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>

include/acpi/acpiosxf.h

@@ -144,6 +144,7 @@ void __iomem *acpi_os_map_memory(acpi_physical_address where,
 				acpi_size length);
 
 void acpi_os_unmap_memory(void __iomem * logical_address, acpi_size size);
+void early_acpi_os_unmap_memory(void __iomem * virt, acpi_size size);
 
 #ifdef ACPI_FUTURE_USAGE
 acpi_status

include/acpi/acpixf.h

@@ -130,6 +130,10 @@ acpi_get_table_header(acpi_string signature,
 		      struct acpi_table_header *out_table_header);
 
 acpi_status
+acpi_get_table_with_size(acpi_string signature,
+	       u32 instance, struct acpi_table_header **out_table,
+	       acpi_size *tbl_size);
+acpi_status
 acpi_get_table(acpi_string signature,
 	       u32 instance, struct acpi_table_header **out_table);