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