1 /*
   2  * Copyright (c) 1999, 2011, 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 "assembler_x86.inline.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 "nativeInst_x86.hpp"
  37 #include "os_share_solaris.hpp"
  38 #include "prims/jniFastGetField.hpp"
  39 #include "prims/jvm.h"
  40 #include "prims/jvm_misc.hpp"
  41 #include "runtime/arguments.hpp"
  42 #include "runtime/extendedPC.hpp"
  43 #include "runtime/frame.inline.hpp"
  44 #include "runtime/interfaceSupport.hpp"
  45 #include "runtime/java.hpp"
  46 #include "runtime/javaCalls.hpp"
  47 #include "runtime/mutexLocker.hpp"
  48 #include "runtime/osThread.hpp"
  49 #include "runtime/sharedRuntime.hpp"
  50 #include "runtime/stubRoutines.hpp"
  51 #include "runtime/timer.hpp"
  52 #include "thread_solaris.inline.hpp"
  53 #include "utilities/events.hpp"
  54 #include "utilities/vmError.hpp"
  55 
  56 // put OS-includes here
  57 # include <sys/types.h>
  58 # include <sys/mman.h>
  59 # include <pthread.h>
  60 # include <signal.h>
  61 # include <setjmp.h>
  62 # include <errno.h>
  63 # include <dlfcn.h>
  64 # include <stdio.h>
  65 # include <unistd.h>
  66 # include <sys/resource.h>
  67 # include <thread.h>
  68 # include <sys/stat.h>
  69 # include <sys/time.h>
  70 # include <sys/filio.h>
  71 # include <sys/utsname.h>
  72 # include <sys/systeminfo.h>
  73 # include <sys/socket.h>
  74 # include <sys/trap.h>
  75 # include <sys/lwp.h>
  76 # include <pwd.h>
  77 # include <poll.h>
  78 # include <sys/lwp.h>
  79 # include <procfs.h>     //  see comment in <sys/procfs.h>
  80 
  81 #ifndef AMD64
  82 // QQQ seems useless at this point
  83 # define _STRUCTURED_PROC 1  //  this gets us the new structured proc interfaces of 5.6 & later
  84 #endif // AMD64
  85 # include <sys/procfs.h>     //  see comment in <sys/procfs.h>
  86 
  87 
  88 #define MAX_PATH (2 * K)
  89 
  90 // Minimum stack size for the VM.  It's easier to document a constant value
  91 // but it's different for x86 and sparc because the page sizes are different.
  92 #ifdef AMD64
  93 size_t os::Solaris::min_stack_allowed = 224*K;
  94 #define REG_SP REG_RSP
  95 #define REG_PC REG_RIP
  96 #define REG_FP REG_RBP
  97 #else
  98 size_t os::Solaris::min_stack_allowed = 64*K;
  99 #define REG_SP UESP
 100 #define REG_PC EIP
 101 #define REG_FP EBP
 102 // 4900493 counter to prevent runaway LDTR refresh attempt
 103 
 104 static volatile int ldtr_refresh = 0;
 105 // the libthread instruction that faults because of the stale LDTR
 106 
 107 static const unsigned char movlfs[] = { 0x8e, 0xe0    // movl %eax,%fs
 108                        };
 109 #endif // AMD64
 110 
 111 char* os::non_memory_address_word() {
 112   // Must never look like an address returned by reserve_memory,
 113   // even in its subfields (as defined by the CPU immediate fields,
 114   // if the CPU splits constants across multiple instructions).
 115   return (char*) -1;
 116 }
 117 
 118 //
 119 // Validate a ucontext retrieved from walking a uc_link of a ucontext.
 120 // There are issues with libthread giving out uc_links for different threads
 121 // on the same uc_link chain and bad or circular links.
 122 //
 123 bool os::Solaris::valid_ucontext(Thread* thread, ucontext_t* valid, ucontext_t* suspect) {
 124   if (valid >= suspect ||
 125       valid->uc_stack.ss_flags != suspect->uc_stack.ss_flags ||
 126       valid->uc_stack.ss_sp    != suspect->uc_stack.ss_sp    ||
 127       valid->uc_stack.ss_size  != suspect->uc_stack.ss_size) {
 128     DEBUG_ONLY(tty->print_cr("valid_ucontext: failed test 1");)
 129     return false;
 130   }
 131 
 132   if (thread->is_Java_thread()) {
 133     if (!valid_stack_address(thread, (address)suspect)) {
 134       DEBUG_ONLY(tty->print_cr("valid_ucontext: uc_link not in thread stack");)
 135       return false;
 136     }
 137     if (!valid_stack_address(thread,  (address) suspect->uc_mcontext.gregs[REG_SP])) {
 138       DEBUG_ONLY(tty->print_cr("valid_ucontext: stackpointer not in thread stack");)
 139       return false;
 140     }
 141   }
 142   return true;
 143 }
 144 
 145 // We will only follow one level of uc_link since there are libthread
 146 // issues with ucontext linking and it is better to be safe and just
 147 // let caller retry later.
