1 /*
   2  * Copyright (c) 1999, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 // no precompiled headers
  26 #include "asm/macroAssembler.hpp"
  27 #include "classfile/classLoader.hpp"
  28 #include "classfile/systemDictionary.hpp"
  29 #include "classfile/vmSymbols.hpp"
  30 #include "code/icBuffer.hpp"
  31 #include "code/vtableStubs.hpp"
  32 #include "interpreter/interpreter.hpp"
  33 #include "jvm_solaris.h"
  34 #include "memory/allocation.inline.hpp"
  35 #include "mutex_solaris.inline.hpp"
  36 #include "os_share_solaris.hpp"
  37 #include "prims/jniFastGetField.hpp"
  38 #include "prims/jvm.h"
  39 #include "prims/jvm_misc.hpp"
  40 #include "runtime/arguments.hpp"
  41 #include "runtime/extendedPC.hpp"
  42 #include "runtime/frame.inline.hpp"
  43 #include "runtime/interfaceSupport.hpp"
  44 #include "runtime/java.hpp"
  45 #include "runtime/javaCalls.hpp"
  46 #include "runtime/mutexLocker.hpp"
  47 #include "runtime/osThread.hpp"
  48 #include "runtime/sharedRuntime.hpp"
  49 #include "runtime/stubRoutines.hpp"
  50 #include "runtime/thread.inline.hpp"
  51 #include "runtime/timer.hpp"
  52 #include "utilities/events.hpp"
  53 #include "utilities/vmError.hpp"
  54 
  55 // put OS-includes here
  56 # include <sys/types.h>
  57 # include <sys/mman.h>
  58 # include <pthread.h>
  59 # include <signal.h>
  60 # include <setjmp.h>
  61 # include <errno.h>
  62 # include <dlfcn.h>
  63 # include <stdio.h>
  64 # include <unistd.h>
  65 # include <sys/resource.h>
  66 # include <thread.h>
  67 # include <sys/stat.h>
  68 # include <sys/time.h>
  69 # include <sys/filio.h>
  70 # include <sys/utsname.h>
  71 # include <sys/systeminfo.h>
  72 # include <sys/socket.h>
  73 # include <sys/trap.h>
  74 # include <sys/lwp.h>
  75 # include <pwd.h>
  76 # include <poll.h>
  77 # include <sys/lwp.h>
  78 # include <procfs.h>     //  see comment in <sys/procfs.h>
  79 
  80 #ifndef AMD64
  81 // QQQ seems useless at this point
  82 # define _STRUCTURED_PROC 1  //  this gets us the new structured proc interfaces of 5.6 & later
  83 #endif // AMD64
  84 # include <sys/procfs.h>     //  see comment in <sys/procfs.h>
  85 
  86 
  87 #define MAX_PATH (2 * K)
  88 
  89 // Minimum stack size for the VM.  It's easier to document a constant value
  90 // but it's different for x86 and sparc because the page sizes are different.
  91 #ifdef AMD64
  92 size_t os::Solaris::min_stack_allowed = 224*K;
  93 #define REG_SP REG_RSP
  94 #define REG_PC REG_RIP
  95 #define REG_FP REG_RBP
  96 #else
  97 size_t os::Solaris::min_stack_allowed = 64*K;
  98 #define REG_SP UESP
  99 #define REG_PC EIP
 100 #define REG_FP EBP
 101 // 4900493 counter to prevent runaway LDTR refresh attempt
 102 
 103 static volatile int ldtr_refresh = 0;
 104 // the libthread instruction that faults because of the stale LDTR
 105 
 106 static const unsigned char movlfs[] = { 0x8e, 0xe0    // movl %eax,%fs
 107                        };
 108 #endif // AMD64
 109 
 110 char* os::non_memory_address_word() {
 111   // Must never look like an address returned by reserve_memory,
 112   // even in its subfields (as defined by the CPU immediate fields,
 113   // if the CPU splits constants across multiple instructions).
 114   return (char*) -1;
 115 }
 116 
 117 //
 118 // Validate a ucontext retrieved from walking a uc_link of a ucontext.
 119 // There are issues with libthread giving out uc_links for different threads
 120 // on the same uc_link chain and bad or circular links.
