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) 2004-2024 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 "gdbcore.h"
  22 #include "target.h"
  23 #include "frame.h"
  24 #include "osabi.h"
  25 #include "regcache.h"
  26 #include "elf-bfd.h"
  27 #include "elf/frv.h"
  28 #include "frv-tdep.h"
  29 #include "trad-frame.h"
  30 #include "frame-unwind.h"
  31 #include "regset.h"
  32 #include "linux-tdep.h"
  33 #include "gdbarch.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 (const frame_info_ptr &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 (_("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 (const frame_info_ptr &this_frame,
 261                                 void **this_cache)
 262 {
 263   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 264   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 265   struct trad_frame_cache *cache;
 266   CORE_ADDR addr;
 267   gdb_byte buf[4];
 268   int regnum;
 269   CORE_ADDR sc_addr_cache_val = 0;
 270   struct frame_id this_id;
 271
 272   if (*this_cache)
 273     return (struct trad_frame_cache *) *this_cache;
 274
 275   cache = trad_frame_cache_zalloc (this_frame);
 276
 277   /* FIXME: cagney/2004-05-01: This is is long standing broken code.
 278      The frame ID's code address should be the start-address of the
 279      signal trampoline and not the current PC within that
 280      trampoline.  */
 281   get_frame_register (this_frame, sp_regnum, buf);
 282   addr = extract_unsigned_integer (buf, sizeof buf, byte_order);
 283   this_id = frame_id_build (addr, get_frame_pc (this_frame));
 284   trad_frame_set_id (cache, this_id);
 285
 286   for (regnum = 0; regnum < frv_num_regs; regnum++)
 287     {
 288       LONGEST reg_addr = frv_linux_sigcontext_reg_addr (this_frame, regnum,
 289                                                         &sc_addr_cache_val);
 290       if (reg_addr != -1)
 291         trad_frame_set_reg_addr (cache, regnum, reg_addr);
 292     }
 293
 294   *this_cache = cache;
 295   return cache;
 296 }
 297
 298 static void
 299 frv_linux_sigtramp_frame_this_id (const frame_info_ptr &this_frame,
 300                                   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 (const frame_info_ptr &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                                   const frame_info_ptr &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   const 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   "frv linux sigtramp",
 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
 418   /* gr0 always contains 0.  Also, the kernel passes the TBR value in
 419      this slot.  */
 420   regcache->raw_supply_zeroed (first_gpr_regnum);
 421
 422   /* Fill gr32, ..., gr63 with zeros. */
 423   for (regi = first_gpr_regnum + 32; regi <= last_gpr_regnum; regi++)
 424     regcache->raw_supply_zeroed (regi);
 425
 426   regcache_supply_regset (regset, regcache, regnum, gregs, len);
 427 }
 428
 429 /* FRV Linux kernel register sets.  */
 430
 431 static const struct regset frv_linux_gregset =
 432 {
 433   frv_linux_gregmap,
 434   frv_linux_supply_gregset, regcache_collect_regset
 435 };
 436
 437 static const struct regset frv_linux_fpregset =
 438 {
 439   frv_linux_fpregmap,
 440   regcache_supply_regset, regcache_collect_regset
 441 };
 442
 443 static void
 444 frv_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 445                                         iterate_over_regset_sections_cb *cb,
 446                                         void *cb_data,
 447                                         const struct regcache *regcache)
 448 {
 449   cb (".reg", sizeof (frv_elf_gregset_t), sizeof (frv_elf_gregset_t),
 450       &frv_linux_gregset, NULL, cb_data);
 451   cb (".reg2", sizeof (frv_elf_fpregset_t), sizeof (frv_elf_fpregset_t),
 452       &frv_linux_fpregset, NULL, cb_data);
 453 }
 454
 455 \f
 456 static void
 457 frv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 458 {
 459   linux_init_abi (info, gdbarch, 0);
 460
 461   /* Set the sigtramp frame sniffer.  */
 462   frame_unwind_append_unwinder (gdbarch, &frv_linux_sigtramp_frame_unwind);
 463
 464   set_gdbarch_iterate_over_regset_sections
 465     (gdbarch, frv_linux_iterate_over_regset_sections);
 466 }
 467
 468 static enum gdb_osabi
 469 frv_linux_elf_osabi_sniffer (bfd *abfd)
 470 {
 471   int elf_flags;
 472
 473   elf_flags = elf_elfheader (abfd)->e_flags;
 474
 475   /* Assume GNU/Linux if using the FDPIC ABI.  If/when another OS shows
 476      up that uses this ABI, we'll need to start using .note sections
 477      or some such.  */
 478   if (elf_flags & EF_FRV_FDPIC)
 479     return GDB_OSABI_LINUX;
 480   else
 481     return GDB_OSABI_UNKNOWN;
 482 }
 483
 484 void _initialize_frv_linux_tdep ();
 485 void
 486 _initialize_frv_linux_tdep ()
 487 {
 488   gdbarch_register_osabi (bfd_arch_frv, 0, GDB_OSABI_LINUX,
 489                           frv_linux_init_abi);
 490   gdbarch_register_osabi_sniffer (bfd_arch_frv,
 491                                   bfd_target_elf_flavour,
 492                                   frv_linux_elf_osabi_sniffer);
 493 }