 148 ucontext_t* os::Solaris::get_valid_uc_in_signal_handler(Thread *thread,
 149   ucontext_t *uc) {
 150 
 151   ucontext_t *retuc = NULL;
 152 
 153   if (uc != NULL) {
 154     if (uc->uc_link == NULL) {
 155       // cannot validate without uc_link so accept current ucontext
 156       retuc = uc;
 157     } else if (os::Solaris::valid_ucontext(thread, uc, uc->uc_link)) {
 158       // first ucontext is valid so try the next one
 159       uc = uc->uc_link;
 160       if (uc->uc_link == NULL) {
 161         // cannot validate without uc_link so accept current ucontext
 162         retuc = uc;
 163       } else if (os::Solaris::valid_ucontext(thread, uc, uc->uc_link)) {
 164         // the ucontext one level down is also valid so return it
 165         retuc = uc;
 166       }
 167     }
 168   }
 169   return retuc;
 170 }
 171 
 172 // Assumes ucontext is valid
 173 ExtendedPC os::Solaris::ucontext_get_ExtendedPC(ucontext_t *uc) {
 174   return ExtendedPC((address)uc->uc_mcontext.gregs[REG_PC]);
 175 }
 176 
 177 // Assumes ucontext is valid
 178 intptr_t* os::Solaris::ucontext_get_sp(ucontext_t *uc) {
 179   return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
 180 }
 181 
 182 // Assumes ucontext is valid
 183 intptr_t* os::Solaris::ucontext_get_fp(ucontext_t *uc) {
 184   return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
 185 }
 186 
 187 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
 188 // is currently interrupted by SIGPROF.
 189 //
 190 // The difference between this and os::fetch_frame_from_context() is that
 191 // here we try to skip nested signal frames.
 192 ExtendedPC os::Solaris::fetch_frame_from_ucontext(Thread* thread,
 193   ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
 194 
 195   assert(thread != NULL, "just checking");
 196   assert(ret_sp != NULL, "just checking");
 197   assert(ret_fp != NULL, "just checking");
 198 
 199   ucontext_t *luc = os::Solaris::get_valid_uc_in_signal_handler(thread, uc);
 200   return os::fetch_frame_from_context(luc, ret_sp, ret_fp);
 201 }
 202 
 203 ExtendedPC os::fetch_frame_from_context(void* ucVoid,
 204                     intptr_t** ret_sp, intptr_t** ret_fp) {
 205 
 206   ExtendedPC  epc;
 207   ucontext_t *uc = (ucontext_t*)ucVoid;
 208 
 209   if (uc != NULL) {
 210     epc = os::Solaris::ucontext_get_ExtendedPC(uc);
 211     if (ret_sp) *ret_sp = os::Solaris::ucontext_get_sp(uc);
 212     if (ret_fp) *ret_fp = os::Solaris::ucontext_get_fp(uc);
 213   } else {
 214     // construct empty ExtendedPC for return value checking
 215     epc = ExtendedPC(NULL);
 216     if (ret_sp) *ret_sp = (intptr_t *)NULL;
 217     if (ret_fp) *ret_fp = (intptr_t *)NULL;
 218   }
 219 
 220   return epc;
 221 }
 222 
 223 frame os::fetch_frame_from_context(void* ucVoid) {
 224   intptr_t* sp;
 225   intptr_t* fp;
 226   ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
 227   return frame(sp, fp, epc.pc());
 228 }
 229 
 230 frame os::get_sender_for_C_frame(frame* fr) {
 231   return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
 232 }
 233 
 234 extern "C" intptr_t *_get_current_sp();  // in .il file
 235 
 236 address os::current_stack_pointer() {
 237   return (address)_get_current_sp();
 238 }
 239 
 240 extern "C" intptr_t *_get_current_fp();  // in .il file
 241 
 242 frame os::current_frame() {
 243   intptr_t* fp = _get_current_fp();  // it's inlined so want current fp
 244   frame myframe((intptr_t*)os::current_stack_pointer(),
 245                 (intptr_t*)fp,
 246                 CAST_FROM_FN_PTR(address, os::current_frame));
 247   if (os::is_first_C_frame(&myframe)) {
 248     // stack is not walkable
 249     frame ret; // This will be a null useless frame
 250     return ret;
 251   } else {
 252     return os::get_sender_for_C_frame(&myframe);
 253   }
 254 }
 255 
 256 // This is a simple callback that just fetches a PC for an interrupted thread.
