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) 2004-2014 Free Software Foundation, Inc.
   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 "target.h"
  24 #include "frame.h"
  25 #include "osabi.h"
  26 #include "regcache.h"
  27 #include "elf-bfd.h"
  28 #include "elf/frv.h"
  29 #include "frv-tdep.h"
  30 #include "trad-frame.h"
  31 #include "frame-unwind.h"
  32 #include "regset.h"
  33 #include "linux-tdep.h"
  34
  35 /* Define the size (in bytes) of an FR-V instruction.  */
  36 static const int frv_instr_size = 4;
  37
  38 enum {
  39   NORMAL_SIGTRAMP = 1,
  40   RT_SIGTRAMP = 2
  41 };
  42
  43 static int
  44 frv_linux_pc_in_sigtramp (struct gdbarch *gdbarch, CORE_ADDR pc,
  45                           const char *name)
  46 {
  47   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  48   gdb_byte buf[frv_instr_size];
  49   LONGEST instr;
  50   int retval = 0;
  51
  52   if (target_read_memory (pc, buf, sizeof buf) != 0)
  53     return 0;
  54
  55   instr = extract_unsigned_integer (buf, sizeof buf, byte_order);
  56
  57   if (instr == 0x8efc0077)      /* setlos #__NR_sigreturn, gr7 */
  58     retval = NORMAL_SIGTRAMP;
  59   else if (instr == 0x8efc00ad) /* setlos #__NR_rt_sigreturn, gr7 */
  60     retval = RT_SIGTRAMP;
  61   else
  62     return 0;
  63
  64   if (target_read_memory (pc + frv_instr_size, buf, sizeof buf) != 0)
  65     return 0;
  66   instr = extract_unsigned_integer (buf, sizeof buf, byte_order);
  67   if (instr != 0xc0700000)      /* tira gr0, 0 */
  68     return 0;
  69
  70   /* If we get this far, we'll return a non-zero value, either
  71      NORMAL_SIGTRAMP (1) or RT_SIGTRAMP (2).  */
  72   return retval;
  73 }
  74
  75 /* Given NEXT_FRAME, the "callee" frame of the sigtramp frame that we
  76    wish to decode, and REGNO, one of the frv register numbers defined
  77    in frv-tdep.h, return the address of the saved register (corresponding
  78    to REGNO) in the sigtramp frame.  Return -1 if the register is not
  79    found in the sigtramp frame.  The magic numbers in the code below
  80    were computed by examining the following kernel structs:
  81
  82    From arch/frv/kernel/signal.c:
  83
  84       struct sigframe
  85       {
  86               void (*pretcode)(void);
  87               int sig;
  88               struct sigcontext sc;
  89               unsigned long extramask[_NSIG_WORDS-1];
  90               uint32_t retcode[2];
  91       };
  92
  93       struct rt_sigframe
  94       {
  95               void (*pretcode)(void);
  96               int sig;
  97               struct siginfo *pinfo;
  98               void *puc;
  99               struct siginfo info;
 100               struct ucontext uc;
 101               uint32_t retcode[2];
 102       };
 103
 104    From include/asm-frv/ucontext.h:
 105
 106       struct ucontext {
 107               unsigned long             uc_flags;
 108               struct ucontext           *uc_link;
 109               stack_t                   uc_stack;
 110               struct sigcontext uc_mcontext;
 111               sigset_t          uc_sigmask;
 112       };
 113
 114    From include/asm-frv/signal.h:
 115
 116       typedef struct sigaltstack {
 117               void *ss_sp;
 118               int ss_flags;
 119               size_t ss_size;
 120       } stack_t;
 121
 122    From include/asm-frv/sigcontext.h:
 123
 124       struct sigcontext {
 125               struct user_context       sc_context;
 126               unsigned long             sc_oldmask;
 127       } __attribute__((aligned(8)));
 128
 129    From include/asm-frv/registers.h:
 130       struct user_int_regs
 131       {
 132               unsigned long             psr;
 133               unsigned long             isr;
 134               unsigned long             ccr;