 121 //
 122 bool os::Solaris::valid_ucontext(Thread* thread, ucontext_t* valid, ucontext_t* suspect) {
 123   if (valid >= suspect ||
 124       valid->uc_stack.ss_flags != suspect->uc_stack.ss_flags ||
 125       valid->uc_stack.ss_sp    != suspect->uc_stack.ss_sp    ||
 126       valid->uc_stack.ss_size  != suspect->uc_stack.ss_size) {
 127     DEBUG_ONLY(tty->print_cr("valid_ucontext: failed test 1");)
 128     return false;
 129   }
 130 
 131   if (thread->is_Java_thread()) {
 132     if (!valid_stack_address(thread, (address)suspect)) {
 133       DEBUG_ONLY(tty->print_cr("valid_ucontext: uc_link not in thread stack");)
 134       return false;
 135     }
 136     if (!valid_stack_address(thread,  (address) suspect->uc_mcontext.gregs[REG_SP])) {
 137       DEBUG_ONLY(tty->print_cr("valid_ucontext: stackpointer not in thread stack");)
 138       return false;
 139     }
 140   }
 141   return true;
 142 }
 143 
 144 // We will only follow one level of uc_link since there are libthread
 145 // issues with ucontext linking and it is better to be safe and just
 146 // let caller retry later.
 147 ucontext_t* os::Solaris::get_valid_uc_in_signal_handler(Thread *thread,
 148   ucontext_t *uc) {
 149 
 150   ucontext_t *retuc = NULL;
 151 
 152   if (uc != NULL) {
 153     if (uc->uc_link == NULL) {
 154       // cannot validate without uc_link so accept current ucontext
 155       retuc = uc;
 156     } else if (os::Solaris::valid_ucontext(thread, uc, uc->uc_link)) {
 157       // first ucontext is valid so try the next one
 158       uc = uc->uc_link;
 159       if (uc->uc_link == NULL) {
 160         // cannot validate without uc_link so accept current ucontext
 161         retuc = uc;
 162       } else if (os::Solaris::valid_ucontext(thread, uc, uc->uc_link)) {
 163         // the ucontext one level down is also valid so return it
 164         retuc = uc;
 165       }
 166     }
 167   }
 168   return retuc;
 169 }
 170 
 171 // Assumes ucontext is valid
 172 ExtendedPC os::Solaris::ucontext_get_ExtendedPC(ucontext_t *uc) {
 173   return ExtendedPC((address)uc->uc_mcontext.gregs[REG_PC]);
 174 }
 175 
 176 // Assumes ucontext is valid
 177 intptr_t* os::Solaris::ucontext_get_sp(ucontext_t *uc) {
 178   return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
 179 }
 180 
 181 // Assumes ucontext is valid
 182 intptr_t* os::Solaris::ucontext_get_fp(ucontext_t *uc) {
 183   return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
 184 }
 185 
 186 address os::Solaris::ucontext_get_pc(ucontext_t *uc) {
 187   return (address) uc->uc_mcontext.gregs[REG_PC];
 188 }
 189 
 190 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
 191 // is currently interrupted by SIGPROF.
 192 //
 193 // The difference between this and os::fetch_frame_from_context() is that
 194 // here we try to skip nested signal frames.
 195 ExtendedPC os::Solaris::fetch_frame_from_ucontext(Thread* thread,
 196   ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
 197 
 198   assert(thread != NULL, "just checking");
 199   assert(ret_sp != NULL, "just checking");
 200   assert(ret_fp != NULL, "just checking");
 201 
 202   ucontext_t *luc = os::Solaris::get_valid_uc_in_signal_handler(thread, uc);
 203   return os::fetch_frame_from_context(luc, ret_sp, ret_fp);
 204 }
 205 
 206 ExtendedPC os::fetch_frame_from_context(void* ucVoid,
 207                     intptr_t** ret_sp, intptr_t** ret_fp) {
 208 
 209   ExtendedPC  epc;
 210   ucontext_t *uc = (ucontext_t*)ucVoid;
 211 
 212   if (uc != NULL) {
 213     epc = os::Solaris::ucontext_get_ExtendedPC(uc);
 214     if (ret_sp) *ret_sp = os::Solaris::ucontext_get_sp(uc);
 215     if (ret_fp) *ret_fp = os::Solaris::ucontext_get_fp(uc);
 216   } else {
 217     // construct empty ExtendedPC for return value checking
 218     epc = ExtendedPC(NULL);
 219     if (ret_sp) *ret_sp = (intptr_t *)NULL;
 220     if (ret_fp) *ret_fp = (intptr_t *)NULL;
 221   }
 222 
 223   return epc;
 224 }
 225 
 226 frame os::fetch_frame_from_context(void* ucVoid) {
 227   intptr_t* sp;
 228   intptr_t* fp;
