/* Functions specific to running GDB native on HPPA running GNU/Linux.

   Copyright (C) 2004-2021 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 "gdbcore.h"
#include "regcache.h"
#include "inferior.h"
#include "target.h"
#include "linux-nat.h"
#include "inf-ptrace.h"
#include "gdbarch.h"

#include <sys/procfs.h>
#include "nat/gdb_ptrace.h"
#include <linux/version.h>

#include <asm/ptrace.h>
#include "hppa-linux-offsets.h"

#include "hppa-tdep.h"

class hppa_linux_nat_target final : public linux_nat_target
{
public:
  /* Add our register access methods.  */
  void fetch_registers (struct regcache *, int) override;
  void store_registers (struct regcache *, int) override;
};

static hppa_linux_nat_target the_hppa_linux_nat_target;

/* Prototypes for supply_gregset etc.  */
#include "gregset.h"

/* These must match the order of the register names.

   Some sort of lookup table is needed because the offsets associated
   with the registers are all over the board.  */

static const int u_offsets[] =
  {
    /* general registers */
    -1,
    PT_GR1,
    PT_GR2,
    PT_GR3,
    PT_GR4,
    PT_GR5,
    PT_GR6,
    PT_GR7,
    PT_GR8,
    PT_GR9,
    PT_GR10,
    PT_GR11,
    PT_GR12,
    PT_GR13,
    PT_GR14,
    PT_GR15,
    PT_GR16,
    PT_GR17,
    PT_GR18,
    PT_GR19,
    PT_GR20,
    PT_GR21,
    PT_GR22,
    PT_GR23,
    PT_GR24,
    PT_GR25,
    PT_GR26,
    PT_GR27,
    PT_GR28,
    PT_GR29,
    PT_GR30,
    PT_GR31,

    PT_SAR,
    PT_IAOQ0,
    PT_IASQ0,
    PT_IAOQ1,
    PT_IASQ1,
    -1, /* eiem */
    PT_IIR,
    PT_ISR,
    PT_IOR,
    PT_PSW,
    -1, /* goto */

    PT_SR4,
    PT_SR0,
    PT_SR1,
    PT_SR2,
    PT_SR3,
    PT_SR5,
    PT_SR6,
    PT_SR7,

    -1, /* cr0 */
    -1, /* pid0 */
    -1, /* pid1 */
    -1, /* ccr */
    -1, /* pid2 */
    -1, /* pid3 */
    -1, /* cr24 */
    -1, /* cr25 */
    -1, /* cr26 */
    PT_CR27,
    -1, /* cr28 */
    -1, /* cr29 */
    -1, /* cr30 */

    /* Floating point regs.  */
    PT_FR0,  PT_FR0 + 4,
    PT_FR1,  PT_FR1 + 4,
    PT_FR2,  PT_FR2 + 4,
    PT_FR3,  PT_FR3 + 4,
    PT_FR4,  PT_FR4 + 4,
    PT_FR5,  PT_FR5 + 4,
    PT_FR6,  PT_FR6 + 4,
    PT_FR7,  PT_FR7 + 4,
    PT_FR8,  PT_FR8 + 4,
    PT_FR9,  PT_FR9 + 4,
    PT_FR10, PT_FR10 + 4,
    PT_FR11, PT_FR11 + 4,
    PT_FR12, PT_FR12 + 4,
    PT_FR13, PT_FR13 + 4,
    PT_FR14, PT_FR14 + 4,
    PT_FR15, PT_FR15 + 4,
    PT_FR16, PT_FR16 + 4,
    PT_FR17, PT_FR17 + 4,
    PT_FR18, PT_FR18 + 4,
    PT_FR19, PT_FR19 + 4,
    PT_FR20, PT_FR20 + 4,
    PT_FR21, PT_FR21 + 4,
    PT_FR22, PT_FR22 + 4,
    PT_FR23, PT_FR23 + 4,
    PT_FR24, PT_FR24 + 4,
    PT_FR25, PT_FR25 + 4,
    PT_FR26, PT_FR26 + 4,
    PT_FR27, PT_FR27 + 4,
    PT_FR28, PT_FR28 + 4,
    PT_FR29, PT_FR29 + 4,
    PT_FR30, PT_FR30 + 4,
    PT_FR31, PT_FR31 + 4,
  };

