rev 12283 : 8169373: Work around linux NPTL stack guard error.
Summary: Also streamline OS guard page handling on linuxs390, linuxppc, aixppc.

   1 /*
   2  * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2012, 2016 SAP SE. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 // no precompiled headers
  27 #include "asm/assembler.inline.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 "jvm_linux.h"
  36 #include "memory/allocation.inline.hpp"
  37 #include "nativeInst_ppc.hpp"
  38 #include "os_share_linux.hpp"
  39 #include "prims/jniFastGetField.hpp"
  40 #include "prims/jvm.h"
  41 #include "prims/jvm_misc.hpp"
  42 #include "runtime/arguments.hpp"
  43 #include "runtime/extendedPC.hpp"
  44 #include "runtime/frame.inline.hpp"
  45 #include "runtime/interfaceSupport.hpp"
  46 #include "runtime/java.hpp"
  47 #include "runtime/javaCalls.hpp"
  48 #include "runtime/mutexLocker.hpp"
  49 #include "runtime/osThread.hpp"
  50 #include "runtime/sharedRuntime.hpp"
  51 #include "runtime/stubRoutines.hpp"
  52 #include "runtime/thread.inline.hpp"
  53 #include "runtime/timer.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 <errno.h>
  63 # include <dlfcn.h>
  64 # include <stdlib.h>
  65 # include <stdio.h>
  66 # include <unistd.h>
  67 # include <sys/resource.h>
  68 # include <pthread.h>
  69 # include <sys/stat.h>
  70 # include <sys/time.h>
  71 # include <sys/utsname.h>
  72 # include <sys/socket.h>
  73 # include <sys/wait.h>
  74 # include <pwd.h>
  75 # include <poll.h>
  76 # include <ucontext.h>
  77 
  78 
  79 address os::current_stack_pointer() {
  80   intptr_t* csp;
  81 
  82   // inline assembly `mr regno(csp), R1_SP':
  83   __asm__ __volatile__ ("mr %0, 1":"=r"(csp):);
  84 
  85   return (address) csp;
  86 }
  87 
  88 char* os::non_memory_address_word() {
  89   // Must never look like an address returned by reserve_memory,
  90   // even in its subfields (as defined by the CPU immediate fields,
  91   // if the CPU splits constants across multiple instructions).
  92 
  93   return (char*) -1;
  94 }
  95 
  96 void os::initialize_thread(Thread *thread) { }
  97 
  98 // Frame information (pc, sp, fp) retrieved via ucontext
  99 // always looks like a C-frame according to the frame
 100 // conventions in frame_ppc64.hpp.
 101 address os::Linux::ucontext_get_pc(const ucontext_t * uc) {
 102   // On powerpc64, ucontext_t is not selfcontained but contains
 103   // a pointer to an optional substructure (mcontext_t.regs) containing the volatile
 104   // registers - NIP, among others.
 105   // This substructure may or may not be there depending where uc came from:
 106   // - if uc was handed over as the argument to a sigaction handler, a pointer to the
 107   //   substructure was provided by the kernel when calling the signal handler, and
 108   //   regs->nip can be accessed.
 109   // - if uc was filled by getcontext(), it is undefined - getcontext() does not fill
 110   //   it because the volatile registers are not needed to make setcontext() work.
 111   //   Hopefully it was zero'd out beforehand.
 112   guarantee(uc->uc_mcontext.regs != NULL, "only use ucontext_get_pc in sigaction context");
 113   return (address)uc->uc_mcontext.regs->nip;
 114 }
 115 
 116 // modify PC in ucontext.
 117 // Note: Only use this for an ucontext handed down to a signal handler. See comment
 118 // in ucontext_get_pc.
