acpi/x86: introduce __apci_map_table, v4

to prevent wrongly overwriting fixmap that still want to use.

ACPI used to rely on low mappings being all linearly mapped and
grew a habit: it never really unmapped certain kinds of tables
after use.

This can cause problems - for example the hypothetical case
when some spurious access still references it.

v2: remove prev_map and prev_size in __apci_map_table
v3: let acpi_os_unmap_memory() call early_iounmap too, so remove extral calling to
early_acpi_os_unmap_memory
v4: fix typo in one acpi_get_table_with_size calling

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Acked-by: Len Brown <len.brown@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 6fce2fc..d59f0fa 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -79,6 +79,7 @@
 typedef int (*acpi_table_entry_handler) (struct acpi_subtable_header *header, const unsigned long end);
 
 char * __acpi_map_table (unsigned long phys_addr, unsigned long size);
+void __init __acpi_unmap_table(char *map, unsigned long size);
 int early_acpi_boot_init(void);
 int acpi_boot_init (void);
 int acpi_boot_table_init (void);