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 3 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, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "server.h"
  22
  23 #include <sys/wait.h>
  24 #include <stdio.h>
  25 #include <sys/ptrace.h>
  26 #include <fcntl.h>
  27 #include <string.h>
  28 #include <stdlib.h>
  29 #include <unistd.h>
  30 #include <errno.h>
  31 #include <sys/syscall.h>
  32
  33 /* Some older glibc versions do not define this.  */
  34 #ifndef __WNOTHREAD
  35 #define __WNOTHREAD     0x20000000      /* Don't wait on children of other
  36                                            threads in this group */
  37 #endif
  38
  39 #define PTRACE_TYPE_RET long
  40 #define PTRACE_TYPE_ARG3 long
  41
  42 /* Number of registers.  */
  43 #define SPU_NUM_REGS         130
  44 #define SPU_NUM_CORE_REGS    128
  45
  46 /* Special registers.  */
  47 #define SPU_ID_REGNUM        128
  48 #define SPU_PC_REGNUM        129
  49
  50 /* PPU side system calls.  */
  51 #define INSTR_SC        0x44000002
  52 #define NR_spu_run      0x0116
  53
  54 /* Get current thread ID (Linux task ID).  */
  55 #define current_tid ((struct inferior_list_entry *)current_inferior)->id
  56
  57 /* These are used in remote-utils.c.  */
  58 int using_threads = 0;
  59
  60
  61 /* Fetch PPU register REGNO.  */
  62 static CORE_ADDR
  63 fetch_ppc_register (int regno)
  64 {
  65   PTRACE_TYPE_RET res;
  66
  67   int tid = current_tid;
  68
  69 #ifndef __powerpc64__
  70   /* If running as a 32-bit process on a 64-bit system, we attempt
  71      to get the full 64-bit register content of the target process.
  72      If the PPC special ptrace call fails, we're on a 32-bit system;
  73      just fall through to the regular ptrace call in that case.  */
  74   {
  75     char buf[8];
  76
  77     errno = 0;
  78     ptrace (PPC_PTRACE_PEEKUSR_3264, tid,
  79             (PTRACE_TYPE_ARG3) (regno * 8), buf);
  80     if (errno == 0)
  81       ptrace (PPC_PTRACE_PEEKUSR_3264, tid,
  82               (PTRACE_TYPE_ARG3) (regno * 8 + 4), buf + 4);
  83     if (errno == 0)
  84       return (CORE_ADDR) *(unsigned long long *)buf;
  85   }
  86 #endif
  87
  88   errno = 0;
  89   res = ptrace (PT_READ_U, tid,
  90                 (PTRACE_TYPE_ARG3) (regno * sizeof (PTRACE_TYPE_RET)), 0);
  91   if (errno != 0)
  92     {
  93       char mess[128];
  94       sprintf (mess, "reading PPC register #%d", regno);
  95       perror_with_name (mess);
  96     }
  97
  98   return (CORE_ADDR) (unsigned long) res;
  99 }
 100
 101 /* Fetch WORD from PPU memory at (aligned) MEMADDR in thread TID.  */
 102 static int
 103 fetch_ppc_memory_1 (int tid, CORE_ADDR memaddr, PTRACE_TYPE_RET *word)
 104 {
 105   errno = 0;
 106
 107 #ifndef __powerpc64__
 108   if (memaddr >> 32)
 109     {
 110       unsigned long long addr_8 = (unsigned long long) memaddr;
 111       ptrace (PPC_PTRACE_PEEKTEXT_3264, tid, (PTRACE_TYPE_ARG3) &addr_8, word);
 112     }
 113   else
 114 #endif
 115     *word = ptrace (PT_READ_I, tid, (PTRACE_TYPE_ARG3) (size_t) memaddr, 0);
 116
 117   return errno;
 118 }
 119
 120 /* Store WORD into PPU memory at (aligned) MEMADDR in thread TID.  */
 121 static int
