gdb/frv-linux-tdep.c

   1 /* Target-dependent code for GNU/Linux running on the Fujitsu FR-V,
   2    for GDB.
   3
   4    Copyright (C) 2004, 2006, 2007, 2008, 2009, 2010
   5    Free Software Foundation, Inc.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "gdbcore.h"
  24 #include "target.h"
  25 #include "frame.h"
  26 #include "osabi.h"
  27 #include "regcache.h"
  28 #include "elf-bfd.h"
  29 #include "elf/frv.h"
  30 #include "frv-tdep.h"
  31 #include "trad-frame.h"
  32 #include "frame-unwind.h"
  33 #include "regset.h"
  34 #include "gdb_string.h"
  35 #include "linux-tdep.h"
  36
  37 /* Define the size (in bytes) of an FR-V instruction.  */
  38 static const int frv_instr_size = 4;
  39
  40 enum {
  41   NORMAL_SIGTRAMP = 1,
  42   RT_SIGTRAMP = 2
  43 };
  44
  45 static int
  46 frv_linux_pc_in_sigtramp (struct gdbarch *gdbarch, CORE_ADDR pc, char *name)
  47 {
  48   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  49   char buf[frv_instr_size];
  50   LONGEST instr;
  51   int retval = 0;
  52
  53   if (target_read_memory (pc, buf, sizeof buf) != 0)
  54     return 0;
  55
  56   instr = extract_unsigned_integer (buf, sizeof buf, byte_order);
  57
  58   if (instr == 0x8efc0077)      /* setlos #__NR_sigreturn, gr7 */
  59     retval = NORMAL_SIGTRAMP;
  60   else if (instr -= 0x8efc00ad) /* setlos #__NR_rt_sigreturn, gr7 */
  61     retval = RT_SIGTRAMP;
  62   else
  63     return 0;
  64
  65   if (target_read_memory (pc + frv_instr_size, buf, sizeof buf) != 0)
  66     return 0;
  67   instr = extract_unsigned_integer (buf, sizeof buf, byte_order);
  68   if (instr != 0xc0700000)      /* tira gr0, 0 */
  69     return 0;
  70
  71   /* If we get this far, we'll return a non-zero value, either
  72      NORMAL_SIGTRAMP (1) or RT_SIGTRAMP (2).  */
  73   return retval;
  74 }
  75
  76 /* Given NEXT_FRAME, the "callee" frame of the sigtramp frame that we
  77    wish to decode, and REGNO, one of the frv register numbers defined
  78    in frv-tdep.h, return the address of the saved register (corresponding
  79    to REGNO) in the sigtramp frame.  Return -1 if the register is not
  80    found in the sigtramp frame.  The magic numbers in the code below
  81    were computed by examining the following kernel structs:
  82
  83    From arch/frv/kernel/signal.c:
  84
  85       struct sigframe
  86       {
  87               void (*pretcode)(void);
  88               int sig;
  89               struct sigcontext sc;
  90               unsigned long extramask[_NSIG_WORDS-1];
  91               uint32_t retcode[2];
  92       };
  93
  94       struct rt_sigframe
  95       {
  96               void (*pretcode)(void);
  97               int sig;
  98               struct siginfo *pinfo;
  99               void *puc;
 100               struct siginfo info;
 101               struct ucontext uc;
 102               uint32_t retcode[2];
 103       };
 104
 105    From include/asm-frv/ucontext.h:
 106
 107       struct ucontext {
 108               unsigned long             uc_flags;
 109               struct ucontext           *uc_link;
 110               stack_t                   uc_stack;
 111               struct sigcontext uc_mcontext;
 112               sigset_t          uc_sigmask;
 113       };
 114
 115    From include/asm-frv/signal.h:
 116
 117       typedef struct sigaltstack {
 118               void *ss_sp;
 119               int ss_flags;
 120               size_t ss_size;
 121       } stack_t;
 122
 123    From include/asm-frv/sigcontext.h:
 124
 125       struct sigcontext {
 126               struct user_context       sc_context;
 127               unsigned long             sc_oldmask;
 128       } __attribute__((aligned(8)));
 129
 130    From include/asm-frv/registers.h:
 131       struct user_int_regs
 132       {
 133               unsigned long             psr;
 134               unsigned long             isr;
 135               unsigned long             ccr;
