gdb/ia64-linux-tdep.c

   1 /* Target-dependent code for the IA-64 for GDB, the GNU debugger.
   2
   3    Copyright (C) 2000, 2004, 2005, 2007, 2008, 2009, 2010, 2011
   4    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 "ia64-tdep.h"
  23 #include "arch-utils.h"
  24 #include "gdbcore.h"
  25 #include "regcache.h"
  26 #include "osabi.h"
  27 #include "solib-svr4.h"
  28 #include "symtab.h"
  29 #include "linux-tdep.h"
  30
  31 /* The sigtramp code is in a non-readable (executable-only) region
  32    of memory called the ``gate page''.  The addresses in question
  33    were determined by examining the system headers.  They are
  34    overly generous to allow for different pages sizes.  */
  35
  36 #define GATE_AREA_START 0xa000000000000100LL
  37 #define GATE_AREA_END   0xa000000000020000LL
  38
  39 /* Offset to sigcontext structure from frame of handler.  */
  40 #define IA64_LINUX_SIGCONTEXT_OFFSET 192
  41
  42 static int
  43 ia64_linux_pc_in_sigtramp (CORE_ADDR pc)
  44 {
  45   return (pc >= (CORE_ADDR) GATE_AREA_START && pc < (CORE_ADDR) GATE_AREA_END);
  46 }
  47
  48 /* IA-64 GNU/Linux specific function which, given a frame address and
  49    a register number, returns the address at which that register may be
  50    found.  0 is returned for registers which aren't stored in the the
  51    sigcontext structure.  */
  52
  53 static CORE_ADDR
  54 ia64_linux_sigcontext_register_address (struct gdbarch *gdbarch,
  55                                         CORE_ADDR sp, int regno)
  56 {
  57   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  58   char buf[8];
  59   CORE_ADDR sigcontext_addr = 0;
  60
  61   /* The address of the sigcontext area is found at offset 16 in the
  62      sigframe.  */
  63   read_memory (sp + 16, buf, 8);
  64   sigcontext_addr = extract_unsigned_integer (buf, 8, byte_order);
  65
  66   if (IA64_GR0_REGNUM <= regno && regno <= IA64_GR31_REGNUM)
  67     return sigcontext_addr + 200 + 8 * (regno - IA64_GR0_REGNUM);
  68   else if (IA64_BR0_REGNUM <= regno && regno <= IA64_BR7_REGNUM)
  69     return sigcontext_addr + 136 + 8 * (regno - IA64_BR0_REGNUM);
  70   else if (IA64_FR0_REGNUM <= regno && regno <= IA64_FR127_REGNUM)
  71     return sigcontext_addr + 464 + 16 * (regno - IA64_FR0_REGNUM);
  72   else
  73     switch (regno)
  74       {
  75       case IA64_IP_REGNUM :
  76         return sigcontext_addr + 40;
  77       case IA64_CFM_REGNUM :
  78         return sigcontext_addr + 48;
  79       case IA64_PSR_REGNUM :
  80         return sigcontext_addr + 56;            /* user mask only */
  81       /* sc_ar_rsc is provided, from which we could compute bspstore, but
  82          I don't think it's worth it.  Anyway, if we want it, it's at offset
  83          64.  */
  84       case IA64_BSP_REGNUM :
  85         return sigcontext_addr + 72;
  86       case IA64_RNAT_REGNUM :
  87         return sigcontext_addr + 80;
  88       case IA64_CCV_REGNUM :
  89         return sigcontext_addr + 88;
  90       case IA64_UNAT_REGNUM :
  91         return sigcontext_addr + 96;
  92       case IA64_FPSR_REGNUM :
  93         return sigcontext_addr + 104;
  94       case IA64_PFS_REGNUM :
  95         return sigcontext_addr + 112;
  96       case IA64_LC_REGNUM :
  97         return sigcontext_addr + 120;
  98       case IA64_PR_REGNUM :
  99         return sigcontext_addr + 128;
 100       default :
 101         return 0;
 102       }
 103 }
 104
 105 static void
 106 ia64_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
 107 {
 108   ia64_write_pc (regcache, pc);
 109
 110   /* We must be careful with modifying the instruction-pointer: if we
 111      just interrupt a system call, the kernel would ordinarily try to
 112      restart it when we resume the inferior, which typically results
 113      in SIGSEGV or SIGILL.  We prevent this by clearing r10, which
 114      will tell the kernel that r8 does NOT contain a valid error code
 115      and hence it will skip system-call restart.
 116
 117      The clearing of r10 is safe as long as ia64_write_pc() is only
 118      called as part of setting up an inferior call.  */
 119   regcache_cooked_write_unsigned (regcache, IA64_GR10_REGNUM, 0);
 120 }
 121
 122 static void
 123 ia64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 124 {
 125   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 126
 127   linux_init_abi (info, gdbarch);
 128
 129   /* Set the method of obtaining the sigcontext addresses at which
 130      registers are saved.  */
 131   tdep->sigcontext_register_address = ia64_linux_sigcontext_register_address;
 132
 133   /* Set the pc_in_sigtramp method.  */
 134   tdep->pc_in_sigtramp = ia64_linux_pc_in_sigtramp;
 135
 136   set_gdbarch_write_pc (gdbarch, ia64_linux_write_pc);
 137
 138   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 139
 140   set_solib_svr4_fetch_link_map_offsets
 141     (gdbarch, svr4_lp64_fetch_link_map_offsets);
 142
 143   /* Enable TLS support.  */
 144   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 145                                              svr4_fetch_objfile_link_map);
 146 }
 147
 148 /* Provide a prototype to silence -Wmissing-prototypes.  */
 149 extern initialize_file_ftype _initialize_ia64_linux_tdep;
 150
 151 void
 152 _initialize_ia64_linux_tdep (void)
 153 {
 154   gdbarch_register_osabi (bfd_arch_ia64, 0, GDB_OSABI_LINUX,
 155                           ia64_linux_init_abi);
 156 }