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.

32 files changed, 79 insertions, 579 deletions

diff --git a/sys/src/9/alphapc/dat.h b/sys/src/9/alphapc/dat.h
index 5257a291e..250d607e0 100644
--- a/sys/src/9/alphapc/dat.h
+++ b/sys/src/9/alphapc/dat.h
@@ -186,7 +186,6 @@ struct
 	Lock;
 	short	machs;
 	short	exiting;
-	short	ispanic;
 }active;
 
 /*
diff --git a/sys/src/9/alphapc/main.c b/sys/src/9/alphapc/main.c
index ac123ea9f..9175c2627 100644
--- a/sys/src/9/alphapc/main.c
+++ b/sys/src/9/alphapc/main.c
@@ -308,123 +308,21 @@ setupboot(int halt)
 	cpu->state |= (halt? Cpuhaltstayhalted: Cpuhaltwarmboot);
 }
 
-/* from ../pc */
-static void
-shutdown(int ispanic)
-{
-	int ms, once;
-
-	lock(&active);
-	if(ispanic)
-		active.ispanic = ispanic;
-	else if(m->machno == 0 && (active.machs & (1<<m->machno)) == 0)
-		active.ispanic = 0;
-	once = active.machs & (1<<m->machno);
-	active.machs &= ~(1<<m->machno);
-	active.exiting = 1;
-	unlock(&active);
-
-	if(once)
-		print("cpu%d: exiting\n", m->machno);
-	spllo();
-	for(ms = 5*1000; ms > 0; ms -= TK2MS(2)){
-		delay(TK2MS(2));
-		if(active.machs == 0 && consactive() == 0)
-			break;
-	}
-
-	if(active.ispanic && m->machno == 0) {
-		if(cpuserver)
-			delay(10000);
-		else
-			for (;;)
-				continue;
-	} else
-		delay(1000);
-}
-
-/* from ../pc: */
 void
-reboot(void *entry, void *code, ulong size)
+reboot(void *, void *, ulong)
 {
-	// writeconf();		// pass kernel environment to next kernel
-	shutdown(0);
-
-	/*
-	 * should be the only processor running now
-	 */
-	print("shutting down...\n");
-	delay(200);
-
-	splhi();
-
-	/* turn off buffered serial console */
-	serialoq = nil;
-
-	/* shutdown devices */
-	chandevshutdown();
-
-#ifdef FUTURE
-{
-	ulong *pdb;
-	/*
-	 * Modify the machine page table to directly map the low 4MB of memory
-	 * This allows the reboot code to turn off the page mapping
-	 */
-	pdb = m->pdb;
-	pdb[PDX(0)] = pdb[PDX(KZERO)];
-	mmuflushtlb(PADDR(pdb));
-}
-	/* setup reboot trampoline function */
-{
-	void (*f)(ulong, ulong, ulong) = (void*)REBOOTADDR;
-
-	memmove(f, rebootcode, sizeof(rebootcode));
-#else
-	USED(entry, code, size);
-#endif
-
-	print("rebooting...\n");
-#ifdef FUTURE
-	/* off we go - never to return */
-	(*f)(PADDR(entry), PADDR(code), size);
-}
-#endif
-	setupboot(0);		// reboot, don't halt
-	exit(0);
 }
 
 void
-exit(int ispanic)
+exit(int)
 {
-	canlock(&active);
-	active.machs &= ~(1<<m->machno);
-	active.exiting = 1;
-	unlock(&active);
-
-	spllo();
-	print("cpu %d exiting\n", m->machno);
-	do
-		delay(100);
-	while(consactive());
-
+	cpushutdown();
 	splhi();
-	delay(1000);	/* give serial fifo time to finish flushing */
-	if (getconf("*debug") != nil) {
-		USED(ispanic);
-		delay(60*1000);		/* give us time to read the screen */
-	}
 	if(arch->coredetach)
 		arch->coredetach();
 	setupboot(1);			// set up to halt
-	for (; ; )
+	for (;;)
 		firmware();
-
-	// on PC is just:
-	//if (0) {
-	//	shutdown(ispanic);
-	//	arch->reset();
-	//}
 }
 
 void
diff --git a/sys/src/9/bcm/dat.h b/sys/src/9/bcm/dat.h
index cb860a6fa..76d4012c3 100644
--- a/sys/src/9/bcm/dat.h
+++ b/sys/src/9/bcm/dat.h
@@ -225,7 +225,6 @@ struct
 	Lock;
 	int	machs;			/* bitmap of active CPUs */
 	int	exiting;		/* shutdown */
-	int	ispanic;		/* shutdown in response to a panic */
 }active;
 
 extern register Mach* m;			/* R10 */
diff --git a/sys/src/9/bcm/main.c b/sys/src/9/bcm/main.c
index 1746a5279..a39637a21 100644
--- a/sys/src/9/bcm/main.c
+++ b/sys/src/9/bcm/main.c
@@ -522,39 +522,13 @@ confinit(void)
 