 136               unsigned long             cccr;
 137               unsigned long             lr;
 138               unsigned long             lcr;
 139               unsigned long             pc;
 140               unsigned long             __status;
 141               unsigned long             syscallno;
 142               unsigned long             orig_gr8;
 143               unsigned long             gner[2];
 144               unsigned long long        iacc[1];
 145
 146               union {
 147                       unsigned long     tbr;
 148                       unsigned long     gr[64];
 149               };
 150       };
 151
 152       struct user_fpmedia_regs
 153       {
 154               unsigned long     fr[64];
 155               unsigned long     fner[2];
 156               unsigned long     msr[2];
 157               unsigned long     acc[8];
 158               unsigned char     accg[8];
 159               unsigned long     fsr[1];
 160       };
 161
 162       struct user_context
 163       {
 164               struct user_int_regs              i;
 165               struct user_fpmedia_regs  f;
 166
 167               void *extension;
 168       } __attribute__((aligned(8)));  */
 169
 170 static LONGEST
 171 frv_linux_sigcontext_reg_addr (struct frame_info *this_frame, int regno,
 172                                CORE_ADDR *sc_addr_cache_ptr)
 173 {
 174   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 175   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 176   CORE_ADDR sc_addr;
 177
 178   if (sc_addr_cache_ptr && *sc_addr_cache_ptr)
 179     {
 180       sc_addr = *sc_addr_cache_ptr;
 181     }
 182   else
 183     {
 184       CORE_ADDR pc, sp;
 185       char buf[4];
 186       int tramp_type;
 187
 188       pc = get_frame_pc (this_frame);
 189       tramp_type = frv_linux_pc_in_sigtramp (gdbarch, pc, 0);
 190
 191       get_frame_register (this_frame, sp_regnum, buf);
 192       sp = extract_unsigned_integer (buf, sizeof buf, byte_order);
 193
 194       if (tramp_type == NORMAL_SIGTRAMP)
 195         {
 196           /* For a normal sigtramp frame, the sigcontext struct starts
 197              at SP + 8.  */
 198           sc_addr = sp + 8;
 199         }
 200       else if (tramp_type == RT_SIGTRAMP)
 201         {
 202           /* For a realtime sigtramp frame, SP + 12 contains a pointer
 203              to a ucontext struct.  The ucontext struct contains a
 204              sigcontext struct starting 24 bytes in.  (The offset of
 205              uc_mcontext within struct ucontext is derived as follows:
 206              stack_t is a 12-byte struct and struct sigcontext is
 207              8-byte aligned.  This gives an offset of 8 + 12 + 4 (for
 208              padding) = 24.) */
 209           if (target_read_memory (sp + 12, buf, sizeof buf) != 0)
 210             {
 211               warning (_("Can't read realtime sigtramp frame."));
 212               return 0;
 213             }
 214           sc_addr = extract_unsigned_integer (buf, sizeof buf, byte_order);
 215           sc_addr += 24;
 216         }
 217       else
 218         internal_error (__FILE__, __LINE__, _("not a signal trampoline"));
 219
 220       if (sc_addr_cache_ptr)
 221         *sc_addr_cache_ptr = sc_addr;
 222     }
 223
 224   switch (regno)
 225     {
 226     case psr_regnum :
 227       return sc_addr + 0;
 228     /* sc_addr + 4 has "isr", the Integer Status Register.  */
 229     case ccr_regnum :
 230       return sc_addr + 8;
 231     case cccr_regnum :
 232       return sc_addr + 12;
 233     case lr_regnum :
 234       return sc_addr + 16;
 235     case lcr_regnum :
 236       return sc_addr + 20;
 237     case pc_regnum :
 238       return sc_addr + 24;
 239     /* sc_addr + 28 is __status, the exception status.
 240        sc_addr + 32 is syscallno, the syscall number or -1.
 241        sc_addr + 36 is orig_gr8, the original syscall arg #1.
 242        sc_addr + 40 is gner[0].