 122 store_ppc_memory_1 (int tid, CORE_ADDR memaddr, PTRACE_TYPE_RET word)
 123 {
 124   errno = 0;
 125
 126 #ifndef __powerpc64__
 127   if (memaddr >> 32)
 128     {
 129       unsigned long long addr_8 = (unsigned long long) memaddr;
 130       ptrace (PPC_PTRACE_POKEDATA_3264, tid, (PTRACE_TYPE_ARG3) &addr_8, word);
 131     }
 132   else
 133 #endif
 134     ptrace (PT_WRITE_D, tid, (PTRACE_TYPE_ARG3) (size_t) memaddr, word);
 135
 136   return errno;
 137 }
 138
 139 /* Fetch LEN bytes of PPU memory at MEMADDR to MYADDR.  */
 140 static int
 141 fetch_ppc_memory (CORE_ADDR memaddr, char *myaddr, int len)
 142 {
 143   int i, ret;
 144
 145   CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_TYPE_RET);
 146   int count = ((((memaddr + len) - addr) + sizeof (PTRACE_TYPE_RET) - 1)
 147                / sizeof (PTRACE_TYPE_RET));
 148   PTRACE_TYPE_RET *buffer;
 149
 150   int tid = current_tid;
 151
 152   buffer = (PTRACE_TYPE_RET *) alloca (count * sizeof (PTRACE_TYPE_RET));
 153   for (i = 0; i < count; i++, addr += sizeof (PTRACE_TYPE_RET))
 154     if ((ret = fetch_ppc_memory_1 (tid, addr, &buffer[i])) != 0)
 155       return ret;
 156
 157   memcpy (myaddr,
 158           (char *) buffer + (memaddr & (sizeof (PTRACE_TYPE_RET) - 1)),
 159           len);
 160
 161   return 0;
 162 }
 163
 164 /* Store LEN bytes from MYADDR to PPU memory at MEMADDR.  */
 165 static int
 166 store_ppc_memory (CORE_ADDR memaddr, char *myaddr, int len)
 167 {
 168   int i, ret;
 169
 170   CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_TYPE_RET);
 171   int count = ((((memaddr + len) - addr) + sizeof (PTRACE_TYPE_RET) - 1)
 172                / sizeof (PTRACE_TYPE_RET));
 173   PTRACE_TYPE_RET *buffer;
 174
 175   int tid = current_tid;
 176
 177   buffer = (PTRACE_TYPE_RET *) alloca (count * sizeof (PTRACE_TYPE_RET));
 178
 179   if (addr != memaddr || len < (int) sizeof (PTRACE_TYPE_RET))
 180     if ((ret = fetch_ppc_memory_1 (tid, addr, &buffer[0])) != 0)
 181       return ret;
 182
 183   if (count > 1)
 184     if ((ret = fetch_ppc_memory_1 (tid, addr + (count - 1)
 185                                                * sizeof (PTRACE_TYPE_RET),
 186                                    &buffer[count - 1])) != 0)
 187       return ret;
 188
 189   memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_TYPE_RET) - 1)),
 190           myaddr, len);
 191
 192   for (i = 0; i < count; i++, addr += sizeof (PTRACE_TYPE_RET))
 193     if ((ret = store_ppc_memory_1 (tid, addr, buffer[i])) != 0)
 194       return ret;
 195
 196   return 0;
 197 }
 198
 199
 200 /* If the PPU thread is currently stopped on a spu_run system call,
 201    return to FD and ADDR the file handle and NPC parameter address
 202    used with the system call.  Return non-zero if successful.  */
 203 static int
 204 parse_spufs_run (int *fd, CORE_ADDR *addr)
 205 {
 206   char buf[4];
 207   CORE_ADDR pc = fetch_ppc_register (32);  /* nip */
 208
 209   /* Fetch instruction preceding current NIP.  */
 210   if (fetch_ppc_memory (pc-4, buf, 4) != 0)
 211     return 0;
 212   /* It should be a "sc" instruction.  */
 213   if (*(unsigned int *)buf != INSTR_SC)
 214     return 0;
 215   /* System call number should be NR_spu_run.  */
