gdb/gdbserver/spu-low.c

   1 /* Low level interface to SPUs, for the remote server for GDB.
   2    Copyright (C) 2006, 2007, 2008, 2009 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 /* Defined in auto-generated file reg-spu.c.  */
  61 void init_registers_spu (void);
  62
  63
  64 /* Fetch PPU register REGNO.  */
  65 static CORE_ADDR
  66 fetch_ppc_register (int regno)
  67 {
  68   PTRACE_TYPE_RET res;
  69
  70   int tid = current_tid;
  71
  72 #ifndef __powerpc64__
  73   /* If running as a 32-bit process on a 64-bit system, we attempt
  74      to get the full 64-bit register content of the target process.
  75      If the PPC special ptrace call fails, we're on a 32-bit system;
  76      just fall through to the regular ptrace call in that case.  */
  77   {
  78     char buf[8];
  79
  80     errno = 0;
  81     ptrace (PPC_PTRACE_PEEKUSR_3264, tid,
  82             (PTRACE_TYPE_ARG3) (regno * 8), buf);
  83     if (errno == 0)
  84       ptrace (PPC_PTRACE_PEEKUSR_3264, tid,
  85               (PTRACE_TYPE_ARG3) (regno * 8 + 4), buf + 4);
  86     if (errno == 0)
  87       return (CORE_ADDR) *(unsigned long long *)buf;
  88   }
  89 #endif
  90
  91   errno = 0;
  92   res = ptrace (PT_READ_U, tid,
  93                 (PTRACE_TYPE_ARG3) (regno * sizeof (PTRACE_TYPE_RET)), 0);
  94   if (errno != 0)
  95     {
  96       char mess[128];
  97       sprintf (mess, "reading PPC register #%d", regno);
  98       perror_with_name (mess);
  99     }
 100
 101   return (CORE_ADDR) (unsigned long) res;
 102 }
 103
 104 /* Fetch WORD from PPU memory at (aligned) MEMADDR in thread TID.  */
 105 static int
 106 fetch_ppc_memory_1 (int tid, CORE_ADDR memaddr, PTRACE_TYPE_RET *word)
 107 {
 108   errno = 0;
 109
 110 #ifndef __powerpc64__
 111   if (memaddr >> 32)
 112     {
 113       unsigned long long addr_8 = (unsigned long long) memaddr;
 114       ptrace (PPC_PTRACE_PEEKTEXT_3264, tid, (PTRACE_TYPE_ARG3) &addr_8, word);
 115     }
 116   else
 117 #endif
 118     *word = ptrace (PT_READ_I, tid, (PTRACE_TYPE_ARG3) (size_t) memaddr, 0);
 119
 120   return errno;
 121 }
 122
 123 /* Store WORD into PPU memory at (aligned) MEMADDR in thread TID.  */
 124 static int
 125 store_ppc_memory_1 (int tid, CORE_ADDR memaddr, PTRACE_TYPE_RET word)
 126 {
 127   errno = 0;
 128
 129 #ifndef __powerpc64__
 130   if (memaddr >> 32)
 131     {
 132       unsigned long long addr_8 = (unsigned long long) memaddr;
 133       ptrace (PPC_PTRACE_POKEDATA_3264, tid, (PTRACE_TYPE_ARG3) &addr_8, word);
 134     }
 135   else
 136 #endif
 137     ptrace (PT_WRITE_D, tid, (PTRACE_TYPE_ARG3) (size_t) memaddr, word);
 138
 139   return errno;
 140 }
 141
 142 /* Fetch LEN bytes of PPU memory at MEMADDR to MYADDR.  */
 143 static int
 144 fetch_ppc_memory (CORE_ADDR memaddr, char *myaddr, int len)
 145 {
 146   int i, ret;
 147
 148   CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_TYPE_RET);
 149   int count = ((((memaddr + len) - addr) + sizeof (PTRACE_TYPE_RET) - 1)
 150                / sizeof (PTRACE_TYPE_RET));