 119 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
 120   guarantee(uc->uc_mcontext.regs != NULL, "only use ucontext_set_pc in sigaction context");
 121   uc->uc_mcontext.regs->nip = (unsigned long)pc;
 122 }
 123 
 124 intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) {
 125   return (intptr_t*)uc->uc_mcontext.regs->gpr[1/*REG_SP*/];
 126 }
 127 
 128 intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) {
 129   return NULL;
 130 }
 131 
 132 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
 133                     intptr_t** ret_sp, intptr_t** ret_fp) {
 134 
 135   ExtendedPC  epc;
 136   const ucontext_t* uc = (const ucontext_t*)ucVoid;
 137 
 138   if (uc != NULL) {
 139     epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
 140     if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
 141     if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
 142   } else {
 143     // construct empty ExtendedPC for return value checking
 144     epc = ExtendedPC(NULL);
 145     if (ret_sp) *ret_sp = (intptr_t *)NULL;
 146     if (ret_fp) *ret_fp = (intptr_t *)NULL;
 147   }
 148 
 149   return epc;
 150 }
 151 
 152 frame os::fetch_frame_from_context(const void* ucVoid) {
 153   intptr_t* sp;
 154   intptr_t* fp;
 155   ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
 156   return frame(sp, epc.pc());
 157 }
 158 
 159 bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
 160   address pc = (address) os::Linux::ucontext_get_pc(uc);
 161   if (Interpreter::contains(pc)) {
 162     // Interpreter performs stack banging after the fixed frame header has
 163     // been generated while the compilers perform it before. To maintain
 164     // semantic consistency between interpreted and compiled frames, the
 165     // method returns the Java sender of the current frame.
 166     *fr = os::fetch_frame_from_context(uc);
 167     if (!fr->is_first_java_frame()) {
 168       assert(fr->safe_for_sender(thread), "Safety check");
 169       *fr = fr->java_sender();
 170     }
 171   } else {
 172     // More complex code with compiled code.
 173     assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
 174     CodeBlob* cb = CodeCache::find_blob(pc);
 175     if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
 176       // Not sure where the pc points to, fallback to default
 177       // stack overflow handling. In compiled code, we bang before
 178       // the frame is complete.
 179       return false;
 180     } else {
 181       intptr_t* fp = os::Linux::ucontext_get_fp(uc);
 182       intptr_t* sp = os::Linux::ucontext_get_sp(uc);
 183       *fr = frame(sp, (address)*sp);
 184       if (!fr->is_java_frame()) {
 185         assert(fr->safe_for_sender(thread), "Safety check");
 186         assert(!fr->is_first_frame(), "Safety check");
 187         *fr = fr->java_sender();
 188       }
 189     }
 190   }
 191   assert(fr->is_java_frame(), "Safety check");
 192   return true;
 193 }
 194 
 195 frame os::get_sender_for_C_frame(frame* fr) {
 196   if (*fr->sp() == 0) {
 197     // fr is the last C frame
 198     return frame(NULL, NULL);
 199   }
 200   return frame(fr->sender_sp(), fr->sender_pc());
 201 }
 202 
 203 
 204 frame os::current_frame() {
 205   intptr_t* csp = (intptr_t*) *((intptr_t*) os::current_stack_pointer());
 206   // hack.
 207   frame topframe(csp, (address)0x8);
 208   // Return sender of sender of current topframe which hopefully
 209   // both have pc != NULL.
 210   frame tmp = os::get_sender_for_C_frame(&topframe);
 211   return os::get_sender_for_C_frame(&tmp);
 212 }
 213 
 214 // Utility functions
 215 
 216 extern "C" JNIEXPORT int
 217 JVM_handle_linux_signal(int sig,
 218                         siginfo_t* info,
 219                         void* ucVoid,
 220                         int abort_if_unrecognized) {
 221   ucontext_t* uc = (ucontext_t*) ucVoid;
 222 
 223   Thread* t = Thread::current_or_null_safe();
 224 
 225   SignalHandlerMark shm(t);
 226 
 227   // Note: it's not uncommon that JNI code uses signal/sigset to install
 228   // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
 229   // or have a SIGILL handler when detecting CPU type). When that happens,
 230   // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
 231   // avoid unnecessary crash when libjsig is not preloaded, try handle signals
 232   // that do not require siginfo/ucontext first.