 }
 
-static void
-shutdown(int ispanic)
-{
-	int ms, once;
-
-	lock(&active);
-	if(ispanic)
-		active.ispanic = ispanic;
-	else if(m->machno == 0 && (active.machs & (1<<m->machno)) == 0)
-		active.ispanic = 0;
-	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);
-	spllo();
-	for(ms = 5*1000; ms > 0; ms -= TK2MS(2)){
-		delay(TK2MS(2));
-		if(active.machs == 0 && consactive() == 0)
-			break;
-	}
-	delay(1000);
-}
-
 /*
  *  exit kernel either on a panic or user request
  */
 void
-exit(int code)
+exit(int)
 {
-	shutdown(code);
+	cpushutdown();
 	splfhi();
 	archreboot();
 }
@@ -579,17 +553,8 @@ reboot(void *entry, void *code, ulong size)
 {
 	void (*f)(ulong, ulong, ulong);
 
-	print("starting reboot...");
 	writeconf();
-	shutdown(0);
-
-	/*
-	 * should be the only processor running now
-	 */
-
-	print("reboot entry %#lux code %#lux size %ld\n",
-		PADDR(entry), PADDR(code), size);
-	delay(100);
+	cpushutdown();
 
 	/* turn off buffered serial console */
 	serialoq = nil;
@@ -612,10 +577,6 @@ reboot(void *entry, void *code, ulong size)
 
 	/* off we go - never to return */
 	(*f)(PADDR(entry), PADDR(code), size);
-
-	iprint("loaded kernel returned!\n");
-	delay(1000);
-	archreboot();
 }
 
 int
diff --git a/sys/src/9/bitsy/dat.h b/sys/src/9/bitsy/dat.h
index a2e8b410a..6b5d190a7 100644
--- a/sys/src/9/bitsy/dat.h
+++ b/sys/src/9/bitsy/dat.h
@@ -180,7 +180,6 @@ struct
 	Lock;
 	int	machs;			/* bitmap of active CPUs */
 	int	exiting;		/* shutdown */
-	int	ispanic;		/* shutdown in response to a panic */
 }active;
 
 #define	MACHP(n)	((Mach *)(MACHADDR+(n)*BY2PG))
diff --git a/sys/src/9/bitsy/main.c b/sys/src/9/bitsy/main.c
index 03f496286..203428e73 100644
--- a/sys/src/9/bitsy/main.c
+++ b/sys/src/9/bitsy/main.c
@@ -56,7 +56,6 @@ main(void)
 void
 reboot(void*, void*, ulong)
 {
-	exit(0);
 }
 
 
@@ -64,13 +63,12 @@ reboot(void*, void*, ulong)
  *  exit kernel either on a panic or user request
  */
 void
-exit(int ispanic)
+exit(int)
 {
 	void (*f)(void);
 
-	USED(ispanic);
-	delay(1000);
-
+	cpushutdown();
+	splhi();
 	iprint("it's a wonderful day to die\n");
 	cacheflush();
 	mmuinvalidate();
diff --git a/sys/src/9/kw/dat.h b/sys/src/9/kw/dat.h
index f0327bb6a..a6623abac 100644
--- a/sys/src/9/kw/dat.h
+++ b/sys/src/9/kw/dat.h
@@ -196,7 +196,6 @@ struct
 	Lock;
 	int	machs;			/* bitmap of active CPUs */
 	int	exiting;		/* shutdown */
-	int	ispanic;		/* shutdown in response to a panic */
 }active;
 
 enum {
diff --git a/sys/src/9/kw/main.c b/sys/src/9/kw/main.c
index 8b2080ef7..e938660b3 100644
--- a/sys/src/9/kw/main.c
+++ b/sys/src/9/kw/main.c
@@ -355,39 +355,13 @@ machinit(void)
 	up = nil;
 }
 
