| 1 | /* Motorola m68k target-dependent support for GNU/Linux. |
| 2 | |
| 3 | Copyright (C) 1996, 1998, 2000, 2001, 2002, 2003, 2004, 2007, 2008, 2009, |
| 4 | 2010, 2011 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 "gdbcore.h" |
| 23 | #include "doublest.h" |
| 24 | #include "floatformat.h" |
| 25 | #include "frame.h" |
| 26 | #include "target.h" |
| 27 | #include "gdb_string.h" |
| 28 | #include "gdbtypes.h" |
| 29 | #include "osabi.h" |
| 30 | #include "regcache.h" |
| 31 | #include "objfiles.h" |
| 32 | #include "symtab.h" |
| 33 | #include "m68k-tdep.h" |
| 34 | #include "trad-frame.h" |
| 35 | #include "frame-unwind.h" |
| 36 | #include "glibc-tdep.h" |
| 37 | #include "solib-svr4.h" |
| 38 | #include "auxv.h" |
| 39 | #include "observer.h" |
| 40 | #include "elf/common.h" |
| 41 | #include "linux-tdep.h" |
| 42 | \f |
| 43 | /* Offsets (in target ints) into jmp_buf. */ |
| 44 | |
| 45 | #define M68K_LINUX_JB_ELEMENT_SIZE 4 |
| 46 | #define M68K_LINUX_JB_PC 7 |
| 47 | |
| 48 | /* Check whether insn1 and insn2 are parts of a signal trampoline. */ |
| 49 | |
| 50 | #define IS_SIGTRAMP(insn1, insn2) \ |
| 51 | (/* addaw #20,sp; moveq #119,d0; trap #0 */ \ |
| 52 | (insn1 == 0xdefc0014 && insn2 == 0x70774e40) \ |
| 53 | /* moveq #119,d0; trap #0 */ \ |
| 54 | || insn1 == 0x70774e40) |
| 55 | |
| 56 | #define IS_RT_SIGTRAMP(insn1, insn2) \ |
| 57 | (/* movel #173,d0; trap #0 */ \ |
| 58 | (insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \ |
| 59 | /* moveq #82,d0; notb d0; trap #0 */ \ |
| 60 | || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40)) |
| 61 | |
| 62 | /* Return non-zero if THIS_FRAME corresponds to a signal trampoline. For |
| 63 | the sake of m68k_linux_get_sigtramp_info we also distinguish between |
| 64 | non-RT and RT signal trampolines. */ |
| 65 | |
| 66 | static int |
| 67 | m68k_linux_pc_in_sigtramp (struct frame_info *this_frame) |
| 68 | { |
| 69 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 70 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 71 | CORE_ADDR sp; |
| 72 | gdb_byte buf[12]; |
| 73 | unsigned long insn0, insn1, insn2; |
| 74 | CORE_ADDR pc = get_frame_pc (this_frame); |
| 75 | |
| 76 | if (!safe_frame_unwind_memory (this_frame, pc - 4, buf, sizeof (buf))) |
| 77 | return 0; |
| 78 | insn1 = extract_unsigned_integer (buf + 4, 4, byte_order); |
| 79 | insn2 = extract_unsigned_integer (buf + 8, 4, byte_order); |
| 80 | if (IS_SIGTRAMP (insn1, insn2)) |
| 81 | return 1; |
| 82 | if (IS_RT_SIGTRAMP (insn1, insn2)) |
| 83 | return 2; |
| 84 | |
| 85 | insn0 = extract_unsigned_integer (buf, 4, byte_order); |
| 86 | if (IS_SIGTRAMP (insn0, insn1)) |
| 87 | return 1; |
| 88 | if (IS_RT_SIGTRAMP (insn0, insn1)) |
| 89 | return 2; |
| 90 | |
| 91 | insn0 = ((insn0 << 16) & 0xffffffff) | (insn1 >> 16); |
| 92 | insn1 = ((insn1 << 16) & 0xffffffff) | (insn2 >> 16); |
| 93 | if (IS_SIGTRAMP (insn0, insn1)) |
| 94 | return 1; |
| 95 | if (IS_RT_SIGTRAMP (insn0, insn1)) |
| 96 | return 2; |
| 97 | |
| 98 | return 0; |
| 99 | } |
| 100 | |
| 101 | /* From <asm/sigcontext.h>. */ |
| 102 | static int m68k_linux_sigcontext_reg_offset[M68K_NUM_REGS] = |
| 103 | { |
| 104 | 2 * 4, /* %d0 */ |