 233 
 234   if (sig == SIGPIPE) {
 235     if (os::Linux::chained_handler(sig, info, ucVoid)) {
 236       return true;
 237     } else {
 238       // Ignoring SIGPIPE - see bugs 4229104
 239       return true;
 240     }
 241   }
 242 
 243   // Make the signal handler transaction-aware by checking the existence of a
 244   // second (transactional) context with MSR TS bits active. If the signal is
 245   // caught during a transaction, then just return to the HTM abort handler.
 246   // Please refer to Linux kernel document powerpc/transactional_memory.txt,
 247   // section "Signals".
 248   if (uc && uc->uc_link) {
 249     ucontext_t* second_uc = uc->uc_link;
 250 
 251     // MSR TS bits are 29 and 30 (Power ISA, v2.07B, Book III-S, pp. 857-858,
 252     // 3.2.1 "Machine State Register"), however note that ISA notation for bit
 253     // numbering is MSB 0, so for normal bit numbering (LSB 0) they come to be
 254     // bits 33 and 34. It's not related to endianness, just a notation matter.
 255     if (second_uc->uc_mcontext.regs->msr & 0x600000000) {
 256       if (TraceTraps) {
 257         tty->print_cr("caught signal in transaction, "
 258                         "ignoring to jump to abort handler");
 259       }
 260       // Return control to the HTM abort handler.
 261       return true;
 262     }
 263   }
 264 
 265   JavaThread* thread = NULL;
 266   VMThread* vmthread = NULL;
 267   if (os::Linux::signal_handlers_are_installed) {
 268     if (t != NULL) {
 269       if(t->is_Java_thread()) {
 270         thread = (JavaThread*)t;
 271       } else if(t->is_VM_thread()) {
 272         vmthread = (VMThread *)t;
 273       }
 274     }
 275   }
 276 
 277   // Moved SafeFetch32 handling outside thread!=NULL conditional block to make
 278   // it work if no associated JavaThread object exists.
 279   if (uc) {
 280     address const pc = os::Linux::ucontext_get_pc(uc);
 281     if (pc && StubRoutines::is_safefetch_fault(pc)) {
 282       os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
 283       return true;
 284     }
 285   }
 286 
 287   // decide if this trap can be handled by a stub
 288   address stub = NULL;
 289   address pc   = NULL;
 290 
 291   //%note os_trap_1
 292   if (info != NULL && uc != NULL && thread != NULL) {
 293     pc = (address) os::Linux::ucontext_get_pc(uc);
 294 
 295     // Handle ALL stack overflow variations here
 296     if (sig == SIGSEGV) {
 297       // Si_addr may not be valid due to a bug in the linux-ppc64 kernel (see
 298       // comment below). Use get_stack_bang_address instead of si_addr.
 299       address addr = ((NativeInstruction*)pc)->get_stack_bang_address(uc);
 300 
 301       // Check if fault address is within thread stack.
 302       if (thread->on_local_stack(addr)) {
 303         // stack overflow
 304         if (thread->in_stack_yellow_reserved_zone(addr)) {
 305           if (thread->thread_state() == _thread_in_Java) {
 306             if (thread->in_stack_reserved_zone(addr)) {
 307               frame fr;
 308               if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) {
 309                 assert(fr.is_java_frame(), "Must be a Javac frame");
 310                 frame activation =
 311                   SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
 312                 if (activation.sp() != NULL) {
 313                   thread->disable_stack_reserved_zone();
 314                   if (activation.is_interpreted_frame()) {
 315                     thread->set_reserved_stack_activation((address)activation.fp());
 316                   } else {
 317                     thread->set_reserved_stack_activation((address)activation.unextended_sp());
 318                   }
 319                   return 1;
 320                 }
 321               }
 322             }
 323             // Throw a stack overflow exception.