 151   PTRACE_TYPE_RET *buffer;
 152
 153   int tid = current_tid;
 154
 155   buffer = (PTRACE_TYPE_RET *) alloca (count * sizeof (PTRACE_TYPE_RET));
 156   for (i = 0; i < count; i++, addr += sizeof (PTRACE_TYPE_RET))
 157     if ((ret = fetch_ppc_memory_1 (tid, addr, &buffer[i])) != 0)
 158       return ret;
 159
 160   memcpy (myaddr,
 161           (char *) buffer + (memaddr & (sizeof (PTRACE_TYPE_RET) - 1)),
 162           len);
 163
 164   return 0;
 165 }
 166
 167 /* Store LEN bytes from MYADDR to PPU memory at MEMADDR.  */
 168 static int
 169 store_ppc_memory (CORE_ADDR memaddr, char *myaddr, int len)
 170 {
 171   int i, ret;
 172
 173   CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_TYPE_RET);
 174   int count = ((((memaddr + len) - addr) + sizeof (PTRACE_TYPE_RET) - 1)
 175                / sizeof (PTRACE_TYPE_RET));
 176   PTRACE_TYPE_RET *buffer;
 177
 178   int tid = current_tid;
 179
 180   buffer = (PTRACE_TYPE_RET *) alloca (count * sizeof (PTRACE_TYPE_RET));
 181
 182   if (addr != memaddr || len < (int) sizeof (PTRACE_TYPE_RET))
 183     if ((ret = fetch_ppc_memory_1 (tid, addr, &buffer[0])) != 0)
 184       return ret;
 185
 186   if (count > 1)
 187     if ((ret = fetch_ppc_memory_1 (tid, addr + (count - 1)
 188                                                * sizeof (PTRACE_TYPE_RET),
 189                                    &buffer[count - 1])) != 0)
 190       return ret;
 191
 192   memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_TYPE_RET) - 1)),
 193           myaddr, len);
 194
 195   for (i = 0; i < count; i++, addr += sizeof (PTRACE_TYPE_RET))
 196     if ((ret = store_ppc_memory_1 (tid, addr, buffer[i])) != 0)
 197       return ret;
 198
 199   return 0;
 200 }
 201
 202
 203 /* If the PPU thread is currently stopped on a spu_run system call,
 204    return to FD and ADDR the file handle and NPC parameter address
 205    used with the system call.  Return non-zero if successful.  */
 206 static int
 207 parse_spufs_run (int *fd, CORE_ADDR *addr)
 208 {
 209   char buf[4];
 210   CORE_ADDR 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 (*(unsigned int *)buf != 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 int
 232 spu_proc_xfer_spu (const char *annex, unsigned char *readbuf,
 233                    const unsigned char *writebuf,
 234                    CORE_ADDR offset, int len)
 235 {
 236   char buf[128];
 237   int fd = 0;
 238   int ret = -1;
 239
 240   if (!annex)
 241     return 0;
 242
 243   sprintf (buf, "/proc/%ld/fd/%s", current_tid, annex);
 244   fd = open (buf, writebuf? O_WRONLY : O_RDONLY);
 245   if (fd <= 0)
 246     return -1;
 247
 248   if (offset != 0
 249       && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
 250     {
 251       close (fd);
 252       return 0;
 253     }
 254
 255   if (writebuf)
 256     ret = write (fd, writebuf, (size_t) len);
 257   else if (readbuf)
 258     ret = read (fd, readbuf, (size_t) len);
 259
 260   close (fd);
 261   return ret;
 262 }
 263
 264
 265 /* Start an inferior process and returns its pid.
