PERFORCE change 74128 for review

[John Baldwin]

http://perforce.freebsd.org/chv.cgi?CH=74128

Change 74128 by jhb at jhb_slimer on 2005/03/30 22:03:59

	Fixes for SMP kernels for atomic_ptr() changes.

Affected files ...

.. //depot/projects/smpng/sys/kern/kern_mutex.c#95 edit
.. //depot/projects/smpng/sys/kern/kern_shutdown.c#56 edit

Differences ...

==== //depot/projects/smpng/sys/kern/kern_mutex.c#95 (text+ko) ====

@@ -599,7 +599,7 @@
 		if (apic_hack)
 			APIC_IPI_SPINWAIT_ENTER();
 #endif
-		while (m->mtx_lock != (void *)MTX_UNOWNED) {
+		while (m->mtx_lock != MTX_UNOWNED) {
 			if (i++ < 10000000) {
 				cpu_spinwait();
 				continue;

==== //depot/projects/smpng/sys/kern/kern_shutdown.c#56 (text+ko) ====

@@ -475,7 +475,7 @@
 }
 
 #ifdef SMP
-static volatile void *panic_thread = NULL;
+static volatile uintptr_t panic_thread;
 #endif
 
 /*
@@ -492,17 +492,19 @@
 	int bootopt, newpanic;
 	va_list ap;
 	static char buf[256];
+#ifdef SMP
+	uintptr_t tid;
 
-#ifdef SMP
 	/*
 	 * We don't want multiple CPU's to panic at the same time, so we
 	 * use panic_thread as a simple spinlock.  We have to keep checking
 	 * panic_thread if we are spinning in case the panic on the first
 	 * CPU is canceled.
 	 */
-	if (panic_thread != td)
-		while (atomic_cmpset_ptr(&panic_thread, NULL, td) == 0)
-			while (panic_thread != NULL)
+	tid = (uintptr_t)td;
+	if (panic_thread != tid)
+		while (atomic_cmpset_ptr(&panic_thread, 0, tid) == 0)
+			while (panic_thread != 0)
 				cpu_spinwait();
 #endif
 
@@ -539,7 +541,7 @@
 	/* See if the user aborted the panic, in which case we continue. */
 	if (panicstr == NULL) {
 #ifdef SMP
-		atomic_store_rel_ptr(&panic_thread, NULL);
+		atomic_store_rel_ptr(&panic_thread, 0);
 #endif
 		return;
 	}