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