOT_FETCH_REGISTER
#define CANNOT_FETCH_REGISTER(regnum) cannot_fetch_register (regnum)

/* Registers we shouldn't try to store.  */
#undef CANNOT_STORE_REGISTER
#define CANNOT_STORE_REGISTER(regnum) cannot_fetch_register (regnum)

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

/* At reg_offset[REGNUM] you'll find the offset to the gregset_t
   location where the GDB register REGNUM 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_ebx),
  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, regnum) ((char *) (regset) + reg_offset[regnum])

/* Macro to determine if a register is fetched with PT_GETREGS.  */
#define GETREGS_SUPPLIES(regnum) \
  ((0 <= (regnum) && (regnum) <= 15))

#ifdef HAVE_PT_GETXMMREGS
/* Set to 1 if the kernel supports PT_GETXMMREGS.  Initialized to -1
   so that we try PT_GETXMMREGS the first time around.  */
static int have_ptrace_xmmregs = -1;
#endif

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

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

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

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

static void
supply_gregset (gregset_t *gregsetp)
{
  struct regcache *regcache = current_regcache;
  int regnum;

  for (regnum = 0; regnum < I386_NUM_GREGS; regnum++)
    {
      if (CANNOT_FETCH_REGISTER (regnum))
	regcache_raw_supply (regcache, regnum, NULL);
      else
	regcache_raw_supply (regcache, regnum, REG_ADDR (gregsetp, regnum));
    }
}

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

static void
fill_gregset (gregset_t *gregsetp, int regnum)
{
  struct regcache *regcache = current_regcache;
  int i;

  for (i = 0; i < I386_NUM_GREGS; i++)
    if ((regnum == -1 || regnum == i) && ! CANNOT_STORE_REGISTER (i))
      regcache_raw_collect (regcache, i, REG_ADDR (gregsetp, i));
}



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

void
fetch_inferior_registers (int regnum)
{
  if (regnum == -1 || GETREGS_SUPPLIES (regnum))
    {
      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 (regnum != -1)
	return;
    }

  if (regnum == -1 || regnum >= I386_ST0_REGNUM)
    {
      fpregset_t fpregs;
#ifdef HAVE_PT_GETXMMREGS
      char xmmregs[512];

      if (have_ptrace_xmmregs != 0
	  && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
		    (PTRACE_ARG3_TYPE) xmmregs, 0) == 0)
	{
	  have_ptrace_xmmregs = 1;
	  i387_supply_fxsave (current_regcache, -1, xmmregs);
	}
      else
	{
          if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
		      (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
	    perror_with_name ("Couldn't get floating point status");

	  i387_supply_fsave (current_regcache, -1, &fpregs);
	}
#else
      if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
		  (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
	perror_with_name ("Couldn't get floating point status");

      i387_supply_fsave (current_regcache, -1, &fpregs);
#endif
    }
}

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

void
store_inferior_registers (int regnum)
{
  if (regnum == -1 || GETREGS_SUPPLIES (regnum))
    {
      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, regnum);

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

      if (regnum != -1)
	return;
    }

  if (regnum == -1 || regnum >= I386_ST0_REGNUM)
    {
      fpregset_t fpregs;
#ifdef HAVE_PT_GETXMMREGS
      char xmmregs[512];

      if (have_ptrace_xmmregs != 0
	  && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
		    (PTRACE_ARG3_TYPE) xmmregs, 0) == 0)
	{
	  have_ptrace_xmmregs = 1;

	  i387_collect_fxsave (current_regcache, regnum, xmmregs);

	  if (ptrace (PT_SETXMMREGS, PIDGET (inferior_ptid),
		      (PTRACE_ARG3_TYPE) xmmregs, 0) == -1)
            perror_with_name ("Couldn't write XMM registers");
	}
      else
	{
	  have_ptrace_xmmregs = 0;
#endif
          if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
		      (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
	    perror_with_name ("Couldn't get floating point status");

          i387_collect_fsave (current_regcache, regnum, &fpregs);

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

/* 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.  */
  DBREG_DRX ((&dbregs), 7) &= ~(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 DBREG_DRX ((&dbregs), 6);
}

#endif /* PT_GETDBREGS */


/* Support for the user struct.  */

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

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

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

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

int
kernel_u_size (void)
{
  return (sizeof (struct user));
}

void
_initialize_i386bsd_nat (void)
{
  int offset;

  /* 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.  */

#if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
#define SC_REG_OFFSET i386fbsd4_sc_reg_offset
#elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
#define SC_REG_OFFSET i386fbsd_sc_reg_offset
#elif defined (NetBSD) || defined (__NetBSD_Version__)
#define SC_REG_OFFSET i386nbsd_sc_reg_offset
#elif defined (OpenBSD)
#define SC_REG_OFFSET i386obsd_sc_reg_offset
#else
#define SC_REG_OFFSET i386bsd_sc_reg_offset
#endif

  /* We only check the program counter, stack pointer and frame
     pointer since these members of `struct sigcontext' are essential
     for providing backtraces.  More checks could be added, but would
     involve adding configure checks for the appropriate structure
     members, since older BSD's don't provide all of them.  */

#define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
#define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
#define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]

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

  if (SC_PC_OFFSET != offset)
    {
      warning ("\
offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
Please report this to <bug-gdb@gnu.org>.", 
	       offset, SC_PC_OFFSET);
    }

  SC_PC_OFFSET = offset;

  /* Likewise for the stack pointer.  */
  offset = offsetof (struct sigcontext, sc_sp);

  if (SC_SP_OFFSET != offset)
    {
      warning ("\
offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
Please report this to <bug-gdb@gnu.org>.",
	       offset, SC_SP_OFFSET);
    }

  SC_SP_OFFSET = offset;

  /* And the frame pointer.  */
  offset = offsetof (struct sigcontext, sc_fp);

  if (SC_FP_OFFSET != offset)
    {
      warning ("\
offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
Please report this to <bug-gdb@gnu.org>.",
	       offset, SC_FP_OFFSET);
    }

  SC_FP_OFFSET = offset;
}