 135               unsigned long             cccr;
 136               unsigned long             lr;
 137               unsigned long             lcr;
 138               unsigned long             pc;
 139               unsigned long             __status;
 140               unsigned long             syscallno;
 141               unsigned long             orig_gr8;
 142               unsigned long             gner[2];
 143               unsigned long long        iacc[1];
 144
 145               union {
 146                       unsigned long     tbr;
 147                       unsigned long     gr[64];
 148               };
 149       };
 150
 151       struct user_fpmedia_regs
 152       {
 153               unsigned long     fr[64];
 154               unsigned long     fner[2];
 155               unsigned long     msr[2];
 156               unsigned long     acc[8];
 157               unsigned char     accg[8];
 158               unsigned long     fsr[1];
 159       };
 160
 161       struct user_context
 162       {
 163               struct user_int_regs              i;
 164               struct user_fpmedia_regs  f;
 165
 166               void *extension;
 167       } __attribute__((aligned(8)));  */
 168
 169 static LONGEST
 170 frv_linux_sigcontext_reg_addr (struct frame_info *this_frame, int regno,
 171                                CORE_ADDR *sc_addr_cache_ptr)
 172 {
 173   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 174   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 175   CORE_ADDR sc_addr;
 176
 177   if (sc_addr_cache_ptr && *sc_addr_cache_ptr)
 178     {
 179       sc_addr = *sc_addr_cache_ptr;
 180     }
 181   else
 182     {
 183       CORE_ADDR pc, sp;
 184       gdb_byte buf[4];
 185       int tramp_type;
 186
 187       pc = get_frame_pc (this_frame);
 188       tramp_type = frv_linux_pc_in_sigtramp (gdbarch, pc, 0);
 189
 190       get_frame_register (this_frame, sp_regnum, buf);
 191       sp = extract_unsigned_integer (buf, sizeof buf, byte_order);
 192
 193       if (tramp_type == NORMAL_SIGTRAMP)
 194         {
 195           /* For a normal sigtramp frame, the sigcontext struct starts
 196              at SP + 8.  */
 197           sc_addr = sp + 8;
 198         }
 199       else if (tramp_type == RT_SIGTRAMP)
 200         {
 201           /* For a realtime sigtramp frame, SP + 12 contains a pointer
 202              to a ucontext struct.  The ucontext struct contains a
 203              sigcontext struct starting 24 bytes in.  (The offset of
 204              uc_mcontext within struct ucontext is derived as follows:
 205              stack_t is a 12-byte struct and struct sigcontext is
 206              8-byte aligned.  This gives an offset of 8 + 12 + 4 (for
 207              padding) = 24.)  */
 208           if (target_read_memory (sp + 12, buf, sizeof buf) != 0)
 209             {
 210               warning (_("Can't read realtime sigtramp frame."));
 211               return 0;
 212             }
 213           sc_addr = extract_unsigned_integer (buf, sizeof buf, byte_order);
 214           sc_addr += 24;
 215         }
 216       else
 217         internal_error (__FILE__, __LINE__, _("not a signal trampoline"));
 218
 219       if (sc_addr_cache_ptr)
 220         *sc_addr_cache_ptr = sc_addr;
 221     }
 222
 223   switch (regno)
 224     {
 225     case psr_regnum :
 226       return sc_addr + 0;
 227     /* sc_addr + 4 has "isr", the Integer Status Register.  */
 228     case ccr_regnum :
 229       return sc_addr + 8;
 230     case cccr_regnum :
 231       return sc_addr + 12;
 232     case lr_regnum :
 233       return sc_addr + 16;
 234     case lcr_regnum :
 235       return sc_addr + 20;
 236     case pc_regnum :
 237       return sc_addr + 24;
 238     /* sc_addr + 28 is __status, the exception status.
 239        sc_addr + 32 is syscallno, the syscall number or -1.
