init_signals.cc revision 11235 
1/*
2 * Copyright (c) 2012, 2015 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder.  You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2000-2005 The Regents of The University of Michigan
15 * Copyright (c) 2008 The Hewlett-Packard Development Company
16 * All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions are
20 * met: redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer;
22 * redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution;
25 * neither the name of the copyright holders nor the names of its
26 * contributors may be used to endorse or promote products derived from
27 * this software without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Authors: Nathan Binkert
42 */
43
44#include "sim/init_signals.hh"
45
46#include <sys/types.h>
47#include <unistd.h>
48
49#include <csignal>
50#include <iostream>
51#include <string>
52
53#include "base/atomicio.hh"
54#include "base/cprintf.hh"
55#include "sim/async.hh"
56#include "sim/backtrace.hh"
57#include "sim/core.hh"
58#include "sim/eventq.hh"
59
60using namespace std;
61
62// Use an separate stack for fatal signal handlers
63static uint8_t fatalSigStack[2 * SIGSTKSZ];
64
65static bool
66setupAltStack()
67{
68    stack_t stack;
69    stack.ss_sp = fatalSigStack;
70    stack.ss_size = sizeof(fatalSigStack);
71    stack.ss_flags = 0;
72
73    return sigaltstack(&stack, NULL) == 0;
74}
75
76static void
77installSignalHandler(int signal, void (*handler)(int sigtype),
78                     int flags = SA_RESTART)
79{
80    struct sigaction sa;
81
82    memset(&sa, 0, sizeof(sa));
83    sigemptyset(&sa.sa_mask);
84    sa.sa_handler = handler;
85    sa.sa_flags = flags;
86
87    if (sigaction(signal, &sa, NULL) == -1)
88        panic("Failed to setup handler for signal %i\n", signal);
89}
90
91static void
92raiseFatalSignal(int signo)
93{
94    // The signal handler should have been reset and unmasked (it was
95    // registered with SA_RESETHAND | SA_NODEFER), just raise the
96    // signal again to invoke the default handler.
97    pthread_kill(pthread_self(), signo);
98
99    // Something is really wrong if the process is alive at this
100    // point, manually try to exit it.
101    STATIC_ERR("Failed to execute default signal handler!\n");
102    _exit(127);
103}
104
105/// Stats signal handler.
106void
107dumpStatsHandler(int sigtype)
108{
109    async_event = true;
110    async_statdump = true;
111    /* Wake up some event queue to handle event */
112    getEventQueue(0)->wakeup();
113}
114
115void
116dumprstStatsHandler(int sigtype)
117{
118    async_event = true;
119    async_statdump = true;
120    async_statreset = true;
121    /* Wake up some event queue to handle event */
122    getEventQueue(0)->wakeup();
123}
124
125/// Exit signal handler.
126void
127exitNowHandler(int sigtype)
128{
129    async_event = true;
130    async_exit = true;
131    /* Wake up some event queue to handle event */
132    getEventQueue(0)->wakeup();
133}
134
135/// Abort signal handler.
136void
137abortHandler(int sigtype)
138{
139    const EventQueue *const eq(curEventQueue());
140    if (eq) {
141        ccprintf(cerr, "Program aborted at tick %llu\n", eq->getCurTick());
142    } else {
143        STATIC_ERR("Program aborted\n\n");
144    }
145
146    print_backtrace();
147    raiseFatalSignal(sigtype);
148}
149
150/// Segmentation fault signal handler.
151static void
152segvHandler(int sigtype)
153{
154    STATIC_ERR("gem5 has encountered a segmentation fault!\n\n");
155
156    print_backtrace();
157    raiseFatalSignal(SIGSEGV);
158}
159
160// Handle SIGIO
161static void
162ioHandler(int sigtype)
163{
164    async_event = true;
165    async_io = true;
166    /* Wake up some event queue to handle event */
167    getEventQueue(0)->wakeup();
168}
169
170/*
171 * M5 can do several special things when various signals are sent.
172 * None are mandatory.
173 */
174void
175initSignals()
176{
177    // Floating point exceptions may happen on misspeculated paths, so
178    // ignore them
179    signal(SIGFPE, SIG_IGN);
180
181    // We use SIGTRAP sometimes for debugging
182    signal(SIGTRAP, SIG_IGN);
183
184    // Dump intermediate stats
185    installSignalHandler(SIGUSR1, dumpStatsHandler);
186
187    // Dump intermediate stats and reset them
188    installSignalHandler(SIGUSR2, dumprstStatsHandler);
189
190    // Exit cleanly on Interrupt (Ctrl-C)
191    installSignalHandler(SIGINT, exitNowHandler);
192
193    // Print the current cycle number and a backtrace on abort. Make
194    // sure the signal is unmasked and the handler reset when a signal
195    // is delivered to be able to invoke the default handler.
196    installSignalHandler(SIGABRT, abortHandler, SA_RESETHAND | SA_NODEFER);
197
198    // Setup a SIGSEGV handler with a private stack
199    if (setupAltStack()) {
200        installSignalHandler(SIGSEGV, segvHandler,
201                             SA_RESETHAND | SA_NODEFER | SA_ONSTACK);
202    } else {
203        warn("Failed to setup stack for SIGSEGV handler, "
204             "using default signal handler.\n");
205    }
206
207    // Install a SIGIO handler to handle asynchronous file IO. See the
208    // PollQueue class.
209    installSignalHandler(SIGIO, ioHandler);
210}
211
212