1 /*
   2  * Copyright (c) 2008, 2018, 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 #include "precompiled.hpp"
  26 #include "gc/shared/barrierSet.inline.hpp"
  27 #include "gc/shared/cardTable.hpp"
  28 #include "gc/shared/cardTableBarrierSet.inline.hpp"
  29 #include "gc/shared/collectedHeap.hpp"
  30 #include "memory/metaspaceShared.hpp"
  31 #include "runtime/frame.inline.hpp"
  32 
  33 void JavaThread::cache_global_variables() {
  34   BarrierSet* bs = Universe::heap()->barrier_set();
  35 
  36   const bool allow_shared_alloc =
  37     Universe::heap()->supports_inline_contig_alloc();
  38 
  39   if (allow_shared_alloc) {
  40     _heap_top_addr = (address) Universe::heap()->top_addr();
  41   } else {
  42     _heap_top_addr = NULL;
  43   }
  44 
  45   if (bs->is_a(BarrierSet::CardTableBarrierSet)) {
  46     _card_table_base = (address) (barrier_set_cast<CardTableBarrierSet>(bs)->card_table()->byte_map_base());
  47   } else {
  48     _card_table_base = NULL;
  49   }
  50 
  51 }
  52 
  53 // For Forte Analyzer AsyncGetCallTrace profiling support - thread is
  54 // currently interrupted by SIGPROF
  55 bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr,
  56   void* ucontext, bool isInJava) {
  57   assert(Thread::current() == this, "caller must be current thread");
  58   return pd_get_top_frame(fr_addr, ucontext, isInJava);
  59 }
  60 
  61 bool JavaThread::pd_get_top_frame_for_profiling(frame* fr_addr, void* ucontext, bool isInJava) {
  62   return pd_get_top_frame(fr_addr, ucontext, isInJava);
  63 }
  64 
  65 bool JavaThread::pd_get_top_frame(frame* fr_addr, void* ucontext, bool isInJava) {
  66   assert(this->is_Java_thread(), "must be JavaThread");
  67 
  68   JavaThread* jt = (JavaThread *)this;
  69 
  70   // If we have a last_Java_frame, then we should use it even if
  71   // isInJava == true.  It should be more reliable than ucontext info.
  72   if (jt->has_last_Java_frame() AARCH64_ONLY(&& jt->last_Java_pc() != NULL)) {
  73     *fr_addr = jt->pd_last_frame();
  74     return true;
  75   }
  76 
  77   // Could be in a code section that plays with the stack, like
  78   // MacroAssembler::verify_heapbase()
  79   if (jt->in_top_frame_unsafe_section()) {
  80     return false;
  81   }
  82 
  83   // At this point, we don't have a last_Java_frame, so
  84   // we try to glean some information out of the ucontext
  85   // if we were running Java code when SIGPROF came in.
  86   if (isInJava) {
  87     ucontext_t* uc = (ucontext_t*) ucontext;
  88 
  89     intptr_t* ret_fp;
  90     intptr_t* ret_sp;
  91     ExtendedPC addr = os::Linux::fetch_frame_from_ucontext(this, uc,
  92       &ret_sp, &ret_fp);
  93     if (addr.pc() == NULL || ret_sp == NULL ) {
  94       // ucontext wasn't useful
  95       return false;
  96     }
  97 
  98     if (MetaspaceShared::is_in_trampoline_frame(addr.pc())) {
  99       // In the middle of a trampoline call. Bail out for safety.
 100       // This happens rarely so shouldn't affect profiling.
 101       return false;
 102     }
 103 
 104     frame ret_frame(ret_sp, ret_fp, addr.pc());
 105     if (!ret_frame.safe_for_sender(jt)) {
 106 #ifdef COMPILER2
 107       // C2 uses ebp as a general register see if NULL fp helps
 108       frame ret_frame2(ret_sp, NULL, addr.pc());
 109       if (!ret_frame2.safe_for_sender(jt)) {
 110         // nothing else to try if the frame isn't good
 111         return false;
 112       }
 113       ret_frame = ret_frame2;
 114 #else
 115       // nothing else to try if the frame isn't good
 116       return false;
 117 #endif /* COMPILER2 */
 118     }
 119     *fr_addr = ret_frame;
 120     return true;
 121   }
 122 
 123   // nothing else to try
 124   return false;
 125 }