1 /* Motorola m68k target-dependent support for GNU/Linux. 2 3 Copyright 1996, 1998, 2000, 2001, 2002, 2003, 2004 4 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 2 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, write to the Free Software 20 Foundation, Inc., 59 Temple Place - Suite 330, 21 Boston, MA 02111-1307, USA. */ 22 23 #include "defs.h" 24 #include "gdbcore.h" 25 #include "doublest.h" 26 #include "floatformat.h" 27 #include "frame.h" 28 #include "target.h" 29 #include "gdb_string.h" 30 #include "gdbtypes.h" 31 #include "osabi.h" 32 #include "regcache.h" 33 #include "objfiles.h" 34 #include "symtab.h" 35 #include "m68k-tdep.h" 36 #include "trad-frame.h" 37 #include "frame-unwind.h" 38 39 /* Offsets (in target ints) into jmp_buf. */ 40 41 #define M68K_LINUX_JB_ELEMENT_SIZE 4 42 #define M68K_LINUX_JB_PC 7 43 44 /* Check whether insn1 and insn2 are parts of a signal trampoline. */ 45 46 #define IS_SIGTRAMP(insn1, insn2) \ 47 (/* addaw #20,sp; moveq #119,d0; trap #0 */ \ 48 (insn1 == 0xdefc0014 && insn2 == 0x70774e40) \ 49 /* moveq #119,d0; trap #0 */ \ 50 || insn1 == 0x70774e40) 51 52 #define IS_RT_SIGTRAMP(insn1, insn2) \ 53 (/* movel #173,d0; trap #0 */ \ 54 (insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \ 55 /* moveq #82,d0; notb d0; trap #0 */ \ 56 || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40)) 57 58 /* Return non-zero if PC points into the signal trampoline. For the 59 sake of m68k_linux_get_sigtramp_info we also distinguish between 60 non-RT and RT signal trampolines. */ 61 62 static int 63 m68k_linux_pc_in_sigtramp (CORE_ADDR pc, char *name) 64 { 65 CORE_ADDR sp; 66 char buf[12]; 67 unsigned long insn0, insn1, insn2; 68 69 if (deprecated_read_memory_nobpt (pc - 4, buf, sizeof (buf))) 70 return 0; 71 insn1 = extract_unsigned_integer (buf + 4, 4); 72 insn2 = extract_unsigned_integer (buf + 8, 4); 73 if (IS_SIGTRAMP (insn1, insn2)) 74 return 1; 75 if (IS_RT_SIGTRAMP (insn1, insn2)) 76 return 2; 77 78 insn0 = extract_unsigned_integer (buf, 4); 79 if (IS_SIGTRAMP (insn0, insn1)) 80 return 1; 81 if (IS_RT_SIGTRAMP (insn0, insn1)) 82 return 2; 83 84 insn0 = ((insn0 << 16) & 0xffffffff) | (insn1 >> 16); 85 insn1 = ((insn1 << 16) & 0xffffffff) | (insn2 >> 16); 86 if (IS_SIGTRAMP (insn0, insn1)) 87 return 1; 88 if (IS_RT_SIGTRAMP (insn0, insn1)) 89 return 2; 90 91 return 0; 92 } 93 94 /* From <asm/sigcontext.h>. */ 95 static int m68k_linux_sigcontext_reg_offset[M68K_NUM_REGS] = 96 { 97 2 * 4, /* %d0 */ 98 3 * 4, /* %d1 */ 99 -1, /* %d2 */ 100 -1, /* %d3 */ 101 -1, /* %d4 */ 102 -1, /* %d5 */ 103 -1, /* %d6 */ 104 -1, /* %d7 */ 105 4 * 4, /* %a0 */ 106 5 * 4, /* %a1 */ 107 -1, /* %a2 */ 108 -1, /* %a3 */ 109 -1, /* %a4 */ 110 -1, /* %a5 */ 111 -1, /* %fp */ 112 1 * 4, /* %sp */ 113 5 * 4 + 2, /* %sr */ 114 6 * 4 + 2, /* %pc */ 115 8 * 4, /* %fp0 */ 116 11 * 4, /* %fp1 */ 117 -1, /* %fp2 */ 118 -1, /* %fp3 */ 119 -1, /* %fp4 */ 120 -1, /* %fp5 */ 121 -1, /* %fp6 */ 122 -1, /* %fp7 */ 123 14 * 4, /* %fpcr */ 124 15 * 4, /* %fpsr */ 125 16 * 4 /* %fpiaddr */ 126 }; 127 128 /* From <asm/ucontext.h>. */ 129 static int m68k_linux_ucontext_reg_offset[M68K_NUM_REGS] = 130 { 131 6 * 4, /* %d0 */ 132 7 * 4, /* %d1 */ 133 8 * 4, /* %d2 */ 134 9 * 4, /* %d3 */ 135 10 * 4, /* %d4 */ 136 11 * 4, /* %d5 */ 137 12 * 4, /* %d6 */ 138 13 * 4, /* %d7 */ 139 14 * 4, /* %a0 */ 140 15 * 4, /* %a1 */ 141 16 * 4, /* %a2 */ 142 17 * 4, /* %a3 */ 143 18 * 4, /* %a4 */ 144 19 * 4, /* %a5 */ 145 20 * 4, /* %fp */ 146 21 * 4, /* %sp */ 147 23 * 4, /* %sr */ 148 22 * 4, /* %pc */ 149 27 * 4, /* %fp0 */ 150 30 * 4, /* %fp1 */ 151 33 * 4, /* %fp2 */ 152 36 * 4, /* %fp3 */ 153 39 * 4, /* %fp4 */ 154 42 * 4, /* %fp5 */ 155 45 * 4, /* %fp6 */ 156 48 * 4, /* %fp7 */ 157 24 * 4, /* %fpcr */ 158 25 * 4, /* %fpsr */ 159 26 * 4 /* %fpiaddr */ 160 }; 161 162 163 /* Get info about saved registers in sigtramp. */ 164 165 struct m68k_linux_sigtramp_info 166 { 167 /* Address of sigcontext. */ 168 CORE_ADDR sigcontext_addr; 169 170 /* Offset of registers in `struct sigcontext'. */ 171 int *sc_reg_offset; 172 }; 173 174 static struct m68k_linux_sigtramp_info 175 m68k_linux_get_sigtramp_info (struct frame_info *next_frame) 176 { 177 CORE_ADDR sp; 178 