 216   if (fetch_ppc_register (0) != NR_spu_run)
 217     return 0;
 218
 219   /* Register 3 contains fd, register 4 the NPC param pointer.  */
 220   *fd = fetch_ppc_register (34);  /* orig_gpr3 */
 221   *addr = fetch_ppc_register (4);
 222   return 1;
 223 }
 224
 225
 226 /* Copy LEN bytes at OFFSET in spufs file ANNEX into/from READBUF or WRITEBUF,
 227    using the /proc file system.  */
 228 static int
 229 spu_proc_xfer_spu (const char *annex, unsigned char *readbuf,
 230                    const unsigned char *writebuf,
 231                    CORE_ADDR offset, int len)
 232 {
 233   char buf[128];
 234   int fd = 0;
 235   int ret = -1;
 236
 237   if (!annex)
 238     return 0;
 239
 240   sprintf (buf, "/proc/%ld/fd/%s", current_tid, annex);
 241   fd = open (buf, writebuf? O_WRONLY : O_RDONLY);
 242   if (fd <= 0)
 243     return -1;
 244
 245   if (offset != 0
 246       && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
 247     {
 248       close (fd);
 249       return 0;
 250     }
 251
 252   if (writebuf)
 253     ret = write (fd, writebuf, (size_t) len);
 254   else if (readbuf)
 255     ret = read (fd, readbuf, (size_t) len);
 256
 257   close (fd);
 258   return ret;
 259 }
 260
 261
 262 /* Start an inferior process and returns its pid.
 263    ALLARGS is a vector of program-name and args. */
 264 static int
 265 spu_create_inferior (char *program, char **allargs)
 266 {
 267   int pid;
 268
 269   pid = fork ();
 270   if (pid < 0)
 271     perror_with_name ("fork");
 272
 273   if (pid == 0)
 274     {
 275       ptrace (PTRACE_TRACEME, 0, 0, 0);
 276
 277       setpgid (0, 0);
 278
 279       execv (program, allargs);
 280       if (errno == ENOENT)
 281         execvp (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 int
 318 spu_detach (void)
 319 {
 320   ptrace (PTRACE_DETACH, current_tid, 0, 0);
 321   return 0;
 322 }
 323
 324 static void
 325 spu_join (void)
 326 {
 327   int status, ret;
 328
 329   do {
 330     ret = waitpid (current_tid, &status, 0);
 331     if (WIFEXITED (status) || WIFSIGNALED (status))
 332       break;
 333   } while (ret != -1 || errno != ECHILD);
 334 }
 335
 336 /* Return nonzero if the given thread is still alive.  */
 337 static int
 338 spu_thread_alive (unsigned long tid)
 339 {
 340   return tid == current_tid;
 341 }
 342
 343 /* Resume process.  */
 344 static void
 345 spu_resume (struct thread_resume *resume_info)
 346 {
 347   while (resume_info->thread != -1
 348          && resume_info->thread != current_tid)
 349     resume_info++;
 350
 351   block_async_io ();
 352   enable_async_io ();
 353
 354   if (resume_info->leave_stopped)
 355     return;
 356
 357   /* We don't support hardware single-stepping right now, assume
 358      GDB knows to use software single-stepping.  */
 359   if (resume_info->step)
 360     fprintf (stderr, "Hardware single-step not supported.\n");
 361
 362   regcache_invalidate ();
 363
 364   errno = 0;
 365   ptrace (PTRACE_CONT, current_tid, 0, resume_info->sig);
 366   if (errno)
 367     perror_with_name ("ptrace");
 368 }
 369
 370 /* Wait for process, returns status.  */
 371 static unsigned char
 372 spu_wait (char *status)
 373 {
 374   int tid = current_tid;
 375   int w;
 376   int ret;