 229   ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
 230   return frame(sp, fp, epc.pc());
 231 }
 232 
 233 frame os::get_sender_for_C_frame(frame* fr) {
 234   return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
 235 }
 236 
 237 extern "C" intptr_t *_get_current_sp();  // in .il file
 238 
 239 address os::current_stack_pointer() {
 240   return (address)_get_current_sp();
 241 }
 242 
 243 extern "C" intptr_t *_get_current_fp();  // in .il file
 244 
 245 frame os::current_frame() {
 246   intptr_t* fp = _get_current_fp();  // it's inlined so want current fp
 247   frame myframe((intptr_t*)os::current_stack_pointer(),
 248                 (intptr_t*)fp,
 249                 CAST_FROM_FN_PTR(address, os::current_frame));
 250   if (os::is_first_C_frame(&myframe)) {
 251     // stack is not walkable
 252     frame ret; // This will be a null useless frame
 253     return ret;
 254   } else {
 255     return os::get_sender_for_C_frame(&myframe);
 256   }
 257 }
 258 
 259 static int threadgetstate(thread_t tid, int *flags, lwpid_t *lwp, stack_t *ss, gregset_t rs, lwpstatus_t *lwpstatus) {
 260   char lwpstatusfile[PROCFILE_LENGTH];
 261   int lwpfd, err;
 262 
 263   if (err = os::Solaris::thr_getstate(tid, flags, lwp, ss, rs))
 264     return (err);
 265   if (*flags == TRS_LWPID) {
 266     sprintf(lwpstatusfile, "/proc/%d/lwp/%d/lwpstatus", getpid(),
 267             *lwp);
 268     if ((lwpfd = open(lwpstatusfile, O_RDONLY)) < 0) {
 269       perror("thr_mutator_status: open lwpstatus");
 270       return (EINVAL);
 271     }
 272     if (pread(lwpfd, lwpstatus, sizeof (lwpstatus_t), (off_t)0) !=
 273         sizeof (lwpstatus_t)) {
 274       perror("thr_mutator_status: read lwpstatus");
 275       (void) close(lwpfd);
 276       return (EINVAL);
 277     }
 278     (void) close(lwpfd);
 279   }
 280   return (0);
 281 }
 282 
 283 #ifndef AMD64
 284 
 285 // Detecting SSE support by OS
 286 // From solaris_i486.s
 287 extern "C" bool sse_check();
 288 extern "C" bool sse_unavailable();
 289 
 290 enum { SSE_UNKNOWN, SSE_NOT_SUPPORTED, SSE_SUPPORTED};
 291 static int sse_status = SSE_UNKNOWN;
 292 
 293 
 294 static void  check_for_sse_support() {
 295   if (!VM_Version::supports_sse()) {
 296     sse_status = SSE_NOT_SUPPORTED;
 297     return;
 298   }
 299   // looking for _sse_hw in libc.so, if it does not exist or
 300   // the value (int) is 0, OS has no support for SSE
 301   int *sse_hwp;
 302   void *h;
 303 
 304   if ((h=dlopen("/usr/lib/libc.so", RTLD_LAZY)) == NULL) {
 305     //open failed, presume no support for SSE
 306     sse_status = SSE_NOT_SUPPORTED;
 307     return;
 308   }
 309   if ((sse_hwp = (int *)dlsym(h, "_sse_hw")) == NULL) {
 310     sse_status = SSE_NOT_SUPPORTED;
 311   } else if (*sse_hwp == 0) {
 312     sse_status = SSE_NOT_SUPPORTED;
 313   }
 314   dlclose(h);
 315 
 316   if (sse_status == SSE_UNKNOWN) {
 317     bool (*try_sse)() = (bool (*)())sse_check;
 318     sse_status = (*try_sse)() ? SSE_SUPPORTED : SSE_NOT_SUPPORTED;
 319   }
 320 
 321 }
 322 
 323 #endif // AMD64
 324 
 325 bool os::supports_sse() {
 326 #ifdef AMD64
 327   return true;
 328 #else
 329   if (sse_status == SSE_UNKNOWN)
 330     check_for_sse_support();
 331   return sse_status == SSE_SUPPORTED;
 332 #endif // AMD64
 333 }
 334 
 335 bool os::is_allocatable(size_t bytes) {
 336 #ifdef AMD64
 337   return true;
 338 #else
 339 
 340   if (bytes < 2 * G) {
 341     return true;
 342   }
 343 
 344   char* addr = reserve_memory(bytes, NULL);
 345 
 346   if (addr != NULL) {
 347     release_memory(addr, bytes);
 348   }
 349 
 350   return addr != NULL;
 351 #endif // AMD64
 352 
 353 }
 354 
 355 extern "C" JNIEXPORT int
 356 JVM_handle_solaris_signal(int sig, siginfo_t* info, void* ucVoid,
 357                           int abort_if_unrecognized) {
 358   ucontext_t* uc = (ucontext_t*) ucVoid;
 359 
 360 #ifndef AMD64
 361   if (sig == SIGILL && info->si_addr == (caddr_t)sse_check) {
 362     // the SSE instruction faulted. supports_sse() need return false.