 243        sc_addr + 44 is gner[1]. */
 244     case iacc0h_regnum :
 245       return sc_addr + 48;
 246     case iacc0l_regnum :
 247       return sc_addr + 52;
 248     default :
 249       if (first_gpr_regnum <= regno && regno <= last_gpr_regnum)
 250         return sc_addr + 56 + 4 * (regno - first_gpr_regnum);
 251       else if (first_fpr_regnum <= regno && regno <= last_fpr_regnum)
 252         return sc_addr + 312 + 4 * (regno - first_fpr_regnum);
 253       else
 254         return -1;  /* not saved. */
 255     }
 256 }
 257
 258 /* Signal trampolines.  */
 259
 260 static struct trad_frame_cache *
 261 frv_linux_sigtramp_frame_cache (struct frame_info *this_frame, void **this_cache)
 262 {
 263   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 264   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 265   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 266   struct trad_frame_cache *cache;
 267   CORE_ADDR addr;
 268   char buf[4];
 269   int regnum;
 270   CORE_ADDR sc_addr_cache_val = 0;
 271   struct frame_id this_id;
 272
 273   if (*this_cache)
 274     return *this_cache;
 275
 276   cache = trad_frame_cache_zalloc (this_frame);
 277
 278   /* FIXME: cagney/2004-05-01: This is is long standing broken code.
 279      The frame ID's code address should be the start-address of the
 280      signal trampoline and not the current PC within that
 281      trampoline.  */
 282   get_frame_register (this_frame, sp_regnum, buf);
 283   addr = extract_unsigned_integer (buf, sizeof buf, byte_order);
 284   this_id = frame_id_build (addr, get_frame_pc (this_frame));
 285   trad_frame_set_id (cache, this_id);
 286
 287   for (regnum = 0; regnum < frv_num_regs; regnum++)
 288     {
 289       LONGEST reg_addr = frv_linux_sigcontext_reg_addr (this_frame, regnum,
 290                                                         &sc_addr_cache_val);
 291       if (reg_addr != -1)
 292         trad_frame_set_reg_addr (cache, regnum, reg_addr);
 293     }
 294
 295   *this_cache = cache;
 296   return cache;
 297 }
 298
 299 static void
 300 frv_linux_sigtramp_frame_this_id (struct frame_info *this_frame, void **this_cache,
 301                              struct frame_id *this_id)
 302 {
 303   struct trad_frame_cache *cache =
 304     frv_linux_sigtramp_frame_cache (this_frame, this_cache);
 305   trad_frame_get_id (cache, this_id);
 306 }
 307
 308 static struct value *
 309 frv_linux_sigtramp_frame_prev_register (struct frame_info *this_frame,
 310                                         void **this_cache, int regnum)
 311 {
 312   /* Make sure we've initialized the cache.  */
 313   struct trad_frame_cache *cache =
 314     frv_linux_sigtramp_frame_cache (this_frame, this_cache);
 315   return trad_frame_get_register (cache, this_frame, regnum);
 316 }
 317
 318 static int
 319 frv_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
 320                                   struct frame_info *this_frame,
 321                                   void **this_cache)
 322 {
 323   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 324   CORE_ADDR pc = get_frame_pc (this_frame);
 325   char *name;
 326
 327   find_pc_partial_function (pc, &name, NULL, NULL);
 328   if (frv_linux_pc_in_sigtramp (gdbarch, pc, name))
 329     return 1;
 330
 331   return 0;
 332 }
 333
 334 static const struct frame_unwind frv_linux_sigtramp_frame_unwind =
 335 {
 336   SIGTRAMP_FRAME,
 337   frv_linux_sigtramp_frame_this_id,
 338   frv_linux_sigtramp_frame_prev_register,
 339   NULL,
 340   frv_linux_sigtramp_frame_sniffer