 377
 378   enable_async_io ();
 379   unblock_async_io ();
 380
 381   while (1)
 382     {
 383       ret = waitpid (tid, &w, WNOHANG | __WALL | __WNOTHREAD);
 384
 385       if (ret == -1)
 386         {
 387           if (errno != ECHILD)
 388             perror_with_name ("waitpid");
 389         }
 390       else if (ret > 0)
 391         break;
 392
 393       usleep (1000);
 394     }
 395
 396   /* On the first wait, continue running the inferior until we are
 397      blocked inside an spu_run system call.  */
 398   if (!server_waiting)
 399     {
 400       int fd;
 401       CORE_ADDR addr;
 402
 403       while (!parse_spufs_run (&fd, &addr))
 404         {
 405           ptrace (PT_SYSCALL, tid, (PTRACE_TYPE_ARG3) 0, 0);
 406           waitpid (tid, NULL, __WALL | __WNOTHREAD);
 407         }
 408     }
 409
 410   disable_async_io ();
 411
 412   if (WIFEXITED (w))
 413     {
 414       fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
 415       *status = 'W';
 416       clear_inferiors ();
 417       return ((unsigned char) WEXITSTATUS (w));
 418     }
 419   else if (!WIFSTOPPED (w))
 420     {
 421       fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
 422       *status = 'X';
 423       clear_inferiors ();
 424       return ((unsigned char) WTERMSIG (w));
 425     }
 426
 427   /* After attach, we may have received a SIGSTOP.  Do not return this
 428      as signal to GDB, or else it will try to continue with SIGSTOP ...  */
 429   if (!server_waiting)
 430     {
 431       *status = 'T';
 432       return 0;
 433     }
 434
 435   *status = 'T';
 436   return ((unsigned char) WSTOPSIG (w));
 437 }
 438
 439 /* Fetch inferior registers.  */
 440 static void
 441 spu_fetch_registers (int regno)
 442 {
 443   int fd;
 444   CORE_ADDR addr;
 445
 446   /* ??? Some callers use 0 to mean all registers.  */
 447   if (regno == 0)
 448     regno = -1;
 449
 450   /* We must be stopped on a spu_run system call.  */
 451   if (!parse_spufs_run (&fd, &addr))
 452     return;
 453
 454   /* The ID register holds the spufs file handle.  */
 455   if (regno == -1 || regno == SPU_ID_REGNUM)
 456     supply_register (SPU_ID_REGNUM, (char *)&fd);
 457
 458   /* The NPC register is found at ADDR.  */
 459   if (regno == -1 || regno == SPU_PC_REGNUM)
 460     {
 461       char buf[4];
 462       if (fetch_ppc_memory (addr, buf, 4) == 0)
 463         supply_register (SPU_PC_REGNUM, buf);
 464     }
 465
 466   /* The GPRs are found in the "regs" spufs file.  */
 467   if (regno == -1 || (regno >= 0 && regno < SPU_NUM_CORE_REGS))
 468     {
 469       unsigned char buf[16*SPU_NUM_CORE_REGS];
 470       char annex[32];
 471       int i;
 472
 473       sprintf (annex, "%d/regs", fd);
 474       if (spu_proc_xfer_spu (annex, buf, NULL, 0, sizeof buf) == sizeof buf)
 475         for (i = 0; i < SPU_NUM_CORE_REGS; i++)
 476           supply_register (i, buf + i*16);
 477     }
 478 }
 479
 480 /* Store inferior registers.  */
 481 static void
 482 spu_store_registers (int regno)
 483 {
 484   int fd;
 485   CORE_ADDR addr;
 486
 487   /* ??? Some callers use 0 to mean all registers.  */
 488   if (regno == 0)
 489     regno = -1;
 490
 491   /* We must be stopped on a spu_run system call.  */
