1 /* 2 * qemu user cpu loop 3 * 4 * Copyright (c) 2003-2008 Fabrice Bellard 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program 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 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include "qemu/osdep.h" 21 #include "qemu-common.h" 22 #include "qemu.h" 23 #include "user-internals.h" 24 #include "cpu_loop-common.h" 25 #include "signal-common.h" 26 #include "user-mmap.h" 27 28 /***********************************************************/ 29 /* CPUX86 core interface */ 30 31 uint64_t cpu_get_tsc(CPUX86State *env) 32 { 33 return cpu_get_host_ticks(); 34 } 35 36 static void write_dt(void *ptr, unsigned long addr, unsigned long limit, 37 int flags) 38 { 39 unsigned int e1, e2; 40 uint32_t *p; 41 e1 = (addr << 16) | (limit & 0xffff); 42 e2 = ((addr >> 16) & 0xff) | (addr & 0xff000000) | (limit & 0x000f0000); 43 e2 |= flags; 44 p = ptr; 45 p[0] = tswap32(e1); 46 p[1] = tswap32(e2); 47 } 48 49 static uint64_t *idt_table; 50 #ifdef TARGET_X86_64 51 static void set_gate64(void *ptr, unsigned int type, unsigned int dpl, 52 uint64_t addr, unsigned int sel) 53 { 54 uint32_t *p, e1, e2; 55 e1 = (addr & 0xffff) | (sel << 16); 56 e2 = (addr & 0xffff0000) | 0x8000 | (dpl << 13) | (type << 8); 57 p = ptr; 58 p[0] = tswap32(e1); 59 p[1] = tswap32(e2); 60 p[2] = tswap32(addr >> 32); 61 p[3] = 0; 62 } 63 /* only dpl matters as we do only user space emulation */ 64 static void set_idt(int n, unsigned int dpl) 65 { 66 set_gate64(idt_table + n * 2, 0, dpl, 0, 0); 67 } 68 #else 69 static void set_gate(void *ptr, unsigned int type, unsigned int dpl, 70 uint32_t addr, unsigned int sel) 71 { 72 uint32_t *p, e1, e2; 73 e1 = (addr & 0xffff) | (sel << 16); 74 e2 = (addr & 0xffff0000) | 0x8000 | (dpl << 13) | (type << 8); 75 p = ptr; 76 p[0] = tswap32(e1); 77 p[1] = tswap32(e2); 78 } 79 80 /* only dpl matters as we do only user space emulation */ 81 static void set_idt(int n, unsigned int dpl) 82 { 83 set_gate(idt_table + n, 0, dpl, 0, 0); 84 } 85 #endif 86 87 static void gen_signal(CPUX86State *env, int sig, int code, abi_ptr addr) 88 { 89 target_siginfo_t info = { 90 .si_signo = sig, 91 .si_code = code, 92 ._sifields._sigfault._addr = addr 93 }; 94 95 queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info); 96 } 97 98 #ifdef TARGET_X86_64 99 static bool write_ok_or_segv(CPUX86State *env, abi_ptr addr, size_t len) 100 { 101 /* 102 * For all the vsyscalls, NULL means "don't write anything" not 103 * "write it at address 0". 104 */ 105 if (addr == 0 || access_ok(env_cpu(env), VERIFY_WRITE, addr, len)) { 106 return true; 107 } 108 109 env->error_code = PG_ERROR_W_MASK | PG_ERROR_U_MASK; 110 gen_signal(env, TARGET_SIGSEGV, TARGET_SEGV_MAPERR, addr); 111 return false; 112 } 113 114 /* 115 * Since v3.1, the kernel traps and emulates the vsyscall page. 116 * Entry points other than the official generate SIGSEGV. 