user-exec.c

   1 /*
   2  *  User emulator execution
   3  *
   4  *  Copyright (c) 2003-2005 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 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 #include "qemu/osdep.h"
  20 #include "cpu.h"
  21 #include "disas/disas.h"
  22 #include "exec/exec-all.h"
  23 #include "tcg.h"
  24 #include "qemu/bitops.h"
  25 #include "exec/cpu_ldst.h"
  26 #include "translate-all.h"
  27
  28 #undef EAX
  29 #undef ECX
  30 #undef EDX
  31 #undef EBX
  32 #undef ESP
  33 #undef EBP
  34 #undef ESI
  35 #undef EDI
  36 #undef EIP
  37 #ifdef __linux__
  38 #include <sys/ucontext.h>
  39 #endif
  40
  41 //#define DEBUG_SIGNAL
  42
  43 /* exit the current TB from a signal handler. The host registers are
  44    restored in a state compatible with the CPU emulator
  45  */
  46 static void cpu_exit_tb_from_sighandler(CPUState *cpu, sigset_t *old_set)
  47 {
  48     /* XXX: use siglongjmp ? */
  49     sigprocmask(SIG_SETMASK, old_set, NULL);
  50     cpu_loop_exit_noexc(cpu);
  51 }
  52
  53 /* 'pc' is the host PC at which the exception was raised. 'address' is
  54    the effective address of the memory exception. 'is_write' is 1 if a
  55    write caused the exception and otherwise 0'. 'old_set' is the
  56    signal set which should be restored */
  57 static inline int handle_cpu_signal(uintptr_t pc, unsigned long address,
  58                                     int is_write, sigset_t *old_set)
  59 {
  60     CPUState *cpu = current_cpu;
  61     CPUClass *cc;
  62     int ret;
  63
  64     /* For synchronous signals we expect to be coming from the vCPU
  65      * thread (so current_cpu should be valid) and either from running
  66      * code or during translation which can fault as we cross pages.
  67      *
  68      * If neither is true then something has gone wrong and we should
  69      * abort rather than try and restart the vCPU execution.
  70      */
  71     if (!cpu || !cpu->running) {
  72         printf("qemu:%s received signal outside vCPU context @ pc=0x%"
  73                PRIxPTR "\n",  __func__, pc);
  74         abort();
  75     }
  76
  77 #if defined(DEBUG_SIGNAL)
  78     printf("qemu: SIGSEGV pc=0x%08lx address=%08lx w=%d oldset=0x%08lx\n",
  79            pc, address, is_write, *(unsigned long *)old_set);
  80 #endif
  81     /* XXX: locking issue */
  82     if (is_write && h2g_valid(address)) {
  83         switch (page_unprotect(h2g(address), pc)) {
  84         case 0:
  85             /* Fault not caused by a page marked unwritable to protect
  86              * cached translations, must be the guest binary's problem
  87              */
  88             break;
  89         case 1:
  90             /* Fault caused by protection of cached translation; TBs
  91              * invalidated, so resume execution
  92              */
  93             return 1;
  94         case 2:
  95             /* Fault caused by protection of cached translation, and the
  96              * currently executing TB was modified and must be exited
  97              * immediately.
