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/* Cell SPU GNU/Linux multi-architecture debugging support.

   Copyright (C) 2009, 2010 Free Software Foundation, Inc.

   Contributed by Ulrich Weigand <uweigand@de.ibm.com>.

   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 "gdbcmd.h"

#include "gdb_string.h"

#include "gdb_assert.h"

#include "arch-utils.h"

#include "observer.h"

#include "inferior.h"

#include "regcache.h"

#include "symfile.h"

#include "objfiles.h"

#include "solib.h"

#include "solist.h"

#include "ppc-tdep.h"

#include "ppc-linux-tdep.h"

#include "spu-tdep.h"

/* This module's target vector.  */

static struct target_ops spu_ops;

/* Number of SPE objects loaded into the current inferior.  */

static int spu_nr_solib;

/* Stand-alone SPE executable?  */

#define spu_standalone_p() \

  (symfile_objfile && symfile_objfile->obfd \

   && bfd_get_arch (symfile_objfile->obfd) == bfd_arch_spu)

/* PPU side system calls.  */

#define INSTR_SC        0x44000002

#define NR_spu_run      0x0116

/* If the PPU thread is currently stopped on a spu_run system call,

   return to FD and ADDR the file handle and NPC parameter address

   used with the system call.  Return non-zero if successful.  */

static int

parse_spufs_run (ptid_t ptid, int *fd, CORE_ADDR *addr)

{

  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);

  struct gdbarch_tdep *tdep;

  struct regcache *regcache;

  char buf[4];

  CORE_ADDR pc;

  ULONGEST regval;

  /* If we're not on PPU, there's nothing to detect.  */

  if (gdbarch_bfd_arch_info (target_gdbarch)->arch != bfd_arch_powerpc)

    return 0;

  /* Get PPU-side registers.  */

  regcache = get_thread_arch_regcache (ptid, target_gdbarch);

  tdep = gdbarch_tdep (target_gdbarch);

  /* Fetch instruction preceding current NIP.  */

  if (target_read_memory (regcache_read_pc (regcache) - 4, buf, 4) != 0)

    return 0;

  /* It should be a "sc" instruction.  */

  if (extract_unsigned_integer (buf, 4, byte_order) != INSTR_SC)

    return 0;

  /* System call number should be NR_spu_run.  */

  regcache_cooked_read_unsigned (regcache, tdep->ppc_gp0_regnum, &regval);

  if (regval != NR_spu_run)

    return 0;

  /* Register 3 contains fd, register 4 the NPC param pointer.  */

  regcache_cooked_read_unsigned (regcache, PPC_ORIG_R3_REGNUM, &regval);

  *fd = (int) regval;

  regcache_cooked_read_unsigned (regcache, tdep->ppc_gp0_regnum + 4, &regval);

  *addr = (CORE_ADDR) regval;

  return 1;

}

/* Find gdbarch for SPU context SPUFS_FD.  */

static struct gdbarch *

spu_gdbarch (int spufs_fd)

{

  struct gdbarch_info info;

  gdbarch_info_init (&info);

  info.bfd_arch_info = bfd_lookup_arch (bfd_arch_spu, bfd_mach_spu);

  info.byte_order = BFD_ENDIAN_BIG;

  info.osabi = GDB_OSABI_LINUX;

  info.tdep_info = (void *) &spufs_fd;

  return gdbarch_find_by_info (info);

}

/* Override the to_thread_architecture routine.  */

static struct gdbarch *

spu_thread_architecture (struct target_ops *ops, ptid_t ptid)

{

  int spufs_fd;

  CORE_ADDR spufs_addr;

  if (parse_spufs_run (ptid, &spufs_fd, &spufs_addr))

    return spu_gdbarch (spufs_fd);

  return target_gdbarch;

}

/* Override the to_region_ok_for_hw_watchpoint routine.  */

static int

spu_region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)

{

  struct target_ops *ops_beneath = find_target_beneath (&spu_ops);

  while (ops_beneath && !ops_beneath->to_region_ok_for_hw_watchpoint)

    ops_beneath = find_target_beneath (ops_beneath);

  /* We cannot watch SPU local store.  */

  if (SPUADDR_SPU (addr) != -1)

    return 0;

  if (ops_beneath)

    return ops_beneath->to_region_ok_for_hw_watchpoint (addr, len);

  return 0;

}

/* Override the to_fetch_registers routine.  */

static void

spu_fetch_registers (struct target_ops *ops,

                     struct regcache *regcache, int regno)

{

  struct gdbarch *gdbarch = get_regcache_arch (regcache);

