1 /*
   2  * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright 2007, 2008, 2009, 2010 Red Hat, Inc.
   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 "assembler_zero.inline.hpp"
  28 #include "classfile/classLoader.hpp"
  29 #include "classfile/systemDictionary.hpp"
  30 #include "classfile/vmSymbols.hpp"
  31 #include "code/icBuffer.hpp"
  32 #include "code/vtableStubs.hpp"
  33 #include "interpreter/interpreter.hpp"
  34 #include "jvm_linux.h"
  35 #include "memory/allocation.inline.hpp"
  36 #include "mutex_linux.inline.hpp"
  37 #include "nativeInst_zero.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/timer.hpp"
  53 #include "thread_linux.inline.hpp"
  54 #include "utilities/events.hpp"
  55 #include "utilities/vmError.hpp"
  56 #ifdef COMPILER1
  57 #include "c1/c1_Runtime1.hpp"
  58 #endif
  59 #ifdef COMPILER2
  60 #include "opto/runtime.hpp"
  61 #endif
  62 
  63 address os::current_stack_pointer() {
  64   address dummy = (address) &dummy;
  65   return dummy;
  66 }
  67 
  68 frame os::get_sender_for_C_frame(frame* fr) {
  69   ShouldNotCallThis();
  70 }
  71 
  72 frame os::current_frame() {
  73   // The only thing that calls this is the stack printing code in
  74   // VMError::report:
  75   //   - Step 110 (printing stack bounds) uses the sp in the frame
  76   //     to determine the amount of free space on the stack.  We
  77   //     set the sp to a close approximation of the real value in
  78   //     order to allow this step to complete.
  79   //   - Step 120 (printing native stack) tries to walk the stack.
  80   //     The frame we create has a NULL pc, which is ignored as an
  81   //     invalid frame.
  82   frame dummy = frame();
  83   dummy.set_sp((intptr_t *) current_stack_pointer());
  84   return dummy;
  85 }
  86 
  87 char* os::non_memory_address_word() {
  88   // Must never look like an address returned by reserve_memory,
  89   // even in its subfields (as defined by the CPU immediate fields,
  90   // if the CPU splits constants across multiple instructions).
  91 #ifdef SPARC
  92   // On SPARC, 0 != %hi(any real address), because there is no
  93   // allocation in the first 1Kb of the virtual address space.
  94   return (char *) 0;
  95 #else
  96   // This is the value for x86; works pretty well for PPC too.
  97   return (char *) -1;
  98 #endif // SPARC
  99 }
 100 
 101 void os::initialize_thread(Thread * thr){
 102   // Nothing to do.
 103 }
 104 
 105 address os::Linux::ucontext_get_pc(ucontext_t* uc) {
 106   ShouldNotCallThis();
 107 }
 108 
 109 ExtendedPC os::fetch_frame_from_context(void* ucVoid,
 110                                         intptr_t** ret_sp,
 111                                         intptr_t** ret_fp) {
 112   ShouldNotCallThis();
 113 }
 114 
 115 frame os::fetch_frame_from_context(void* ucVoid) {
 116   ShouldNotCallThis();
 117 }
 118 
 119 extern "C" JNIEXPORT int
 120 JVM_handle_linux_signal(int sig,
 121                         siginfo_t* info,
 122                         void* ucVoid,
 123                         int abort_if_unrecognized) {
 124   ucontext_t* uc = (ucontext_t*) ucVoid;
 125 
 126   Thread* t = ThreadLocalStorage::get_thread_slow();
 127 
 128   SignalHandlerMark shm(t);
 129 
 130   // Note: it's not uncommon that JNI code uses signal/sigset to
 131   // install then restore certain signal handler (e.g. to temporarily
 132   // block SIGPIPE, or have a SIGILL handler when detecting CPU
 133   // type). When that happens, JVM_handle_linux_signal() might be
 134   // invoked with junk info/ucVoid. To avoid unnecessary crash when
 135   // libjsig is not preloaded, try handle signals that do not require
 136   // siginfo/ucontext first.
