1 /*
   2  * Copyright (c) 1999, 2019, 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 "jvm.h"
  27 #include "asm/macroAssembler.hpp"
  28 #include "classfile/classLoader.hpp"
  29 #include "classfile/systemDictionary.hpp"
  30 #include "classfile/vmSymbols.hpp"
  31 #include "code/codeCache.hpp"
  32 #include "code/icBuffer.hpp"
  33 #include "code/vtableStubs.hpp"
  34 #include "interpreter/interpreter.hpp"
  35 #include "logging/log.hpp"
  36 #include "memory/allocation.inline.hpp"
  37 #include "os_share_solaris.hpp"
  38 #include "prims/jniFastGetField.hpp"
  39 #include "prims/jvm_misc.hpp"
  40 #include "runtime/arguments.hpp"
  41 #include "runtime/atomic.hpp"
  42 #include "runtime/extendedPC.hpp"
  43 #include "runtime/frame.inline.hpp"
  44 #include "runtime/interfaceSupport.inline.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/thread.inline.hpp"
  52 #include "runtime/timer.hpp"
  53 #include "utilities/align.hpp"
  54 #include "utilities/events.hpp"
  55 #include "utilities/vmError.hpp"
  56 
  57 // put OS-includes here
  58 # include <sys/types.h>
  59 # include <sys/mman.h>
  60 # include <pthread.h>
  61 # include <signal.h>
  62 # include <setjmp.h>
  63 # include <errno.h>
  64 # include <dlfcn.h>
  65 # include <stdio.h>
  66 # include <unistd.h>
  67 # include <sys/resource.h>
  68 # include <thread.h>
  69 # include <sys/stat.h>
  70 # include <sys/time.h>
  71 # include <sys/filio.h>
  72 # include <sys/utsname.h>
  73 # include <sys/systeminfo.h>
  74 # include <sys/socket.h>
  75 # include <sys/trap.h>
  76 # include <sys/lwp.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 usable stack sizes required to get to user code. Space for
  91 // HotSpot guard pages is added later.
  92 #ifdef _LP64
  93 // The adlc generated method 'State::MachNodeGenerator(int)' used by the C2 compiler
  94 // threads requires a large stack with the Solaris Studio C++ compiler version 5.13
  95 // and product VM builds (debug builds require significantly less stack space).
  96 size_t os::Posix::_compiler_thread_min_stack_allowed = 325 * K;
  97 size_t os::Posix::_java_thread_min_stack_allowed = 48 * K;
  98 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 224 * K;
  99 #else
 100 size_t os::Posix::_compiler_thread_min_stack_allowed = 32 * K;
 101 size_t os::Posix::_java_thread_min_stack_allowed = 32 * K;
 102 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
 103 #endif // _LP64
 104 
 105 #ifdef AMD64
 106 #define REG_SP REG_RSP
 107 #define REG_PC REG_RIP
 108 #define REG_FP REG_RBP
 109 #else
 110 #define REG_SP UESP
 111 #define REG_PC EIP
 112 #define REG_FP EBP
 113 // 4900493 counter to prevent runaway LDTR refresh attempt
 114 
 115 static volatile int ldtr_refresh = 0;
 116 // the libthread instruction that faults because of the stale LDTR
 117 
 118 static const unsigned char movlfs[] = { 0x8e, 0xe0    // movl %eax,%fs
 119                        };
 120 #endif // AMD64
 121 
 122 char* os::non_memory_address_word() {
 123   // Must never look like an address returned by reserve_memory,
 124   // even in its subfields (as defined by the CPU immediate fields,
 125   // if the CPU splits constants across multiple instructions).
 126   return (char*) -1;
 127 }
 128 
 129 //
 130 // Validate a ucontext retrieved from walking a uc_link of a ucontext.
 131 // There are issues with libthread giving out uc_links for different threads
 132 // on the same uc_link chain and bad or circular links.