  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);

  struct target_ops *ops_beneath = find_target_beneath (ops);

  int spufs_fd;

  CORE_ADDR spufs_addr;

  /* This version applies only if we're currently in spu_run.  */

  if (gdbarch_bfd_arch_info (gdbarch)->arch != bfd_arch_spu)

    {

      while (ops_beneath && !ops_beneath->to_fetch_registers)

        ops_beneath = find_target_beneath (ops_beneath);

      gdb_assert (ops_beneath);

      ops_beneath->to_fetch_registers (ops_beneath, regcache, regno);

      return;

    }

  /* We must be stopped on a spu_run system call.  */

  if (!parse_spufs_run (inferior_ptid, &spufs_fd, &spufs_addr))

    return;

  /* The ID register holds the spufs file handle.  */

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

    {

      char buf[4];

      store_unsigned_integer (buf, 4, byte_order, spufs_fd);

      regcache_raw_supply (regcache, SPU_ID_REGNUM, buf);

    }

  /* The NPC register is found in PPC memory at SPUFS_ADDR.  */

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

    {

      char buf[4];

      if (target_read (ops_beneath, TARGET_OBJECT_MEMORY, NULL,

                       buf, spufs_addr, sizeof buf) == sizeof buf)

        regcache_raw_supply (regcache, SPU_PC_REGNUM, buf);

    }

  /* The GPRs are found in the "regs" spufs file.  */

  if (regno == -1 || (regno >= 0 && regno < SPU_NUM_GPRS))

    {

      char buf[16 * SPU_NUM_GPRS], annex[32];

      int i;

      xsnprintf (annex, sizeof annex, "%d/regs", spufs_fd);

      if (target_read (ops_beneath, TARGET_OBJECT_SPU, annex,

                       buf, 0, sizeof buf) == sizeof buf)

        for (i = 0; i < SPU_NUM_GPRS; i++)

          regcache_raw_supply (regcache, i, buf + i*16);

    }

}

/* Override the to_store_registers routine.  */

static void

spu_store_registers (struct target_ops *ops,

                     struct regcache *regcache, int regno)

{

  struct gdbarch *gdbarch = get_regcache_arch (regcache);

  struct target_ops *ops_beneath = find_target_beneath (ops);

  int spufs_fd;

  CORE_ADDR spufs_addr;

  /* This version applies only if we're currently in spu_run.  */

  if (gdbarch_bfd_arch_info (gdbarch)->arch != bfd_arch_spu)

    {

      while (ops_beneath && !ops_beneath->to_fetch_registers)

        ops_beneath = find_target_beneath (ops_beneath);

      gdb_assert (ops_beneath);

      ops_beneath->to_store_registers (ops_beneath, regcache, regno);

      return;

    }

  /* We must be stopped on a spu_run system call.  */

  if (!parse_spufs_run (inferior_ptid, &spufs_fd, &spufs_addr))

    return;

  /* The NPC register is found in PPC memory at SPUFS_ADDR.  */

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

    {

      char buf[4];

      regcache_raw_collect (regcache, SPU_PC_REGNUM, buf);

      target_write (ops_beneath, TARGET_OBJECT_MEMORY, NULL,

                    buf, spufs_addr, sizeof buf);

    }

  /* The GPRs are found in the "regs" spufs file.  */

  if (regno == -1 || (regno >= 0 && regno < SPU_NUM_GPRS))

    {

      char buf[16 * SPU_NUM_GPRS], annex[32];

      int i;

      for (i = 0; i < SPU_NUM_GPRS; i++)

        regcache_raw_collect (regcache, i, buf + i*16);

      xsnprintf (annex, sizeof annex, "%d/regs", spufs_fd);

      target_write (ops_beneath, TARGET_OBJECT_SPU, annex,

                    buf, 0, sizeof buf);

    }

}

/* Override the to_xfer_partial routine.  */

static LONGEST

spu_xfer_partial (struct target_ops *ops, enum target_object object,

                  const char *annex, gdb_byte *readbuf,

                  const gdb_byte *writebuf, ULONGEST offset, LONGEST len)

{

  struct target_ops *ops_beneath = find_target_beneath (ops);

  while (ops_beneath && !ops_beneath->to_xfer_partial)

    ops_beneath = find_target_beneath (ops_beneath);

  gdb_assert (ops_beneath);

  /* Use the "mem" spufs file to access SPU local store.  */

  if (object == TARGET_OBJECT_MEMORY)

    {

      int fd = SPUADDR_SPU (offset);

