1 /* Target-dependent code for Windows CE running on ARM processors, 2 for GDB. 3 4 Copyright (C) 2007-2017 Free Software Foundation, Inc. 5 6 This file is part of GDB. 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 20 21 #include "defs.h" 22 #include "osabi.h" 23 #include "gdbcore.h" 24 #include "target.h" 25 #include "frame.h" 26 27 #include "arch/arm.h" 28 #include "arm-tdep.h" 29 #include "windows-tdep.h" 30 31 static const gdb_byte arm_wince_le_breakpoint[] = { 0x10, 0x00, 0x00, 0xe6 }; 32 static const gdb_byte arm_wince_thumb_le_breakpoint[] = { 0xfe, 0xdf }; 33 34 /* Description of the longjmp buffer. */ 35 #define ARM_WINCE_JB_ELEMENT_SIZE INT_REGISTER_SIZE 36 #define ARM_WINCE_JB_PC 10 37 38 static CORE_ADDR 39 arm_pe_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc) 40 { 41 struct gdbarch *gdbarch = get_frame_arch (frame); 42 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 43 ULONGEST indirect; 44 struct bound_minimal_symbol indsym; 45 const char *symname; 46 CORE_ADDR next_pc; 47 48 /* The format of an ARM DLL trampoline is: 49 50 ldr ip, [pc] 51 ldr pc, [ip] 52 .dw __imp_<func> 53 54 */ 55 56 if (pc == 0 57 || read_memory_unsigned_integer (pc + 0, 4, byte_order) != 0xe59fc000 58 || read_memory_unsigned_integer (pc + 4, 4, byte_order) != 0xe59cf000) 59 return 0; 60 61 indirect = read_memory_unsigned_integer (pc + 8, 4, byte_order); 62 if (indirect == 0) 63 return 0; 64 65 indsym = lookup_minimal_symbol_by_pc (indirect); 66 if (indsym.minsym == NULL) 67 return 0; 68 69 symname = MSYMBOL_LINKAGE_NAME (indsym.minsym); 70 if (symname == NULL || !startswith (symname, "__imp_")) 71 return 0; 72 73 next_pc = read_memory_unsigned_integer (indirect, 4, byte_order); 74 if (next_pc != 0) 75 return next_pc; 76 77 /* Check with the default arm gdbarch_skip_trampoline. */ 78 return arm_skip_stub (frame, pc); 79 } 80 81 /* GCC emits a call to __gccmain in the prologue of main. 82 83 The function below examines the code pointed at by PC and checks to 84 see if it corresponds to a call to __gccmain. If so, it returns 85 the address of the instruction following that call. Otherwise, it 86 simply returns PC. */ 87 88 static CORE_ADDR 89 arm_wince_skip_main_prologue (struct gdbarch *gdbarch, CORE_ADDR pc) 90 { 91 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 92 ULONGEST this_instr; 93 94 this_instr = read_memory_unsigned_integer (pc, 4, byte_order); 95 96 /* bl offset <__gccmain> */ 97 if ((this_instr & 0xfff00000) == 0xeb000000) 98 { 99 #define sign_extend(V, N) \ 100 (((long) (V) ^ (1L << ((N) - 1))) - (1L << ((N) - 1))) 101 102 long offset = sign_extend (this_instr & 0x000fffff, 23) << 2; 103 CORE_ADDR call_dest = (pc + 8 + offset) & 0xffffffffU; 104 struct bound_minimal_symbol s = lookup_minimal_symbol_by_pc (call_dest); 105 106 if (s.minsym != NULL 107 && MSYMBOL_LINKAGE_NAME (s.minsym) != NULL 108 && strcmp (MSYMBOL_LINKAGE_NAME (s.minsym), "__gccmain") == 0) 109 pc += 4; 110 } 111 112 return pc; 113 } 114 115 static void 116 arm_wince_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 117 { 118 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 119 120 windows_init_abi (info, gdbarch); 121 122 tdep->arm_breakpoint = arm_wince_le_breakpoint; 123 tdep->arm_breakpoint_size = sizeof (arm_wince_le_breakpoint); 124 tdep->thumb_breakpoint = arm_wince_thumb_le_breakpoint; 125 tdep->thumb_breakpoint_size = sizeof (arm_wince_thumb_le_breakpoint); 126 tdep->struct_return = pcc_struct_return; 127 128 tdep->fp_model = ARM_FLOAT_SOFT_VFP; 129 130 tdep->jb_pc = ARM_WINCE_JB_PC; 131 tdep->jb_elt_size = ARM_WINCE_JB_ELEMENT_SIZE; 132 133 /* On ARM WinCE char defaults to signed. */ 134 set_gdbarch_char_signed (gdbarch, 1); 135 136 /* Shared library handling. */ 137 set_gdbarch_skip_trampoline_code (gdbarch, arm_pe_skip_trampoline_code); 138 139 /* Single stepping. */ 140 set_gdbarch_software_single_step (gdbarch, arm_software_single_step); 141 142 /* Skip call to __gccmain that gcc places in main. */ 143 set_gdbarch_skip_main_prologue (gdbarch, arm_wince_skip_main_prologue); 144 } 145 146 static enum gdb_osabi 147 arm_wince_osabi_sniffer (bfd *abfd) 148 { 149 const char *target_name = bfd_get_target (abfd); 150 151 if (strcmp (target_name, "pei-arm-wince-little") == 0) 152 return GDB_OSABI_WINCE; 153 154 return GDB_OSABI_UNKNOWN; 155 } 156 157 /* Provide a prototype to silence -Wmissing-prototypes. */ 158 void _initialize_arm_wince_tdep (void); 159 160 void 161 _initialize_arm_wince_tdep (void) 162 { 163 gdbarch_register_osabi_sniffer (bfd_arch_arm, bfd_target_coff_flavour, 164 arm_wince_osabi_sniffer); 165 166 gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_WINCE, 167 arm_wince_init_abi); 168 } 169