 257 // The thread need not be suspended and the fetched PC is just a hint.
 258 // This one is currently used for profiling the VMThread ONLY!
 259 
 260 // Must be synchronous
 261 void GetThreadPC_Callback::execute(OSThread::InterruptArguments *args) {
 262   Thread*     thread = args->thread();
 263   ucontext_t* uc     = args->ucontext();
 264   intptr_t* sp;
 265 
 266   assert(ProfileVM && thread->is_VM_thread(), "just checking");
 267 
 268   ExtendedPC new_addr((address)uc->uc_mcontext.gregs[REG_PC]);
 269   _addr = new_addr;
 270 }
 271 
 272 static int threadgetstate(thread_t tid, int *flags, lwpid_t *lwp, stack_t *ss, gregset_t rs, lwpstatus_t *lwpstatus) {
 273   char lwpstatusfile[PROCFILE_LENGTH];
 274   int lwpfd, err;
 275 
 276   if (err = os::Solaris::thr_getstate(tid, flags, lwp, ss, rs))
 277     return (err);
 278   if (*flags == TRS_LWPID) {
 279     sprintf(lwpstatusfile, "/proc/%d/lwp/%d/lwpstatus", getpid(),
 280             *lwp);
 281     if ((lwpfd = open(lwpstatusfile, O_RDONLY)) < 0) {
 282       perror("thr_mutator_status: open lwpstatus");
 283       return (EINVAL);
 284     }
 285     if (pread(lwpfd, lwpstatus, sizeof (lwpstatus_t), (off_t)0) !=
 286         sizeof (lwpstatus_t)) {
 287       perror("thr_mutator_status: read lwpstatus");
 288       (void) close(lwpfd);
 289       return (EINVAL);
 290     }
 291     (void) close(lwpfd);
 292   }
 293   return (0);
 294 }
 295 
 296 #ifndef AMD64
 297 
 298 // Detecting SSE support by OS
 299 // From solaris_i486.s
 300 extern "C" bool sse_check();
 301 extern "C" bool sse_unavailable();
 302 
 303 enum { SSE_UNKNOWN, SSE_NOT_SUPPORTED, SSE_SUPPORTED};
 304 static int sse_status = SSE_UNKNOWN;
 305 
 306 
 307 static void  check_for_sse_support() {
 308   if (!VM_Version::supports_sse()) {
 309     sse_status = SSE_NOT_SUPPORTED;
 310     return;
 311   }
 312   // looking for _sse_hw in libc.so, if it does not exist or
 313   // the value (int) is 0, OS has no support for SSE
 314   int *sse_hwp;
 315   void *h;
 316 
 317   if ((h=dlopen("/usr/lib/libc.so", RTLD_LAZY)) == NULL) {
 318     //open failed, presume no support for SSE
 319     sse_status = SSE_NOT_SUPPORTED;
 320     return;
 321   }
 322   if ((sse_hwp = (int *)dlsym(h, "_sse_hw")) == NULL) {
 323     sse_status = SSE_NOT_SUPPORTED;
 324   } else if (*sse_hwp == 0) {
 325     sse_status = SSE_NOT_SUPPORTED;
 326   }
 327   dlclose(h);
 328 
 329   if (sse_status == SSE_UNKNOWN) {
 330     bool (*try_sse)() = (bool (*)())sse_check;
 331     sse_status = (*try_sse)() ? SSE_SUPPORTED : SSE_NOT_SUPPORTED;
 332   }
 333 
 334 }
 335 
 336 #endif // AMD64
 337 
 338 bool os::supports_sse() {
 339 #ifdef AMD64
 340   return true;
 341 #else
 342   if (sse_status == SSE_UNKNOWN)
 343     check_for_sse_support();
 344   return sse_status == SSE_SUPPORTED;
 345 #endif // AMD64
 346 }
 347 
 348 bool os::is_allocatable(size_t bytes) {
 349 #ifdef AMD64
 350   return true;
 351 #else
 352 
 353   if (bytes < 2 * G) {
 354     return true;
 355   }
 356 
 357   char* addr = reserve_memory(bytes, NULL);
 358 
 359   if (addr != NULL) {
 360     release_memory(addr, bytes);
 361   }
 362 
 363   return addr != NULL;
 364 #endif // AMD64
 365 
 366 }
 367 
 368 extern "C" void Fetch32PFI () ;
 369 extern "C" void Fetch32Resume () ;
 370 #ifdef AMD64
 371 extern "C" void FetchNPFI () ;
 372 extern "C" void FetchNResume () ;
 373 #endif // AMD64
 374 
 375 extern "C" JNIEXPORT int
 376 JVM_handle_solaris_signal(int sig, siginfo_t* info, void* ucVoid,
 377                           int abort_if_unrecognized) {
 378   ucontext_t* uc = (ucontext_t*) ucVoid;
 379 
 380 #ifndef AMD64
 381   if (sig == SIGILL && info->si_addr == (caddr_t)sse_check) {
 382     // the SSE instruction faulted. supports_sse() need return false.
