gdb/spu-linux-nat.c

   1 /* SPU native-dependent code for GDB, the GNU debugger.
   2    Copyright (C) 2006-2012 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 "defs.h"
  22 #include "gdbcore.h"
  23 #include "gdb_string.h"
  24 #include "target.h"
  25 #include "inferior.h"
  26 #include "inf-child.h"
  27 #include "inf-ptrace.h"
  28 #include "regcache.h"
  29 #include "symfile.h"
  30 #include "gdb_wait.h"
  31 #include "gdbthread.h"
  32
  33 #include <sys/ptrace.h>
  34 #include <asm/ptrace.h>
  35 #include <sys/types.h>
  36 #include <sys/param.h>
  37
  38 #include "spu-tdep.h"
  39
  40 /* PPU side system calls.  */
  41 #define INSTR_SC        0x44000002
  42 #define NR_spu_run      0x0116
  43
  44
  45 /* Fetch PPU register REGNO.  */
  46 static ULONGEST
  47 fetch_ppc_register (int regno)
  48 {
  49   PTRACE_TYPE_RET res;
  50
  51   int tid = TIDGET (inferior_ptid);
  52   if (tid == 0)
  53     tid = PIDGET (inferior_ptid);
  54
  55 #ifndef __powerpc64__
  56   /* If running as a 32-bit process on a 64-bit system, we attempt
  57      to get the full 64-bit register content of the target process.
  58      If the PPC special ptrace call fails, we're on a 32-bit system;
  59      just fall through to the regular ptrace call in that case.  */
  60   {
  61     gdb_byte buf[8];
  62
  63     errno = 0;
  64     ptrace (PPC_PTRACE_PEEKUSR_3264, tid,
  65             (PTRACE_TYPE_ARG3) (regno * 8), buf);
  66     if (errno == 0)
  67       ptrace (PPC_PTRACE_PEEKUSR_3264, tid,
  68               (PTRACE_TYPE_ARG3) (regno * 8 + 4), buf + 4);
  69     if (errno == 0)
  70       return (ULONGEST) *(uint64_t *)buf;
  71   }
  72 #endif
  73
  74   errno = 0;
  75   res = ptrace (PT_READ_U, tid,
  76                 (PTRACE_TYPE_ARG3) (regno * sizeof (PTRACE_TYPE_RET)), 0);
  77   if (errno != 0)
  78     {
  79       char mess[128];
  80       xsnprintf (mess, sizeof mess, "reading PPC register #%d", regno);
  81       perror_with_name (_(mess));
  82     }
  83
  84   return (ULONGEST) (unsigned long) res;
  85 }
  86
  87 /* Fetch WORD from PPU memory at (aligned) MEMADDR in thread TID.  */
  88 static int
  89 fetch_ppc_memory_1 (int tid, ULONGEST memaddr, PTRACE_TYPE_RET *word)
  90 {
  91   errno = 0;
  92
  93 #ifndef __powerpc64__
  94   if (memaddr >> 32)
  95     {
  96       uint64_t addr_8 = (uint64_t) memaddr;
  97       ptrace (PPC_PTRACE_PEEKTEXT_3264, tid, (PTRACE_TYPE_ARG3) &addr_8, word);
  98     }
  99   else
 100 #endif
 101     *word = ptrace (PT_READ_I, tid, (PTRACE_TYPE_ARG3) (size_t) memaddr, 0);
 102
 103   return errno;
 104 }
 105
 106 /* Store WORD into PPU memory at (aligned) MEMADDR in thread TID.  */
 107 static int
 108 store_ppc_memory_1 (int tid, ULONGEST memaddr, PTRACE_TYPE_RET word)
 109 {
 110   errno = 0;
 111
 112 #ifndef __powerpc64__
 113   if (memaddr >> 32)
 114     {
 115       uint64_t addr_8 = (uint64_t) memaddr;
 116       ptrace (PPC_PTRACE_POKEDATA_3264, tid, (PTRACE_TYPE_ARG3) &addr_8, word);
 117     }
 118   else
 119 #endif
 120     ptrace (PT_WRITE_D, tid, (PTRACE_TYPE_ARG3) (size_t) memaddr, word);
 121
 122   return errno;
 123 }
 124
 125 /* Fetch LEN bytes of PPU memory at MEMADDR to MYADDR.  */
 126 static int
 127 fetch_ppc_memory (ULONGEST memaddr, gdb_byte *myaddr, int len)
 128 {
 129   int i, ret;
 130
 131   ULONGEST addr = memaddr & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
 132   int count = ((((memaddr + len) - addr) + sizeof (PTRACE_TYPE_RET) - 1)
 133                / sizeof (PTRACE_TYPE_RET));
 134   PTRACE_TYPE_RET *buffer;
 135
 136   int tid = TIDGET (inferior_ptid);
 137   if (tid == 0)
 138     tid = PIDGET (inferior_ptid);
 139