  98              */
  99             cpu_exit_tb_from_sighandler(cpu, old_set);
 100             g_assert_not_reached();
 101         default:
 102             g_assert_not_reached();
 103         }
 104     }
 105
 106     /* Convert forcefully to guest address space, invalid addresses
 107        are still valid segv ones */
 108     address = h2g_nocheck(address);
 109
 110     cc = CPU_GET_CLASS(cpu);
 111     /* see if it is an MMU fault */
 112     g_assert(cc->handle_mmu_fault);
 113     ret = cc->handle_mmu_fault(cpu, address, is_write, MMU_USER_IDX);
 114     if (ret < 0) {
 115         return 0; /* not an MMU fault */
 116     }
 117     if (ret == 0) {
 118         return 1; /* the MMU fault was handled without causing real CPU fault */
 119     }
 120
 121     /* Now we have a real cpu fault.  Since this is the exact location of
 122      * the exception, we must undo the adjustment done by cpu_restore_state
 123      * for handling call return addresses.  */
 124     cpu_restore_state(cpu, pc + GETPC_ADJ);
 125
 126     sigprocmask(SIG_SETMASK, old_set, NULL);
 127     cpu_loop_exit(cpu);
 128
 129     /* never comes here */
 130     return 1;
 131 }
 132
 133 #if defined(__i386__)
 134
 135 #if defined(__NetBSD__)
 136 #include <ucontext.h>
 137
 138 #define EIP_sig(context)     ((context)->uc_mcontext.__gregs[_REG_EIP])
 139 #define TRAP_sig(context)    ((context)->uc_mcontext.__gregs[_REG_TRAPNO])
 140 #define ERROR_sig(context)   ((context)->uc_mcontext.__gregs[_REG_ERR])
 141 #define MASK_sig(context)    ((context)->uc_sigmask)
 142 #elif defined(__FreeBSD__) || defined(__DragonFly__)
 143 #include <ucontext.h>
 144
 145 #define EIP_sig(context)  (*((unsigned long *)&(context)->uc_mcontext.mc_eip))
 146 #define TRAP_sig(context)    ((context)->uc_mcontext.mc_trapno)
 147 #define ERROR_sig(context)   ((context)->uc_mcontext.mc_err)
 148 #define MASK_sig(context)    ((context)->uc_sigmask)
 149 #elif defined(__OpenBSD__)
 150 #define EIP_sig(context)     ((context)->sc_eip)
 151 #define TRAP_sig(context)    ((context)->sc_trapno)
 152 #define ERROR_sig(context)   ((context)->sc_err)
 153 #define MASK_sig(context)    ((context)->sc_mask)
 154 #else
 155 #define EIP_sig(context)     ((context)->uc_mcontext.gregs[REG_EIP])
 156 #define TRAP_sig(context)    ((context)->uc_mcontext.gregs[REG_TRAPNO])
 157 #define ERROR_sig(context)   ((context)->uc_mcontext.gregs[REG_ERR])
 158 #define MASK_sig(context)    ((context)->uc_sigmask)
 159 #endif
 160
 161 int cpu_signal_handler(int host_signum, void *pinfo,
 162                        void *puc)
 163 {
 164     siginfo_t *info = pinfo;
 165 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
 166     ucontext_t *uc = puc;
 167 #elif defined(__OpenBSD__)
 168     struct sigcontext *uc = puc;
 169 #else
 170     struct ucontext *uc = puc;
 171 #endif
 172     unsigned long pc;
 173     int trapno;
 174
 175 #ifndef REG_EIP
 176 /* for glibc 2.1 */
 177 #define REG_EIP    EIP
 178 #define REG_ERR    ERR
 179 #define REG_TRAPNO TRAPNO
 180 #endif
 181     pc = EIP_sig(uc);
 182     trapno = TRAP_sig(uc);
 183     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 184                              trapno == 0xe ?