 240        sc_addr + 36 is orig_gr8, the original syscall arg #1.
 241        sc_addr + 40 is gner[0].
 242        sc_addr + 44 is gner[1].  */
 243     case iacc0h_regnum :
 244       return sc_addr + 48;
 245     case iacc0l_regnum :
 246       return sc_addr + 52;
 247     default :
 248       if (first_gpr_regnum <= regno && regno <= last_gpr_regnum)
 249         return sc_addr + 56 + 4 * (regno - first_gpr_regnum);
 250       else if (first_fpr_regnum <= regno && regno <= last_fpr_regnum)
 251         return sc_addr + 312 + 4 * (regno - first_fpr_regnum);
 252       else
 253         return -1;  /* not saved.  */
 254     }
 255 }
 256
 257 /* Signal trampolines.  */
 258
 259 static struct trad_frame_cache *
 260 frv_linux_sigtramp_frame_cache (struct frame_info *this_frame,
 261                                 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   gdb_byte 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,
 301                                   void **this_cache,
 302                                   struct frame_id *this_id)
 303 {
 304   struct trad_frame_cache *cache
 305     = frv_linux_sigtramp_frame_cache (this_frame, this_cache);
 306   trad_frame_get_id (cache, this_id);
 307 }
 308
 309 static struct value *
 310 frv_linux_sigtramp_frame_prev_register (struct frame_info *this_frame,
 311                                         void **this_cache, int regnum)
 312 {
 313   /* Make sure we've initialized the cache.  */
 314   struct trad_frame_cache *cache
 315     = frv_linux_sigtramp_frame_cache (this_frame, this_cache);
 316   return trad_frame_get_register (cache, this_frame, regnum);
 317 }
 318
 319 static int
 320 frv_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
 321                                   struct frame_info *this_frame,
 322                                   void **this_cache)
 323 {
 324   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 325   CORE_ADDR pc = get_frame_pc (this_frame);
 326   const char *name;
 327
 328   find_pc_partial_function (pc, &name, NULL, NULL);
 329   if (frv_linux_pc_in_sigtramp (gdbarch, pc, name))
 330     return 1;
 331
 332   return 0;
 333 }
 334
 335 static const struct frame_unwind frv_linux_sigtramp_frame_unwind =
 336 {
 337   SIGTRAMP_FRAME,
 338   default_frame_unwind_stop_reason,
 339   frv_linux_sigtramp_frame_this_id,
 340   frv_linux_sigtramp_frame_prev_register,
 341   NULL,
 342   frv_linux_sigtramp_frame_sniffer
 343 };
 344 \f
 345 /* The FRV kernel defines ELF_NGREG as 46.  We add 2 in order to include
 346    the loadmap addresses in the register set.  (See below for more info.)  */
 347 #define FRV_ELF_NGREG (46 + 2)
 348 typedef unsigned char frv_elf_greg_t[4];
 349 typedef struct { frv_elf_greg_t reg[FRV_ELF_NGREG]; } frv_elf_gregset_t;
 350
 351 typedef unsigned char frv_elf_fpreg_t[4];
 352 typedef struct
 353 {
 354   frv_elf_fpreg_t fr[64];
 355   frv_elf_fpreg_t fner[2];
 356   frv_elf_fpreg_t msr[2];
 357   frv_elf_fpreg_t acc[8];
 358   unsigned char accg[8];
 359   frv_elf_fpreg_t fsr[1];
 360 } frv_elf_fpregset_t;
 361
 362 /* Constants for accessing elements of frv_elf_gregset_t.  */
 363
 364 #define FRV_PT_PSR 0
 365 #define FRV_PT_ISR 1
 366 #define FRV_PT_CCR 2