 133 //
 134 bool os::Solaris::valid_ucontext(Thread* thread, const ucontext_t* valid, const ucontext_t* suspect) {
 135   if (valid >= suspect ||
 136       valid->uc_stack.ss_flags != suspect->uc_stack.ss_flags ||
 137       valid->uc_stack.ss_sp    != suspect->uc_stack.ss_sp    ||
 138       valid->uc_stack.ss_size  != suspect->uc_stack.ss_size) {
 139     DEBUG_ONLY(tty->print_cr("valid_ucontext: failed test 1");)
 140     return false;
 141   }
 142 
 143   if (thread->is_Java_thread()) {
 144     if (!valid_stack_address(thread, (address)suspect)) {
 145       DEBUG_ONLY(tty->print_cr("valid_ucontext: uc_link not in thread stack");)
 146       return false;
 147     }
 148     if (!valid_stack_address(thread,  (address) suspect->uc_mcontext.gregs[REG_SP])) {
 149       DEBUG_ONLY(tty->print_cr("valid_ucontext: stackpointer not in thread stack");)
 150       return false;
 151     }
 152   }
 153   return true;
 154 }
 155 
 156 // We will only follow one level of uc_link since there are libthread
 157 // issues with ucontext linking and it is better to be safe and just
 158 // let caller retry later.
 159 const ucontext_t* os::Solaris::get_valid_uc_in_signal_handler(Thread *thread,
 160   const ucontext_t *uc) {
 161 
 162   const ucontext_t *retuc = NULL;
 163 
 164   if (uc != NULL) {
 165     if (uc->uc_link == NULL) {
 166       // cannot validate without uc_link so accept current ucontext
 167       retuc = uc;
 168     } else if (os::Solaris::valid_ucontext(thread, uc, uc->uc_link)) {
 169       // first ucontext is valid so try the next one
 170       uc = uc->uc_link;
 171       if (uc->uc_link == NULL) {
 172         // cannot validate without uc_link so accept current ucontext
 173         retuc = uc;
 174       } else if (os::Solaris::valid_ucontext(thread, uc, uc->uc_link)) {
 175         // the ucontext one level down is also valid so return it
 176         retuc = uc;
 177       }
 178     }
 179   }
 180   return retuc;
 181 }
 182 
 183 // Assumes ucontext is valid
 184 ExtendedPC os::Solaris::ucontext_get_ExtendedPC(const ucontext_t *uc) {
 185   return ExtendedPC((address)uc->uc_mcontext.gregs[REG_PC]);
 186 }
 187 
 188 void os::Solaris::ucontext_set_pc(ucontext_t* uc, address pc) {
 189   uc->uc_mcontext.gregs [REG_PC]  = (greg_t) pc;
 190 }
 191 
 192 // Assumes ucontext is valid
 193 intptr_t* os::Solaris::ucontext_get_sp(const ucontext_t *uc) {
 194   return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
 195 }
 196 
 197 // Assumes ucontext is valid
 198 intptr_t* os::Solaris::ucontext_get_fp(const ucontext_t *uc) {
 199   return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
 200 }
 201 
 202 address os::Solaris::ucontext_get_pc(const ucontext_t *uc) {
 203   return (address) uc->uc_mcontext.gregs[REG_PC];
 204 }
 205 
 206 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
 207 // is currently interrupted by SIGPROF.
 208 //
 209 // The difference between this and os::fetch_frame_from_context() is that
 210 // here we try to skip nested signal frames.
 211 // This method is also used for stack overflow signal handling.
 212 ExtendedPC os::Solaris::fetch_frame_from_ucontext(Thread* thread,
 213   const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
 214 
 215   assert(thread != NULL, "just checking");
 216   assert(ret_sp != NULL, "just checking");
 217   assert(ret_fp != NULL, "just checking");
 218 
 219   const ucontext_t *luc = os::Solaris::get_valid_uc_in_signal_handler(thread, uc);
 220   return os::fetch_frame_from_context(luc, ret_sp, ret_fp);
 221 }
 222 
 223 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
 224                     intptr_t** ret_sp, intptr_t** ret_fp) {
 225 
 226   ExtendedPC  epc;
 227   const ucontext_t *uc = (const ucontext_t*)ucVoid;
 228 
 229   if (uc != NULL) {
 230     epc = os::Solaris::ucontext_get_ExtendedPC(uc);
 231     if (ret_sp) *ret_sp = os::Solaris::ucontext_get_sp(uc);
 232     if (ret_fp) *ret_fp = os::Solaris::ucontext_get_fp(uc);
 233   } else {
 234     // construct empty ExtendedPC for return value checking
 235     epc = ExtendedPC(NULL);
 236     if (ret_sp) *ret_sp = (intptr_t *)NULL;
 237     if (ret_fp) *ret_fp = (intptr_t *)NULL;
 238   }
 239 
 240   return epc;
 241 }
 242 
 243 frame os::fetch_frame_from_context(const void* ucVoid) {
 244   intptr_t* sp;
 245   intptr_t* fp;
 246   ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
 247   return frame(sp, fp, epc.pc());
 248 }
 249 
 250 frame os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) {
 251   intptr_t* sp;
 252   intptr_t* fp;
 253   ExtendedPC epc = os::Solaris::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, &fp);
 254   return frame(sp, fp, epc.pc());
 255 }
 256 
 257 bool os::Solaris::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
 258  address pc = (address) os::Solaris::ucontext_get_pc(uc);
 259   if (Interpreter::contains(pc)) {
 260     // interpreter performs stack banging after the fixed frame header has
 261     // been generated while the compilers perform it before. To maintain
 262     // semantic consistency between interpreted and compiled frames, the
 263     // method returns the Java sender of the current frame.
