gdb/ppc-linux-nat.c

   1 /* PPC GNU/Linux native support.
   2    Copyright 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23 #include "frame.h"
  24 #include "inferior.h"
  25 #include "gdbcore.h"
  26 #include "regcache.h"
  27
  28 #include <sys/types.h>
  29 #include <sys/param.h>
  30 #include <signal.h>
  31 #include <sys/user.h>
  32 #include <sys/ioctl.h>
  33 #include <sys/wait.h>
  34 #include <fcntl.h>
  35 #include <sys/procfs.h>
  36 #include <sys/ptrace.h>
  37
  38 /* Prototypes for supply_gregset etc. */
  39 #include "gregset.h"
  40 #include "ppc-tdep.h"
  41
  42 #ifndef PT_READ_U
  43 #define PT_READ_U PTRACE_PEEKUSR
  44 #endif
  45 #ifndef PT_WRITE_U
  46 #define PT_WRITE_U PTRACE_POKEUSR
  47 #endif
  48
  49 /* Default the type of the ptrace transfer to int.  */
  50 #ifndef PTRACE_XFER_TYPE
  51 #define PTRACE_XFER_TYPE int
  52 #endif
  53
  54 /* Glibc's headers don't define PTRACE_GETVRREGS so we cannot use a
  55    configure time check.  Some older glibc's (for instance 2.2.1)
  56    don't have a specific powerpc version of ptrace.h, and fall back on
  57    a generic one.  In such cases, sys/ptrace.h defines
  58    PTRACE_GETFPXREGS and PTRACE_SETFPXREGS to the same numbers that
  59    ppc kernel's asm/ptrace.h defines PTRACE_GETVRREGS and
  60    PTRACE_SETVRREGS to be.  This also makes a configury check pretty
  61    much useless.  */
  62
  63 /* These definitions should really come from the glibc header files,
  64    but Glibc doesn't know about the vrregs yet.  */
  65 #ifndef PTRACE_GETVRREGS
  66 #define PTRACE_GETVRREGS 18
  67 #define PTRACE_SETVRREGS 19
  68 #endif
  69
  70 /* This oddity is because the Linux kernel defines elf_vrregset_t as
  71    an array of 33 16 bytes long elements.  I.e. it leaves out vrsave.
  72    However the PTRACE_GETVRREGS and PTRACE_SETVRREGS requests return
  73    the vrsave as an extra 4 bytes at the end.  I opted for creating a
  74    flat array of chars, so that it is easier to manipulate for gdb.
  75
  76    There are 32 vector registers 16 bytes longs, plus a VSCR register
  77    which is only 4 bytes long, but is fetched as a 16 bytes
  78    quantity. Up to here we have the elf_vrregset_t structure.
  79    Appended to this there is space for the VRSAVE register: 4 bytes.
  80    Even though this vrsave register is not included in the regset
  81    typedef, it is handled by the ptrace requests.
  82
  83    Note that GNU/Linux doesn't support little endian PPC hardware,
  84    therefore the offset at which the real value of the VSCR register
  85    is located will be always 12 bytes.
  86
  87    The layout is like this (where x is the actual value of the vscr reg): */
  88
  89 /* *INDENT-OFF* */
  90 /*
  91    |.|.|.|.|.....|.|.|.|.||.|.|.|x||.|
  92    <------->     <-------><-------><->
  93      VR0           VR31     VSCR    VRSAVE
  94 */
  95 /* *INDENT-ON* */
  96
  97 #define SIZEOF_VRREGS 33*16+4
  98
  99 typedef char gdb_vrregset_t[SIZEOF_VRREGS];
 100
 101 /* For runtime check of ptrace support for VRREGS.  */
 102 int have_ptrace_getvrregs = 1;
 103
 104 int
 105 kernel_u_size (void)
 106 {
 107   return (sizeof (struct user));
 108 }
 109
 110 /* *INDENT-OFF* */
 111 /* registers layout, as presented by the ptrace interface:
 112 PT_R0, PT_R1, PT_R2, PT_R3, PT_R4, PT_R5, PT_R6, PT_R7,
 113 PT_R8, PT_R9, PT_R10, PT_R11, PT_R12, PT_R13, PT_R14, PT_R15,
 114 PT_R16, PT_R17, PT_R18, PT_R19, PT_R20, PT_R21, PT_R22, PT_R23,
 115 PT_R24, PT_R25, PT_R26, PT_R27, PT_R28, PT_R29, PT_R30, PT_R31,
 116 PT_FPR0, PT_FPR0 + 2, PT_FPR0 + 4, PT_FPR0 + 6, PT_FPR0 + 8, PT_FPR0 + 10, PT_FPR0 + 12, PT_FPR0 + 14,