 383     uc->uc_mcontext.gregs[EIP] = (greg_t)sse_unavailable;
 384     return true;
 385   }
 386 #endif // !AMD64
 387 
 388   Thread* t = ThreadLocalStorage::get_thread_slow();  // slow & steady
 389 
 390   SignalHandlerMark shm(t);
 391 
 392   if(sig == SIGPIPE || sig == SIGXFSZ) {
 393     if (os::Solaris::chained_handler(sig, info, ucVoid)) {
 394       return true;
 395     } else {
 396       if (PrintMiscellaneous && (WizardMode || Verbose)) {
 397         char buf[64];
 398         warning("Ignoring %s - see 4229104 or 6499219",
 399                 os::exception_name(sig, buf, sizeof(buf)));
 400 
 401       }
 402       return true;
 403     }
 404   }
 405 
 406   JavaThread* thread = NULL;
 407   VMThread* vmthread = NULL;
 408 
 409   if (os::Solaris::signal_handlers_are_installed) {
 410     if (t != NULL ){
 411       if(t->is_Java_thread()) {
 412         thread = (JavaThread*)t;
 413       }
 414       else if(t->is_VM_thread()){
 415         vmthread = (VMThread *)t;
 416       }
 417     }
 418   }
 419 
 420   guarantee(sig != os::Solaris::SIGinterrupt(), "Can not chain VM interrupt signal, try -XX:+UseAltSigs");
 421 
 422   if (sig == os::Solaris::SIGasync()) {
 423     if(thread){
 424       OSThread::InterruptArguments args(thread, uc);
 425       thread->osthread()->do_interrupt_callbacks_at_interrupt(&args);
 426       return true;
 427     }
 428     else if(vmthread){
 429       OSThread::InterruptArguments args(vmthread, uc);
 430       vmthread->osthread()->do_interrupt_callbacks_at_interrupt(&args);
 431       return true;
 432     } else if (os::Solaris::chained_handler(sig, info, ucVoid)) {
 433       return true;
 434     } else {
 435       // If os::Solaris::SIGasync not chained, and this is a non-vm and
 436       // non-java thread
 437       return true;
 438     }
 439   }
 440 
 441   if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
 442     // can't decode this kind of signal
 443     info = NULL;
 444   } else {
 445     assert(sig == info->si_signo, "bad siginfo");
 446   }
 447 
 448   // decide if this trap can be handled by a stub
 449   address stub = NULL;
 450 
 451   address pc          = NULL;
 452 
 453   //%note os_trap_1
 454   if (info != NULL && uc != NULL && thread != NULL) {
 455     // factor me: getPCfromContext
 456     pc = (address) uc->uc_mcontext.gregs[REG_PC];
 457 
 458     // SafeFetch32() support
 459     if (pc == (address) Fetch32PFI) {
 460       uc->uc_mcontext.gregs[REG_PC] = intptr_t(Fetch32Resume) ;
 461       return true ;
 462     }
 463 #ifdef AMD64
 464     if (pc == (address) FetchNPFI) {
 465        uc->uc_mcontext.gregs [REG_PC] = intptr_t(FetchNResume) ;
 466        return true ;
 467     }
 468 #endif // AMD64
 469 
 470     // Handle ALL stack overflow variations here
 471     if (sig == SIGSEGV && info->si_code == SEGV_ACCERR) {
 472       address addr = (address) info->si_addr;
 473       if (thread->in_stack_yellow_zone(addr)) {
 474         thread->disable_stack_yellow_zone();
 475         if (thread->thread_state() == _thread_in_Java) {
 476           // Throw a stack overflow exception.  Guard pages will be reenabled
 477           // while unwinding the stack.
 478           stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
 479         } else {
 480           // Thread was in the vm or native code.  Return and try to finish.
 481           return true;
 482         }
 483       } else if (thread->in_stack_red_zone(addr)) {
 484         // Fatal red zone violation.  Disable the guard pages and fall through
 485         // to handle_unexpected_exception way down below.