 264     *fr = os::fetch_frame_from_ucontext(thread, uc);
 265     if (!fr->is_first_java_frame()) {
 266       // get_frame_at_stack_banging_point() is only called when we
 267       // have well defined stacks so java_sender() calls do not need
 268       // to assert safe_for_sender() first.
 269       *fr = fr->java_sender();
 270     }
 271   } else {
 272     // more complex code with compiled code
 273     assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
 274     CodeBlob* cb = CodeCache::find_blob(pc);
 275     if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
 276       // Not sure where the pc points to, fallback to default
 277       // stack overflow handling
 278       return false;
 279     } else {
 280       // in compiled code, the stack banging is performed just after the return pc
 281       // has been pushed on the stack
 282       intptr_t* fp = os::Solaris::ucontext_get_fp(uc);
 283       intptr_t* sp = os::Solaris::ucontext_get_sp(uc);
 284       *fr = frame(sp + 1, fp, (address)*sp);
 285       if (!fr->is_java_frame()) {
 286         // See java_sender() comment above.
 287         *fr = fr->java_sender();
 288       }
 289     }
 290   }
 291   assert(fr->is_java_frame(), "Safety check");
 292   return true;
 293 }
 294 
 295 frame os::get_sender_for_C_frame(frame* fr) {
 296   return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
 297 }
 298 
 299 extern "C" intptr_t *_get_current_sp();  // in .il file
 300 
 301 address os::current_stack_pointer() {
 302   return (address)_get_current_sp();
 303 }
 304 
 305 extern "C" intptr_t *_get_current_fp();  // in .il file
 306 
 307 frame os::current_frame() {
 308   intptr_t* fp = _get_current_fp();  // it's inlined so want current fp
 309   // fp is for os::current_frame. We want the fp for our caller.
 310   frame myframe((intptr_t*)os::current_stack_pointer(),
 311                 (intptr_t*)fp,
 312                 CAST_FROM_FN_PTR(address, os::current_frame));
 313   frame caller_frame = os::get_sender_for_C_frame(&myframe);
 314 
 315   if (os::is_first_C_frame(&caller_frame)) {
 316     // stack is not walkable
 317     frame ret; // This will be a null useless frame
 318     return ret;
 319   } else {
 320     // return frame for our caller's caller
 321     return os::get_sender_for_C_frame(&caller_frame);
 322   }
 323 }
 324 
 325 #ifndef AMD64
 326 
 327 // Detecting SSE support by OS
 328 // From solaris_i486.s
 329 extern "C" bool sse_check();
 330 extern "C" bool sse_unavailable();
 331 
 332 enum { SSE_UNKNOWN, SSE_NOT_SUPPORTED, SSE_SUPPORTED};
 333 static int sse_status = SSE_UNKNOWN;
 334 
 335 
 336 static void  check_for_sse_support() {
 337   if (!VM_Version::supports_sse()) {
 338     sse_status = SSE_NOT_SUPPORTED;
 339     return;
 340   }
 341   // looking for _sse_hw in libc.so, if it does not exist or
 342   // the value (int) is 0, OS has no support for SSE
 343   int *sse_hwp;
 344   void *h;
 345 
 346   if ((h=dlopen("/usr/lib/libc.so", RTLD_LAZY)) == NULL) {
 347     //open failed, presume no support for SSE
 348     sse_status = SSE_NOT_SUPPORTED;
 349     return;
 350   }
 351   if ((sse_hwp = (int *)dlsym(h, "_sse_hw")) == NULL) {
 352     sse_status = SSE_NOT_SUPPORTED;
 353   } else if (*sse_hwp == 0) {
 354     sse_status = SSE_NOT_SUPPORTED;
 355   }
 356   dlclose(h);
 357 
 358   if (sse_status == SSE_UNKNOWN) {
 359     bool (*try_sse)() = (bool (*)())sse_check;
 360     sse_status = (*try_sse)() ? SSE_SUPPORTED : SSE_NOT_SUPPORTED;
 361   }
 362 
 363 }
 364 
 365 #endif // AMD64
 366 
 367 bool os::supports_sse() {
 368 #ifdef AMD64
 369   return true;
 370 #else
 371   if (sse_status == SSE_UNKNOWN)
 372     check_for_sse_support();
 373   return sse_status == SSE_SUPPORTED;
 374 #endif // AMD64
 375 }
 376 
 377 bool os::is_allocatable(size_t bytes) {
 378 #ifdef AMD64
 379   return true;
 380 #else
 381 
 382   if (bytes < 2 * G) {
 383     return true;
 384   }
 385 