 117 PT_FPR0 + 16, PT_FPR0 + 18, PT_FPR0 + 20, PT_FPR0 + 22, PT_FPR0 + 24, PT_FPR0 + 26, PT_FPR0 + 28, PT_FPR0 + 30,
 118 PT_FPR0 + 32, PT_FPR0 + 34, PT_FPR0 + 36, PT_FPR0 + 38, PT_FPR0 + 40, PT_FPR0 + 42, PT_FPR0 + 44, PT_FPR0 + 46,
 119 PT_FPR0 + 48, PT_FPR0 + 50, PT_FPR0 + 52, PT_FPR0 + 54, PT_FPR0 + 56, PT_FPR0 + 58, PT_FPR0 + 60, PT_FPR0 + 62,
 120 PT_NIP, PT_MSR, PT_CCR, PT_LNK, PT_CTR, PT_XER, PT_MQ */
 121 /* *INDENT_ON * */
 122
 123 static int
 124 ppc_register_u_addr (int regno)
 125 {
 126   int u_addr = -1;
 127   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 128
 129   /* General purpose registers occupy 1 slot each in the buffer */
 130   if (regno >= tdep->ppc_gp0_regnum && regno <= tdep->ppc_gplast_regnum )
 131     u_addr =  ((PT_R0 + regno) * 4);
 132
 133   /* Floating point regs: 2 slots each */
 134   if (regno >= FP0_REGNUM && regno <= FPLAST_REGNUM)
 135     u_addr = ((PT_FPR0 + (regno - FP0_REGNUM) * 2) * 4);
 136
 137   /* UISA special purpose registers: 1 slot each */
 138   if (regno == PC_REGNUM)
 139     u_addr = PT_NIP * 4;
 140   if (regno == tdep->ppc_lr_regnum)
 141     u_addr = PT_LNK * 4;
 142   if (regno == tdep->ppc_cr_regnum)
 143     u_addr = PT_CCR * 4;
 144   if (regno == tdep->ppc_xer_regnum)
 145     u_addr = PT_XER * 4;
 146   if (regno == tdep->ppc_ctr_regnum)
 147     u_addr = PT_CTR * 4;
 148   if (regno == tdep->ppc_mq_regnum)
 149     u_addr = PT_MQ * 4;
 150   if (regno == tdep->ppc_ps_regnum)
 151     u_addr = PT_MSR * 4;
 152   if (regno == tdep->ppc_fpscr_regnum)
 153     u_addr = PT_FPSCR * 4;
 154
 155   return u_addr;
 156 }
 157
 158 static int
 159 ppc_ptrace_cannot_fetch_store_register (int regno)
 160 {
 161   return (ppc_register_u_addr (regno) == -1);
 162 }
 163
 164 /* The Linux kernel ptrace interface for AltiVec registers uses the
 165    registers set mechanism, as opposed to the interface for all the
 166    other registers, that stores/fetches each register individually.  */
 167 static void
 168 fetch_altivec_register (int tid, int regno)
 169 {
 170   int ret;
 171   int offset = 0;
 172   gdb_vrregset_t regs;
 173   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 174   int vrregsize = REGISTER_RAW_SIZE (tdep->ppc_vr0_regnum);
 175
 176   ret = ptrace (PTRACE_GETVRREGS, tid, 0, &regs);
 177   if (ret < 0)
 178     {
 179       if (errno == EIO)
 180         {
 181           have_ptrace_getvrregs = 0;
 182           return;
 183         }
 184       perror_with_name ("Unable to fetch AltiVec register");
 185     }
 186
 187   /* VSCR is fetched as a 16 bytes quantity, but it is really 4 bytes
 188      long on the hardware.  We deal only with the lower 4 bytes of the
 189      vector.  VRSAVE is at the end of the array in a 4 bytes slot, so
 190      there is no need to define an offset for it.  */
 191   if (regno == (tdep->ppc_vrsave_regnum - 1))
 192     offset = vrregsize - REGISTER_RAW_SIZE (tdep->ppc_vrsave_regnum);
 193
 194   supply_register (regno,
 195                    regs + (regno - tdep->ppc_vr0_regnum) * vrregsize + offset);
 196 }
 197
 198 static void
 199 fetch_register (int tid, int regno)
 200 {
 201   /* This isn't really an address.  But ptrace thinks of it as one.  */
 202   char mess[128];              /* For messages */
 203   register int i;
 204   unsigned int offset;         /* Offset of registers within the u area. */
 205   char *buf = alloca (MAX_REGISTER_RAW_SIZE);
 206   CORE_ADDR regaddr = ppc_register_u_addr (regno);
 207
 208   if (altivec_register_p (regno))
 209     {
 210       /* If this is the first time through, or if it is not the first
