gdb/gdbserver/spu-low.c

   1 /* Low level interface to SPUs, for the remote server for GDB.
   2    Copyright (C) 2006, 2007 Free Software Foundation, Inc.
   3
   4    Contributed by Ulrich Weigand <uweigand@de.ibm.com>.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  21    Boston, MA 02110-1301, USA.  */
  22
  23 #include "server.h"
  24
  25 #include <sys/wait.h>
  26 #include <stdio.h>
  27 #include <sys/ptrace.h>
  28 #include <fcntl.h>
  29 #include <string.h>
  30 #include <stdlib.h>
  31 #include <unistd.h>
  32 #include <errno.h>
  33 #include <sys/syscall.h>
  34
  35 /* Some older glibc versions do not define this.  */
  36 #ifndef __WNOTHREAD
  37 #define __WNOTHREAD     0x20000000      /* Don't wait on children of other
  38                                            threads in this group */
  39 #endif
  40
  41 #define PTRACE_TYPE_RET long
  42 #define PTRACE_TYPE_ARG3 long
  43
  44 /* Number of registers.  */
  45 #define SPU_NUM_REGS         130
  46 #define SPU_NUM_CORE_REGS    128
  47
  48 /* Special registers.  */
  49 #define SPU_ID_REGNUM        128
  50 #define SPU_PC_REGNUM        129
  51
  52 /* PPU side system calls.  */
  53 #define INSTR_SC        0x44000002
  54 #define NR_spu_run      0x0116
  55
  56 /* Get current thread ID (Linux task ID).  */
  57 #define current_tid ((struct inferior_list_entry *)current_inferior)->id
  58
  59 /* These are used in remote-utils.c.  */
  60 int using_threads = 0;
  61
  62
  63 /* Fetch PPU register REGNO.  */
  64 static CORE_ADDR
  65 fetch_ppc_register (int regno)
  66 {
  67   PTRACE_TYPE_RET res;
  68
  69   int tid = current_tid;
  70
  71 #ifndef __powerpc64__
  72   /* If running as a 32-bit process on a 64-bit system, we attempt
  73      to get the full 64-bit register content of the target process.
  74      If the PPC special ptrace call fails, we're on a 32-bit system;
  75      just fall through to the regular ptrace call in that case.  */
  76   {
  77     char buf[8];
  78
  79     errno = 0;
  80     ptrace (PPC_PTRACE_PEEKUSR_3264, tid,
  81             (PTRACE_TYPE_ARG3) (regno * 8), buf);
  82     if (errno == 0)
  83       ptrace (PPC_PTRACE_PEEKUSR_3264, tid,
  84               (PTRACE_TYPE_ARG3) (regno * 8 + 4), buf + 4);
  85     if (errno == 0)
  86       return (CORE_ADDR) *(unsigned long long *)buf;
  87   }
  88 #endif
  89
  90   errno = 0;
  91   res = ptrace (PT_READ_U, tid,
  92                 (PTRACE_TYPE_ARG3) (regno * sizeof (PTRACE_TYPE_RET)), 0);
  93   if (errno != 0)
  94     {
  95       char mess[128];
  96       sprintf (mess, "reading PPC register #%d", regno);
  97       perror_with_name (mess);
  98     }
  99
 100   return (CORE_ADDR) (unsigned long) res;
 101 }
 102
 103 /* Fetch WORD from PPU memory at (aligned) MEMADDR in thread TID.  */
 104 static int
 105 fetch_ppc_memory_1 (int tid, CORE_ADDR memaddr, PTRACE_TYPE_RET *word)
 106 {
 107   errno = 0;
 108
 109 #ifndef __powerpc64__
 110   if (memaddr >> 32)
 111     {
 112       unsigned long long addr_8 = (unsigned long long) memaddr;
 113       ptrace (PPC_PTRACE_PEEKTEXT_3264, tid, (PTRACE_TYPE_ARG3) &addr_8, word);
 114     }
 115   else
 116 #endif
 117     *word = ptrace (PT_READ_I, tid, (PTRACE_TYPE_ARG3) (size_t) memaddr, 0);
 118
 119   return errno;
 120 }
 121
 122 /* Store WORD into PPU memory at (aligned) MEMADDR in thread TID.  */
