1 /* 2 * Copyright (c) 2003, 2010, 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 "runtime/frame.inline.hpp" 27 #include "thread_solaris.inline.hpp" 28 29 // For Forte Analyzer AsyncGetCallTrace profiling support - thread is 30 // currently interrupted by SIGPROF 31 // 32 // NOTE: On Solaris, register windows are flushed in the signal handler 33 // except for possibly the top frame. 34 // 35 bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr, 36 void* ucontext, bool isInJava) { 37 38 assert(Thread::current() == this, "caller must be current thread"); 39 assert(this->is_Java_thread(), "must be JavaThread"); 40 41 JavaThread* jt = (JavaThread *)this; 42 43 if (!isInJava) { 44 // make_walkable flushes register windows and grabs last_Java_pc 45 // which can not be done if the ucontext sp matches last_Java_sp 46 // stack walking utilities assume last_Java_pc set if marked flushed 47 jt->frame_anchor()->make_walkable(jt); 48 } 49 50 // If we have a walkable last_Java_frame, then we should use it 51 // even if isInJava == true. It should be more reliable than 52 // ucontext info. 53 if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) { 54 *fr_addr = jt->pd_last_frame(); 55 return true; 56 } 57 58 ucontext_t* uc = (ucontext_t*) ucontext; 59 60 // At this point, we don't have a walkable last_Java_frame, so 61 // we try to glean some information out of the ucontext. 62 intptr_t* ret_sp; 63 ExtendedPC addr = os::Solaris::fetch_frame_from_ucontext(this, uc, 64 &ret_sp, NULL /* ret_fp only used on Solaris X86 */); 65 if (addr.pc() == NULL || ret_sp == NULL) { 66 // ucontext wasn't useful 67 return false; 68 } 69 70 frame ret_frame(ret_sp, frame::unpatchable, addr.pc()); 71 72 // we were running Java code when SIGPROF came in 73 if (isInJava) { 74 75 76 // If the frame we got is safe then it is most certainly valid 77 if (ret_frame.safe_for_sender(jt)) { 78 *fr_addr = ret_frame; 79 return true; 80 } 81 82 // If it isn't safe then we can try several things to try and get 83 // a good starting point. 84 // 85 // On sparc the frames are almost certainly walkable in the sense 86 // of sp/fp linkages. However because of recycling of windows if 87 // a piece of code does multiple save's where the initial save creates 88 // a real frame with a return pc and the succeeding save's are used to 89 // simply get free registers and have no real pc then the pc linkage on these 90 // "inner" temporary frames will be bogus. 91 // Since there is in general only a nesting level like 92 // this one deep in general we'll try and unwind such an "inner" frame 93 // here ourselves and see if it makes sense 94 95 frame unwind_frame(ret_frame.fp(), frame::unpatchable, addr.pc()); 96 97 if (unwind_frame.safe_for_sender(jt)) { 98 *fr_addr = unwind_frame; 99 return true; 100 } 101 102 // Well that didn't work. Most likely we're toast on this tick 103 // The previous code would try this. I think it is dubious in light 104 // of changes to safe_for_sender and the unwind trick above but 105 // if it gets us a safe frame who wants to argue. 106 107 // If we have a last_Java_sp, then the SIGPROF signal caught us 108 // right when we were transitioning from _thread_in_Java to a new 109 // JavaThreadState. We use last_Java_sp instead of the sp from 110 // the ucontext since it should be more reliable. 111 112 if (jt->has_last_Java_frame()) { 113 ret_sp = jt->last_Java_sp(); 114 frame ret_frame2(ret_sp, frame::unpatchable, addr.pc()); 115 if (ret_frame2.safe_for_sender(jt)) { 116 *fr_addr = ret_frame2; 117 return true; 118 } 119 } 120 121 // This is the best we can do. We will only be able to decode the top frame 122 123 *fr_addr = ret_frame; 124 return true; 125 } 126 127 // At this point, we know we weren't running Java code. We might 128 // have a last_Java_sp, but we don't have a walkable frame. 129 // However, we might still be able to construct something useful 130 // if the thread was running native code. 131 if (jt->has_last_Java_frame()) { 132 assert(!jt->frame_anchor()->walkable(), "case covered above"); 133 134 frame ret_frame(jt->last_Java_sp(), frame::unpatchable, addr.pc()); 135 *fr_addr = ret_frame; 136 return true; 137 } 138 139 // nothing else to try but what we found initially 140 141 *fr_addr = ret_frame; 142 return true; 143 } 144 145 void JavaThread::cache_global_variables() { } 146