 185                              (ERROR_sig(uc) >> 1) & 1 : 0,
 186                              &MASK_sig(uc));
 187 }
 188
 189 #elif defined(__x86_64__)
 190
 191 #ifdef __NetBSD__
 192 #define PC_sig(context)       _UC_MACHINE_PC(context)
 193 #define TRAP_sig(context)     ((context)->uc_mcontext.__gregs[_REG_TRAPNO])
 194 #define ERROR_sig(context)    ((context)->uc_mcontext.__gregs[_REG_ERR])
 195 #define MASK_sig(context)     ((context)->uc_sigmask)
 196 #elif defined(__OpenBSD__)
 197 #define PC_sig(context)       ((context)->sc_rip)
 198 #define TRAP_sig(context)     ((context)->sc_trapno)
 199 #define ERROR_sig(context)    ((context)->sc_err)
 200 #define MASK_sig(context)     ((context)->sc_mask)
 201 #elif defined(__FreeBSD__) || defined(__DragonFly__)
 202 #include <ucontext.h>
 203
 204 #define PC_sig(context)  (*((unsigned long *)&(context)->uc_mcontext.mc_rip))
 205 #define TRAP_sig(context)     ((context)->uc_mcontext.mc_trapno)
 206 #define ERROR_sig(context)    ((context)->uc_mcontext.mc_err)
 207 #define MASK_sig(context)     ((context)->uc_sigmask)
 208 #else
 209 #define PC_sig(context)       ((context)->uc_mcontext.gregs[REG_RIP])
 210 #define TRAP_sig(context)     ((context)->uc_mcontext.gregs[REG_TRAPNO])
 211 #define ERROR_sig(context)    ((context)->uc_mcontext.gregs[REG_ERR])
 212 #define MASK_sig(context)     ((context)->uc_sigmask)
 213 #endif
 214
 215 int cpu_signal_handler(int host_signum, void *pinfo,
 216                        void *puc)
 217 {
 218     siginfo_t *info = pinfo;
 219     unsigned long pc;
 220 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
 221     ucontext_t *uc = puc;
 222 #elif defined(__OpenBSD__)
 223     struct sigcontext *uc = puc;
 224 #else
 225     struct ucontext *uc = puc;
 226 #endif
 227
 228     pc = PC_sig(uc);
 229     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 230                              TRAP_sig(uc) == 0xe ?
 231                              (ERROR_sig(uc) >> 1) & 1 : 0,
 232                              &MASK_sig(uc));
 233 }
 234
 235 #elif defined(_ARCH_PPC)
 236
 237 /***********************************************************************
 238  * signal context platform-specific definitions
 239  * From Wine
 240  */
 241 #ifdef linux
 242 /* All Registers access - only for local access */
 243 #define REG_sig(reg_name, context)              \
 244     ((context)->uc_mcontext.regs->reg_name)
 245 /* Gpr Registers access  */
 246 #define GPR_sig(reg_num, context)              REG_sig(gpr[reg_num], context)
 247 /* Program counter */
 248 #define IAR_sig(context)                       REG_sig(nip, context)
 249 /* Machine State Register (Supervisor) */
 250 #define MSR_sig(context)                       REG_sig(msr, context)
 251 /* Count register */
 252 #define CTR_sig(context)                       REG_sig(ctr, context)
 253 /* User's integer exception register */
 254 #define XER_sig(context)                       REG_sig(xer, context)
 255 /* Link register */
 256 #define LR_sig(context)                        REG_sig(link, context)
 257 /* Condition register */
 258 #define CR_sig(context)                        REG_sig(ccr, context)
 259
 260 /* Float Registers access  */
 261 #define FLOAT_sig(reg_num, context)                                     \
 262     (((double *)((char *)((context)->uc_mcontext.regs + 48 * 4)))[reg_num])
 263 #define FPSCR_sig(context) \
 264     (*(int *)((char *)((context)->uc_mcontext.regs + (48 + 32 * 2) * 4)))
 265 /* Exception Registers access */
 266 #define DAR_sig(context)                       REG_sig(dar, context)