 140   buffer = (PTRACE_TYPE_RET *) alloca (count * sizeof (PTRACE_TYPE_RET));
 141   for (i = 0; i < count; i++, addr += sizeof (PTRACE_TYPE_RET))
 142     {
 143       ret = fetch_ppc_memory_1 (tid, addr, &buffer[i]);
 144       if (ret)
 145         return ret;
 146     }
 147
 148   memcpy (myaddr,
 149           (char *) buffer + (memaddr & (sizeof (PTRACE_TYPE_RET) - 1)),
 150           len);
 151
 152   return 0;
 153 }
 154
 155 /* Store LEN bytes from MYADDR to PPU memory at MEMADDR.  */
 156 static int
 157 store_ppc_memory (ULONGEST memaddr, const gdb_byte *myaddr, int len)
 158 {
 159   int i, ret;
 160
 161   ULONGEST addr = memaddr & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
 162   int count = ((((memaddr + len) - addr) + sizeof (PTRACE_TYPE_RET) - 1)
 163                / sizeof (PTRACE_TYPE_RET));
 164   PTRACE_TYPE_RET *buffer;
 165
 166   int tid = TIDGET (inferior_ptid);
 167   if (tid == 0)
 168     tid = PIDGET (inferior_ptid);
 169
 170   buffer = (PTRACE_TYPE_RET *) alloca (count * sizeof (PTRACE_TYPE_RET));
 171
 172   if (addr != memaddr || len < (int) sizeof (PTRACE_TYPE_RET))
 173     {
 174       ret = fetch_ppc_memory_1 (tid, addr, &buffer[0]);
 175       if (ret)
 176         return ret;
 177     }
 178
 179   if (count > 1)
 180     {
 181       ret = fetch_ppc_memory_1 (tid, addr + (count - 1)
 182                                                * sizeof (PTRACE_TYPE_RET),
 183                                 &buffer[count - 1]);
 184       if (ret)
 185         return ret;
 186     }
 187
 188   memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_TYPE_RET) - 1)),
 189           myaddr, len);
 190
 191   for (i = 0; i < count; i++, addr += sizeof (PTRACE_TYPE_RET))
 192     {
 193       ret = store_ppc_memory_1 (tid, addr, buffer[i]);
 194       if (ret)
 195         return ret;
 196     }
 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, ULONGEST *addr)
 207 {
 208   enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
 209   gdb_byte buf[4];
 210   ULONGEST pc = fetch_ppc_register (32);  /* nip */
 211
 212   /* Fetch instruction preceding current NIP.  */
 213   if (fetch_ppc_memory (pc-4, buf, 4) != 0)
 214     return 0;
 215   /* It should be a "sc" instruction.  */
 216   if (extract_unsigned_integer (buf, 4, byte_order) != INSTR_SC)
 217     return 0;
 218   /* System call number should be NR_spu_run.  */
 219   if (fetch_ppc_register (0) != NR_spu_run)
 220     return 0;
 221
 222   /* Register 3 contains fd, register 4 the NPC param pointer.  */
 223   *fd = fetch_ppc_register (34);  /* orig_gpr3 */
 224   *addr = fetch_ppc_register (4);
 225   return 1;
 226 }
 227
 228
 229 /* Copy LEN bytes at OFFSET in spufs file ANNEX into/from READBUF or WRITEBUF,
 230    using the /proc file system.  */
 231 static LONGEST
 232 spu_proc_xfer_spu (const char *annex, gdb_byte *readbuf,
 233                    const gdb_byte *writebuf,
 234                    ULONGEST offset, LONGEST len)
 235 {
 236   char buf[128];
 237   int fd = 0;
 238   int ret = -1;
 239   int pid = PIDGET (inferior_ptid);
 240
 241   if (!annex)
 242     return 0;
 243
 244   xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
 245   fd = open (buf, writebuf? O_WRONLY : O_RDONLY);
 246   if (fd <= 0)
 247     return -1;
 248
 249   if (offset != 0
 250       && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
 251     {
 252       close (fd);
 253       return 0;
 254     }
 255
 256   if (writebuf)
 257     ret = write (fd, writebuf, (size_t) len);
 258   else if (readbuf)
 259     ret = read (fd, readbuf, (size_t) len);
 260
 261   close (fd);
 262   return ret;
 263 }
 264
 265
 266 /* Inferior memory should contain an SPE executable image at location ADDR.
