gem5  v21.1.0.2
init_signals.cc
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1 /*
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40  */
41 
42 #include "sim/init_signals.hh"
43 
44 #include <sys/types.h>
45 #include <unistd.h>
46 
47 #include <csignal>
48 #include <iostream>
49 #include <string>
50 
51 #if defined(__FreeBSD__)
52 #include <sys/param.h>
53 
54 #endif
55 
56 #include "base/atomicio.hh"
57 #include "base/cprintf.hh"
58 #include "base/logging.hh"
59 #include "sim/async.hh"
60 #include "sim/backtrace.hh"
61 #include "sim/eventq.hh"
62 
63 namespace gem5
64 {
65 
66 // Use an separate stack for fatal signal handlers
67 static uint8_t fatalSigStack[2 * SIGSTKSZ];
68 
69 static bool
71 {
72  stack_t stack;
73 #if defined(__FreeBSD__) && (__FreeBSD_version < 1100097)
74  stack.ss_sp = (char *)fatalSigStack;
75 #else
76  stack.ss_sp = fatalSigStack;
77 #endif
78  stack.ss_size = sizeof(fatalSigStack);
79  stack.ss_flags = 0;
80 
81  return sigaltstack(&stack, NULL) == 0;
82 }
83 
84 static void
85 installSignalHandler(int signal, void (*handler)(int sigtype),
86  int flags = SA_RESTART)
87 {
88  struct sigaction sa;
89 
90  memset(&sa, 0, sizeof(sa));
91  sigemptyset(&sa.sa_mask);
92  sa.sa_handler = handler;
93  sa.sa_flags = flags;
94 
95  if (sigaction(signal, &sa, NULL) == -1)
96  panic("Failed to setup handler for signal %i\n", signal);
97 }
98 
99 static void
101 {
102  // The signal handler should have been reset and unmasked (it was
103  // registered with SA_RESETHAND | SA_NODEFER), just raise the
104  // signal again to invoke the default handler.
105  pthread_kill(pthread_self(), signo);
106 
107  // Something is really wrong if the process is alive at this
108  // point, manually try to exit it.
109  STATIC_ERR("Failed to execute default signal handler!\n");
110  _exit(127);
111 }
112 
114 void
115 dumpStatsHandler(int sigtype)
116 {
117  async_event = true;
118  async_statdump = true;
119  /* Wake up some event queue to handle event */
120  getEventQueue(0)->wakeup();
121 }
122 
123 void
125 {
126  async_event = true;
127  async_statdump = true;
128  async_statreset = true;
129  /* Wake up some event queue to handle event */
130  getEventQueue(0)->wakeup();
131 }
132 
134 void
135 exitNowHandler(int sigtype)
136 {
137  async_event = true;
138  async_exit = true;
139  /* Wake up some event queue to handle event */
140  getEventQueue(0)->wakeup();
141 }
142 
144 void
145 abortHandler(int sigtype)
146 {
147  const EventQueue *const eq(curEventQueue());
148  if (eq) {
149  ccprintf(std::cerr, "Program aborted at tick %llu\n",
150  eq->getCurTick());
151  } else {
152  STATIC_ERR("Program aborted\n\n");
153  }
154 
155  print_backtrace();
156  raiseFatalSignal(sigtype);
157 }
158 
160 static void
161 segvHandler(int sigtype)
162 {
163  STATIC_ERR("gem5 has encountered a segmentation fault!\n\n");
164 
165  print_backtrace();
166  raiseFatalSignal(SIGSEGV);
167 }
168 
169 // Handle SIGIO
170 static void
171 ioHandler(int sigtype)
172 {
173  async_event = true;
174  async_io = true;
175  /* Wake up some event queue to handle event */
176  getEventQueue(0)->wakeup();
177 }
178 
179 /*
180  * M5 can do several special things when various signals are sent.
181  * None are mandatory.
182  */
183 void
185 {
186  // Floating point exceptions may happen on misspeculated paths, so
187  // ignore them
188  signal(SIGFPE, SIG_IGN);
189 
190  // Dump intermediate stats
192 
193  // Dump intermediate stats and reset them
195 
196  // Exit cleanly on Interrupt (Ctrl-C)
198 
199  // Print the current cycle number and a backtrace on abort. Make
200  // sure the signal is unmasked and the handler reset when a signal
201  // is delivered to be able to invoke the default handler.
