1 /*
   2  * Copyright (c) 2003, 2016, 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 "nativeInst_zero.hpp"
  37 #include "os_share_linux.hpp"
  38 #include "prims/jniFastGetField.hpp"
  39 #include "prims/jvm.h"
  40 #include "prims/jvm_misc.hpp"
  41 #include "runtime/arguments.hpp"
  42 #include "runtime/extendedPC.hpp"
  43 #include "runtime/frame.inline.hpp"
  44 #include "runtime/interfaceSupport.hpp"
  45 #include "runtime/java.hpp"
  46 #include "runtime/javaCalls.hpp"
  47 #include "runtime/mutexLocker.hpp"
  48 #include "runtime/osThread.hpp"
  49 #include "runtime/sharedRuntime.hpp"
  50 #include "runtime/stubRoutines.hpp"
  51 #include "runtime/thread.inline.hpp"
  52 #include "runtime/timer.hpp"
  53 #include "utilities/events.hpp"
  54 #include "utilities/vmError.hpp"
  55 
  56 // See stubGenerator_zero.cpp
  57 #include <setjmp.h>
  58 extern sigjmp_buf* get_jmp_buf_for_continuation();
  59 
  60 address os::current_stack_pointer() {
  61   // return the address of the current function
  62   return (address)__builtin_frame_address(0);
  63 }
  64 
  65 frame os::get_sender_for_C_frame(frame* fr) {
  66   ShouldNotCallThis();
  67   return frame(NULL, NULL); // silence compile warning.
  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(const ucontext_t* uc) {
 104   ShouldNotCallThis();
 105   return NULL; // silence compile warnings
 106 }
 107 
 108 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
 109   ShouldNotCallThis();
 110 }
 111 
 112 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
 113                                         intptr_t** ret_sp,
 114                                         intptr_t** ret_fp) {
 115   ShouldNotCallThis();
 116   return NULL; // silence compile warnings
 117 }
 118 
 119 frame os::fetch_frame_from_context(const void* ucVoid) {
 120   ShouldNotCallThis();
 121   return frame(NULL, NULL); // silence compile warnings
 122 }
 123 
 124 extern "C" JNIEXPORT int
 125 JVM_handle_linux_signal(int sig,
 126                         siginfo_t* info,
 127                         void* ucVoid,
 128                         int abort_if_unrecognized) {
 129   ucontext_t* uc = (ucontext_t*) ucVoid;
 130 
 131   Thread* t = Thread::current_or_null_safe();
 132 
 133   SignalHandlerMark shm(t);
 134 
 135   // handle SafeFetch faults
 136   if (sig == SIGSEGV || sig == SIGBUS) {
 137     sigjmp_buf* const pjb = get_jmp_buf_for_continuation();
 138     if (pjb) {
 139       siglongjmp(*pjb, 1);
 140     }
 141   }
 142 
 143   // Note: it's not uncommon that JNI code uses signal/sigset to
 144   // install then restore certain signal handler (e.g. to temporarily
 145   // block SIGPIPE, or have a SIGILL handler when detecting CPU
 146   // type). When that happens, JVM_handle_linux_signal() might be
 147   // invoked with junk info/ucVoid. To avoid unnecessary crash when
 148   // libjsig is not preloaded, try handle signals that do not require
 149   // siginfo/ucontext first.
 150 
 151   if (sig == SIGPIPE || sig == SIGXFSZ) {
 152     // allow chained handler to go first
 153     if (os::Linux::chained_handler(sig, info, ucVoid)) {
 154       return true;
 155     } else {
 156       // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
 157       return true;
 158     }
 159   }
 160 
 161   JavaThread* thread = NULL;
 162   VMThread* vmthread = NULL;
 163   if (os::Linux::signal_handlers_are_installed) {
 164     if (t != NULL ){
 165       if(t->is_Java_thread()) {
 166         thread = (JavaThread*)t;
 167       }
 168       else if(t->is_VM_thread()){
 169         vmthread = (VMThread *)t;
 170       }
 171     }
 172   }
 173 
 174   if (info != NULL && thread != NULL) {
 175     // Handle ALL stack overflow variations here
 176     if (sig == SIGSEGV) {
 177       address addr = (address) info->si_addr;
 178 
 179       // check if fault address is within thread stack
 180       if (thread->on_local_stack(addr)) {
 181         // stack overflow
 182         if (thread->in_stack_yellow_reserved_zone(addr)) {
 183           thread->disable_stack_yellow_reserved_zone();
 184           ShouldNotCallThis();
 185         }
 186         else if (thread->in_stack_red_zone(addr)) {
 187           thread->disable_stack_red_zone();
 188           ShouldNotCallThis();
 189         }
 190         else {
 191           // Accessing stack address below sp may cause SEGV if
 192           // current thread has MAP_GROWSDOWN stack. This should
 193           // only happen when current thread was created by user
 194           // code with MAP_GROWSDOWN flag and then attached to VM.