117 */ 118 static void emulate_vsyscall(CPUX86State *env) 119 { 120 int syscall; 121 abi_ulong ret; 122 uint64_t caller; 123 124 /* 125 * Validate the entry point. We have already validated the page 126 * during translation to get here; now verify the offset. 127 */ 128 switch (env->eip & ~TARGET_PAGE_MASK) { 129 case 0x000: 130 syscall = TARGET_NR_gettimeofday; 131 break; 132 case 0x400: 133 syscall = TARGET_NR_time; 134 break; 135 case 0x800: 136 syscall = TARGET_NR_getcpu; 137 break; 138 default: 139 goto sigsegv; 140 } 141 142 /* 143 * Validate the return address. 144 * Note that the kernel treats this the same as an invalid entry point. 145 */ 146 if (get_user_u64(caller, env->regs[R_ESP])) { 147 goto sigsegv; 148 } 149 150 /* 151 * Validate the the pointer arguments. 152 */ 153 switch (syscall) { 154 case TARGET_NR_gettimeofday: 155 if (!write_ok_or_segv(env, env->regs[R_EDI], 156 sizeof(struct target_timeval)) || 157 !write_ok_or_segv(env, env->regs[R_ESI], 158 sizeof(struct target_timezone))) { 159 return; 160 } 161 break; 162 case TARGET_NR_time: 163 if (!write_ok_or_segv(env, env->regs[R_EDI], sizeof(abi_long))) { 164 return; 165 } 166 break; 167 case TARGET_NR_getcpu: 168 if (!write_ok_or_segv(env, env->regs[R_EDI], sizeof(uint32_t)) || 169 !write_ok_or_segv(env, env->regs[R_ESI], sizeof(uint32_t))) { 170 return; 171 } 172 break; 173 default: 174 g_assert_not_reached(); 175 } 176 177 /* 178 * Perform the syscall. None of the vsyscalls should need restarting. 179 */ 180 ret = do_syscall(env, syscall, env->regs[R_EDI], env->regs[R_ESI], 181 env->regs[R_EDX], env->regs[10], env->regs[8], 182 env->regs[9], 0, 0); 183 g_assert(ret != -QEMU_ERESTARTSYS); 184 g_assert(ret != -QEMU_ESIGRETURN); 185 if (ret == -TARGET_EFAULT) { 186 goto sigsegv; 187 } 188 env->regs[R_EAX] = ret; 189 190 /* Emulate a ret instruction to leave the vsyscall page. */ 191 env->eip = caller; 192 env->regs[R_ESP] += 8; 193 return; 194 195 sigsegv: 196 /* Like force_sig(SIGSEGV). */ 197 gen_signal(env, TARGET_SIGSEGV, TARGET_SI_KERNEL, 0); 198 } 199 #endif 200 201 void cpu_loop(CPUX86State *env) 202 { 203 CPUState *cs = env_cpu(env); 204 int trapnr; 205 abi_ulong pc; 206 abi_ulong ret; 207 208 for(;;) { 209 cpu_exec_start(cs); 210 trapnr = cpu_exec(cs); 211 cpu_exec_end(cs); 212 process_queued_cpu_work(cs); 213 214 switch(trapnr) { 215 case 0x80: 216 /* linux syscall from int $0x80 */ 217 ret = do_syscall(env, 218 env->regs[R_EAX], 219 env->regs[R_EBX], 220 env->regs[R_ECX], 221 env->regs[R_EDX], 222 env->regs[R_ESI], 223 env->regs[R_EDI], 224 env->regs[R_EBP], 225 0, 0); 226 if (ret == -QEMU_ERESTARTSYS) { 227 env->eip -= 2; 228 } else if (ret != -QEMU_ESIGRETURN) { 229 env->regs[R_EAX] = ret; 230 } 231 break; 232 #ifndef TARGET_ABI32 233 case EXCP_SYSCALL: 234 /* linux syscall from syscall instruction */ 235 ret = do_syscall(env, 236 env->regs[R_EAX], 237 env->regs[R_EDI], 238 env->regs[R_ESI], 239 env->regs[R_EDX], 240 env->regs[10], 241 env->regs[8], 