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#if defined(__FreeBSD__)
54#include <sys/param.h>
55
56#endif
57
58#include "base/atomicio.hh"
59#include "base/cprintf.hh"
60#include "base/logging.hh"
61#include "sim/async.hh"
62#include "sim/backtrace.hh"
63#include "sim/core.hh"
64#include "sim/eventq.hh"
65
66using namespace std;
67
68// Use an separate stack for fatal signal handlers
69static uint8_t fatalSigStack[2 * SIGSTKSZ];
70
71static bool
72setupAltStack()
73{
74    stack_t stack;
75#if defined(__FreeBSD__) && (__FreeBSD_version < 1100097)
76    stack.ss_sp = (char *)fatalSigStack;
77#else
78    stack.ss_sp = fatalSigStack;
79#endif
80    stack.ss_size = sizeof(fatalSigStack);
81    stack.ss_flags = 0;
82
83    return sigaltstack(&stack, NULL) == 0;
84}
85
86static void
87installSignalHandler(int signal, void (*handler)(int sigtype),
88                     int flags = SA_RESTART)
89{
90    struct sigaction sa;
91
92    memset(&sa, 0, sizeof(sa));
93    sigemptyset(&sa.sa_mask);
94    sa.sa_handler = handler;
95    sa.sa_flags = flags;
96
97    if (sigaction(signal, &sa, NULL) == -1)
98        panic("Failed to setup handler for signal %i\n", signal);
99}
100
101static void
102raiseFatalSignal(int signo)
103{
104    // The signal handler should have been reset and unmasked (it was
105    // registered with SA_RESETHAND | SA_NODEFER), just raise the
106    // signal again to invoke the default handler.
107    pthread_kill(pthread_self(), signo);
108
109    // Something is really wrong if the process is alive at this
110    // point, manually try to exit it.
111    STATIC_ERR("Failed to execute default signal handler!\n");
112    _exit(127);
113}
114
115/// Stats signal handler.
116void
117dumpStatsHandler(int sigtype)
118{
119    async_event = true;
120    async_statdump = true;
121    /* Wake up some event queue to handle event */
122    getEventQueue(0)->wakeup();
123}
124
125void
126dumprstStatsHandler(int sigtype)
127{
128    async_event = true;
129    async_statdump = true;
130    async_statreset = true;
131    /* Wake up some event queue to handle event */
132    getEventQueue(0)->wakeup();
133}
134
135/// Exit signal handler.
136void
137exitNowHandler(int sigtype)
138{
139    async_event = true;
140    async_exit = true;
141    /* Wake up some event queue to handle event */
142    getEventQueue(0)->wakeup();
143}
144
145/// Abort signal handler.
146void
147abortHandler(int sigtype)
148{
149    const EventQueue *const eq(curEventQueue());
150    if (eq) {
151        ccprintf(cerr, "Program aborted at tick %llu\n", eq->getCurTick());
152    } else {
153        STATIC_ERR("Program aborted\n\n");
154    }
155
156    print_backtrace();
157    raiseFatalSignal(sigtype);
158}
159
160/// Segmentation fault signal handler.
161static void
162segvHandler(int sigtype)
163{
164    STATIC_ERR("gem5 has encountered a segmentation fault!\n\n");
165
166    print_backtrace();
167    raiseFatalSignal(SIGSEGV);
168}
169
170// Handle SIGIO
171static void
172ioHandler(int sigtype)
173{
174    async_event = true;
175    async_io = true;
176    /* Wake up some event queue to handle event */
177    getEventQueue(0)->wakeup();
178}
179
180/*
181 * M5 can do several special things when various signals are sent.
182 * None are mandatory.
183 */
184void
185initSignals()
186{
187    // Floating point exceptions may happen on misspeculated paths, so
188    // ignore them
189    signal(SIGFPE, SIG_IGN);
190
191    // Dump intermediate stats
192    installSignalHandler(SIGUSR1, dumpStatsHandler);
193
194    // Dump intermediate stats and reset them
195    installSignalHandler(SIGUSR2, dumprstStatsHandler);
196
197    // Exit cleanly on Interrupt (Ctrl-C)
198    installSignalHandler(SIGINT, exitNowHandler);
199
200    // Print the current cycle number and a backtrace on abort. Make
201    // sure the signal is unmasked and the handler reset when a signal
202    // is delivered to be able to invoke the default handler.
203    installSignalHandler(SIGABRT, abortHandler, SA_RESETHAND | SA_NODEFER);
204
205    // Setup a SIGSEGV handler with a private stack
206    if (setupAltStack()) {
207        installSignalHandler(SIGSEGV, segvHandler,
208                             SA_RESETHAND | SA_NODEFER | SA_ONSTACK);
209    } else {
210        warn("Failed to setup stack for SIGSEGV handler, "
211             "using default signal handler.\n");
212    }
213
214    // Install a SIGIO handler to handle asynchronous file IO. See the
215    // PollQueue class.
216    installSignalHandler(SIGIO, ioHandler);
217}
218
219