202  installSignalHandler(SIGABRT, abortHandler, SA_RESETHAND | SA_NODEFER);
203 
204  // Setup a SIGSEGV handler with a private stack
205  if (setupAltStack()) {
207  SA_RESETHAND | SA_NODEFER | SA_ONSTACK);
208  } else {
209  warn("Failed to setup stack for SIGSEGV handler, "
210  "using default signal handler.\n");
211  }
212 
213  // Install a SIGIO handler to handle asynchronous file IO. See the
214  // PollQueue class.
216 }
217 
218 } // namespace gem5
gem5::abortHandler
void abortHandler(int sigtype)
Abort signal handler.
Definition: init_signals.cc:145
warn
#define warn(...)
Definition: logging.hh:245
gem5::dumprstStatsHandler
void dumprstStatsHandler(int sigtype)
Definition: init_signals.cc:124
atomicio.hh
gem5::dumpStatsHandler
void dumpStatsHandler(int sigtype)
Stats signal handler.
Definition: init_signals.cc:115
gem5::async_exit
volatile bool async_exit
Async request to exit simulator.
Definition: async.cc:35
gem5::getEventQueue
EventQueue * getEventQueue(uint32_t index)
Function for returning eventq queue for the provided index.
Definition: eventq.cc:62
gem5::segvHandler
static void segvHandler(int sigtype)
Segmentation fault signal handler.
Definition: init_signals.cc:161
gem5::async_statreset
volatile bool async_statreset
Async request to reset stats.
Definition: async.cc:34
gem5::initSignals
void initSignals()
Definition: init_signals.cc:184
gem5::raiseFatalSignal
static void raiseFatalSignal(int signo)
Definition: init_signals.cc:100
gem5::EventQueue::wakeup
virtual void wakeup(Tick when=(Tick) -1)
Function to signal that the event loop should be woken up because an event has been scheduled by an a...
Definition: eventq.hh:930
gem5::exitNowHandler
void exitNowHandler(int sigtype)
Exit signal handler.
Definition: init_signals.cc:135
gem5::installSignalHandler
static void installSignalHandler(int signal, void(*handler)(int sigtype), int flags=SA_RESTART)
Definition: init_signals.cc:85
gem5::ccprintf
void ccprintf(cp::Print &print)
Definition: cprintf.hh:130
gem5::async_statdump
volatile bool async_statdump
Async request to dump stats.
Definition: async.cc:33
STATIC_ERR
#define STATIC_ERR(m)
Statically allocate a string and write it to STDERR.
Definition: atomicio.hh:67
gem5::X86ISA::stack
Bitfield< 17, 16 > stack
Definition: misc.hh:593
gem5::EventQueue
Queue of events sorted in time order.
Definition: eventq.hh:622
cprintf.hh
gem5::async_io
volatile bool async_io
Async I/O request (SIGIO).
Definition: async.cc:36
async.hh
gem5::curEventQueue
EventQueue * curEventQueue()
Definition: eventq.hh:88
gem5::PowerISA::eq
Bitfield< 29 > eq
Definition: misc.hh:53
gem5::setupAltStack
static bool setupAltStack()
Definition: init_signals.cc:70
logging.hh
init_signals.hh
gem5::ioHandler
static void ioHandler(int sigtype)
Definition: init_signals.cc:171
gem5
Reference material can be found at the JEDEC website: UFS standard http://www.jedec....
Definition: decoder.cc:40
gem5::print_backtrace
void print_backtrace()
Print a gem5 post-mortem report.
Definition: backtrace_glibc.cc:54
gem5::fatalSigStack
static uint8_t fatalSigStack[2 *SIGSTKSZ]
Definition: init_signals.cc:67
backtrace.hh
gem5::async_event
volatile bool async_event
Some asynchronous event has happened.
Definition: async.cc:32
gem5::ArmISA::sa
Bitfield< 3 > sa
Definition: misc_types.hh:391
panic
#define panic(...)
This implements a cprintf based panic() function.
Definition: logging.hh:177
eventq.hh

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