 486         thread->disable_stack_red_zone();
 487         tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
 488       }
 489     }
 490 
 491     if (thread->thread_state() == _thread_in_vm) {
 492       if (sig == SIGBUS && info->si_code == BUS_OBJERR && thread->doing_unsafe_access()) {
 493         stub = StubRoutines::handler_for_unsafe_access();
 494       }
 495     }
 496 
 497     if (thread->thread_state() == _thread_in_Java) {
 498       // Support Safepoint Polling
 499       if ( sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
 500         stub = SharedRuntime::get_poll_stub(pc);
 501       }
 502       else if (sig == SIGBUS && info->si_code == BUS_OBJERR) {
 503         // BugId 4454115: A read from a MappedByteBuffer can fault
 504         // here if the underlying file has been truncated.
 505         // Do not crash the VM in such a case.
 506         CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
 507         nmethod* nm = cb->is_nmethod() ? (nmethod*)cb : NULL;
 508         if (nm != NULL && nm->has_unsafe_access()) {
 509           stub = StubRoutines::handler_for_unsafe_access();
 510         }
 511       }
 512       else
 513       if (sig == SIGFPE && info->si_code == FPE_INTDIV) {
 514         // integer divide by zero
 515         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
 516       }
 517 #ifndef AMD64
 518       else if (sig == SIGFPE && info->si_code == FPE_FLTDIV) {
 519         // floating-point divide by zero
 520         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
 521       }
 522       else if (sig == SIGFPE && info->si_code == FPE_FLTINV) {
 523         // The encoding of D2I in i486.ad can cause an exception prior
 524         // to the fist instruction if there was an invalid operation
 525         // pending. We want to dismiss that exception. From the win_32
 526         // side it also seems that if it really was the fist causing
 527         // the exception that we do the d2i by hand with different
 528         // rounding. Seems kind of weird. QQQ TODO
 529         // Note that we take the exception at the NEXT floating point instruction.
 530         if (pc[0] == 0xDB) {
 531             assert(pc[0] == 0xDB, "not a FIST opcode");
 532             assert(pc[1] == 0x14, "not a FIST opcode");
 533             assert(pc[2] == 0x24, "not a FIST opcode");
 534             return true;
 535         } else {
 536             assert(pc[-3] == 0xDB, "not an flt invalid opcode");
 537             assert(pc[-2] == 0x14, "not an flt invalid opcode");
 538             assert(pc[-1] == 0x24, "not an flt invalid opcode");
 539         }
 540       }
 541       else if (sig == SIGFPE ) {
 542         tty->print_cr("caught SIGFPE, info 0x%x.", info->si_code);
 543       }
 544 #endif // !AMD64
 545 
 546         // QQQ It doesn't seem that we need to do this on x86 because we should be able
 547         // to return properly from the handler without this extra stuff on the back side.
 548 
 549       else if (sig == SIGSEGV && info->si_code > 0 && !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
 550         // Determination of interpreter/vtable stub/compiled code null exception
 551         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
 552       }
 553     }
 554 
 555     // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
 556     // and the heap gets shrunk before the field access.
 557     if ((sig == SIGSEGV) || (sig == SIGBUS)) {
 558       address addr = JNI_FastGetField::find_slowcase_pc(pc);
 559       if (addr != (address)-1) {
 560         stub = addr;
 561       }
 562     }
 563 
 564     // Check to see if we caught the safepoint code in the
 565     // process of write protecting the memory serialization page.
 566     // It write enables the page immediately after protecting it
 567     // so we can just return to retry the write.
 568     if ((sig == SIGSEGV) &&
 569         os::is_memory_serialize_page(thread, (address)info->si_addr)) {
 570       // Block current thread until the memory serialize page permission restored.
 571       os::block_on_serialize_page_trap();
 572       return true;
 573     }
 574   }
 575 
 576   // Execution protection violation
 577   //
 578   // Preventative code for future versions of Solaris which may
 579   // enable execution protection when running the 32-bit VM on AMD64.
 580   //
 581   // This should be kept as the last step in the triage.  We don't
 582   // have a dedicated trap number for a no-execute fault, so be
 583   // conservative and allow other handlers the first shot.
 584   //
 585   // Note: We don't test that info->si_code == SEGV_ACCERR here.
 586   // this si_code is so generic that it is almost meaningless; and
 587   // the si_code for this condition may change in the future.
 588   // Furthermore, a false-positive should be harmless.
 589   if (UnguardOnExecutionViolation > 0 &&
 590       (sig == SIGSEGV || sig == SIGBUS) &&
 591       uc->uc_mcontext.gregs[TRAPNO] == T_PGFLT) {  // page fault
 592     int page_size = os::vm_page_size();
 593     address addr = (address) info->si_addr;
 594     address pc = (address) uc->uc_mcontext.gregs[REG_PC];
 595     // Make sure the pc and the faulting address are sane.
 596     //
 597     // If an instruction spans a page boundary, and the page containing
 598     // the beginning of the instruction is executable but the following
 599     // page is not, the pc and the faulting address might be slightly
 600     // different - we still want to unguard the 2nd page in this case.
