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 0;
 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       if (errno == ENOENT)
 283         execvp (program, allargs);
 284
 285       fprintf (stderr, "Cannot exec %s: %s.\n", program,
 286                strerror (errno));
 287       fflush (stderr);
 288       _exit (0177);
 289     }
 290
 291   add_thread (pid, NULL, pid);
 292   return pid;
 293 }
 294
 295 /* Attach to an inferior process.  */
 296 int
 297 spu_attach (unsigned long  pid)
 298 {
 299   if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0)
 300     {
 301       fprintf (stderr, "Cannot attach to process %ld: %s (%d)\n", pid,
 302                strerror (errno), errno);
 303       fflush (stderr);
 304       _exit (0177);
 305     }
 306
 307   add_thread (pid, NULL, pid);
 308   return 0;
 309 }
 310
 311 /* Kill the inferior process.  */
 312 static void
 313 spu_kill (void)
 314 {
 315   ptrace (PTRACE_KILL, current_tid, 0, 0);
 316 }
 317
 318 /* Detach from inferior process.  */
 319 static int
 320 spu_detach (void)
 321 {
 322   ptrace (PTRACE_DETACH, current_tid, 0, 0);
 323   return 0;
 324 }
 325
 326 static void
 327 spu_join (void)
 328 {
 329   int status, ret;
 330
 331   do {
 332     ret = waitpid (current_tid, &status, 0);
 333     if (WIFEXITED (status) || WIFSIGNALED (status))
 334       break;
 335   } while (ret != -1 || errno != ECHILD);
 336 }
 337
 338 /* Return nonzero if the given thread is still alive.  */
 339 static int
 340 spu_thread_alive (unsigned long tid)
 341 {
 342   return tid == current_tid;
 343 }
 344
 345 /* Resume process.  */
 346 static void
 347 spu_resume (struct thread_resume *resume_info)
 348 {
 349   while (resume_info->thread != -1
 350          && resume_info->thread != current_tid)
 351     resume_info++;
 352
 353   block_async_io ();
 354   enable_async_io ();
 355
 356   if (resume_info->leave_stopped)
 357     return;
 358
 359   /* We don't support hardware single-stepping right now, assume
 360      GDB knows to use software single-stepping.  */
 361   if (resume_info->step)
 362     fprintf (stderr, "Hardware single-step not supported.\n");
 363
 364   regcache_invalidate ();
 365
 366   errno = 0;
 367   ptrace (PTRACE_CONT, current_tid, 0, resume_info->sig);
 368   if (errno)
 369     perror_with_name ("ptrace");
 370 }
 371
 372 /* Wait for process, returns status.  */
 373 static unsigned char
 374 spu_wait (char *status)
 375 {
 376   int tid = current_tid;
 377   int w;
 378   int ret;
 379
 380   enable_async_io ();
 381   unblock_async_io ();
 382
 383   while (1)
 384     {
 385       ret = waitpid (tid, &w, WNOHANG | __WALL | __WNOTHREAD);
 386
 387       if (ret == -1)
 388         {
 389           if (errno != ECHILD)
 390             perror_with_name ("waitpid");
 391         }
 392       else if (ret > 0)
 393         break;
 394
 395       usleep (1000);
 396     }
 397
 398   /* On the first wait, continue running the inferior until we are
 399      blocked inside an spu_run system call.  */
 400   if (!server_waiting)
 401     {
 402       int fd;
 403       CORE_ADDR addr;
 404
 405       while (!parse_spufs_run (&fd, &addr))
 406         {
 407           ptrace (PT_SYSCALL, tid, (PTRACE_TYPE_ARG3) 0, 0);
 408           waitpid (tid, NULL, __WALL | __WNOTHREAD);
 409         }
 410     }
 411
 412   disable_async_io ();
 413
 414   if (WIFEXITED (w))
 415     {
 416       fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
 417       *status = 'W';
 418       clear_inferiors ();
 419       return ((unsigned char) WEXITSTATUS (w));
 420     }
 421   else if (!WIFSTOPPED (w))
 422     {
 423       fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
 424       *status = 'X';
 425       clear_inferiors ();
 426       return ((unsigned char) WTERMSIG (w));
 427     }
 428
 429   /* After attach, we may have received a SIGSTOP.  Do not return this
 430      as signal to GDB, or else it will try to continue with SIGSTOP ...  */
 431   if (!server_waiting)
 432     {
 433       *status = 'T';
 434       return 0;
 435     }
 436
 437   *status = 'T';
 438   return ((unsigned char) WSTOPSIG (w));
 439 }
 440
 441 /* Fetch inferior registers.  */
 442 static void
 443 spu_fetch_registers (int regno)
 444 {
 445   int fd;
 446   CORE_ADDR addr;
 447
 448   /* ??? Some callers use 0 to mean all registers.  */
 449   if (regno == 0)
 450     regno = -1;
 451
 452   /* We must be stopped on a spu_run system call.  */