 386   char* addr = reserve_memory(bytes, NULL);
 387 
 388   if (addr != NULL) {
 389     release_memory(addr, bytes);
 390   }
 391 
 392   return addr != NULL;
 393 #endif // AMD64
 394 
 395 }
 396 
 397 extern "C" JNIEXPORT int
 398 JVM_handle_solaris_signal(int sig, siginfo_t* info, void* ucVoid,
 399                           int abort_if_unrecognized) {
 400   ucontext_t* uc = (ucontext_t*) ucVoid;
 401 
 402 #ifndef AMD64
 403   if (sig == SIGILL && info->si_addr == (caddr_t)sse_check) {
 404     // the SSE instruction faulted. supports_sse() need return false.
 405     uc->uc_mcontext.gregs[EIP] = (greg_t)sse_unavailable;
 406     return true;
 407   }
 408 #endif // !AMD64
 409 
 410   Thread* t = Thread::current_or_null_safe();
 411 
 412   // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
 413   // (no destructors can be run)
 414   os::ThreadCrashProtection::check_crash_protection(sig, t);
 415 
 416   SignalHandlerMark shm(t);
 417 
 418   if(sig == SIGPIPE || sig == SIGXFSZ) {
 419     if (os::Solaris::chained_handler(sig, info, ucVoid)) {
 420       return true;
 421     } else {
 422       // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
 423       return true;
 424     }
 425   }
 426 
 427   JavaThread* thread = NULL;
 428   VMThread* vmthread = NULL;
 429 
 430   if (os::Solaris::signal_handlers_are_installed) {
 431     if (t != NULL ){
 432       if(t->is_Java_thread()) {
 433         thread = (JavaThread*)t;
 434       }
 435       else if(t->is_VM_thread()){
 436         vmthread = (VMThread *)t;
 437       }
 438     }
 439   }
 440 
 441   if (sig == ASYNC_SIGNAL) {
 442     if(thread || vmthread){
 443       OSThread::SR_handler(t, uc);
 444       return true;
 445     } else if (os::Solaris::chained_handler(sig, info, ucVoid)) {
 446       return true;
 447     } else {
 448       // If ASYNC_SIGNAL not chained, and this is a non-vm and
 449       // non-java thread
 450       return true;
 451     }
 452   }
 453 
 454   if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
 455     // can't decode this kind of signal
 456     info = NULL;
 457   } else {
 458     assert(sig == info->si_signo, "bad siginfo");
 459   }
 460 
 461   // decide if this trap can be handled by a stub
 462   address stub = NULL;
 463 
 464   address pc          = NULL;
 465 
 466   //%note os_trap_1
 467   if (info != NULL && uc != NULL && thread != NULL) {
 468     // factor me: getPCfromContext
 469     pc = (address) uc->uc_mcontext.gregs[REG_PC];
 470 
 471     if (StubRoutines::is_safefetch_fault(pc)) {
 472       os::Solaris::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
 473       return true;
 474     }
 475 
 476     // Handle ALL stack overflow variations here
 477     if (sig == SIGSEGV && info->si_code == SEGV_ACCERR) {
 478       address addr = (address) info->si_addr;
 479       if (thread->in_stack_yellow_reserved_zone(addr)) {
 480         if (thread->thread_state() == _thread_in_Java) {
 481           if (thread->in_stack_reserved_zone(addr)) {
 482             frame fr;
 483             if (os::Solaris::get_frame_at_stack_banging_point(thread, uc, &fr)) {
 484               assert(fr.is_java_frame(), "Must be Java frame");
 485               frame activation = SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
 486               if (activation.sp() != NULL) {
 487                 thread->disable_stack_reserved_zone();
 488                 if (activation.is_interpreted_frame()) {
 489                   thread->set_reserved_stack_activation((address)(
 490                     activation.fp() + frame::interpreter_frame_initial_sp_offset));
 491                 } else {
 492                   thread->set_reserved_stack_activation((address)activation.unextended_sp());
 493                 }
 494                 return true;
 495               }
 496             }
 497           }
 498           // Throw a stack overflow exception.  Guard pages will be reenabled
 499           // while unwinding the stack.
