gdb/m68klinux-nat.c

/* Motorola m68k native support for GNU/Linux.

   Copyright (C) 1996, 1998, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
   2008, 2009, 2010, 2011 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 "frame.h"
#include "inferior.h"
#include "language.h"
#include "gdbcore.h"
#include "gdb_string.h"
#include "regcache.h"
#include "target.h"
#include "linux-nat.h"

#include "m68k-tdep.h"

#include <sys/param.h>
#include <sys/dir.h>
#include <signal.h>
#include <sys/ptrace.h>
#include <sys/user.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <sys/procfs.h>

#ifdef HAVE_SYS_REG_H
#include <sys/reg.h>
#endif

#include <sys/file.h>
#include "gdb_stat.h"

#include "floatformat.h"

#include "target.h"

/* Prototypes for supply_gregset etc.  */
#include "gregset.h"

/* This table must line up with gdbarch_register_name in "m68k-tdep.c".  */
static const int regmap[] =
{
  PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  PT_SR, PT_PC,
  /* PT_FP0, ..., PT_FP7 */
  21, 24, 27, 30, 33, 36, 39, 42,
  /* PT_FPCR, PT_FPSR, PT_FPIAR */
  45, 46, 47
};

/* Which ptrace request retrieves which registers?
   These apply to the corresponding SET requests as well.  */
#define NUM_GREGS (18)
#define MAX_NUM_REGS (NUM_GREGS + 11)

int
getregs_supplies (int regno)
{
  return 0 <= regno && regno < NUM_GREGS;
}

int
getfpregs_supplies (int regno)
{
  return M68K_FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
}

/* Does the current host support the GETREGS request?  */
int have_ptrace_getregs =
#ifdef HAVE_PTRACE_GETREGS
  1
#else
  0
#endif
;



/* Fetching registers directly from the U area, one at a time.  */

/* Fetch one register.  */

static void
fetch_register (struct regcache *regcache, int regno)
{
  struct gdbarch *gdbarch = get_regcache_arch (regcache);
  long regaddr;
  int i;
  char buf[MAX_REGISTER_SIZE];
  int tid;

  /* Overload thread id onto process id.  */
  tid = TIDGET (inferior_ptid);
  if (tid == 0)
    tid = PIDGET (inferior_ptid);	/* no thread id, just use
					   process id.  */

  regaddr = 4 * regmap[regno];
  for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
    {
      errno = 0;
      *(long *) &buf[i] = ptrace (PTRACE_PEEKUSER, tid, regaddr, 0);
      regaddr += sizeof (long);
      if (errno != 0)
	error (_("Couldn't read register %s (#%d): %s."), 
	       gdbarch_register_name (gdbarch, regno),
	       regno, safe_strerror (errno));
    }
  regcache_raw_supply (regcache, regno, buf);
}

/* Fetch register values from the inferior.
   If REGNO is negative, do this for all registers.
   Otherwise, REGNO specifies which register (so we can save time).  */

static void
old_fetch_inferior_registers (struct regcache *regcache, int regno)
{
  if (regno >= 0)
    {
      fetch_register (regcache, regno);
    }
  else
    {
      for (regno = 0;
	   regno < gdbarch_num_regs (get_regcache_arch (regcache));
	   regno++)
	{
	  fetch_register (regcache, regno);
	}
    }
}

/* Store one register.  */

static void
store_register (const struct regcache *regcache, int regno)
{
  struct gdbarch *gdbarch = get_regcache_arch (regcache);
  long regaddr;
  int i;
  int tid;
  char buf[MAX_REGISTER_SIZE];

  /* Overload thread id onto process id.  */
  tid = TIDGET (inferior_ptid);
  if (tid == 0)
    tid = PIDGET (inferior_ptid);	/* no thread id, just use
					   process id.  */

  regaddr = 4 * regmap[regno];

  /* Put the contents of regno into a local buffer.  */
  regcache_raw_collect (regcache, regno, buf);

  /* Store the local buffer into the inferior a chunk at the time.  */
  for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
    {
      errno = 0;
      ptrace (PTRACE_POKEUSER, tid, regaddr, *(long *) &buf[i]);
      regaddr += sizeof (long);
      if (errno != 0)
	error (_("Couldn't write register %s (#%d): %s."),
	       gdbarch_register_name (gdbarch, regno),
	       regno, safe_strerror (errno));
    }
}

/* Store our register values back into the inferior.
   If REGNO is negative, do this for all registers.
   Otherwise, REGNO specifies which register (so we can save time).  */

static void
old_store_inferior_registers (const struct regcache *regcache, int regno)
{
  if (regno >= 0)
    {
      store_register (regcache, regno);
    }
  else
    {
      for (regno = 0;
	   regno < gdbarch_num_regs (get_regcache_arch (regcache));
	   regno++)
	{
	  store_register (regcache, regno);
	}
    }
}