 123 static int
 124 store_ppc_memory_1 (int tid, CORE_ADDR memaddr, PTRACE_TYPE_RET word)
 125 {
 126   errno = 0;
 127
 128 #ifndef __powerpc64__
 129   if (memaddr >> 32)
 130     {
 131       unsigned long long addr_8 = (unsigned long long) memaddr;
 132       ptrace (PPC_PTRACE_POKEDATA_3264, tid, (PTRACE_TYPE_ARG3) &addr_8, word);
 133     }
 134   else
 135 #endif
 136     ptrace (PT_WRITE_D, tid, (PTRACE_TYPE_ARG3) (size_t) memaddr, word);
 137
 138   return errno;
 139 }
 140
 141 /* Fetch LEN bytes of PPU memory at MEMADDR to MYADDR.  */
 142 static int
 143 fetch_ppc_memory (CORE_ADDR memaddr, char *myaddr, int len)
 144 {
 145   int i, ret;
 146
 147   CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_TYPE_RET);
 148   int count = ((((memaddr + len) - addr) + sizeof (PTRACE_TYPE_RET) - 1)
 149                / sizeof (PTRACE_TYPE_RET));
 150   PTRACE_TYPE_RET *buffer;
 151
 152   int tid = current_tid;
 153
 154   buffer = (PTRACE_TYPE_RET *) alloca (count * sizeof (PTRACE_TYPE_RET));
 155   for (i = 0; i < count; i++, addr += sizeof (PTRACE_TYPE_RET))
 156     if ((ret = fetch_ppc_memory_1 (tid, addr, &buffer[i])) != 0)
 157       return ret;
 158
 159   memcpy (myaddr,
 160           (char *) buffer + (memaddr & (sizeof (PTRACE_TYPE_RET) - 1)),
 161           len);
 162
 163   return 0;
 164 }
 165
 166 /* Store LEN bytes from MYADDR to PPU memory at MEMADDR.  */
 167 static int
 168 store_ppc_memory (CORE_ADDR memaddr, char *myaddr, int len)
 169 {
 170   int i, ret;
 171
 172   CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_TYPE_RET);
 173   int count = ((((memaddr + len) - addr) + sizeof (PTRACE_TYPE_RET) - 1)
 174                / sizeof (PTRACE_TYPE_RET));
 175   PTRACE_TYPE_RET *buffer;
 176
 177   int tid = current_tid;
 178
 179   buffer = (PTRACE_TYPE_RET *) alloca (count * sizeof (PTRACE_TYPE_RET));
 180
 181   if (addr != memaddr || len < (int) sizeof (PTRACE_TYPE_RET))
 182     if ((ret = fetch_ppc_memory_1 (tid, addr, &buffer[0])) != 0)
 183       return ret;
 184
 185   if (count > 1)
 186     if ((ret = fetch_ppc_memory_1 (tid, addr + (count - 1)
 187                                                * sizeof (PTRACE_TYPE_RET),
 188                                    &buffer[count - 1])) != 0)
 189       return ret;
 190
 191   memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_TYPE_RET) - 1)),
 192           myaddr, len);
 193
 194   for (i = 0; i < count; i++, addr += sizeof (PTRACE_TYPE_RET))
 195     if ((ret = store_ppc_memory_1 (tid, addr, buffer[i])) != 0)
 196       return ret;
 197
 198   return 0;
 199 }
 200
 201
 202 /* If the PPU thread is currently stopped on a spu_run system call,
 203    return to FD and ADDR the file handle and NPC parameter address
 204    used with the system call.  Return non-zero if successful.  */
 205 static int
 206 parse_spufs_run (int *fd, CORE_ADDR *addr)
 207 {
 208   char buf[4];
 209   CORE_ADDR pc = fetch_ppc_register (32);  /* nip */
 210
 211   /* Fetch instruction preceding current NIP.  */
 212   if (fetch_ppc_memory (pc-4, buf, 4) != 0)
 213     return 0;
 214   /* It should be a "sc" instruction.  */
 215   if (*(unsigned int *)buf != INSTR_SC)
 216     return 0;
 217   /* System call number should be NR_spu_run.  */
 218   if (fetch_ppc_register (0) != NR_spu_run)
 219     return 0;
 220
