diff --git a/include/asm-x86/io.h b/include/asm-x86/io.h
index c63563df4ac8089616f755e895c63b51901ed693..bf5d629b3a39a369256564db15ba2d66eb4a014a 100644
--- a/include/asm-x86/io.h
+++ b/include/asm-x86/io.h
@@ -5,6 +5,20 @@
 
 #include <linux/compiler.h>
 
+/*
+ * early_ioremap() and early_iounmap() are for temporary early boot-time
+ * mappings, before the real ioremap() is functional.
+ * A boot-time mapping is currently limited to at most 16 pages.
+ */
+#ifndef __ASSEMBLY__
+extern void early_ioremap_init(void);
+extern void early_ioremap_clear(void);
+extern void early_ioremap_reset(void);
+extern void *early_ioremap(unsigned long offset, unsigned long size);
+extern void early_iounmap(void *addr, unsigned long size);
+extern void __iomem *fix_ioremap(unsigned idx, unsigned long phys);
+#endif
+
 #define build_mmio_read(name, size, type, reg, barrier) \
 static inline type name(const volatile void __iomem *addr) \
 { type ret; asm volatile("mov" size " %1,%0":"=" reg (ret) \