Thu, 26 Mar 2009 14:31:45 -0700
6822204: volatile fences should prefer lock:addl to actual mfence instructions
Reviewed-by: kvn, phh
duke@435 | 1 | /* |
xdono@631 | 2 | * Copyright 2003-2008 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | #include "incls/_precompiled.incl" |
duke@435 | 26 | #include "incls/_thread_solaris_sparc.cpp.incl" |
duke@435 | 27 | |
duke@435 | 28 | // For Forte Analyzer AsyncGetCallTrace profiling support - thread is |
duke@435 | 29 | // currently interrupted by SIGPROF |
duke@435 | 30 | // |
duke@435 | 31 | // NOTE: On Solaris, register windows are flushed in the signal handler |
duke@435 | 32 | // except for possibly the top frame. |
duke@435 | 33 | // |
duke@435 | 34 | bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr, |
duke@435 | 35 | void* ucontext, bool isInJava) { |
duke@435 | 36 | |
duke@435 | 37 | assert(Thread::current() == this, "caller must be current thread"); |
duke@435 | 38 | assert(this->is_Java_thread(), "must be JavaThread"); |
duke@435 | 39 | |
duke@435 | 40 | JavaThread* jt = (JavaThread *)this; |
duke@435 | 41 | |
duke@435 | 42 | if (!isInJava) { |
duke@435 | 43 | // make_walkable flushes register windows and grabs last_Java_pc |
duke@435 | 44 | // which can not be done if the ucontext sp matches last_Java_sp |
duke@435 | 45 | // stack walking utilities assume last_Java_pc set if marked flushed |
duke@435 | 46 | jt->frame_anchor()->make_walkable(jt); |
duke@435 | 47 | } |
duke@435 | 48 | |
duke@435 | 49 | // If we have a walkable last_Java_frame, then we should use it |
duke@435 | 50 | // even if isInJava == true. It should be more reliable than |
duke@435 | 51 | // ucontext info. |
duke@435 | 52 | if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) { |
duke@435 | 53 | *fr_addr = jt->pd_last_frame(); |
duke@435 | 54 | return true; |
duke@435 | 55 | } |
duke@435 | 56 | |
duke@435 | 57 | ucontext_t* uc = (ucontext_t*) ucontext; |
duke@435 | 58 | |
duke@435 | 59 | // At this point, we don't have a walkable last_Java_frame, so |
duke@435 | 60 | // we try to glean some information out of the ucontext. |
duke@435 | 61 | intptr_t* ret_sp; |
duke@435 | 62 | ExtendedPC addr = os::Solaris::fetch_frame_from_ucontext(this, uc, |
duke@435 | 63 | &ret_sp, NULL /* ret_fp only used on Solaris X86 */); |
duke@435 | 64 | if (addr.pc() == NULL || ret_sp == NULL) { |
duke@435 | 65 | // ucontext wasn't useful |
duke@435 | 66 | return false; |
duke@435 | 67 | } |
duke@435 | 68 | |
sgoldman@542 | 69 | frame ret_frame(ret_sp, frame::unpatchable, addr.pc()); |
sgoldman@542 | 70 | |
duke@435 | 71 | // we were running Java code when SIGPROF came in |
duke@435 | 72 | if (isInJava) { |
sgoldman@542 | 73 | |
sgoldman@542 | 74 | |
sgoldman@542 | 75 | // If the frame we got is safe then it is most certainly valid |
sgoldman@542 | 76 | if (ret_frame.safe_for_sender(jt)) { |
sgoldman@542 | 77 | *fr_addr = ret_frame; |
sgoldman@542 | 78 | return true; |
sgoldman@542 | 79 | } |
sgoldman@542 | 80 | |
sgoldman@542 | 81 | // If it isn't safe then we can try several things to try and get |
sgoldman@542 | 82 | // a good starting point. |
sgoldman@542 | 83 | // |
sgoldman@542 | 84 | // On sparc the frames are almost certainly walkable in the sense |