 211          time through, and we have comfirmed that there is kernel
 212          support for such a ptrace request, then go and fetch the
 213          register.  */
 214       if (have_ptrace_getvrregs)
 215        {
 216          fetch_altivec_register (tid, regno);
 217          return;
 218        }
 219      /* If we have discovered that there is no ptrace support for
 220         AltiVec registers, fall through and return zeroes, because
 221         regaddr will be -1 in this case.  */
 222     }
 223
 224   if (regaddr == -1)
 225     {
 226       memset (buf, '\0', REGISTER_RAW_SIZE (regno));   /* Supply zeroes */
 227       supply_register (regno, buf);
 228       return;
 229     }
 230
 231   for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))
 232     {
 233       errno = 0;
 234       *(PTRACE_XFER_TYPE *) & buf[i] = ptrace (PT_READ_U, tid,
 235                                                (PTRACE_ARG3_TYPE) regaddr, 0);
 236       regaddr += sizeof (PTRACE_XFER_TYPE);
 237       if (errno != 0)
 238         {
 239           sprintf (mess, "reading register %s (#%d)",
 240                    REGISTER_NAME (regno), regno);
 241           perror_with_name (mess);
 242         }
 243     }
 244   supply_register (regno, buf);
 245 }
 246
 247 static void
 248 supply_vrregset (gdb_vrregset_t *vrregsetp)
 249 {
 250   int i;
 251   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 252   int num_of_vrregs = tdep->ppc_vrsave_regnum - tdep->ppc_vr0_regnum + 1;
 253   int vrregsize = REGISTER_RAW_SIZE (tdep->ppc_vr0_regnum);
 254   int offset = vrregsize - REGISTER_RAW_SIZE (tdep->ppc_vrsave_regnum);
 255
 256   for (i = 0; i < num_of_vrregs; i++)
 257     {
 258       /* The last 2 registers of this set are only 32 bit long, not
 259          128.  However an offset is necessary only for VSCR because it
 260          occupies a whole vector, while VRSAVE occupies a full 4 bytes
 261          slot.  */
 262       if (i == (num_of_vrregs - 2))
 263         supply_register (tdep->ppc_vr0_regnum + i,
 264                          *vrregsetp + i * vrregsize + offset);
 265       else
 266         supply_register (tdep->ppc_vr0_regnum + i, *vrregsetp + i * vrregsize);
 267     }
 268 }
 269
 270 static void
 271 fetch_altivec_registers (int tid)
 272 {
 273   int ret;
 274   gdb_vrregset_t regs;
 275
 276   ret = ptrace (PTRACE_GETVRREGS, tid, 0, &regs);
 277   if (ret < 0)
 278     {
 279       if (errno == EIO)
 280         {
 281           have_ptrace_getvrregs = 0;
 282           return;
 283         }
 284       perror_with_name ("Unable to fetch AltiVec registers");
 285     }
 286   supply_vrregset (&regs);
 287 }
 288
 289 static void
 290 fetch_ppc_registers (int tid)
 291 {
 292   int i;
 293   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 294
 295   for (i = 0; i <= tdep->ppc_fpscr_regnum; i++)
 296     fetch_register (tid, i);
 297   if (tdep->ppc_mq_regnum != -1)
 298     fetch_register (tid, tdep->ppc_mq_regnum);
 299   if (have_ptrace_getvrregs)
 300     if (tdep->ppc_vr0_regnum != -1 && tdep->ppc_vrsave_regnum != -1)
 301       fetch_altivec_registers (tid);
 302 }
 303
 304 /* Fetch registers from the child process.  Fetch all registers if
 305    regno == -1, otherwise fetch all general registers or all floating
 306    point registers depending upon the value of regno.  */
 307 void
 308 fetch_inferior_registers (int regno)
 309 {
 310   /* Overload thread id onto process id */
 311   int tid = TIDGET (inferior_ptid);
 312
 313   /* No thread id, just use process id */
 314   if (tid == 0)