| 105 | 3 * 4, /* %d1 */ |
| 106 | -1, /* %d2 */ |
| 107 | -1, /* %d3 */ |
| 108 | -1, /* %d4 */ |
| 109 | -1, /* %d5 */ |
| 110 | -1, /* %d6 */ |
| 111 | -1, /* %d7 */ |
| 112 | 4 * 4, /* %a0 */ |
| 113 | 5 * 4, /* %a1 */ |
| 114 | -1, /* %a2 */ |
| 115 | -1, /* %a3 */ |
| 116 | -1, /* %a4 */ |
| 117 | -1, /* %a5 */ |
| 118 | -1, /* %fp */ |
| 119 | 1 * 4, /* %sp */ |
| 120 | 6 * 4, /* %sr */ |
| 121 | 6 * 4 + 2, /* %pc */ |
| 122 | 8 * 4, /* %fp0 */ |
| 123 | 11 * 4, /* %fp1 */ |
| 124 | -1, /* %fp2 */ |
| 125 | -1, /* %fp3 */ |
| 126 | -1, /* %fp4 */ |
| 127 | -1, /* %fp5 */ |
| 128 | -1, /* %fp6 */ |
| 129 | -1, /* %fp7 */ |
| 130 | 14 * 4, /* %fpcr */ |
| 131 | 15 * 4, /* %fpsr */ |
| 132 | 16 * 4 /* %fpiaddr */ |
| 133 | }; |
| 134 | |
| 135 | static int m68k_uclinux_sigcontext_reg_offset[M68K_NUM_REGS] = |
| 136 | { |
| 137 | 2 * 4, /* %d0 */ |
| 138 | 3 * 4, /* %d1 */ |
| 139 | -1, /* %d2 */ |
| 140 | -1, /* %d3 */ |
| 141 | -1, /* %d4 */ |
| 142 | -1, /* %d5 */ |
| 143 | -1, /* %d6 */ |
| 144 | -1, /* %d7 */ |
| 145 | 4 * 4, /* %a0 */ |
| 146 | 5 * 4, /* %a1 */ |
| 147 | -1, /* %a2 */ |
| 148 | -1, /* %a3 */ |
| 149 | -1, /* %a4 */ |
| 150 | 6 * 4, /* %a5 */ |
| 151 | -1, /* %fp */ |
| 152 | 1 * 4, /* %sp */ |
| 153 | 7 * 4, /* %sr */ |
| 154 | 7 * 4 + 2, /* %pc */ |
| 155 | -1, /* %fp0 */ |
| 156 | -1, /* %fp1 */ |
| 157 | -1, /* %fp2 */ |
| 158 | -1, /* %fp3 */ |
| 159 | -1, /* %fp4 */ |
| 160 | -1, /* %fp5 */ |
| 161 | -1, /* %fp6 */ |
| 162 | -1, /* %fp7 */ |
| 163 | -1, /* %fpcr */ |
| 164 | -1, /* %fpsr */ |
| 165 | -1 /* %fpiaddr */ |
| 166 | }; |
| 167 | |
| 168 | /* From <asm/ucontext.h>. */ |
| 169 | static int m68k_linux_ucontext_reg_offset[M68K_NUM_REGS] = |
| 170 | { |
| 171 | 6 * 4, /* %d0 */ |
| 172 | 7 * 4, /* %d1 */ |
| 173 | 8 * 4, /* %d2 */ |
| 174 | 9 * 4, /* %d3 */ |
| 175 | 10 * 4, /* %d4 */ |
| 176 | 11 * 4, /* %d5 */ |
| 177 | 12 * 4, /* %d6 */ |
| 178 | 13 * 4, /* %d7 */ |
| 179 | 14 * 4, /* %a0 */ |
| 180 | 15 * 4, /* %a1 */ |
| 181 | 16 * 4, /* %a2 */ |
| 182 | 17 * 4, /* %a3 */ |
| 183 | 18 * 4, /* %a4 */ |
| 184 | 19 * 4, /* %a5 */ |
| 185 | 20 * 4, /* %fp */ |
| 186 | 21 * 4, /* %sp */ |
| 187 | 23 * 4, /* %sr */ |
| 188 | 22 * 4, /* %pc */ |
| 189 | 27 * 4, /* %fp0 */ |
| 190 | 30 * 4, /* %fp1 */ |
| 191 | 33 * 4, /* %fp2 */ |
| 192 | 36 * 4, /* %fp3 */ |
| 193 | 39 * 4, /* %fp4 */ |
| 194 | 42 * 4, /* %fp5 */ |
| 195 | 45 * 4, /* %fp6 */ |
| 196 | 48 * 4, /* %fp7 */ |
| 197 | 24 * 4, /* %fpcr */ |
| 198 | 25 * 4, /* %fpsr */ |
| 199 | 26 * 4 /* %fpiaddr */ |
| 200 | }; |
| 201 | |
| 202 | |
| 203 | /* Get info about saved registers in sigtramp. */ |
| 204 | |
| 205 | struct m68k_linux_sigtramp_info |
| 206 | { |
| 207 | /* Address of sigcontext. */ |
| 208 | CORE_ADDR sigcontext_addr; |
| 209 | |
| 210 | /* Offset of registers in `struct sigcontext'. */ |
| 211 | int *sc_reg_offset; |
| 212 | }; |
| 213 | |
| 214 | /* Nonzero if running on uClinux. */ |
| 215 | static int target_is_uclinux; |
| 216 | |
| 217 | static void |
| 218 | m68k_linux_inferior_created (struct target_ops *objfile, int from_tty) |
| 219 | { |
| 220 | /* Record that we will need to re-evaluate whether we are running on a |