char buf[4]; 179 struct m68k_linux_sigtramp_info info; 180 181 frame_unwind_register (next_frame, M68K_SP_REGNUM, buf); 182 sp = extract_unsigned_integer (buf, 4); 183 184 /* Get sigcontext address, it is the third parameter on the stack. */ 185 info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4); 186 187 if (m68k_linux_pc_in_sigtramp (frame_pc_unwind (next_frame), 0) == 2) 188 info.sc_reg_offset = m68k_linux_ucontext_reg_offset; 189 else 190 info.sc_reg_offset = m68k_linux_sigcontext_reg_offset; 191 return info; 192 } 193 194 /* Signal trampolines. */ 195 196 static struct trad_frame_cache * 197 m68k_linux_sigtramp_frame_cache (struct frame_info *next_frame, 198 void **this_cache) 199 { 200 struct frame_id this_id; 201 struct trad_frame_cache *cache; 202 struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch); 203 struct m68k_linux_sigtramp_info info; 204 char buf[4]; 205 int i; 206 207 if (*this_cache) 208 return *this_cache; 209 210 cache = trad_frame_cache_zalloc (next_frame); 211 212 /* FIXME: cagney/2004-05-01: This is is long standing broken code. 213 The frame ID's code address should be the start-address of the 214 signal trampoline and not the current PC within that 215 trampoline. */ 216 frame_unwind_register (next_frame, M68K_SP_REGNUM, buf); 217 /* See the end of m68k_push_dummy_call. */ 218 this_id = frame_id_build (extract_unsigned_integer (buf, 4) - 4 + 8, 219 frame_pc_unwind (next_frame)); 220 trad_frame_set_id (cache, this_id); 221 222 info = m68k_linux_get_sigtramp_info (next_frame); 223 224 for (i = 0; i < M68K_NUM_REGS; i++) 225 if (info.sc_reg_offset[i] != -1) 226 trad_frame_set_reg_addr (cache, i, 227 info.sigcontext_addr + info.sc_reg_offset[i]); 228 229 *this_cache = cache; 230 return cache; 231 } 232 233 static void 234 m68k_linux_sigtramp_frame_this_id (struct frame_info *next_frame, 235 void **this_cache, 236 struct frame_id *this_id) 237 { 238 struct trad_frame_cache *cache = 239 m68k_linux_sigtramp_frame_cache (next_frame, this_cache); 240 trad_frame_get_id (cache, this_id); 241 } 242 243 static void 244 m68k_linux_sigtramp_frame_prev_register (struct frame_info *next_frame, 245 void **this_cache, 246 int regnum, int *optimizedp, 247 enum lval_type *lvalp, 248 CORE_ADDR *addrp, 249 int *realnump, void *valuep) 250 { 251 /* Make sure we've initialized the cache. */ 252 struct trad_frame_cache *cache = 253 m68k_linux_sigtramp_frame_cache (next_frame, this_cache); 254 trad_frame_get_register (cache, next_frame, regnum, optimizedp, lvalp, 255 addrp, realnump, valuep); 256 } 257 258 static const struct frame_unwind m68k_linux_sigtramp_frame_unwind = 259 { 260 SIGTRAMP_FRAME, 261 m68k_linux_sigtramp_frame_this_id, 262 m68k_linux_sigtramp_frame_prev_register 263 }; 264 265 static const struct frame_unwind * 266 m68k_linux_sigtramp_frame_sniffer (struct frame_info *next_frame) 267 { 268 CORE_ADDR pc = frame_pc_unwind (next_frame); 269 char *name; 270 271 find_pc_partial_function (pc, &name, NULL, NULL); 272 if (m68k_linux_pc_in_sigtramp (pc, name)) 273 return &m68k_linux_sigtramp_frame_unwind; 274 275 return NULL; 276 } 277 278 static void 279 m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 280 { 281 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 282 283 tdep->jb_pc = M68K_LINUX_JB_PC; 284 tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE; 285 286 /* GNU/Linux uses a calling convention that's similar to SVR4. It 287 returns integer values in %d0/%di, pointer values in %a0 and 288 floating values in %fp0, just like SVR4, but uses %a1 to pass the 289 address to store a structure value. It also returns small 290 structures in registers instead of memory. */ 291 m68k_svr4_init_abi (info, gdbarch); 292 tdep->struct_value_regnum = M68K_A1_REGNUM; 293 tdep->struct_return = reg_struct_return; 294 295 frame_unwind_append_sniffer (gdbarch, m68k_linux_sigtramp_frame_sniffer); 296 297 /* Shared library handling. */ 298 set_gdbarch_in_solib_call_trampoline (gdbarch, in_plt_section); 299 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); 300 } 301 302 void 303 _initialize_m68k_linux_tdep (void) 304 { 305 gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX, 306 m68k_linux_init_abi); 307 } 308