 267    Allocate a BFD representing that executable.  Return NULL on error.  */
 268
 269 static void *
 270 spu_bfd_iovec_open (struct bfd *nbfd, void *open_closure)
 271 {
 272   return open_closure;
 273 }
 274
 275 static int
 276 spu_bfd_iovec_close (struct bfd *nbfd, void *stream)
 277 {
 278   xfree (stream);
 279   return 1;
 280 }
 281
 282 static file_ptr
 283 spu_bfd_iovec_pread (struct bfd *abfd, void *stream, void *buf,
 284                      file_ptr nbytes, file_ptr offset)
 285 {
 286   ULONGEST addr = *(ULONGEST *)stream;
 287
 288   if (fetch_ppc_memory (addr + offset, buf, nbytes) != 0)
 289     {
 290       bfd_set_error (bfd_error_invalid_operation);
 291       return -1;
 292     }
 293
 294   return nbytes;
 295 }
 296
 297 static int
 298 spu_bfd_iovec_stat (struct bfd *abfd, void *stream, struct stat *sb)
 299 {
 300   /* We don't have an easy way of finding the size of embedded spu
 301      images.  We could parse the in-memory ELF header and section
 302      table to find the extent of the last section but that seems
 303      pointless when the size is needed only for checks of other
 304      parsed values in dbxread.c.  */
 305   sb->st_size = INT_MAX;
 306   return 0;
 307 }
 308
 309 static bfd *
 310 spu_bfd_open (ULONGEST addr)
 311 {
 312   struct bfd *nbfd;
 313   asection *spu_name;
 314
 315   ULONGEST *open_closure = xmalloc (sizeof (ULONGEST));
 316   *open_closure = addr;
 317
 318   nbfd = bfd_openr_iovec (xstrdup ("<in-memory>"), "elf32-spu",
 319                           spu_bfd_iovec_open, open_closure,
 320                           spu_bfd_iovec_pread, spu_bfd_iovec_close,
 321                           spu_bfd_iovec_stat);
 322   if (!nbfd)
 323     return NULL;
 324   nbfd = gdb_bfd_ref (nbfd);
 325
 326   if (!bfd_check_format (nbfd, bfd_object))
 327     {
 328       gdb_bfd_unref (nbfd);
 329       return NULL;
 330     }
 331
 332   /* Retrieve SPU name note and update BFD name.  */
 333   spu_name = bfd_get_section_by_name (nbfd, ".note.spu_name");
 334   if (spu_name)
 335     {
 336       int sect_size = bfd_section_size (nbfd, spu_name);
 337       if (sect_size > 20)
 338         {
 339           char *buf = alloca (sect_size - 20 + 1);
 340           bfd_get_section_contents (nbfd, spu_name, buf, 20, sect_size - 20);
 341           buf[sect_size - 20] = '\0';
 342
 343           xfree ((char *)nbfd->filename);
 344           nbfd->filename = xstrdup (buf);
 345         }
 346     }
 347
 348   return nbfd;
 349 }
 350
 351 /* INFERIOR_FD is a file handle passed by the inferior to the
 352    spu_run system call.  Assuming the SPE context was allocated
 353    by the libspe library, try to retrieve the main SPE executable
 354    file from its copy within the target process.  */
 355 static void
 356 spu_symbol_file_add_from_memory (int inferior_fd)
 357 {
 358   ULONGEST addr;
 359   struct bfd *nbfd;
 360
 361   char id[128];
 362   char annex[32];
 363   int len;
 364
 365   /* Read object ID.  */
 366   xsnprintf (annex, sizeof annex, "%d/object-id", inferior_fd);
 367   len = spu_proc_xfer_spu (annex, id, NULL, 0, sizeof id);
 368   if (len <= 0 || len >= sizeof id)
 369     return;
 370   id[len] = 0;
 371   addr = strtoulst (id, NULL, 16);
 372   if (!addr)
 373     return;
 374
 375   /* Open BFD representing SPE executable and read its symbols.  */
 376   nbfd = spu_bfd_open (addr);
 377   if (nbfd)
 378     symbol_file_add_from_bfd (nbfd, SYMFILE_VERBOSE | SYMFILE_MAINLINE,
 379                               NULL, 0, NULL);
 380 }
 381
 382
 383 /* Override the post_startup_inferior routine to continue running
 384    the inferior until the first spu_run system call.  */
 385 static void
 386 spu_child_post_startup_inferior (ptid_t ptid)
 387 {
 388   int fd;
 389   ULONGEST addr;
 390
 391   int tid = TIDGET (ptid);
 392   if (tid == 0)
 393     tid = PIDGET (ptid);
 394
 395   while (!parse_spufs_run (&fd, &addr))
 396     {