 500           thread->disable_stack_yellow_reserved_zone();
 501           stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
 502         } else {
 503           // Thread was in the vm or native code.  Return and try to finish.
 504           thread->disable_stack_yellow_reserved_zone();
 505           return true;
 506         }
 507       } else if (thread->in_stack_red_zone(addr)) {
 508         // Fatal red zone violation.  Disable the guard pages and fall through
 509         // to handle_unexpected_exception way down below.
 510         thread->disable_stack_red_zone();
 511         tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
 512       }
 513     }
 514 
 515     if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) {
 516       // Verify that OS save/restore AVX registers.
 517       stub = VM_Version::cpuinfo_cont_addr();
 518     }
 519 
 520     if (thread->thread_state() == _thread_in_vm ||
 521          thread->thread_state() == _thread_in_native) {
 522       if (sig == SIGBUS && info->si_code == BUS_OBJERR && thread->doing_unsafe_access()) {
 523         address next_pc = Assembler::locate_next_instruction(pc);
 524         if (UnsafeCopyMemory::contains_pc(pc)) {
 525           next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
 526         }
 527         stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
 528       }
 529     }
 530 
 531     if (thread->thread_state() == _thread_in_Java) {
 532       // Support Safepoint Polling
 533       if ( sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
 534         stub = SharedRuntime::get_poll_stub(pc);
 535       }
 536       else if (sig == SIGBUS && info->si_code == BUS_OBJERR) {
 537         // BugId 4454115: A read from a MappedByteBuffer can fault
 538         // here if the underlying file has been truncated.
 539         // Do not crash the VM in such a case.
 540         CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
 541         if (cb != NULL) {
 542           CompiledMethod* nm = cb->as_compiled_method_or_null();
 543           bool is_unsafe_arraycopy = thread->doing_unsafe_access() && UnsafeCopyMemory::contains_pc(pc);
 544           if ((nm != NULL && nm->has_unsafe_access()) || is_unsafe_arraycopy) {
 545             address next_pc = Assembler::locate_next_instruction(pc);
 546             if (is_unsafe_arraycopy) {
 547               next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
 548             }
 549             stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
 550           }
 551         }
 552       }
 553       else
 554       if (sig == SIGFPE && info->si_code == FPE_INTDIV) {
 555         // integer divide by zero
 556         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
 557       }
 558 #ifndef AMD64
 559       else if (sig == SIGFPE && info->si_code == FPE_FLTDIV) {
 560         // floating-point divide by zero
 561         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
 562       }
 563       else if (sig == SIGFPE && info->si_code == FPE_FLTINV) {
 564         // The encoding of D2I in i486.ad can cause an exception prior
 565         // to the fist instruction if there was an invalid operation
 566         // pending. We want to dismiss that exception. From the win_32
 567         // side it also seems that if it really was the fist causing
 568         // the exception that we do the d2i by hand with different
 569         // rounding. Seems kind of weird. QQQ TODO
 570         // Note that we take the exception at the NEXT floating point instruction.
 571         if (pc[0] == 0xDB) {
 572             assert(pc[0] == 0xDB, "not a FIST opcode");
 573             assert(pc[1] == 0x14, "not a FIST opcode");
 574             assert(pc[2] == 0x24, "not a FIST opcode");
 575             return true;
 576         } else {
 577             assert(pc[-3] == 0xDB, "not an flt invalid opcode");
 578             assert(pc[-2] == 0x14, "not an flt invalid opcode");
 579             assert(pc[-1] == 0x24, "not an flt invalid opcode");
 580         }
 581       }
 582       else if (sig == SIGFPE ) {
 583         tty->print_cr("caught SIGFPE, info 0x%x.", info->si_code);
 584       }
 585 #endif // !AMD64
 586 
 587         // QQQ It doesn't seem that we need to do this on x86 because we should be able
 588         // to return properly from the handler without this extra stuff on the back side.
 589 
 590       else if (sig == SIGSEGV && info->si_code > 0 &&
 591                MacroAssembler::uses_implicit_null_check(info->si_addr)) {
 592         // Determination of interpreter/vtable stub/compiled code null exception
 593         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
 594       }
 595     }
 596 
 597     // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
 598     // and the heap gets shrunk before the field access.
