| 1 | /* Target-dependent code for NetBSD/alpha. |
| 2 | |
| 3 | Copyright (C) 2002-2013 Free Software Foundation, Inc. |
| 4 | |
| 5 | Contributed by Wasabi Systems, Inc. |
| 6 | |
| 7 | This file is part of GDB. |
| 8 | |
| 9 | This program is free software; you can redistribute it and/or modify |
| 10 | it under the terms of the GNU General Public License as published by |
| 11 | the Free Software Foundation; either version 3 of the License, or |
| 12 | (at your option) any later version. |
| 13 | |
| 14 | This program is distributed in the hope that it will be useful, |
| 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | GNU General Public License for more details. |
| 18 | |
| 19 | You should have received a copy of the GNU General Public License |
| 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 21 | |
| 22 | #include "defs.h" |
| 23 | #include "frame.h" |
| 24 | #include "gdbcore.h" |
| 25 | #include "osabi.h" |
| 26 | #include "regcache.h" |
| 27 | #include "regset.h" |
| 28 | #include "value.h" |
| 29 | |
| 30 | #include "gdb_assert.h" |
| 31 | #include "gdb_string.h" |
| 32 | |
| 33 | #include "alpha-tdep.h" |
| 34 | #include "alphabsd-tdep.h" |
| 35 | #include "nbsd-tdep.h" |
| 36 | #include "solib-svr4.h" |
| 37 | #include "target.h" |
| 38 | |
| 39 | /* Core file support. */ |
| 40 | |
| 41 | /* Even though NetBSD/alpha used ELF since day one, it used the |
| 42 | traditional a.out-style core dump format before NetBSD 1.6. */ |
| 43 | |
| 44 | /* Sizeof `struct reg' in <machine/reg.h>. */ |
| 45 | #define ALPHANBSD_SIZEOF_GREGS (32 * 8) |
| 46 | |
| 47 | /* Sizeof `struct fpreg' in <machine/reg.h. */ |
| 48 | #define ALPHANBSD_SIZEOF_FPREGS ((32 * 8) + 8) |
| 49 | |
| 50 | /* Supply register REGNUM from the buffer specified by FPREGS and LEN |
| 51 | in the floating-point register set REGSET to register cache |
| 52 | REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ |
| 53 | |
| 54 | static void |
| 55 | alphanbsd_supply_fpregset (const struct regset *regset, |
| 56 | struct regcache *regcache, |
| 57 | int regnum, const void *fpregs, size_t len) |
| 58 | { |
| 59 | const gdb_byte *regs = fpregs; |
| 60 | int i; |
| 61 | |
| 62 | gdb_assert (len >= ALPHANBSD_SIZEOF_FPREGS); |
| 63 | |
| 64 | for (i = ALPHA_FP0_REGNUM; i < ALPHA_FP0_REGNUM + 31; i++) |
| 65 | { |
| 66 | if (regnum == i || regnum == -1) |
| 67 | regcache_raw_supply (regcache, i, regs + (i - ALPHA_FP0_REGNUM) * 8); |
| 68 | } |
| 69 | |
| 70 | if (regnum == ALPHA_FPCR_REGNUM || regnum == -1) |
| 71 | regcache_raw_supply (regcache, ALPHA_FPCR_REGNUM, regs + 32 * 8); |
| 72 | } |
| 73 | |
| 74 | /* Supply register REGNUM from the buffer specified by GREGS and LEN |
| 75 | in the general-purpose register set REGSET to register cache |
| 76 | REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ |
| 77 | |
| 78 | static void |
| 79 | alphanbsd_supply_gregset (const struct regset *regset, |
| 80 | struct regcache *regcache, |
| 81 | int regnum, const void *gregs, size_t len) |
| 82 | { |
| 83 | const gdb_byte *regs = gregs; |
| 84 | int i; |
| 85 | |
| 86 | gdb_assert (len >= ALPHANBSD_SIZEOF_GREGS); |
| 87 | |
| 88 | for (i = 0; i < ALPHA_ZERO_REGNUM; i++) |
| 89 | { |
| 90 | if (regnum == i || regnum == -1) |
| 91 | regcache_raw_supply (regcache, i, regs + i * 8); |
| 92 | } |
| 93 | |
| 94 | if (regnum == ALPHA_PC_REGNUM || regnum == -1) |
| 95 | regcache_raw_supply (regcache, ALPHA_PC_REGNUM, regs + 31 * 8); |
| 96 | } |
| 97 | |
| 98 | /* Supply register REGNUM from the buffer specified by GREGS and LEN |
| 99 | in the general-purpose register set REGSET to register cache |
| 100 | REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ |
| 101 | |
