| 1 | /* ARM Symbian OS target support. |
| 2 | |
| 3 | Copyright (C) 2008-2019 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 "defs.h" |
| 21 | #include "frame.h" |
| 22 | #include "objfiles.h" |
| 23 | #include "osabi.h" |
| 24 | #include "solib.h" |
| 25 | #include "solib-target.h" |
| 26 | #include "target.h" |
| 27 | #include "elf-bfd.h" |
| 28 | |
| 29 | /* If PC is in a DLL import stub, return the address of the `real' |
| 30 | function belonging to the stub. */ |
| 31 | |
| 32 | static CORE_ADDR |
| 33 | arm_symbian_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc) |
| 34 | { |
| 35 | struct gdbarch *gdbarch; |
| 36 | enum bfd_endian byte_order; |
| 37 | ULONGEST insn; |
| 38 | CORE_ADDR dest; |
| 39 | gdb_byte buf[4]; |
| 40 | |
| 41 | if (!in_plt_section (pc)) |
| 42 | return 0; |
| 43 | |
| 44 | if (target_read_memory (pc, buf, 4) != 0) |
| 45 | return 0; |
| 46 | |
| 47 | gdbarch = get_frame_arch (frame); |
| 48 | byte_order = gdbarch_byte_order (gdbarch); |
| 49 | |
| 50 | /* ldr pc, [pc, #-4]. */ |
| 51 | insn = extract_unsigned_integer (buf, 4, byte_order); |
| 52 | if (insn != 0xe51ff004) |
| 53 | return 0; |
| 54 | |
| 55 | if (target_read_memory (pc + 4, buf, 4) != 0) |
| 56 | return 0; |
| 57 | |
| 58 | dest = extract_unsigned_integer (buf, 4, byte_order); |
| 59 | return gdbarch_addr_bits_remove (gdbarch, dest); |
| 60 | } |
| 61 | |
| 62 | static void |
| 63 | arm_symbian_init_abi (struct gdbarch_info info, |
| 64 | struct gdbarch *gdbarch) |
| 65 | { |
| 66 | /* Shared library handling. */ |
| 67 | set_gdbarch_skip_trampoline_code (gdbarch, arm_symbian_skip_trampoline_code); |
| 68 | |
| 69 | /* On this target, the toolchain outputs ELF files, with `sym' for |
| 70 | filename extension (e.g., `FOO.sym'); these are post-linker |
| 71 | processed into PE-ish DLLs (e.g., `FOO.dll'), and it's these that |
| 72 | are actually copied to and run on the target. Naturally, when |
| 73 | listing shared libraries, Symbian stubs report the DLL filenames. |
| 74 | Setting this makes it so that GDB automatically looks for the |
| 75 | corresponding ELF files on the host's filesystem. */ |
| 76 | set_gdbarch_solib_symbols_extension (gdbarch, "sym"); |
| 77 | |
| 78 | /* Canonical paths on this target look like `c:\sys\bin\bar.dll', |
| 79 | for example. */ |
| 80 | set_gdbarch_has_dos_based_file_system (gdbarch, 1); |
| 81 | |
| 82 | set_solib_ops (gdbarch, &solib_target_so_ops); |
| 83 | } |
| 84 | |
| 85 | /* Recognize Symbian object files. */ |
| 86 | |
| 87 | static enum gdb_osabi |
| 88 | arm_symbian_osabi_sniffer (bfd *abfd) |
| 89 | { |
| 90 | Elf_Internal_Phdr *phdrs; |
| 91 | long phdrs_size; |
| 92 | int num_phdrs, i; |
| 93 | |
| 94 | /* Symbian executables are always shared objects (ET_DYN). */ |
| 95 | if (elf_elfheader (abfd)->e_type == ET_EXEC) |
| 96 | return GDB_OSABI_UNKNOWN; |
| 97 | |
| 98 | if (elf_elfheader (abfd)->e_ident[EI_OSABI] != ELFOSABI_NONE) |
| 99 | return GDB_OSABI_UNKNOWN; |
| 100 | |
| 101 | /* Check for the ELF headers not being part of any PT_LOAD segment. |
| 102 | Symbian is the only GDB supported (or GNU binutils supported) ARM |
| 103 | target which uses a postlinker to flatten ELF files, dropping the |
| 104 | ELF dynamic info in the process. */ |
| 105 | phdrs_size = bfd_get_elf_phdr_upper_bound (abfd); |
| 106 | if (phdrs_size == -1) |
| 107 | return GDB_OSABI_UNKNOWN; |
| 108 | |
| 109 | phdrs = (Elf_Internal_Phdr *) alloca (phdrs_size); |
| 110 | num_phdrs = bfd_get_elf_phdrs (abfd, phdrs); |
| 111 | if (num_phdrs == -1) |
| 112 | return GDB_OSABI_UNKNOWN; |
| 113 | |
| 114 | for (i = 0; i < num_phdrs; i++) |
| 115 | if (phdrs[i].p_type == PT_LOAD && phdrs[i].p_offset == 0) |
| 116 | return GDB_OSABI_UNKNOWN; |
| 117 | |
| 118 | /* Looks like a Symbian binary. */ |
| 119 | return GDB_OSABI_SYMBIAN; |
| 120 | } |
| 121 | |
| 122 | void |
| 123 | _initialize_arm_symbian_tdep (void) |
| 124 | { |
| 125 | gdbarch_register_osabi_sniffer (bfd_arch_arm, |
| 126 | bfd_target_elf_flavour, |
| 127 | arm_symbian_osabi_sniffer); |
| 128 | |
| 129 | gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_SYMBIAN, |
| 130 | arm_symbian_init_abi); |
| 131 | } |