 599     if ((sig == SIGSEGV) || (sig == SIGBUS)) {
 600       address addr = JNI_FastGetField::find_slowcase_pc(pc);
 601       if (addr != (address)-1) {
 602         stub = addr;
 603       }
 604     }
 605   }
 606 
 607   // Execution protection violation
 608   //
 609   // Preventative code for future versions of Solaris which may
 610   // enable execution protection when running the 32-bit VM on AMD64.
 611   //
 612   // This should be kept as the last step in the triage.  We don't
 613   // have a dedicated trap number for a no-execute fault, so be
 614   // conservative and allow other handlers the first shot.
 615   //
 616   // Note: We don't test that info->si_code == SEGV_ACCERR here.
 617   // this si_code is so generic that it is almost meaningless; and
 618   // the si_code for this condition may change in the future.
 619   // Furthermore, a false-positive should be harmless.
 620   if (UnguardOnExecutionViolation > 0 &&
 621       (sig == SIGSEGV || sig == SIGBUS) &&
 622       uc->uc_mcontext.gregs[TRAPNO] == T_PGFLT) {  // page fault
 623     int page_size = os::vm_page_size();
 624     address addr = (address) info->si_addr;
 625     address pc = (address) uc->uc_mcontext.gregs[REG_PC];
 626     // Make sure the pc and the faulting address are sane.
 627     //
 628     // If an instruction spans a page boundary, and the page containing
 629     // the beginning of the instruction is executable but the following
 630     // page is not, the pc and the faulting address might be slightly
 631     // different - we still want to unguard the 2nd page in this case.
 632     //
 633     // 15 bytes seems to be a (very) safe value for max instruction size.
 634     bool pc_is_near_addr =
 635       (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
 636     bool instr_spans_page_boundary =
 637       (align_down((intptr_t) pc ^ (intptr_t) addr,
 638                        (intptr_t) page_size) > 0);
 639 
 640     if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
 641       static volatile address last_addr =
 642         (address) os::non_memory_address_word();
 643 
 644       // In conservative mode, don't unguard unless the address is in the VM
 645       if (addr != last_addr &&
 646           (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
 647 
 648         // Make memory rwx and retry
 649         address page_start = align_down(addr, page_size);
 650         bool res = os::protect_memory((char*) page_start, page_size,
 651                                       os::MEM_PROT_RWX);
 652 
 653         log_debug(os)("Execution protection violation "
 654                       "at " INTPTR_FORMAT
 655                       ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr),
 656                       p2i(page_start), (res ? "success" : "failed"), errno);
 657         stub = pc;
 658 
 659         // Set last_addr so if we fault again at the same address, we don't end
 660         // up in an endless loop.
 661         //
 662         // There are two potential complications here.  Two threads trapping at
 663         // the same address at the same time could cause one of the threads to
 664         // think it already unguarded, and abort the VM.  Likely very rare.
 665         //
 666         // The other race involves two threads alternately trapping at
 667         // different addresses and failing to unguard the page, resulting in
 668         // an endless loop.  This condition is probably even more unlikely than
 669         // the first.
 670         //
 671         // Although both cases could be avoided by using locks or thread local
 672         // last_addr, these solutions are unnecessary complication: this
 673         // handler is a best-effort safety net, not a complete solution.  It is
 674         // disabled by default and should only be used as a workaround in case
 675         // we missed any no-execute-unsafe VM code.
 676 
 677         last_addr = addr;
 678       }
 679     }
 680   }
 681 
 682   if (stub != NULL) {
 683     // save all thread context in case we need to restore it
 684 
 685     if (thread != NULL) thread->set_saved_exception_pc(pc);
 686     // 12/02/99: On Sparc it appears that the full context is also saved
 687     // but as yet, no one looks at or restores that saved context
 688     os::Solaris::ucontext_set_pc(uc, stub);
 689     return true;
 690   }
 691 
 692   // signal-chaining
 693   if (os::Solaris::chained_handler(sig, info, ucVoid)) {
 694     return true;
 695   }
 696 
 697   if (!abort_if_unrecognized) {
 698     // caller wants another chance, so give it to him
 699     return false;
 700   }
 701 
 702   if (!os::Solaris::libjsig_is_loaded) {
 703     struct sigaction oldAct;
 704     sigaction(sig, (struct sigaction *)0, &oldAct);
 705     if (oldAct.sa_sigaction != signalHandler) {
 706       void* sighand = oldAct.sa_sigaction ? CAST_FROM_FN_PTR(void*,  oldAct.sa_sigaction)
 707                                           : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
 708       warning("Unexpected Signal %d occurred under user-defined signal handler %#lx", sig, (long)sighand);
 709     }
 710   }
 711 
 712   if (pc == NULL && uc != NULL) {
 713     pc = (address) uc->uc_mcontext.gregs[REG_PC];
 714   }
 715 
 716   // unmask current signal
 717   sigset_t newset;
 718   sigemptyset(&newset);
 719   sigaddset(&newset, sig);
 720   sigprocmask(SIG_UNBLOCK, &newset, NULL);
 721 
 722   // Determine which sort of error to throw.  Out of swap may signal
 723   // on the thread stack, which could get a mapping error when touched.
