1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)thread_solaris_sparc.cpp 1.16 07/05/05 17:04:53 JVM"
3 #endif
4 /*
5 * Copyright 2003-2008 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 #include "incls/_precompiled.incl"
29 #include "incls/_thread_solaris_sparc.cpp.incl"
30
31 // For Forte Analyzer AsyncGetCallTrace profiling support - thread is
32 // currently interrupted by SIGPROF
33 //
34 // NOTE: On Solaris, register windows are flushed in the signal handler
35 // except for possibly the top frame.
36 //
37 bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr,
38 void* ucontext, bool isInJava) {
39
40 assert(Thread::current() == this, "caller must be current thread");
41 assert(this->is_Java_thread(), "must be JavaThread");
42
43 JavaThread* jt = (JavaThread *)this;
44
45 if (!isInJava) {
46 // make_walkable flushes register windows and grabs last_Java_pc
47 // which can not be done if the ucontext sp matches last_Java_sp
48 // stack walking utilities assume last_Java_pc set if marked flushed
49 jt->frame_anchor()->make_walkable(jt);
50 }
51
52 // If we have a walkable last_Java_frame, then we should use it
53 // even if isInJava == true. It should be more reliable than
54 // ucontext info.
55 if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) {
56 *fr_addr = jt->pd_last_frame();
57 return true;
58 }
59
60 ucontext_t* uc = (ucontext_t*) ucontext;
61
62 // At this point, we don't have a walkable last_Java_frame, so
63 // we try to glean some information out of the ucontext.
64 intptr_t* ret_sp;
65 ExtendedPC addr = os::Solaris::fetch_frame_from_ucontext(this, uc,
66 &ret_sp, NULL /* ret_fp only used on Solaris X86 */);
67 if (addr.pc() == NULL || ret_sp == NULL) {
68 // ucontext wasn't useful
69 return false;
70 }
71
72 frame ret_frame(ret_sp, frame::unpatchable, addr.pc());
73
74 // we were running Java code when SIGPROF came in
75 if (isInJava) {
76
77
78 // If the frame we got is safe then it is most certainly valid
79 if (ret_frame.safe_for_sender(jt)) {
80 *fr_addr = ret_frame;
81 return true;
82 }
83
84 // If it isn't safe then we can try several things to try and get
85 // a good starting point.
86 //
87 // On sparc the frames are almost certainly walkable in the sense
88 // of sp/fp linkages. However because of recycling of windows if
89 // a piece of code does multiple save's where the initial save creates
90 // a real frame with a return pc and the succeeding save's are used to
91 // simply get free registers and have no real pc then the pc linkage on these
92 // "inner" temporary frames will be bogus.
93 // Since there is in general only a nesting level like
94 // this one deep in general we'll try and unwind such an "inner" frame
95 // here ourselves and see if it makes sense
96
97 frame unwind_frame(ret_frame.fp(), frame::unpatchable, addr.pc());
98
99 if (unwind_frame.safe_for_sender(jt)) {
100 *fr_addr = unwind_frame;
101 return true;
102 }
103
104 // Well that didn't work. Most likely we're toast on this tick
105 // The previous code would try this. I think it is dubious in light
106 // of changes to safe_for_sender and the unwind trick above but
107 // if it gets us a safe frame who wants to argue.
108
109 // If we have a last_Java_sp, then the SIGPROF signal caught us
110 // right when we were transitioning from _thread_in_Java to a new
111 // JavaThreadState. We use last_Java_sp instead of the sp from
112 // the ucontext since it should be more reliable.
113
114 if (jt->has_last_Java_frame()) {
115 ret_sp = jt->last_Java_sp();
116 frame ret_frame2(ret_sp, frame::unpatchable, addr.pc());
117 if (ret_frame2.safe_for_sender(jt)) {
118 *fr_addr = ret_frame2;
119 return true;
120 }
121 }
122
123 // This is the best we can do. We will only be able to decode the top frame
124
125 *fr_addr = ret_frame;
126 return true;
127 }
128
129 // At this point, we know we weren't running Java code. We might
130 // have a last_Java_sp, but we don't have a walkable frame.
131 // However, we might still be able to construct something useful
132 // if the thread was running native code.
133 if (jt->has_last_Java_frame()) {
134 assert(!jt->frame_anchor()->walkable(), "case covered above");
135
136 frame ret_frame(jt->last_Java_sp(), frame::unpatchable, addr.pc());
137 *fr_addr = ret_frame;
138 return true;
139 }
140
141 // nothing else to try but what we found initially
142
143 *fr_addr = ret_frame;
144 return true;
145 }