1 /*
   2  * Copyright (c) 2008, 2016, 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/cardTableModRefBS.inline.hpp"
  28 #include "gc/shared/collectedHeap.hpp"
  29 #include "memory/metaspaceShared.hpp"
  30 #include "runtime/frame.inline.hpp"
  31 
  32 void JavaThread::cache_global_variables() {
  33   BarrierSet* bs = Universe::heap()->barrier_set();
  34 
  35   const bool allow_shared_alloc =
  36     Universe::heap()->supports_inline_contig_alloc();
  37 
  38   if (allow_shared_alloc) {
  39     _heap_top_addr = (address) Universe::heap()->top_addr();
  40   } else {
  41     _heap_top_addr = NULL;
  42   }
  43 
  44   if (bs->is_a(BarrierSet::CardTableModRef)) {
  45     _card_table_base = (address) (barrier_set_cast<CardTableModRefBS>(bs)->byte_map_base);
  46   } else {
  47     _card_table_base = NULL;
  48   }
  49 
  50 }
  51 
  52 // For Forte Analyzer AsyncGetCallTrace profiling support - thread is
  53 // currently interrupted by SIGPROF
  54 bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr,
  55   void* ucontext, bool isInJava) {
  56   assert(Thread::current() == this, "caller must be current thread");
  57   return pd_get_top_frame(fr_addr, ucontext, isInJava);
  58 }
  59 
  60 bool JavaThread::pd_get_top_frame_for_profiling(frame* fr_addr, void* ucontext, bool isInJava) {
  61   return pd_get_top_frame(fr_addr, ucontext, isInJava);
  62 }
  63 
  64 bool JavaThread::pd_get_top_frame(frame* fr_addr, void* ucontext, bool isInJava) {
  65   assert(this->is_Java_thread(), "must be JavaThread");
  66 
  67   JavaThread* jt = (JavaThread *)this;
  68 
  69   // If we have a last_Java_frame, then we should use it even if
  70   // isInJava == true.  It should be more reliable than ucontext info.
  71   if (jt->has_last_Java_frame() AARCH64_ONLY(&& jt->last_Java_pc() != NULL)) {
  72     *fr_addr = jt->pd_last_frame();
  73     return true;
  74   }
  75 
  76   // At this point, we don't have a last_Java_frame, so
  77   // we try to glean some information out of the ucontext
  78   // if we were running Java code when SIGPROF came in.
  79   if (isInJava) {
  80     ucontext_t* uc = (ucontext_t*) ucontext;
  81 
  82     intptr_t* ret_fp;
  83     intptr_t* ret_sp;
  84     ExtendedPC addr = os::Linux::fetch_frame_from_ucontext(this, uc,
  85       &ret_sp, &ret_fp);
  86     if (addr.pc() == NULL || ret_sp == NULL ) {
  87       // ucontext wasn't useful
  88       return false;
  89     }
  90 
  91 #if INCLUDE_CDS
  92     if (UseSharedSpaces && MetaspaceShared::is_in_shared_region(addr.pc(), MetaspaceShared::md)) {
  93       // In the middle of a trampoline call. Bail out for safety.
  94       // This happens rarely so shouldn't affect profiling.
  95       return false;
  96     }
  97 #endif
  98 
  99     frame ret_frame(ret_sp, ret_fp, addr.pc());
 100     if (!ret_frame.safe_for_sender(jt)) {
 101 #ifdef COMPILER2
 102       // C2 uses ebp as a general register see if NULL fp helps
 103       frame ret_frame2(ret_sp, NULL, addr.pc());
 104       if (!ret_frame2.safe_for_sender(jt)) {
 105         // nothing else to try if the frame isn't good
 106         return false;
 107       }
 108       ret_frame = ret_frame2;
 109 #else
 110       // nothing else to try if the frame isn't good
 111       return false;
 112 #endif /* COMPILER2 */
 113     }
 114     *fr_addr = ret_frame;
 115     return true;
 116   }
 117 
 118   // nothing else to try
 119   return false;
 120 }