/*  Given a pointer to a general register set in /proc format
   (elf_gregset_t *), unpack the register contents and supply
   them as gdb's idea of the current register values.  */

void
supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
{
  struct gdbarch *gdbarch = get_regcache_arch (regcache);
  const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
  int regi;

  for (regi = M68K_D0_REGNUM;
       regi <= gdbarch_sp_regnum (gdbarch);
       regi++)
    regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
  regcache_raw_supply (regcache, gdbarch_ps_regnum (gdbarch),
		       &regp[PT_SR]);
  regcache_raw_supply (regcache,
		       gdbarch_pc_regnum (gdbarch), &regp[PT_PC]);
}

/* 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 (const struct regcache *regcache,
	      elf_gregset_t *gregsetp, int regno)
{
  elf_greg_t *regp = (elf_greg_t *) gregsetp;
  int i;

  for (i = 0; i < NUM_GREGS; i++)
    if (regno == -1 || regno == i)
      regcache_raw_collect (regcache, i, regp + regmap[i]);
}

#ifdef HAVE_PTRACE_GETREGS

/* Fetch all general-purpose registers from process/thread TID and
   store their values in GDB's register array.  */

static void
fetch_regs (struct regcache *regcache, int tid)
{
  elf_gregset_t regs;

  if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
    {
      if (errno == EIO)
	{
	  /* The kernel we're running on doesn't support the GETREGS
             request.  Reset `have_ptrace_getregs'.  */
	  have_ptrace_getregs = 0;
	  return;
	}

      perror_with_name (_("Couldn't get registers"));
    }

  supply_gregset (regcache, (const elf_gregset_t *) &regs);
}

/* Store all valid general-purpose registers in GDB's register array
   into the process/thread specified by TID.  */

static void
store_regs (const struct regcache *regcache, int tid, int regno)
{
  elf_gregset_t regs;

  if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
    perror_with_name (_("Couldn't get registers"));

  fill_gregset (regcache, &regs, regno);

  if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
    perror_with_name (_("Couldn't write registers"));
}

#else

static void fetch_regs (struct regcache *regcache, int tid)
{
}

static void store_regs (const struct regcache *regcache, int tid, int regno)
{
}

#endif


/* Transfering floating-point registers between GDB, inferiors and cores.  */

/* What is the address of fpN within the floating-point register set F?  */
#define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])

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

void
supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
{
  struct gdbarch *gdbarch = get_regcache_arch (regcache);
  int regi;

  for (regi = gdbarch_fp0_regnum (gdbarch);
       regi < gdbarch_fp0_regnum (gdbarch) + 8; regi++)
    regcache_raw_supply (regcache, regi,
			 FPREG_ADDR (fpregsetp,
				     regi - gdbarch_fp0_regnum (gdbarch)));
  regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
  regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
  regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
}

/* 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 (const struct regcache *regcache,
	       elf_fpregset_t *fpregsetp, int regno)
{
  struct gdbarch *gdbarch = get_regcache_arch (regcache);
  int i;

  /* Fill in the floating-point registers.  */
  for (i = gdbarch_fp0_regnum (gdbarch);
       i < gdbarch_fp0_regnum (gdbarch) + 8; i++)
    if (regno == -1 || regno == i)
      regcache_raw_collect (regcache, i,
			    FPREG_ADDR (fpregsetp,
				        i - gdbarch_fp0_regnum (gdbarch)));

  /* Fill in the floating-point control registers.  */
  for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
    if (regno == -1 || regno == i)
      regcache_raw_collect (regcache, i,
			    &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
}

#ifdef HAVE_PTRACE_GETREGS

/* Fetch all floating-point registers from process/thread TID and store
   thier values in GDB's register array.  */

static void
fetch_fpregs (struct regcache *regcache, int tid)
{
  elf_fpregset_t fpregs;

  if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
    perror_with_name (_("Couldn't get floating point status"));

  supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
}

/* Store all valid floating-point registers in GDB's register array
   into the process/thread specified by TID.  */

static void
store_fpregs (const struct regcache *regcache, int tid, int regno)
{
  elf_fpregset_t fpregs;

  if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
    perror_with_name (_("Couldn't get floating point status"));

  fill_fpregset (regcache, &fpregs, regno);

  if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
    perror_with_name (_("Couldn't write floating point status"));
}

#else

static void fetch_fpregs (struct regcache *regcache, int tid)
{
}

static void store_fpregs (const struct regcache *regcache, int tid, int regno)
{
}

#endif

/* Transferring arbitrary registers between GDB and inferior.  */

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

static void
m68k_linux_fetch_inferior_registers (struct target_ops *ops,
				     struct regcache *regcache, int regno)
{
  int tid;

  /* Use the old method of peeking around in `struct user' if the
     GETREGS request isn't available.  */
  if (! have_ptrace_getregs)
    {
      old_fetch_inferior_registers (regcache, regno);
      return;
    }