 453   if (!parse_spufs_run (&fd, &addr))
 454     return;
 455
 456   /* The ID register holds the spufs file handle.  */
 457   if (regno == -1 || regno == SPU_ID_REGNUM)
 458     supply_register (SPU_ID_REGNUM, (char *)&fd);
 459
 460   /* The NPC register is found at ADDR.  */
 461   if (regno == -1 || regno == SPU_PC_REGNUM)
 462     {
 463       char buf[4];
 464       if (fetch_ppc_memory (addr, buf, 4) == 0)
 465         supply_register (SPU_PC_REGNUM, buf);
 466     }
 467
 468   /* The GPRs are found in the "regs" spufs file.  */
 469   if (regno == -1 || (regno >= 0 && regno < SPU_NUM_CORE_REGS))
 470     {
 471       unsigned char buf[16*SPU_NUM_CORE_REGS];
 472       char annex[32];
 473       int i;
 474
 475       sprintf (annex, "%d/regs", fd);
 476       if (spu_proc_xfer_spu (annex, buf, NULL, 0, sizeof buf) == sizeof buf)
 477         for (i = 0; i < SPU_NUM_CORE_REGS; i++)
 478           supply_register (i, buf + i*16);
 479     }
 480 }
 481
 482 /* Store inferior registers.  */
 483 static void
 484 spu_store_registers (int regno)
 485 {
 486   int fd;
 487   CORE_ADDR addr;
 488
 489   /* ??? Some callers use 0 to mean all registers.  */
 490   if (regno == 0)
 491     regno = -1;
 492
 493   /* We must be stopped on a spu_run system call.  */
 494   if (!parse_spufs_run (&fd, &addr))
 495     return;
 496
 497   /* The NPC register is found at ADDR.  */
 498   if (regno == -1 || regno == SPU_PC_REGNUM)
 499     {
 500       char buf[4];
 501       collect_register (SPU_PC_REGNUM, buf);
 502       store_ppc_memory (addr, buf, 4);
 503     }
 504
 505   /* The GPRs are found in the "regs" spufs file.  */
 506   if (regno == -1 || (regno >= 0 && regno < SPU_NUM_CORE_REGS))
 507     {
 508       unsigned char buf[16*SPU_NUM_CORE_REGS];
 509       char annex[32];
 510       int i;
 511
 512       for (i = 0; i < SPU_NUM_CORE_REGS; i++)
 513         collect_register (i, buf + i*16);
 514
 515       sprintf (annex, "%d/regs", fd);
 516       spu_proc_xfer_spu (annex, NULL, buf, 0, sizeof buf);
 517     }
 518 }
 519
 520 /* Copy LEN bytes from inferior's memory starting at MEMADDR
 521    to debugger memory starting at MYADDR.  */
 522 static int
 523 spu_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
 524 {
 525   int fd, ret;
 526   CORE_ADDR addr;
 527   char annex[32];
 528
 529   /* We must be stopped on a spu_run system call.  */
 530   if (!parse_spufs_run (&fd, &addr))
 531     return 0;
 532
 533   /* Use the "mem" spufs file to access SPU local store.  */
 534   sprintf (annex, "%d/mem", fd);
 535   ret = spu_proc_xfer_spu (annex, myaddr, NULL, memaddr, len);
 536   return ret == len ? 0 : EIO;
 537 }
 538
 539 /* Copy LEN bytes of data from debugger memory at MYADDR
 540    to inferior's memory at MEMADDR.
 541    On failure (cannot write the inferior)
 542    returns the value of errno.  */
 543 static int
 544 spu_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
 545 {
 546   int fd, ret;
 547   CORE_ADDR addr;
 548   char annex[32];
 549
 550   /* We must be stopped on a spu_run system call.  */
 551   if (!parse_spufs_run (&fd, &addr))
 552     return 0;
 553
 554   /* Use the "mem" spufs file to access SPU local store.  */
 555   sprintf (annex, "%d/mem", fd);
 556   ret = spu_proc_xfer_spu (annex, NULL, myaddr, memaddr, len);
 557   return ret == len ? 0 : EIO;
 558 }
 559
 560 /* Look up special symbols -- unneded here.  */
 561 static void
 562 spu_look_up_symbols (void)
 563 {
 564 }
 565
 566 /* Send signal to inferior.  */
 567 static void
 568 spu_request_interrupt (void)
 569 {
 570   syscall (SYS_tkill, current_tid, SIGINT);
 571 }
 572
 573 static const char *
 574 spu_arch_string (void)
 575 {
 576   return "spu";
 577 }
 578
 579 static struct target_ops spu_target_ops = {
 580   spu_create_inferior,
 581   spu_attach,
 582   spu_kill,
 583   spu_detach,
 584   spu_join,
 585   spu_thread_alive,
 586   spu_resume,
 587   spu_wait,
 588   spu_fetch_registers,
 589   spu_store_registers,
 590   spu_read_memory,
 591   spu_write_memory,
 592   spu_look_up_symbols,
 593   spu_request_interrupt,
 594   NULL,
 595   NULL,
 596   NULL,
 597   NULL,
 598   NULL,
 599   NULL,
 600   NULL,
 601   spu_arch_string,
 602   spu_proc_xfer_spu,
 603 };
 604
 605 void
 606 initialize_low (void)
 607 {
 608   static const unsigned char breakpoint[] = { 0x00, 0x00, 0x3f, 0xff };
 609
 610   set_target_ops (&spu_target_ops);
 611   set_breakpoint_data (breakpoint, sizeof breakpoint);
 612   init_registers ();
 613 }