242 env->regs[9], 243 0, 0); 244 if (ret == -QEMU_ERESTARTSYS) { 245 env->eip -= 2; 246 } else if (ret != -QEMU_ESIGRETURN) { 247 env->regs[R_EAX] = ret; 248 } 249 break; 250 #endif 251 #ifdef TARGET_X86_64 252 case EXCP_VSYSCALL: 253 emulate_vsyscall(env); 254 break; 255 #endif 256 case EXCP0B_NOSEG: 257 case EXCP0C_STACK: 258 gen_signal(env, TARGET_SIGBUS, TARGET_SI_KERNEL, 0); 259 break; 260 case EXCP0D_GPF: 261 /* XXX: potential problem if ABI32 */ 262 #ifndef TARGET_X86_64 263 if (env->eflags & VM_MASK) { 264 handle_vm86_fault(env); 265 break; 266 } 267 #endif 268 gen_signal(env, TARGET_SIGSEGV, TARGET_SI_KERNEL, 0); 269 break; 270 case EXCP0E_PAGE: 271 gen_signal(env, TARGET_SIGSEGV, 272 (env->error_code & 1 ? 273 TARGET_SEGV_ACCERR : TARGET_SEGV_MAPERR), 274 env->cr[2]); 275 break; 276 case EXCP00_DIVZ: 277 #ifndef TARGET_X86_64 278 if (env->eflags & VM_MASK) { 279 handle_vm86_trap(env, trapnr); 280 break; 281 } 282 #endif 283 gen_signal(env, TARGET_SIGFPE, TARGET_FPE_INTDIV, env->eip); 284 break; 285 case EXCP01_DB: 286 case EXCP03_INT3: 287 #ifndef TARGET_X86_64 288 if (env->eflags & VM_MASK) { 289 handle_vm86_trap(env, trapnr); 290 break; 291 } 292 #endif 293 if (trapnr == EXCP01_DB) { 294 gen_signal(env, TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->eip); 295 } else { 296 gen_signal(env, TARGET_SIGTRAP, TARGET_SI_KERNEL, 0); 297 } 298 break; 299 case EXCP04_INTO: 300 case EXCP05_BOUND: 301 #ifndef TARGET_X86_64 302 if (env->eflags & VM_MASK) { 303 handle_vm86_trap(env, trapnr); 304 break; 305 } 306 #endif 307 gen_signal(env, TARGET_SIGSEGV, TARGET_SI_KERNEL, 0); 308 break; 309 case EXCP06_ILLOP: 310 gen_signal(env, TARGET_SIGILL, TARGET_ILL_ILLOPN, env->eip); 311 break; 312 case EXCP_INTERRUPT: 313 /* just indicate that signals should be handled asap */ 314 break; 315 case EXCP_DEBUG: 316 gen_signal(env, TARGET_SIGTRAP, TARGET_TRAP_BRKPT, 0); 317 break; 318 case EXCP_ATOMIC: 319 cpu_exec_step_atomic(cs); 320 break; 321 default: 322 pc = env->segs[R_CS].base + env->eip; 323 EXCP_DUMP(env, "qemu: 0x%08lx: unhandled CPU exception 0x%x - aborting\n", 324 (long)pc, trapnr); 325 abort(); 326 } 327 process_pending_signals(env); 328 } 329 } 330 331 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs) 332 { 333 env->cr[0] = CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK; 334 env->hflags |= HF_PE_MASK | HF_CPL_MASK; 335 if (env->features[FEAT_1_EDX] & CPUID_SSE) { 336 env->cr[4] |= CR4_OSFXSR_MASK; 337 env->hflags |= HF_OSFXSR_MASK; 338 } 339 #ifndef TARGET_ABI32 340 /* enable 64 bit mode if possible */ 341 if (!