-static void
-shutdown(int ispanic)
-{
-	int ms, once;
-
-	lock(&active);
-	if(ispanic)
-		active.ispanic = ispanic;
-	else if(m->machno == 0 && (active.machs & (1<<m->machno)) == 0)
-		active.ispanic = 0;
-	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);
-	spllo();
-	for(ms = 5*1000; ms > 0; ms -= TK2MS(2)){
-		delay(TK2MS(2));
-		if(active.machs == 0 && consactive() == 0)
-			break;
-	}
-	delay(1000);
-}
-
 /*
  *  exit kernel either on a panic or user request
  */
 void
-exit(int code)
+exit(int)
 {
-	shutdown(code);
+	cpushutdown();
 	splhi();
 	archreboot();
 }
@@ -401,17 +375,8 @@ reboot(void *entry, void *code, ulong size)
 {
 	void (*f)(ulong, ulong, ulong);
 
-	iprint("starting reboot...");
 	writeconf();
-	
-	shutdown(0);
-
-	/*
-	 * should be the only processor running now
-	 */
-
-	print("shutting down...\n");
-	delay(200);
+	cpushutdown();
 
 	/* turn off buffered serial console */
 	serialoq = nil;
@@ -430,19 +395,10 @@ reboot(void *entry, void *code, ulong size)
 	cacheuwbinv();
 	l2cacheuwb();
 
-	print("rebooting...");
-	iprint("entry %#lux code %#lux size %ld\n",
-		PADDR(entry), PADDR(code), size);
-	delay(100);		/* wait for uart to quiesce */
-
 	/* off we go - never to return */
 	cacheuwbinv();
 	l2cacheuwb();
 	(*f)(PADDR(entry), PADDR(code), size);
-
-	iprint("loaded kernel returned!\n");
-	delay(1000);
-	archreboot();
 }
 
 /*
diff --git a/sys/src/9/mtx/dat.h b/sys/src/9/mtx/dat.h
index 294bca8c5..4e3c7414d 100644
--- a/sys/src/9/mtx/dat.h
+++ b/sys/src/9/mtx/dat.h
@@ -183,7 +183,6 @@ struct
 	Lock;
 	short	machs;
 	short	exiting;
-	short	ispanic;
 }active;
 
 /*
diff --git a/sys/src/9/mtx/main.c b/sys/src/9/mtx/main.c
index 491580101..f3c5a1568 100644
--- a/sys/src/9/mtx/main.c
+++ b/sys/src/9/mtx/main.c
@@ -211,42 +211,12 @@ userinit(void)
 void
 reboot(void*, void*, ulong)
 {
-	exit(0);
 }
 
 void
-exit(int ispanic)
+exit(int)
 {
-	int ms, once;
-
-	lock(&active);
-	if(ispanic)
-		active.ispanic = ispanic;
-	else if(m->machno == 0 && (active.machs & (1<<m->machno)) == 0)
-		active.ispanic = 0;
-	once = active.machs & (1<<m->machno);
-	active.machs &= ~(1<<m->machno);
-	active.exiting = 1;
-	unlock(&active);
-
-	if(once)
-		print("cpu%d: exiting\n", m->machno);
-	spllo();
-	for(ms = 5*1000; ms > 0; ms -= TK2MS(2)){
-		delay(TK2MS(2));
-		if(active.machs == 0 && consactive() == 0)
-			break;
-	}
-
-	if(active.ispanic && m->machno == 0){
-		if(cpuserver)
-			delay(10000);
-		else if(conf.monitor)
-			for(;;);
-	}
-	else
-		delay(1000);
-
+	cpushutdown();
 	watchreset();
 }
 
diff --git a/sys/src/9/omap/dat.h b/sys/src/9/omap/dat.h
index 6ed388c15..982e18b74 100644
--- a/sys/src/9/omap/dat.h
+++ b/sys/src/9/omap/dat.h
@@ -218,7 +218,6 @@ struct
 	Lock;
 	int	machs;			/* bitmap of active CPUs */
 	int	exiting;		/* shutdown */
-	int	ispanic;		/* shutdown in response to a panic */
 }active;
 
 extern register Mach* m;			/* R10 */
diff --git a/sys/src/9/omap/main.c b/sys/src/9/omap/main.c
index 818da7276..42ce8ba5a 100644
--- a/sys/src/9/omap/main.c
+++ b/sys/src/9/omap/main.c
@@ -301,39 +301,13 @@ machinit(void)
 	up = nil;
 }
 