sgoldman@542 | 85 | // of sp/fp linkages. However because of recycling of windows if |
sgoldman@542 | 86 | // a piece of code does multiple save's where the initial save creates |
sgoldman@542 | 87 | // a real frame with a return pc and the succeeding save's are used to |
sgoldman@542 | 88 | // simply get free registers and have no real pc then the pc linkage on these |
sgoldman@542 | 89 | // "inner" temporary frames will be bogus. |
sgoldman@542 | 90 | // Since there is in general only a nesting level like |
sgoldman@542 | 91 | // this one deep in general we'll try and unwind such an "inner" frame |
sgoldman@542 | 92 | // here ourselves and see if it makes sense |
sgoldman@542 | 93 | |
sgoldman@542 | 94 | frame unwind_frame(ret_frame.fp(), frame::unpatchable, addr.pc()); |
sgoldman@542 | 95 | |
sgoldman@542 | 96 | if (unwind_frame.safe_for_sender(jt)) { |
sgoldman@542 | 97 | *fr_addr = unwind_frame; |
sgoldman@542 | 98 | return true; |
sgoldman@542 | 99 | } |
sgoldman@542 | 100 | |
sgoldman@542 | 101 | // Well that didn't work. Most likely we're toast on this tick |
sgoldman@542 | 102 | // The previous code would try this. I think it is dubious in light |
sgoldman@542 | 103 | // of changes to safe_for_sender and the unwind trick above but |
sgoldman@542 | 104 | // if it gets us a safe frame who wants to argue. |
sgoldman@542 | 105 | |
duke@435 | 106 | // If we have a last_Java_sp, then the SIGPROF signal caught us |
duke@435 | 107 | // right when we were transitioning from _thread_in_Java to a new |
duke@435 | 108 | // JavaThreadState. We use last_Java_sp instead of the sp from |
duke@435 | 109 | // the ucontext since it should be more reliable. |
sgoldman@542 | 110 | |
duke@435 | 111 | if (jt->has_last_Java_frame()) { |
duke@435 | 112 | ret_sp = jt->last_Java_sp(); |
sgoldman@542 | 113 | frame ret_frame2(ret_sp, frame::unpatchable, addr.pc()); |
sgoldman@542 | 114 | if (ret_frame2.safe_for_sender(jt)) { |
sgoldman@542 | 115 | *fr_addr = ret_frame2; |
sgoldman@542 | 116 | return true; |
sgoldman@542 | 117 | } |
duke@435 | 118 | } |
duke@435 | 119 | |
sgoldman@542 | 120 | // This is the best we can do. We will only be able to decode the top frame |
sgoldman@542 | 121 | |
duke@435 | 122 | *fr_addr = ret_frame; |
duke@435 | 123 | return true; |
duke@435 | 124 | } |
duke@435 | 125 | |
duke@435 | 126 | // At this point, we know we weren't running Java code. We might |
duke@435 | 127 | // have a last_Java_sp, but we don't have a walkable frame. |
duke@435 | 128 | // However, we might still be able to construct something useful |
duke@435 | 129 | // if the thread was running native code. |
duke@435 | 130 | if (jt->has_last_Java_frame()) { |
duke@435 | 131 | assert(!jt->frame_anchor()->walkable(), "case covered above"); |
duke@435 | 132 | |
sgoldman@542 | 133 | frame ret_frame(jt->last_Java_sp(), frame::unpatchable, addr.pc()); |
sgoldman@542 | 134 | *fr_addr = ret_frame; |
sgoldman@542 | 135 | return true; |
duke@435 | 136 | } |
duke@435 | 137 | |
sgoldman@542 | 138 | // nothing else to try but what we found initially |
sgoldman@542 | 139 | |
sgoldman@542 | 140 | *fr_addr = ret_frame; |
sgoldman@542 | 141 | return true; |
duke@435 | 142 | } |