 397       ptrace (PT_SYSCALL, tid, (PTRACE_TYPE_ARG3) 0, 0);
 398       waitpid (tid, NULL, __WALL | __WNOTHREAD);
 399     }
 400 }
 401
 402 /* Override the post_attach routine to try load the SPE executable
 403    file image from its copy inside the target process.  */
 404 static void
 405 spu_child_post_attach (int pid)
 406 {
 407   int fd;
 408   ULONGEST addr;
 409
 410   /* Like child_post_startup_inferior, if we happened to attach to
 411      the inferior while it wasn't currently in spu_run, continue
 412      running it until we get back there.  */
 413   while (!parse_spufs_run (&fd, &addr))
 414     {
 415       ptrace (PT_SYSCALL, pid, (PTRACE_TYPE_ARG3) 0, 0);
 416       waitpid (pid, NULL, __WALL | __WNOTHREAD);
 417     }
 418
 419   /* If the user has not provided an executable file, try to extract
 420      the image from inside the target process.  */
 421   if (!get_exec_file (0))
 422     spu_symbol_file_add_from_memory (fd);
 423 }
 424
 425 /* Wait for child PTID to do something.  Return id of the child,
 426    minus_one_ptid in case of error; store status into *OURSTATUS.  */
 427 static ptid_t
 428 spu_child_wait (struct target_ops *ops,
 429                 ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 430 {
 431   int save_errno;
 432   int status;
 433   pid_t pid;
 434
 435   do
 436     {
 437       set_sigint_trap ();       /* Causes SIGINT to be passed on to the
 438                                    attached process.  */
 439
 440       pid = waitpid (PIDGET (ptid), &status, 0);
 441       if (pid == -1 && errno == ECHILD)
 442         /* Try again with __WCLONE to check cloned processes.  */
 443         pid = waitpid (PIDGET (ptid), &status, __WCLONE);
 444
 445       save_errno = errno;
 446
 447       /* Make sure we don't report an event for the exit of the
 448          original program, if we've detached from it.  */
 449       if (pid != -1 && !WIFSTOPPED (status) && pid != PIDGET (inferior_ptid))
 450         {
 451           pid = -1;
 452           save_errno = EINTR;
 453         }
 454
 455       clear_sigint_trap ();
 456     }
 457   while (pid == -1 && save_errno == EINTR);
 458
 459   if (pid == -1)
 460     {
 461       warning (_("Child process unexpectedly missing: %s"),
 462                safe_strerror (save_errno));
 463
 464       /* Claim it exited with unknown signal.  */
 465       ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 466       ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
 467       return inferior_ptid;
 468     }
 469
 470   store_waitstatus (ourstatus, status);
 471   return pid_to_ptid (pid);
 472 }
 473
 474 /* Override the fetch_inferior_register routine.  */
 475 static void
 476 spu_fetch_inferior_registers (struct target_ops *ops,
 477                               struct regcache *regcache, int regno)
 478 {
 479   int fd;
 480   ULONGEST addr;
 481
 482   /* We must be stopped on a spu_run system call.  */
 483   if (!parse_spufs_run (&fd, &addr))
 484     return;
 485
 486   /* The ID register holds the spufs file handle.  */
 487   if (regno == -1 || regno == SPU_ID_REGNUM)
 488     {
 489       struct gdbarch *gdbarch = get_regcache_arch (regcache);
 490       enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 491       char buf[4];
 492       store_unsigned_integer (buf, 4, byte_order, fd);
 493       regcache_raw_supply (regcache, SPU_ID_REGNUM, buf);
 494     }
 495
 496   /* The NPC register is found at ADDR.  */
 497   if (regno == -1 || regno == SPU_PC_REGNUM)
 498     {
 499       gdb_byte buf[4];
 500       if (fetch_ppc_memory (addr, buf, 4) == 0)
 501         regcache_raw_supply (regcache, SPU_PC_REGNUM, buf);
 502     }
 503
 504   /* The GPRs are found in the "regs" spufs file.  */
 505   if (regno == -1 || (regno >= 0 && regno < SPU_NUM_GPRS))
 506     {
 507       gdb_byte buf[16 * SPU_NUM_GPRS];
 508       char annex[32];
 509       int i;
 510
 511       xsnprintf (annex, sizeof annex, "%d/regs", fd);
