[PATCH v5 2/8] ACPI: add config for BIOS table scan

[Shannon Zhao <zhaoshenglong@huawei.com>]

From: Graeme Gregory <graeme.gregory@linaro.org>

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>
[Linux commit 8a1664be0b922dd6afd60eca96a992ef5ec22c40]
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
---
Cc: Jan Beulich <jbeulich@suse.com>
---
 xen/arch/x86/Kconfig     | 1 +
 xen/drivers/acpi/Kconfig | 3 +++
 xen/drivers/acpi/osl.c   | 4 +++-
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index 7d2ed96..3a25288 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -5,6 +5,7 @@ config X86
 	def_bool y
 	select COMPAT
 	select HAS_ACPI
+	select ACPI_LEGACY_TABLES_LOOKUP if HAS_ACPI
 	select HAS_CPUFREQ
 	select HAS_EHCI
 	select HAS_GDBSX
diff --git a/xen/drivers/acpi/Kconfig b/xen/drivers/acpi/Kconfig
index 11ab5e4..82d73ca 100644
--- a/xen/drivers/acpi/Kconfig
+++ b/xen/drivers/acpi/Kconfig
@@ -2,3 +2,6 @@
 # Select HAS_ACPI if ACPI is supported
 config HAS_ACPI
 	bool
+
+config ACPI_LEGACY_TABLES_LOOKUP
+	bool
diff --git a/xen/drivers/acpi/osl.c b/xen/drivers/acpi/osl.c
index ce15470..a2fc8c4 100644
--- a/xen/drivers/acpi/osl.c
+++ b/xen/drivers/acpi/osl.c
@@ -75,12 +75,14 @@ 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;
 }
 
 void __iomem *
-- 
2.0.4