  /* GNU/Linux LWP ID's are process ID's.  */
  tid = TIDGET (inferior_ptid);
  if (tid == 0)
    tid = PIDGET (inferior_ptid);	/* Not a threaded program.  */

  /* Use the PTRACE_GETFPXREGS request whenever possible, since it
     transfers more registers in one system call, and we'll cache the
     results.  But remember that fetch_fpxregs can fail, and return
     zero.  */
  if (regno == -1)
    {
      fetch_regs (regcache, tid);

      /* The call above might reset `have_ptrace_getregs'.  */
      if (! have_ptrace_getregs)
	{
	  old_fetch_inferior_registers (regcache, -1);
	  return;
	}

      fetch_fpregs (regcache, tid);
      return;
    }

  if (getregs_supplies (regno))
    {
      fetch_regs (regcache, tid);
      return;
    }

  if (getfpregs_supplies (regno))
    {
      fetch_fpregs (regcache, tid);
      return;
    }

  internal_error (__FILE__, __LINE__,
		  _("Got request for bad register number %d."), regno);
}

/* Store register REGNO back into the child process.  If REGNO is -1,
   do this for all registers (including the floating point and SSE
   registers).  */
static void
m68k_linux_store_inferior_registers (struct target_ops *ops,
				     struct regcache *regcache, int regno)
{
  int tid;

  /* Use the old method of poking around in `struct user' if the
     SETREGS request isn't available.  */
  if (! have_ptrace_getregs)
    {
      old_store_inferior_registers (regcache, regno);
      return;
    }

  /* GNU/Linux LWP ID's are process ID's.  */
  tid = TIDGET (inferior_ptid);
  if (tid == 0)
    tid = PIDGET (inferior_ptid);	/* Not a threaded program.  */

  /* Use the PTRACE_SETFPREGS requests whenever possible, since it
     transfers more registers in one system call.  But remember that
     store_fpregs can fail, and return zero.  */
  if (regno == -1)
    {
      store_regs (regcache, tid, regno);
      store_fpregs (regcache, tid, regno);
      return;
    }

  if (getregs_supplies (regno))
    {
      store_regs (regcache, tid, regno);
      return;
    }

  if (getfpregs_supplies (regno))
    {
      store_fpregs (regcache, tid, regno);
      return;
    }

  internal_error (__FILE__, __LINE__,
		  _("Got request to store bad register number %d."), regno);
}

/* Interpreting register set info found in core files.  */

/* Provide registers to GDB from a core file.

   (We can't use the generic version of this function in
   core-regset.c, because we need to use elf_gregset_t instead of
   gregset_t.)

   CORE_REG_SECT points to an array of bytes, which are the contents
   of a `note' from a core file which BFD thinks might contain
   register contents.  CORE_REG_SIZE is its size.

   WHICH says which register set corelow suspects this is:
     0 --- the general-purpose register set, in elf_gregset_t format
     2 --- the floating-point register set, in elf_fpregset_t format

   REG_ADDR isn't used on GNU/Linux.  */

static void
fetch_core_registers (struct regcache *regcache,
		      char *core_reg_sect, unsigned core_reg_size,
		      int which, CORE_ADDR reg_addr)
{
  elf_gregset_t gregset;
  elf_fpregset_t fpregset;

  switch (which)
    {
    case 0:
      if (core_reg_size != sizeof (gregset))
	warning (_("Wrong size gregset in core file."));
      else
	{
	  memcpy (&gregset, core_reg_sect, sizeof (gregset));
	  supply_gregset (regcache, (const elf_gregset_t *) &gregset);
	}
      break;

    case 2:
      if (core_reg_size != sizeof (fpregset))
	warning (_("Wrong size fpregset in core file."));
      else
	{
	  memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
	  supply_fpregset (regcache, (const elf_fpregset_t *) &fpregset);
	}
      break;

    default:
      /* We've covered all the kinds of registers we know about here,
         so this must be something we wouldn't know what to do with
         anyway.  Just ignore it.  */
      break;
    }
}


/* Register that we are able to handle GNU/Linux ELF core file
   formats.  */

static struct core_fns linux_elf_core_fns =
{
  bfd_target_elf_flavour,		/* core_flavour */
  default_check_format,			/* check_format */
  default_core_sniffer,			/* core_sniffer */
  fetch_core_registers,			/* core_read_registers */
  NULL					/* next */
};

void _initialize_m68k_linux_nat (void);

void
_initialize_m68k_linux_nat (void)
{
  struct target_ops *t;

  /* Fill in the generic GNU/Linux methods.  */
  t = linux_target ();

  /* Add our register access methods.  */
  t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
  t->to_store_registers = m68k_linux_store_inferior_registers;

  /* Register the target.  */
  linux_nat_add_target (t);

  deprecated_add_core_fns (&linux_elf_core_fns);
}