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/* Low level interface to SPUs, for the remote server for GDB.

   Copyright (C) 2006, 2007, 2008 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 "server.h"

#include <sys/wait.h>

#include <stdio.h>

#include <sys/ptrace.h>

#include <fcntl.h>

#include <string.h>

#include <stdlib.h>

#include <unistd.h>

#include <errno.h>

#include <sys/syscall.h>

/* Some older glibc versions do not define this.  */

#ifndef __WNOTHREAD

#define __WNOTHREAD     0x20000000      /* Don't wait on children of other

                                           threads in this group */

#endif

#define PTRACE_TYPE_RET long

#define PTRACE_TYPE_ARG3 long

/* Number of registers.  */

#define SPU_NUM_REGS         130

#define SPU_NUM_CORE_REGS    128

/* Special registers.  */

#define SPU_ID_REGNUM        128

#define SPU_PC_REGNUM        129

/* PPU side system calls.  */

#define INSTR_SC        0x44000002

#define NR_spu_run      0x0116

/* Get current thread ID (Linux task ID).  */

#define current_tid ((struct inferior_list_entry *)current_inferior)->id

/* These are used in remote-utils.c.  */

int using_threads = 0;

/* Fetch PPU register REGNO.  */

static CORE_ADDR

fetch_ppc_register (int regno)

{

  PTRACE_TYPE_RET res;

  int tid = current_tid;

#ifndef __powerpc64__

  /* If running as a 32-bit process on a 64-bit system, we attempt

     to get the full 64-bit register content of the target process.

     If the PPC special ptrace call fails, we're on a 32-bit system;

     just fall through to the regular ptrace call in that case.  */

  {

    char buf[8];

    errno = 0;

    ptrace (PPC_PTRACE_PEEKUSR_3264, tid,

            (PTRACE_TYPE_ARG3) (regno * 8), buf);

    if (errno == 0)

      ptrace (PPC_PTRACE_PEEKUSR_3264, tid,

              (PTRACE_TYPE_ARG3) (regno * 8 + 4), buf + 4);

    if (errno == 0)

      return (CORE_ADDR) *(unsigned long long *)buf;

  }

#endif

  errno = 0;

  res = ptrace (PT_READ_U, tid,

                (PTRACE_TYPE_ARG3) (regno * sizeof (PTRACE_TYPE_RET)), 0);

  if (errno != 0)

    {

      char mess[128];

      sprintf (mess, "reading PPC register #%d", regno);

      perror_with_name (mess);

    }

  return (CORE_ADDR) (unsigned long) res;

}

/* Fetch WORD from PPU memory at (aligned) MEMADDR in thread TID.  */

static int

fetch_ppc_memory_1 (int tid, CORE_ADDR memaddr, PTRACE_TYPE_RET *word)

{

  errno = 0;

#ifndef __powerpc64__

  if (memaddr >> 32)

    {

      unsigned long long addr_8 = (unsigned long long) memaddr;

      ptrace (PPC_PTRACE_PEEKTEXT_3264, tid, (PTRACE_TYPE_ARG3) &addr_8, word);

    }

  else

#endif

    *word = ptrace (PT_READ_I, tid, (PTRACE_TYPE_ARG3) (size_t) memaddr, 0);

  return errno;

}

/* Store WORD into PPU memory at (aligned) MEMADDR in thread TID.  */

static int

store_ppc_memory_1 (int tid, CORE_ADDR memaddr, PTRACE_TYPE_RET word)

{

  errno = 0;

#ifndef __powerpc64__

  if (memaddr >> 32)

    {

      unsigned long long addr_8 = (unsigned long long) memaddr;

      ptrace (PPC_PTRACE_POKEDATA_3264, tid, (PTRACE_TYPE_ARG3) &addr_8, word);

    }

  else

#endif

    ptrace (PT_WRITE_D, tid, (PTRACE_TYPE_ARG3) (size_t) memaddr, word);

  return errno;

