1 /*
   2  * Copyright (c) 2003, 2015, 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/thread.inline.hpp"
  53 #include "runtime/timer.hpp"
  54 #include "utilities/events.hpp"
  55 #include "utilities/vmError.hpp"
  56 
  57 // See stubGenerator_zero.cpp
  58 #include <setjmp.h>
  59 extern sigjmp_buf* get_jmp_buf_for_continuation();
  60 
  61 address os::current_stack_pointer() {
  62   // return the address of the current function
  63   return (address)__builtin_frame_address(0);
  64 }
  65 
  66 frame os::get_sender_for_C_frame(frame* fr) {
  67   ShouldNotCallThis();
  68 }
  69 
  70 frame os::current_frame() {
  71   // The only thing that calls this is the stack printing code in
  72   // VMError::report:
  73   //   - Step 110 (printing stack bounds) uses the sp in the frame
  74   //     to determine the amount of free space on the stack.  We
  75   //     set the sp to a close approximation of the real value in
  76   //     order to allow this step to complete.
  77   //   - Step 120 (printing native stack) tries to walk the stack.
  78   //     The frame we create has a NULL pc, which is ignored as an
  79   //     invalid frame.
  80   frame dummy = frame();
  81   dummy.set_sp((intptr_t *) current_stack_pointer());
  82   return dummy;
  83 }
  84 
  85 char* os::non_memory_address_word() {
  86   // Must never look like an address returned by reserve_memory,
  87   // even in its subfields (as defined by the CPU immediate fields,
  88   // if the CPU splits constants across multiple instructions).
  89 #ifdef SPARC
  90   // On SPARC, 0 != %hi(any real address), because there is no
  91   // allocation in the first 1Kb of the virtual address space.
  92   return (char *) 0;
  93 #else
  94   // This is the value for x86; works pretty well for PPC too.
  95   return (char *) -1;
  96 #endif // SPARC
  97 }
  98 
  99 void os::initialize_thread(Thread * thr){
 100   // Nothing to do.
 101 }
 102 
 103 address os::Linux::ucontext_get_pc(ucontext_t* uc) {
 104   ShouldNotCallThis();
 105 }
 106 
 107 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
 108   ShouldNotCallThis();
 109 }
 110 
 111 ExtendedPC os::fetch_frame_from_context(void* ucVoid,
 112                                         intptr_t** ret_sp,
 113                                         intptr_t** ret_fp) {
 114   ShouldNotCallThis();
 115 }
 116 
 117 frame os::fetch_frame_from_context(void* ucVoid) {
 118   ShouldNotCallThis();
 119 }
 120 
 121 extern "C" JNIEXPORT int
 122 JVM_handle_linux_signal(int sig,
 123                         siginfo_t* info,
 124                         void* ucVoid,
 125                         int abort_if_unrecognized) {
 126   ucontext_t* uc = (ucontext_t*) ucVoid;
 127 
 128   Thread* t = ThreadLocalStorage::get_thread_slow();
 129 
 130   SignalHandlerMark shm(t);
 131 
 132   // handle SafeFetch faults
 133   if (sig == SIGSEGV || sig == SIGBUS) {
 134     sigjmp_buf* const pjb = get_jmp_buf_for_continuation();
 135     if (pjb) {
 136       siglongjmp(*pjb, 1);
 137     }
 138   }
 139 
 140   // Note: it's not uncommon that JNI code uses signal/sigset to
 141   // install then restore certain signal handler (e.g. to temporarily
 142   // block SIGPIPE, or have a SIGILL handler when detecting CPU
 143   // type). When that happens, JVM_handle_linux_signal() might be
 144   // invoked with junk info/ucVoid. To avoid unnecessary crash when
 145   // libjsig is not preloaded, try handle signals that do not require
 146   // siginfo/ucontext first.