 267 #define DSISR_sig(context)                     REG_sig(dsisr, context)
 268 #define TRAP_sig(context)                      REG_sig(trap, context)
 269 #endif /* linux */
 270
 271 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
 272 #include <ucontext.h>
 273 #define IAR_sig(context)               ((context)->uc_mcontext.mc_srr0)
 274 #define MSR_sig(context)               ((context)->uc_mcontext.mc_srr1)
 275 #define CTR_sig(context)               ((context)->uc_mcontext.mc_ctr)
 276 #define XER_sig(context)               ((context)->uc_mcontext.mc_xer)
 277 #define LR_sig(context)                ((context)->uc_mcontext.mc_lr)
 278 #define CR_sig(context)                ((context)->uc_mcontext.mc_cr)
 279 /* Exception Registers access */
 280 #define DAR_sig(context)               ((context)->uc_mcontext.mc_dar)
 281 #define DSISR_sig(context)             ((context)->uc_mcontext.mc_dsisr)
 282 #define TRAP_sig(context)              ((context)->uc_mcontext.mc_exc)
 283 #endif /* __FreeBSD__|| __FreeBSD_kernel__ */
 284
 285 int cpu_signal_handler(int host_signum, void *pinfo,
 286                        void *puc)
 287 {
 288     siginfo_t *info = pinfo;
 289 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
 290     ucontext_t *uc = puc;
 291 #else
 292     struct ucontext *uc = puc;
 293 #endif
 294     unsigned long pc;
 295     int is_write;
 296
 297     pc = IAR_sig(uc);
 298     is_write = 0;
 299 #if 0
 300     /* ppc 4xx case */
 301     if (DSISR_sig(uc) & 0x00800000) {
 302         is_write = 1;
 303     }
 304 #else
 305     if (TRAP_sig(uc) != 0x400 && (DSISR_sig(uc) & 0x02000000)) {
 306         is_write = 1;
 307     }
 308 #endif
 309     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 310                              is_write, &uc->uc_sigmask);
 311 }
 312
 313 #elif defined(__alpha__)
 314
 315 int cpu_signal_handler(int host_signum, void *pinfo,
 316                            void *puc)
 317 {
 318     siginfo_t *info = pinfo;
 319     struct ucontext *uc = puc;
 320     uint32_t *pc = uc->uc_mcontext.sc_pc;
 321     uint32_t insn = *pc;
 322     int is_write = 0;
 323
 324     /* XXX: need kernel patch to get write flag faster */
 325     switch (insn >> 26) {
 326     case 0x0d: /* stw */
 327     case 0x0e: /* stb */
 328     case 0x0f: /* stq_u */
 329     case 0x24: /* stf */
 330     case 0x25: /* stg */
 331     case 0x26: /* sts */
 332     case 0x27: /* stt */
 333     case 0x2c: /* stl */
 334     case 0x2d: /* stq */
 335     case 0x2e: /* stl_c */
 336     case 0x2f: /* stq_c */
 337         is_write = 1;
 338     }
 339
 340     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 341                              is_write, &uc->uc_sigmask);
 342 }
 343 #elif defined(__sparc__)
 344
 345 int cpu_signal_handler(int host_signum, void *pinfo,
 346                        void *puc)
 347 {
 348     siginfo_t *info = pinfo;
 349     int is_write;
 350     uint32_t insn;
 351 #if !defined(__arch64__) || defined(CONFIG_SOLARIS)
 352     uint32_t *regs = (uint32_t *)(info + 1);
 353     void *sigmask = (regs + 20);
 354     /* XXX: is there a standard glibc define ? */
 355     unsigned long pc = regs[1];
 356 #else
 357 #ifdef __linux__
 358     struct sigcontext *sc = puc;
 359     unsigned long pc = sc->sigc_regs.tpc;
 360     void *sigmask = (void *)sc->sigc_mask;
 361 #elif defined(__OpenBSD__)
 362     struct sigcontext *uc = puc;
 363     unsigned long pc = uc->sc_pc;
 364     void *sigmask = (void *)(long)uc->sc_mask;
 365 #elif defined(__NetBSD__)