-static void
-shutdown(int ispanic)
-{
-	int ms, once;
-
-	lock(&active);
-	if(ispanic)
-		active.ispanic = ispanic;
-	else if(m->machno == 0 && (active.machs & (1<<m->machno)) == 0)
-		active.ispanic = 0;
-	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);
-	spllo();
-	for(ms = 5*1000; ms > 0; ms -= TK2MS(2)){
-		delay(TK2MS(2));
-		if(active.machs == 0 && consactive() == 0)
-			break;
-	}
-	delay(1000);
-}
-
 /*
  *  exit kernel either on a panic or user request
  */
 void
-exit(int code)
+exit(int)
 {
-	shutdown(code);
+	cpushutdown();
 	splhi();
 	archreboot();
 }
@@ -380,17 +354,8 @@ reboot(void *entry, void *code, ulong size)
 {
 	void (*f)(ulong, ulong, ulong);
 
-	print("starting reboot...");
 	writeconf();
-	shutdown(0);
-
-	/*
-	 * should be the only processor running now
-	 */
-
-	print("reboot entry %#lux code %#lux size %ld\n",
-		PADDR(entry), PADDR(code), size);
-	delay(100);
+	cpushutdown();
 
 	/* turn off buffered serial console */
 	serialoq = nil;
@@ -414,10 +379,6 @@ reboot(void *entry, void *code, ulong size)
 
 	/* off we go - never to return */
 	(*f)(PADDR(entry), PADDR(code), size);
-
-	iprint("loaded kernel returned!\n");
-	delay(1000);
-	archreboot();
 }
 
 /*
diff --git a/sys/src/9/omap4/dat.h b/sys/src/9/omap4/dat.h
index 31bf462f0..658e639d7 100644
--- a/sys/src/9/omap4/dat.h
+++ b/sys/src/9/omap4/dat.h
@@ -132,7 +132,6 @@ struct
 	Lock;
 	int	machs;			/* bitmap of active CPUs */
 	int	exiting;		/* shutdown */
-	int	ispanic;		/* shutdown in response to a panic */
 }active;
 
 extern Mach *m;
diff --git a/sys/src/9/pc/dat.h b/sys/src/9/pc/dat.h
index 8bcc5053a..19b7dfae2 100644
--- a/sys/src/9/pc/dat.h
+++ b/sys/src/9/pc/dat.h
@@ -272,7 +272,6 @@ struct
 	Lock;
 	int	machs;			/* bitmap of active CPUs */
 	int	exiting;		/* shutdown */
-	int	ispanic;		/* shutdown in response to a panic */
 	int	thunderbirdsarego;	/* lets the added processors continue to schedinit */
 }active;
 
diff --git a/sys/src/9/pc/main.c b/sys/src/9/pc/main.c
index 6672717c2..6d8341997 100644
--- a/sys/src/9/pc/main.c
+++ b/sys/src/9/pc/main.c
@@ -163,7 +163,6 @@ main(void)
 		pcimatch(0, 0, 0);
 	}else
 		links();
-	conf.monitor = 1;
 	chandevreset();
 	pageinit();
 	swapinit();
@@ -890,50 +889,6 @@ procsave(Proc *p)
 	mmuflushtlb(PADDR(m->pdb));
 }
 
-static void
-shutdown(int ispanic)
-{
-	int ms, once;
-
-	lock(&active);
-	if(ispanic)
-		active.ispanic = ispanic;
-	else if(m->machno == 0 && (active.machs & (1<<m->machno)) == 0)
-		active.ispanic = 0;
-	once = active.machs & (1<<m->machno);
-	/*
-	 * setting exiting will make hzclock() on each processor call exit(0),
-	 * which calls shutdown(0) and arch->reset(), which on mp systems calls
-	 * mpshutdown(), from which there is no return: the processor is idled
-	 * or initiates a reboot.  clearing our bit in machs avoids calling
-	 * exit(0) from hzclock() on this processor.
-	 */
-	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;
-	}
-
-	if(active.ispanic){
-		if(!cpuserver)
-			for(;;)
-				halt();
-		if(getconf("*debug"))
-			delay(5*60*1000);
-		else
-			delay(10000);
-	}
-}
-
 void
 reboot(void *entry, void *code, ulong size)
 {
@@ -952,10 +907,7 @@ reboot(void *entry, void *code, ulong size)
 		procwired(up, 0);
 		sched();
 	}
-	shutdown(0);
-
-	iprint("shutting down...\n");
-	delay(200);
+	cpushutdown();
 
 	splhi();
 