static CORE_ADDR
hppa_linux_register_addr (int regno, CORE_ADDR blockend)
{
  CORE_ADDR addr;

  if ((unsigned) regno >= ARRAY_SIZE (u_offsets))
    error (_("Invalid register number %d."), regno);

  if (u_offsets[regno] == -1)
    addr = 0;
  else
    {
      addr = (CORE_ADDR) u_offsets[regno];
    }

  return addr;
}

/*
 * Registers saved in a coredump:
 * gr0..gr31
 * sr0..sr7
 * iaoq0..iaoq1
 * iasq0..iasq1
 * sar, iir, isr, ior, ipsw
 * cr0, cr24..cr31
 * cr8,9,12,13
 * cr10, cr15
 */
#define GR_REGNUM(_n)	(HPPA_R0_REGNUM+_n)
#define TR_REGNUM(_n)	(HPPA_TR0_REGNUM+_n)
static const int greg_map[] =
  {
    GR_REGNUM(0), GR_REGNUM(1), GR_REGNUM(2), GR_REGNUM(3),
    GR_REGNUM(4), GR_REGNUM(5), GR_REGNUM(6), GR_REGNUM(7),
    GR_REGNUM(8), GR_REGNUM(9), GR_REGNUM(10), GR_REGNUM(11),
    GR_REGNUM(12), GR_REGNUM(13), GR_REGNUM(14), GR_REGNUM(15),
    GR_REGNUM(16), GR_REGNUM(17), GR_REGNUM(18), GR_REGNUM(19),
    GR_REGNUM(20), GR_REGNUM(21), GR_REGNUM(22), GR_REGNUM(23),
    GR_REGNUM(24), GR_REGNUM(25), GR_REGNUM(26), GR_REGNUM(27),
    GR_REGNUM(28), GR_REGNUM(29), GR_REGNUM(30), GR_REGNUM(31),

    HPPA_SR4_REGNUM+1, HPPA_SR4_REGNUM+2, HPPA_SR4_REGNUM+3, HPPA_SR4_REGNUM+4,
    HPPA_SR4_REGNUM, HPPA_SR4_REGNUM+5, HPPA_SR4_REGNUM+6, HPPA_SR4_REGNUM+7,

    HPPA_PCOQ_HEAD_REGNUM, HPPA_PCOQ_TAIL_REGNUM,
    HPPA_PCSQ_HEAD_REGNUM, HPPA_PCSQ_TAIL_REGNUM,

    HPPA_SAR_REGNUM, HPPA_IIR_REGNUM, HPPA_ISR_REGNUM, HPPA_IOR_REGNUM,
    HPPA_IPSW_REGNUM, HPPA_RCR_REGNUM,

    TR_REGNUM(0), TR_REGNUM(1), TR_REGNUM(2), TR_REGNUM(3),
    TR_REGNUM(4), TR_REGNUM(5), TR_REGNUM(6), TR_REGNUM(7),

    HPPA_PID0_REGNUM, HPPA_PID1_REGNUM, HPPA_PID2_REGNUM, HPPA_PID3_REGNUM,
    HPPA_CCR_REGNUM, HPPA_EIEM_REGNUM,
  };


/* Fetch one register.  */

static void
fetch_register (struct regcache *regcache, int regno)
{
  struct gdbarch *gdbarch = regcache->arch ();
  pid_t tid;
  int val;

  if (gdbarch_cannot_fetch_register (gdbarch, regno))
    {
      regcache->raw_supply (regno, NULL);
      return;
    }

  tid = get_ptrace_pid (regcache->ptid ());

  errno = 0;
  val = ptrace (PTRACE_PEEKUSER, tid, hppa_linux_register_addr (regno, 0), 0);
  if (errno != 0)
    error (_("Couldn't read register %s (#%d): %s."), 
	   gdbarch_register_name (gdbarch, regno),
	   regno, safe_strerror (errno));

