1 /* 2 * i386 breakpoint helpers - sysemu code 3 * 4 * Copyright (c) 2003 Fabrice Bellard 5 * 6 * This library is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * This library is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with this library; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include "qemu/osdep.h" 21 #include "cpu.h" 22 #include "exec/exec-all.h" 23 #include "exec/helper-proto.h" 24 #include "tcg/helper-tcg.h" 25 26 27 static inline bool hw_local_breakpoint_enabled(unsigned long dr7, int index) 28 { 29 return (dr7 >> (index * 2)) & 1; 30 } 31 32 static inline bool hw_global_breakpoint_enabled(unsigned long dr7, int index) 33 { 34 return (dr7 >> (index * 2)) & 2; 35 36 } 37 static inline bool hw_breakpoint_enabled(unsigned long dr7, int index) 38 { 39 return hw_global_breakpoint_enabled(dr7, index) || 40 hw_local_breakpoint_enabled(dr7, index); 41 } 42 43 static inline int hw_breakpoint_type(unsigned long dr7, int index) 44 { 45 return (dr7 >> (DR7_TYPE_SHIFT + (index * 4))) & 3; 46 } 47 48 static inline int hw_breakpoint_len(unsigned long dr7, int index) 49 { 50 int len = ((dr7 >> (DR7_LEN_SHIFT + (index * 4))) & 3); 51 return (len == 2) ? 8 : len + 1; 52 } 53 54 static int hw_breakpoint_insert(CPUX86State *env, int index) 55 { 56 CPUState *cs = env_cpu(env); 57 target_ulong dr7 = env->dr[7]; 58 target_ulong drN = env->dr[index]; 59 int err = 0; 60 61 switch (hw_breakpoint_type(dr7, index)) { 62 case DR7_TYPE_BP_INST: 63 if (hw_breakpoint_enabled(dr7, index)) { 64 err = cpu_breakpoint_insert(cs, drN, BP_CPU, 65 &env->cpu_breakpoint[index]); 66 } 67 break; 68 69 case DR7_TYPE_IO_RW: 70 /* Notice when we should enable calls to bpt_io. */ 71 return hw_breakpoint_enabled(env->dr[7], index) 72 ? HF_IOBPT_MASK : 0; 73 74 case DR7_TYPE_DATA_WR: 75 if (hw_breakpoint_enabled(dr7, index)) { 76 err = cpu_watchpoint_insert(cs, drN, 77 hw_breakpoint_len(dr7, index), 78 BP_CPU | BP_MEM_WRITE, 79 &env->cpu_watchpoint[index]); 80 } 81 break; 82 83 case DR7_TYPE_DATA_RW: 84 if (hw_breakpoint_enabled(dr7, index)) { 85 err = cpu_watchpoint_insert(cs, drN, 86 hw_breakpoint_len(dr7, index), 87 BP_CPU | BP_MEM_ACCESS, 88 &env->cpu_watchpoint[index]); 89 } 90 break; 91 } 92 if (err) { 93 env->cpu_breakpoint[index] = NULL; 94 } 95 return 0; 96 } 97 98 static void hw_breakpoint_remove(CPUX86State *env, int index) 99 { 100 CPUState *cs = env_cpu(env); 101 102 switch (hw_breakpoint_type(env->dr[7], index)) { 103 case DR7_TYPE_BP_INST: 104 if (env->cpu_breakpoint[index]) { 105 cpu_breakpoint_remove_by_ref(cs, env->cpu_breakpoint[index]); 106 env->cpu_breakpoint[index] = NULL; 107 } 108 break; 109 110 case DR7_TYPE_DATA_WR: 111 case DR7_TYPE_DATA_RW: 112 if (env->cpu_breakpoint[index]) { 113 cpu_watchpoint_remove_by_ref(cs, env->cpu_watchpoint[index]); 114 env->cpu_breakpoint[index] = NULL; 115 } 116 break; 117 118 case DR7_TYPE_IO_RW: 119 /* HF_IOBPT_MASK cleared elsewhere. */ 120 break; 121 } 122 } 123 124 void cpu_x86_update_dr7(CPUX86State *env, uint32_t new_dr7) 125 { 126 target_ulong old_dr7 = env->dr[7]; 127 int iobpt = 0; 128 int i; 129 130 new_dr7 |= DR7_FIXED_1; 131 132 /* If nothing is changing except the global/local enable bits, 133 then we can make the change more efficient. */ 134 if (((old_dr7 ^ new_dr7) & ~0xff) == 0) { 135 /* Fold the global and local enable bits together into the 136 global fields, then xor to show which registers have 137 changed collective enable state. */ 138 int mod = ((old_dr7 | old_dr7 * 2) ^ (new_dr7 | new_dr7 * 2)) & 0xff; 139 140 for (i = 0; i < DR7_MAX_BP; i++) { 