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 "config.h"
  20 #include "cpu.h"
  21 #include "dyngen-exec.h"
  22 #include "disas.h"
  23 #include "tcg.h"
  24
  25 #undef EAX
  26 #undef ECX
  27 #undef EDX
  28 #undef EBX
  29 #undef ESP
  30 #undef EBP
  31 #undef ESI
  32 #undef EDI
  33 #undef EIP
  34 #include <signal.h>
  35 #ifdef __linux__
  36 #include <sys/ucontext.h>
  37 #endif
  38
  39 //#define DEBUG_SIGNAL
  40
  41 static void exception_action(CPUArchState *env1)
  42 {
  43 #if defined(TARGET_I386)
  44     raise_exception_err_env(env1, env1->exception_index, env1->error_code);
  45 #else
  46     cpu_loop_exit(env1);
  47 #endif
  48 }
  49
  50 /* exit the current TB from a signal handler. The host registers are
  51    restored in a state compatible with the CPU emulator
  52  */
  53 void cpu_resume_from_signal(CPUArchState *env1, void *puc)
  54 {
  55 #ifdef __linux__
  56     struct ucontext *uc = puc;
  57 #elif defined(__OpenBSD__)
  58     struct sigcontext *uc = puc;
  59 #endif
  60
  61     env = env1;
  62
  63     /* XXX: restore cpu registers saved in host registers */
  64
  65     if (puc) {
  66         /* XXX: use siglongjmp ? */
  67 #ifdef __linux__
  68 #ifdef __ia64
  69         sigprocmask(SIG_SETMASK, (sigset_t *)&uc->uc_sigmask, NULL);
  70 #else
  71         sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL);
  72 #endif
  73 #elif defined(__OpenBSD__)
  74         sigprocmask(SIG_SETMASK, &uc->sc_mask, NULL);
  75 #endif
  76     }
  77     env->exception_index = -1;
  78     longjmp(env->jmp_env, 1);
  79 }
  80
  81 /* 'pc' is the host PC at which the exception was raised. 'address' is
  82    the effective address of the memory exception. 'is_write' is 1 if a
  83    write caused the exception and otherwise 0'. 'old_set' is the
  84    signal set which should be restored */
  85 static inline int handle_cpu_signal(uintptr_t pc, unsigned long address,
  86                                     int is_write, sigset_t *old_set,
  87                                     void *puc)
  88 {
  89     TranslationBlock *tb;
  90     int ret;
  91
  92     if (cpu_single_env) {
  93         env = cpu_single_env; /* XXX: find a correct solution for multithread */
  94     }
  95 #if defined(DEBUG_SIGNAL)
  96     qemu_printf("qemu: SIGSEGV pc=0x%08lx address=%08lx w=%d oldset=0x%08lx\n",
  97                 pc, address, is_write, *(unsigned long *)old_set);
  98 #endif
  99     /* XXX: locking issue */
 100     if (is_write && h2g_valid(address)
 101         && page_unprotect(h2g(address), pc, puc)) {
 102         return 1;
 103     }
 104
 105     /* see if it is an MMU fault */
 106     ret = cpu_handle_mmu_fault(env, address, is_write, MMU_USER_IDX);
 107     if (ret < 0) {
 108         return 0; /* not an MMU fault */
 109     }
 110     if (ret == 0) {
 111         return 1; /* the MMU fault was handled without causing real CPU fault */
 112     }
 113     /* now we have a real cpu fault */
 114     tb = tb_find_pc(pc);
 115     if (tb) {
 116         /* the PC is inside the translated code. It means that we have
 117            a virtual CPU fault */
 118         cpu_restore_state(tb, env, pc);
 119     }
 120
 121     /* we restore the process signal mask as the sigreturn should
 122        do it (XXX: use sigsetjmp) */
 123     sigprocmask(SIG_SETMASK, old_set, NULL);
 124     exception_action(env);
 125
 126     /* never comes here */
 127     return 1;
 128 }
 129
 130 #if defined(__i386__)
 131
 132 #if defined(__APPLE__)
 133 #include <sys/ucontext.h>
 134
 135 #define EIP_sig(context)  (*((unsigned long *)&(context)->uc_mcontext->ss.eip))
 136 #define TRAP_sig(context)    ((context)->uc_mcontext->es.trapno)
 137 #define ERROR_sig(context)   ((context)->uc_mcontext->es.err)
 138 #define MASK_sig(context)    ((context)->uc_sigmask)
 139 #elif defined(__NetBSD__)
