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) 2004-2016 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 (struct trad_frame_cache *) *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 /* Register maps.  */
 363
 364 static const struct regcache_map_entry frv_linux_gregmap[] =
 365   {
 366     { 1, psr_regnum, 4 },
 367     { 1, REGCACHE_MAP_SKIP, 4 }, /* isr */
 368     { 1, ccr_regnum, 4 },
 369     { 1, cccr_regnum, 4 },
 370     { 1, lr_regnum, 4 },
 371     { 1, lcr_regnum, 4 },
 372     { 1, pc_regnum, 4 },
 373     { 1, REGCACHE_MAP_SKIP, 4 }, /* __status */
 374     { 1, REGCACHE_MAP_SKIP, 4 }, /* syscallno */
 375     { 1, REGCACHE_MAP_SKIP, 4 }, /* orig_gr8 */
 376     { 1, gner0_regnum, 4 },
 377     { 1, gner1_regnum, 4 },
 378     { 1, REGCACHE_MAP_SKIP, 8 }, /* iacc0 */
 379     { 1, tbr_regnum, 4 },
 380     { 31, first_gpr_regnum + 1, 4 }, /* gr1 ... gr31 */
 381
 382     /* Technically, the loadmap addresses are not part of `pr_reg' as
 383        found in the elf_prstatus struct.  The fields which communicate
 384        the loadmap address appear (by design) immediately after
 385        `pr_reg' though, and the BFD function elf32_frv_grok_prstatus()
 386        has been implemented to include these fields in the register
 387        section that it extracts from the core file.  So, for our
 388        purposes, they may be viewed as registers.  */
 389
 390     { 1, fdpic_loadmap_exec_regnum, 4 },
 391     { 1, fdpic_loadmap_interp_regnum, 4 },
 392     { 0 }
 393   };
 394
 395 static const struct regcache_map_entry frv_linux_fpregmap[] =
 396   {
 397     { 64, first_fpr_regnum, 4 }, /* fr0 ... fr63 */
 398     { 1, fner0_regnum, 4 },
 399     { 1, fner1_regnum, 4 },
 400     { 1, msr0_regnum, 4 },
 401     { 1, msr1_regnum, 4 },
 402     { 8, acc0_regnum, 4 },      /* acc0 ... acc7 */
 403     { 1, accg0123_regnum, 4 },
 404     { 1, accg4567_regnum, 4 },
 405     { 1, fsr0_regnum, 4 },
 406     { 0 }
 407   };
 408
 409 /* Unpack an frv_elf_gregset_t into GDB's register cache.  */
 410
 411 static void
 412 frv_linux_supply_gregset (const struct regset *regset,
 413                           struct regcache *regcache,
 414                           int regnum, const void *gregs, size_t len)
 415 {
 416   int regi;
 417   char zerobuf[MAX_REGISTER_SIZE];
 418
 419   memset (zerobuf, 0, MAX_REGISTER_SIZE);
 420
 421   /* gr0 always contains 0.  Also, the kernel passes the TBR value in
 422      this slot.  */
 423   regcache_raw_supply (regcache, first_gpr_regnum, zerobuf);
 424
 425   /* Fill gr32, ..., gr63 with zeros. */
 426   for (regi = first_gpr_regnum + 32; regi <= last_gpr_regnum; regi++)
 427     regcache_raw_supply (regcache, regi, zerobuf);
 428
 429   regcache_supply_regset (regset, regcache, regnum, gregs, len);
 430 }
 431
 432 /* FRV Linux kernel register sets.  */
 433
 434 static const struct regset frv_linux_gregset =
 435 {
 436   frv_linux_gregmap,
 437   frv_linux_supply_gregset, regcache_collect_regset
 438 };
 439
 440 static const struct regset frv_linux_fpregset =
 441 {
 442   frv_linux_fpregmap,
 443   regcache_supply_regset, regcache_collect_regset
 444 };
 445
 446 static void
 447 frv_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 448                                         iterate_over_regset_sections_cb *cb,
 449                                         void *cb_data,
 450                                         const struct regcache *regcache)
 451 {
 452   cb (".reg", sizeof (frv_elf_gregset_t), &frv_linux_gregset,
 453       NULL, cb_data);
 454   cb (".reg2", sizeof (frv_elf_fpregset_t), &frv_linux_fpregset,
 455       NULL, cb_data);
 456 }
 457
 458 \f
 459 static void
 460 frv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 461 {
 462   linux_init_abi (info, gdbarch);
 463
 464   /* Set the sigtramp frame sniffer.  */
 465   frame_unwind_append_unwinder (gdbarch, &frv_linux_sigtramp_frame_unwind);
 466
 467   set_gdbarch_iterate_over_regset_sections
 468     (gdbarch, frv_linux_iterate_over_regset_sections);
 469 }
 470
 471 static enum gdb_osabi
 472 frv_linux_elf_osabi_sniffer (bfd *abfd)
 473 {
 474   int elf_flags;
 475
 476   elf_flags = elf_elfheader (abfd)->e_flags;
 477
 478   /* Assume GNU/Linux if using the FDPIC ABI.  If/when another OS shows
 479      up that uses this ABI, we'll need to start using .note sections
 480      or some such.  */
 481   if (elf_flags & EF_FRV_FDPIC)
 482     return GDB_OSABI_LINUX;
 483   else
 484     return GDB_OSABI_UNKNOWN;
 485 }
 486
 487 /* Provide a prototype to silence -Wmissing-prototypes.  */
 488 void _initialize_frv_linux_tdep (void);
 489
 490 void
 491 _initialize_frv_linux_tdep (void)
 492 {
 493   gdbarch_register_osabi (bfd_arch_frv, 0, GDB_OSABI_LINUX,
 494                           frv_linux_init_abi);
 495   gdbarch_register_osabi_sniffer (bfd_arch_frv,
 496                                   bfd_target_elf_flavour,
 497                                   frv_linux_elf_osabi_sniffer);
 498 }