 315     tid = PIDGET (inferior_ptid);
 316
 317   if (regno == -1)
 318     fetch_ppc_registers (tid);
 319   else
 320     fetch_register (tid, regno);
 321 }
 322
 323 /* Store one register. */
 324 static void
 325 store_altivec_register (int tid, int regno)
 326 {
 327   int ret;
 328   int offset = 0;
 329   gdb_vrregset_t regs;
 330   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 331   int vrregsize = REGISTER_RAW_SIZE (tdep->ppc_vr0_regnum);
 332
 333   ret = ptrace (PTRACE_GETVRREGS, tid, 0, &regs);
 334   if (ret < 0)
 335     {
 336       if (errno == EIO)
 337         {
 338           have_ptrace_getvrregs = 0;
 339           return;
 340         }
 341       perror_with_name ("Unable to fetch AltiVec register");
 342     }
 343
 344   /* VSCR is fetched as a 16 bytes quantity, but it is really 4 bytes
 345      long on the hardware.  */
 346   if (regno == (tdep->ppc_vrsave_regnum - 1))
 347     offset = vrregsize - REGISTER_RAW_SIZE (tdep->ppc_vrsave_regnum);
 348
 349   regcache_collect (regno,
 350                     regs + (regno - tdep->ppc_vr0_regnum) * vrregsize + offset);
 351
 352   ret = ptrace (PTRACE_SETVRREGS, tid, 0, &regs);
 353   if (ret < 0)
 354     perror_with_name ("Unable to store AltiVec register");
 355 }
 356
 357 static void
 358 store_register (int tid, int regno)
 359 {
 360   /* This isn't really an address.  But ptrace thinks of it as one.  */
 361   CORE_ADDR regaddr = ppc_register_u_addr (regno);
 362   char mess[128];              /* For messages */
 363   register int i;
 364   unsigned int offset;         /* Offset of registers within the u area.  */
 365   char *buf = alloca (MAX_REGISTER_RAW_SIZE);
 366
 367   if (altivec_register_p (regno))
 368     {
 369       store_altivec_register (tid, regno);
 370       return;
 371     }
 372
 373   if (regaddr == -1)
 374     return;
 375
 376   regcache_collect (regno, buf);
 377   for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))
 378     {
 379       errno = 0;
 380       ptrace (PT_WRITE_U, tid, (PTRACE_ARG3_TYPE) regaddr,
 381               *(PTRACE_XFER_TYPE *) & buf[i]);
 382       regaddr += sizeof (PTRACE_XFER_TYPE);
 383
 384       if (errno == EIO
 385           && regno == gdbarch_tdep (current_gdbarch)->ppc_fpscr_regnum)
 386         {
 387           /* Some older kernel versions don't allow fpscr to be written.  */
 388           continue;
 389         }
 390
 391       if (errno != 0)
 392         {
 393           sprintf (mess, "writing register %s (#%d)",
 394                    REGISTER_NAME (regno), regno);
 395           perror_with_name (mess);
 396         }
 397     }
 398 }
 399
 400 static void
 401 fill_vrregset (gdb_vrregset_t *vrregsetp)
 402 {
 403   int i;
 404   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 405   int num_of_vrregs = tdep->ppc_vrsave_regnum - tdep->ppc_vr0_regnum + 1;
 406   int vrregsize = REGISTER_RAW_SIZE (tdep->ppc_vr0_regnum);
 407   int offset = vrregsize - REGISTER_RAW_SIZE (tdep->ppc_vrsave_regnum);
 408
 409   for (i = 0; i < num_of_vrregs; i++)
 410     {
 411       /* The last 2 registers of this set are only 32 bit long, not
 412          128, but only VSCR is fetched as a 16 bytes quantity.  */
 413       if (i == (num_of_vrregs - 2))
 414         regcache_collect (tdep->ppc_vr0_regnum + i,
 415                           *vrregsetp + i * vrregsize + offset);
 416       else
 417         regcache_collect (tdep->ppc_vr0_regnum + i, *vrregsetp + i * vrregsize);
 418     }
 419 }
 420
 421 static void
 422 store_altivec_registers (int tid)
 423 {
 424   int ret;
 425   gdb_vrregset_t regs;
 426
