/* GNU/Linux S/390 specific low level interface, for the remote server
   for GDB.
   Copyright (C) 2001, 2002, 2005, 2006, 2007, 2008
   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/>.  */

/* This file is used for both 31-bit and 64-bit S/390 systems.  */

#include "server.h"
#include "linux-low.h"

#include <asm/ptrace.h>

/* Defined in auto-generated file reg-s390.c.  */
void init_registers_s390 (void);
/* Defined in auto-generated file reg-s390x.c.  */
void init_registers_s390x (void);


#define s390_num_regs 51

static int s390_regmap[] = {
  PT_PSWMASK, PT_PSWADDR,

  PT_GPR0, PT_GPR1, PT_GPR2, PT_GPR3,
  PT_GPR4, PT_GPR5, PT_GPR6, PT_GPR7,
  PT_GPR8, PT_GPR9, PT_GPR10, PT_GPR11,
  PT_GPR12, PT_GPR13, PT_GPR14, PT_GPR15,

  PT_ACR0, PT_ACR1, PT_ACR2, PT_ACR3,
  PT_ACR4, PT_ACR5, PT_ACR6, PT_ACR7,
  PT_ACR8, PT_ACR9, PT_ACR10, PT_ACR11,
  PT_ACR12, PT_ACR13, PT_ACR14, PT_ACR15,

  PT_FPC,

#ifndef __s390x__
  PT_FPR0_HI, PT_FPR1_HI, PT_FPR2_HI, PT_FPR3_HI,
  PT_FPR4_HI, PT_FPR5_HI, PT_FPR6_HI, PT_FPR7_HI,
  PT_FPR8_HI, PT_FPR9_HI, PT_FPR10_HI, PT_FPR11_HI,
  PT_FPR12_HI, PT_FPR13_HI, PT_FPR14_HI, PT_FPR15_HI,
#else
  PT_FPR0, PT_FPR1, PT_FPR2, PT_FPR3,
  PT_FPR4, PT_FPR5, PT_FPR6, PT_FPR7,
  PT_FPR8, PT_FPR9, PT_FPR10, PT_FPR11,
  PT_FPR12, PT_FPR13, PT_FPR14, PT_FPR15,
#endif
};

static int
s390_cannot_fetch_register (int regno)
{
  if (s390_regmap[regno] == -1)
    return 1;

  return 0;
}

static int
s390_cannot_store_register (int regno)
{
  if (s390_regmap[regno] == -1)
    return 1;

  return 0;
}

static void
s390_collect_ptrace_register (int regno, char *buf)
{
  int size = register_size (regno);
  if (size < sizeof (long))
    {
      memset (buf, 0, sizeof (long));

      if (regno == find_regno ("pswa")
	  || (regno >= find_regno ("r0") && regno <= find_regno ("r15")))
	collect_register (regno, buf + sizeof (long) - size);
      else
	collect_register (regno, buf);

      /* When debugging a 32-bit inferior on a 64-bit host, make sure
	 the 31-bit addressing mode bit is set in the PSW mask.  */
      if (regno == find_regno ("pswm"))
	buf[size] |= 0x80;
    }
  else
    collect_register (regno, buf);
}

static void
s390_supply_ptrace_register (int regno, const char *buf)
{
  int size = register_size (regno);
  if (size < sizeof (long))
    {
      if (regno == find_regno ("pswa")
	  || (regno >= find_regno ("r0") && regno <= find_regno ("r15")))
	supply_register (regno, buf + sizeof (long) - size);
      else
	supply_register (regno, buf);
    }
  else
    supply_register (regno, buf);
}

/* Provide only a fill function for the general register set.  ps_lgetregs
   will use this for NPTL support.  */

static void s390_fill_gregset (void *buf)
{
  int i;

  for (i = 0; i < 34; i++)
    s390_collect_ptrace_register (i, (char *) buf + s390_regmap[i]);
}

struct regset_info target_regsets[] = {
  { 0, 0, 0, GENERAL_REGS, s390_fill_gregset, NULL },
  { 0, 0, -1, -1, NULL, NULL }
};


static const unsigned char s390_breakpoint[] = { 0, 1 };
#define s390_breakpoint_len 2

static CORE_ADDR
s390_get_pc ()
{
  if (register_size (0) == 4)
    {
      unsigned int pc;
      collect_register_by_name ("pswa", &pc);
#ifndef __s390x__
      pc &= 0x7fffffff;
#endif
      return pc;
    }
  else
    {
      unsigned long pc;
      collect_register_by_name ("pswa", &pc);
      return pc;
    }
}

static void
s390_set_pc (CORE_ADDR newpc)
{
  if (register_size (0) == 4)
    {
      unsigned int pc = newpc;
#ifndef __s390x__
      pc |= 0x80000000;
#endif
      supply_register_by_name ("pswa", &pc);
    }
  else
    {
      unsigned long pc = newpc;
      supply_register_by_name ("pswa", &pc);
    }
}


static void
s390_arch_setup (void)
{
  /* Assume 31-bit inferior process.  */
  init_registers_s390 ();

  /* On a 64-bit host, check the low bit of the (31-bit) PSWM
     -- if this is one, we actually have a 64-bit inferior.  */
#ifdef __s390x__
  {
    unsigned int pswm;
    collect_register_by_name ("pswm", &pswm);
    if (pswm & 1)
      init_registers_s390x ();
  }
#endif
}


static int
s390_breakpoint_at (CORE_ADDR pc)
{
  unsigned char c[s390_breakpoint_len];
  read_inferior_memory (pc, c, s390_breakpoint_len);
  return memcmp (c, s390_breakpoint, s390_breakpoint_len) == 0;
}


struct linux_target_ops the_low_target = {
  s390_arch_setup,
  s390_num_regs,
  s390_regmap,
  s390_cannot_fetch_register,
  s390_cannot_store_register,
  s390_get_pc,
  s390_set_pc,
  s390_breakpoint,
  s390_breakpoint_len,
  NULL,
  s390_breakpoint_len,
  s390_breakpoint_at,
  NULL,
  NULL,
  NULL,
  NULL,
  s390_collect_ptrace_register,
  s390_supply_ptrace_register,
};