1 files changed, 20 insertions, 2 deletions

diff --git a/include/asm-s390/page.h b/include/asm-s390/page.h
index 363ea761d5ee..05ea6f172786 100644
--- a/include/asm-s390/page.h
+++ b/include/asm-s390/page.h
@@ -127,6 +127,26 @@ page_get_storage_key(unsigned long addr)
         return skey;
 }
 
+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;
+}
+
 #endif /* !__ASSEMBLY__ */
 
 /* to align the pointer to the (next) page boundary */
@@ -138,8 +158,6 @@ page_get_storage_key(unsigned long addr)
 #define __va(x)                 (void *)(unsigned long)(x)
 #define virt_to_page(kaddr)     pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 #define page_to_phys(page)      (page_to_pfn(page) << PAGE_SHIFT)
-
-#define pfn_valid(pfn)          ((pfn) < max_mapnr)
 #define virt_addr_valid(kaddr)  pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
 
 #define VM_DATA_DEFAULT_FLAGS   (VM_READ | VM_WRITE | VM_EXEC | \