 266    ALLARGS is a vector of program-name and args. */
 267 static int
 268 spu_create_inferior (char *program, char **allargs)
 269 {
 270   int pid;
 271
 272   pid = fork ();
 273   if (pid < 0)
 274     perror_with_name ("fork");
 275
 276   if (pid == 0)
 277     {
 278       ptrace (PTRACE_TRACEME, 0, 0, 0);
 279
 280       setpgid (0, 0);
 281
 282       execv (program, allargs);
 283       if (errno == ENOENT)
 284         execvp (program, allargs);
 285
 286       fprintf (stderr, "Cannot exec %s: %s.\n", program,
 287                strerror (errno));
 288       fflush (stderr);
 289       _exit (0177);
 290     }
 291
 292   add_thread (pid, NULL, pid);
 293   return pid;
 294 }
 295
 296 /* Attach to an inferior process.  */
 297 int
 298 spu_attach (unsigned long  pid)
 299 {
 300   if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0)
 301     {
 302       fprintf (stderr, "Cannot attach to process %ld: %s (%d)\n", pid,
 303                strerror (errno), errno);
 304       fflush (stderr);
 305       _exit (0177);
 306     }
 307
 308   add_thread (pid, NULL, pid);
 309   return 0;
 310 }
 311
 312 /* Kill the inferior process.  */
 313 static void
 314 spu_kill (void)
 315 {
 316   ptrace (PTRACE_KILL, current_tid, 0, 0);
 317 }
 318
 319 /* Detach from inferior process.  */
 320 static int
 321 spu_detach (void)
 322 {
 323   ptrace (PTRACE_DETACH, current_tid, 0, 0);
 324   return 0;
 325 }
 326
 327 static void
 328 spu_join (void)
 329 {
 330   int status, ret;
 331
 332   do {
 333     ret = waitpid (current_tid, &status, 0);
 334     if (WIFEXITED (status) || WIFSIGNALED (status))
 335       break;
 336   } while (ret != -1 || errno != ECHILD);
 337 }
 338
 339 /* Return nonzero if the given thread is still alive.  */
 340 static int
 341 spu_thread_alive (unsigned long tid)
 342 {
 343   return tid == current_tid;
 344 }
 345
 346 /* Resume process.  */
 347 static void
 348 spu_resume (struct thread_resume *resume_info, size_t n)
 349 {
 350   size_t i;
 351
 352   for (i = 0; i < n; i++)
 353     if (resume_info[i].thread == -1
 354         || resume_info[i].thread == current_tid)
 355       break;
 356
 357   if (i == n)
 358     return;
 359
 360   /* We don't support hardware single-stepping right now, assume
 361      GDB knows to use software single-stepping.  */
 362   if (resume_info[i].step)
 363     fprintf (stderr, "Hardware single-step not supported.\n");
 364
 365   regcache_invalidate ();
 366
 367   errno = 0;
 368   ptrace (PTRACE_CONT, current_tid, 0, resume_info[i].sig);
 369   if (errno)
 370     perror_with_name ("ptrace");
 371 }
 372
 373 /* Wait for process, returns status.  */
 374 static unsigned char
 375 spu_wait (char *status)
 376 {
 377   int tid = current_tid;
 378   int w;
 379   int ret;
 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   if (WIFEXITED (w))
 411     {
 412       fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
 413       *status = 'W';
 414       clear_inferiors ();
 415       return ((unsigned char) WEXITSTATUS (w));
 416     }
 417   else if (!WIFSTOPPED (w))
 418     {
 419       fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
 420       *status = 'X';
 421       clear_inferiors ();
 422       return ((unsigned char) WTERMSIG (w));
 423     }
 424
 425   /* After attach, we may have received a SIGSTOP.  Do not return this
 426      as signal to GDB, or else it will try to continue with SIGSTOP ...  */
 427   if (!server_waiting)
 428     {
 429       *status = 'T';
 430       return 0;
 431     }
 432
 433   *status = 'T';
 434   return ((unsigned char) WSTOPSIG (w));
 435 }
 436
 437 /* Fetch inferior registers.  */
 438 static void
 439 spu_fetch_registers (int regno)
 440 {
 441   int fd;
 442   CORE_ADDR addr;
 443
 444   /* ??? Some callers use 0 to mean all registers.  */
 445   if (regno == 0)
 446     regno = -1;
 447
 448   /* We must be stopped on a spu_run system call.  */
 449   if (!parse_spufs_run (&fd, &addr))
 450     return;
 451
 452   /* The ID register holds the spufs file handle.  */
 453   if (regno == -1 || regno == SPU_ID_REGNUM)
 454     supply_register (SPU_ID_REGNUM, (char *)&fd);
 455