 492   if (!parse_spufs_run (&fd, &addr))
 493     return;
 494
 495   /* The NPC register is found at ADDR.  */
 496   if (regno == -1 || regno == SPU_PC_REGNUM)
 497     {
 498       char buf[4];
 499       collect_register (SPU_PC_REGNUM, buf);
 500       store_ppc_memory (addr, buf, 4);
 501     }
 502
 503   /* The GPRs are found in the "regs" spufs file.  */
 504   if (regno == -1 || (regno >= 0 && regno < SPU_NUM_CORE_REGS))
 505     {
 506       unsigned char buf[16*SPU_NUM_CORE_REGS];
 507       char annex[32];
 508       int i;
 509
 510       for (i = 0; i < SPU_NUM_CORE_REGS; i++)
 511         collect_register (i, buf + i*16);
 512
 513       sprintf (annex, "%d/regs", fd);
 514       spu_proc_xfer_spu (annex, NULL, buf, 0, sizeof buf);
 515     }
 516 }
 517
 518 /* Copy LEN bytes from inferior's memory starting at MEMADDR
 519    to debugger memory starting at MYADDR.  */
 520 static int
 521 spu_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
 522 {
 523   int fd, ret;
 524   CORE_ADDR addr;
 525   char annex[32];
 526
 527   /* We must be stopped on a spu_run system call.  */
 528   if (!parse_spufs_run (&fd, &addr))
 529     return 0;
 530
 531   /* Use the "mem" spufs file to access SPU local store.  */
 532   sprintf (annex, "%d/mem", fd);
 533   ret = spu_proc_xfer_spu (annex, myaddr, NULL, memaddr, len);
 534   return ret == len ? 0 : EIO;
 535 }
 536
 537 /* Copy LEN bytes of data from debugger memory at MYADDR
 538    to inferior's memory at MEMADDR.
 539    On failure (cannot write the inferior)
 540    returns the value of errno.  */
 541 static int
 542 spu_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
 543 {
 544   int fd, ret;
 545   CORE_ADDR addr;
 546   char annex[32];
 547
 548   /* We must be stopped on a spu_run system call.  */
 549   if (!parse_spufs_run (&fd, &addr))
 550     return 0;
 551
 552   /* Use the "mem" spufs file to access SPU local store.  */
 553   sprintf (annex, "%d/mem", fd);
 554   ret = spu_proc_xfer_spu (annex, NULL, myaddr, memaddr, len);
 555   return ret == len ? 0 : EIO;
 556 }
 557
 558 /* Look up special symbols -- unneded here.  */
 559 static void
 560 spu_look_up_symbols (void)
 561 {
 562 }
 563
 564 /* Send signal to inferior.  */
 565 static void
 566 spu_request_interrupt (void)
 567 {
 568   syscall (SYS_tkill, current_tid, SIGINT);
 569 }
 570
 571 static const char *
 572 spu_arch_string (void)
 573 {
 574   return "spu";
 575 }
 576
 577 static struct target_ops spu_target_ops = {
 578   spu_create_inferior,
 579   spu_attach,
 580   spu_kill,
 581   spu_detach,
 582   spu_join,
 583   spu_thread_alive,
 584   spu_resume,
 585   spu_wait,
 586   spu_fetch_registers,
 587   spu_store_registers,
 588   spu_read_memory,
 589   spu_write_memory,
 590   spu_look_up_symbols,
 591   spu_request_interrupt,
 592   NULL,
 593   NULL,
 594   NULL,
 595   NULL,
 596   NULL,
 597   NULL,
 598   NULL,
 599   spu_arch_string,
 600   spu_proc_xfer_spu,
 601 };
 602
 603 void
 604 initialize_low (void)
 605 {
 606   static const unsigned char breakpoint[] = { 0x00, 0x00, 0x3f, 0xff };
 607
 608   set_target_ops (&spu_target_ops);
 609   set_breakpoint_data (breakpoint, sizeof breakpoint);
 610   init_registers ();
 611 }