 137 
 138   if (sig == SIGPIPE || sig == SIGXFSZ) {
 139     // allow chained handler to go first
 140     if (os::Linux::chained_handler(sig, info, ucVoid)) {
 141       return true;
 142     } else {
 143       if (PrintMiscellaneous && (WizardMode || Verbose)) {
 144         char buf[64];
 145         warning("Ignoring %s - see bugs 4229104 or 646499219",
 146                 os::exception_name(sig, buf, sizeof(buf)));
 147       }
 148       return true;
 149     }
 150   }
 151 
 152   JavaThread* thread = NULL;
 153   VMThread* vmthread = NULL;
 154   if (os::Linux::signal_handlers_are_installed) {
 155     if (t != NULL ){
 156       if(t->is_Java_thread()) {
 157         thread = (JavaThread*)t;
 158       }
 159       else if(t->is_VM_thread()){
 160         vmthread = (VMThread *)t;
 161       }
 162     }
 163   }
 164 
 165   if (info != NULL && thread != NULL) {
 166     // Handle ALL stack overflow variations here
 167     if (sig == SIGSEGV) {
 168       address addr = (address) info->si_addr;
 169 
 170       // check if fault address is within thread stack
 171       if (addr < thread->stack_base() &&
 172           addr >= thread->stack_base() - thread->stack_size()) {
 173         // stack overflow
 174         if (thread->in_stack_yellow_zone(addr)) {
 175           thread->disable_stack_yellow_zone();
 176           ShouldNotCallThis();
 177         }
 178         else if (thread->in_stack_red_zone(addr)) {
 179           thread->disable_stack_red_zone();
 180           ShouldNotCallThis();
 181         }
 182         else {
 183           // Accessing stack address below sp may cause SEGV if
 184           // current thread has MAP_GROWSDOWN stack. This should
 185           // only happen when current thread was created by user
 186           // code with MAP_GROWSDOWN flag and then attached to VM.
 187           // See notes in os_linux.cpp.
 188           if (thread->osthread()->expanding_stack() == 0) {
 189             thread->osthread()->set_expanding_stack();
 190             if (os::Linux::manually_expand_stack(thread, addr)) {
 191               thread->osthread()->clear_expanding_stack();
 192               return true;
 193             }
 194             thread->osthread()->clear_expanding_stack();
 195           }
 196           else {
 197             fatal("recursive segv. expanding stack.");
 198           }
 199         }
 200       }
 201     }
 202 
 203     /*if (thread->thread_state() == _thread_in_Java) {
 204       ShouldNotCallThis();
 205     }
 206     else*/ if (thread->thread_state() == _thread_in_vm &&
 207                sig == SIGBUS && thread->doing_unsafe_access()) {
 208       ShouldNotCallThis();
 209     }
 210 
 211     // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC
 212     // kicks in and the heap gets shrunk before the field access.
 213     /*if (sig == SIGSEGV || sig == SIGBUS) {
 214       address addr = JNI_FastGetField::find_slowcase_pc(pc);
 215       if (addr != (address)-1) {
 216         stub = addr;
 217       }
 218     }*/
 219 
 220     // Check to see if we caught the safepoint code in the process
 221     // of write protecting the memory serialization page.  It write
 222     // enables the page immediately after protecting it so we can
 223     // just return to retry the write.
 224     if (sig == SIGSEGV &&
 225         os::is_memory_serialize_page(thread, (address) info->si_addr)) {
 226       // Block current thread until permission is restored.