 456   /* The NPC register is found at ADDR.  */
 457   if (regno == -1 || regno == SPU_PC_REGNUM)
 458     {
 459       char buf[4];
 460       if (fetch_ppc_memory (addr, buf, 4) == 0)
 461         supply_register (SPU_PC_REGNUM, buf);
 462     }
 463
 464   /* The GPRs are found in the "regs" spufs file.  */
 465   if (regno == -1 || (regno >= 0 && regno < SPU_NUM_CORE_REGS))
 466     {
 467       unsigned char buf[16*SPU_NUM_CORE_REGS];
 468       char annex[32];
 469       int i;
 470
 471       sprintf (annex, "%d/regs", fd);
 472       if (spu_proc_xfer_spu (annex, buf, NULL, 0, sizeof buf) == sizeof buf)
 473         for (i = 0; i < SPU_NUM_CORE_REGS; i++)
 474           supply_register (i, buf + i*16);
 475     }
 476 }
 477
 478 /* Store inferior registers.  */
 479 static void
 480 spu_store_registers (int regno)
 481 {
 482   int fd;
 483   CORE_ADDR addr;
 484
 485   /* ??? Some callers use 0 to mean all registers.  */
 486   if (regno == 0)
 487     regno = -1;
 488
 489   /* We must be stopped on a spu_run system call.  */
 490   if (!parse_spufs_run (&fd, &addr))
 491     return;
 492
 493   /* The NPC register is found at ADDR.  */
 494   if (regno == -1 || regno == SPU_PC_REGNUM)
 495     {
 496       char buf[4];
 497       collect_register (SPU_PC_REGNUM, buf);
 498       store_ppc_memory (addr, buf, 4);
 499     }
 500
 501   /* The GPRs are found in the "regs" spufs file.  */
 502   if (regno == -1 || (regno >= 0 && regno < SPU_NUM_CORE_REGS))
 503     {
 504       unsigned char buf[16*SPU_NUM_CORE_REGS];
 505       char annex[32];
 506       int i;
 507
 508       for (i = 0; i < SPU_NUM_CORE_REGS; i++)
 509         collect_register (i, buf + i*16);
 510
 511       sprintf (annex, "%d/regs", fd);
 512       spu_proc_xfer_spu (annex, NULL, buf, 0, sizeof buf);
 513     }
 514 }
 515
 516 /* Copy LEN bytes from inferior's memory starting at MEMADDR
 517    to debugger memory starting at MYADDR.  */
 518 static int
 519 spu_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
 520 {
 521   int fd, ret;
 522   CORE_ADDR addr;
 523   char annex[32];
 524
 525   /* We must be stopped on a spu_run system call.  */
 526   if (!parse_spufs_run (&fd, &addr))
 527     return 0;
 528
 529   /* Use the "mem" spufs file to access SPU local store.  */
 530   sprintf (annex, "%d/mem", fd);
 531   ret = spu_proc_xfer_spu (annex, myaddr, NULL, memaddr, len);
 532   return ret == len ? 0 : EIO;
 533 }
 534
 535 /* Copy LEN bytes of data from debugger memory at MYADDR
 536    to inferior's memory at MEMADDR.
 537    On failure (cannot write the inferior)
 538    returns the value of errno.  */
 539 static int
 540 spu_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
 541 {
 542   int fd, ret;
 543   CORE_ADDR addr;
 544   char annex[32];
 545
 546   /* We must be stopped on a spu_run system call.  */
 547   if (!parse_spufs_run (&fd, &addr))
 548     return 0;
 549
 550   /* Use the "mem" spufs file to access SPU local store.  */
 551   sprintf (annex, "%d/mem", fd);
 552   ret = spu_proc_xfer_spu (annex, NULL, myaddr, memaddr, len);
 553   return ret == len ? 0 : EIO;
 554 }
 555
 556 /* Look up special symbols -- unneded here.  */
 557 static void
 558 spu_look_up_symbols (void)
 559 {
 560 }
 561
 562 /* Send signal to inferior.  */
 563 static void
 564 spu_request_interrupt (void)
 565 {
 566   syscall (SYS_tkill, current_tid, SIGINT);
 567 }
 568
 569 static struct target_ops spu_target_ops = {
 570   spu_create_inferior,
 571   spu_attach,
 572   spu_kill,
 573   spu_detach,
 574   spu_join,
 575   spu_thread_alive,
 576   spu_resume,
 577   spu_wait,
 578   spu_fetch_registers,
 579   spu_store_registers,
 580   spu_read_memory,
 581   spu_write_memory,
 582   spu_look_up_symbols,
 583   spu_request_interrupt,
 584   NULL,
 585   NULL,
 586   NULL,
 587   NULL,
 588   NULL,
 589   NULL,
 590   NULL,
 591   spu_proc_xfer_spu,
 592   hostio_last_error_from_errno,
 593 };
 594
 595 void
 596 initialize_low (void)
 597 {
 598   static const unsigned char breakpoint[] = { 0x00, 0x00, 0x3f, 0xff };
 599
 600   set_target_ops (&spu_target_ops);
 601   set_breakpoint_data (breakpoint, sizeof breakpoint);
 602   init_registers_spu ();
 603 }