gdb/arm-obsd-tdep.c

   1 /* Target-dependent code for OpenBSD/arm.
   2
   3    Copyright (C) 2006-2019 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
  22 /* Local non-gdb includes.  */
  23 #include "arm-tdep.h"
  24 #include "obsd-tdep.h"
  25 #include "osabi.h"
  26 #include "solib-svr4.h"
  27 #include "trad-frame.h"
  28 #include "tramp-frame.h"
  29
  30 /* Signal trampolines.  */
  31
  32 static void
  33 armobsd_sigframe_init (const struct tramp_frame *self,
  34                        struct frame_info *this_frame,
  35                        struct trad_frame_cache *cache,
  36                        CORE_ADDR func)
  37 {
  38   CORE_ADDR sp, sigcontext_addr, addr;
  39   int regnum;
  40
  41   /* We find the appropriate instance of `struct sigcontext' at a
  42      fixed offset in the signal frame.  */
  43   sp = get_frame_register_signed (this_frame, ARM_SP_REGNUM);
  44   sigcontext_addr = sp + 16;
  45
  46   /* PC.  */
  47   trad_frame_set_reg_addr (cache, ARM_PC_REGNUM, sigcontext_addr + 76);
  48
  49   /* GPRs.  */
  50   for (regnum = ARM_A1_REGNUM, addr = sigcontext_addr + 12;
  51        regnum <= ARM_LR_REGNUM; regnum++, addr += 4)
  52     trad_frame_set_reg_addr (cache, regnum, addr);
  53
  54   trad_frame_set_id (cache, frame_id_build (sp, func));
  55 }
  56
  57 static const struct tramp_frame armobsd_sigframe =
  58 {
  59   SIGTRAMP_FRAME,
  60   4,
  61   {
  62     { 0xe28d0010, ULONGEST_MAX },               /* add     r0, sp, #16 */
  63     { 0xef000067, ULONGEST_MAX },               /* swi     SYS_sigreturn */
  64     { 0xef000001, ULONGEST_MAX },               /* swi     SYS_exit */
  65     { 0xeafffffc, ULONGEST_MAX },               /* b       . - 8 */
  66     { TRAMP_SENTINEL_INSN, ULONGEST_MAX }
  67   },
  68   armobsd_sigframe_init
  69 };
  70 \f
  71
  72 /* Override default thumb breakpoints.  */
  73 static const gdb_byte arm_obsd_thumb_le_breakpoint[] = {0xfe, 0xdf};
  74 static const gdb_byte arm_obsd_thumb_be_breakpoint[] = {0xdf, 0xfe};
  75
  76 static void
  77 armobsd_init_abi (struct gdbarch_info info,
  78                   struct gdbarch *gdbarch)
  79 {
  80   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  81
  82   if (tdep->fp_model == ARM_FLOAT_AUTO)
  83     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
  84
  85   tramp_frame_prepend_unwinder (gdbarch, &armobsd_sigframe);
  86
  87   /* OpenBSD/arm uses SVR4-style shared libraries.  */
  88   set_solib_svr4_fetch_link_map_offsets
  89     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
  90   set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
  91
  92   tdep->jb_pc = 24;
  93   tdep->jb_elt_size = 4;
  94
  95   set_gdbarch_iterate_over_regset_sections
  96     (gdbarch, armbsd_iterate_over_regset_sections);
  97
  98   /* OpenBSD/arm uses -fpcc-struct-return by default.  */
  99   tdep->struct_return = pcc_struct_return;
 100
 101   /* Single stepping.  */
 102   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 103
 104   /* Breakpoints.  */
 105   switch (info.byte_order)
 106     {
 107     case BFD_ENDIAN_BIG:
 108       tdep->thumb_breakpoint = arm_obsd_thumb_be_breakpoint;
 109       tdep->thumb_breakpoint_size = sizeof (arm_obsd_thumb_be_breakpoint);
 110       break;
 111
 112     case BFD_ENDIAN_LITTLE:
 113       tdep->thumb_breakpoint = arm_obsd_thumb_le_breakpoint;
 114       tdep->thumb_breakpoint_size = sizeof (arm_obsd_thumb_le_breakpoint);
 115       break;
 116     }
 117 }
 118
 119 void
 120 _initialize_armobsd_tdep (void)
 121 {
 122   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_OPENBSD,
 123                           armobsd_init_abi);
 124 }