gdb/ia64-linux-tdep.c

   1 /* Target-dependent code for the IA-64 for GDB, the GNU debugger.
   2
   3    Copyright (C) 2000-2013 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 #include "linux-tdep.h"
  29
  30 /* The sigtramp code is in a non-readable (executable-only) region
  31    of memory called the ``gate page''.  The addresses in question
  32    were determined by examining the system headers.  They are
  33    overly generous to allow for different pages sizes.  */
  34
  35 #define GATE_AREA_START 0xa000000000000100LL
  36 #define GATE_AREA_END   0xa000000000020000LL
  37
  38 /* Offset to sigcontext structure from frame of handler.  */
  39 #define IA64_LINUX_SIGCONTEXT_OFFSET 192
  40
  41 static int
  42 ia64_linux_pc_in_sigtramp (CORE_ADDR pc)
  43 {
  44   return (pc >= (CORE_ADDR) GATE_AREA_START && pc < (CORE_ADDR) GATE_AREA_END);
  45 }
  46
  47 /* IA-64 GNU/Linux specific function which, given a frame address and
  48    a register number, returns the address at which that register may be
  49    found.  0 is returned for registers which aren't stored in the
  50    sigcontext structure.  */
  51
  52 static CORE_ADDR
  53 ia64_linux_sigcontext_register_address (struct gdbarch *gdbarch,
  54                                         CORE_ADDR sp, int regno)
  55 {
  56   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  57   gdb_byte buf[8];
  58   CORE_ADDR sigcontext_addr = 0;
  59
  60   /* The address of the sigcontext area is found at offset 16 in the
  61      sigframe.  */
  62   read_memory (sp + 16, buf, 8);
  63   sigcontext_addr = extract_unsigned_integer (buf, 8, byte_order);
  64
  65   if (IA64_GR0_REGNUM <= regno && regno <= IA64_GR31_REGNUM)
  66     return sigcontext_addr + 200 + 8 * (regno - IA64_GR0_REGNUM);
  67   else if (IA64_BR0_REGNUM <= regno && regno <= IA64_BR7_REGNUM)
  68     return sigcontext_addr + 136 + 8 * (regno - IA64_BR0_REGNUM);
  69   else if (IA64_FR0_REGNUM <= regno && regno <= IA64_FR127_REGNUM)
  70     return sigcontext_addr + 464 + 16 * (regno - IA64_FR0_REGNUM);
  71   else
  72     switch (regno)
  73       {
  74       case IA64_IP_REGNUM :
  75         return sigcontext_addr + 40;
  76       case IA64_CFM_REGNUM :
  77         return sigcontext_addr + 48;
  78       case IA64_PSR_REGNUM :
  79         return sigcontext_addr + 56;            /* user mask only */
  80       /* sc_ar_rsc is provided, from which we could compute bspstore, but
  81          I don't think it's worth it.  Anyway, if we want it, it's at offset
  82          64.  */
  83       case IA64_BSP_REGNUM :
  84         return sigcontext_addr + 72;
  85       case IA64_RNAT_REGNUM :
  86         return sigcontext_addr + 80;
  87       case IA64_CCV_REGNUM :
  88         return sigcontext_addr + 88;
  89       case IA64_UNAT_REGNUM :
  90         return sigcontext_addr + 96;
  91       case IA64_FPSR_REGNUM :
  92         return sigcontext_addr + 104;
  93       case IA64_PFS_REGNUM :
  94         return sigcontext_addr + 112;
  95       case IA64_LC_REGNUM :
  96         return sigcontext_addr + 120;
  97       case IA64_PR_REGNUM :
  98         return sigcontext_addr + 128;
  99       default :
 100         return 0;
 101       }
 102 }
 103
 104 static void
 105 ia64_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
 106 {
 107   ia64_write_pc (regcache, pc);
 108
 109   /* We must be careful with modifying the instruction-pointer: if we
 110      just interrupt a system call, the kernel would ordinarily try to
 111      restart it when we resume the inferior, which typically results
 112      in SIGSEGV or SIGILL.  We prevent this by clearing r10, which
 113      will tell the kernel that r8 does NOT contain a valid error code
 114      and hence it will skip system-call restart.
 115
 116      The clearing of r10 is safe as long as ia64_write_pc() is only
 117      called as part of setting up an inferior call.  */
 118   regcache_cooked_write_unsigned (regcache, IA64_GR10_REGNUM, 0);
 119 }
 120
 121 static void
 122 ia64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 123 {
 124   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 125
 126   linux_init_abi (info, gdbarch);
 127
 128   /* Set the method of obtaining the sigcontext addresses at which
 129      registers are saved.  */
 130   tdep->sigcontext_register_address = ia64_linux_sigcontext_register_address;
 131
 132   /* Set the pc_in_sigtramp method.  */
 133   tdep->pc_in_sigtramp = ia64_linux_pc_in_sigtramp;
 134
 135   set_gdbarch_write_pc (gdbarch, ia64_linux_write_pc);
 136
 137   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 138
 139   set_solib_svr4_fetch_link_map_offsets
 140     (gdbarch, svr4_lp64_fetch_link_map_offsets);
 141
 142   /* Enable TLS support.  */
 143   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 144                                              svr4_fetch_objfile_link_map);
 145 }
 146
 147 /* Provide a prototype to silence -Wmissing-prototypes.  */
 148 extern initialize_file_ftype _initialize_ia64_linux_tdep;
 149
 150 void
 151 _initialize_ia64_linux_tdep (void)
 152 {
 153   gdbarch_register_osabi (bfd_arch_ia64, 0, GDB_OSABI_LINUX,
 154                           ia64_linux_init_abi);
 155 }