 140 #include <ucontext.h>
 141
 142 #define EIP_sig(context)     ((context)->uc_mcontext.__gregs[_REG_EIP])
 143 #define TRAP_sig(context)    ((context)->uc_mcontext.__gregs[_REG_TRAPNO])
 144 #define ERROR_sig(context)   ((context)->uc_mcontext.__gregs[_REG_ERR])
 145 #define MASK_sig(context)    ((context)->uc_sigmask)
 146 #elif defined(__FreeBSD__) || defined(__DragonFly__)
 147 #include <ucontext.h>
 148
 149 #define EIP_sig(context)  (*((unsigned long *)&(context)->uc_mcontext.mc_eip))
 150 #define TRAP_sig(context)    ((context)->uc_mcontext.mc_trapno)
 151 #define ERROR_sig(context)   ((context)->uc_mcontext.mc_err)
 152 #define MASK_sig(context)    ((context)->uc_sigmask)
 153 #elif defined(__OpenBSD__)
 154 #define EIP_sig(context)     ((context)->sc_eip)
 155 #define TRAP_sig(context)    ((context)->sc_trapno)
 156 #define ERROR_sig(context)   ((context)->sc_err)
 157 #define MASK_sig(context)    ((context)->sc_mask)
 158 #else
 159 #define EIP_sig(context)     ((context)->uc_mcontext.gregs[REG_EIP])
 160 #define TRAP_sig(context)    ((context)->uc_mcontext.gregs[REG_TRAPNO])
 161 #define ERROR_sig(context)   ((context)->uc_mcontext.gregs[REG_ERR])
 162 #define MASK_sig(context)    ((context)->uc_sigmask)
 163 #endif
 164
 165 int cpu_signal_handler(int host_signum, void *pinfo,
 166                        void *puc)
 167 {
 168     siginfo_t *info = pinfo;
 169 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
 170     ucontext_t *uc = puc;
 171 #elif defined(__OpenBSD__)
 172     struct sigcontext *uc = puc;
 173 #else
 174     struct ucontext *uc = puc;
 175 #endif
 176     unsigned long pc;
 177     int trapno;
 178
 179 #ifndef REG_EIP
 180 /* for glibc 2.1 */
 181 #define REG_EIP    EIP
 182 #define REG_ERR    ERR
 183 #define REG_TRAPNO TRAPNO
 184 #endif
 185     pc = EIP_sig(uc);
 186     trapno = TRAP_sig(uc);
 187     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 188                              trapno == 0xe ?
 189                              (ERROR_sig(uc) >> 1) & 1 : 0,
 190                              &MASK_sig(uc), puc);
 191 }
 192
 193 #elif defined(__x86_64__)
 194
 195 #ifdef __NetBSD__
 196 #define PC_sig(context)       _UC_MACHINE_PC(context)
 197 #define TRAP_sig(context)     ((context)->uc_mcontext.__gregs[_REG_TRAPNO])
 198 #define ERROR_sig(context)    ((context)->uc_mcontext.__gregs[_REG_ERR])
 199 #define MASK_sig(context)     ((context)->uc_sigmask)
 200 #elif defined(__OpenBSD__)
 201 #define PC_sig(context)       ((context)->sc_rip)
 202 #define TRAP_sig(context)     ((context)->sc_trapno)
 203 #define ERROR_sig(context)    ((context)->sc_err)
 204 #define MASK_sig(context)     ((context)->sc_mask)
 205 #elif defined(__FreeBSD__) || defined(__DragonFly__)
 206 #include <ucontext.h>
 207
 208 #define PC_sig(context)  (*((unsigned long *)&(context)->uc_mcontext.mc_rip))
 209 #define TRAP_sig(context)     ((context)->uc_mcontext.mc_trapno)
 210 #define ERROR_sig(context)    ((context)->uc_mcontext.mc_err)
 211 #define MASK_sig(context)     ((context)->uc_sigmask)
 212 #else
 213 #define PC_sig(context)       ((context)->uc_mcontext.gregs[REG_RIP])
 214 #define TRAP_sig(context)     ((context)->uc_mcontext.gregs[REG_TRAPNO])
 215 #define ERROR_sig(context)    ((context)->uc_mcontext.gregs[REG_ERR])
 216 #define MASK_sig(context)     ((context)->uc_sigmask)
 217 #endif
 218
 219 int cpu_signal_handler(int host_signum, void *pinfo,
 220                        void *puc)
 221 {
 222     siginfo_t *info = pinfo;
 223     unsigned long pc;
 224 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
 225     ucontext_t *uc = puc;
 226 #elif defined(__OpenBSD__)
 227     struct sigcontext *uc = puc;
 228 #else
 229     struct ucontext *uc = puc;
 230 #endif
 231
 232     pc = PC_sig(uc);
 233     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 234                              TRAP_sig(uc) == 0xe ?