 195           // See notes in os_linux.cpp.
 196           if (thread->osthread()->expanding_stack() == 0) {
 197             thread->osthread()->set_expanding_stack();
 198             if (os::Linux::manually_expand_stack(thread, addr)) {
 199               thread->osthread()->clear_expanding_stack();
 200               return true;
 201             }
 202             thread->osthread()->clear_expanding_stack();
 203           }
 204           else {
 205             fatal("recursive segv. expanding stack.");
 206           }
 207         }
 208       }
 209     }
 210 
 211     /*if (thread->thread_state() == _thread_in_Java) {
 212       ShouldNotCallThis();
 213     }
 214     else*/ if (thread->thread_state() == _thread_in_vm &&
 215                sig == SIGBUS && thread->doing_unsafe_access()) {
 216       ShouldNotCallThis();
 217     }
 218 
 219     // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC
 220     // kicks in and the heap gets shrunk before the field access.
 221     /*if (sig == SIGSEGV || sig == SIGBUS) {
 222       address addr = JNI_FastGetField::find_slowcase_pc(pc);
 223       if (addr != (address)-1) {
 224         stub = addr;
 225       }
 226     }*/
 227 
 228     // Check to see if we caught the safepoint code in the process
 229     // of write protecting the memory serialization page.  It write
 230     // enables the page immediately after protecting it so we can
 231     // just return to retry the write.
 232     if (sig == SIGSEGV &&
 233         os::is_memory_serialize_page(thread, (address) info->si_addr)) {
 234       // Block current thread until permission is restored.
 235       os::block_on_serialize_page_trap();
 236       return true;
 237     }
 238   }
 239 
 240   // signal-chaining
 241   if (os::Linux::chained_handler(sig, info, ucVoid)) {
 242      return true;
 243   }
 244 
 245   if (!abort_if_unrecognized) {
 246     // caller wants another chance, so give it to him
 247     return false;
 248   }
 249 
 250 #ifndef PRODUCT
 251   if (sig == SIGSEGV) {
 252     fatal("\n#"
 253           "\n#    /--------------------\\"
 254           "\n#    | segmentation fault |"
 255           "\n#    \\---\\ /--------------/"
 256           "\n#        /"
 257           "\n#    [-]        |\\_/|    "
 258           "\n#    (+)=C      |o o|__  "
 259           "\n#    | |        =-*-=__\\ "
 260           "\n#    OOO        c_c_(___)");
 261   }
 262 #endif // !PRODUCT
 263 
 264   char buf[64];
 265 
 266   sprintf(buf, "caught unhandled signal %d", sig);
 267 
 268 // Silence -Wformat-security warning for fatal()
 269 PRAGMA_DIAG_PUSH
 270 PRAGMA_FORMAT_NONLITERAL_IGNORED
 271   fatal(buf);
 272 PRAGMA_DIAG_POP
 273   return true; // silence compiler warnings
 274 }
 275 
 276 void os::Linux::init_thread_fpu_state(void) {
 277   // Nothing to do
 278 }
 279 
 280 int os::Linux::get_fpu_control_word() {
 281   ShouldNotCallThis();
 282   return -1; // silence compile warnings
 283 }
 284 
 285 void os::Linux::set_fpu_control_word(int fpu) {
 286   ShouldNotCallThis();
 287 }
 288 
 289 bool os::is_allocatable(size_t bytes) {
 290 #ifdef _LP64
 291   return true;
 292 #else
 293   if (bytes < 2 * G) {
 294     return true;
 295   }
 296 
 297   char* addr = reserve_memory(bytes, NULL);
 298 
 299   if (addr != NULL) {
 300     release_memory(addr, bytes);
 301   }
 302 
 303   return addr != NULL;
 304 #endif // _LP64
 305 }
 306 
 307 ///////////////////////////////////////////////////////////////////////////////
 308 // thread stack
 309 
 310 size_t os::Posix::_compiler_thread_min_stack_allowed = 64 * K;
