| 1 | /* Target-dependent code for NetBSD/Alpha. |
| 2 | Copyright 2002, 2003 Free Software Foundation, Inc. |
| 3 | Contributed by Wasabi Systems, 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 2 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, write to the Free Software |
| 19 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 20 | Boston, MA 02111-1307, USA. */ |
| 21 | |
| 22 | #include "defs.h" |
| 23 | #include "gdbcore.h" |
| 24 | #include "frame.h" |
| 25 | #include "regcache.h" |
| 26 | #include "value.h" |
| 27 | #include "osabi.h" |
| 28 | |
| 29 | #include "solib-svr4.h" |
| 30 | |
| 31 | #include "alpha-tdep.h" |
| 32 | #include "alphabsd-tdep.h" |
| 33 | #include "nbsd-tdep.h" |
| 34 | |
| 35 | static void |
| 36 | fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which, |
| 37 | CORE_ADDR ignore) |
| 38 | { |
| 39 | char *regs, *fpregs; |
| 40 | int regno; |
| 41 | |
| 42 | /* Table to map a gdb register number to a trapframe register index. */ |
| 43 | static const int regmap[] = |
| 44 | { |
| 45 | 0, 1, 2, 3, |
| 46 | 4, 5, 6, 7, |
| 47 | 8, 9, 10, 11, |
| 48 | 12, 13, 14, 15, |
| 49 | 30, 31, 32, 16, |
| 50 | 17, 18, 19, 20, |
| 51 | 21, 22, 23, 24, |
| 52 | 25, 29, 26 |
| 53 | }; |
| 54 | #define SIZEOF_TRAPFRAME (33 * 8) |
| 55 | |
| 56 | /* We get everything from one section. */ |
| 57 | if (which != 0) |
| 58 | return; |
| 59 | |
| 60 | regs = core_reg_sect; |
| 61 | fpregs = core_reg_sect + SIZEOF_TRAPFRAME; |
| 62 | |
| 63 | if (core_reg_size < (SIZEOF_TRAPFRAME + SIZEOF_STRUCT_FPREG)) |
| 64 | { |
| 65 | warning ("Wrong size register set in core file."); |
| 66 | return; |
| 67 | } |
| 68 | |
| 69 | /* Integer registers. */ |
| 70 | for (regno = 0; regno < ALPHA_ZERO_REGNUM; regno++) |
| 71 | supply_register (regno, regs + (regmap[regno] * 8)); |
| 72 | supply_register (ALPHA_ZERO_REGNUM, NULL); |
| 73 | supply_register (DEPRECATED_FP_REGNUM, NULL); |
| 74 | supply_register (PC_REGNUM, regs + (28 * 8)); |
| 75 | |
| 76 | /* Floating point registers. */ |
| 77 | alphabsd_supply_fpreg (fpregs, -1); |
| 78 | } |
| 79 | |
| 80 | static void |
| 81 | fetch_elfcore_registers (char *core_reg_sect, unsigned core_reg_size, int which, |
| 82 | CORE_ADDR ignore) |
| 83 | { |
| 84 | switch (which) |
| 85 | { |
| 86 | case 0: /* Integer registers. */ |
| 87 | if (core_reg_size != SIZEOF_STRUCT_REG) |
| 88 | warning ("Wrong size register set in core file."); |
| 89 | else |
| 90 | alphabsd_supply_reg (core_reg_sect, -1); |
| 91 | break; |
| 92 | |
| 93 | case 2: /* Floating point registers. */ |
| 94 | if (core_reg_size != SIZEOF_STRUCT_FPREG) |
| 95 | warning ("Wrong size FP register set in core file."); |
| 96 | else |
| 97 | alphabsd_supply_fpreg (core_reg_sect, -1); |
| 98 | break; |
| 99 | |
| 100 | default: |
| 101 | /* Don't know what kind of register request this is; just ignore it. */ |
| 102 | break; |
| 103 | } |
| 104 | } |
| 105 | |
| 106 | static struct core_fns alphanbsd_core_fns = |
| 107 | { |
| 108 | bfd_target_unknown_flavour, /* core_flavour */ |
| 109 | default_check_format, /* check_format */ |
| 110 | default_core_sniffer, /* core_sniffer */ |
| 111 | fetch_core_registers, /* core_read_registers */ |
| 112 | NULL /* next */ |
| 113 | }; |
| 114 | |
| 115 | static struct core_fns alphanbsd_elfcore_fns = |
| 116 | { |
| 117 | bfd_target_elf_flavour, /* core_flavour */ |
| 118 | default_check_format, /* check_format */ |
| 119 | default_core_sniffer, /* core_sniffer */ |
| 120 | fetch_elfcore_registers, /* core_read_registers */ |
| 121 | NULL /* next */ |
| 122 | }; |
| 123 | |
| 124 | /* Under NetBSD/alpha, signal handler invocations can be identified by the |
| 125 | designated code sequence that is used to return from a signal handler. |
| 126 | In particular, the return address of a signal handler points to the |
| 127 | following code sequence: |
| 128 | |
| 129 | ldq a0, 0(sp) |
| 130 | lda sp, 16(sp) |
| 131 | lda v0, 295(zero) # __sigreturn14 |
| 132 | call_pal callsys |