 366     ucontext_t *uc = puc;
 367     unsigned long pc = _UC_MACHINE_PC(uc);
 368     void *sigmask = (void *)&uc->uc_sigmask;
 369 #endif
 370 #endif
 371
 372     /* XXX: need kernel patch to get write flag faster */
 373     is_write = 0;
 374     insn = *(uint32_t *)pc;
 375     if ((insn >> 30) == 3) {
 376         switch ((insn >> 19) & 0x3f) {
 377         case 0x05: /* stb */
 378         case 0x15: /* stba */
 379         case 0x06: /* sth */
 380         case 0x16: /* stha */
 381         case 0x04: /* st */
 382         case 0x14: /* sta */
 383         case 0x07: /* std */
 384         case 0x17: /* stda */
 385         case 0x0e: /* stx */
 386         case 0x1e: /* stxa */
 387         case 0x24: /* stf */
 388         case 0x34: /* stfa */
 389         case 0x27: /* stdf */
 390         case 0x37: /* stdfa */
 391         case 0x26: /* stqf */
 392         case 0x36: /* stqfa */
 393         case 0x25: /* stfsr */
 394         case 0x3c: /* casa */
 395         case 0x3e: /* casxa */
 396             is_write = 1;
 397             break;
 398         }
 399     }
 400     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 401                              is_write, sigmask);
 402 }
 403
 404 #elif defined(__arm__)
 405
 406 #if defined(__NetBSD__)
 407 #include <ucontext.h>
 408 #endif
 409
 410 int cpu_signal_handler(int host_signum, void *pinfo,
 411                        void *puc)
 412 {
 413     siginfo_t *info = pinfo;
 414 #if defined(__NetBSD__)
 415     ucontext_t *uc = puc;
 416 #else
 417     struct ucontext *uc = puc;
 418 #endif
 419     unsigned long pc;
 420     int is_write;
 421
 422 #if defined(__NetBSD__)
 423     pc = uc->uc_mcontext.__gregs[_REG_R15];
 424 #elif defined(__GLIBC__) && (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
 425     pc = uc->uc_mcontext.gregs[R15];
 426 #else
 427     pc = uc->uc_mcontext.arm_pc;
 428 #endif
 429
 430     /* error_code is the FSR value, in which bit 11 is WnR (assuming a v6 or
 431      * later processor; on v5 we will always report this as a read).
 432      */
 433     is_write = extract32(uc->uc_mcontext.error_code, 11, 1);
 434     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 435                              is_write,
 436                              &uc->uc_sigmask);
 437 }
 438
 439 #elif defined(__aarch64__)
 440
 441 int cpu_signal_handler(int host_signum, void *pinfo, void *puc)
 442 {
 443     siginfo_t *info = pinfo;
 444     struct ucontext *uc = puc;
 445     uintptr_t pc = uc->uc_mcontext.pc;
 446     uint32_t insn = *(uint32_t *)pc;
 447     bool is_write;
 448
 449     /* XXX: need kernel patch to get write flag faster.  */
 450     is_write = (   (insn & 0xbfff0000) == 0x0c000000   /* C3.3.1 */
 451                 || (insn & 0xbfe00000) == 0x0c800000   /* C3.3.2 */
 452                 || (insn & 0xbfdf0000) == 0x0d000000   /* C3.3.3 */
 453                 || (insn & 0xbfc00000) == 0x0d800000   /* C3.3.4 */
 454                 || (insn & 0x3f400000) == 0x08000000   /* C3.3.6 */
 455                 || (insn & 0x3bc00000) == 0x39000000   /* C3.3.13 */
 456                 || (insn & 0x3fc00000) == 0x3d800000   /* ... 128bit */
 457                 /* Ingore bits 10, 11 & 21, controlling indexing.  */
 458                 || (insn & 0x3bc00000) == 0x38000000   /* C3.3.8-12 */
 459                 || (insn & 0x3fe00000) == 0x3c800000   /* ... 128bit */
 460                 /* Ignore bits 23 & 24, controlling indexing.  */
 461                 || (insn & 0x3a400000) == 0x28000000); /* C3.3.7,14-16 */
 462