 601     //
 602     // 15 bytes seems to be a (very) safe value for max instruction size.
 603     bool pc_is_near_addr =
 604       (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
 605     bool instr_spans_page_boundary =
 606       (align_size_down((intptr_t) pc ^ (intptr_t) addr,
 607                        (intptr_t) page_size) > 0);
 608 
 609     if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
 610       static volatile address last_addr =
 611         (address) os::non_memory_address_word();
 612 
 613       // In conservative mode, don't unguard unless the address is in the VM
 614       if (addr != last_addr &&
 615           (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
 616 
 617         // Make memory rwx and retry
 618         address page_start =
 619           (address) align_size_down((intptr_t) addr, (intptr_t) page_size);
 620         bool res = os::protect_memory((char*) page_start, page_size,
 621                                       os::MEM_PROT_RWX);
 622 
 623         if (PrintMiscellaneous && Verbose) {
 624           char buf[256];
 625           jio_snprintf(buf, sizeof(buf), "Execution protection violation "
 626                        "at " INTPTR_FORMAT
 627                        ", unguarding " INTPTR_FORMAT ": %s, errno=%d", addr,
 628                        page_start, (res ? "success" : "failed"), errno);
 629           tty->print_raw_cr(buf);
 630         }
 631         stub = pc;
 632 
 633         // Set last_addr so if we fault again at the same address, we don't end
 634         // up in an endless loop.
 635         //
 636         // There are two potential complications here.  Two threads trapping at
 637         // the same address at the same time could cause one of the threads to
 638         // think it already unguarded, and abort the VM.  Likely very rare.
 639         //
 640         // The other race involves two threads alternately trapping at
 641         // different addresses and failing to unguard the page, resulting in
 642         // an endless loop.  This condition is probably even more unlikely than
 643         // the first.
 644         //
 645         // Although both cases could be avoided by using locks or thread local
 646         // last_addr, these solutions are unnecessary complication: this
 647         // handler is a best-effort safety net, not a complete solution.  It is
 648         // disabled by default and should only be used as a workaround in case
 649         // we missed any no-execute-unsafe VM code.
 650 
 651         last_addr = addr;
 652       }
 653     }
 654   }
 655 
 656   if (stub != NULL) {
 657     // save all thread context in case we need to restore it
 658 
 659     if (thread != NULL) thread->set_saved_exception_pc(pc);
 660     // 12/02/99: On Sparc it appears that the full context is also saved
 661     // but as yet, no one looks at or restores that saved context
 662     // factor me: setPC
 663     uc->uc_mcontext.gregs[REG_PC] = (greg_t)stub;
 664     return true;
 665   }
 666 
 667   // signal-chaining
 668   if (os::Solaris::chained_handler(sig, info, ucVoid)) {
 669     return true;
 670   }
 671 
 672 #ifndef AMD64
 673   // Workaround (bug 4900493) for Solaris kernel bug 4966651.
 674   // Handle an undefined selector caused by an attempt to assign
 675   // fs in libthread getipriptr(). With the current libthread design every 512
 676   // thread creations the LDT for a private thread data structure is extended
 677   // and thre is a hazard that and another thread attempting a thread creation
 678   // will use a stale LDTR that doesn't reflect the structure's growth,
 679   // causing a GP fault.
 680   // Enforce the probable limit of passes through here to guard against an
 681   // infinite loop if some other move to fs caused the GP fault. Note that
 682   // this loop counter is ultimately a heuristic as it is possible for
 683   // more than one thread to generate this fault at a time in an MP system.
 684   // In the case of the loop count being exceeded or if the poll fails
 685   // just fall through to a fatal error.
 686   // If there is some other source of T_GPFLT traps and the text at EIP is
 687   // unreadable this code will loop infinitely until the stack is exausted.
 688   // The key to diagnosis in this case is to look for the bottom signal handler
 689   // frame.
 690 
 691   if(! IgnoreLibthreadGPFault) {
 692     if (sig == SIGSEGV && uc->uc_mcontext.gregs[TRAPNO] == T_GPFLT) {
 693       const unsigned char *p =
 694                         (unsigned const char *) uc->uc_mcontext.gregs[EIP];
 695 
 696       // Expected instruction?
 697 
 698       if(p[0] == movlfs[0] && p[1] == movlfs[1]) {
 699 
 700         Atomic::inc(&ldtr_refresh);
 701 
 702         // Infinite loop?