  regcache->raw_supply (regno, &val);
}

/* Store one register.  */

static void
store_register (const struct regcache *regcache, int regno)
{
  struct gdbarch *gdbarch = regcache->arch ();
  pid_t tid;
  int val;

  if (gdbarch_cannot_store_register (gdbarch, regno))
    return;

  tid = get_ptrace_pid (regcache->ptid ());

  errno = 0;
  regcache->raw_collect (regno, &val);
  ptrace (PTRACE_POKEUSER, tid, hppa_linux_register_addr (regno, 0), val);
  if (errno != 0)
    error (_("Couldn't write register %s (#%d): %s."),
	   gdbarch_register_name (gdbarch, regno),
	   regno, safe_strerror (errno));
}

/* Fetch registers from the child process.  Fetch all registers if
   regno == -1, otherwise fetch all general registers or all floating
   point registers depending upon the value of regno.  */

void
hppa_linux_nat_target::fetch_registers (struct regcache *regcache, int regno)
{
  if (-1 == regno)
    {
      for (regno = 0;
	   regno < gdbarch_num_regs (regcache->arch ());
	   regno++)
	fetch_register (regcache, regno);
    }
  else 
    {
      fetch_register (regcache, regno);
    }
}

/* Store registers back into the inferior.  Store all registers if
   regno == -1, otherwise store all general registers or all floating
   point registers depending upon the value of regno.  */

void
hppa_linux_nat_target::store_registers (struct regcache *regcache, int regno)
{
  if (-1 == regno)
    {
      for (regno = 0;
	   regno < gdbarch_num_regs (regcache->arch ());
	   regno++)
	store_register (regcache, regno);
    }
  else
    {
      store_register (regcache, regno);
    }
}

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

void
supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregsetp)
{
  int i;
  const greg_t *regp = (const elf_greg_t *) gregsetp;

  for (i = 0; i < sizeof (greg_map) / sizeof (greg_map[0]); i++, regp++)
    {
      int regno = greg_map[i];
      regcache->raw_supply (regno, regp);
    }
}

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

void
fill_gregset (const struct regcache *regcache,
	      gdb_gregset_t *gregsetp, int regno)
{
  int i;

  for (i = 0; i < sizeof (greg_map) / sizeof (greg_map[0]); i++)
    {
      int mregno = greg_map[i];

      if (regno == -1 || regno == mregno)
	regcache->raw_collect (mregno, &(*gregsetp)[i]);
    }
}

/*  Given a pointer to a floating point register set in /proc format
   (fpregset_t *), unpack the register contents and supply them as gdb's
   idea of the current floating point register values.  */

void
supply_fpregset (struct regcache *regcache, const gdb_fpregset_t *fpregsetp)
{
  int regi;
  const char *from;

  for (regi = 0; regi <= 31; regi++)
    {
      from = (const char *) &((*fpregsetp)[regi]);
      regcache->raw_supply (2*regi + HPPA_FP0_REGNUM, from);
      regcache->raw_supply (2*regi + HPPA_FP0_REGNUM + 1, from + 4);
    }
}

/*  Given a pointer to a floating point register set in /proc format
   (fpregset_t *), update the register specified by REGNO from gdb's idea
   of the current floating point register set.  If REGNO is -1, update
   them all.  */

void
fill_fpregset (const struct regcache *regcache,
	       gdb_fpregset_t *fpregsetp, int regno)
{
  int i;

  for (i = HPPA_FP0_REGNUM; i < HPPA_FP0_REGNUM + 32 * 2; i++)
   {
      /* Gross.  fpregset_t is double, registers[x] has single
	 precision reg.  */
      char *to = (char *) &((*fpregsetp)[(i - HPPA_FP0_REGNUM) / 2]);
      if ((i - HPPA_FP0_REGNUM) & 1)
	to += 4;
      regcache->raw_collect (i, to);
   }
}

void _initialize_hppa_linux_nat ();
void
_initialize_hppa_linux_nat ()
{
  /* Register the target.  */
  linux_target = &the_hppa_linux_nat_target;
  add_inf_child_target (&the_hppa_linux_nat_target);
}