kernel: cleanup exit()/shutdown()/reboot() code

introduce cpushutdown() function that does the common
operation of initiating shutdown, returning once all
cpu's got the message and are about to shutdown. this
avoids duplicated code which isnt really machine specific.

automatic reboot on panic only when *debug= is not set
and the machine is a cpu server or has no display,
otherwise just hang.

1 files changed, 32 insertions, 3 deletions

diff --git a/sys/src/9/port/devcons.c b/sys/src/9/port/devcons.c
index dc761f493..78f56afd1 100644
--- a/sys/src/9/port/devcons.c
+++ b/sys/src/9/port/devcons.c
@@ -260,9 +260,15 @@ panic(char *fmt, ...)
 	splx(s);
 	prflush();
 	dumpstack();
-	if(!cpuserver)
-		for(;;);
-	exit(1);
+
+	/* reboot cpu servers and headless machines when not debugging */
+	if(getconf("*debug") == nil)
+	if(cpuserver || !conf.monitor)
+		exit(1);
+
+	/* otherwise, just hang */
+	while(islo()) idlehands();
+	for(;;);
 }
 
 /* libmp at least contains a few calls to sysfatal; simulate with panic */
@@ -1038,3 +1044,26 @@ writebintime(char *buf, int n)
 	}
 	return n;
 }
+
+void
+cpushutdown(void)
+{
+	int ms, once;
+
+	lock(&active);
+	once = active.machs & (1<<m->machno);
+	active.machs &= ~(1<<m->machno);
+	active.exiting = 1;
+	unlock(&active);
+
+	if(once)
+		iprint("cpu%d: exiting\n", m->machno);
+
+	/* wait for any other processors to shutdown */
+	spllo();
+	for(ms = 5*1000; ms > 0; ms -= TK2MS(2)){
+		delay(TK2MS(2));
+		if(active.machs == 0 && consactive() == 0)
+			break;
+	}
+}