 221   /* Register 3 contains fd, register 4 the NPC param pointer.  */
 222   *fd = fetch_ppc_register (34);  /* orig_gpr3 */
 223   *addr = fetch_ppc_register (4);
 224   return 1;
 225 }
 226
 227
 228 /* Copy LEN bytes at OFFSET in spufs file ANNEX into/from READBUF or WRITEBUF,
 229    using the /proc file system.  */
 230 static int
 231 spu_proc_xfer_spu (const char *annex, unsigned char *readbuf,
 232                    const unsigned char *writebuf,
 233                    CORE_ADDR offset, int len)
 234 {
 235   char buf[128];
 236   int fd = 0;
 237   int ret = -1;
 238
 239   if (!annex)
 240     return 0;
 241
 242   sprintf (buf, "/proc/%ld/fd/%s", current_tid, annex);
 243   fd = open (buf, writebuf? O_WRONLY : O_RDONLY);
 244   if (fd <= 0)
 245     return -1;
 246
 247   if (offset != 0
 248       && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
 249     {
 250       close (fd);
 251       return -1;
 252     }
 253
 254   if (writebuf)
 255     ret = write (fd, writebuf, (size_t) len);
 256   else if (readbuf)
 257     ret = read (fd, readbuf, (size_t) len);
 258
 259   close (fd);
 260   return ret;
 261 }
 262
 263
 264 /* Start an inferior process and returns its pid.
 265    ALLARGS is a vector of program-name and args. */
 266 static int
 267 spu_create_inferior (char *program, char **allargs)
 268 {
 269   int pid;
 270
 271   pid = fork ();
 272   if (pid < 0)
 273     perror_with_name ("fork");
 274
 275   if (pid == 0)
 276     {
 277       ptrace (PTRACE_TRACEME, 0, 0, 0);
 278
 279       setpgid (0, 0);
 280
 281       execv (program, allargs);
 282
 283       fprintf (stderr, "Cannot exec %s: %s.\n", program,
 284                strerror (errno));
 285       fflush (stderr);
 286       _exit (0177);
 287     }
 288
 289   add_thread (pid, NULL, pid);
 290   return pid;
 291 }
 292
 293 /* Attach to an inferior process.  */
 294 int
 295 spu_attach (unsigned long  pid)
 296 {
 297   if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0)
 298     {
 299       fprintf (stderr, "Cannot attach to process %ld: %s (%d)\n", pid,
 300                strerror (errno), errno);
 301       fflush (stderr);
 302       _exit (0177);
 303     }
 304
 305   add_thread (pid, NULL, pid);
 306   return 0;
 307 }
 308
 309 /* Kill the inferior process.  */
 310 static void
 311 spu_kill (void)
 312 {
 313   ptrace (PTRACE_KILL, current_tid, 0, 0);
 314 }
 315
 316 /* Detach from inferior process.  */
 317 static void
 318 spu_detach (void)
 319 {
 320   ptrace (PTRACE_DETACH, current_tid, 0, 0);
 321 }
 322
 323 /* Return nonzero if the given thread is still alive.  */
 324 static int
 325 spu_thread_alive (unsigned long tid)
 326 {
 327   return tid == current_tid;
 328 }
 329
 330 /* Resume process.  */
 331 static void
 332 spu_resume (struct thread_resume *resume_info)
 333 {
 334   while (resume_info->thread != -1
 335          && resume_info->thread != current_tid)
 336     resume_info++;
 337
 338   block_async_io ();
 339   enable_async_io ();
 340
 341   if (resume_info->leave_stopped)
 342     return;
 343
 344   /* We don't support hardware single-stepping right now, assume
 345      GDB knows to use software single-stepping.  */
 346   if (resume_info->step)
 347     fprintf (stderr, "Hardware single-step not supported.\n");
 348
 349   regcache_invalidate ();
 350
 351   errno = 0;
