gdb/arm-obsd-tdep.c

   1 /* Target-dependent code for OpenBSD/arm.
   2
   3    Copyright (C) 2006-2024 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 "osabi.h"
  21 #include "trad-frame.h"
  22 #include "tramp-frame.h"
  23
  24 #include "obsd-tdep.h"
  25 #include "arm-tdep.h"
  26 #include "solib-svr4.h"
  27
  28 /* Signal trampolines.  */
  29
  30 static void
  31 armobsd_sigframe_init (const struct tramp_frame *self,
  32                        const frame_info_ptr &this_frame,
  33                        struct trad_frame_cache *cache,
  34                        CORE_ADDR func)
  35 {
  36   CORE_ADDR sp, sigcontext_addr, addr;
  37   int regnum;
  38
  39   /* We find the appropriate instance of `struct sigcontext' at a
  40      fixed offset in the signal frame.  */
  41   sp = get_frame_register_signed (this_frame, ARM_SP_REGNUM);
  42   sigcontext_addr = sp + 16;
  43
  44   /* PC.  */
  45   trad_frame_set_reg_addr (cache, ARM_PC_REGNUM, sigcontext_addr + 76);
  46
  47   /* GPRs.  */
  48   for (regnum = ARM_A1_REGNUM, addr = sigcontext_addr + 12;
  49        regnum <= ARM_LR_REGNUM; regnum++, addr += 4)
  50     trad_frame_set_reg_addr (cache, regnum, addr);
  51
  52   trad_frame_set_id (cache, frame_id_build (sp, func));
  53 }
  54
  55 static const struct tramp_frame armobsd_sigframe =
  56 {
  57   SIGTRAMP_FRAME,
  58   4,
  59   {
  60     { 0xe28d0010, ULONGEST_MAX },               /* add     r0, sp, #16 */
  61     { 0xef000067, ULONGEST_MAX },               /* swi     SYS_sigreturn */
  62     { 0xef000001, ULONGEST_MAX },               /* swi     SYS_exit */
  63     { 0xeafffffc, ULONGEST_MAX },               /* b       . - 8 */
  64     { TRAMP_SENTINEL_INSN, ULONGEST_MAX }
  65   },
  66   armobsd_sigframe_init
  67 };
  68 \f
  69
  70 /* Override default thumb breakpoints.  */
  71 static const gdb_byte arm_obsd_thumb_le_breakpoint[] = {0xfe, 0xdf};
  72 static const gdb_byte arm_obsd_thumb_be_breakpoint[] = {0xdf, 0xfe};
  73
  74 static void
  75 armobsd_init_abi (struct gdbarch_info info,
  76                   struct gdbarch *gdbarch)
  77 {
  78   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
  79
  80   if (tdep->fp_model == ARM_FLOAT_AUTO)
  81     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
  82
  83   tramp_frame_prepend_unwinder (gdbarch, &armobsd_sigframe);
  84
  85   /* OpenBSD/arm uses SVR4-style shared libraries.  */
  86   set_solib_svr4_fetch_link_map_offsets
  87     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
  88   set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
  89
  90   tdep->jb_pc = 24;
  91   tdep->jb_elt_size = 4;
  92
  93   set_gdbarch_iterate_over_regset_sections
  94     (gdbarch, armbsd_iterate_over_regset_sections);
  95
  96   /* OpenBSD/arm uses -fpcc-struct-return by default.  */
  97   tdep->struct_return = pcc_struct_return;
  98
  99   /* Single stepping.  */
 100   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 101
 102   /* Breakpoints.  */
 103   switch (info.byte_order)
 104     {
 105     case BFD_ENDIAN_BIG:
 106       tdep->thumb_breakpoint = arm_obsd_thumb_be_breakpoint;
 107       tdep->thumb_breakpoint_size = sizeof (arm_obsd_thumb_be_breakpoint);
 108       break;
 109
 110     case BFD_ENDIAN_LITTLE:
 111       tdep->thumb_breakpoint = arm_obsd_thumb_le_breakpoint;
 112       tdep->thumb_breakpoint_size = sizeof (arm_obsd_thumb_le_breakpoint);
 113       break;
 114     }
 115 }
 116
 117 void _initialize_armobsd_tdep ();
 118 void
 119 _initialize_armobsd_tdep ()
 120 {
 121   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_OPENBSD,
 122                           armobsd_init_abi);
 123 }