 363     uc->uc_mcontext.gregs[EIP] = (greg_t)sse_unavailable;
 364     return true;
 365   }
 366 #endif // !AMD64
 367 
 368   Thread* t = ThreadLocalStorage::get_thread_slow();  // slow & steady
 369 
 370   // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
 371   // (no destructors can be run)
 372   os::ThreadCrashProtection::check_crash_protection(sig, t);
 373 
 374   SignalHandlerMark shm(t);
 375 
 376   if(sig == SIGPIPE || sig == SIGXFSZ) {
 377     if (os::Solaris::chained_handler(sig, info, ucVoid)) {
 378       return true;
 379     } else {
 380       if (PrintMiscellaneous && (WizardMode || Verbose)) {
 381         char buf[64];
 382         warning("Ignoring %s - see 4229104 or 6499219",
 383                 os::exception_name(sig, buf, sizeof(buf)));
 384 
 385       }
 386       return true;
 387     }
 388   }
 389 
 390   JavaThread* thread = NULL;
 391   VMThread* vmthread = NULL;
 392 
 393   if (os::Solaris::signal_handlers_are_installed) {
 394     if (t != NULL ){
 395       if(t->is_Java_thread()) {
 396         thread = (JavaThread*)t;
 397       }
 398       else if(t->is_VM_thread()){
 399         vmthread = (VMThread *)t;
 400       }
 401     }
 402   }
 403 
 404   guarantee(sig != os::Solaris::SIGinterrupt(), "Can not chain VM interrupt signal, try -XX:+UseAltSigs");
 405 
 406   if (sig == os::Solaris::SIGasync()) {
 407     if(thread || vmthread){
 408       OSThread::SR_handler(t, uc);
 409       return true;
 410     } else if (os::Solaris::chained_handler(sig, info, ucVoid)) {
 411       return true;
 412     } else {
 413       // If os::Solaris::SIGasync not chained, and this is a non-vm and
 414       // non-java thread
 415       return true;
 416     }
 417   }
 418 
 419   if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
 420     // can't decode this kind of signal
 421     info = NULL;
 422   } else {
 423     assert(sig == info->si_signo, "bad siginfo");
 424   }
 425 
 426   // decide if this trap can be handled by a stub
 427   address stub = NULL;
 428 
 429   address pc          = NULL;
 430 
 431   //%note os_trap_1
 432   if (info != NULL && uc != NULL && thread != NULL) {
 433     // factor me: getPCfromContext
 434     pc = (address) uc->uc_mcontext.gregs[REG_PC];
 435 
 436     if (StubRoutines::is_safefetch_fault(pc)) {
 437       uc->uc_mcontext.gregs[REG_PC] = intptr_t(StubRoutines::continuation_for_safefetch_fault(pc));
 438       return true;
 439     }
 440 
 441     // Handle ALL stack overflow variations here
 442     if (sig == SIGSEGV && info->si_code == SEGV_ACCERR) {
 443       address addr = (address) info->si_addr;
 444       if (thread->in_stack_yellow_zone(addr)) {
 445         thread->disable_stack_yellow_zone();
 446         if (thread->thread_state() == _thread_in_Java) {
 447           // Throw a stack overflow exception.  Guard pages will be reenabled
 448           // while unwinding the stack.
 449           stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
 450         } else {
 451           // Thread was in the vm or native code.  Return and try to finish.
 452           return true;
 453         }
 454       } else if (thread->in_stack_red_zone(addr)) {
 455         // Fatal red zone violation.  Disable the guard pages and fall through
 456         // to handle_unexpected_exception way down below.
 457         thread->disable_stack_red_zone();
 458         tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
 459       }
 460     }
 461 
 462     if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) {
 463       // Verify that OS save/restore AVX registers.
 464       stub = VM_Version::cpuinfo_cont_addr();
 465     }
 466 
 467     if (thread->thread_state() == _thread_in_vm) {
 468       if (sig == SIGBUS && info->si_code == BUS_OBJERR && thread->doing_unsafe_access()) {
 469         stub = StubRoutines::handler_for_unsafe_access();
 470       }
 471     }
 472 
 473     if (thread->thread_state() == _thread_in_Java) {
 474       // Support Safepoint Polling
 475       if ( sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
 476         stub = SharedRuntime::get_poll_stub(pc);
 477       }
 478       else if (sig == SIGBUS && info->si_code == BUS_OBJERR) {
 479         // BugId 4454115: A read from a MappedByteBuffer can fault
 480         // here if the underlying file has been truncated.