@@ -985,8 +937,8 @@ reboot(void *entry, void *code, ulong size)
 
 
 void
-exit(int ispanic)
+exit(int)
 {
-	shutdown(ispanic);
+	cpushutdown();
 	arch->reset();
 }
diff --git a/sys/src/9/pc/screen.c b/sys/src/9/pc/screen.c
index 4ff7a9485..c74d2da71 100644
--- a/sys/src/9/pc/screen.c
+++ b/sys/src/9/pc/screen.c
@@ -664,6 +664,8 @@ bootscreeninit(void)
 	scr->cur = &swcursor;
 	scr->cur->enable(scr);
 	cursoron();
+
+	conf.monitor = 1;
 }
 
 /*
diff --git a/sys/src/9/pc64/dat.h b/sys/src/9/pc64/dat.h
index 538a74da0..5558f331a 100644
--- a/sys/src/9/pc64/dat.h
+++ b/sys/src/9/pc64/dat.h
@@ -235,7 +235,6 @@ struct
 	Lock;
 	int	machs;			/* bitmap of active CPUs */
 	int	exiting;		/* shutdown */
-	int	ispanic;		/* shutdown in response to a panic */
 	int	thunderbirdsarego;	/* lets the added processors continue to schedinit */
 }active;
 
diff --git a/sys/src/9/pc64/main.c b/sys/src/9/pc64/main.c
index 8695b6ea3..4805bcc9e 100644
--- a/sys/src/9/pc64/main.c
+++ b/sys/src/9/pc64/main.c
@@ -512,7 +512,6 @@ main()
 		pcimatch(0, 0, 0);
 	}else
 		links();
-	conf.monitor = 1;
 	chandevreset();
 	preallocpages();
 	pageinit();
@@ -522,54 +521,10 @@ main()
 	schedinit();
 }
 
-static void
-shutdown(int ispanic)
-{
-	int ms, once;
-
-	lock(&active);
-	if(ispanic)
-		active.ispanic = ispanic;
-	else if(m->machno == 0 && (active.machs & (1<<m->machno)) == 0)
-		active.ispanic = 0;
-	once = active.machs & (1<<m->machno);
-	/*
-	 * setting exiting will make hzclock() on each processor call exit(0),
-	 * which calls shutdown(0) and arch->reset(), which on mp systems calls
-	 * mpshutdown(), from which there is no return: the processor is idled
-	 * or initiates a reboot.  clearing our bit in machs avoids calling
-	 * exit(0) from hzclock() on this processor.
-	 */
-	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;
-	}
-
-	if(active.ispanic){
-		if(!cpuserver)
-			for(;;)
-				halt();
-		if(getconf("*debug"))
-			delay(5*60*1000);
-		else
-			delay(10000);
-	}
-}
-
 void
-exit(int ispanic)
+exit(int)
 {
-	shutdown(ispanic);
+	cpushutdown();
 	arch->reset();
 }
 
@@ -590,10 +545,7 @@ reboot(void *entry, void *code, ulong size)
 		procwired(up, 0);
 		sched();
 	}
-	shutdown(0);
-
-	iprint("shutting down...\n");
-	delay(200);
+	cpushutdown();
 
 	splhi();
 
diff --git a/sys/src/9/port/allocb.c b/sys/src/9/port/allocb.c
index 00af00e4d..3949680cc 100644
--- a/sys/src/9/port/allocb.c
+++ b/sys/src/9/port/allocb.c
@@ -86,10 +86,8 @@ iallocb(int size)
 
 	if(ialloc.bytes > conf.ialloc){
 		if((m1++%10000)==0){
-			if(mp++ > 1000){
-				active.exiting = 1;
-				exit(0);
-			}
+			if(mp++ > 1000)
+				panic("iallocb: out of memory");
 			iprint("iallocb: limited %lud/%lud\n",
 				ialloc.bytes, conf.ialloc);
 		}
@@ -98,10 +96,8 @@ iallocb(int size)
 
