gdb/armobsd-tdep.c

   1 /* Target-dependent code for OpenBSD/arm.
   2
   3    Copyright (C) 2006-2016 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 "osabi.h"
  22 #include "trad-frame.h"
  23 #include "tramp-frame.h"
  24
  25 #include "obsd-tdep.h"
  26 #include "arm-tdep.h"
  27 #include "solib-svr4.h"
  28
  29 /* Signal trampolines.  */
  30
  31 static void
  32 armobsd_sigframe_init (const struct tramp_frame *self,
  33                        struct frame_info *this_frame,
  34                        struct trad_frame_cache *cache,
  35                        CORE_ADDR func)
  36 {
  37   CORE_ADDR sp, sigcontext_addr, addr;
  38   int regnum;
  39
  40   /* We find the appropriate instance of `struct sigcontext' at a
  41      fixed offset in the signal frame.  */
  42   sp = get_frame_register_signed (this_frame, ARM_SP_REGNUM);
  43   sigcontext_addr = sp + 16;
  44
  45   /* PC.  */
  46   trad_frame_set_reg_addr (cache, ARM_PC_REGNUM, sigcontext_addr + 76);
  47
  48   /* GPRs.  */
  49   for (regnum = ARM_A1_REGNUM, addr = sigcontext_addr + 12;
  50        regnum <= ARM_LR_REGNUM; regnum++, addr += 4)
  51     trad_frame_set_reg_addr (cache, regnum, addr);
  52
  53   trad_frame_set_id (cache, frame_id_build (sp, func));
  54 }
  55
  56 static const struct tramp_frame armobsd_sigframe =
  57 {
  58   SIGTRAMP_FRAME,
  59   4,
  60   {
  61     { 0xe28d0010, -1 },         /* add     r0, sp, #16 */
  62     { 0xef000067, -1 },         /* swi     SYS_sigreturn */
  63     { 0xef000001, -1 },         /* swi     SYS_exit */
  64     { 0xeafffffc, -1 },         /* b       . - 8 */
  65     { TRAMP_SENTINEL_INSN, -1 }
  66   },
  67   armobsd_sigframe_init
  68 };
  69 \f
  70
  71 /* Override default thumb breakpoints.  */
  72 static const gdb_byte arm_obsd_thumb_le_breakpoint[] = {0xfe, 0xdf};
  73 static const gdb_byte arm_obsd_thumb_be_breakpoint[] = {0xdf, 0xfe};
  74
  75 static void
  76 armobsd_init_abi (struct gdbarch_info info,
  77                   struct gdbarch *gdbarch)
  78 {
  79   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  80
  81   if (tdep->fp_model == ARM_FLOAT_AUTO)
  82     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
  83
  84   tramp_frame_prepend_unwinder (gdbarch, &armobsd_sigframe);
  85
  86   /* OpenBSD/arm uses SVR4-style shared libraries.  */
  87   set_solib_svr4_fetch_link_map_offsets
  88     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
  89   set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
  90
  91   tdep->jb_pc = 24;
  92   tdep->jb_elt_size = 4;
  93
  94   set_gdbarch_iterate_over_regset_sections
  95     (gdbarch, armbsd_iterate_over_regset_sections);
  96
  97   /* OpenBSD/arm uses -fpcc-struct-return by default.  */
  98   tdep->struct_return = pcc_struct_return;
  99
 100   /* Single stepping.  */
 101   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 102
 103   /* Breakpoints.  */
 104   switch (info.byte_order)
 105     {
 106     case BFD_ENDIAN_BIG:
 107       tdep->thumb_breakpoint = arm_obsd_thumb_be_breakpoint;
 108       tdep->thumb_breakpoint_size = sizeof (arm_obsd_thumb_be_breakpoint);
 109       break;
 110
 111     case BFD_ENDIAN_LITTLE:
 112       tdep->thumb_breakpoint = arm_obsd_thumb_le_breakpoint;
 113       tdep->thumb_breakpoint_size = sizeof (arm_obsd_thumb_le_breakpoint);
 114       break;
 115     }
 116 }
 117 \f
 118
 119 static enum gdb_osabi
 120 armobsd_core_osabi_sniffer (bfd *abfd)
 121 {
 122   if (strcmp (bfd_get_target (abfd), "netbsd-core") == 0)
 123     return GDB_OSABI_OPENBSD_ELF;
 124
 125   return GDB_OSABI_UNKNOWN;
 126 }
 127
 128 /* Provide a prototype to silence -Wmissing-prototypes.  */
 129 extern initialize_file_ftype _initialize_armobsd_tdep;
 130
 131 void
 132 _initialize_armobsd_tdep (void)
 133 {
 134   /* BFD doesn't set a flavour for NetBSD style a.out core files.  */
 135   gdbarch_register_osabi_sniffer (bfd_arch_arm, bfd_target_unknown_flavour,
 136                                   armobsd_core_osabi_sniffer);
 137
 138   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_OPENBSD_ELF,
 139                           armobsd_init_abi);
 140 }