}

/* Fetch LEN bytes of PPU memory at MEMADDR to MYADDR.  */

static int

fetch_ppc_memory (CORE_ADDR memaddr, char *myaddr, int len)

{

  int i, ret;

  CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_TYPE_RET);

  int count = ((((memaddr + len) - addr) + sizeof (PTRACE_TYPE_RET) - 1)

               / sizeof (PTRACE_TYPE_RET));

  PTRACE_TYPE_RET *buffer;

  int tid = current_tid;

  buffer = (PTRACE_TYPE_RET *) alloca (count * sizeof (PTRACE_TYPE_RET));

  for (i = 0; i < count; i++, addr += sizeof (PTRACE_TYPE_RET))

    if ((ret = fetch_ppc_memory_1 (tid, addr, &buffer[i])) != 0)

      return ret;

  memcpy (myaddr,

          (char *) buffer + (memaddr & (sizeof (PTRACE_TYPE_RET) - 1)),

          len);

  return 0;

}

/* Store LEN bytes from MYADDR to PPU memory at MEMADDR.  */

static int

store_ppc_memory (CORE_ADDR memaddr, char *myaddr, int len)

{

  int i, ret;

  CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_TYPE_RET);

  int count = ((((memaddr + len) - addr) + sizeof (PTRACE_TYPE_RET) - 1)

               / sizeof (PTRACE_TYPE_RET));

  PTRACE_TYPE_RET *buffer;

  int tid = current_tid;

  buffer = (PTRACE_TYPE_RET *) alloca (count * sizeof (PTRACE_TYPE_RET));

  if (addr != memaddr || len < (int) sizeof (PTRACE_TYPE_RET))

    if ((ret = fetch_ppc_memory_1 (tid, addr, &buffer[0])) != 0)

      return ret;

  if (count > 1)

    if ((ret = fetch_ppc_memory_1 (tid, addr + (count - 1)

                                               * sizeof (PTRACE_TYPE_RET),

                                   &buffer[count - 1])) != 0)

      return ret;

  memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_TYPE_RET) - 1)),

          myaddr, len);

  for (i = 0; i < count; i++, addr += sizeof (PTRACE_TYPE_RET))

    if ((ret = store_ppc_memory_1 (tid, addr, buffer[i])) != 0)

      return ret;

  return 0;

}

/* 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 (int *fd, CORE_ADDR *addr)

{

  char buf[4];

  CORE_ADDR pc = fetch_ppc_register (32);  /* nip */

  /* Fetch instruction preceding current NIP.  */

  if (fetch_ppc_memory (pc-4, buf, 4) != 0)

    return 0;

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

  if (*(unsigned int *)buf != INSTR_SC)

    return 0;

  /* System call number should be NR_spu_run.  */

  if (fetch_ppc_register (0) != NR_spu_run)

    return 0;

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

  *fd = fetch_ppc_register (34);  /* orig_gpr3 */

  *addr = fetch_ppc_register (4);

  return 1;

}

/* Copy LEN bytes at OFFSET in spufs file ANNEX into/from READBUF or WRITEBUF,

   using the /proc file system.  */

static int

spu_proc_xfer_spu (const char *annex, unsigned char *readbuf,

                   const unsigned char *writebuf,

                   CORE_ADDR offset, int len)

{

  char buf[128];

  int fd = 0;

  int ret = -1;

  if (!annex)

    return 0;

  sprintf (buf, "/proc/%ld/fd/%s", current_tid, annex);

  fd = open (buf, writebuf? O_WRONLY : O_RDONLY);

  if (fd <= 0)

    return -1;

  if (offset != 0

      && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)

    {

      close (fd);

      return 0;

    }

  if (writebuf)

    ret = write (fd, writebuf, (size_t) len);

  else if (readbuf)

    ret = read (fd, readbuf, (size_t) len);

  close (fd);

  return ret;

}

/* Start an inferior process and returns its pid.