(env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_LM)) { 342 fprintf(stderr, "The selected x86 CPU does not support 64 bit mode\n"); 343 exit(EXIT_FAILURE); 344 } 345 env->cr[4] |= CR4_PAE_MASK; 346 env->efer |= MSR_EFER_LMA | MSR_EFER_LME; 347 env->hflags |= HF_LMA_MASK; 348 #endif 349 350 /* flags setup : we activate the IRQs by default as in user mode */ 351 env->eflags |= IF_MASK; 352 353 /* linux register setup */ 354 #ifndef TARGET_ABI32 355 env->regs[R_EAX] = regs->rax; 356 env->regs[R_EBX] = regs->rbx; 357 env->regs[R_ECX] = regs->rcx; 358 env->regs[R_EDX] = regs->rdx; 359 env->regs[R_ESI] = regs->rsi; 360 env->regs[R_EDI] = regs->rdi; 361 env->regs[R_EBP] = regs->rbp; 362 env->regs[R_ESP] = regs->rsp; 363 env->eip = regs->rip; 364 #else 365 env->regs[R_EAX] = regs->eax; 366 env->regs[R_EBX] = regs->ebx; 367 env->regs[R_ECX] = regs->ecx; 368 env->regs[R_EDX] = regs->edx; 369 env->regs[R_ESI] = regs->esi; 370 env->regs[R_EDI] = regs->edi; 371 env->regs[R_EBP] = regs->ebp; 372 env->regs[R_ESP] = regs->esp; 373 env->eip = regs->eip; 374 #endif 375 376 /* linux interrupt setup */ 377 #ifndef TARGET_ABI32 378 env->idt.limit = 511; 379 #else 380 env->idt.limit = 255; 381 #endif 382 env->idt.base = target_mmap(0, sizeof(uint64_t) * (env->idt.limit + 1), 383 PROT_READ|PROT_WRITE, 384 MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); 385 idt_table = g2h_untagged(env->idt.base); 386 set_idt(0, 0); 387 set_idt(1, 0); 388 set_idt(2, 0); 389 set_idt(3, 3); 390 set_idt(4, 3); 391 set_idt(5, 0); 392 set_idt(6, 0); 393 set_idt(7, 0); 394 set_idt(8, 0); 395 set_idt(9, 0); 396 set_idt(10, 0); 397 set_idt(11, 0); 398 set_idt(12, 0); 399 set_idt(13, 0); 400 set_idt(14, 0); 401 set_idt(15, 0); 402 set_idt(16, 0); 403 set_idt(17, 0); 404 set_idt(18, 0); 405 set_idt(19, 0); 406 set_idt(0x80, 3); 407 408 /* linux segment setup */ 409 { 410 uint64_t *gdt_table; 411 env->gdt.base = target_mmap(0, sizeof(uint64_t) * TARGET_GDT_ENTRIES, 412 PROT_READ|PROT_WRITE, 413 MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); 414 env->gdt.limit = sizeof(uint64_t) * TARGET_GDT_ENTRIES - 1; 415 gdt_table = g2h_untagged(env->gdt.base); 416 #ifdef TARGET_ABI32 417 write_dt(&gdt_table[__USER_CS >> 3], 0, 0xfffff, 418 DESC_G_MASK | DESC_B_MASK | DESC_P_MASK | DESC_S_MASK | 419 (3 << DESC_DPL_SHIFT) | (0xa << DESC_TYPE_SHIFT)); 420 #else 421 /* 64 bit code segment */ 422 write_dt(&gdt_table[__USER_CS >> 3], 0, 0xfffff, 423 DESC_G_MASK | DESC_B_MASK | DESC_P_MASK | DESC_S_MASK | 424 DESC_L_MASK | 425 (3 << DESC_DPL_SHIFT) | (0xa << DESC_TYPE_SHIFT)); 426 #endif 427 write_dt(&gdt_table[__USER_DS >> 3], 0, 0xfffff, 428 DESC_G_MASK | DESC_B_MASK | DESC_P_MASK | DESC_S_MASK | 429 (3 << DESC_DPL_SHIFT) | (0x2 << DESC_TYPE_SHIFT)); 430 } 431 cpu_x86_load_seg(env, R_CS, __USER_CS); 432 cpu_x86_load_seg(env, R_SS, __USER_DS); 433 #ifdef TARGET_ABI32 434 cpu_x86_load_seg(env, R_DS, __USER_DS); 435 cpu_x86_load_seg(env, R_ES, __USER_DS); 436 cpu_x86_load_seg(env, R_FS, __USER_DS); 437 cpu_x86_load_seg(env, R_GS, __USER_DS); 438 /* This hack makes Wine work... */ 439 env->segs[R_FS].selector = 0; 440 #else 441 cpu_x86_load_seg(env, R_DS, 0); 442 cpu_x86_load_seg(env, R_ES, 0); 443 cpu_x86_load_seg(env, R_FS, 0); 444 cpu_x86_load_seg(env, R_GS, 0); 445 #endif 446 } 447