 235                              (ERROR_sig(uc) >> 1) & 1 : 0,
 236                              &MASK_sig(uc), puc);
 237 }
 238
 239 #elif defined(_ARCH_PPC)
 240
 241 /***********************************************************************
 242  * signal context platform-specific definitions
 243  * From Wine
 244  */
 245 #ifdef linux
 246 /* All Registers access - only for local access */
 247 #define REG_sig(reg_name, context)              \
 248     ((context)->uc_mcontext.regs->reg_name)
 249 /* Gpr Registers access  */
 250 #define GPR_sig(reg_num, context)              REG_sig(gpr[reg_num], context)
 251 /* Program counter */
 252 #define IAR_sig(context)                       REG_sig(nip, context)
 253 /* Machine State Register (Supervisor) */
 254 #define MSR_sig(context)                       REG_sig(msr, context)
 255 /* Count register */
 256 #define CTR_sig(context)                       REG_sig(ctr, context)
 257 /* User's integer exception register */
 258 #define XER_sig(context)                       REG_sig(xer, context)
 259 /* Link register */
 260 #define LR_sig(context)                        REG_sig(link, context)
 261 /* Condition register */
 262 #define CR_sig(context)                        REG_sig(ccr, context)
 263
 264 /* Float Registers access  */
 265 #define FLOAT_sig(reg_num, context)                                     \
 266     (((double *)((char *)((context)->uc_mcontext.regs + 48 * 4)))[reg_num])
 267 #define FPSCR_sig(context) \
 268     (*(int *)((char *)((context)->uc_mcontext.regs + (48 + 32 * 2) * 4)))
 269 /* Exception Registers access */
 270 #define DAR_sig(context)                       REG_sig(dar, context)
 271 #define DSISR_sig(context)                     REG_sig(dsisr, context)
 272 #define TRAP_sig(context)                      REG_sig(trap, context)
 273 #endif /* linux */
 274
 275 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
 276 #include <ucontext.h>
 277 #define IAR_sig(context)               ((context)->uc_mcontext.mc_srr0)
 278 #define MSR_sig(context)               ((context)->uc_mcontext.mc_srr1)
 279 #define CTR_sig(context)               ((context)->uc_mcontext.mc_ctr)
 280 #define XER_sig(context)               ((context)->uc_mcontext.mc_xer)
 281 #define LR_sig(context)                ((context)->uc_mcontext.mc_lr)
 282 #define CR_sig(context)                ((context)->uc_mcontext.mc_cr)
 283 /* Exception Registers access */
 284 #define DAR_sig(context)               ((context)->uc_mcontext.mc_dar)
 285 #define DSISR_sig(context)             ((context)->uc_mcontext.mc_dsisr)
 286 #define TRAP_sig(context)              ((context)->uc_mcontext.mc_exc)
 287 #endif /* __FreeBSD__|| __FreeBSD_kernel__ */
 288
 289 #ifdef __APPLE__
 290 #include <sys/ucontext.h>
 291 typedef struct ucontext SIGCONTEXT;
 292 /* All Registers access - only for local access */
 293 #define REG_sig(reg_name, context)              \
 294     ((context)->uc_mcontext->ss.reg_name)
 295 #define FLOATREG_sig(reg_name, context)         \
 296     ((context)->uc_mcontext->fs.reg_name)
 297 #define EXCEPREG_sig(reg_name, context)         \
 298     ((context)->uc_mcontext->es.reg_name)
 299 #define VECREG_sig(reg_name, context)           \
 300     ((context)->uc_mcontext->vs.reg_name)
 301 /* Gpr Registers access */
 302 #define GPR_sig(reg_num, context)              REG_sig(r##reg_num, context)
 303 /* Program counter */
 304 #define IAR_sig(context)                       REG_sig(srr0, context)
 305 /* Machine State Register (Supervisor) */
 306 #define MSR_sig(context)                       REG_sig(srr1, context)
 307 #define CTR_sig(context)                       REG_sig(ctr, context)
