1 /* 2 * Copyright (c) 2003, 2017, 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 "memory/metaspaceShared.hpp" 27 #include "runtime/frame.inline.hpp" 28 #include "runtime/thread.inline.hpp" 29 30 frame JavaThread::pd_last_frame() { 31 assert(has_last_Java_frame(), "must have last_Java_sp() when suspended"); 32 assert(_anchor.walkable(), "thread has not dumped its register windows yet"); 33 34 assert(_anchor.last_Java_pc() != NULL, "Ack no pc!"); 35 return frame(last_Java_sp(), frame::unpatchable, _anchor.last_Java_pc()); 36 } 37 38 // For Forte Analyzer AsyncGetCallTrace profiling support - thread is 39 // currently interrupted by SIGPROF 40 // 41 // NOTE: On Solaris, register windows are flushed in the signal handler 42 // except for possibly the top frame. 43 // 44 bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr, 45 void* ucontext, bool isInJava) { 46 47 assert(Thread::current() == this, "caller must be current thread"); 48 return pd_get_top_frame(fr_addr, ucontext, isInJava, true); 49 } 50 51 bool JavaThread::pd_get_top_frame_for_profiling(frame* fr_addr, void* ucontext, bool isInJava) { 52 // get ucontext somehow 53 return pd_get_top_frame(fr_addr, ucontext, isInJava, false); 54 } 55 56 bool JavaThread::pd_get_top_frame(frame* fr_addr, 57 void* ucontext, bool isInJava, bool makeWalkable) { 58 assert(this->is_Java_thread(), "must be JavaThread"); 59 60 JavaThread* jt = (JavaThread *)this; 61 62 if (!isInJava && makeWalkable) { 63 // make_walkable flushes register windows and grabs last_Java_pc 64 // which can not be done if the ucontext sp matches last_Java_sp 65 // stack walking utilities assume last_Java_pc set if marked flushed 66 jt->frame_anchor()->make_walkable(jt); 67 } 68 69 // If we have a walkable last_Java_frame, then we should use it 70 // even if isInJava == true. It should be more reliable than 71 // ucontext info. 72 if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) { 73 *fr_addr = jt->pd_last_frame(); 74 return true; 75 } 76 77 ucontext_t* uc = (ucontext_t*) ucontext; 78 79 // At this point, we don't have a walkable last_Java_frame, so 80 // we try to glean some information out of the ucontext. 81 intptr_t* ret_sp; 82 ExtendedPC addr = os::Solaris::fetch_frame_from_ucontext(this, uc, 83 &ret_sp, NULL /* ret_fp only used on Solaris X86 */); 84 if (addr.pc() == NULL || ret_sp == NULL) { 85 // ucontext wasn't useful 86 return false; 87 } 88 89 if (MetaspaceShared::is_in_trampoline_frame(addr.pc())) { 90 // In the middle of a trampoline call. Bail out for safety. 91 // This happens rarely so shouldn't affect profiling. 92 return false; 93 } 94 95 frame ret_frame(ret_sp, frame::unpatchable, addr.pc()); 96 97 // we were running Java code when SIGPROF came in 98 if (isInJava) { 99 100 101 // If the frame we got is safe then it is most certainly valid 102 if (ret_frame.safe_for_sender(jt)) { 103 *fr_addr = ret_frame; 104 return true; 105 } 106 107 // If it isn't safe then we can try several things to try and get 108 // a good starting point. 109 // 110 // On sparc the frames are almost certainly walkable in the sense 111 // of sp/fp linkages. However because of recycling of windows if 112 // a piece of code does multiple save's where the initial save creates 113 // a real frame with a return pc and the succeeding save's are used to 114 // simply get free registers and have no real pc then the pc linkage on these 115 // "inner" temporary frames will be bogus. 116 // Since there is in general only a nesting level like 117 // this one deep in general we'll try and unwind such an "inner" frame 118 // here ourselves and see if it makes sense 119 120 frame unwind_frame(ret_frame.fp(), frame::unpatchable, addr.pc()); 121 122 if (unwind_frame.safe_for_sender(jt)) { 123 *fr_addr = unwind_frame; 124 return true; 125 } 126 127 // Well that didn't work. Most likely we're toast on this tick 128 // The previous code would try this. I think it is dubious in light 129 // of changes to safe_for_sender and the unwind trick above but 130 // if it gets us a safe frame who wants to argue. 131 132 // If we have a last_Java_sp, then the SIGPROF signal caught us 133 // right when we were transitioning from _thread_in_Java to a new 134 // JavaThreadState. We use last_Java_sp instead of the sp from 135 // the ucontext since it should be more reliable. 136 137 if (jt->has_last_Java_frame()) { 138 ret_sp = jt->last_Java_sp(); 139 frame ret_frame2(ret_sp, frame::unpatchable, addr.pc()); 140 if (ret_frame2.safe_for_sender(jt)) { 141 *fr_addr = ret_frame2; 142 return true; 143 } 144 } 145 146 // This is the best we can do. We will only be able to decode the top frame 147 148 *fr_addr = ret_frame; 149 return true; 150 } 151 152 // At this point, we know we weren't running Java code. We might 153 // have a last_Java_sp, but we don't have a walkable frame. 154 // However, we might still be able to construct something useful 155 // if the thread was running native code. 156 if (jt->has_last_Java_frame()) { 157 assert(!jt->frame_anchor()->walkable(), "case covered above"); 158 159 frame ret_frame(jt->last_Java_sp(), frame::unpatchable, addr.pc()); 160 *fr_addr = ret_frame; 161 return true; 162 } 163 164 // nothing else to try but what we found initially 165 166 *fr_addr = ret_frame; 167 return true; 168 } 169 170 void JavaThread::cache_global_variables() { } 171