[PATCH] uml-i386: fix build breakage with CONFIG_HIGHMEM

missing helper used by arch/i386/mm/highmem.c, which is pulled
into build on that configuration.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-um/pgtable.h

@@ -408,6 +408,15 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 
 #include <asm-generic/pgtable-nopud.h>
 
+#ifdef CONFIG_HIGHMEM
+/* Clear a kernel PTE and flush it from the TLB */
+#define kpte_clear_flush(ptep, vaddr)					\
+do {									\
+	pte_clear(&init_mm, vaddr, ptep);				\
+	__flush_tlb_one(vaddr);						\
+} while (0)
+#endif
+
 #endif
 #endif