ACPI: add config for BIOS table scan

With the addition of ARM64 that does not have a traditional BIOS to
scan, add a config option which is selected on x86 (ia64 doesn't need
it either, it is EFI/UEFI based system) to do the traditional BIOS
scanning for tables.

Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

3 files changed, 7 insertions, 1 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index d24887b645dc..5617750262db 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -132,6 +132,7 @@ config X86
         select GENERIC_CPU_AUTOPROBE
         select HAVE_ARCH_AUDITSYSCALL
         select ARCH_SUPPORTS_ATOMIC_RMW
+        select ACPI_LEGACY_TABLES_LOOKUP if ACPI
 
 config INSTRUCTION_DECODER
         def_bool y
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index a34a22841002..970524c54bfa 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -42,6 +42,9 @@ menuconfig ACPI
 
 if ACPI
 
+config ACPI_LEGACY_TABLES_LOOKUP
+        bool
+
 config ACPI_SLEEP
         bool
         depends on SUSPEND || HIBERNATION
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index bad25b070fe0..3abe9b223ba7 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -259,12 +259,14 @@ acpi_physical_address __init acpi_os_get_root_pointer(void)
                                "System description tables not found\n");
                         return 0;
                 }
-        } else {
+        } else if (IS_ENABLED(CONFIG_ACPI_LEGACY_TABLES_LOOKUP)) {
                 acpi_physical_address pa = 0;
 
                 acpi_find_root_pointer(&pa);
                 return pa;
         }
+
+        return 0;
 }
 
 /* Must be called with 'acpi_ioremap_lock' or RCU read lock held. */