 481         // Do not crash the VM in such a case.
 482         CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
 483         if (cb != NULL) {
 484           nmethod* nm = cb->is_nmethod() ? (nmethod*)cb : NULL;
 485           if (nm != NULL && nm->has_unsafe_access()) {
 486             stub = StubRoutines::handler_for_unsafe_access();
 487           }
 488         }
 489       }
 490       else
 491       if (sig == SIGFPE && info->si_code == FPE_INTDIV) {
 492         // integer divide by zero
 493         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
 494       }
 495 #ifndef AMD64
 496       else if (sig == SIGFPE && info->si_code == FPE_FLTDIV) {
 497         // floating-point divide by zero
 498         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
 499       }
 500       else if (sig == SIGFPE && info->si_code == FPE_FLTINV) {
 501         // The encoding of D2I in i486.ad can cause an exception prior
 502         // to the fist instruction if there was an invalid operation
 503         // pending. We want to dismiss that exception. From the win_32
 504         // side it also seems that if it really was the fist causing
 505         // the exception that we do the d2i by hand with different
 506         // rounding. Seems kind of weird. QQQ TODO
 507         // Note that we take the exception at the NEXT floating point instruction.
 508         if (pc[0] == 0xDB) {
 509             assert(pc[0] == 0xDB, "not a FIST opcode");
 510             assert(pc[1] == 0x14, "not a FIST opcode");
 511             assert(pc[2] == 0x24, "not a FIST opcode");
 512             return true;
 513         } else {
 514             assert(pc[-3] == 0xDB, "not an flt invalid opcode");
 515             assert(pc[-2] == 0x14, "not an flt invalid opcode");
 516             assert(pc[-1] == 0x24, "not an flt invalid opcode");
 517         }
 518       }
 519       else if (sig == SIGFPE ) {
 520         tty->print_cr("caught SIGFPE, info 0x%x.", info->si_code);
 521       }
 522 #endif // !AMD64
 523 
 524         // QQQ It doesn't seem that we need to do this on x86 because we should be able
 525         // to return properly from the handler without this extra stuff on the back side.
 526 
 527       else if (sig == SIGSEGV && info->si_code > 0 && !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
 528         // Determination of interpreter/vtable stub/compiled code null exception
 529         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
 530       }
 531     }
 532 
 533     // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
 534     // and the heap gets shrunk before the field access.
 535     if ((sig == SIGSEGV) || (sig == SIGBUS)) {
 536       address addr = JNI_FastGetField::find_slowcase_pc(pc);
 537       if (addr != (address)-1) {
 538         stub = addr;
 539       }
 540     }
 541 
 542     // Check to see if we caught the safepoint code in the
 543     // process of write protecting the memory serialization page.
 544     // It write enables the page immediately after protecting it
 545     // so we can just return to retry the write.
 546     if ((sig == SIGSEGV) &&
 547         os::is_memory_serialize_page(thread, (address)info->si_addr)) {
 548       // Block current thread until the memory serialize page permission restored.
 549       os::block_on_serialize_page_trap();
 550       return true;
 551     }
 552   }
 553 
 554   // Execution protection violation
 555   //
 556   // Preventative code for future versions of Solaris which may
 557   // enable execution protection when running the 32-bit VM on AMD64.
 558   //
 559   // This should be kept as the last step in the triage.  We don't
 560   // have a dedicated trap number for a no-execute fault, so be
 561   // conservative and allow other handlers the first shot.
 562   //
 563   // Note: We don't test that info->si_code == SEGV_ACCERR here.
 564   // this si_code is so generic that it is almost meaningless; and
 565   // the si_code for this condition may change in the future.
 566   // Furthermore, a false-positive should be harmless.
 567   if (UnguardOnExecutionViolation > 0 &&
 568       (sig == SIGSEGV || sig == SIGBUS) &&
 569       uc->uc_mcontext.gregs[TRAPNO] == T_PGFLT) {  // page fault
 570     int page_size = os::vm_page_size();
 571     address addr = (address) info->si_addr;
 572     address pc = (address) uc->uc_mcontext.gregs[REG_PC];
 573     // Make sure the pc and the faulting address are sane.
 574     //
 575     // If an instruction spans a page boundary, and the page containing
 576     // the beginning of the instruction is executable but the following
 577     // page is not, the pc and the faulting address might be slightly
 578     // different - we still want to unguard the 2nd page in this case.
 579     //
 580     // 15 bytes seems to be a (very) safe value for max instruction size.