 227       os::block_on_serialize_page_trap();
 228       return true;
 229     }
 230   }
 231 
 232   // signal-chaining
 233   if (os::Linux::chained_handler(sig, info, ucVoid)) {
 234      return true;
 235   }
 236 
 237   if (!abort_if_unrecognized) {
 238     // caller wants another chance, so give it to him
 239     return false;
 240   }
 241 
 242 #ifndef PRODUCT
 243   if (sig == SIGSEGV) {
 244     fatal("\n#"
 245           "\n#    /--------------------\\"
 246           "\n#    | segmentation fault |"
 247           "\n#    \\---\\ /--------------/"
 248           "\n#        /"
 249           "\n#    [-]        |\\_/|    "
 250           "\n#    (+)=C      |o o|__  "
 251           "\n#    | |        =-*-=__\\ "
 252           "\n#    OOO        c_c_(___)");
 253   }
 254 #endif // !PRODUCT
 255 
 256   const char *fmt = "caught unhandled signal %d";
 257   char buf[64];
 258 
 259   sprintf(buf, fmt, sig);
 260   fatal(buf);
 261 }
 262 
 263 void os::Linux::init_thread_fpu_state(void) {
 264   // Nothing to do
 265 }
 266 
 267 int os::Linux::get_fpu_control_word() {
 268   ShouldNotCallThis();
 269 }
 270 
 271 void os::Linux::set_fpu_control_word(int fpu) {
 272   ShouldNotCallThis();
 273 }
 274 
 275 bool os::is_allocatable(size_t bytes) {
 276 #ifdef _LP64
 277   return true;
 278 #else
 279   if (bytes < 2 * G) {
 280     return true;
 281   }
 282 
 283   char* addr = reserve_memory(bytes, NULL);
 284 
 285   if (addr != NULL) {
 286     release_memory(addr, bytes);
 287   }
 288 
 289   return addr != NULL;
 290 #endif // _LP64
 291 }
 292 
 293 ///////////////////////////////////////////////////////////////////////////////
 294 // thread stack
 295 
 296 size_t os::Linux::min_stack_allowed = 64 * K;
 297 
 298 bool os::Linux::supports_variable_stack_size() {
 299   return true;
 300 }
 301 
 302 size_t os::Linux::default_stack_size(os::ThreadType thr_type) {
 303 #ifdef _LP64
 304   size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
 305 #else
 306   size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
 307 #endif // _LP64
 308   return s;
 309 }
 310 
 311 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
 312   // Only enable glibc guard pages for non-Java threads
 313   // (Java threads have HotSpot guard pages)
 314   return (thr_type == java_thread ? 0 : page_size());
 315 }
 316 
 317 static void current_stack_region(address *bottom, size_t *size) {
 318   pthread_attr_t attr;
 319   int res = pthread_getattr_np(pthread_self(), &attr);
 320   if (res != 0) {
 321     if (res == ENOMEM) {
 322       vm_exit_out_of_memory(0, "pthread_getattr_np");
 323     }
 324     else {
 325       fatal(err_msg("pthread_getattr_np failed with errno = %d", res));
 326     }
 327   }
 328 
 329   address stack_bottom;
 330   size_t stack_bytes;
 331   res = pthread_attr_getstack(&attr, (void **) &stack_bottom, &stack_bytes);
 332   if (res != 0) {
 333     fatal(err_msg("pthread_attr_getstack failed with errno = %d", res));
 334   }
 335   address stack_top = stack_bottom + stack_bytes;
 336 
 337   // The block of memory returned by pthread_attr_getstack() includes
 338   // guard pages where present.  We need to trim these off.
 339   size_t page_bytes = os::Linux::page_size();
 340   assert(((intptr_t) stack_bottom & (page_bytes - 1)) == 0, "unaligned stack");
 341 
 342   size_t guard_bytes;
 343   res = pthread_attr_getguardsize(&attr, &guard_bytes);
 344   if (res != 0) {
 345     fatal(err_msg("pthread_attr_getguardsize failed with errno = %d", res));
 346   }
 347   int guard_pages = align_size_up(guard_bytes, page_bytes) / page_bytes;
 348   assert(guard_bytes == guard_pages * page_bytes, "unaligned guard");
 349 
 350 #ifdef IA64
 351   // IA64 has two stacks sharing the same area of memory, a normal
 352   // stack growing downwards and a register stack growing upwards.
 353   // Guard pages, if present, are in the centre.  This code splits
 354   // the stack in two even without guard pages, though in theory
 355   // there's nothing to stop us allocating more to the normal stack
 356   // or more to the register stack if one or the other were found
 357   // to grow faster.
 358   int total_pages = align_size_down(stack_bytes, page_bytes) / page_bytes;
 359   stack_bottom += (total_pages - guard_pages) / 2 * page_bytes;
 360 #endif // IA64
 361 
 362   stack_bottom += guard_bytes;
 363 
 364   pthread_attr_destroy(&attr);
 365 
 366   // The initial thread has a growable stack, and the size reported
 367   // by pthread_attr_getstack is the maximum size it could possibly
 368   // be given what currently mapped.  This can be huge, so we cap it.
