diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 5424a18f2e4efbb3d21608d1cc38f64e7f328792..7217834f6b1dbc37d0f725059086cad01f612c80 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -124,12 +124,14 @@ char *__init __acpi_map_table(unsigned long phys, unsigned long size)
 	static char *prev_map;
 	static unsigned long prev_size;
 
+	if (prev_map) {
+		early_iounmap(prev_map, prev_size);
+		prev_map = NULL;
+	}
+
 	if (!phys || !size)
 		return NULL;
 
-	if (prev_map)
-		early_iounmap(prev_map, prev_size);
-
 	prev_size = size;
 	prev_map = early_ioremap(phys, size);
 
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 765fd1c56cd66bc445ab5228f562177b9eb469e1..fb1be7b5dbc1077f3bbc206803a467dbb36bb5ea 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -694,6 +694,12 @@ void __init acpi_early_init(void)
 	if (!acpi_strict)
 		acpi_gbl_enable_interpreter_slack = TRUE;
 
+	/*
+	 * Doing a zero-sized mapping will clear out the previous
+	 * __acpi_map_table() mapping, if any.
+	 */
+	__acpi_map_table(0, 0);
+
 	acpi_gbl_permanent_mmap = 1;
 
 	status = acpi_reallocate_root_table();