 512       if (spu_proc_xfer_spu (annex, buf, NULL, 0, sizeof buf) == sizeof buf)
 513         for (i = 0; i < SPU_NUM_GPRS; i++)
 514           regcache_raw_supply (regcache, i, buf + i*16);
 515     }
 516 }
 517
 518 /* Override the store_inferior_register routine.  */
 519 static void
 520 spu_store_inferior_registers (struct target_ops *ops,
 521                               struct regcache *regcache, int regno)
 522 {
 523   int fd;
 524   ULONGEST addr;
 525
 526   /* We must be stopped on a spu_run system call.  */
 527   if (!parse_spufs_run (&fd, &addr))
 528     return;
 529
 530   /* The NPC register is found at ADDR.  */
 531   if (regno == -1 || regno == SPU_PC_REGNUM)
 532     {
 533       gdb_byte buf[4];
 534       regcache_raw_collect (regcache, SPU_PC_REGNUM, buf);
 535       store_ppc_memory (addr, buf, 4);
 536     }
 537
 538   /* The GPRs are found in the "regs" spufs file.  */
 539   if (regno == -1 || (regno >= 0 && regno < SPU_NUM_GPRS))
 540     {
 541       gdb_byte buf[16 * SPU_NUM_GPRS];
 542       char annex[32];
 543       int i;
 544
 545       for (i = 0; i < SPU_NUM_GPRS; i++)
 546         regcache_raw_collect (regcache, i, buf + i*16);
 547
 548       xsnprintf (annex, sizeof annex, "%d/regs", fd);
 549       spu_proc_xfer_spu (annex, NULL, buf, 0, sizeof buf);
 550     }
 551 }
 552
 553 /* Override the to_xfer_partial routine.  */
 554 static LONGEST
 555 spu_xfer_partial (struct target_ops *ops,
 556                   enum target_object object, const char *annex,
 557                   gdb_byte *readbuf, const gdb_byte *writebuf,
 558                   ULONGEST offset, LONGEST len)
 559 {
 560   if (object == TARGET_OBJECT_SPU)
 561     return spu_proc_xfer_spu (annex, readbuf, writebuf, offset, len);
 562
 563   if (object == TARGET_OBJECT_MEMORY)
 564     {
 565       int fd;
 566       ULONGEST addr;
 567       char mem_annex[32], lslr_annex[32];
 568       gdb_byte buf[32];
 569       ULONGEST lslr;
 570       LONGEST ret;
 571
 572       /* We must be stopped on a spu_run system call.  */
 573       if (!parse_spufs_run (&fd, &addr))
 574         return 0;
 575
 576       /* Use the "mem" spufs file to access SPU local store.  */
 577       xsnprintf (mem_annex, sizeof mem_annex, "%d/mem", fd);
 578       ret = spu_proc_xfer_spu (mem_annex, readbuf, writebuf, offset, len);
 579       if (ret > 0)
 580         return ret;
 581
 582       /* SPU local store access wraps the address around at the
 583          local store limit.  We emulate this here.  To avoid needing
 584          an extra access to retrieve the LSLR, we only do that after
 585          trying the original address first, and getting end-of-file.  */
 586       xsnprintf (lslr_annex, sizeof lslr_annex, "%d/lslr", fd);
 587       memset (buf, 0, sizeof buf);
 588       if (spu_proc_xfer_spu (lslr_annex, buf, NULL, 0, sizeof buf) <= 0)
 589         return ret;
 590
 591       lslr = strtoulst (buf, NULL, 16);
 592       return spu_proc_xfer_spu (mem_annex, readbuf, writebuf,
 593                                 offset & lslr, len);
 594     }
 595
 596   return -1;
 597 }
 598
 599 /* Override the to_can_use_hw_breakpoint routine.  */
 600 static int
 601 spu_can_use_hw_breakpoint (int type, int cnt, int othertype)
 602 {
 603   return 0;
 604 }
 605
 606
 607 /* Initialize SPU native target.  */
 608 void
 609 _initialize_spu_nat (void)
 610 {
 611   /* Generic ptrace methods.  */
 612   struct target_ops *t;
 613   t = inf_ptrace_target ();
 614
 615   /* Add SPU methods.  */
 616   t->to_post_attach = spu_child_post_attach;
 617   t->to_post_startup_inferior = spu_child_post_startup_inferior;
 618   t->to_wait = spu_child_wait;
 619   t->to_fetch_registers = spu_fetch_inferior_registers;
 620   t->to_store_registers = spu_store_inferior_registers;
 621   t->to_xfer_partial = spu_xfer_partial;
 622   t->to_can_use_hw_breakpoint = spu_can_use_hw_breakpoint;
 623
 624   /* Register SPU target.  */
 625   add_target (t);
 626 }