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 "sim/async.hh"
  56 #include "sim/backtrace.hh"
  57 #include "sim/core.hh"
  58 #include "sim/eventq.hh"
  59
  60 using namespace std;
  61
  62 // Use an separate stack for fatal signal handlers
  63 static uint8_t fatalSigStack[2 * SIGSTKSZ];
  64
  65 static bool
  66 setupAltStack()
  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
  76 static void
  77 installSignalHandler(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
  91 static void
  92 raiseFatalSignal(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.
 106 void
 107 dumpStatsHandler(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
 115 void
 116 dumprstStatsHandler(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.
 126 void
 127 exitNowHandler(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.
 136 void
 137 abortHandler(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.
 151 static void
 152 segvHandler(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
 161 static void
 162 ioHandler(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  */
 174 void
 175 initSignals()
 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