 341 };
 342 \f
 343 /* The FRV kernel defines ELF_NGREG as 46.  We add 2 in order to include
 344    the loadmap addresses in the register set.  (See below for more info.)  */
 345 #define FRV_ELF_NGREG (46 + 2)
 346 typedef unsigned char frv_elf_greg_t[4];
 347 typedef struct { frv_elf_greg_t reg[FRV_ELF_NGREG]; } frv_elf_gregset_t;
 348
 349 typedef unsigned char frv_elf_fpreg_t[4];
 350 typedef struct
 351 {
 352   frv_elf_fpreg_t fr[64];
 353   frv_elf_fpreg_t fner[2];
 354   frv_elf_fpreg_t msr[2];
 355   frv_elf_fpreg_t acc[8];
 356   unsigned char accg[8];
 357   frv_elf_fpreg_t fsr[1];
 358 } frv_elf_fpregset_t;
 359
 360 /* Constants for accessing elements of frv_elf_gregset_t.  */
 361
 362 #define FRV_PT_PSR 0
 363 #define FRV_PT_ISR 1
 364 #define FRV_PT_CCR 2
 365 #define FRV_PT_CCCR 3
 366 #define FRV_PT_LR 4
 367 #define FRV_PT_LCR 5
 368 #define FRV_PT_PC 6
 369 #define FRV_PT_GNER0 10
 370 #define FRV_PT_GNER1 11
 371 #define FRV_PT_IACC0H 12
 372 #define FRV_PT_IACC0L 13
 373
 374 /* Note: Only 32 of the GRs will be found in the corefile.  */
 375 #define FRV_PT_GR(j)    ( 14 + (j))     /* GRj for 0<=j<=63. */
 376
 377 #define FRV_PT_TBR FRV_PT_GR(0)         /* gr0 is always 0, so TBR is stuffed
 378                                            there.  */
 379
 380 /* Technically, the loadmap addresses are not part of `pr_reg' as
 381    found in the elf_prstatus struct.  The fields which communicate the
 382    loadmap address appear (by design) immediately after `pr_reg'
 383    though, and the BFD function elf32_frv_grok_prstatus() has been
 384    implemented to include these fields in the register section that it
 385    extracts from the core file.  So, for our purposes, they may be
 386    viewed as registers.  */
 387
 388 #define FRV_PT_EXEC_FDPIC_LOADMAP 46
 389 #define FRV_PT_INTERP_FDPIC_LOADMAP 47
 390
 391
 392 /* Unpack an frv_elf_gregset_t into GDB's register cache.  */
 393
 394 static void
 395 frv_linux_supply_gregset (const struct regset *regset,
 396                           struct regcache *regcache,
 397                           int regnum, const void *gregs, size_t len)
 398 {
 399   int regi;
 400   char zerobuf[MAX_REGISTER_SIZE];
 401   const frv_elf_gregset_t *gregsetp = gregs;
 402
 403   memset (zerobuf, 0, MAX_REGISTER_SIZE);
 404
 405   /* gr0 always contains 0.  Also, the kernel passes the TBR value in
 406      this slot.  */
 407   regcache_raw_supply (regcache, first_gpr_regnum, zerobuf);
 408
 409   for (regi = first_gpr_regnum + 1; regi <= last_gpr_regnum; regi++)
 410     {
 411       if (regi >= first_gpr_regnum + 32)
 412         regcache_raw_supply (regcache, regi, zerobuf);
 413       else
 414         regcache_raw_supply (regcache, regi,
 415                              gregsetp->reg[FRV_PT_GR (regi - first_gpr_regnum)]);
 416     }
 417
 418   regcache_raw_supply (regcache, pc_regnum, gregsetp->reg[FRV_PT_PC]);
 419   regcache_raw_supply (regcache, psr_regnum, gregsetp->reg[FRV_PT_PSR]);
 420   regcache_raw_supply (regcache, ccr_regnum, gregsetp->reg[FRV_PT_CCR]);
 421   regcache_raw_supply (regcache, cccr_regnum, gregsetp->reg[FRV_PT_CCCR]);
 422   regcache_raw_supply (regcache, lr_regnum, gregsetp->reg[FRV_PT_LR]);
 423   regcache_raw_supply (regcache, lcr_regnum, gregsetp->reg[FRV_PT_LCR]);
 424   regcache_raw_supply (regcache, gner0_regnum, gregsetp->reg[FRV_PT_GNER0]);
 425   regcache_raw_supply (regcache, gner1_regnum, gregsetp->reg[FRV_PT_GNER1]);
 426   regcache_raw_supply (regcache, tbr_regnum, gregsetp->reg[FRV_PT_TBR]);
