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      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 
     69 
     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   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_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 
    118 void _initialize_armobsd_tdep ();
    119 void
    120 _initialize_armobsd_tdep ()
    121 {
    122   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_OPENBSD,
    123 			  armobsd_init_abi);
    124 }
    125