 581     bool pc_is_near_addr =
 582       (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
 583     bool instr_spans_page_boundary =
 584       (align_size_down((intptr_t) pc ^ (intptr_t) addr,
 585                        (intptr_t) page_size) > 0);
 586 
 587     if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
 588       static volatile address last_addr =
 589         (address) os::non_memory_address_word();
 590 
 591       // In conservative mode, don't unguard unless the address is in the VM
 592       if (addr != last_addr &&
 593           (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
 594 
 595         // Make memory rwx and retry
 596         address page_start =
 597           (address) align_size_down((intptr_t) addr, (intptr_t) page_size);
 598         bool res = os::protect_memory((char*) page_start, page_size,
 599                                       os::MEM_PROT_RWX);
 600 
 601         if (PrintMiscellaneous && Verbose) {
 602           char buf[256];
 603           jio_snprintf(buf, sizeof(buf), "Execution protection violation "
 604                        "at " INTPTR_FORMAT
 605                        ", unguarding " INTPTR_FORMAT ": %s, errno=%d", addr,
 606                        page_start, (res ? "success" : "failed"), errno);
 607           tty->print_raw_cr(buf);
 608         }
 609         stub = pc;
 610 
 611         // Set last_addr so if we fault again at the same address, we don't end
 612         // up in an endless loop.
 613         //
 614         // There are two potential complications here.  Two threads trapping at
 615         // the same address at the same time could cause one of the threads to
 616         // think it already unguarded, and abort the VM.  Likely very rare.
 617         //
 618         // The other race involves two threads alternately trapping at
 619         // different addresses and failing to unguard the page, resulting in
 620         // an endless loop.  This condition is probably even more unlikely than
 621         // the first.
 622         //
 623         // Although both cases could be avoided by using locks or thread local
 624         // last_addr, these solutions are unnecessary complication: this
 625         // handler is a best-effort safety net, not a complete solution.  It is
 626         // disabled by default and should only be used as a workaround in case
 627         // we missed any no-execute-unsafe VM code.
 628 
 629         last_addr = addr;
 630       }
 631     }
 632   }
 633 
 634   if (stub != NULL) {
 635     // save all thread context in case we need to restore it
 636 
 637     if (thread != NULL) thread->set_saved_exception_pc(pc);
 638     // 12/02/99: On Sparc it appears that the full context is also saved
 639     // but as yet, no one looks at or restores that saved context
 640     // factor me: setPC
 641     uc->uc_mcontext.gregs[REG_PC] = (greg_t)stub;
 642     return true;
 643   }
 644 
 645   // signal-chaining
 646   if (os::Solaris::chained_handler(sig, info, ucVoid)) {
 647     return true;
 648   }
 649 
 650 #ifndef AMD64
 651   // Workaround (bug 4900493) for Solaris kernel bug 4966651.
 652   // Handle an undefined selector caused by an attempt to assign
 653   // fs in libthread getipriptr(). With the current libthread design every 512
 654   // thread creations the LDT for a private thread data structure is extended
 655   // and thre is a hazard that and another thread attempting a thread creation
 656   // will use a stale LDTR that doesn't reflect the structure's growth,
 657   // causing a GP fault.
 658   // Enforce the probable limit of passes through here to guard against an
 659   // infinite loop if some other move to fs caused the GP fault. Note that
 660   // this loop counter is ultimately a heuristic as it is possible for
 661   // more than one thread to generate this fault at a time in an MP system.
 662   // In the case of the loop count being exceeded or if the poll fails
 663   // just fall through to a fatal error.
 664   // If there is some other source of T_GPFLT traps and the text at EIP is
 665   // unreadable this code will loop infinitely until the stack is exausted.
 666   // The key to diagnosis in this case is to look for the bottom signal handler
 667   // frame.
 668 
 669   if(! IgnoreLibthreadGPFault) {
 670     if (sig == SIGSEGV && uc->uc_mcontext.gregs[TRAPNO] == T_GPFLT) {
 671       const unsigned char *p =
 672                         (unsigned const char *) uc->uc_mcontext.gregs[EIP];
 673 
 674       // Expected instruction?
 675 
 676       if(p[0] == movlfs[0] && p[1] == movlfs[1]) {
 677 
 678         Atomic::inc(&ldtr_refresh);
 679 
 680         // Infinite loop?
