1 /* Intel 386 native support for System V systems (pre-SVR4). 2 3 Copyright 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 4 1999, 2000, 2002 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 25 #ifdef HAVE_PTRACE_H 26 #include <ptrace.h> 27 #else 28 #ifdef HAVE_SYS_PTRACE_H 29 #include <sys/ptrace.h> 30 #endif 31 #endif 32 33 #include "frame.h" 34 #include "inferior.h" 35 #include "language.h" 36 #include "gdbcore.h" 37 38 #include <sys/param.h> 39 #include <sys/dir.h> 40 #include <signal.h> 41 #include <sys/user.h> 42 #include <sys/ioctl.h> 43 #include <fcntl.h> 44 45 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS 46 #include <sys/debugreg.h> 47 #endif 48 49 #include <sys/file.h> 50 #include "gdb_stat.h" 51 52 #ifdef HAVE_SYS_REG_H 53 #include <sys/reg.h> 54 #endif 55 56 #include "floatformat.h" 57 58 #include "target.h" 59 60 #include "i386-tdep.h" 61 62 63 /* Mapping between the general-purpose registers in `struct user' 64 format and GDB's register array layout. */ 65 static int regmap[] = 66 { 67 EAX, ECX, EDX, EBX, 68 UESP, EBP, ESI, EDI, 69 EIP, EFL, CS, SS, 70 DS, ES, FS, GS, 71 }; 72 73 /* Support for the user struct. */ 74 75 /* Return the address of register REGNUM. BLOCKEND is the value of 76 u.u_ar0, and points to the place where GS is stored. */ 77 78 CORE_ADDR 79 register_u_addr (CORE_ADDR blockend, int regnum) 80 { 81 struct user u; 82 CORE_ADDR fpstate; 83 84 if (i386_fp_regnum_p (regnum)) 85 { 86 #ifdef KSTKSZ /* SCO, and others? */ 87 blockend += 4 * (SS + 1) - KSTKSZ; 88 fpstate = blockend + ((char *) &u.u_fps.u_fpstate - (char *) &u); 89 return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM)); 90 #else 91 fpstate = blockend + ((char *) &u.i387.st_space - (char *) &u); 92 return (fpstate + 10 * (regnum - FP0_REGNUM)); 93 #endif 94 } 95 96 return (blockend + 4 * regmap[regnum]); 97 } 98 99 /* Return the size of the user struct. */ 100 101 int 102 kernel_u_size (void) 103 { 104 return (sizeof (struct user)); 105 } 106 107 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS 108 109 #if !defined (offsetof) 110 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER) 111 #endif 112 113 /* Record the value of the debug control register. */ 114 static int debug_control_mirror; 115 116 /* Record which address associates with which register. */ 117 static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1]; 118 119 static int i386_insert_aligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, 120 int); 121 122 static int i386_insert_nonaligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, 123 int); 124 125 /* Insert a watchpoint. */ 126 127 int 128 i386_insert_watchpoint (int pid, CORE_ADDR addr, int len, int rw) 129 { 130 return i386_insert_aligned_watchpoint (pid, addr, addr, len, rw); 131 } 132 133 static int 134 i386_insert_aligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr, 135 int len, int rw) 136 { 137 int i; 138 int read_write_bits, len_bits; 139 int free_debug_register; 140 int register_number; 141 142 /* Look for a free debug register. */ 143 for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++) 144 { 145 if (address_lookup[i - DR_FIRSTADDR] == 0) 146 break; 147 } 148 149 /* No more debug registers! */ 150 if (i > DR_LASTADDR) 151 return -1; 152 153 read_write_bits = (rw & 1) ? DR_RW_READ : DR_RW_WRITE; 154 155 if (len == 1) 156 len_bits = DR_LEN_1; 157 else if (len == 2) 158 { 159 if (addr % 2) 160 return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw); 161 len_bits = DR_LEN_2; 162 } 163 164 else if (len == 4) 165 { 166 if (addr % 4) 167 return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw); 168 len_bits = DR_LEN_4; 169 } 170 else 171 return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw); 172 173 free_debug_register = i; 174 register_number = free_debug_register - DR_FIRSTADDR; 175 debug_control_mirror |= 176 ((read_write_bits | len_bits) 177 << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number)); 178 debug_control_mirror |= 179 (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number)); 180 debug_control_mirror |= DR_LOCAL_SLOWDOWN; 181 debug_control_mirror &= ~DR_CONTROL_RESERVED; 182 183 ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]), 184 debug_control_mirror); 185 ptrace (6, pid, offsetof (struct user, u_debugreg[free_debug_register]), 186 addr); 187 188 /* Record where we came from. */ 189 address_lookup[register_number] = addr; 190 return 0; 191 } 192 193 static int 194 i386_insert_nonaligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr, 195 int len, int rw) 196 { 197 int align; 198 int size; 199 int rv; 200 201 static int size_try_array[4][4] = 202 { 203 { 1, 1, 1, 1 }, /* trying size one */ 204 { 2, 1, 2, 1 }, /* trying size two */ 205 { 2, 1, 2, 1 }, /* trying size three */ 206 { 4, 1, 2, 1 } /* trying size four */ 207 }; 208 209 rv = 0; 210 while (len > 0) 211 { 212 align = addr % 4; 213 /* Four is the maximum length for 386. */ 214 size = size_try_array[len > 4 ? 3 : len - 1][align]; 215 216 rv = i386_insert_aligned_watchpoint (pid, waddr, addr, size, rw); 217 if (rv) 218 { 219 i386_remove_watchpoint (pid, waddr, size); 220 return rv; 221 } 222 addr += size; 223 len -= size; 224 } 225 return rv; 226 } 227 228 /* Remove a watchpoint. */ 229 230 int 231 i386_remove_watchpoint (int pid, CORE_ADDR addr, int len) 232 { 233 int i; 234 int register_number; 235 236 for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++) 237 { 238 register_number = i - DR_FIRSTADDR; 239 if (address_lookup[register_number] == addr) 240 { 241 debug_control_mirror &= 242 ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number)); 243 address_lookup[register_number] = 0; 244 } 245 } 246 ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]), 247 debug_control_mirror); 248 ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0); 249 250 return 0; 251 } 252 253 /* Check if stopped by a watchpoint. */ 254 255 CORE_ADDR 256 i386_stopped_by_watchpoint (int pid) 257 { 258 int i; 259 int status; 260 261 status = ptrace (3, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0); 262 ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0); 263 264 for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++) 265 { 266 if (status & (1 << (i - DR_FIRSTADDR))) 267 return address_lookup[i - DR_FIRSTADDR]; 268 } 269 270 return 0; 271 } 272 273 #endif /* TARGET_HAS_HARDWARE_WATCHPOINTS */ 274