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 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "ia64-tdep.h"
  22 #include "arch-utils.h"
  23 #include "gdbcore.h"
  24 #include "regcache.h"
  25 #include "osabi.h"
  26 #include "solib-svr4.h"
  27 #include "symtab.h"
  28
  29 /* The sigtramp code is in a non-readable (executable-only) region
  30    of memory called the ``gate page''.  The addresses in question
  31    were determined by examining the system headers.  They are
  32    overly generous to allow for different pages sizes. */
  33
  34 #define GATE_AREA_START 0xa000000000000100LL
  35 #define GATE_AREA_END   0xa000000000020000LL
  36
  37 /* Offset to sigcontext structure from frame of handler */
  38 #define IA64_LINUX_SIGCONTEXT_OFFSET 192
  39
  40 static int
  41 ia64_linux_pc_in_sigtramp (CORE_ADDR pc)
  42 {
  43   return (pc >= (CORE_ADDR) GATE_AREA_START && pc < (CORE_ADDR) GATE_AREA_END);
  44 }
  45
  46 /* IA-64 GNU/Linux specific function which, given a frame address and
  47    a register number, returns the address at which that register may be
  48    found.  0 is returned for registers which aren't stored in the the
  49    sigcontext structure. */
  50
  51 static CORE_ADDR
  52 ia64_linux_sigcontext_register_address (CORE_ADDR sp, int regno)
  53 {
  54   char buf[8];
  55   CORE_ADDR sigcontext_addr = 0;
  56
  57   /* The address of the sigcontext area is found at offset 16 in the sigframe.  */
  58   read_memory (sp + 16, buf, 8);
  59   sigcontext_addr = extract_unsigned_integer (buf, 8);
  60
  61   if (IA64_GR0_REGNUM <= regno && regno <= IA64_GR31_REGNUM)
  62     return sigcontext_addr + 200 + 8 * (regno - IA64_GR0_REGNUM);
  63   else if (IA64_BR0_REGNUM <= regno && regno <= IA64_BR7_REGNUM)
  64     return sigcontext_addr + 136 + 8 * (regno - IA64_BR0_REGNUM);
  65   else if (IA64_FR0_REGNUM <= regno && regno <= IA64_FR127_REGNUM)
  66     return sigcontext_addr + 464 + 16 * (regno - IA64_FR0_REGNUM);
  67   else
  68     switch (regno)
  69       {
  70       case IA64_IP_REGNUM :
  71         return sigcontext_addr + 40;
  72       case IA64_CFM_REGNUM :
  73         return sigcontext_addr + 48;
  74       case IA64_PSR_REGNUM :
  75         return sigcontext_addr + 56;            /* user mask only */
  76       /* sc_ar_rsc is provided, from which we could compute bspstore, but
  77          I don't think it's worth it.  Anyway, if we want it, it's at offset
  78          64 */
  79       case IA64_BSP_REGNUM :
  80         return sigcontext_addr + 72;
  81       case IA64_RNAT_REGNUM :
  82         return sigcontext_addr + 80;
  83       case IA64_CCV_REGNUM :
  84         return sigcontext_addr + 88;
  85       case IA64_UNAT_REGNUM :
  86         return sigcontext_addr + 96;
  87       case IA64_FPSR_REGNUM :
  88         return sigcontext_addr + 104;
  89       case IA64_PFS_REGNUM :
  90         return sigcontext_addr + 112;
  91       case IA64_LC_REGNUM :
  92         return sigcontext_addr + 120;
  93       case IA64_PR_REGNUM :
  94         return sigcontext_addr + 128;
  95       default :
  96         return 0;
  97       }
  98 }
  99
 100 static void
 101 ia64_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
 102 {
 103   ia64_write_pc (regcache, pc);
 104
 105   /* We must be careful with modifying the instruction-pointer: if we
 106      just interrupt a system call, the kernel would ordinarily try to
 107      restart it when we resume the inferior, which typically results
 108      in SIGSEGV or SIGILL.  We prevent this by clearing r10, which
 109      will tell the kernel that r8 does NOT contain a valid error code
 110      and hence it will skip system-call restart.
 111
 112      The clearing of r10 is safe as long as ia64_write_pc() is only
 113      called as part of setting up an inferior call.  */
 114   regcache_cooked_write_unsigned (regcache, IA64_GR10_REGNUM, 0);
 115 }
 116
 117 static void
 118 ia64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 119 {
 120   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 121
 122   /* Set the method of obtaining the sigcontext addresses at which
 123      registers are saved.  */
 124   tdep->sigcontext_register_address = ia64_linux_sigcontext_register_address;
 125
 126   /* Set the pc_in_sigtramp method.  */
 127   tdep->pc_in_sigtramp = ia64_linux_pc_in_sigtramp;
 128
 129   set_gdbarch_write_pc (gdbarch, ia64_linux_write_pc);
 130
 131   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 132
 133   /* Enable TLS support.  */
 134   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 135                                              svr4_fetch_objfile_link_map);
 136 }
 137
 138 void
 139 _initialize_ia64_linux_tdep (void)
 140 {
 141   gdbarch_register_osabi (bfd_arch_ia64, 0, GDB_OSABI_LINUX,
 142                           ia64_linux_init_abi);
 143 }