 308 /* Link register */
 309 #define XER_sig(context)                       REG_sig(xer, context)
 310 /* User's integer exception register */
 311 #define LR_sig(context)                        REG_sig(lr, context)
 312 /* Condition register */
 313 #define CR_sig(context)                        REG_sig(cr, context)
 314 /* Float Registers access */
 315 #define FLOAT_sig(reg_num, context)             \
 316     FLOATREG_sig(fpregs[reg_num], context)
 317 #define FPSCR_sig(context)                      \
 318     ((double)FLOATREG_sig(fpscr, context))
 319 /* Exception Registers access */
 320 /* Fault registers for coredump */
 321 #define DAR_sig(context)                       EXCEPREG_sig(dar, context)
 322 #define DSISR_sig(context)                     EXCEPREG_sig(dsisr, context)
 323 /* number of powerpc exception taken */
 324 #define TRAP_sig(context)                      EXCEPREG_sig(exception, context)
 325 #endif /* __APPLE__ */
 326
 327 int cpu_signal_handler(int host_signum, void *pinfo,
 328                        void *puc)
 329 {
 330     siginfo_t *info = pinfo;
 331 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
 332     ucontext_t *uc = puc;
 333 #else
 334     struct ucontext *uc = puc;
 335 #endif
 336     unsigned long pc;
 337     int is_write;
 338
 339     pc = IAR_sig(uc);
 340     is_write = 0;
 341 #if 0
 342     /* ppc 4xx case */
 343     if (DSISR_sig(uc) & 0x00800000) {
 344         is_write = 1;
 345     }
 346 #else
 347     if (TRAP_sig(uc) != 0x400 && (DSISR_sig(uc) & 0x02000000)) {
 348         is_write = 1;
 349     }
 350 #endif
 351     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 352                              is_write, &uc->uc_sigmask, puc);
 353 }
 354
 355 #elif defined(__alpha__)
 356
 357 int cpu_signal_handler(int host_signum, void *pinfo,
 358                            void *puc)
 359 {
 360     siginfo_t *info = pinfo;
 361     struct ucontext *uc = puc;
 362     uint32_t *pc = uc->uc_mcontext.sc_pc;
 363     uint32_t insn = *pc;
 364     int is_write = 0;
 365
 366     /* XXX: need kernel patch to get write flag faster */
 367     switch (insn >> 26) {
 368     case 0x0d: /* stw */
 369     case 0x0e: /* stb */
 370     case 0x0f: /* stq_u */
 371     case 0x24: /* stf */
 372     case 0x25: /* stg */
 373     case 0x26: /* sts */
 374     case 0x27: /* stt */
 375     case 0x2c: /* stl */
 376     case 0x2d: /* stq */
 377     case 0x2e: /* stl_c */
 378     case 0x2f: /* stq_c */
 379         is_write = 1;
 380     }
 381
 382     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 383                              is_write, &uc->uc_sigmask, puc);
 384 }
 385 #elif defined(__sparc__)
 386
 387 int cpu_signal_handler(int host_signum, void *pinfo,
 388                        void *puc)
 389 {
 390     siginfo_t *info = pinfo;
 391     int is_write;
 392     uint32_t insn;
 393 #if !defined(__arch64__) || defined(CONFIG_SOLARIS)
 394     uint32_t *regs = (uint32_t *)(info + 1);
 395     void *sigmask = (regs + 20);
 396     /* XXX: is there a standard glibc define ? */
 397     unsigned long pc = regs[1];
 398 #else
 399 #ifdef __linux__
 400     struct sigcontext *sc = puc;
 401     unsigned long pc = sc->sigc_regs.tpc;
 402     void *sigmask = (void *)sc->sigc_mask;
 403 #elif defined(__OpenBSD__)
 404     struct sigcontext *uc = puc;
 405     unsigned long pc = uc->sc_pc;
 406     void *sigmask = (void *)(long)uc->sc_mask;
 407 #endif
 408 #endif
 409
 410     /* XXX: need kernel patch to get write flag faster */
 411     is_write = 0;
 412     insn = *(uint32_t *)pc;
 413     if ((insn >> 30) == 3) {
 414         switch ((insn >> 19) & 0x3f) {
