+extern unsigned long max_pfn;
+
+static inline int pfn_valid(unsigned long pfn)
+{
+ unsigned long dummy;
+ int ccode;
+
+ if (pfn >= max_pfn)
+ return 0;
+
+ asm volatile(
+ " lra %0,0(%2)\n"
+ " ipm %1\n"
+ " srl %1,28\n"
+ : "=d" (dummy), "=d" (ccode)
+ : "a" (pfn << PAGE_SHIFT)
+ : "cc");
+ return !ccode;
+}
+