   ALLARGS is a vector of program-name and args. */

static int

spu_create_inferior (char *program, char **allargs)

{

  int pid;

  pid = fork ();

  if (pid < 0)

    perror_with_name ("fork");

  if (pid == 0)

    {

      ptrace (PTRACE_TRACEME, 0, 0, 0);

      setpgid (0, 0);

      execv (program, allargs);

      if (errno == ENOENT)

        execvp (program, allargs);

      fprintf (stderr, "Cannot exec %s: %s.\n", program,

               strerror (errno));

      fflush (stderr);

      _exit (0177);

    }

  add_thread (pid, NULL, pid);

  return pid;

}

/* Attach to an inferior process.  */

int

spu_attach (unsigned long  pid)

{

  if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0)

    {

      fprintf (stderr, "Cannot attach to process %ld: %s (%d)\n", pid,

               strerror (errno), errno);

      fflush (stderr);

      _exit (0177);

    }

  add_thread (pid, NULL, pid);

  return 0;

}

/* Kill the inferior process.  */

static void

spu_kill (void)

{

  ptrace (PTRACE_KILL, current_tid, 0, 0);

}

/* Detach from inferior process.  */

static int

spu_detach (void)

{

  ptrace (PTRACE_DETACH, current_tid, 0, 0);

  return 0;

}

static void

spu_join (void)

{

  int status, ret;

  do {

    ret = waitpid (current_tid, &status, 0);

    if (WIFEXITED (status) || WIFSIGNALED (status))

      break;

  } while (ret != -1 || errno != ECHILD);

}

/* Return nonzero if the given thread is still alive.  */

static int

spu_thread_alive (unsigned long tid)

{

  return tid == current_tid;

}

/* Resume process.  */

static void

spu_resume (struct thread_resume *resume_info)

{

  while (resume_info->thread != -1

         && resume_info->thread != current_tid)

    resume_info++;

  if (resume_info->leave_stopped)

    return;

  /* We don't support hardware single-stepping right now, assume

     GDB knows to use software single-stepping.  */

  if (resume_info->step)

    fprintf (stderr, "Hardware single-step not supported.\n");

  regcache_invalidate ();

  errno = 0;

  ptrace (PTRACE_CONT, current_tid, 0, resume_info->sig);

  if (errno)

    perror_with_name ("ptrace");

}

/* Wait for process, returns status.  */

static unsigned char

spu_wait (char *status)

{

  int tid = current_tid;

  int w;

  int ret;

  while (1)

    {

      ret = waitpid (tid, &w, WNOHANG | __WALL | __WNOTHREAD);

      if (ret == -1)

        {

          if (errno != ECHILD)

            perror_with_name ("waitpid");

        }

      else if (ret > 0)

        break;

      usleep (1000);

    }

  /* On the first wait, continue running the inferior until we are

     blocked inside an spu_run system call.  */

  if (!server_waiting)

    {

      int fd;

      CORE_ADDR addr;

      while (!parse_spufs_run (&fd, &addr))

        {

          ptrace (PT_SYSCALL, tid, (PTRACE_TYPE_ARG3) 0, 0);

          waitpid (tid, NULL, __WALL | __WNOTHREAD);

        }

    }

  if (WIFEXITED (w))

    {

      fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));

      *status = 'W';

      clear_inferiors ();

      return ((unsigned char) WEXITSTATUS (w));

    }

  else if (!WIFSTOPPED (w))

    {

      fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));

      *status = 'X';

      clear_inferiors ();

      return ((unsigned char) WTERMSIG (w));

    }

  /* After attach, we may have received a SIGSTOP.  Do not return this

     as signal to GDB, or else it will try to continue with SIGSTOP ...  */

  if (!server_waiting)

    {

      *status = 'T';

      return 0;

    }

  *status = 'T';

  return ((unsigned char) WSTOPSIG (w));

}

/* Fetch inferior registers.  */

static void

spu_fetch_registers (int regno)