      CORE_ADDR addr = SPUADDR_ADDR (offset);

      char mem_annex[32];

      if (fd >= 0 && addr < SPU_LS_SIZE)

        {

          xsnprintf (mem_annex, sizeof mem_annex, "%d/mem", fd);

          return ops_beneath->to_xfer_partial (ops_beneath, TARGET_OBJECT_SPU,

                                               mem_annex, readbuf, writebuf,

                                               addr, len);

        }

    }

  return ops_beneath->to_xfer_partial (ops_beneath, object, annex,

                                       readbuf, writebuf, offset, len);

}

/* Override the to_search_memory routine.  */

static int

spu_search_memory (struct target_ops* ops,

                   CORE_ADDR start_addr, ULONGEST search_space_len,

                   const gdb_byte *pattern, ULONGEST pattern_len,

                   CORE_ADDR *found_addrp)

{

  struct target_ops *ops_beneath = find_target_beneath (ops);

  while (ops_beneath && !ops_beneath->to_search_memory)

    ops_beneath = find_target_beneath (ops_beneath);

  /* For SPU local store, always fall back to the simple method.  Likewise

     if we do not have any target-specific special implementation.  */

  if (!ops_beneath || SPUADDR_SPU (start_addr) >= 0)

    return simple_search_memory (ops,

                                 start_addr, search_space_len,

                                 pattern, pattern_len, found_addrp);

  return ops_beneath->to_search_memory (ops_beneath,

                                        start_addr, search_space_len,

                                        pattern, pattern_len, found_addrp);

}

/* Push and pop the SPU multi-architecture support target.  */

static void

spu_multiarch_activate (void)

{

  /* If GDB was configured without SPU architecture support,

     we cannot install SPU multi-architecture support either.  */

  if (spu_gdbarch (-1) == NULL)

    return;

  push_target (&spu_ops);

  /* Make sure the thread architecture is re-evaluated.  */

  registers_changed ();

}

static void

spu_multiarch_deactivate (void)

{

  unpush_target (&spu_ops);

  /* Make sure the thread architecture is re-evaluated.  */

  registers_changed ();

}

static void

spu_multiarch_inferior_created (struct target_ops *ops, int from_tty)

{

  if (spu_standalone_p ())

    spu_multiarch_activate ();

}

static void

spu_multiarch_solib_loaded (struct so_list *so)

{

  if (!spu_standalone_p ())

    if (so->abfd && bfd_get_arch (so->abfd) == bfd_arch_spu)

      if (spu_nr_solib++ == 0)

        spu_multiarch_activate ();

}

static void

spu_multiarch_solib_unloaded (struct so_list *so)

{

  if (!spu_standalone_p ())

    if (so->abfd && bfd_get_arch (so->abfd) == bfd_arch_spu)

      if (--spu_nr_solib == 0)

        spu_multiarch_deactivate ();

}

static void

spu_mourn_inferior (struct target_ops *ops)

{

  struct target_ops *ops_beneath = find_target_beneath (ops);

  while (ops_beneath && !ops_beneath->to_mourn_inferior)

    ops_beneath = find_target_beneath (ops_beneath);

  gdb_assert (ops_beneath);

  ops_beneath->to_mourn_inferior (ops_beneath);

  spu_multiarch_deactivate ();

}

/* Initialize the SPU multi-architecture support target.  */

static void

init_spu_ops (void)

{

  spu_ops.to_shortname = "spu";

  spu_ops.to_longname = "SPU multi-architecture support.";

  spu_ops.to_doc = "SPU multi-architecture support.";

  spu_ops.to_mourn_inferior = spu_mourn_inferior;

  spu_ops.to_fetch_registers = spu_fetch_registers;

  spu_ops.to_store_registers = spu_store_registers;

  spu_ops.to_xfer_partial = spu_xfer_partial;

  spu_ops.to_search_memory = spu_search_memory;

  spu_ops.to_region_ok_for_hw_watchpoint = spu_region_ok_for_hw_watchpoint;

  spu_ops.to_thread_architecture = spu_thread_architecture;

  spu_ops.to_stratum = arch_stratum;

  spu_ops.to_magic = OPS_MAGIC;

}

void

_initialize_spu_multiarch (void)

{

  /* Install ourselves on the target stack.  */

  init_spu_ops ();

  add_target (&spu_ops);

  /* Install observers to watch for SPU objects.  */

  observer_attach_inferior_created (spu_multiarch_inferior_created);

  observer_attach_solib_loaded (spu_multiarch_solib_loaded);

  observer_attach_solib_unloaded (spu_multiarch_solib_unloaded);

}