 352   ptrace (PTRACE_CONT, current_tid, 0, resume_info->sig);
 353   if (errno)
 354     perror_with_name ("ptrace");
 355 }
 356
 357 /* Wait for process, returns status.  */
 358 static unsigned char
 359 spu_wait (char *status)
 360 {
 361   int tid = current_tid;
 362   int w;
 363   int ret;
 364
 365   enable_async_io ();
 366   unblock_async_io ();
 367
 368   while (1)
 369     {
 370       ret = waitpid (tid, &w, WNOHANG | __WALL | __WNOTHREAD);
 371
 372       if (ret == -1)
 373         {
 374           if (errno != ECHILD)
 375             perror_with_name ("waitpid");
 376         }
 377       else if (ret > 0)
 378         break;
 379
 380       usleep (1000);
 381     }
 382
 383   /* On the first wait, continue running the inferior until we are
 384      blocked inside an spu_run system call.  */
 385   if (!server_waiting)
 386     {
 387       int fd;
 388       CORE_ADDR addr;
 389
 390       while (!parse_spufs_run (&fd, &addr))
 391         {
 392           ptrace (PT_SYSCALL, tid, (PTRACE_TYPE_ARG3) 0, 0);
 393           waitpid (tid, NULL, __WALL | __WNOTHREAD);
 394         }
 395     }
 396
 397   disable_async_io ();
 398
 399   if (WIFEXITED (w))
 400     {
 401       fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
 402       *status = 'W';
 403       clear_inferiors ();
 404       return ((unsigned char) WEXITSTATUS (w));
 405     }
 406   else if (!WIFSTOPPED (w))
 407     {
 408       fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
 409       *status = 'X';
 410       clear_inferiors ();
 411       return ((unsigned char) WTERMSIG (w));
 412     }
 413
 414   /* After attach, we may have received a SIGSTOP.  Do not return this
 415      as signal to GDB, or else it will try to continue with SIGSTOP ...  */
 416   if (!server_waiting)
 417     {
 418       *status = 'T';
 419       return 0;
 420     }
 421
 422   *status = 'T';
 423   return ((unsigned char) WSTOPSIG (w));
 424 }
 425
 426 /* Fetch inferior registers.  */
 427 static void
 428 spu_fetch_registers (int regno)
 429 {
 430   int fd;
 431   CORE_ADDR addr;
 432
 433   /* ??? Some callers use 0 to mean all registers.  */
 434   if (regno == 0)
 435     regno = -1;
 436
 437   /* We must be stopped on a spu_run system call.  */
 438   if (!parse_spufs_run (&fd, &addr))
 439     return;
 440
 441   /* The ID register holds the spufs file handle.  */
 442   if (regno == -1 || regno == SPU_ID_REGNUM)
 443     supply_register (SPU_ID_REGNUM, (char *)&fd);
 444
 445   /* The NPC register is found at ADDR.  */
 446   if (regno == -1 || regno == SPU_PC_REGNUM)
 447     {
 448       char buf[4];
 449       if (fetch_ppc_memory (addr, buf, 4) == 0)
 450         supply_register (SPU_PC_REGNUM, buf);
 451     }
 452
 453   /* The GPRs are found in the "regs" spufs file.  */
 454   if (regno == -1 || (regno >= 0 && regno < SPU_NUM_CORE_REGS))
 455     {
 456       unsigned char buf[16*SPU_NUM_CORE_REGS];
 457       char annex[32];
 458       int i;
 459
 460       sprintf (annex, "%d/regs", fd);
 461       if (spu_proc_xfer_spu (annex, buf, NULL, 0, sizeof buf) == sizeof buf)
 462         for (i = 0; i < SPU_NUM_CORE_REGS; i++)
 463           supply_register (i, buf + i*16);
 464     }
 465 }
 466
 467 /* Store inferior registers.  */
 468 static void
 469 spu_store_registers (int regno)
 470 {
 471   int fd;
 472   CORE_ADDR addr;
 473