 147 
 148   if (sig == SIGPIPE || sig == SIGXFSZ) {
 149     // allow chained handler to go first
 150     if (os::Linux::chained_handler(sig, info, ucVoid)) {
 151       return true;
 152     } else {
 153       if (PrintMiscellaneous && (WizardMode || Verbose)) {
 154         char buf[64];
 155         warning("Ignoring %s - see bugs 4229104 or 646499219",
 156                 os::exception_name(sig, buf, sizeof(buf)));
 157       }
 158       return true;
 159     }
 160   }
 161 
 162   JavaThread* thread = NULL;
 163   VMThread* vmthread = NULL;
 164   if (os::Linux::signal_handlers_are_installed) {
 165     if (t != NULL ){
 166       if(t->is_Java_thread()) {
 167         thread = (JavaThread*)t;
 168       }
 169       else if(t->is_VM_thread()){
 170         vmthread = (VMThread *)t;
 171       }
 172     }
 173   }
 174 
 175   if (info != NULL && thread != NULL) {
 176     // Handle ALL stack overflow variations here
 177     if (sig == SIGSEGV) {
 178       address addr = (address) info->si_addr;
 179 
 180       // check if fault address is within thread stack
 181       if (addr < thread->stack_base() &&
 182           addr >= thread->stack_base() - thread->stack_size()) {
 183         // stack overflow
 184         if (thread->in_stack_yellow_zone(addr)) {
 185           thread->disable_stack_yellow_zone();
 186           ShouldNotCallThis();
 187         }
 188         else if (thread->in_stack_red_zone(addr)) {
 189           thread->disable_stack_red_zone();
 190           ShouldNotCallThis();
 191         }
 192         else {
 193           // Accessing stack address below sp may cause SEGV if
 194           // current thread has MAP_GROWSDOWN stack. This should
 195           // only happen when current thread was created by user
 196           // code with MAP_GROWSDOWN flag and then attached to VM.
 197           // See notes in os_linux.cpp.
 198           if (thread->osthread()->expanding_stack() == 0) {
 199             thread->osthread()->set_expanding_stack();
 200             if (os::Linux::manually_expand_stack(thread, addr)) {
 201               thread->osthread()->clear_expanding_stack();
 202               return true;
 203             }
 204             thread->osthread()->clear_expanding_stack();
 205           }
 206           else {
 207             fatal("recursive segv. expanding stack.");
 208           }
 209         }
 210       }
 211     }
 212 
 213     /*if (thread->thread_state() == _thread_in_Java) {
 214       ShouldNotCallThis();
 215     }
 216     else*/ if (thread->thread_state() == _thread_in_vm &&
 217                sig == SIGBUS && thread->doing_unsafe_access()) {
 218       ShouldNotCallThis();
 219     }
 220 
 221     // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC
 222     // kicks in and the heap gets shrunk before the field access.
 223     /*if (sig == SIGSEGV || sig == SIGBUS) {
 224       address addr = JNI_FastGetField::find_slowcase_pc(pc);
 225       if (addr != (address)-1) {
 226         stub = addr;
 227       }
 228     }*/
 229 
 230     // Check to see if we caught the safepoint code in the process
 231     // of write protecting the memory serialization page.  It write
 232     // enables the page immediately after protecting it so we can
 233     // just return to retry the write.
 234     if (sig == SIGSEGV &&
 235         os::is_memory_serialize_page(thread, (address) info->si_addr)) {
 236       // Block current thread until permission is restored.