 	if((b = _allocb(size)) == nil){
 		if((m2++%10000)==0){
-			if(mp++ > 1000){
-				active.exiting = 1;
-				exit(0);
-			}
+			if(mp++ > 1000)
+				panic("iallocb: out of memory");
 			iprint("iallocb: no memory %lud/%lud\n",
 				ialloc.bytes, conf.ialloc);
 		}
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;
+	}
+}
diff --git a/sys/src/9/port/portfns.h b/sys/src/9/port/portfns.h
index 4944b9285..ffda16d23 100644
--- a/sys/src/9/port/portfns.h
+++ b/sys/src/9/port/portfns.h
@@ -41,6 +41,7 @@ int		cmount(Chan**, Chan*, int, char*);
 void		confinit(void);
 int		consactive(void);
 void		(*consdebug)(void);
+void		cpushutdown(void);
 void		copen(Chan*);
 void		cclunk(Chan*);
 Block*		concatblock(Block*);
diff --git a/sys/src/9/port/rebootcmd.c b/sys/src/9/port/rebootcmd.c
index 537c4e7cf..fc5186cf2 100644
--- a/sys/src/9/port/rebootcmd.c
+++ b/sys/src/9/port/rebootcmd.c
@@ -103,6 +103,5 @@ rebootcmd(int argc, char *argv[])
 	setbootcmd(argc-1, argv+1);
 
 	reboot((void*)entry, p, size);
-
-	panic("return from reboot!");
+	error(Egreg);
 }
diff --git a/sys/src/9/port/ucallocb.c b/sys/src/9/port/ucallocb.c
index 126733d9a..410aa62e8 100644
--- a/sys/src/9/port/ucallocb.c
+++ b/sys/src/9/port/ucallocb.c
@@ -78,24 +78,10 @@ uciallocb(int size)
 	Block *b;
 	static int m1, m2, mp;
 
-	if(0 && ucialloc.bytes > conf.ialloc){
-		if((m1++%10000)==0){
-			if(mp++ > 1000){
-				active.exiting = 1;
-				exit(0);
-			}
-			iprint("uciallocb: limited %lud/%lud\n",
-				ucialloc.bytes, conf.ialloc);
-		}
-		return nil;
-	}
-
 	if((b = _ucallocb(size)) == nil){
 		if(0 && (m2++%10000)==0){
-			if(mp++ > 1000){
-				active.exiting = 1;
-				exit(0);
-			}
+			if(mp++ > 1000)
+				panic("uciallocb: out of memory");
 			iprint("uciallocb: no memory %lud/%lud\n",
 				ucialloc.bytes, conf.ialloc);
 		}
diff --git a/sys/src/9/ppc/dat.h b/sys/src/9/ppc/dat.h
index f92367764..d10559f01 100644
--- a/sys/src/9/ppc/dat.h
+++ b/sys/src/9/ppc/dat.h
@@ -191,7 +191,6 @@ struct
 	Lock;
 	short	machs;
 	short	exiting;
-	short	ispanic;
 }active;
 
 /*
diff --git a/sys/src/9/ppc/main.c b/sys/src/9/ppc/main.c
index e0badeb57..5d2a1765b 100644
--- a/sys/src/9/ppc/main.c
+++ b/sys/src/9/ppc/main.c
@@ -243,38 +243,10 @@ userinit(void)
 }
 
 void
-exit(int ispanic)
+exit(int)
 {
-	int ms, once;
-
-	lock(&active);
-	if(ispanic)
-		active.ispanic = ispanic;
-	else if(m->machno == 0 && (active.machs & (1<<m->machno)) == 0)
-		active.ispanic = 0;
-	once = active.machs & (1<<m->machno);
-	active.machs &= ~(1<<m->machno);
-	active.exiting = 1;
-	unlock(&active);
-
-	if(once)
-		print("cpu%d: exiting\n", m->machno);
-	spllo();
-	for(ms = 5*1000; ms > 0; ms -= TK2MS(2)){
-		delay(TK2MS(2));
-		if(active.machs == 0 && consactive() == 0)
-			break;
-	}
-
-	if(active.ispanic && m->machno == 0){
-		if(cpuserver)
-			delay(10000);
-		else if(conf.monitor)
-			for(;;);
-	}
-	else
-		delay(1000);
-
+	cpushutdown();
+	for(;;) idlehands();
 }
 