 311 size_t os::Posix::_java_thread_min_stack_allowed = 64 * K;
 312 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
 313 
 314 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
 315 #ifdef _LP64
 316   size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
 317 #else
 318   size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
 319 #endif // _LP64
 320   return s;
 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, const void* context) {
 410   ShouldNotCallThis();
 411 }
 412 
 413 void os::print_register_info(outputStream *st, const 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       return -1; // silence compile warnings
 424   }
 425 
 426 
 427   void _Copy_conjoint_jshorts_atomic(jshort* from, jshort* to, size_t count) {
 428     if (from > to) {
 429       jshort *end = from + count;
 430       while (from < end)
 431         *(to++) = *(from++);
 432     }
 433     else if (from < to) {
 434       jshort *end = from;
 435       from += count - 1;
 436       to   += count - 1;
 437       while (from >= end)
 438         *(to--) = *(from--);
 439     }
 440   }
 441   void _Copy_conjoint_jints_atomic(jint* from, jint* to, size_t count) {
 442     if (from > to) {
 443       jint *end = from + count;
 444       while (from < end)
 445         *(to++) = *(from++);
 446     }
 447     else if (from < to) {
 448       jint *end = from;
 449       from += count - 1;
 450       to   += count - 1;
 451       while (from >= end)
 452         *(to--) = *(from--);
 453     }
 454   }
 455   void _Copy_conjoint_jlongs_atomic(jlong* from, jlong* to, size_t count) {
 456     if (from > to) {
 457       jlong *end = from + count;
 458       while (from < end)
 459         os::atomic_copy64(from++, to++);
 460     }
 461     else if (from < to) {
 462       jlong *end = from;
 463       from += count - 1;
 464       to   += count - 1;
 465       while (from >= end)
 466         os::atomic_copy64(from--, to--);
 467     }
 468   }
 469 
 470   void _Copy_arrayof_conjoint_bytes(HeapWord* from,
 471                                     HeapWord* to,
 472                                     size_t    count) {
 473     memmove(to, from, count);
 474   }
 475   void _Copy_arrayof_conjoint_jshorts(HeapWord* from,
 476                                       HeapWord* to,
 477                                       size_t    count) {
 478     memmove(to, from, count * 2);
 479   }
 480   void _Copy_arrayof_conjoint_jints(HeapWord* from,
 481                                     HeapWord* to,
 482                                     size_t    count) {
 483     memmove(to, from, count * 4);
 484   }
 485   void _Copy_arrayof_conjoint_jlongs(HeapWord* from,
 486                                      HeapWord* to,
 487                                      size_t    count) {
 488     memmove(to, from, count * 8);
 489   }
 490 };
 491 
 492 /////////////////////////////////////////////////////////////////////////////
 493 // Implementations of atomic operations not supported by processors.
 494 //  -- http://gcc.gnu.org/onlinedocs/gcc-4.2.1/gcc/Atomic-Builtins.html
 495 
 496 #ifndef _LP64
 497 extern "C" {
 498   long long unsigned int __sync_val_compare_and_swap_8(
 499     volatile void *ptr,
 500     long long unsigned int oldval,
 501     long long unsigned int newval) {
 502     ShouldNotCallThis();
 503   }
 504 };
 505 #endif // !_LP64
 506 
 507 #ifndef PRODUCT
 508 void os::verify_stack_alignment() {
 509 }
 510 #endif
 511 
 512 int os::extra_bang_size_in_bytes() {
 513   // Zero does not require an additional stack banging.
 514   return 0;
 515 }