 415         case 0x05: /* stb */
 416         case 0x15: /* stba */
 417         case 0x06: /* sth */
 418         case 0x16: /* stha */
 419         case 0x04: /* st */
 420         case 0x14: /* sta */
 421         case 0x07: /* std */
 422         case 0x17: /* stda */
 423         case 0x0e: /* stx */
 424         case 0x1e: /* stxa */
 425         case 0x24: /* stf */
 426         case 0x34: /* stfa */
 427         case 0x27: /* stdf */
 428         case 0x37: /* stdfa */
 429         case 0x26: /* stqf */
 430         case 0x36: /* stqfa */
 431         case 0x25: /* stfsr */
 432         case 0x3c: /* casa */
 433         case 0x3e: /* casxa */
 434             is_write = 1;
 435             break;
 436         }
 437     }
 438     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 439                              is_write, sigmask, NULL);
 440 }
 441
 442 #elif defined(__arm__)
 443
 444 int cpu_signal_handler(int host_signum, void *pinfo,
 445                        void *puc)
 446 {
 447     siginfo_t *info = pinfo;
 448     struct ucontext *uc = puc;
 449     unsigned long pc;
 450     int is_write;
 451
 452 #if (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
 453     pc = uc->uc_mcontext.gregs[R15];
 454 #else
 455     pc = uc->uc_mcontext.arm_pc;
 456 #endif
 457     /* XXX: compute is_write */
 458     is_write = 0;
 459     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 460                              is_write,
 461                              &uc->uc_sigmask, puc);
 462 }
 463
 464 #elif defined(__mc68000)
 465
 466 int cpu_signal_handler(int host_signum, void *pinfo,
 467                        void *puc)
 468 {
 469     siginfo_t *info = pinfo;
 470     struct ucontext *uc = puc;
 471     unsigned long pc;
 472     int is_write;
 473
 474     pc = uc->uc_mcontext.gregs[16];
 475     /* XXX: compute is_write */
 476     is_write = 0;
 477     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 478                              is_write,
 479                              &uc->uc_sigmask, puc);
 480 }
 481
 482 #elif defined(__ia64)
 483
 484 #ifndef __ISR_VALID
 485   /* This ought to be in <bits/siginfo.h>... */
 486 # define __ISR_VALID    1
 487 #endif
 488
 489 int cpu_signal_handler(int host_signum, void *pinfo, void *puc)
 490 {
 491     siginfo_t *info = pinfo;
 492     struct ucontext *uc = puc;
 493     unsigned long ip;
 494     int is_write = 0;
 495
 496     ip = uc->uc_mcontext.sc_ip;
 497     switch (host_signum) {
 498     case SIGILL:
 499     case SIGFPE:
 500     case SIGSEGV:
 501     case SIGBUS:
 502     case SIGTRAP:
 503         if (info->si_code && (info->si_segvflags & __ISR_VALID)) {
 504             /* ISR.W (write-access) is bit 33:  */
 505             is_write = (info->si_isr >> 33) & 1;
 506         }
 507         break;
 508
 509     default:
 510         break;
 511     }
 512     return handle_cpu_signal(ip, (unsigned long)info->si_addr,
 513                              is_write,
 514                              (sigset_t *)&uc->uc_sigmask, puc);
 515 }
 516
 517 #elif defined(__s390__)
 518
 519 int cpu_signal_handler(int host_signum, void *pinfo,
 520                        void *puc)
 521 {
 522     siginfo_t *info = pinfo;
 523     struct ucontext *uc = puc;
 524     unsigned long pc;
 525     uint16_t *pinsn;
 526     int is_write = 0;
 527
 528     pc = uc->uc_mcontext.psw.addr;
 529
 530     /* ??? On linux, the non-rt signal handler has 4 (!) arguments instead
 531        of the normal 2 arguments.  The 3rd argument contains the "int_code"
 532        from the hardware which does in fact contain the is_write value.