| 102 | static void |
| 103 | alphanbsd_aout_supply_gregset (const struct regset *regset, |
| 104 | struct regcache *regcache, |
| 105 | int regnum, const void *gregs, size_t len) |
| 106 | { |
| 107 | const gdb_byte *regs = gregs; |
| 108 | int i; |
| 109 | |
| 110 | /* Table to map a GDB register number to a trapframe register index. */ |
| 111 | static const int regmap[] = |
| 112 | { |
| 113 | 0, 1, 2, 3, |
| 114 | 4, 5, 6, 7, |
| 115 | 8, 9, 10, 11, |
| 116 | 12, 13, 14, 15, |
| 117 | 30, 31, 32, 16, |
| 118 | 17, 18, 19, 20, |
| 119 | 21, 22, 23, 24, |
| 120 | 25, 29, 26 |
| 121 | }; |
| 122 | |
| 123 | gdb_assert (len >= ALPHANBSD_SIZEOF_GREGS); |
| 124 | |
| 125 | for (i = 0; i < ARRAY_SIZE(regmap); i++) |
| 126 | { |
| 127 | if (regnum == i || regnum == -1) |
| 128 | regcache_raw_supply (regcache, i, regs + regmap[i] * 8); |
| 129 | } |
| 130 | |
| 131 | if (regnum == ALPHA_PC_REGNUM || regnum == -1) |
| 132 | regcache_raw_supply (regcache, ALPHA_PC_REGNUM, regs + 31 * 8); |
| 133 | |
| 134 | if (len >= ALPHANBSD_SIZEOF_GREGS + ALPHANBSD_SIZEOF_FPREGS) |
| 135 | { |
| 136 | regs += ALPHANBSD_SIZEOF_GREGS; |
| 137 | len -= ALPHANBSD_SIZEOF_GREGS; |
| 138 | alphanbsd_supply_fpregset (regset, regcache, regnum, regs, len); |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | /* NetBSD/alpha register sets. */ |
| 143 | |
| 144 | static struct regset alphanbsd_gregset = |
| 145 | { |
| 146 | NULL, |
| 147 | alphanbsd_supply_gregset |
| 148 | }; |
| 149 | |
| 150 | static struct regset alphanbsd_fpregset = |
| 151 | { |
| 152 | NULL, |
| 153 | alphanbsd_supply_fpregset |
| 154 | }; |
| 155 | |
| 156 | static struct regset alphanbsd_aout_gregset = |
| 157 | { |
| 158 | NULL, |
| 159 | alphanbsd_aout_supply_gregset |
| 160 | }; |
| 161 | |
| 162 | /* Return the appropriate register set for the core section identified |
| 163 | by SECT_NAME and SECT_SIZE. */ |
| 164 | |
| 165 | const struct regset * |
| 166 | alphanbsd_regset_from_core_section (struct gdbarch *gdbarch, |
| 167 | const char *sect_name, size_t sect_size) |
| 168 | { |
| 169 | if (strcmp (sect_name, ".reg") == 0 && sect_size >= ALPHANBSD_SIZEOF_GREGS) |
| 170 | { |
| 171 | if (sect_size >= ALPHANBSD_SIZEOF_GREGS + ALPHANBSD_SIZEOF_FPREGS) |
| 172 | return &alphanbsd_aout_gregset; |
| 173 | else |
| 174 | return &alphanbsd_gregset; |
| 175 | } |
| 176 | |
| 177 | if (strcmp (sect_name, ".reg2") == 0 && sect_size >= ALPHANBSD_SIZEOF_FPREGS) |
| 178 | return &alphanbsd_fpregset; |
| 179 | |
| 180 | return NULL; |
| 181 | } |
| 182 | \f |
| 183 | |
| 184 | /* Signal trampolines. */ |
| 185 | |
| 186 | /* Under NetBSD/alpha, signal handler invocations can be identified by the |
| 187 | designated code sequence that is used to return from a signal handler. |
| 188 | In particular, the return address of a signal handler points to the |
| 189 | following code sequence: |
| 190 | |
| 191 | ldq a0, 0(sp) |
| 192 | lda sp, 16(sp) |
| 193 | lda v0, 295(zero) # __sigreturn14 |
| 194 | call_pal callsys |
| 195 | |
| 196 | Each instruction has a unique encoding, so we simply attempt to match |
| 197 | the instruction the PC is pointing to with any of the above instructions. |
| 198 | If there is a hit, we know the offset to the start of the designated |
| 199 | sequence and can then check whether we really are executing in the |
| 200 | signal trampoline. If not, -1 is returned, otherwise the offset from the |
| 201 | start of the return sequence is returned. */ |
| 202 | static const unsigned char sigtramp_retcode[] = |
| 203 | { |
| 204 | 0x00, 0x00, 0x1e, 0xa6, /* ldq a0, 0(sp) */ |
| 205 | 0x10, 0x00, 0xde, 0x23, /* lda sp, 16(sp) */ |
| 206 | 0x27, 0x01, 0x1f, 0x20, /* lda v0, 295(zero) */ |
