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.hpp"
 27 #include "gc/shared/cardTable.hpp"
 28 #include "gc/shared/cardTableModRefBS.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::CardTableModRef)) {
 46     _card_table_base = (address) (barrier_set_cast<CardTableModRefBS>(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 }