3 files changed, 48 insertions, 75 deletions

diff --git a/src/base/pollevent.cc b/src/base/pollevent.cc
index cb44d8728..67e97f98f 100644
--- a/src/base/pollevent.cc
+++ b/src/base/pollevent.cc
@@ -109,7 +109,6 @@ PollQueue::PollQueue()
 
 PollQueue::~PollQueue()
 {
-    removeHandler();
     for (int i = 0; i < num_fds; i++)
         setupAsyncIO(poll_fds[0].fd, false);
 
@@ -170,7 +169,6 @@ PollQueue::schedule(PollEvent *event)
             max_size *= 2;
         } else {
             max_size = 16;
-            setupHandler();
         }
 
         poll_fds = new pollfd[max_size];
@@ -197,10 +195,6 @@ PollQueue::service()
     }
 }
 
-struct sigaction PollQueue::oldio;
-struct sigaction PollQueue::oldalrm;
-bool PollQueue::handler = false;
-
 void
 PollQueue::setupAsyncIO(int fd, bool set)
 {
@@ -221,59 +215,3 @@ PollQueue::setupAsyncIO(int fd, bool set)
     if (fcntl(fd, F_SETFL, flags) == -1)
         panic("Could not set up async IO");
 }
-
-void
-PollQueue::setupHandler()
-{
-    struct sigaction act;
-
-    act.sa_handler = handleIO;
-    sigemptyset(&act.sa_mask);
-    act.sa_flags = SA_RESTART;
-
-    if (sigaction(SIGIO, &act, &oldio) == -1)
-        panic("could not do sigaction");
-
-    act.sa_handler = handleALRM;
-    sigemptyset(&act.sa_mask);
-    act.sa_flags = SA_RESTART;
-
-    if (sigaction(SIGALRM, &act, &oldalrm) == -1)
-        panic("could not do sigaction");
-
-    alarm(1);
-
-    handler = true;
-}
-
-void
-PollQueue::removeHandler()
-{
-    if (sigaction(SIGIO, &oldio, NULL) == -1)
-        panic("could not remove handler");
-
-    if (sigaction(SIGIO, &oldalrm, NULL) == -1)
-        panic("could not remove handler");
-}
-
-void
-PollQueue::handleIO(int sig)
-{
-    if (sig != SIGIO)
-        panic("Wrong Handler");
-
-    async_event = true;
-    async_io = true;
-}
-
-void
-PollQueue::handleALRM(int sig)
-{
-    if (sig != SIGALRM)
-        panic("Wrong Handler");
-
-    async_event = true;
-    async_alarm = true;
-    alarm(1);
-}
-
diff --git a/src/base/pollevent.hh b/src/base/pollevent.hh
index b9c833c8a..5e0faa729 100644
--- a/src/base/pollevent.hh
+++ b/src/base/pollevent.hh
@@ -83,17 +83,8 @@ class PollQueue
     void schedule(PollEvent *event);
     void service();
 
-  protected:
-    static bool handler;
-    static struct sigaction oldio;
-    static struct sigaction oldalrm;
-
   public:
     static void setupAsyncIO(int fd, bool set);
-    static void handleIO(int);
-    static void handleALRM(int);
-    static void removeHandler();
-    static void setupHandler();
 };
 
 extern PollQueue pollQueue;
diff --git a/src/sim/init.cc b/src/sim/init.cc
index 0cebc417d..660fab62b 100644
--- a/src/sim/init.cc
+++ b/src/sim/init.cc
@@ -96,6 +96,37 @@ abortHandler(int sigtype)
     ccprintf(cerr, "Program aborted at cycle %d\n", curTick());
 }
 
+// Handle SIGIO
+static void
+ioHandler(int sigtype)
+{
+    async_event = true;
+    async_io = true;
+}
+
+// Handle SIGALRM
+static void
+alrmHandler(int sigtype)
+{
+    async_event = true;
+    async_alarm = true;
+    alarm(1);
+}
+
+static void
+installSignalHandler(int signal, void (*handler)(int sigtype))
+{
+    struct sigaction sa;
+
+    memset(&sa, 0, sizeof(sa));
+    sigemptyset(&sa.sa_mask);
+    sa.sa_handler = handler;
+    sa.sa_flags = SA_RESTART;
+
+    if (sigaction(signal, &sa, NULL) == -1)
+        panic("Failed to setup handler for signal %i\n", signal);
+}
+
 /*
  * M5 can do several special things when various signals are sent.
  * None are mandatory.
@@ -111,16 +142,29 @@ initSignals()
     signal(SIGTRAP, SIG_IGN);
 
     // Dump intermediate stats
-    signal(SIGUSR1, dumpStatsHandler);
+    installSignalHandler(SIGUSR1, dumpStatsHandler);
 
     // Dump intermediate stats and reset them
-    signal(SIGUSR2, dumprstStatsHandler);
+    installSignalHandler(SIGUSR2, dumprstStatsHandler);
 
     // Exit cleanly on Interrupt (Ctrl-C)
-    signal(SIGINT, exitNowHandler);
+    installSignalHandler(SIGINT, exitNowHandler);
 
     // Print out cycle number on abort
-    signal(SIGABRT, abortHandler);
+    installSignalHandler(SIGABRT, abortHandler);
+
+    // Install a SIGIO handler to handle asynchronous file IO. See the
+    // PollQueue class.
+    installSignalHandler(SIGIO, ioHandler);
+
+    // Setup an alarm handler that triggers every second. This
+    // triggers a PollQueue service just like a SIGIO. It is
+    // /probably/ used to work around a bug in the poll queue (likely
+    // a race between setting up a asynchronous IO and data becoming
+    // available), but its use isn't documented anywhere.
+    // TODO: Find out why this is needed and fix the original bug.
+    installSignalHandler(SIGALRM, alrmHandler);
+    alarm(1);
 }
 
 // The python library is totally messed up with respect to constness,