 681 
 682         if(ldtr_refresh < ((2 << 16) / PAGESIZE)) {
 683 
 684           // No, force scheduling to get a fresh view of the LDTR
 685 
 686           if(poll(NULL, 0, 10) == 0) {
 687 
 688             // Retry the move
 689 
 690             return false;
 691           }
 692         }
 693       }
 694     }
 695   }
 696 #endif // !AMD64
 697 
 698   if (!abort_if_unrecognized) {
 699     // caller wants another chance, so give it to him
 700     return false;
 701   }
 702 
 703   if (!os::Solaris::libjsig_is_loaded) {
 704     struct sigaction oldAct;
 705     sigaction(sig, (struct sigaction *)0, &oldAct);
 706     if (oldAct.sa_sigaction != signalHandler) {
 707       void* sighand = oldAct.sa_sigaction ? CAST_FROM_FN_PTR(void*,  oldAct.sa_sigaction)
 708                                           : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
 709       warning("Unexpected Signal %d occurred under user-defined signal handler %#lx", sig, (long)sighand);
 710     }
 711   }
 712 
 713   if (pc == NULL && uc != NULL) {
 714     pc = (address) uc->uc_mcontext.gregs[REG_PC];
 715   }
 716 
 717   // unmask current signal
 718   sigset_t newset;
 719   sigemptyset(&newset);
 720   sigaddset(&newset, sig);
 721   sigprocmask(SIG_UNBLOCK, &newset, NULL);
 722 
 723   // Determine which sort of error to throw.  Out of swap may signal
 724   // on the thread stack, which could get a mapping error when touched.
 725   address addr = (address) info->si_addr;
 726   if (sig == SIGBUS && info->si_code == BUS_OBJERR && info->si_errno == ENOMEM) {
 727     vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "Out of swap space to map in thread stack.");
 728   }
 729 
 730   VMError err(t, sig, pc, info, ucVoid);
 731   err.report_and_die();
 732 
 733   ShouldNotReachHere();
 734   return false;
 735 }
 736 
 737 void os::print_context(outputStream *st, void *context) {
 738   if (context == NULL) return;
 739 
 740   ucontext_t *uc = (ucontext_t*)context;
 741   st->print_cr("Registers:");
 742 #ifdef AMD64
 743   st->print(  "RAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RAX]);
 744   st->print(", RBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBX]);
 745   st->print(", RCX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RCX]);
 746   st->print(", RDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDX]);
 747   st->cr();
 748   st->print(  "RSP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSP]);
 749   st->print(", RBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBP]);
 750   st->print(", RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]);
 751   st->print(", RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]);
 752   st->cr();
 753   st->print(  "R8 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
 754   st->print(", R9 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]);
 755   st->print(", R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]);
 756   st->print(", R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]);
 757   st->cr();
 758   st->print(  "R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
 759   st->print(", R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]);
 760   st->print(", R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]);
 761   st->print(", R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]);
 762   st->cr();
 763   st->print(  "RIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RIP]);
 764   st->print(", RFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RFL]);
 765 #else
 766   st->print(  "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EAX]);
 767   st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EBX]);
 768   st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[ECX]);
 769   st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EDX]);
 770   st->cr();
 771   st->print(  "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[UESP]);
 772   st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EBP]);
 773   st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[ESI]);
 774   st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EDI]);
 775   st->cr();
 776   st->print(  "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EIP]);
 777   st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EFL]);
 778 #endif // AMD64
 779   st->cr();
 780   st->cr();
 781 
 782   intptr_t *sp = (intptr_t *)os::Solaris::ucontext_get_sp(uc);
 783   st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", sp);
 784   print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t));
 785   st->cr();
 786 
 787   // Note: it may be unsafe to inspect memory near pc. For example, pc may
 788   // point to garbage if entry point in an nmethod is corrupted. Leave
 789   // this at the end, and hope for the best.
 790   ExtendedPC epc = os::Solaris::ucontext_get_ExtendedPC(uc);
 791   address pc = epc.pc();
 792   st->print_cr("Instructions: (pc=" PTR_FORMAT ")", pc);
 793   print_hex_dump(st, pc - 32, pc + 32, sizeof(char));
 794 }
 795 
 796 void os::print_register_info(outputStream *st, void *context) {
 797   if (context == NULL) return;
 798 
 799   ucontext_t *uc = (ucontext_t*)context;
 800 
 801   st->print_cr("Register to memory mapping:");
 802   st->cr();
 803 
 804   // this is horrendously verbose but the layout of the registers in the
 805   // context does not match how we defined our abstract Register set, so
 806   // we can't just iterate through the gregs area
 807 
 808   // this is only for the "general purpose" registers
 809 
 810 #ifdef AMD64
 811   st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
 812   st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
 813   st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
 814   st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
 815   st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
 816   st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
 817   st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
 818   st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
 819   st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
 820   st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
 821   st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
 822   st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
 823   st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
 824   st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
 825   st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
 826   st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
 827 #else
 828   st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[EAX]);
 829   st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[EBX]);
 830   st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[ECX]);
 831   st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[EDX]);
 832   st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[UESP]);
 833   st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[EBP]);
 834   st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[ESI]);
 835   st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[EDI]);
 836 #endif
 837 
 838   st->cr();
 839 }
 840 
 841 
 842 #ifdef AMD64
 843 void os::Solaris::init_thread_fpu_state(void) {
 844   // Nothing to do
 845 }
 846 #else
 847 // From solaris_i486.s
 848 extern "C" void fixcw();
 849 
 850 void os::Solaris::init_thread_fpu_state(void) {
 851   // Set fpu to 53 bit precision. This happens too early to use a stub.
