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/* Motorola m68k native support for GNU/Linux.

   Copyright 1996, 1998, 2000, 2001, 2002 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 "frame.h"

#include "inferior.h"

#include "language.h"

#include "gdbcore.h"

#include "regcache.h"

#ifdef USG

#include <sys/types.h>

#endif

#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"

/* This table must line up with REGISTER_NAMES in tm-m68k.h */

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 FP0_REGNUM <= regno && regno <= FPI_REGNUM;

}

/* Does the current host support the GETREGS request?  */

int have_ptrace_getregs =

#ifdef HAVE_PTRACE_GETREGS

  1

#else

#endif

;

/* BLOCKEND is the value of u.u_ar0, and points to the place where GS

   is stored.  */

int

m68k_linux_register_u_addr (int blockend, int regnum)

{

  return (blockend + 4 * regmap[regnum]);

}

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

/* FIXME: This duplicates code from `inptrace.c'.  The problem is that we

   define FETCH_INFERIOR_REGISTERS since we want to use our own versions

   of {fetch,store}_inferior_registers that use the GETREGS request.  This

   means that the code in `infptrace.c' is #ifdef'd out.  But we need to

   fall back on that code when GDB is running on top of a kernel that

   doesn't support the GETREGS request.  */

#ifndef PT_READ_U

#define PT_READ_U PTRACE_PEEKUSR

#endif

#ifndef PT_WRITE_U

#define PT_WRITE_U PTRACE_POKEUSR

#endif

/* Default the type of the ptrace transfer to int.  */

#ifndef PTRACE_XFER_TYPE

#define PTRACE_XFER_TYPE int

#endif

/* Fetch one register.  */

static void

fetch_register (int regno)

{

  /* This isn't really an address.  But ptrace thinks of it as one.  */

  CORE_ADDR regaddr;

  char mess[128];               /* For messages */

  register int i;

  unsigned int offset;          /* Offset of registers within the u area.  */

  char buf[MAX_REGISTER_RAW_SIZE];

  int tid;

  if (CANNOT_FETCH_REGISTER (regno))

    {

      memset (buf, '\0', REGISTER_RAW_SIZE (regno));    /* Supply zeroes */

      supply_register (regno, buf);

      return;

    }

  /* Overload thread id onto process id */

  if ((tid = TIDGET (inferior_ptid)) == 0)

    tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */

  offset = U_REGS_OFFSET;

  regaddr = register_addr (regno, offset);

  for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))

    {

      errno = 0;

      *(PTRACE_XFER_TYPE *) & buf[i] = ptrace (PT_READ_U, tid,

                                               (PTRACE_ARG3_TYPE) regaddr, 0);

      regaddr += sizeof (PTRACE_XFER_TYPE);

      if (errno != 0)

        {

          sprintf (mess, "reading register %s (#%d)",

                   REGISTER_NAME (regno), regno);

          perror_with_name (mess);

        }

    }

  supply_register (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). */

void

old_fetch_inferior_registers (int regno)

{

  if (regno >= 0)

    {

      fetch_register (regno);

    }

  else

    {

      for (regno = 0; regno < NUM_REGS; regno++)

        {

          fetch_register (regno);

        }

    }

}

/* Store one register. */

static void

store_register (int regno)

{

  /* This isn't really an address.  But ptrace thinks of it as one.  */

  CORE_ADDR regaddr;

  char mess[128];               /* For messages */

  register int i;

  unsigned int offset;          /* Offset of registers within the u area.  */

  int tid;

  char *buf = alloca (MAX_REGISTER_RAW_SIZE);

  if (CANNOT_STORE_REGISTER (regno))

    {

      return;

    }

  /* Overload thread id onto process id */

  if ((tid = TIDGET (inferior_ptid)) == 0)

    tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */

  offset = U_REGS_OFFSET;

  regaddr = register_addr (regno, offset);

  /* Put the contents of regno into a local buffer */

  regcache_collect (regno, buf);

  /* Store the local buffer into the inferior a chunk at the time. */

  for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))

    {

      errno = 0;

      ptrace (PT_WRITE_U, tid, (PTRACE_ARG3_TYPE) regaddr,

              *(PTRACE_XFER_TYPE *) (buf + i));

      regaddr += sizeof (PTRACE_XFER_TYPE);

      if (errno != 0)