 703 
 704         if(ldtr_refresh < ((2 << 16) / PAGESIZE)) {
 705 
 706           // No, force scheduling to get a fresh view of the LDTR
 707 
 708           if(poll(NULL, 0, 10) == 0) {
 709 
 710             // Retry the move
 711 
 712             return false;
 713           }
 714         }
 715       }
 716     }
 717   }
 718 #endif // !AMD64
 719 
 720   if (!abort_if_unrecognized) {
 721     // caller wants another chance, so give it to him
 722     return false;
 723   }
 724 
 725   if (!os::Solaris::libjsig_is_loaded) {
 726     struct sigaction oldAct;
 727     sigaction(sig, (struct sigaction *)0, &oldAct);
 728     if (oldAct.sa_sigaction != signalHandler) {
 729       void* sighand = oldAct.sa_sigaction ? CAST_FROM_FN_PTR(void*,  oldAct.sa_sigaction)
 730                                           : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
 731       warning("Unexpected Signal %d occurred under user-defined signal handler %#lx", sig, (long)sighand);
 732     }
 733   }
 734 
 735   if (pc == NULL && uc != NULL) {
 736     pc = (address) uc->uc_mcontext.gregs[REG_PC];
 737   }
 738 
 739   // unmask current signal
 740   sigset_t newset;
 741   sigemptyset(&newset);
 742   sigaddset(&newset, sig);
 743   sigprocmask(SIG_UNBLOCK, &newset, NULL);
 744 
 745   // Determine which sort of error to throw.  Out of swap may signal
 746   // on the thread stack, which could get a mapping error when touched.
 747   address addr = (address) info->si_addr;
 748   if (sig == SIGBUS && info->si_code == BUS_OBJERR && info->si_errno == ENOMEM) {
 749     vm_exit_out_of_memory(0, "Out of swap space to map in thread stack.");
 750   }
 751 
 752   VMError err(t, sig, pc, info, ucVoid);
 753   err.report_and_die();
 754 
 755   ShouldNotReachHere();
 756 }
 757 
 758 void os::print_context(outputStream *st, void *context) {
 759   if (context == NULL) return;
 760 
 761   ucontext_t *uc = (ucontext_t*)context;
 762   st->print_cr("Registers:");
 763 #ifdef AMD64
 764   st->print(  "RAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RAX]);
 765   st->print(", RBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBX]);
 766   st->print(", RCX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RCX]);
 767   st->print(", RDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDX]);
 768   st->cr();
 769   st->print(  "RSP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSP]);
 770   st->print(", RBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBP]);
 771   st->print(", RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]);
 772   st->print(", RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]);
 773   st->cr();
 774   st->print(  "R8 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
 775   st->print(", R9 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]);
 776   st->print(", R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]);
 777   st->print(", R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]);
 778   st->cr();
 779   st->print(  "R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
 780   st->print(", R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]);
 781   st->print(", R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]);
 782   st->print(", R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]);
 783   st->cr();
 784   st->print(  "RIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RIP]);
 785   st->print(", RFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RFL]);
 786 #else
 787   st->print(  "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EAX]);
 788   st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EBX]);
 789   st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[ECX]);
 790   st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EDX]);
 791   st->cr();
 792   st->print(  "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[UESP]);
 793   st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EBP]);
 794   st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[ESI]);
 795   st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EDI]);
 796   st->cr();
 797   st->print(  "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EIP]);
 798   st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EFL]);
 799 #endif // AMD64
 800   st->cr();
 801   st->cr();
 802 
 803   intptr_t *sp = (intptr_t *)os::Solaris::ucontext_get_sp(uc);
 804   st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", sp);
 805   print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t));
 806   st->cr();
 807 
 808   // Note: it may be unsafe to inspect memory near pc. For example, pc may
 809   // point to garbage if entry point in an nmethod is corrupted. Leave
 810   // this at the end, and hope for the best.
 811   ExtendedPC epc = os::Solaris::ucontext_get_ExtendedPC(uc);
 812   address pc = epc.pc();
 813   st->print_cr("Instructions: (pc=" PTR_FORMAT ")", pc);
 814   print_hex_dump(st, pc - 32, pc + 32, sizeof(char));
 815 }
 816 
 817 void os::print_register_info(outputStream *st, void *context) {
 818   if (context == NULL) return;
 819 
 820   ucontext_t *uc = (ucontext_t*)context;
 821 
 822   st->print_cr("Register to memory mapping:");
 823   st->cr();
 824 
 825   // this is horrendously verbose but the layout of the registers in the
 826   // context does not match how we defined our abstract Register set, so
 827   // we can't just iterate through the gregs area
 828 
 829   // this is only for the "general purpose" registers
 830 
 831 #ifdef AMD64
 832   st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
 833   st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
 834   st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
 835   st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
 836   st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
 837   st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
 838   st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
 839   st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
 840   st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
 841   st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
 842   st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
 843   st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
 844   st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
 845   st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
 846   st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
 847   st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
 848 #else
 849   st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[EAX]);
 850   st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[EBX]);
 851   st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[ECX]);
 852   st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[EDX]);
 853   st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[UESP]);
 854   st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[EBP]);
 855   st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[ESI]);
 856   st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[EDI]);
 857 #endif
 858 
 859   st->cr();
 860 }
 861 
 862 
 863 #ifdef AMD64
 864 void os::Solaris::init_thread_fpu_state(void) {
 865   // Nothing to do
 866 }
 867 #else
 868 // From solaris_i486.s
 869 extern "C" void fixcw();
 870 
 871 void os::Solaris::init_thread_fpu_state(void) {
 872   // Set fpu to 53 bit precision. This happens too early to use a stub.
