| 1 | /* Target-dependent code for Windows CE running on ARM processors, |
| 2 | for GDB. |
| 3 | |
| 4 | Copyright (C) 2007-2019 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 ARM_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 = indsym.minsym->linkage_name (); |
| 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 | && s.minsym->linkage_name () != NULL |
| 108 | && strcmp (s.minsym->linkage_name (), "__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 | void |
| 158 | _initialize_arm_wince_tdep (void) |
| 159 | { |
| 160 | gdbarch_register_osabi_sniffer (bfd_arch_arm, bfd_target_coff_flavour, |
| 161 | arm_wince_osabi_sniffer); |
| 162 | |
| 163 | gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_WINCE, |
| 164 | arm_wince_init_abi); |
| 165 | } |