 324             // Guard pages will be reenabled while unwinding the stack.
 325             thread->disable_stack_yellow_reserved_zone();
 326             stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
 327           } else {
 328             // Thread was in the vm or native code. Return and try to finish.
 329             thread->disable_stack_yellow_reserved_zone();
 330             return 1;
 331           }
 332         } else if (thread->in_stack_red_zone(addr)) {
 333           // Fatal red zone violation.  Disable the guard pages and fall through
 334           // to handle_unexpected_exception way down below.
 335           thread->disable_stack_red_zone();
 336           tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
 337 
 338           // This is a likely cause, but hard to verify. Let's just print
 339           // it as a hint.
 340           tty->print_raw_cr("Please check if any of your loaded .so files has "
 341                             "enabled executable stack (see man page execstack(8))");
 342         } else {
 343           // Accessing stack address below sp may cause SEGV if current
 344           // thread has MAP_GROWSDOWN stack. This should only happen when
 345           // current thread was created by user code with MAP_GROWSDOWN flag
 346           // and then attached to VM. See notes in os_linux.cpp.
 347           if (thread->osthread()->expanding_stack() == 0) {
 348              thread->osthread()->set_expanding_stack();
 349              if (os::Linux::manually_expand_stack(thread, addr)) {
 350                thread->osthread()->clear_expanding_stack();
 351                return 1;
 352              }
 353              thread->osthread()->clear_expanding_stack();
 354           } else {
 355              fatal("recursive segv. expanding stack.");
 356           }
 357         }
 358       }
 359     }
 360 
 361     if (thread->thread_state() == _thread_in_Java) {
 362       // Java thread running in Java code => find exception handler if any
 363       // a fault inside compiled code, the interpreter, or a stub
 364 
 365       // A VM-related SIGILL may only occur if we are not in the zero page.
 366       // On AIX, we get a SIGILL if we jump to 0x0 or to somewhere else
 367       // in the zero page, because it is filled with 0x0. We ignore
 368       // explicit SIGILLs in the zero page.
 369       if (sig == SIGILL && (pc < (address) 0x200)) {
 370         if (TraceTraps) {
 371           tty->print_raw_cr("SIGILL happened inside zero page.");
 372         }
 373         goto report_and_die;
 374       }
 375 
 376       CodeBlob *cb = NULL;
 377       // Handle signal from NativeJump::patch_verified_entry().
 378       if (( TrapBasedNotEntrantChecks && sig == SIGTRAP && nativeInstruction_at(pc)->is_sigtrap_zombie_not_entrant()) ||
 379           (!TrapBasedNotEntrantChecks && sig == SIGILL  && nativeInstruction_at(pc)->is_sigill_zombie_not_entrant())) {
 380         if (TraceTraps) {
 381           tty->print_cr("trap: zombie_not_entrant (%s)", (sig == SIGTRAP) ? "SIGTRAP" : "SIGILL");
 382         }
 383         stub = SharedRuntime::get_handle_wrong_method_stub();
 384       }
 385 
 386       else if (sig == SIGSEGV &&
 387                // A linux-ppc64 kernel before 2.6.6 doesn't set si_addr on some segfaults
 388                // in 64bit mode (cf. http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.6),
 389                // especially when we try to read from the safepoint polling page. So the check
 390                //   (address)info->si_addr == os::get_standard_polling_page()
 391                // doesn't work for us. We use:
 392                ((NativeInstruction*)pc)->is_safepoint_poll() &&
 393                CodeCache::contains((void*) pc) &&
 394                ((cb = CodeCache::find_blob(pc)) != NULL) &&
 395                cb->is_compiled()) {
 396         if (TraceTraps) {
 397           tty->print_cr("trap: safepoint_poll at " INTPTR_FORMAT " (SIGSEGV)", p2i(pc));
 398         }
 399         stub = SharedRuntime::get_poll_stub(pc);
 400       }
 401 
 402       // SIGTRAP-based ic miss check in compiled code.
