x86/acpi: Add a new x86_init_acpi structure to x86_init_ops

Add a new struct x86_init_acpi to x86_init_ops. For now it contains
only one init function to get the RSDP table address.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: boris.ostrovsky@oracle.com
Cc: lenb@kernel.org
Cc: linux-acpi@vger.kernel.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20180219100906.14265-3-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/acpi.h

@@ -31,6 +31,7 @@
 #include <asm/mmu.h>
 #include <asm/mpspec.h>
 #include <asm/realmode.h>
+#include <asm/x86_init.h>
 
 #ifdef CONFIG_ACPI_APEI
 # include <asm/pgtable_types.h>
@@ -133,6 +134,12 @@ static inline bool acpi_has_cpu_in_madt(void)
 	return !!acpi_lapic;
 }
 
+#define ACPI_HAVE_ARCH_GET_ROOT_POINTER
+static inline u64 acpi_arch_get_root_pointer(void)
+{
+	return x86_init.acpi.get_root_pointer();
+}
+
 #else /* !CONFIG_ACPI */
 
 #define acpi_lapic 0

arch/x86/include/asm/x86_init.h

@@ -130,6 +130,14 @@ struct x86_hyper_init {
 	void (*init_mem_mapping)(void);
 };
 
+/**
+ * struct x86_init_acpi - x86 ACPI init functions
+ * @get_root_pointer:		get RSDP address
+ */
+struct x86_init_acpi {
+	u64 (*get_root_pointer)(void);
+};
+
 /**
  * struct x86_init_ops - functions for platform specific setup
  *
@@ -144,6 +152,7 @@ struct x86_init_ops {
 	struct x86_init_iommu		iommu;
 	struct x86_init_pci		pci;
 	struct x86_hyper_init		hyper;
+	struct x86_init_acpi		acpi;
 };
 
 /**

arch/x86/kernel/x86_init.c

@@ -30,6 +30,7 @@ int __init iommu_init_noop(void) { return 0; }
 void iommu_shutdown_noop(void) { }
 bool __init bool_x86_init_noop(void) { return false; }
 void x86_op_int_noop(int cpu) { }
+u64 u64_x86_init_noop(void) { return 0; }
 
 /*
  * The platform setup functions are preset with the default functions
@@ -91,6 +92,10 @@ struct x86_init_ops x86_init __initdata = {
 		.x2apic_available	= bool_x86_init_noop,
 		.init_mem_mapping	= x86_init_noop,
 	},
+
+	.acpi = {
+		.get_root_pointer	= u64_x86_init_noop,
+	},
 };
 
 struct x86_cpuinit_ops x86_cpuinit = {