 873   fixcw();
 874 }
 875 
 876 // These routines are the initial value of atomic_xchg_entry(),
 877 // atomic_cmpxchg_entry(), atomic_inc_entry() and fence_entry()
 878 // until initialization is complete.
 879 // TODO - replace with .il implementation when compiler supports it.
 880 
 881 typedef jint  xchg_func_t        (jint,  volatile jint*);
 882 typedef jint  cmpxchg_func_t     (jint,  volatile jint*,  jint);
 883 typedef jlong cmpxchg_long_func_t(jlong, volatile jlong*, jlong);
 884 typedef jint  add_func_t         (jint,  volatile jint*);
 885 
 886 jint os::atomic_xchg_bootstrap(jint exchange_value, volatile jint* dest) {
 887   // try to use the stub:
 888   xchg_func_t* func = CAST_TO_FN_PTR(xchg_func_t*, StubRoutines::atomic_xchg_entry());
 889 
 890   if (func != NULL) {
 891     os::atomic_xchg_func = func;
 892     return (*func)(exchange_value, dest);
 893   }
 894   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 895 
 896   jint old_value = *dest;
 897   *dest = exchange_value;
 898   return old_value;
 899 }
 900 
 901 jint os::atomic_cmpxchg_bootstrap(jint exchange_value, volatile jint* dest, jint compare_value) {
 902   // try to use the stub:
 903   cmpxchg_func_t* func = CAST_TO_FN_PTR(cmpxchg_func_t*, StubRoutines::atomic_cmpxchg_entry());
 904 
 905   if (func != NULL) {
 906     os::atomic_cmpxchg_func = func;
 907     return (*func)(exchange_value, dest, compare_value);
 908   }
 909   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 910 
 911   jint old_value = *dest;
 912   if (old_value == compare_value)
 913     *dest = exchange_value;
 914   return old_value;
 915 }
 916 
 917 jlong os::atomic_cmpxchg_long_bootstrap(jlong exchange_value, volatile jlong* dest, jlong compare_value) {
 918   // try to use the stub:
 919   cmpxchg_long_func_t* func = CAST_TO_FN_PTR(cmpxchg_long_func_t*, StubRoutines::atomic_cmpxchg_long_entry());
 920 
 921   if (func != NULL) {
 922     os::atomic_cmpxchg_long_func = func;
 923     return (*func)(exchange_value, dest, compare_value);
 924   }
 925   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 926 
 927   jlong old_value = *dest;
 928   if (old_value == compare_value)
 929     *dest = exchange_value;
 930   return old_value;
 931 }
 932 
 933 jint os::atomic_add_bootstrap(jint add_value, volatile jint* dest) {
 934   // try to use the stub:
 935   add_func_t* func = CAST_TO_FN_PTR(add_func_t*, StubRoutines::atomic_add_entry());
 936 
 937   if (func != NULL) {
 938     os::atomic_add_func = func;
 939     return (*func)(add_value, dest);
 940   }
 941   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 942 
 943   return (*dest) += add_value;
 944 }
 945 
 946 xchg_func_t*         os::atomic_xchg_func         = os::atomic_xchg_bootstrap;
 947 cmpxchg_func_t*      os::atomic_cmpxchg_func      = os::atomic_cmpxchg_bootstrap;
 948 cmpxchg_long_func_t* os::atomic_cmpxchg_long_func = os::atomic_cmpxchg_long_bootstrap;
 949 add_func_t*          os::atomic_add_func          = os::atomic_add_bootstrap;
 950 
 951 extern "C" void _solaris_raw_setup_fpu(address ptr);
 952 void os::setup_fpu() {
 953   address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
 954   _solaris_raw_setup_fpu(fpu_cntrl);
 955 }
 956 #endif // AMD64
 957 
 958 #ifndef PRODUCT
 959 void os::verify_stack_alignment() {
 960 #ifdef AMD64
 961   assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
 962 #endif
 963 }
 964 #endif