[PATCH v3 1/3] acpi: introduce acpi_arch_get_root_pointer() for getting rsdp address

[Juergen Gross]

Add an architecture specific function to get the address of the RSDP
table. Per default it will just return 0 indicating falling back to
the current mechanism.

Cc: <stable@xxxxxxxxxxxxxxx> # 4.11
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 drivers/acpi/osl.c   | 5 ++++-
 include/linux/acpi.h | 7 +++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 3bb46cb24a99..ff812243bac3 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -189,12 +189,15 @@ early_param("acpi_rsdp", setup_acpi_rsdp);
 
 acpi_physical_address __init acpi_os_get_root_pointer(void)
 {
-	acpi_physical_address pa = 0;
+	acpi_physical_address pa;
 
 #ifdef CONFIG_KEXEC
 	if (acpi_rsdp)
 		return acpi_rsdp;
 #endif
+	pa = acpi_arch_get_root_pointer();
+	if (pa)
+		return pa;
 
 	if (efi_enabled(EFI_CONFIG_TABLES)) {
 		if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 968173ec2726..15bfb15c2fa5 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -623,6 +623,13 @@ bool acpi_gtdt_c3stop(int type);
 int acpi_arch_timer_mem_init(struct arch_timer_mem *timer_mem, int *timer_count);
 #endif
 
+#ifndef ACPI_HAVE_ARCH_GET_ROOT_POINTER
+static inline u64 acpi_arch_get_root_pointer(void)
+{
+	return 0;
+}
+#endif
+
 #else	/* !CONFIG_ACPI */
 
 #define acpi_disabled 1
-- 
2.13.6