| 221 | uClinux or normal GNU/Linux target (see m68k_linux_get_sigtramp_info). */ |
| 222 | target_is_uclinux = -1; |
| 223 | } |
| 224 | |
| 225 | static struct m68k_linux_sigtramp_info |
| 226 | m68k_linux_get_sigtramp_info (struct frame_info *this_frame) |
| 227 | { |
| 228 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 229 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 230 | CORE_ADDR sp; |
| 231 | struct m68k_linux_sigtramp_info info; |
| 232 | |
| 233 | if (target_is_uclinux == -1) |
| 234 | { |
| 235 | /* Determine whether we are running on a uClinux or normal GNU/Linux |
| 236 | target so we can use the correct sigcontext layouts. */ |
| 237 | CORE_ADDR dummy; |
| 238 | |
| 239 | target_is_uclinux |
| 240 | = (target_auxv_search (¤t_target, AT_NULL, &dummy) > 0 |
| 241 | && target_auxv_search (¤t_target, AT_PAGESZ, &dummy) == 0); |
| 242 | } |
| 243 | |
| 244 | sp = get_frame_register_unsigned (this_frame, M68K_SP_REGNUM); |
| 245 | |
| 246 | /* Get sigcontext address, it is the third parameter on the stack. */ |
| 247 | info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4, byte_order); |
| 248 | |
| 249 | if (m68k_linux_pc_in_sigtramp (this_frame) == 2) |
| 250 | info.sc_reg_offset = m68k_linux_ucontext_reg_offset; |
| 251 | else |
| 252 | info.sc_reg_offset = (target_is_uclinux |
| 253 | ? m68k_uclinux_sigcontext_reg_offset |
| 254 | : m68k_linux_sigcontext_reg_offset); |
| 255 | return info; |
| 256 | } |
| 257 | |
| 258 | /* Signal trampolines. */ |
| 259 | |
| 260 | static struct trad_frame_cache * |
| 261 | m68k_linux_sigtramp_frame_cache (struct frame_info *this_frame, |
| 262 | void **this_cache) |
| 263 | { |
| 264 | struct frame_id this_id; |
| 265 | struct trad_frame_cache *cache; |
| 266 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 267 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 268 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 269 | struct m68k_linux_sigtramp_info info; |
| 270 | gdb_byte buf[4]; |
| 271 | int i; |
| 272 | |
| 273 | if (*this_cache) |
| 274 | return *this_cache; |
| 275 | |
| 276 | cache = trad_frame_cache_zalloc (this_frame); |
| 277 | |
| 278 | /* FIXME: cagney/2004-05-01: This is is long standing broken code. |
| 279 | The frame ID's code address should be the start-address of the |
| 280 | signal trampoline and not the current PC within that |
| 281 | trampoline. */ |
| 282 | get_frame_register (this_frame, M68K_SP_REGNUM, buf); |
| 283 | /* See the end of m68k_push_dummy_call. */ |
| 284 | this_id = frame_id_build (extract_unsigned_integer (buf, 4, byte_order) |
| 285 | - 4 + 8, get_frame_pc (this_frame)); |
| 286 | trad_frame_set_id (cache, this_id); |
| 287 | |
| 288 | info = m68k_linux_get_sigtramp_info (this_frame); |
| 289 | |
| 290 | for (i = 0; i < M68K_NUM_REGS; i++) |
| 291 | if (info.sc_reg_offset[i] != -1) |
| 292 | trad_frame_set_reg_addr (cache, i, |
| 293 | info.sigcontext_addr + info.sc_reg_offset[i]); |
| 294 | |
| 295 | *this_cache = cache; |
| 296 | return cache; |
| 297 | } |
| 298 | |
| 299 | static void |
| 300 | m68k_linux_sigtramp_frame_this_id (struct frame_info *this_frame, |
| 301 | void **this_cache, |
| 302 | struct frame_id *this_id) |