{

  int fd;

  CORE_ADDR addr;

  /* ??? Some callers use 0 to mean all registers.  */

  if (regno == 0)

    regno = -1;

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

  if (!parse_spufs_run (&fd, &addr))

    return;

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

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

    supply_register (SPU_ID_REGNUM, (char *)&fd);

  /* The NPC register is found at ADDR.  */

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

    {

      char buf[4];

      if (fetch_ppc_memory (addr, buf, 4) == 0)

        supply_register (SPU_PC_REGNUM, buf);

    }

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

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

    {

      unsigned char buf[16*SPU_NUM_CORE_REGS];

      char annex[32];

      int i;

      sprintf (annex, "%d/regs", fd);

      if (spu_proc_xfer_spu (annex, buf, NULL, 0, sizeof buf) == sizeof buf)

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

          supply_register (i, buf + i*16);

    }

}

/* Store inferior registers.  */

static void

spu_store_registers (int regno)

{

  int fd;

  CORE_ADDR addr;

  /* ??? Some callers use 0 to mean all registers.  */

  if (regno == 0)

    regno = -1;

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

  if (!parse_spufs_run (&fd, &addr))

    return;

  /* The NPC register is found at ADDR.  */

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

    {

      char buf[4];

      collect_register (SPU_PC_REGNUM, buf);

      store_ppc_memory (addr, buf, 4);

    }

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

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

    {

      unsigned char buf[16*SPU_NUM_CORE_REGS];

      char annex[32];

      int i;

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

        collect_register (i, buf + i*16);

      sprintf (annex, "%d/regs", fd);

      spu_proc_xfer_spu (annex, NULL, buf, 0, sizeof buf);

    }

}

/* Copy LEN bytes from inferior's memory starting at MEMADDR

   to debugger memory starting at MYADDR.  */

static int

spu_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)

{

  int fd, ret;

  CORE_ADDR addr;

  char annex[32];

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

  if (!parse_spufs_run (&fd, &addr))

    return 0;

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

  sprintf (annex, "%d/mem", fd);

  ret = spu_proc_xfer_spu (annex, myaddr, NULL, memaddr, len);

  return ret == len ? 0 : EIO;

}

/* Copy LEN bytes of data from debugger memory at MYADDR

   to inferior's memory at MEMADDR.

   On failure (cannot write the inferior)

   returns the value of errno.  */

static int

spu_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)

{

  int fd, ret;

  CORE_ADDR addr;

  char annex[32];

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

  if (!parse_spufs_run (&fd, &addr))

    return 0;

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

  sprintf (annex, "%d/mem", fd);

  ret = spu_proc_xfer_spu (annex, NULL, myaddr, memaddr, len);

  return ret == len ? 0 : EIO;

}

/* Look up special symbols -- unneded here.  */

static void

spu_look_up_symbols (void)

{

}

/* Send signal to inferior.  */

static void

spu_request_interrupt (void)

{

  syscall (SYS_tkill, current_tid, SIGINT);

}

static const char *

spu_arch_string (void)

{

  return "spu";

}

static struct target_ops spu_target_ops = {

  spu_create_inferior,

  spu_attach,

  spu_kill,

  spu_detach,

  spu_join,

  spu_thread_alive,

  spu_resume,

  spu_wait,

  spu_fetch_registers,

  spu_store_registers,

  spu_read_memory,

  spu_write_memory,

  spu_look_up_symbols,

  spu_request_interrupt,

  NULL,

  NULL,

  NULL,

  NULL,

  NULL,

  NULL,

  NULL,

  spu_arch_string,

  spu_proc_xfer_spu,

  hostio_last_error_from_errno,

};

void

initialize_low (void)

{

  static const unsigned char breakpoint[] = { 0x00, 0x00, 0x3f, 0xff };

  set_target_ops (&spu_target_ops);

  set_breakpoint_data (breakpoint, sizeof breakpoint);

  init_registers ();

}