 427   ret = ptrace (PTRACE_GETVRREGS, tid, 0, (int) &regs);
 428   if (ret < 0)
 429     {
 430       if (errno == EIO)
 431         {
 432           have_ptrace_getvrregs = 0;
 433           return;
 434         }
 435       perror_with_name ("Couldn't get AltiVec registers");
 436     }
 437
 438   fill_vrregset (&regs);
 439
 440   if (ptrace (PTRACE_SETVRREGS, tid, 0, (int) &regs) < 0)
 441     perror_with_name ("Couldn't write AltiVec registers");
 442 }
 443
 444 static void
 445 store_ppc_registers (int tid)
 446 {
 447   int i;
 448   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 449
 450   for (i = 0; i <= tdep->ppc_fpscr_regnum; i++)
 451     store_register (tid, i);
 452   if (tdep->ppc_mq_regnum != -1)
 453     store_register (tid, tdep->ppc_mq_regnum);
 454   if (have_ptrace_getvrregs)
 455     if (tdep->ppc_vr0_regnum != -1 && tdep->ppc_vrsave_regnum != -1)
 456       store_altivec_registers (tid);
 457 }
 458
 459 void
 460 store_inferior_registers (int regno)
 461 {
 462   /* Overload thread id onto process id */
 463   int tid = TIDGET (inferior_ptid);
 464
 465   /* No thread id, just use process id */
 466   if (tid == 0)
 467     tid = PIDGET (inferior_ptid);
 468
 469   if (regno >= 0)
 470     store_register (tid, regno);
 471   else
 472     store_ppc_registers (tid);
 473 }
 474
 475 void
 476 supply_gregset (gdb_gregset_t *gregsetp)
 477 {
 478   ppc_linux_supply_gregset ((char *) gregsetp);
 479 }
 480
 481 void
 482 fill_gregset (gdb_gregset_t *gregsetp, int regno)
 483 {
 484   int regi;
 485   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 486   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 487
 488   for (regi = 0; regi < 32; regi++)
 489     {
 490       if ((regno == -1) || regno == regi)
 491         regcache_collect (regi, regp + PT_R0 + regi);
 492     }
 493
 494   if ((regno == -1) || regno == PC_REGNUM)
 495     regcache_collect (PC_REGNUM, regp + PT_NIP);
 496   if ((regno == -1) || regno == tdep->ppc_lr_regnum)
 497     regcache_collect (tdep->ppc_lr_regnum, regp + PT_LNK);
 498   if ((regno == -1) || regno == tdep->ppc_cr_regnum)
 499     regcache_collect (tdep->ppc_cr_regnum, regp + PT_CCR);
 500   if ((regno == -1) || regno == tdep->ppc_xer_regnum)
 501     regcache_collect (tdep->ppc_xer_regnum, regp + PT_XER);
 502   if ((regno == -1) || regno == tdep->ppc_ctr_regnum)
 503     regcache_collect (tdep->ppc_ctr_regnum, regp + PT_CTR);
 504   if (((regno == -1) || regno == tdep->ppc_mq_regnum)
 505       && (tdep->ppc_mq_regnum != -1))
 506     regcache_collect (tdep->ppc_mq_regnum, regp + PT_MQ);
 507   if ((regno == -1) || regno == tdep->ppc_ps_regnum)
 508     regcache_collect (tdep->ppc_ps_regnum, regp + PT_MSR);
 509 }
 510
 511 void
 512 supply_fpregset (gdb_fpregset_t * fpregsetp)
 513 {
 514   ppc_linux_supply_fpregset ((char *) fpregsetp);
 515 }
 516
 517 /* Given a pointer to a floating point register set in /proc format
 518    (fpregset_t *), update the register specified by REGNO from gdb's
 519    idea of the current floating point register set.  If REGNO is -1,
 520    update them all.  */
 521 void
 522 fill_fpregset (gdb_fpregset_t *fpregsetp, int regno)
 523 {
 524   int regi;
 525   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 526
 527   for (regi = 0; regi < 32; regi++)
 528     {
 529       if ((regno == -1) || (regno == FP0_REGNUM + regi))
 530         regcache_collect (FP0_REGNUM + regi, (char *) (*fpregsetp + regi));
 531     }
 532   if ((regno == -1) || regno == tdep->ppc_fpscr_regnum)
 533     regcache_collect (tdep->ppc_fpscr_regnum, (char *) (*fpregsetp + regi));
 534 }