 724   address addr = (address) info->si_addr;
 725   if (sig == SIGBUS && info->si_code == BUS_OBJERR && info->si_errno == ENOMEM) {
 726     vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "Out of swap space to map in thread stack.");
 727   }
 728 
 729   VMError::report_and_die(t, sig, pc, info, ucVoid);
 730 
 731   ShouldNotReachHere();
 732   return false;
 733 }
 734 
 735 void os::print_context(outputStream *st, const void *context) {
 736   if (context == NULL) return;
 737 
 738   const ucontext_t *uc = (const ucontext_t*)context;
 739   st->print_cr("Registers:");
 740 #ifdef AMD64
 741   st->print(  "RAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RAX]);
 742   st->print(", RBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBX]);
 743   st->print(", RCX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RCX]);
 744   st->print(", RDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDX]);
 745   st->cr();
 746   st->print(  "RSP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSP]);
 747   st->print(", RBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBP]);
 748   st->print(", RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]);
 749   st->print(", RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]);
 750   st->cr();
 751   st->print(  "R8 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
 752   st->print(", R9 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]);
 753   st->print(", R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]);
 754   st->print(", R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]);
 755   st->cr();
 756   st->print(  "R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
 757   st->print(", R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]);
 758   st->print(", R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]);
 759   st->print(", R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]);
 760   st->cr();
 761   st->print(  "RIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RIP]);
 762   st->print(", RFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RFL]);
 763 #else
 764   st->print(  "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EAX]);
 765   st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EBX]);
 766   st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[ECX]);
 767   st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EDX]);
 768   st->cr();
 769   st->print(  "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[UESP]);
 770   st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EBP]);
 771   st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[ESI]);
 772   st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EDI]);
 773   st->cr();
 774   st->print(  "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EIP]);
 775   st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EFL]);
 776 #endif // AMD64
 777   st->cr();
 778   st->cr();
 779 
 780   intptr_t *sp = (intptr_t *)os::Solaris::ucontext_get_sp(uc);
 781   st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", sp);
 782   print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t));
 783   st->cr();
 784 
 785   // Note: it may be unsafe to inspect memory near pc. For example, pc may
 786   // point to garbage if entry point in an nmethod is corrupted. Leave
 787   // this at the end, and hope for the best.
 788   ExtendedPC epc = os::Solaris::ucontext_get_ExtendedPC(uc);
 789   address pc = epc.pc();
 790   print_instructions(st, pc, sizeof(char));
 791   st->cr();
 792 }
 793 
 794 void os::print_register_info(outputStream *st, const void *context) {
 795   if (context == NULL) return;
 796 
 797   const ucontext_t *uc = (const ucontext_t*)context;
 798 
 799   st->print_cr("Register to memory mapping:");
 800   st->cr();
 801 
 802   // this is horrendously verbose but the layout of the registers in the
 803   // context does not match how we defined our abstract Register set, so
 804   // we can't just iterate through the gregs area
 805 
 806   // this is only for the "general purpose" registers
 807 
 808 #ifdef AMD64
 809   st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
 810   st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
 811   st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
 812   st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
 813   st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
 814   st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
 815   st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
 816   st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
 817   st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
 818   st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
 819   st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
 820   st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
 821   st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
 822   st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
 823   st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
 824   st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
 825 #else
 826   st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[EAX]);
 827   st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[EBX]);
 828   st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[ECX]);
 829   st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[EDX]);
 830   st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[UESP]);
 831   st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[EBP]);
 832   st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[ESI]);
 833   st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[EDI]);
 834 #endif
 835 
 836   st->cr();
 837 }
 838 
 839 
 840 #ifdef AMD64
 841 void os::Solaris::init_thread_fpu_state(void) {
 842   // Nothing to do
 843 }
 844 #else
 845 // From solaris_i486.s
 846 extern "C" void fixcw();
 847 
 848 void os::Solaris::init_thread_fpu_state(void) {
 849   // Set fpu to 53 bit precision. This happens too early to use a stub.