 237       os::block_on_serialize_page_trap();
 238       return true;
 239     }
 240   }
 241 
 242   // signal-chaining
 243   if (os::Linux::chained_handler(sig, info, ucVoid)) {
 244      return true;
 245   }
 246 
 247   if (!abort_if_unrecognized) {
 248     // caller wants another chance, so give it to him
 249     return false;
 250   }
 251 
 252 #ifndef PRODUCT
 253   if (sig == SIGSEGV) {
 254     fatal("\n#"
 255           "\n#    /--------------------\\"
 256           "\n#    | segmentation fault |"
 257           "\n#    \\---\\ /--------------/"
 258           "\n#        /"
 259           "\n#    [-]        |\\_/|    "
 260           "\n#    (+)=C      |o o|__  "
 261           "\n#    | |        =-*-=__\\ "
 262           "\n#    OOO        c_c_(___)");
 263   }
 264 #endif // !PRODUCT
 265 
 266   const char *fmt = "caught unhandled signal %d";
 267   char buf[64];
 268 
 269   sprintf(buf, fmt, sig);
 270   fatal(buf);
 271 }
 272 
 273 void os::Linux::init_thread_fpu_state(void) {
 274   // Nothing to do
 275 }
 276 
 277 int os::Linux::get_fpu_control_word() {
 278   ShouldNotCallThis();
 279 }
 280 
 281 void os::Linux::set_fpu_control_word(int fpu) {
 282   ShouldNotCallThis();
 283 }
 284 
 285 bool os::is_allocatable(size_t bytes) {
 286 #ifdef _LP64
 287   return true;
 288 #else
 289   if (bytes < 2 * G) {
 290     return true;
 291   }
 292 
 293   char* addr = reserve_memory(bytes, NULL);
 294 
 295   if (addr != NULL) {
 296     release_memory(addr, bytes);
 297   }
 298 
 299   return addr != NULL;
 300 #endif // _LP64
 301 }
 302 
 303 ///////////////////////////////////////////////////////////////////////////////
 304 // thread stack
 305 
 306 size_t os::Linux::min_stack_allowed = 64 * K;
 307 
 308 size_t os::Linux::default_stack_size(os::ThreadType thr_type) {
 309 #ifdef _LP64
 310   size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
 311 #else
 312   size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
 313 #endif // _LP64
 314   return s;
 315 }
 316 
 317 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
 318   // Only enable glibc guard pages for non-Java threads
 319   // (Java threads have HotSpot guard pages)
 320   return (thr_type == java_thread ? 0 : page_size());
 321 }
 322 
 323 static void current_stack_region(address *bottom, size_t *size) {
 324   pthread_attr_t attr;
 325   int res = pthread_getattr_np(pthread_self(), &attr);
 326   if (res != 0) {
 327     if (res == ENOMEM) {
 328       vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
 329     }
 330     else {
 331       fatal("pthread_getattr_np failed with errno = %d", res);
 332     }
 333   }
 334 
 335   address stack_bottom;
 336   size_t stack_bytes;
 337   res = pthread_attr_getstack(&attr, (void **) &stack_bottom, &stack_bytes);
 338   if (res != 0) {
 339     fatal("pthread_attr_getstack failed with errno = %d", res);
 340   }
 341   address stack_top = stack_bottom + stack_bytes;
 342 
 343   // The block of memory returned by pthread_attr_getstack() includes
 344   // guard pages where present.  We need to trim these off.
 345   size_t page_bytes = os::Linux::page_size();
 346   assert(((intptr_t) stack_bottom & (page_bytes - 1)) == 0, "unaligned stack");
 347 
 348   size_t guard_bytes;
 349   res = pthread_attr_getguardsize(&attr, &guard_bytes);
 350   if (res != 0) {
 351     fatal("pthread_attr_getguardsize failed with errno = %d", res);
 352   }
 353   int guard_pages = align_size_up(guard_bytes, page_bytes) / page_bytes;
 354   assert(guard_bytes == guard_pages * page_bytes, "unaligned guard");
 355 
 356 #ifdef IA64
 357   // IA64 has two stacks sharing the same area of memory, a normal
 358   // stack growing downwards and a register stack growing upwards.
 359   // Guard pages, if present, are in the centre.  This code splits
 360   // the stack in two even without guard pages, though in theory
 361   // there's nothing to stop us allocating more to the normal stack
 362   // or more to the register stack if one or the other were found
 363   // to grow faster.
 364   int total_pages = align_size_down(stack_bytes, page_bytes) / page_bytes;
 365   stack_bottom += (total_pages - guard_pages) / 2 * page_bytes;
 366 #endif // IA64
 367 
 368   stack_bottom += guard_bytes;
 369 
 370   pthread_attr_destroy(&attr);
 371 
 372   // The initial thread has a growable stack, and the size reported
 373   // by pthread_attr_getstack is the maximum size it could possibly
 374   // be given what currently mapped.  This can be huge, so we cap it.