141 if ((mod & (2 << i * 2)) && !hw_breakpoint_enabled(new_dr7, i)) { 142 hw_breakpoint_remove(env, i); 143 } 144 } 145 env->dr[7] = new_dr7; 146 for (i = 0; i < DR7_MAX_BP; i++) { 147 if (mod & (2 << i * 2) && hw_breakpoint_enabled(new_dr7, i)) { 148 iobpt |= hw_breakpoint_insert(env, i); 149 } else if (hw_breakpoint_type(new_dr7, i) == DR7_TYPE_IO_RW 150 && hw_breakpoint_enabled(new_dr7, i)) { 151 iobpt |= HF_IOBPT_MASK; 152 } 153 } 154 } else { 155 for (i = 0; i < DR7_MAX_BP; i++) { 156 hw_breakpoint_remove(env, i); 157 } 158 env->dr[7] = new_dr7; 159 for (i = 0; i < DR7_MAX_BP; i++) { 160 iobpt |= hw_breakpoint_insert(env, i); 161 } 162 } 163 164 env->hflags = (env->hflags & ~HF_IOBPT_MASK) | iobpt; 165 } 166 167 bool check_hw_breakpoints(CPUX86State *env, bool force_dr6_update) 168 { 169 target_ulong dr6; 170 int reg; 171 bool hit_enabled = false; 172 173 dr6 = env->dr[6] & ~0xf; 174 for (reg = 0; reg < DR7_MAX_BP; reg++) { 175 bool bp_match = false; 176 bool wp_match = false; 177 178 switch (hw_breakpoint_type(env->dr[7], reg)) { 179 case DR7_TYPE_BP_INST: 180 if (env->dr[reg] == env->eip) { 181 bp_match = true; 182 } 183 break; 184 case DR7_TYPE_DATA_WR: 185 case DR7_TYPE_DATA_RW: 186 if (env->cpu_watchpoint[reg] && 187 env->cpu_watchpoint[reg]->flags & BP_WATCHPOINT_HIT) { 188 wp_match = true; 189 } 190 break; 191 case DR7_TYPE_IO_RW: 192 break; 193 } 194 if (bp_match || wp_match) { 195 dr6 |= 1 << reg; 196 if (hw_breakpoint_enabled(env->dr[7], reg)) { 197 hit_enabled = true; 198 } 199 } 200 } 201 202 if (hit_enabled || force_dr6_update) { 203 env->dr[6] = dr6; 204 } 205 206 return hit_enabled; 207 } 208 209 void breakpoint_handler(CPUState *cs) 210 { 211 X86CPU *cpu = X86_CPU(cs); 212 CPUX86State *env = &cpu->env; 213 214 if (cs->watchpoint_hit) { 215 if (cs->watchpoint_hit->flags & BP_CPU) { 216 cs->watchpoint_hit = NULL; 217 if (check_hw_breakpoints(env, false)) { 218 raise_exception(env, EXCP01_DB); 219 } else { 220 cpu_loop_exit_noexc(cs); 221 } 222 } 223 } else { 224 if (cpu_breakpoint_test(cs, env->eip, BP_CPU)) { 225 check_hw_breakpoints(env, true); 226 raise_exception(env, EXCP01_DB); 227 } 228 } 229 } 230 231 void helper_set_dr(CPUX86State *env, int reg, target_ulong t0) 232 { 233 switch (reg) { 234 case 0: case 1: case 2: case 3: 235 if (hw_breakpoint_enabled(env->dr[7], reg) 236 && hw_breakpoint_type(env->dr[7], reg) != DR7_TYPE_IO_RW) { 237 hw_breakpoint_remove(env, reg); 238 env->dr[reg] = t0; 239 hw_breakpoint_insert(env, reg); 240 } else { 241 env->dr[reg] = t0; 242 } 243 return; 244 case 4: 245 if (env->cr[4] & CR4_DE_MASK) { 246 break; 247 } 248 /* fallthru */ 249 case 6: 250 env->dr[6] = t0 | DR6_FIXED_1; 251 return; 252 case 5: 253 if (env->cr[4] & CR4_DE_MASK) { 254 break; 255 } 256 /* fallthru */ 257 case 7: 258 cpu_x86_update_dr7(env, t0); 259 return; 260 } 261 raise_exception_err_ra(env, EXCP06_ILLOP, 0, GETPC()); 262 } 263 264 /* Check if Port I/O is trapped by a breakpoint. */ 265 void helper_bpt_io(CPUX86State *env, uint32_t port, 266 uint32_t size, target_ulong next_eip) 267 { 268 target_ulong dr7 = env->dr[7]; 269 int i, hit = 0; 270 271 for (i = 0; i < DR7_MAX_BP; ++i) { 272 if (hw_breakpoint_type(dr7, i) == DR7_TYPE_IO_RW 273 && hw_breakpoint_enabled(dr7, i)) { 274 int bpt_len = hw_breakpoint_len(dr7, i); 275 if (port + size - 1 >= env->dr[i] 276 && port <= env->dr[i] + bpt_len - 1) { 277 hit |= 1 << i; 278 } 279 } 280 } 281 282 if (hit) { 283 env->dr[6] = (env->dr[6] & ~0xf) | hit; 284 env->eip = next_eip; 285 raise_exception(env, EXCP01_DB); 286 } 287 } 288