 /*
@@ -424,8 +396,6 @@ confinit(void)
 		 */
 		imagmem->maxsize = kpages;
 	}
-
-//	conf.monitor = 1;	/* BUG */
 }
 
 static int
diff --git a/sys/src/9/sgi/dat.h b/sys/src/9/sgi/dat.h
index b0e47a6cb..771b755ce 100644
--- a/sys/src/9/sgi/dat.h
+++ b/sys/src/9/sgi/dat.h
@@ -206,7 +206,6 @@ struct
 	Lock;
 	long	machs;		/* bitmap of processors */
 	short	exiting;
-	int	ispanic;
 }active;
 
 extern register Mach	*m;
diff --git a/sys/src/9/sgi/main.c b/sys/src/9/sgi/main.c
index 086ab4fb2..08c6c85b8 100644
--- a/sys/src/9/sgi/main.c
+++ b/sys/src/9/sgi/main.c
@@ -372,10 +372,10 @@ userinit(void)
 }
 
 void
-exit(int ispanic)
+exit(int)
 {
+	cpushutdown();
 	splhi();
-	while(ispanic);
 	arcs(0x18);	/* reboot */
 }
 
diff --git a/sys/src/9/teg2/dat.h b/sys/src/9/teg2/dat.h
index 83420dfbd..80068975c 100644
--- a/sys/src/9/teg2/dat.h
+++ b/sys/src/9/teg2/dat.h
@@ -250,7 +250,6 @@ struct
 	int	wfi;			/* bitmap of CPUs in WFI state */
 	int	stopped;		/* bitmap of CPUs stopped */
 	int	exiting;		/* shutdown */
-	int	ispanic;		/* shutdown in response to a panic */
 	int	thunderbirdsarego;	/* lets the added processors continue to schedinit */
 }active;
 
diff --git a/sys/src/9/teg2/main.c b/sys/src/9/teg2/main.c
index f5feced0a..6847f3a91 100644
--- a/sys/src/9/teg2/main.c
+++ b/sys/src/9/teg2/main.c
@@ -480,51 +480,13 @@ main(void)
 	panic("cpu%d: schedinit returned", m->machno);
 }
 
-static void
-shutdown(int ispanic)
-{
-	int ms, once;
-
-	lock(&active);
-	if(ispanic)
-		active.ispanic = ispanic;
-	else if(m->machno == 0 && (active.machs & (1<<m->machno)) == 0)
-		active.ispanic = 0;
-	once = active.machs & (1<<m->machno);
-	/*
-	 * setting exiting will make hzclock() on each processor call exit(0),
-	 * which calls shutdown(0) and idles non-bootstrap cpus and returns
-	 * on bootstrap processors (to permit a reboot).  clearing our bit
-	 * in machs avoids calling exit(0) from hzclock() on this processor.
-	 */
-	active.machs &= ~(1<<m->machno);
-	active.exiting = 1;
-	unlock(&active);
-
-	if(once) {
-		delay(m->machno*1000);		/* stagger them */
-		iprint("cpu%d: exiting\n", m->machno);
-	}
-	spllo();
-	if (m->machno == 0)
-		ms = 5*1000;
-	else
-		ms = 2*1000;
-	for(; ms > 0; ms -= TK2MS(2)){
-		delay(TK2MS(2));
-		if(active.machs == 0 && consactive() == 0)
-			break;
-	}
-	delay(500);
-}
-
 /*
  *  exit kernel either on a panic or user request
  */
 void
-exit(int code)
+exit(int)
 {
-	shutdown(code);
+	cpushutdown();
 	splhi();
 	if (m->machno == 0)
 		archreboot();
@@ -576,10 +538,8 @@ isaconfig(char *class, int ctlrno, ISAConf *isa)
 void
 reboot(void *entry, void *code, ulong size)
 {
-	int cpu, nmach, want, ms;
 	void (*f)(ulong, ulong, ulong);
 
-	nmach = conf.nmach;
 	writeconf();
 
 	/*
@@ -590,33 +550,12 @@ reboot(void *entry, void *code, ulong size)
 		procwired(up, 0);
 		sched();
 	}
-	if (m->machno != 0)
-		print("on cpu%d (not 0)!\n", m->machno);
-
-	/*
-	 * the other cpus could be holding locks that will never get
-	 * released (e.g., in the print path) if we put them into
-	 * reset now, so force them to shutdown gracefully first.
-	 */
-	for (want = 0, cpu = 1; cpu < navailcpus; cpu++)
-		want |= 1 << cpu;
-	active.stopped = 0;
-	shutdown(0);
-	for (ms = 15*1000; ms > 0 && active.stopped != want; ms -= 10)
-		delay(10);
-	delay(20);
-	if (active.stopped != want) {
-		for (cpu = 1; cpu < nmach; cpu++)
-			stopcpu(cpu);		/* make really sure */
-		delay(20);
-	}
+	cpushutdown();
 