 427   regcache_raw_supply (regcache, fdpic_loadmap_exec_regnum,
 428                        gregsetp->reg[FRV_PT_EXEC_FDPIC_LOADMAP]);
 429   regcache_raw_supply (regcache, fdpic_loadmap_interp_regnum,
 430                        gregsetp->reg[FRV_PT_INTERP_FDPIC_LOADMAP]);
 431 }
 432
 433 /* Unpack an frv_elf_fpregset_t into GDB's register cache.  */
 434
 435 static void
 436 frv_linux_supply_fpregset (const struct regset *regset,
 437                            struct regcache *regcache,
 438                            int regnum, const void *gregs, size_t len)
 439 {
 440   int regi;
 441   const frv_elf_fpregset_t *fpregsetp = gregs;
 442
 443   for (regi = first_fpr_regnum; regi <= last_fpr_regnum; regi++)
 444     regcache_raw_supply (regcache, regi, fpregsetp->fr[regi - first_fpr_regnum]);
 445
 446   regcache_raw_supply (regcache, fner0_regnum, fpregsetp->fner[0]);
 447   regcache_raw_supply (regcache, fner1_regnum, fpregsetp->fner[1]);
 448
 449   regcache_raw_supply (regcache, msr0_regnum, fpregsetp->msr[0]);
 450   regcache_raw_supply (regcache, msr1_regnum, fpregsetp->msr[1]);
 451
 452   for (regi = acc0_regnum; regi <= acc7_regnum; regi++)
 453     regcache_raw_supply (regcache, regi, fpregsetp->acc[regi - acc0_regnum]);
 454
 455   regcache_raw_supply (regcache, accg0123_regnum, fpregsetp->accg);
 456   regcache_raw_supply (regcache, accg4567_regnum, fpregsetp->accg + 4);
 457
 458   regcache_raw_supply (regcache, fsr0_regnum, fpregsetp->fsr[0]);
 459 }
 460
 461 /* FRV Linux kernel register sets.  */
 462
 463 static struct regset frv_linux_gregset =
 464 {
 465   NULL,
 466   frv_linux_supply_gregset
 467 };
 468
 469 static struct regset frv_linux_fpregset =
 470 {
 471   NULL,
 472   frv_linux_supply_fpregset
 473 };
 474
 475 static const struct regset *
 476 frv_linux_regset_from_core_section (struct gdbarch *gdbarch,
 477                                     const char *sect_name, size_t sect_size)
 478 {
 479   if (strcmp (sect_name, ".reg") == 0
 480       && sect_size >= sizeof (frv_elf_gregset_t))
 481     return &frv_linux_gregset;
 482
 483   if (strcmp (sect_name, ".reg2") == 0
 484       && sect_size >= sizeof (frv_elf_fpregset_t))
 485     return &frv_linux_fpregset;
 486
 487   return NULL;
 488 }
 489
 490 \f
 491 static void
 492 frv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 493 {
 494   linux_init_abi (info, gdbarch);
 495
 496   /* Set the sigtramp frame sniffer.  */
 497   frame_unwind_append_unwinder (gdbarch, &frv_linux_sigtramp_frame_unwind);
 498
 499   set_gdbarch_regset_from_core_section (gdbarch,
 500                                         frv_linux_regset_from_core_section);
 501 }
 502
 503 static enum gdb_osabi
 504 frv_linux_elf_osabi_sniffer (bfd *abfd)
 505 {
 506   int elf_flags;
 507
 508   elf_flags = elf_elfheader (abfd)->e_flags;
 509
 510   /* Assume GNU/Linux if using the FDPIC ABI.  If/when another OS shows
 511      up that uses this ABI, we'll need to start using .note sections
 512      or some such.  */
 513   if (elf_flags & EF_FRV_FDPIC)
 514     return GDB_OSABI_LINUX;
 515   else
 516     return GDB_OSABI_UNKNOWN;
 517 }
 518
 519 /* Provide a prototype to silence -Wmissing-prototypes.  */
 520 void _initialize_frv_linux_tdep (void);
 521
 522 void
 523 _initialize_frv_linux_tdep (void)
 524 {
 525   gdbarch_register_osabi (bfd_arch_frv, 0, GDB_OSABI_LINUX, frv_linux_init_abi);
 526   gdbarch_register_osabi_sniffer (bfd_arch_frv,
 527                                   bfd_target_elf_flavour,
 528                                   frv_linux_elf_osabi_sniffer);
 529 }