 463     return handle_cpu_signal(pc, (uintptr_t)info->si_addr,
 464                              is_write, &uc->uc_sigmask);
 465 }
 466
 467 #elif defined(__ia64)
 468
 469 #ifndef __ISR_VALID
 470   /* This ought to be in <bits/siginfo.h>... */
 471 # define __ISR_VALID    1
 472 #endif
 473
 474 int cpu_signal_handler(int host_signum, void *pinfo, void *puc)
 475 {
 476     siginfo_t *info = pinfo;
 477     struct ucontext *uc = puc;
 478     unsigned long ip;
 479     int is_write = 0;
 480
 481     ip = uc->uc_mcontext.sc_ip;
 482     switch (host_signum) {
 483     case SIGILL:
 484     case SIGFPE:
 485     case SIGSEGV:
 486     case SIGBUS:
 487     case SIGTRAP:
 488         if (info->si_code && (info->si_segvflags & __ISR_VALID)) {
 489             /* ISR.W (write-access) is bit 33:  */
 490             is_write = (info->si_isr >> 33) & 1;
 491         }
 492         break;
 493
 494     default:
 495         break;
 496     }
 497     return handle_cpu_signal(ip, (unsigned long)info->si_addr,
 498                              is_write,
 499                              (sigset_t *)&uc->uc_sigmask);
 500 }
 501
 502 #elif defined(__s390__)
 503
 504 int cpu_signal_handler(int host_signum, void *pinfo,
 505                        void *puc)
 506 {
 507     siginfo_t *info = pinfo;
 508     struct ucontext *uc = puc;
 509     unsigned long pc;
 510     uint16_t *pinsn;
 511     int is_write = 0;
 512
 513     pc = uc->uc_mcontext.psw.addr;
 514
 515     /* ??? On linux, the non-rt signal handler has 4 (!) arguments instead
 516        of the normal 2 arguments.  The 3rd argument contains the "int_code"
 517        from the hardware which does in fact contain the is_write value.
 518        The rt signal handler, as far as I can tell, does not give this value
 519        at all.  Not that we could get to it from here even if it were.  */
 520     /* ??? This is not even close to complete, since it ignores all
 521        of the read-modify-write instructions.  */
 522     pinsn = (uint16_t *)pc;
 523     switch (pinsn[0] >> 8) {
 524     case 0x50: /* ST */
 525     case 0x42: /* STC */
 526     case 0x40: /* STH */
 527         is_write = 1;
 528         break;
 529     case 0xc4: /* RIL format insns */
 530         switch (pinsn[0] & 0xf) {
 531         case 0xf: /* STRL */
 532         case 0xb: /* STGRL */
 533         case 0x7: /* STHRL */
 534             is_write = 1;
 535         }
 536         break;
 537     case 0xe3: /* RXY format insns */
 538         switch (pinsn[2] & 0xff) {
 539         case 0x50: /* STY */
 540         case 0x24: /* STG */
 541         case 0x72: /* STCY */
 542         case 0x70: /* STHY */
 543         case 0x8e: /* STPQ */
 544         case 0x3f: /* STRVH */
 545         case 0x3e: /* STRV */
 546         case 0x2f: /* STRVG */
 547             is_write = 1;
 548         }
 549         break;
 550     }
 551     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 552                              is_write, &uc->uc_sigmask);
 553 }
 554
 555 #elif defined(__mips__)
 556
 557 int cpu_signal_handler(int host_signum, void *pinfo,
 558                        void *puc)
 559 {
 560     siginfo_t *info = pinfo;
 561     struct ucontext *uc = puc;
 562     greg_t pc = uc->uc_mcontext.pc;
 563     int is_write;
 564
 565     /* XXX: compute is_write */
 566     is_write = 0;
 567     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 568                              is_write, &uc->uc_sigmask);
 569 }
 570
 571 #else
 572
 573 #error host CPU specific signal handler needed
 574
 575 #endif