 369   if (os::Linux::is_initial_thread()) {
 370     stack_bytes = stack_top - stack_bottom;
 371 
 372     if (stack_bytes > JavaThread::stack_size_at_create())
 373       stack_bytes = JavaThread::stack_size_at_create();
 374 
 375     stack_bottom = stack_top - stack_bytes;
 376   }
 377 
 378   assert(os::current_stack_pointer() >= stack_bottom, "should do");
 379   assert(os::current_stack_pointer() < stack_top, "should do");
 380 
 381   *bottom = stack_bottom;
 382   *size = stack_top - stack_bottom;
 383 }
 384 
 385 address os::current_stack_base() {
 386   address bottom;
 387   size_t size;
 388   current_stack_region(&bottom, &size);
 389   return bottom + size;
 390 }
 391 
 392 size_t os::current_stack_size() {
 393   // stack size includes normal stack and HotSpot guard pages
 394   address bottom;
 395   size_t size;
 396   current_stack_region(&bottom, &size);
 397   return size;
 398 }
 399 
 400 /////////////////////////////////////////////////////////////////////////////
 401 // helper functions for fatal error handler
 402 
 403 void os::print_context(outputStream* st, void* context) {
 404   ShouldNotCallThis();
 405 }
 406 
 407 void os::print_register_info(outputStream *st, void *context) {
 408   ShouldNotCallThis();
 409 }
 410 
 411 /////////////////////////////////////////////////////////////////////////////
 412 // Stubs for things that would be in linux_zero.s if it existed.
 413 // You probably want to disassemble these monkeys to check they're ok.
 414 
 415 extern "C" {
 416   int SpinPause() {
 417   }
 418 
 419   int SafeFetch32(int *adr, int errValue) {
 420     int value = errValue;
 421     value = *adr;
 422     return value;
 423   }
 424   intptr_t SafeFetchN(intptr_t *adr, intptr_t errValue) {
 425     intptr_t value = errValue;
 426     value = *adr;
 427     return value;
 428   }
 429 
 430   void _Copy_conjoint_jshorts_atomic(jshort* from, jshort* to, size_t count) {
 431     if (from > to) {
 432       jshort *end = from + count;
 433       while (from < end)
 434         *(to++) = *(from++);
 435     }
 436     else if (from < to) {
 437       jshort *end = from;
 438       from += count - 1;
 439       to   += count - 1;
 440       while (from >= end)
 441         *(to--) = *(from--);
 442     }
 443   }
 444   void _Copy_conjoint_jints_atomic(jint* from, jint* to, size_t count) {
 445     if (from > to) {
 446       jint *end = from + count;
 447       while (from < end)
 448         *(to++) = *(from++);
 449     }
 450     else if (from < to) {
 451       jint *end = from;
 452       from += count - 1;
 453       to   += count - 1;
 454       while (from >= end)
 455         *(to--) = *(from--);
 456     }
 457   }
 458   void _Copy_conjoint_jlongs_atomic(jlong* from, jlong* to, size_t count) {
 459     if (from > to) {
 460       jlong *end = from + count;
 461       while (from < end)
 462         os::atomic_copy64(from++, to++);
 463     }
 464     else if (from < to) {
 465       jlong *end = from;
 466       from += count - 1;
 467       to   += count - 1;
 468       while (from >= end)
 469         os::atomic_copy64(from--, to--);
 470     }
 471   }
 472 
 473   void _Copy_arrayof_conjoint_bytes(HeapWord* from,
 474                                     HeapWord* to,
 475                                     size_t    count) {
 476     memmove(to, from, count);
 477   }
 478   void _Copy_arrayof_conjoint_jshorts(HeapWord* from,
 479                                       HeapWord* to,
 480                                       size_t    count) {
 481     memmove(to, from, count * 2);
 482   }
 483   void _Copy_arrayof_conjoint_jints(HeapWord* from,
 484                                     HeapWord* to,
 485                                     size_t    count) {
 486     memmove(to, from, count * 4);
 487   }
 488   void _Copy_arrayof_conjoint_jlongs(HeapWord* from,
 489                                      HeapWord* to,
 490                                      size_t    count) {
 491     memmove(to, from, count * 8);
 492   }
 493 };
 494 
 495 /////////////////////////////////////////////////////////////////////////////
 496 // Implementations of atomic operations not supported by processors.
 497 //  -- http://gcc.gnu.org/onlinedocs/gcc-4.2.1/gcc/Atomic-Builtins.html
 498 
 499 #ifndef _LP64
 500 extern "C" {
 501   long long unsigned int __sync_val_compare_and_swap_8(
 502     volatile void *ptr,
 503     long long unsigned int oldval,
 504     long long unsigned int newval) {
 505     ShouldNotCallThis();
 506   }
 507 };
 508 #endif // !_LP64
 509 
 510 #ifndef PRODUCT
 511 void os::verify_stack_alignment() {
 512 }
 513 #endif