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