1/*
2 * Copyright (c) 2003, 2013, 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//
36bool 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
43bool 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
48bool 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 INCLUDE_CDS
82  if (UseSharedSpaces && MetaspaceShared::is_in_shared_region(addr.pc(), MetaspaceShared::md)) {
83    // In the middle of a trampoline call. Bail out for safety.
84    // This happens rarely so shouldn't affect profiling.
85    return false;
86  }
87#endif
88
89  frame ret_frame(ret_sp, frame::unpatchable, addr.pc());
90
91  // we were running Java code when SIGPROF came in
92  if (isInJava) {
93
94
95    // If the frame we got is safe then it is most certainly valid
96    if (ret_frame.safe_for_sender(jt)) {
97      *fr_addr = ret_frame;
98      return true;
99    }
100
101    // If it isn't safe then we can try several things to try and get
102    // a good starting point.
103    //
104    // On sparc the frames are almost certainly walkable in the sense
105    // of sp/fp linkages. However because of recycling of windows if
106    // a piece of code does multiple save's where the initial save creates
107    // a real frame with a return pc and the succeeding save's are used to
108    // simply get free registers and have no real pc then the pc linkage on these
109    // "inner" temporary frames will be bogus.
110    // Since there is in general only a nesting level like
111    // this one deep in general we'll try and unwind such an "inner" frame
112    // here ourselves and see if it makes sense
113
114    frame unwind_frame(ret_frame.fp(), frame::unpatchable, addr.pc());
115
116    if (unwind_frame.safe_for_sender(jt)) {
117      *fr_addr = unwind_frame;
118      return true;
119    }
120
121    // Well that didn't work. Most likely we're toast on this tick
122    // The previous code would try this. I think it is dubious in light
123    // of changes to safe_for_sender and the unwind trick above but
124    // if it gets us a safe frame who wants to argue.
125
126    // If we have a last_Java_sp, then the SIGPROF signal caught us
127    // right when we were transitioning from _thread_in_Java to a new
128    // JavaThreadState. We use last_Java_sp instead of the sp from
129    // the ucontext since it should be more reliable.
130
131    if (jt->has_last_Java_frame()) {
132      ret_sp = jt->last_Java_sp();
133      frame ret_frame2(ret_sp, frame::unpatchable, addr.pc());
134      if (ret_frame2.safe_for_sender(jt)) {
135        *fr_addr = ret_frame2;
136        return true;
137      }
138    }
139
140    // This is the best we can do. We will only be able to decode the top frame
141
142    *fr_addr = ret_frame;
143    return true;
144  }
145
146  // At this point, we know we weren't running Java code. We might
147  // have a last_Java_sp, but we don't have a walkable frame.
148  // However, we might still be able to construct something useful
149  // if the thread was running native code.
150  if (jt->has_last_Java_frame()) {
151    assert(!jt->frame_anchor()->walkable(), "case covered above");
152
153    frame ret_frame(jt->last_Java_sp(), frame::unpatchable, addr.pc());
154    *fr_addr = ret_frame;
155    return true;
156  }
157
158  // nothing else to try but what we found initially
159
160  *fr_addr = ret_frame;
161  return true;
162}
163
164void JavaThread::cache_global_variables() { }
165
166