1 /* Target-dependent code for Windows CE running on ARM processors, 2 for GDB. 3 4 Copyright (C) 2007-2015 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 "arm-tdep.h" 28 #include "windows-tdep.h" 29 30 static const gdb_byte arm_wince_le_breakpoint[] = { 0x10, 0x00, 0x00, 0xe6 }; 31 static const gdb_byte arm_wince_thumb_le_breakpoint[] = { 0xfe, 0xdf }; 32 33 /* Description of the longjmp buffer. */ 34 #define ARM_WINCE_JB_ELEMENT_SIZE INT_REGISTER_SIZE 35 #define ARM_WINCE_JB_PC 10 36 37 static CORE_ADDR 38 arm_pe_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc) 39 { 40 struct gdbarch *gdbarch = get_frame_arch (frame); 41 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 42 ULONGEST indirect; 43 struct bound_minimal_symbol indsym; 44 const char *symname; 45 CORE_ADDR next_pc; 46 47 /* The format of an ARM DLL trampoline is: 48 49 ldr ip, [pc] 50 ldr pc, [ip] 51 .dw __imp_<func> 52 53 */ 54 55 if (pc == 0 56 || read_memory_unsigned_integer (pc + 0, 4, byte_order) != 0xe59fc000 57 || read_memory_unsigned_integer (pc + 4, 4, byte_order) != 0xe59cf000) 58 return 0; 59 60 indirect = read_memory_unsigned_integer (pc + 8, 4, byte_order); 61 if (indirect == 0) 62 return 0; 63 64 indsym = lookup_minimal_symbol_by_pc (indirect); 65 if (indsym.minsym == NULL) 66 return 0; 67 68 symname = MSYMBOL_LINKAGE_NAME (indsym.minsym); 69 if (symname == NULL || !startswith (symname, "__imp_")) 70 return 0; 71 72 next_pc = read_memory_unsigned_integer (indirect, 4, byte_order); 73 if (next_pc != 0) 74 return next_pc; 75 76 /* Check with the default arm gdbarch_skip_trampoline. */ 77 return arm_skip_stub (frame, pc); 78 } 79 80 /* GCC emits a call to __gccmain in the prologue of main. 81 82 The function below examines the code pointed at by PC and checks to 83 see if it corresponds to a call to __gccmain. If so, it returns 84 the address of the instruction following that call. Otherwise, it 85 simply returns PC. */ 86 87 static CORE_ADDR 88 arm_wince_skip_main_prologue (struct gdbarch *gdbarch, CORE_ADDR pc) 89 { 90 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 91 ULONGEST this_instr; 92 93 this_instr = read_memory_unsigned_integer (pc, 4, byte_order); 94 95 /* bl offset <__gccmain> */ 96 if ((this_instr & 0xfff00000) == 0xeb000000) 97 { 98 #define sign_extend(V, N) \ 99 (((long) (V) ^ (1L << ((N) - 1))) - (1L << ((N) - 1))) 100 101 long offset = sign_extend (this_instr & 0x000fffff, 23) << 2; 102 CORE_ADDR call_dest = (pc + 8 + offset) & 0xffffffffU; 103 struct bound_minimal_symbol s = lookup_minimal_symbol_by_pc (call_dest); 104 105 if (s.minsym != NULL 106 && MSYMBOL_LINKAGE_NAME (s.minsym) != NULL 107 && strcmp (MSYMBOL_LINKAGE_NAME (s.minsym), "__gccmain") == 0) 108 pc += 4; 109 } 110 111 return pc; 112 } 113 114 static void 115 arm_wince_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 116 { 117 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 118 119 windows_init_abi (info, gdbarch); 120 121 tdep->arm_breakpoint = arm_wince_le_breakpoint; 122 tdep->arm_breakpoint_size = sizeof (arm_wince_le_breakpoint); 123 tdep->thumb_breakpoint = arm_wince_thumb_le_breakpoint; 124 tdep->thumb_breakpoint_size = sizeof (arm_wince_thumb_le_breakpoint); 125 tdep->struct_return = pcc_struct_return; 126 127 tdep->fp_model = ARM_FLOAT_SOFT_VFP; 128 129 tdep->jb_pc = ARM_WINCE_JB_PC; 130 tdep->jb_elt_size = ARM_WINCE_JB_ELEMENT_SIZE; 131 132 /* On ARM WinCE char defaults to signed. */ 133 set_gdbarch_char_signed (gdbarch, 1); 134 135 /* Shared library handling. */ 136 set_gdbarch_skip_trampoline_code (gdbarch, arm_pe_skip_trampoline_code); 137 138 /* Single stepping. */ 139 set_gdbarch_software_single_step (gdbarch, arm_software_single_step); 140 141 /* Skip call to __gccmain that gcc places in main. */ 142 set_gdbarch_skip_main_prologue (gdbarch, arm_wince_skip_main_prologue); 143 } 144 145 static enum gdb_osabi 146 arm_wince_osabi_sniffer (bfd *abfd) 147 { 148 const char *target_name = bfd_get_target (abfd); 149 150 if (strcmp (target_name, "pei-arm-wince-little") == 0) 151 return GDB_OSABI_WINCE; 152 153 return GDB_OSABI_UNKNOWN; 154 } 155 156 /* Provide a prototype to silence -Wmissing-prototypes. */ 157 void _initialize_arm_wince_tdep (void); 158 159 void 160 _initialize_arm_wince_tdep (void) 161 { 162 gdbarch_register_osabi_sniffer (bfd_arch_arm, bfd_target_coff_flavour, 163 arm_wince_osabi_sniffer); 164 165 gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_WINCE, 166 arm_wince_init_abi); 167 } 168