 403       else if (sig == SIGTRAP && TrapBasedICMissChecks &&
 404                nativeInstruction_at(pc)->is_sigtrap_ic_miss_check()) {
 405         if (TraceTraps) {
 406           tty->print_cr("trap: ic_miss_check at " INTPTR_FORMAT " (SIGTRAP)", p2i(pc));
 407         }
 408         stub = SharedRuntime::get_ic_miss_stub();
 409       }
 410 
 411       // SIGTRAP-based implicit null check in compiled code.
 412       else if (sig == SIGTRAP && TrapBasedNullChecks &&
 413                nativeInstruction_at(pc)->is_sigtrap_null_check()) {
 414         if (TraceTraps) {
 415           tty->print_cr("trap: null_check at " INTPTR_FORMAT " (SIGTRAP)", p2i(pc));
 416         }
 417         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
 418       }
 419 
 420       // SIGSEGV-based implicit null check in compiled code.
 421       else if (sig == SIGSEGV && ImplicitNullChecks &&
 422                CodeCache::contains((void*) pc) &&
 423                !MacroAssembler::needs_explicit_null_check((intptr_t) info->si_addr)) {
 424         if (TraceTraps) {
 425           tty->print_cr("trap: null_check at " INTPTR_FORMAT " (SIGSEGV)", p2i(pc));
 426         }
 427         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
 428       }
 429 
 430 #ifdef COMPILER2
 431       // SIGTRAP-based implicit range check in compiled code.
 432       else if (sig == SIGTRAP && TrapBasedRangeChecks &&
 433                nativeInstruction_at(pc)->is_sigtrap_range_check()) {
 434         if (TraceTraps) {
 435           tty->print_cr("trap: range_check at " INTPTR_FORMAT " (SIGTRAP)", p2i(pc));
 436         }
 437         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
 438       }
 439 #endif
 440       else if (sig == SIGBUS) {
 441         // BugId 4454115: A read from a MappedByteBuffer can fault here if the
 442         // underlying file has been truncated. Do not crash the VM in such a case.
 443         CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
 444         CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
 445         if (nm != NULL && nm->has_unsafe_access()) {
 446           address next_pc = pc + 4;
 447           next_pc = SharedRuntime::handle_unsafe_access(thread, next_pc);
 448           os::Linux::ucontext_set_pc(uc, next_pc);
 449           return true;
 450         }
 451       }
 452     }
 453 
 454     else { // thread->thread_state() != _thread_in_Java
 455       if (sig == SIGILL && VM_Version::is_determine_features_test_running()) {
 456         // SIGILL must be caused by VM_Version::determine_features().
 457         *(int *)pc = 0; // patch instruction to 0 to indicate that it causes a SIGILL,
 458                         // flushing of icache is not necessary.
 459         stub = pc + 4;  // continue with next instruction.
 460       }
 461       else if (thread->thread_state() == _thread_in_vm &&
 462                sig == SIGBUS && thread->doing_unsafe_access()) {
 463         address next_pc = pc + 4;
 464         next_pc = SharedRuntime::handle_unsafe_access(thread, next_pc);
 465         os::Linux::ucontext_set_pc(uc, pc + 4);
 466         return true;
 467       }
 468     }
 469 
 470     // Check to see if we caught the safepoint code in the
 471     // process of write protecting the memory serialization page.
 472     // It write enables the page immediately after protecting it
 473     // so we can just return to retry the write.
 474     if ((sig == SIGSEGV) &&
 475         // Si_addr may not be valid due to a bug in the linux-ppc64 kernel (see comment above).
 476         // Use is_memory_serialization instead of si_addr.
 477         ((NativeInstruction*)pc)->is_memory_serialization(thread, ucVoid)) {
 478       // Synchronization problem in the pseudo memory barrier code (bug id 6546278)
 479       // Block current thread until the memory serialize page permission restored.