 	/*
 	 * should be the only processor running now
 	 */
 	pcireset();
-//	print("reboot entry %#lux code %#lux size %ld\n",
-//		PADDR(entry), PADDR(code), size);
 
 	/* turn off buffered serial console */
 	serialoq = nil;
@@ -642,9 +581,6 @@ reboot(void *entry, void *code, ulong size)
 
 	/* off we go - never to return */
 	(*f)(PADDR(entry), PADDR(code), size);
-
-	iprint("loaded kernel returned!\n");
-	archreboot();
 }
 
 /*
diff --git a/sys/src/9/xen/main.c b/sys/src/9/xen/main.c
index 9888af3ce..33b800579 100644
--- a/sys/src/9/xen/main.c
+++ b/sys/src/9/xen/main.c
@@ -644,58 +644,13 @@ procsave(Proc *p)
 	mmuflushtlb(0);
 }
 
-static void
-shutdown(int ispanic)
-{
-	int ms, once;
-
-	lock(&active);
-	if(ispanic)
-		active.ispanic = ispanic;
-	else if(m->machno == 0 && (active.machs & (1<<m->machno)) == 0)
-		active.ispanic = 0;
-	once = active.machs & (1<<m->machno);
-	active.machs &= ~(1<<m->machno);
-	active.exiting = 1;
-	unlock(&active);
-
-	if(once)
-		print("cpu%d: exiting\n", m->machno);
-	//spllo();
-	for(ms = 5*1000; ms > 0; ms -= TK2MS(2)){
-		delay(TK2MS(2));
-		if(active.machs == 0 && consactive() == 0)
-			break;
-	}
-
-	if(getconf("*debug"))
-		delay(5*60*1000);
-
-	if(active.ispanic){
-		if(!cpuserver)
-			for(;;)
-				halt();
-		delay(10000);
-	}else
-		delay(1000);
-}
-
 void
 reboot(void *entry, void *code, ulong size)
 {
 	void (*f)(ulong, ulong, ulong);
-	//ulong *pdb;
 
 	writeconf();
-
-	shutdown(0);
-
-	/*
-	 * should be the only processor running now
-	 */
-
-	print("shutting down...\n");
-	delay(200);
+	cpushutdown();
 
 	splhi();
 
@@ -709,28 +664,19 @@ reboot(void *entry, void *code, ulong size)
 	if(entry == 0)
 		HYPERVISOR_shutdown(0);
 
-	/*
-	 * Modify the machine page table to directly map the low 4MB of memory
-	 * This allows the reboot code to turn off the page mapping
-	 */
-	//pdb = m->pdb;
-	//pdb[PDX(0)] = pdb[PDX(KZERO)];
 	mmuflushtlb(0);
 
 	/* setup reboot trampoline function */
 	f = (void*)REBOOTADDR;
 	memmove(f, rebootcode, sizeof(rebootcode));
 
-	print("rebooting...\n");
-
 	/* off we go - never to return */
 	(*f)(PADDR(entry), PADDR(code), size);
 }
 
-
 void
-exit(int ispanic)
+exit(int)
 {
-	shutdown(ispanic);
+	cpushutdown();
 	arch->reset();
 }
diff --git a/sys/src/9/zynq/dat.h b/sys/src/9/zynq/dat.h
index 2d3e681a7..4172407b4 100644
--- a/sys/src/9/zynq/dat.h
+++ b/sys/src/9/zynq/dat.h
@@ -177,7 +177,6 @@ struct
 	Lock;
 	int	machs;			/* bitmap of active CPUs */
 	int	exiting;		/* shutdown */
-	int	ispanic;		/* shutdown in response to a panic */
 }active;
 
 extern register Mach* m;			/* R10 */
diff --git a/sys/src/9/zynq/main.c b/sys/src/9/zynq/main.c
index 969bede81..91206e0a3 100644
--- a/sys/src/9/zynq/main.c
+++ b/sys/src/9/zynq/main.c
@@ -21,13 +21,13 @@ int nconf;
 void
 exit(int)
 {
-	NOPE
+	cpushutdown();
+	for(;;) idlehands();
 }
 
 void
 reboot(void *, void *, ulong)
 {
-	NOPE
 }
 
 void