src/sim/init_signals.cc

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