        {

          sprintf (mess, "writing register %s (#%d)",

                   REGISTER_NAME (regno), regno);

          perror_with_name (mess);

        }

    }

}

/* 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).  */

void

old_store_inferior_registers (int regno)

{

  if (regno >= 0)

    {

      store_register (regno);

    }

  else

    {

      for (regno = 0; regno < NUM_REGS; regno++)

        {

          store_register (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. */

/* Note both m68k-tdep.c and m68klinux-nat.c contain definitions

   for supply_gregset and supply_fpregset. The definitions

   in m68k-tdep.c are valid if USE_PROC_FS is defined. Otherwise,

   the definitions in m68klinux-nat.c will be used. This is a

   bit of a hack. The supply_* routines do not belong in

   *_tdep.c files. But, there are several lynx ports that currently

   depend on these definitions. */

#ifndef USE_PROC_FS

/* Prototypes for supply_gregset etc. */

#include "gregset.h"

void

supply_gregset (elf_gregset_t *gregsetp)

{

  elf_greg_t *regp = (elf_greg_t *) gregsetp;

  int regi;

  for (regi = D0_REGNUM; regi <= SP_REGNUM; regi++)

    supply_register (regi, (char *) &regp[regmap[regi]]);

  supply_register (PS_REGNUM, (char *) &regp[PT_SR]);

  supply_register (PC_REGNUM, (char *) &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 (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_collect (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 (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 (&regs);

}

/* Store all valid general-purpose registers in GDB's register array

   into the process/thread specified by TID.  */

static void

store_regs (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 (&regs, regno);

  if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)

    perror_with_name ("Couldn't write registers");

}

#else

static void fetch_regs (int tid) {}

static void store_regs (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) ((char *) &(f)->fpregs[(n) * 3])

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

   *FPREGSETP.  */

void

supply_fpregset (elf_fpregset_t *fpregsetp)

{

  int regi;

  for (regi = FP0_REGNUM; regi < FPC_REGNUM; regi++)

    supply_register (regi, FPREG_ADDR (fpregsetp, regi - FP0_REGNUM));

  supply_register (FPC_REGNUM, (char *) &fpregsetp->fpcntl[0]);

  supply_register (FPS_REGNUM, (char *) &fpregsetp->fpcntl[1]);

  supply_register (FPI_REGNUM, (char *) &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 (elf_fpregset_t *fpregsetp, int regno)

{

  int i;

  /* Fill in the floating-point registers.  */

  for (i = FP0_REGNUM; i < FP0_REGNUM + 8; i++)

    if (regno == -1 || regno == i)

      regcache_collect (regno, FPREG_ADDR (fpregsetp, regno - FP0_REGNUM));

  /* Fill in the floating-point control registers.  */

  for (i = FPC_REGNUM; i <= FPI_REGNUM; i++)

    if (regno == -1 || regno == i)

      regcache_collect (regno, (char *) &fpregsetp->fpcntl[regno - 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 (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 (&fpregs);

}

/* Store all valid floating-point registers in GDB's register array

   into the process/thread specified by TID.  */

static void

store_fpregs (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 (&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 (int tid) {}

static void store_fpregs (int tid, int regno) {}

#endif

#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).  */

void

fetch_inferior_registers (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 (regno);

      return;

    }

  /* GNU/Linux LWP ID's are process ID's.  */

  if ((tid = TIDGET (inferior_ptid)) == 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 (tid);

      /* The call above might reset `have_ptrace_getregs'.  */

      if (! have_ptrace_getregs)

        {

          old_fetch_inferior_registers (-1);

          return;

        }

      fetch_fpregs (tid);

      return;

    }

  if (getregs_supplies (regno))

    {

      fetch_regs (tid);

      return;

    }

  if (getfpregs_supplies (regno))

    {

      fetch_fpregs (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).  */

void

store_inferior_registers (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 (regno);

      return;

    }

  /* GNU/Linux LWP ID's are process ID's.  */

  if ((tid = TIDGET (inferior_ptid)) == 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 (tid, regno);

      store_fpregs (tid, regno);

      return;

    }

  if (getregs_supplies (regno))

    {

      store_regs (tid, regno);

      return;

    }

  if (getfpregs_supplies (regno))

    {

      store_fpregs (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:

     2 --- the floating-point register set, in elf_fpregset_t format

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

static void

fetch_core_registers (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 (&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 (&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;

    }

}

int

kernel_u_size (void)

{

  return (sizeof (struct user));

}

/* Check whether insn1 and insn2 are parts of a signal trampoline.  */

#define IS_SIGTRAMP(insn1, insn2)                                       \

  (/* addaw #20,sp; moveq #119,d0; trap #0 */                           \

   (insn1 == 0xdefc0014 && insn2 == 0x70774e40)                         \

   /* moveq #119,d0; trap #0 */                                         \

   || insn1 == 0x70774e40)

#define IS_RT_SIGTRAMP(insn1, insn2)                                    \

  (/* movel #173,d0; trap #0 */                                         \

   (insn1 == 0x203c0000 && insn2 == 0x00ad4e40)                         \

   /* moveq #82,d0; notb d0; trap #0 */                                 \

   || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40))

/* Return non-zero if PC points into the signal trampoline.  For the sake

   of m68k_linux_frame_saved_pc we also distinguish between non-RT and RT

   signal trampolines.  */

int

m68k_linux_in_sigtramp (CORE_ADDR pc)

{

  CORE_ADDR sp;

  char buf[12];

  unsigned long insn0, insn1, insn2;

  if (read_memory_nobpt (pc - 4, buf, sizeof (buf)))

    return 0;

  insn1 = extract_unsigned_integer (buf + 4, 4);

  insn2 = extract_unsigned_integer (buf + 8, 4);

  if (IS_SIGTRAMP (insn1, insn2))

    return 1;

  if (IS_RT_SIGTRAMP (insn1, insn2))

    return 2;

  insn0 = extract_unsigned_integer (buf, 4);

  if (IS_SIGTRAMP (insn0, insn1))

    return 1;

  if (IS_RT_SIGTRAMP (insn0, insn1))

    return 2;

  insn0 = (insn0 << 16) | (insn1 >> 16);

  insn1 = (insn1 << 16) | (insn2 >> 16);

  if (IS_SIGTRAMP (insn0, insn1))

    return 1;

  if (IS_RT_SIGTRAMP (insn0, insn1))

    return 2;

  return 0;

}

/* Offset to saved PC in sigcontext, from <asm/sigcontext.h>.  */

#define SIGCONTEXT_PC_OFFSET 26

/* Offset to saved PC in ucontext, from <asm/ucontext.h>.  */

#define UCONTEXT_PC_OFFSET 88

/* Get saved user PC for sigtramp from sigcontext or ucontext.  */

static CORE_ADDR

m68k_linux_sigtramp_saved_pc (struct frame_info *frame)

{

  CORE_ADDR sigcontext_addr;

  char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT];

  int ptrbytes = TARGET_PTR_BIT / TARGET_CHAR_BIT;

  int sigcontext_offs = (2 * TARGET_INT_BIT) / TARGET_CHAR_BIT;

  /* Get sigcontext address, it is the third parameter on the stack.  */

  if (frame->next)

    sigcontext_addr = read_memory_integer (FRAME_ARGS_ADDRESS (frame->next)

                                           + FRAME_ARGS_SKIP

                                           + sigcontext_offs,

                                           ptrbytes);

  else

    sigcontext_addr = read_memory_integer (read_register (SP_REGNUM)

                                           + sigcontext_offs,

                                           ptrbytes);

  /* Don't cause a memory_error when accessing sigcontext in case the

     stack layout has changed or the stack is corrupt.  */

  if (m68k_linux_in_sigtramp (frame->pc) == 2)

    target_read_memory (sigcontext_addr + UCONTEXT_PC_OFFSET, buf, ptrbytes);

  else

    target_read_memory (sigcontext_addr + SIGCONTEXT_PC_OFFSET, buf, ptrbytes);

  return extract_unsigned_integer (buf, ptrbytes);

}

/* Return the saved program counter for FRAME.  */

CORE_ADDR

m68k_linux_frame_saved_pc (struct frame_info *frame)

{

  if (frame->signal_handler_caller)

    return m68k_linux_sigtramp_saved_pc (frame);

  return read_memory_integer (frame->frame + 4, 4);

}

/* 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)

{

  add_core_fns (&linux_elf_core_fns);

}