 480       os::block_on_serialize_page_trap();
 481       return true;
 482     }
 483   }
 484 
 485   if (stub != NULL) {
 486     // Save all thread context in case we need to restore it.
 487     if (thread != NULL) thread->set_saved_exception_pc(pc);
 488     os::Linux::ucontext_set_pc(uc, stub);
 489     return true;
 490   }
 491 
 492   // signal-chaining
 493   if (os::Linux::chained_handler(sig, info, ucVoid)) {
 494     return true;
 495   }
 496 
 497   if (!abort_if_unrecognized) {
 498     // caller wants another chance, so give it to him
 499     return false;
 500   }
 501 
 502   if (pc == NULL && uc != NULL) {
 503     pc = os::Linux::ucontext_get_pc(uc);
 504   }
 505 
 506 report_and_die:
 507   // unmask current signal
 508   sigset_t newset;
 509   sigemptyset(&newset);
 510   sigaddset(&newset, sig);
 511   sigprocmask(SIG_UNBLOCK, &newset, NULL);
 512 
 513   VMError::report_and_die(t, sig, pc, info, ucVoid);
 514 
 515   ShouldNotReachHere();
 516   return false;
 517 }
 518 
 519 void os::Linux::init_thread_fpu_state(void) {
 520   // Disable FP exceptions.
 521   __asm__ __volatile__ ("mtfsfi 6,0");
 522 }
 523 
 524 int os::Linux::get_fpu_control_word(void) {
 525   // x86 has problems with FPU precision after pthread_cond_timedwait().
 526   // nothing to do on ppc64.
 527   return 0;
 528 }
 529 
 530 void os::Linux::set_fpu_control_word(int fpu_control) {
 531   // x86 has problems with FPU precision after pthread_cond_timedwait().
 532   // nothing to do on ppc64.
 533 }
 534 
 535 ////////////////////////////////////////////////////////////////////////////////
 536 // thread stack
 537 
 538 size_t os::Posix::_compiler_thread_min_stack_allowed = 128 * K;


 539 size_t os::Posix::_java_thread_min_stack_allowed = 128 * K;
 540 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 128 * K;
 541 
 542 // return default stack size for thr_type
 543 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
 544   // default stack size (compiler thread needs larger stack)
 545   size_t s = (thr_type == os::compiler_thread ? 4 * M : 1024 * K);
 546   return s;
 547 }
 548 
 549 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
 550   return 2 * page_size();


 551 }
 552 
 553 // Java thread:
 554 //
 555 //   Low memory addresses
 556 //    +------------------------+
 557 //    |                        |\  JavaThread created by VM does not have glibc
 558 //    |    glibc guard page    | - guard, attached Java thread usually has
 559 //    |                        |/  1 page glibc guard.
 560 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
 561 //    |                        |\
 562 //    |  HotSpot Guard Pages   | - red and yellow pages
 563 //    |                        |/
 564 //    +------------------------+ JavaThread::stack_yellow_zone_base()
 565 //    |                        |\
 566 //    |      Normal Stack      | -
 567 //    |                        |/
 568 // P2 +------------------------+ Thread::stack_base()
 569 //
 570 // Non-Java thread:
 571 //
 572 //   Low memory addresses
 573 //    +------------------------+
 574 //    |                        |\
 575 //    |  glibc guard page      | - usually 1 page
 576 //    |                        |/
 577 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
 578 //    |                        |\
 579 //    |      Normal Stack      | -
 580 //    |                        |/
 581 // P2 +------------------------+ Thread::stack_base()
 582 //
 583 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
 584 //    pthread_attr_getstack()
 585 
 586 static void current_stack_region(address * bottom, size_t * size) {
 587   if (os::Linux::is_initial_thread()) {
 588      // initial thread needs special handling because pthread_getattr_np()
 589      // may return bogus value.
