--- pgtable.h-orig	Tue Feb  1 14:20:49 2000
+++ pgtable.h	Tue Feb  1 14:30:09 2000
@@ -128,6 +128,7 @@
 #define _PAGE_SHARED	0
 
 #else
+
 #define _PAGE_PRESENT	0x0001	/* Page is valid */
 #define _PAGE_NO_CACHE	0x0002	/* I: cache inhibit */
 #define _PAGE_SHARED	0x0004	/* No ASID (context) compare */
@@ -136,17 +137,14 @@
  * into the TLB.
  */
 #define _PAGE_GUARDED	0x0010	/* software: guarded access */
-#define _PAGE_WRITETHRU 0x0020	/* software: use writethrough cache */
+#define _PAGE_DIRTY     0x0020	/* software: page is dirty */
 #define _PAGE_RW	0x0040	/* software: user write access allowed */
 #define _PAGE_ACCESSED	0x0080	/* software: page referenced */
 
-#define _PAGE_DIRTY	0x0100	/* C: page changed (write protect) */
+#define _PAGE_HWWRITE	0x0100	/* C: page changed (~write protect) */
 #define _PAGE_USER	0x0800	/* One of the PP bits, the other must be 0 */
 
-/* This is used to enable or disable the actual hardware write
- * protection.
- */
-#define _PAGE_HWWRITE	_PAGE_DIRTY
+#define _PAGE_WRITETHRU _PAGE_NO_CACHE	/* software: use writethrough cache */
 
 #endif /* CONFIG_8xx */
 
@@ -226,11 +224,18 @@
 #define SET_PAGE_DIR(tsk,pgdir)  \
 	((tsk)->tss.pg_tables = (unsigned long *)(pgdir))
 #else /* CONFIG_8xx */     
+/*
+ * SET_PAGE_DIR should only update M_TWB if the destination
+ * is the current task otherwise the next TLB miss could cause
+ * a disaster. -- P.C.A.
+ */
 #define SET_PAGE_DIR(tsk,pgdir)  \
  do { \
 	unsigned long __pgdir = (unsigned long)pgdir; \
 	((tsk)->tss.pg_tables = (unsigned long *)(__pgdir)); \
-	asm("mtspr %0,%1 \n\t" : : "i"(M_TWB), "r"(__pa(__pgdir))); \
+	if ((tsk) == current) { \
+		asm("mtspr %0,%1 \n\t" : : "i"(M_TWB), "r"(__pa(__pgdir))); \
+	} \
  } while (0)
 #endif /* CONFIG_8xx */