| 303 | { |
| 304 | struct trad_frame_cache *cache = |
| 305 | m68k_linux_sigtramp_frame_cache (this_frame, this_cache); |
| 306 | trad_frame_get_id (cache, this_id); |
| 307 | } |
| 308 | |
| 309 | static struct value * |
| 310 | m68k_linux_sigtramp_frame_prev_register (struct frame_info *this_frame, |
| 311 | void **this_cache, |
| 312 | int regnum) |
| 313 | { |
| 314 | /* Make sure we've initialized the cache. */ |
| 315 | struct trad_frame_cache *cache = |
| 316 | m68k_linux_sigtramp_frame_cache (this_frame, this_cache); |
| 317 | return trad_frame_get_register (cache, this_frame, regnum); |
| 318 | } |
| 319 | |
| 320 | static int |
| 321 | m68k_linux_sigtramp_frame_sniffer (const struct frame_unwind *self, |
| 322 | struct frame_info *this_frame, |
| 323 | void **this_prologue_cache) |
| 324 | { |
| 325 | return m68k_linux_pc_in_sigtramp (this_frame); |
| 326 | } |
| 327 | |
| 328 | static const struct frame_unwind m68k_linux_sigtramp_frame_unwind = |
| 329 | { |
| 330 | SIGTRAMP_FRAME, |
| 331 | m68k_linux_sigtramp_frame_this_id, |
| 332 | m68k_linux_sigtramp_frame_prev_register, |
| 333 | NULL, |
| 334 | m68k_linux_sigtramp_frame_sniffer |
| 335 | }; |
| 336 | |
| 337 | static void |
| 338 | m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 339 | { |
| 340 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 341 | |
| 342 | linux_init_abi (info, gdbarch); |
| 343 | |
| 344 | tdep->jb_pc = M68K_LINUX_JB_PC; |
| 345 | tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE; |
| 346 | |
| 347 | /* GNU/Linux uses a calling convention that's similar to SVR4. It |
| 348 | returns integer values in %d0/%d1, pointer values in %a0 and |
| 349 | floating values in %fp0, just like SVR4, but uses %a1 to pass the |
| 350 | address to store a structure value. It also returns small |
| 351 | structures in registers instead of memory. */ |
| 352 | m68k_svr4_init_abi (info, gdbarch); |
| 353 | tdep->struct_value_regnum = M68K_A1_REGNUM; |
| 354 | tdep->struct_return = reg_struct_return; |
| 355 | |
| 356 | set_gdbarch_decr_pc_after_break (gdbarch, 2); |
| 357 | |
| 358 | frame_unwind_append_unwinder (gdbarch, &m68k_linux_sigtramp_frame_unwind); |
| 359 | |
| 360 | /* Shared library handling. */ |
| 361 | |
| 362 | /* GNU/Linux uses SVR4-style shared libraries. */ |
| 363 | set_solib_svr4_fetch_link_map_offsets (gdbarch, |
| 364 | svr4_ilp32_fetch_link_map_offsets); |
| 365 | |
| 366 | /* GNU/Linux uses the dynamic linker included in the GNU C Library. */ |
| 367 | set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); |
| 368 | |
| 369 | set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); |
| 370 | |
| 371 | /* Enable TLS support. */ |
| 372 | set_gdbarch_fetch_tls_load_module_address (gdbarch, |
| 373 | svr4_fetch_objfile_link_map); |
| 374 | } |
| 375 | |
| 376 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 377 | extern initialize_file_ftype _initialize_m68k_linux_tdep; |
| 378 | |
| 379 | void |
| 380 | _initialize_m68k_linux_tdep (void) |
| 381 | { |
| 382 | gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX, |
| 383 | m68k_linux_init_abi); |
| 384 | observer_attach_inferior_created (m68k_linux_inferior_created); |
| 385 | } |