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