 474   /* ??? Some callers use 0 to mean all registers.  */
 475   if (regno == 0)
 476     regno = -1;
 477
 478   /* We must be stopped on a spu_run system call.  */
 479   if (!parse_spufs_run (&fd, &addr))
 480     return;
 481
 482   /* The NPC register is found at ADDR.  */
 483   if (regno == -1 || regno == SPU_PC_REGNUM)
 484     {
 485       char buf[4];
 486       collect_register (SPU_PC_REGNUM, buf);
 487       store_ppc_memory (addr, buf, 4);
 488     }
 489
 490   /* The GPRs are found in the "regs" spufs file.  */
 491   if (regno == -1 || (regno >= 0 && regno < SPU_NUM_CORE_REGS))
 492     {
 493       unsigned char buf[16*SPU_NUM_CORE_REGS];
 494       char annex[32];
 495       int i;
 496
 497       for (i = 0; i < SPU_NUM_CORE_REGS; i++)
 498         collect_register (i, buf + i*16);
 499
 500       sprintf (annex, "%d/regs", fd);
 501       spu_proc_xfer_spu (annex, NULL, buf, 0, sizeof buf);
 502     }
 503 }
 504
 505 /* Copy LEN bytes from inferior's memory starting at MEMADDR
 506    to debugger memory starting at MYADDR.  */
 507 static int
 508 spu_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
 509 {
 510   int fd, ret;
 511   CORE_ADDR addr;
 512   char annex[32];
 513
 514   /* We must be stopped on a spu_run system call.  */
 515   if (!parse_spufs_run (&fd, &addr))
 516     return 0;
 517
 518   /* Use the "mem" spufs file to access SPU local store.  */
 519   sprintf (annex, "%d/mem", fd);
 520   ret = spu_proc_xfer_spu (annex, myaddr, NULL, memaddr, len);
 521   return ret == len ? 0 : EIO;
 522 }
 523
 524 /* Copy LEN bytes of data from debugger memory at MYADDR
 525    to inferior's memory at MEMADDR.
 526    On failure (cannot write the inferior)
 527    returns the value of errno.  */
 528 static int
 529 spu_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
 530 {
 531   int fd, ret;
 532   CORE_ADDR addr;
 533   char annex[32];
 534
 535   /* We must be stopped on a spu_run system call.  */
 536   if (!parse_spufs_run (&fd, &addr))
 537     return 0;
 538
 539   /* Use the "mem" spufs file to access SPU local store.  */
 540   sprintf (annex, "%d/mem", fd);
 541   ret = spu_proc_xfer_spu (annex, NULL, myaddr, memaddr, len);
 542   return ret == len ? 0 : EIO;
 543 }
 544
 545 /* Look up special symbols -- unneded here.  */
 546 static void
 547 spu_look_up_symbols (void)
 548 {
 549 }
 550
 551 /* Send signal to inferior.  */
 552 static void
 553 spu_request_interrupt (void)
 554 {
 555   syscall (SYS_tkill, current_tid, SIGINT);
 556 }
 557
 558 static const char *
 559 spu_arch_string (void)
 560 {
 561   return "spu";
 562 }
 563
 564 \f
 565 static struct target_ops spu_target_ops = {
 566   spu_create_inferior,
 567   spu_attach,
 568   spu_kill,
 569   spu_detach,
 570   spu_thread_alive,
 571   spu_resume,
 572   spu_wait,
 573   spu_fetch_registers,
 574   spu_store_registers,
 575   spu_read_memory,
 576   spu_write_memory,
 577   spu_look_up_symbols,
 578   spu_request_interrupt,
 579   NULL,
 580   NULL,
 581   NULL,
 582   NULL,
 583   NULL,
 584   NULL,
 585   NULL,
 586   spu_arch_string,
 587 };
 588
 589 void
 590 initialize_low (void)
 591 {
 592   static const unsigned char breakpoint[] = { 0x00, 0x00, 0x3f, 0xff };
 593
 594   set_target_ops (&spu_target_ops);
 595   set_breakpoint_data (breakpoint, sizeof breakpoint);
 596   init_registers ();
 597 }