 367 #define FRV_PT_CCCR 3
 368 #define FRV_PT_LR 4
 369 #define FRV_PT_LCR 5
 370 #define FRV_PT_PC 6
 371 #define FRV_PT_GNER0 10
 372 #define FRV_PT_GNER1 11
 373 #define FRV_PT_IACC0H 12
 374 #define FRV_PT_IACC0L 13
 375
 376 /* Note: Only 32 of the GRs will be found in the corefile.  */
 377 #define FRV_PT_GR(j)    ( 14 + (j))     /* GRj for 0<=j<=63.  */
 378
 379 #define FRV_PT_TBR FRV_PT_GR(0)         /* gr0 is always 0, so TBR is stuffed
 380                                            there.  */
 381
 382 /* Technically, the loadmap addresses are not part of `pr_reg' as
 383    found in the elf_prstatus struct.  The fields which communicate the
 384    loadmap address appear (by design) immediately after `pr_reg'
 385    though, and the BFD function elf32_frv_grok_prstatus() has been
 386    implemented to include these fields in the register section that it
 387    extracts from the core file.  So, for our purposes, they may be
 388    viewed as registers.  */
 389
 390 #define FRV_PT_EXEC_FDPIC_LOADMAP 46
 391 #define FRV_PT_INTERP_FDPIC_LOADMAP 47
 392
 393
 394 /* Unpack an frv_elf_gregset_t into GDB's register cache.  */
 395
 396 static void
 397 frv_linux_supply_gregset (const struct regset *regset,
 398                           struct regcache *regcache,
 399                           int regnum, const void *gregs, size_t len)
 400 {
 401   int regi;
 402   char zerobuf[MAX_REGISTER_SIZE];
 403   const frv_elf_gregset_t *gregsetp = gregs;
 404
 405   memset (zerobuf, 0, MAX_REGISTER_SIZE);
 406
 407   /* gr0 always contains 0.  Also, the kernel passes the TBR value in
 408      this slot.  */
 409   regcache_raw_supply (regcache, first_gpr_regnum, zerobuf);
 410
 411   for (regi = first_gpr_regnum + 1; regi <= last_gpr_regnum; regi++)
 412     {
 413       if (regi >= first_gpr_regnum + 32)
 414         regcache_raw_supply (regcache, regi, zerobuf);
 415       else
 416         regcache_raw_supply (regcache, regi,
 417                              gregsetp->reg[FRV_PT_GR (regi
 418                                                       - first_gpr_regnum)]);
 419     }
 420
 421   regcache_raw_supply (regcache, pc_regnum, gregsetp->reg[FRV_PT_PC]);
 422   regcache_raw_supply (regcache, psr_regnum, gregsetp->reg[FRV_PT_PSR]);
 423   regcache_raw_supply (regcache, ccr_regnum, gregsetp->reg[FRV_PT_CCR]);
 424   regcache_raw_supply (regcache, cccr_regnum, gregsetp->reg[FRV_PT_CCCR]);
 425   regcache_raw_supply (regcache, lr_regnum, gregsetp->reg[FRV_PT_LR]);
 426   regcache_raw_supply (regcache, lcr_regnum, gregsetp->reg[FRV_PT_LCR]);
 427   regcache_raw_supply (regcache, gner0_regnum, gregsetp->reg[FRV_PT_GNER0]);
 428   regcache_raw_supply (regcache, gner1_regnum, gregsetp->reg[FRV_PT_GNER1]);
 429   regcache_raw_supply (regcache, tbr_regnum, gregsetp->reg[FRV_PT_TBR]);
 430   regcache_raw_supply (regcache, fdpic_loadmap_exec_regnum,
 431                        gregsetp->reg[FRV_PT_EXEC_FDPIC_LOADMAP]);
 432   regcache_raw_supply (regcache, fdpic_loadmap_interp_regnum,
 433                        gregsetp->reg[FRV_PT_INTERP_FDPIC_LOADMAP]);
 434 }
 435
 436 /* Unpack an frv_elf_fpregset_t into GDB's register cache.  */
 437
 438 static void
 439 frv_linux_supply_fpregset (const struct regset *regset,