| 207 | 0x83, 0x00, 0x00, 0x00, /* call_pal callsys */ |
| 208 | }; |
| 209 | #define RETCODE_NWORDS 4 |
| 210 | #define RETCODE_SIZE (RETCODE_NWORDS * 4) |
| 211 | |
| 212 | static LONGEST |
| 213 | alphanbsd_sigtramp_offset (struct gdbarch *gdbarch, CORE_ADDR pc) |
| 214 | { |
| 215 | unsigned char ret[RETCODE_SIZE], w[4]; |
| 216 | LONGEST off; |
| 217 | int i; |
| 218 | |
| 219 | if (target_read_memory (pc, (char *) w, 4) != 0) |
| 220 | return -1; |
| 221 | |
| 222 | for (i = 0; i < RETCODE_NWORDS; i++) |
| 223 | { |
| 224 | if (memcmp (w, sigtramp_retcode + (i * 4), 4) == 0) |
| 225 | break; |
| 226 | } |
| 227 | if (i == RETCODE_NWORDS) |
| 228 | return (-1); |
| 229 | |
| 230 | off = i * 4; |
| 231 | pc -= off; |
| 232 | |
| 233 | if (target_read_memory (pc, (char *) ret, sizeof (ret)) != 0) |
| 234 | return -1; |
| 235 | |
| 236 | if (memcmp (ret, sigtramp_retcode, RETCODE_SIZE) == 0) |
| 237 | return off; |
| 238 | |
| 239 | return -1; |
| 240 | } |
| 241 | |
| 242 | static int |
| 243 | alphanbsd_pc_in_sigtramp (struct gdbarch *gdbarch, |
| 244 | CORE_ADDR pc, const char *func_name) |
| 245 | { |
| 246 | return (nbsd_pc_in_sigtramp (pc, func_name) |
| 247 | || alphanbsd_sigtramp_offset (gdbarch, pc) >= 0); |
| 248 | } |
| 249 | |
| 250 | static CORE_ADDR |
| 251 | alphanbsd_sigcontext_addr (struct frame_info *frame) |
| 252 | { |
| 253 | /* FIXME: This is not correct for all versions of NetBSD/alpha. |
| 254 | We will probably need to disassemble the trampoline to figure |
| 255 | out which trampoline frame type we have. */ |
| 256 | if (!get_next_frame (frame)) |
| 257 | return 0; |
| 258 | return get_frame_base (get_next_frame (frame)); |
| 259 | } |
| 260 | \f |
| 261 | |
| 262 | static void |
| 263 | alphanbsd_init_abi (struct gdbarch_info info, |
| 264 | struct gdbarch *gdbarch) |
| 265 | { |
| 266 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 267 | |
| 268 | /* Hook into the DWARF CFI frame unwinder. */ |
| 269 | alpha_dwarf2_init_abi (info, gdbarch); |
| 270 | |
| 271 | /* Hook into the MDEBUG frame unwinder. */ |
| 272 | alpha_mdebug_init_abi (info, gdbarch); |
| 273 | |
| 274 | /* NetBSD/alpha does not provide single step support via ptrace(2); we |
| 275 | must use software single-stepping. */ |
| 276 | set_gdbarch_software_single_step (gdbarch, alpha_software_single_step); |
| 277 | |
| 278 | /* NetBSD/alpha has SVR4-style shared libraries. */ |
| 279 | set_solib_svr4_fetch_link_map_offsets |
| 280 | (gdbarch, svr4_lp64_fetch_link_map_offsets); |
| 281 | |
| 282 | tdep->dynamic_sigtramp_offset = alphanbsd_sigtramp_offset; |
| 283 | tdep->pc_in_sigtramp = alphanbsd_pc_in_sigtramp; |
| 284 | tdep->sigcontext_addr = alphanbsd_sigcontext_addr; |
| 285 | |
| 286 | tdep->jb_pc = 2; |
| 287 | tdep->jb_elt_size = 8; |
| 288 | |
| 289 | set_gdbarch_regset_from_core_section |
| 290 | (gdbarch, alphanbsd_regset_from_core_section); |
| 291 | } |
| 292 | \f |
| 293 | |
| 294 | static enum gdb_osabi |
| 295 | alphanbsd_core_osabi_sniffer (bfd *abfd) |
| 296 | { |
| 297 | if (strcmp (bfd_get_target (abfd), "netbsd-core") == 0) |
| 298 | return GDB_OSABI_NETBSD_ELF; |
| 299 | |
| 300 | return GDB_OSABI_UNKNOWN; |
| 301 | } |
| 302 | \f |
| 303 | |
| 304 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 305 | void _initialize_alphanbsd_tdep (void); |
| 306 | |
| 307 | void |
| 308 | _initialize_alphanbsd_tdep (void) |
| 309 | { |
| 310 | /* BFD doesn't set a flavour for NetBSD style a.out core files. */ |
| 311 | gdbarch_register_osabi_sniffer (bfd_arch_alpha, bfd_target_unknown_flavour, |
| 312 | alphanbsd_core_osabi_sniffer); |
| 313 | |
| 314 | gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_NETBSD_ELF, |
| 315 | alphanbsd_init_abi); |
| 316 | } |