 852   fixcw();
 853 }
 854 
 855 // These routines are the initial value of atomic_xchg_entry(),
 856 // atomic_cmpxchg_entry(), atomic_inc_entry() and fence_entry()
 857 // until initialization is complete.
 858 // TODO - replace with .il implementation when compiler supports it.
 859 
 860 typedef jint  xchg_func_t        (jint,  volatile jint*);
 861 typedef jint  cmpxchg_func_t     (jint,  volatile jint*,  jint);
 862 typedef jlong cmpxchg_long_func_t(jlong, volatile jlong*, jlong);
 863 typedef jint  add_func_t         (jint,  volatile jint*);
 864 
 865 jint os::atomic_xchg_bootstrap(jint exchange_value, volatile jint* dest) {
 866   // try to use the stub:
 867   xchg_func_t* func = CAST_TO_FN_PTR(xchg_func_t*, StubRoutines::atomic_xchg_entry());
 868 
 869   if (func != NULL) {
 870     os::atomic_xchg_func = func;
 871     return (*func)(exchange_value, dest);
 872   }
 873   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 874 
 875   jint old_value = *dest;
 876   *dest = exchange_value;
 877   return old_value;
 878 }
 879 
 880 jint os::atomic_cmpxchg_bootstrap(jint exchange_value, volatile jint* dest, jint compare_value) {
 881   // try to use the stub:
 882   cmpxchg_func_t* func = CAST_TO_FN_PTR(cmpxchg_func_t*, StubRoutines::atomic_cmpxchg_entry());
 883 
 884   if (func != NULL) {
 885     os::atomic_cmpxchg_func = func;
 886     return (*func)(exchange_value, dest, compare_value);
 887   }
 888   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 889 
 890   jint old_value = *dest;
 891   if (old_value == compare_value)
 892     *dest = exchange_value;
 893   return old_value;
 894 }
 895 
 896 jlong os::atomic_cmpxchg_long_bootstrap(jlong exchange_value, volatile jlong* dest, jlong compare_value) {
 897   // try to use the stub:
 898   cmpxchg_long_func_t* func = CAST_TO_FN_PTR(cmpxchg_long_func_t*, StubRoutines::atomic_cmpxchg_long_entry());
 899 
 900   if (func != NULL) {
 901     os::atomic_cmpxchg_long_func = func;
 902     return (*func)(exchange_value, dest, compare_value);
 903   }
 904   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 905 
 906   jlong old_value = *dest;
 907   if (old_value == compare_value)
 908     *dest = exchange_value;
 909   return old_value;
 910 }
 911 
 912 jint os::atomic_add_bootstrap(jint add_value, volatile jint* dest) {
 913   // try to use the stub:
 914   add_func_t* func = CAST_TO_FN_PTR(add_func_t*, StubRoutines::atomic_add_entry());
 915 
 916   if (func != NULL) {
 917     os::atomic_add_func = func;
 918     return (*func)(add_value, dest);
 919   }
 920   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 921 
 922   return (*dest) += add_value;
 923 }
 924 
 925 xchg_func_t*         os::atomic_xchg_func         = os::atomic_xchg_bootstrap;
 926 cmpxchg_func_t*      os::atomic_cmpxchg_func      = os::atomic_cmpxchg_bootstrap;
 927 cmpxchg_long_func_t* os::atomic_cmpxchg_long_func = os::atomic_cmpxchg_long_bootstrap;
 928 add_func_t*          os::atomic_add_func          = os::atomic_add_bootstrap;
 929 
 930 extern "C" void _solaris_raw_setup_fpu(address ptr);
 931 void os::setup_fpu() {
 932   address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
 933   _solaris_raw_setup_fpu(fpu_cntrl);
 934 }
 935 #endif // AMD64
 936 
 937 #ifndef PRODUCT
 938 void os::verify_stack_alignment() {
 939 #ifdef AMD64
 940   assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
 941 #endif
 942 }
 943 #endif