 533        The rt signal handler, as far as I can tell, does not give this value
 534        at all.  Not that we could get to it from here even if it were.  */
 535     /* ??? This is not even close to complete, since it ignores all
 536        of the read-modify-write instructions.  */
 537     pinsn = (uint16_t *)pc;
 538     switch (pinsn[0] >> 8) {
 539     case 0x50: /* ST */
 540     case 0x42: /* STC */
 541     case 0x40: /* STH */
 542         is_write = 1;
 543         break;
 544     case 0xc4: /* RIL format insns */
 545         switch (pinsn[0] & 0xf) {
 546         case 0xf: /* STRL */
 547         case 0xb: /* STGRL */
 548         case 0x7: /* STHRL */
 549             is_write = 1;
 550         }
 551         break;
 552     case 0xe3: /* RXY format insns */
 553         switch (pinsn[2] & 0xff) {
 554         case 0x50: /* STY */
 555         case 0x24: /* STG */
 556         case 0x72: /* STCY */
 557         case 0x70: /* STHY */
 558         case 0x8e: /* STPQ */
 559         case 0x3f: /* STRVH */
 560         case 0x3e: /* STRV */
 561         case 0x2f: /* STRVG */
 562             is_write = 1;
 563         }
 564         break;
 565     }
 566     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 567                              is_write, &uc->uc_sigmask, puc);
 568 }
 569
 570 #elif defined(__mips__)
 571
 572 int cpu_signal_handler(int host_signum, void *pinfo,
 573                        void *puc)
 574 {
 575     siginfo_t *info = pinfo;
 576     struct ucontext *uc = puc;
 577     greg_t pc = uc->uc_mcontext.pc;
 578     int is_write;
 579
 580     /* XXX: compute is_write */
 581     is_write = 0;
 582     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 583                              is_write, &uc->uc_sigmask, puc);
 584 }
 585
 586 #elif defined(__hppa__)
 587
 588 int cpu_signal_handler(int host_signum, void *pinfo,
 589                        void *puc)
 590 {
 591     struct siginfo *info = pinfo;
 592     struct ucontext *uc = puc;
 593     unsigned long pc = uc->uc_mcontext.sc_iaoq[0];
 594     uint32_t insn = *(uint32_t *)pc;
 595     int is_write = 0;
 596
 597     /* XXX: need kernel patch to get write flag faster.  */
 598     switch (insn >> 26) {
 599     case 0x1a: /* STW */
 600     case 0x19: /* STH */
 601     case 0x18: /* STB */
 602     case 0x1b: /* STWM */
 603         is_write = 1;
 604         break;
 605
 606     case 0x09: /* CSTWX, FSTWX, FSTWS */
 607     case 0x0b: /* CSTDX, FSTDX, FSTDS */
 608         /* Distinguish from coprocessor load ... */
 609         is_write = (insn >> 9) & 1;
 610         break;
 611
 612     case 0x03:
 613         switch ((insn >> 6) & 15) {
 614         case 0xa: /* STWS */
 615         case 0x9: /* STHS */
 616         case 0x8: /* STBS */
 617         case 0xe: /* STWAS */
 618         case 0xc: /* STBYS */
 619             is_write = 1;
 620         }
 621         break;
 622     }
 623
 624     return handle_cpu_signal(pc, (unsigned long)info->si_addr,
 625                              is_write, &uc->uc_sigmask, puc);
 626 }
 627
 628 #else
 629
 630 #error host CPU specific signal handler needed
 631
 632 #endif