 850   fixcw();
 851 }
 852 
 853 // These routines are the initial value of atomic_xchg_entry(),
 854 // atomic_cmpxchg_entry(), atomic_inc_entry() and fence_entry()
 855 // until initialization is complete.
 856 // TODO - replace with .il implementation when compiler supports it.
 857 
 858 typedef int32_t  xchg_func_t        (int32_t,  volatile int32_t*);
 859 typedef int32_t  cmpxchg_func_t     (int32_t,  volatile int32_t*,  int32_t);
 860 typedef int64_t  cmpxchg_long_func_t(int64_t,  volatile int64_t*,  int64_t);
 861 typedef int32_t  add_func_t         (int32_t,  volatile int32_t*);
 862 
 863 int32_t os::atomic_xchg_bootstrap(int32_t exchange_value, volatile int32_t* dest) {
 864   // try to use the stub:
 865   xchg_func_t* func = CAST_TO_FN_PTR(xchg_func_t*, StubRoutines::atomic_xchg_entry());
 866 
 867   if (func != NULL) {
 868     os::atomic_xchg_func = func;
 869     return (*func)(exchange_value, dest);
 870   }
 871   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 872 
 873   int32_t old_value = *dest;
 874   *dest = exchange_value;
 875   return old_value;
 876 }
 877 
 878 int32_t os::atomic_cmpxchg_bootstrap(int32_t exchange_value, volatile int32_t* dest, int32_t compare_value) {
 879   // try to use the stub:
 880   cmpxchg_func_t* func = CAST_TO_FN_PTR(cmpxchg_func_t*, StubRoutines::atomic_cmpxchg_entry());
 881 
 882   if (func != NULL) {
 883     os::atomic_cmpxchg_func = func;
 884     return (*func)(exchange_value, dest, compare_value);
 885   }
 886   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 887 
 888   int32_t old_value = *dest;
 889   if (old_value == compare_value)
 890     *dest = exchange_value;
 891   return old_value;
 892 }
 893 
 894 int64_t os::atomic_cmpxchg_long_bootstrap(int64_t exchange_value, volatile int64_t* dest, int64_t compare_value) {
 895   // try to use the stub:
 896   cmpxchg_long_func_t* func = CAST_TO_FN_PTR(cmpxchg_long_func_t*, StubRoutines::atomic_cmpxchg_long_entry());
 897 
 898   if (func != NULL) {
 899     os::atomic_cmpxchg_long_func = func;
 900     return (*func)(exchange_value, dest, compare_value);
 901   }
 902   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 903 
 904   int64_t old_value = *dest;
 905   if (old_value == compare_value)
 906     *dest = exchange_value;
 907   return old_value;
 908 }
 909 
 910 int32_t os::atomic_add_bootstrap(int32_t add_value, volatile int32_t* dest) {
 911   // try to use the stub:
 912   add_func_t* func = CAST_TO_FN_PTR(add_func_t*, StubRoutines::atomic_add_entry());
 913 
 914   if (func != NULL) {
 915     os::atomic_add_func = func;
 916     return (*func)(add_value, dest);
 917   }
 918   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 919 
 920   return (*dest) += add_value;
 921 }
 922 
 923 xchg_func_t*         os::atomic_xchg_func         = os::atomic_xchg_bootstrap;
 924 cmpxchg_func_t*      os::atomic_cmpxchg_func      = os::atomic_cmpxchg_bootstrap;
 925 cmpxchg_long_func_t* os::atomic_cmpxchg_long_func = os::atomic_cmpxchg_long_bootstrap;
 926 add_func_t*          os::atomic_add_func          = os::atomic_add_bootstrap;
 927 
 928 extern "C" void _solaris_raw_setup_fpu(address ptr);
 929 void os::setup_fpu() {
 930   address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
 931   _solaris_raw_setup_fpu(fpu_cntrl);
 932 }
 933 #endif // AMD64
 934 
 935 #ifndef PRODUCT
 936 void os::verify_stack_alignment() {
 937 #ifdef AMD64
 938   assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
 939 #endif
 940 }
 941 #endif
 942 
 943 int os::extra_bang_size_in_bytes() {
 944   // JDK-8050147 requires the full cache line bang for x86.
 945   return VM_Version::L1_line_size();
 946 }