 590     *bottom = os::Linux::initial_thread_stack_bottom();
 591     *size   = os::Linux::initial_thread_stack_size();
 592   } else {
 593     pthread_attr_t attr;
 594 
 595     int rslt = pthread_getattr_np(pthread_self(), &attr);
 596 
 597     // JVM needs to know exact stack location, abort if it fails
 598     if (rslt != 0) {
 599       if (rslt == ENOMEM) {
 600         vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
 601       } else {
 602         fatal("pthread_getattr_np failed with errno = %d", rslt);
 603       }
 604     }
 605 
 606     if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
 607       fatal("Can not locate current stack attributes!");
 608     }
 609 
 610     pthread_attr_destroy(&attr);
 611 
 612   }
 613   assert(os::current_stack_pointer() >= *bottom &&
 614          os::current_stack_pointer() < *bottom + *size, "just checking");
 615 }
 616 
 617 address os::current_stack_base() {
 618   address bottom;
 619   size_t size;
 620   current_stack_region(&bottom, &size);
 621   return (bottom + size);
 622 }
 623 
 624 size_t os::current_stack_size() {
 625   // stack size includes normal stack and HotSpot guard pages
 626   address bottom;
 627   size_t size;
 628   current_stack_region(&bottom, &size);
 629   return size;
 630 }
 631 
 632 /////////////////////////////////////////////////////////////////////////////
 633 // helper functions for fatal error handler
 634 
 635 void os::print_context(outputStream *st, const void *context) {
 636   if (context == NULL) return;
 637 
 638   const ucontext_t* uc = (const ucontext_t*)context;
 639 
 640   st->print_cr("Registers:");
 641   st->print("pc =" INTPTR_FORMAT "  ", uc->uc_mcontext.regs->nip);
 642   st->print("lr =" INTPTR_FORMAT "  ", uc->uc_mcontext.regs->link);
 643   st->print("ctr=" INTPTR_FORMAT "  ", uc->uc_mcontext.regs->ctr);
 644   st->cr();
 645   for (int i = 0; i < 32; i++) {
 646     st->print("r%-2d=" INTPTR_FORMAT "  ", i, uc->uc_mcontext.regs->gpr[i]);
 647     if (i % 3 == 2) st->cr();
 648   }
 649   st->cr();
 650   st->cr();
 651 
 652   intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
 653   st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp));
 654   print_hex_dump(st, (address)sp, (address)(sp + 128), sizeof(intptr_t));
 655   st->cr();
 656 
 657   // Note: it may be unsafe to inspect memory near pc. For example, pc may
 658   // point to garbage if entry point in an nmethod is corrupted. Leave
 659   // this at the end, and hope for the best.
 660   address pc = os::Linux::ucontext_get_pc(uc);
 661   st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc));
 662   print_hex_dump(st, pc - 64, pc + 64, /*instrsize=*/4);
 663   st->cr();
 664 }
 665 
 666 void os::print_register_info(outputStream *st, const void *context) {
 667   if (context == NULL) return;
 668 
 669   const ucontext_t *uc = (const ucontext_t*)context;
 670 
 671   st->print_cr("Register to memory mapping:");
 672   st->cr();
 673 
 674   // this is only for the "general purpose" registers
 675   for (int i = 0; i < 32; i++) {
 676     st->print("r%-2d=", i);
 677     print_location(st, uc->uc_mcontext.regs->gpr[i]);
 678   }
 679   st->cr();
 680 }
 681 
 682 extern "C" {
 683   int SpinPause() {
 684     return 0;
 685   }
 686 }
 687 
 688 #ifndef PRODUCT
 689 void os::verify_stack_alignment() {
 690   assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
 691 }
 692 #endif
 693 
 694 int os::extra_bang_size_in_bytes() {
 695   // PPC does not require the additional stack bang.
 696   return 0;
 697 }
--- EOF ---