| 133 | |
| 134 | Each instruction has a unique encoding, so we simply attempt to match |
| 135 | the instruction the PC is pointing to with any of the above instructions. |
| 136 | If there is a hit, we know the offset to the start of the designated |
| 137 | sequence and can then check whether we really are executing in the |
| 138 | signal trampoline. If not, -1 is returned, otherwise the offset from the |
| 139 | start of the return sequence is returned. */ |
| 140 | static const unsigned char sigtramp_retcode[] = |
| 141 | { |
| 142 | 0x00, 0x00, 0x1e, 0xa6, /* ldq a0, 0(sp) */ |
| 143 | 0x10, 0x00, 0xde, 0x23, /* lda sp, 16(sp) */ |
| 144 | 0x27, 0x01, 0x1f, 0x20, /* lda v0, 295(zero) */ |
| 145 | 0x83, 0x00, 0x00, 0x00, /* call_pal callsys */ |
| 146 | }; |
| 147 | #define RETCODE_NWORDS 4 |
| 148 | #define RETCODE_SIZE (RETCODE_NWORDS * 4) |
| 149 | |
| 150 | LONGEST |
| 151 | alphanbsd_sigtramp_offset (CORE_ADDR pc) |
| 152 | { |
| 153 | unsigned char ret[RETCODE_SIZE], w[4]; |
| 154 | LONGEST off; |
| 155 | int i; |
| 156 | |
| 157 | if (read_memory_nobpt (pc, (char *) w, 4) != 0) |
| 158 | return -1; |
| 159 | |
| 160 | for (i = 0; i < RETCODE_NWORDS; i++) |
| 161 | { |
| 162 | if (memcmp (w, sigtramp_retcode + (i * 4), 4) == 0) |
| 163 | break; |
| 164 | } |
| 165 | if (i == RETCODE_NWORDS) |
| 166 | return (-1); |
| 167 | |
| 168 | off = i * 4; |
| 169 | pc -= off; |
| 170 | |
| 171 | if (read_memory_nobpt (pc, (char *) ret, sizeof (ret)) != 0) |
| 172 | return -1; |
| 173 | |
| 174 | if (memcmp (ret, sigtramp_retcode, RETCODE_SIZE) == 0) |
| 175 | return off; |
| 176 | |
| 177 | return -1; |
| 178 | } |
| 179 | |
| 180 | static int |
| 181 | alphanbsd_pc_in_sigtramp (CORE_ADDR pc, char *func_name) |
| 182 | { |
| 183 | return (nbsd_pc_in_sigtramp (pc, func_name) |
| 184 | || alphanbsd_sigtramp_offset (pc) >= 0); |
| 185 | } |
| 186 | |
| 187 | static CORE_ADDR |
| 188 | alphanbsd_sigcontext_addr (struct frame_info *frame) |
| 189 | { |
| 190 | /* FIXME: This is not correct for all versions of NetBSD/alpha. |
| 191 | We will probably need to disassemble the trampoline to figure |
| 192 | out which trampoline frame type we have. */ |
| 193 | return frame->frame; |
| 194 | } |
| 195 | |
| 196 | static CORE_ADDR |
| 197 | alphanbsd_skip_sigtramp_frame (struct frame_info *frame, CORE_ADDR pc) |
| 198 | { |
| 199 | char *name; |
| 200 | |
| 201 | /* FIXME: This is not correct for all versions of NetBSD/alpha. |
| 202 | We will probably need to disassemble the trampoline to figure |
| 203 | out which trampoline frame type we have. */ |
| 204 | find_pc_partial_function (pc, &name, (CORE_ADDR *) NULL, (CORE_ADDR *) NULL); |
| 205 | if (PC_IN_SIGTRAMP (pc, name)) |
| 206 | return frame->frame; |
| 207 | return 0; |
| 208 | } |
| 209 | |
| 210 | static void |
| 211 | alphanbsd_init_abi (struct gdbarch_info info, |
| 212 | struct gdbarch *gdbarch) |
| 213 | { |
| 214 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 215 | |
| 216 | set_gdbarch_pc_in_sigtramp (gdbarch, alphanbsd_pc_in_sigtramp); |
| 217 | |
| 218 | /* NetBSD/alpha does not provide single step support via ptrace(2); we |
| 219 | must use software single-stepping. */ |
| 220 | set_gdbarch_software_single_step (gdbarch, alpha_software_single_step); |
| 221 | |
| 222 | set_solib_svr4_fetch_link_map_offsets (gdbarch, |
| 223 | nbsd_lp64_solib_svr4_fetch_link_map_offsets); |
| 224 | |
| 225 | tdep->skip_sigtramp_frame = alphanbsd_skip_sigtramp_frame; |
| 226 | tdep->dynamic_sigtramp_offset = alphanbsd_sigtramp_offset; |
| 227 | tdep->sigcontext_addr = alphanbsd_sigcontext_addr; |
| 228 | |
| 229 | tdep->jb_pc = 2; |
| 230 | tdep->jb_elt_size = 8; |
| 231 | } |
| 232 | |
| 233 | void |
| 234 | _initialize_alphanbsd_tdep (void) |
| 235 | { |
| 236 | gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_NETBSD_ELF, |
| 237 | alphanbsd_init_abi); |
| 238 | |
| 239 | add_core_fns (&alphanbsd_core_fns); |
| 240 | add_core_fns (&alphanbsd_elfcore_fns); |
| 241 | } |