gdb/aarch64-linux-tdep.c

   1 /* Target-dependent code for GNU/Linux AArch64.
   2
   3    Copyright (C) 2009-2015 Free Software Foundation, Inc.
   4    Contributed by ARM Ltd.
   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
  23 #include "gdbarch.h"
  24 #include "glibc-tdep.h"
  25 #include "linux-tdep.h"
  26 #include "aarch64-tdep.h"
  27 #include "aarch64-linux-tdep.h"
  28 #include "osabi.h"
  29 #include "solib-svr4.h"
  30 #include "symtab.h"
  31 #include "tramp-frame.h"
  32 #include "trad-frame.h"
  33
  34 #include "inferior.h"
  35 #include "regcache.h"
  36 #include "regset.h"
  37
  38 #include "cli/cli-utils.h"
  39 #include "stap-probe.h"
  40 #include "parser-defs.h"
  41 #include "user-regs.h"
  42 #include <ctype.h>
  43
  44 /* Signal frame handling.
  45
  46       +------------+  ^
  47       | saved lr   |  |
  48    +->| saved fp   |--+
  49    |  |            |
  50    |  |            |
  51    |  +------------+
  52    |  | saved lr   |
  53    +--| saved fp   |
  54    ^  |            |
  55    |  |            |
  56    |  +------------+
  57    ^  |            |
  58    |  | signal     |
  59    |  |            |        SIGTRAMP_FRAME (struct rt_sigframe)
  60    |  | saved regs |
  61    +--| saved sp   |--> interrupted_sp
  62    |  | saved pc   |--> interrupted_pc
  63    |  |            |
  64    |  +------------+
  65    |  | saved lr   |--> default_restorer (movz x8, NR_sys_rt_sigreturn; svc 0)
  66    +--| saved fp   |<- FP
  67       |            |         NORMAL_FRAME
  68       |            |<- SP
  69       +------------+
  70
  71   On signal delivery, the kernel will create a signal handler stack
  72   frame and setup the return address in LR to point at restorer stub.
  73   The signal stack frame is defined by:
  74
  75   struct rt_sigframe
  76   {
  77     siginfo_t info;
  78     struct ucontext uc;
  79   };
  80
  81   typedef struct
  82   {
  83     ...                                    128 bytes
  84   } siginfo_t;
  85
  86   The ucontext has the following form:
  87   struct ucontext
  88   {
  89     unsigned long uc_flags;
  90     struct ucontext *uc_link;
  91     stack_t uc_stack;
  92     sigset_t uc_sigmask;
  93     struct sigcontext uc_mcontext;
  94   };
  95
  96   typedef struct sigaltstack
  97   {
  98     void *ss_sp;
  99     int ss_flags;
 100     size_t ss_size;
 101   } stack_t;
 102
 103   struct sigcontext
 104   {
 105     unsigned long fault_address;
 106     unsigned long regs[31];
 107     unsigned long sp;           / * 31 * /
 108     unsigned long pc;           / * 32 * /
 109     unsigned long pstate;       / * 33 * /
 110     __u8 __reserved[4096]
 111   };
 112
 113   The restorer stub will always have the form:
 114
 115   d28015a8        movz    x8, #0xad
 116   d4000001        svc     #0x0
 117
 118   This is a system call sys_rt_sigreturn.
 119
 120   We detect signal frames by snooping the return code for the restorer
 121   instruction sequence.
 122
 123   The handler then needs to recover the saved register set from
 124   ucontext.uc_mcontext.  */
 125
 126 /* These magic numbers need to reflect the layout of the kernel
 127    defined struct rt_sigframe and ucontext.  */
 128 #define AARCH64_SIGCONTEXT_REG_SIZE             8
 129 #define AARCH64_RT_SIGFRAME_UCONTEXT_OFFSET     128
 130 #define AARCH64_UCONTEXT_SIGCONTEXT_OFFSET      176
 131 #define AARCH64_SIGCONTEXT_XO_OFFSET            8
 132
 133 /* Implement the "init" method of struct tramp_frame.  */
 134
 135 static void
 136 aarch64_linux_sigframe_init (const struct tramp_frame *self,
 137                              struct frame_info *this_frame,