 440                            struct regcache *regcache,
 441                            int regnum, const void *gregs, size_t len)
 442 {
 443   int regi;
 444   const frv_elf_fpregset_t *fpregsetp = gregs;
 445
 446   for (regi = first_fpr_regnum; regi <= last_fpr_regnum; regi++)
 447     regcache_raw_supply (regcache, regi,
 448                          fpregsetp->fr[regi - first_fpr_regnum]);
 449
 450   regcache_raw_supply (regcache, fner0_regnum, fpregsetp->fner[0]);
 451   regcache_raw_supply (regcache, fner1_regnum, fpregsetp->fner[1]);
 452
 453   regcache_raw_supply (regcache, msr0_regnum, fpregsetp->msr[0]);
 454   regcache_raw_supply (regcache, msr1_regnum, fpregsetp->msr[1]);
 455
 456   for (regi = acc0_regnum; regi <= acc7_regnum; regi++)
 457     regcache_raw_supply (regcache, regi, fpregsetp->acc[regi - acc0_regnum]);
 458
 459   regcache_raw_supply (regcache, accg0123_regnum, fpregsetp->accg);
 460   regcache_raw_supply (regcache, accg4567_regnum, fpregsetp->accg + 4);
 461
 462   regcache_raw_supply (regcache, fsr0_regnum, fpregsetp->fsr[0]);
 463 }
 464
 465 /* FRV Linux kernel register sets.  */
 466
 467 static const struct regset frv_linux_gregset =
 468 {
 469   NULL,
 470   frv_linux_supply_gregset
 471 };
 472
 473 static const struct regset frv_linux_fpregset =
 474 {
 475   NULL,
 476   frv_linux_supply_fpregset
 477 };
 478
 479 static const struct regset *
 480 frv_linux_regset_from_core_section (struct gdbarch *gdbarch,
 481                                     const char *sect_name, size_t sect_size)
 482 {
 483   if (strcmp (sect_name, ".reg") == 0
 484       && sect_size >= sizeof (frv_elf_gregset_t))
 485     return &frv_linux_gregset;
 486
 487   if (strcmp (sect_name, ".reg2") == 0
 488       && sect_size >= sizeof (frv_elf_fpregset_t))
 489     return &frv_linux_fpregset;
 490
 491   return NULL;
 492 }
 493
 494 \f
 495 static void
 496 frv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 497 {
 498   linux_init_abi (info, gdbarch);
 499
 500   /* Set the sigtramp frame sniffer.  */
 501   frame_unwind_append_unwinder (gdbarch, &frv_linux_sigtramp_frame_unwind);
 502
 503   set_gdbarch_regset_from_core_section (gdbarch,
 504                                         frv_linux_regset_from_core_section);
 505 }
 506
 507 static enum gdb_osabi
 508 frv_linux_elf_osabi_sniffer (bfd *abfd)
 509 {
 510   int elf_flags;
 511
 512   elf_flags = elf_elfheader (abfd)->e_flags;
 513
 514   /* Assume GNU/Linux if using the FDPIC ABI.  If/when another OS shows
 515      up that uses this ABI, we'll need to start using .note sections
 516      or some such.  */
 517   if (elf_flags & EF_FRV_FDPIC)
 518     return GDB_OSABI_LINUX;
 519   else
 520     return GDB_OSABI_UNKNOWN;
 521 }
 522
 523 /* Provide a prototype to silence -Wmissing-prototypes.  */
 524 void _initialize_frv_linux_tdep (void);
 525
 526 void
 527 _initialize_frv_linux_tdep (void)
 528 {
 529   gdbarch_register_osabi (bfd_arch_frv, 0, GDB_OSABI_LINUX,
 530                           frv_linux_init_abi);
 531   gdbarch_register_osabi_sniffer (bfd_arch_frv,
 532                                   bfd_target_elf_flavour,
 533                                   frv_linux_elf_osabi_sniffer);
 534 }