1 /*
2 * Copyright (c) 2003, 2017, 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 frame JavaThread::pd_last_frame() {
31 assert(has_last_Java_frame(), "must have last_Java_sp() when suspended");
32 assert(_anchor.walkable(), "thread has not dumped its register windows yet");
33
34 assert(_anchor.last_Java_pc() != NULL, "Ack no pc!");
35 return frame(last_Java_sp(), frame::unpatchable, _anchor.last_Java_pc());
36 }
37
38 // For Forte Analyzer AsyncGetCallTrace profiling support - thread is
39 // currently interrupted by SIGPROF
40 bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr,
41 void* ucontext,
42 bool isInJava) {
43 assert(Thread::current() == this, "caller must be current thread");
44 assert(this->is_Java_thread(), "must be JavaThread");
45
46 JavaThread* jt = (JavaThread *)this;
47
48 if (!isInJava) {
49 // make_walkable flushes register windows and grabs last_Java_pc
50 // which can not be done if the ucontext sp matches last_Java_sp
51 // stack walking utilities assume last_Java_pc set if marked flushed
52 jt->frame_anchor()->make_walkable(jt);
53 }
54
55 // If we have a walkable last_Java_frame, then we should use it
56 // even if isInJava == true. It should be more reliable than
57 // ucontext info.
58 if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) {
59 *fr_addr = jt->pd_last_frame();
60 return true;
61 }
62
63 ucontext_t* uc = (ucontext_t*) ucontext;
64
65 // At this point, we don't have a walkable last_Java_frame, so
66 // we try to glean some information out of the ucontext.
67 intptr_t* ret_sp;
68 ExtendedPC addr =
69 os::fetch_frame_from_context(uc, &ret_sp,
70 NULL /* ret_fp only used on X86 */);
71 if (addr.pc() == NULL || ret_sp == NULL) {
72 // ucontext wasn't useful
73 return false;
74 }
75
76 if (MetaspaceShared::is_in_trampoline_frame(addr.pc())) {
77 // In the middle of a trampoline call. Bail out for safety.
78 // This happens rarely so shouldn't affect profiling.
79 return false;
80 }
81
82 // we were running Java code when SIGPROF came in
83 if (isInJava) {
84 // If we have a last_Java_sp, then the SIGPROF signal caught us
85 // right when we were transitioning from _thread_in_Java to a new
86 // JavaThreadState. We use last_Java_sp instead of the sp from
87 // the ucontext since it should be more reliable.
88 if (jt->has_last_Java_frame()) {
89 ret_sp = jt->last_Java_sp();
90 }
91 // Implied else: we don't have a last_Java_sp so we use what we
92 // got from the ucontext.
93
94 frame ret_frame(ret_sp, frame::unpatchable, addr.pc());
95 if (!ret_frame.safe_for_sender(jt)) {
96 // nothing else to try if the frame isn't good
97 return false;
98 }
99 *fr_addr = ret_frame;
100 return true;
101 }
102
103 // At this point, we know we weren't running Java code. We might
104 // have a last_Java_sp, but we don't have a walkable frame.
105 // However, we might still be able to construct something useful
106 // if the thread was running native code.
107 if (jt->has_last_Java_frame()) {
108 assert(!jt->frame_anchor()->walkable(), "case covered above");
109
110 if (jt->thread_state() == _thread_in_native) {
111 frame ret_frame(jt->last_Java_sp(), frame::unpatchable, addr.pc());
112 if (!ret_frame.safe_for_sender(jt)) {
113 // nothing else to try if the frame isn't good
114 return false;
115 }
116 *fr_addr = ret_frame;
117 return true;
118 }
119 }
120
121 // nothing else to try
122 return false;
123 }
124
125 void JavaThread::cache_global_variables() { }
126