 138                              struct trad_frame_cache *this_cache,
 139                              CORE_ADDR func)
 140 {
 141   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 142   CORE_ADDR sp = get_frame_register_unsigned (this_frame, AARCH64_SP_REGNUM);
 143   CORE_ADDR sigcontext_addr =
 144     sp
 145     + AARCH64_RT_SIGFRAME_UCONTEXT_OFFSET
 146     + AARCH64_UCONTEXT_SIGCONTEXT_OFFSET;
 147   int i;
 148
 149   for (i = 0; i < 31; i++)
 150     {
 151       trad_frame_set_reg_addr (this_cache,
 152                                AARCH64_X0_REGNUM + i,
 153                                sigcontext_addr + AARCH64_SIGCONTEXT_XO_OFFSET
 154                                + i * AARCH64_SIGCONTEXT_REG_SIZE);
 155     }
 156   trad_frame_set_reg_addr (this_cache, AARCH64_SP_REGNUM,
 157                            sigcontext_addr + AARCH64_SIGCONTEXT_XO_OFFSET
 158                              + 31 * AARCH64_SIGCONTEXT_REG_SIZE);
 159   trad_frame_set_reg_addr (this_cache, AARCH64_PC_REGNUM,
 160                            sigcontext_addr + AARCH64_SIGCONTEXT_XO_OFFSET
 161                              + 32 * AARCH64_SIGCONTEXT_REG_SIZE);
 162
 163   trad_frame_set_id (this_cache, frame_id_build (sp, func));
 164 }
 165
 166 static const struct tramp_frame aarch64_linux_rt_sigframe =
 167 {
 168   SIGTRAMP_FRAME,
 169   4,
 170   {
 171     /* movz x8, 0x8b (S=1,o=10,h=0,i=0x8b,r=8)
 172        Soo1 0010 1hhi iiii iiii iiii iiir rrrr  */
 173     {0xd2801168, -1},
 174
 175     /* svc  0x0      (o=0, l=1)
 176        1101 0100 oooi iiii iiii iiii iii0 00ll  */
 177     {0xd4000001, -1},
 178     {TRAMP_SENTINEL_INSN, -1}
 179   },
 180   aarch64_linux_sigframe_init
 181 };
 182
 183 /* Register maps.  */
 184
 185 static const struct regcache_map_entry aarch64_linux_gregmap[] =
 186   {
 187     { 31, AARCH64_X0_REGNUM, 8 }, /* x0 ... x30 */
 188     { 1, AARCH64_SP_REGNUM, 8 },
 189     { 1, AARCH64_PC_REGNUM, 8 },
 190     { 1, AARCH64_CPSR_REGNUM, 8 },
 191     { 0 }
 192   };
 193
 194 static const struct regcache_map_entry aarch64_linux_fpregmap[] =
 195   {
 196     { 32, AARCH64_V0_REGNUM, 16 }, /* v0 ... v31 */
 197     { 1, AARCH64_FPSR_REGNUM, 4 },
 198     { 1, AARCH64_FPCR_REGNUM, 4 },
 199     { 0 }
 200   };
 201
 202 /* Register set definitions.  */
 203
 204 const struct regset aarch64_linux_gregset =
 205   {
 206     aarch64_linux_gregmap,
 207     regcache_supply_regset, regcache_collect_regset
 208   };
 209
 210 const struct regset aarch64_linux_fpregset =
 211   {
 212     aarch64_linux_fpregmap,
 213     regcache_supply_regset, regcache_collect_regset
 214   };
 215
 216 /* Implement the "regset_from_core_section" gdbarch method.  */
 217
 218 static void
 219 aarch64_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 220                                             iterate_over_regset_sections_cb *cb,
 221                                             void *cb_data,
 222                                             const struct regcache *regcache)
 223 {
 224   cb (".reg", AARCH64_LINUX_SIZEOF_GREGSET, &aarch64_linux_gregset,
 225       NULL, cb_data);
 226   cb (".reg2", AARCH64_LINUX_SIZEOF_FPREGSET, &aarch64_linux_fpregset,
 227       NULL, cb_data);
 228 }
 229
 230 /* Implementation of `gdbarch_stap_is_single_operand', as defined in
 231    gdbarch.h.  */
 232
 233 static int
 234 aarch64_stap_is_single_operand (struct gdbarch *gdbarch, const char *s)
 235 {
 236   return (*s == '#' || isdigit (*s) /* Literal number.  */
 237           || *s == '[' /* Register indirection.  */
 238           || isalpha (*s)); /* Register value.  */
 239 }
 240
 241 /* This routine is used to parse a special token in AArch64's assembly.
