gdb/sparc-linux-tdep.c

   1 /* Target-dependent code for GNU/Linux SPARC.
   2
   3    Copyright (C) 2003, 2004, 2005 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 2 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, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20    Boston, MA 02110-1301, USA.  */
  21
  22 #include "defs.h"
  23 #include "dwarf2-frame.h"
  24 #include "floatformat.h"
  25 #include "frame.h"
  26 #include "frame-unwind.h"
  27 #include "gdbarch.h"
  28 #include "gdbcore.h"
  29 #include "osabi.h"
  30 #include "regcache.h"
  31 #include "solib-svr4.h"
  32 #include "symtab.h"
  33 #include "trad-frame.h"
  34 #include "tramp-frame.h"
  35
  36 #include "sparc-tdep.h"
  37
  38 /* Signal trampoline support.  */
  39
  40 static void sparc32_linux_sigframe_init (const struct tramp_frame *self,
  41                                          struct frame_info *next_frame,
  42                                          struct trad_frame_cache *this_cache,
  43                                          CORE_ADDR func);
  44
  45 /* GNU/Linux has two flavors of signals.  Normal signal handlers, and
  46    "realtime" (RT) signals.  The RT signals can provide additional
  47    information to the signal handler if the SA_SIGINFO flag is set
  48    when establishing a signal handler using `sigaction'.  It is not
  49    unlikely that future versions of GNU/Linux will support SA_SIGINFO
  50    for normal signals too.  */
  51
  52 /* When the sparc Linux kernel calls a signal handler and the
  53    SA_RESTORER flag isn't set, the return address points to a bit of
  54    code on the stack.  This code checks whether the PC appears to be
  55    within this bit of code.
  56
  57    The instruction sequence for normal signals is encoded below.
  58    Checking for the code sequence should be somewhat reliable, because
  59    the effect is to call the system call sigreturn.  This is unlikely
  60    to occur anywhere other than a signal trampoline.  */
  61
  62 static const struct tramp_frame sparc32_linux_sigframe =
  63 {
  64   SIGTRAMP_FRAME,
  65   4,
  66   {
  67     { 0x821020d8, -1 },         /* mov __NR_sugreturn, %g1 */
  68     { 0x91d02010, -1 },         /* ta  0x10 */
  69     { TRAMP_SENTINEL_INSN, -1 }
  70   },
  71   sparc32_linux_sigframe_init
  72 };
  73
  74 /* The instruction sequence for RT signals is slightly different.  The
  75    effect is to call the system call rt_sigreturn.  */
  76
  77 static const struct tramp_frame sparc32_linux_rt_sigframe =
  78 {
  79   SIGTRAMP_FRAME,
  80   4,
  81   {
  82     { 0x82102065, -1 },         /* mov __NR_rt_sigreturn, %g1 */
  83     { 0x91d02010, -1 },         /* ta  0x10 */
  84     { TRAMP_SENTINEL_INSN, -1 }
  85   },
  86   sparc32_linux_sigframe_init
  87 };
  88
  89 static void
  90 sparc32_linux_sigframe_init (const struct tramp_frame *self,
  91                              struct frame_info *next_frame,
  92                              struct trad_frame_cache *this_cache,
  93                              CORE_ADDR func)
  94 {
  95   CORE_ADDR base, addr, sp_addr;
  96   int regnum;
  97
  98   base = frame_unwind_register_unsigned (next_frame, SPARC_O1_REGNUM);
  99   if (self == &sparc32_linux_rt_sigframe)
 100     base += 128;
 101
 102   /* Offsets from <bits/sigcontext.h>.  */
 103
 104   trad_frame_set_reg_addr (this_cache, SPARC32_PSR_REGNUM, base + 0);
 105   trad_frame_set_reg_addr (this_cache, SPARC32_PC_REGNUM, base + 4);
 106   trad_frame_set_reg_addr (this_cache, SPARC32_NPC_REGNUM, base + 8);
 107   trad_frame_set_reg_addr (this_cache, SPARC32_Y_REGNUM, base + 12);
 108
 109   /* Since %g0 is always zero, keep the identity encoding.  */
 110   addr = base + 20;
 111   sp_addr = base + 16 + ((SPARC_SP_REGNUM - SPARC_G0_REGNUM) * 4);
 112   for (regnum = SPARC_G1_REGNUM; regnum <= SPARC_O7_REGNUM; regnum++)
 113     {
 114       trad_frame_set_reg_addr (this_cache, regnum, addr);
 115       addr += 4;
 116     }
 117
 118   base = frame_unwind_register_unsigned (next_frame, SPARC_SP_REGNUM);
 119   addr = get_frame_memory_unsigned (next_frame, sp_addr, 4);
 120
 121   for (regnum = SPARC_L0_REGNUM; regnum <= SPARC_I7_REGNUM; regnum++)
 122     {
 123       trad_frame_set_reg_addr (this_cache, regnum, addr);
 124       addr += 4;
 125     }
 126   trad_frame_set_id (this_cache, frame_id_build (base, func));
 127 }
 128 \f
 129
 130 static void
 131 sparc32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 132 {
 133   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 134
 135   tramp_frame_prepend_unwinder (gdbarch, &sparc32_linux_sigframe);
 136   tramp_frame_prepend_unwinder (gdbarch, &sparc32_linux_rt_sigframe);
 137
 138   /* GNU/Linux has SVR4-style shared libraries...  */
 139   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 140   set_solib_svr4_fetch_link_map_offsets
 141     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 142
 143   /* ...which means that we need some special handling when doing
 144      prologue analysis.  */
 145   tdep->plt_entry_size = 12;
 146
 147   /* GNU/Linux doesn't support the 128-bit `long double' from the psABI.  */
 148   set_gdbarch_long_double_bit (gdbarch, 64);
 149   set_gdbarch_long_double_format (gdbarch, &floatformat_ieee_double_big);
 150
 151   /* Enable TLS support.  */
 152   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 153                                              svr4_fetch_objfile_link_map);
 154
 155   /* Hook in the DWARF CFI frame unwinder.  */
 156   frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer);
 157 }
 158
 159 /* Provide a prototype to silence -Wmissing-prototypes.  */
 160 extern void _initialize_sparc_linux_tdep (void);
 161
 162 void
 163 _initialize_sparc_linux_tdep (void)
 164 {
 165   gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_LINUX,
 166                           sparc32_linux_init_abi);
 167 }