 375   if (os::Linux::is_initial_thread()) {
 376     stack_bytes = stack_top - stack_bottom;
 377 
 378     if (stack_bytes > JavaThread::stack_size_at_create())
 379       stack_bytes = JavaThread::stack_size_at_create();
 380 
 381     stack_bottom = stack_top - stack_bytes;
 382   }
 383 
 384   assert(os::current_stack_pointer() >= stack_bottom, "should do");
 385   assert(os::current_stack_pointer() < stack_top, "should do");
 386 
 387   *bottom = stack_bottom;
 388   *size = stack_top - stack_bottom;
 389 }
 390 
 391 address os::current_stack_base() {
 392   address bottom;
 393   size_t size;
 394   current_stack_region(&bottom, &size);
 395   return bottom + size;
 396 }
 397 
 398 size_t os::current_stack_size() {
 399   // stack size includes normal stack and HotSpot guard pages
 400   address bottom;
 401   size_t size;
 402   current_stack_region(&bottom, &size);
 403   return size;
 404 }
 405 
 406 /////////////////////////////////////////////////////////////////////////////
 407 // helper functions for fatal error handler
 408 
 409 void os::print_context(outputStream* st, void* context) {
 410   ShouldNotCallThis();
 411 }
 412 
 413 void os::print_register_info(outputStream *st, void *context) {
 414   ShouldNotCallThis();
 415 }
 416 
 417 /////////////////////////////////////////////////////////////////////////////
 418 // Stubs for things that would be in linux_zero.s if it existed.
 419 // You probably want to disassemble these monkeys to check they're ok.
 420 
 421 extern "C" {
 422   int SpinPause() {
 423   }
 424 
 425 
 426   void _Copy_conjoint_jshorts_atomic(jshort* from, jshort* to, size_t count) {
 427     if (from > to) {
 428       jshort *end = from + count;
 429       while (from < end)
 430         *(to++) = *(from++);
 431     }
 432     else if (from < to) {
 433       jshort *end = from;
 434       from += count - 1;
 435       to   += count - 1;
 436       while (from >= end)
 437         *(to--) = *(from--);
 438     }
 439   }
 440   void _Copy_conjoint_jints_atomic(jint* from, jint* to, size_t count) {
 441     if (from > to) {
 442       jint *end = from + count;
 443       while (from < end)
 444         *(to++) = *(from++);
 445     }
 446     else if (from < to) {
 447       jint *end = from;
 448       from += count - 1;
 449       to   += count - 1;
 450       while (from >= end)
 451         *(to--) = *(from--);
 452     }
 453   }
 454   void _Copy_conjoint_jlongs_atomic(jlong* from, jlong* to, size_t count) {
 455     if (from > to) {
 456       jlong *end = from + count;
 457       while (from < end)
 458         os::atomic_copy64(from++, to++);
 459     }
 460     else if (from < to) {
 461       jlong *end = from;
 462       from += count - 1;
 463       to   += count - 1;
 464       while (from >= end)
 465         os::atomic_copy64(from--, to--);
 466     }
 467   }
 468 
 469   void _Copy_arrayof_conjoint_bytes(HeapWord* from,
 470                                     HeapWord* to,
 471                                     size_t    count) {
 472     memmove(to, from, count);
 473   }
 474   void _Copy_arrayof_conjoint_jshorts(HeapWord* from,
 475                                       HeapWord* to,
 476                                       size_t    count) {
 477     memmove(to, from, count * 2);
 478   }
 479   void _Copy_arrayof_conjoint_jints(HeapWord* from,
 480                                     HeapWord* to,
 481                                     size_t    count) {
 482     memmove(to, from, count * 4);
 483   }
 484   void _Copy_arrayof_conjoint_jlongs(HeapWord* from,
 485                                      HeapWord* to,
 486                                      size_t    count) {
 487     memmove(to, from, count * 8);
 488   }
 489 };
 490 
 491 /////////////////////////////////////////////////////////////////////////////
 492 // Implementations of atomic operations not supported by processors.
 493 //  -- http://gcc.gnu.org/onlinedocs/gcc-4.2.1/gcc/Atomic-Builtins.html
 494 
 495 #ifndef _LP64
 496 extern "C" {
 497   long long unsigned int __sync_val_compare_and_swap_8(
 498     volatile void *ptr,
 499     long long unsigned int oldval,
 500     long long unsigned int newval) {
 501     ShouldNotCallThis();
 502   }
 503 };
 504 #endif // !_LP64
 505 
 506 #ifndef PRODUCT
 507 void os::verify_stack_alignment() {
 508 }
 509 #endif
 510 
 511 int os::extra_bang_size_in_bytes() {
 512   // Zero does not require an additional stack banging.
 513   return 0;
 514 }