 242
 243    The special tokens parsed by it are:
 244
 245       - Register displacement (e.g, [fp, #-8])
 246
 247    It returns one if the special token has been parsed successfully,
 248    or zero if the current token is not considered special.  */
 249
 250 static int
 251 aarch64_stap_parse_special_token (struct gdbarch *gdbarch,
 252                                   struct stap_parse_info *p)
 253 {
 254   if (*p->arg == '[')
 255     {
 256       /* Temporary holder for lookahead.  */
 257       const char *tmp = p->arg;
 258       char *endp;
 259       /* Used to save the register name.  */
 260       const char *start;
 261       char *regname;
 262       int len;
 263       int got_minus = 0;
 264       long displacement;
 265       struct stoken str;
 266
 267       ++tmp;
 268       start = tmp;
 269
 270       /* Register name.  */
 271       while (isalnum (*tmp))
 272         ++tmp;
 273
 274       if (*tmp != ',')
 275         return 0;
 276
 277       len = tmp - start;
 278       regname = alloca (len + 2);
 279
 280       strncpy (regname, start, len);
 281       regname[len] = '\0';
 282
 283       if (user_reg_map_name_to_regnum (gdbarch, regname, len) == -1)
 284         error (_("Invalid register name `%s' on expression `%s'."),
 285                regname, p->saved_arg);
 286
 287       ++tmp;
 288       tmp = skip_spaces_const (tmp);
 289       /* Now we expect a number.  It can begin with '#' or simply
 290          a digit.  */
 291       if (*tmp == '#')
 292         ++tmp;
 293
 294       if (*tmp == '-')
 295         {
 296           ++tmp;
 297           got_minus = 1;
 298         }
 299       else if (*tmp == '+')
 300         ++tmp;
 301
 302       if (!isdigit (*tmp))
 303         return 0;
 304
 305       displacement = strtol (tmp, &endp, 10);
 306       tmp = endp;
 307
 308       /* Skipping last `]'.  */
 309       if (*tmp++ != ']')
 310         return 0;
 311
 312       /* The displacement.  */
 313       write_exp_elt_opcode (&p->pstate, OP_LONG);
 314       write_exp_elt_type (&p->pstate, builtin_type (gdbarch)->builtin_long);
 315       write_exp_elt_longcst (&p->pstate, displacement);
 316       write_exp_elt_opcode (&p->pstate, OP_LONG);
 317       if (got_minus)
 318         write_exp_elt_opcode (&p->pstate, UNOP_NEG);
 319
 320       /* The register name.  */
 321       write_exp_elt_opcode (&p->pstate, OP_REGISTER);
 322       str.ptr = regname;
 323       str.length = len;
 324       write_exp_string (&p->pstate, str);
 325       write_exp_elt_opcode (&p->pstate, OP_REGISTER);
 326
 327       write_exp_elt_opcode (&p->pstate, BINOP_ADD);
 328
 329       /* Casting to the expected type.  */
 330       write_exp_elt_opcode (&p->pstate, UNOP_CAST);
 331       write_exp_elt_type (&p->pstate, lookup_pointer_type (p->arg_type));
 332       write_exp_elt_opcode (&p->pstate, UNOP_CAST);
 333
 334       write_exp_elt_opcode (&p->pstate, UNOP_IND);
 335
 336       p->arg = tmp;
 337     }
 338   else
 339     return 0;
 340
 341   return 1;
 342 }
 343
 344 static void
 345 aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 346 {
 347   static const char *const stap_integer_prefixes[] = { "#", "", NULL };
 348   static const char *const stap_register_prefixes[] = { "", NULL };
 349   static const char *const stap_register_indirection_prefixes[] = { "[",
 350                                                                     NULL };
 351   static const char *const stap_register_indirection_suffixes[] = { "]",
 352                                                                     NULL };
 353   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 354
 355   tdep->lowest_pc = 0x8000;
 356
 357   linux_init_abi (info, gdbarch);
 358
 359   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 360                                          svr4_lp64_fetch_link_map_offsets);
 361
 362   /* Enable TLS support.  */
 363   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 364                                              svr4_fetch_objfile_link_map);
 365
 366   /* Shared library handling.  */
 367   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 368
 369   set_gdbarch_get_siginfo_type (gdbarch, linux_get_siginfo_type);
 370   tramp_frame_prepend_unwinder (gdbarch, &aarch64_linux_rt_sigframe);
 371
 372   /* Enable longjmp.  */
 373   tdep->jb_pc = 11;
 374
 375   set_gdbarch_iterate_over_regset_sections
 376     (gdbarch, aarch64_linux_iterate_over_regset_sections);
 377
 378   /* SystemTap related.  */
 379   set_gdbarch_stap_integer_prefixes (gdbarch, stap_integer_prefixes);
 380   set_gdbarch_stap_register_prefixes (gdbarch, stap_register_prefixes);
 381   set_gdbarch_stap_register_indirection_prefixes (gdbarch,
 382                                             stap_register_indirection_prefixes);
 383   set_gdbarch_stap_register_indirection_suffixes (gdbarch,
 384                                             stap_register_indirection_suffixes);
 385   set_gdbarch_stap_is_single_operand (gdbarch, aarch64_stap_is_single_operand);
 386   set_gdbarch_stap_parse_special_token (gdbarch,
 387                                         aarch64_stap_parse_special_token);
 388 }
 389
 390 /* Provide a prototype to silence -Wmissing-prototypes.  */
 391 extern initialize_file_ftype _initialize_aarch64_linux_tdep;
 392
 393 void
 394 _initialize_aarch64_linux_tdep (void)
 395 {
 396   gdbarch_register_osabi (bfd_arch_aarch64, 0, GDB_OSABI_LINUX,
 397                           aarch64_linux_init_abi);
 398 }