acpi: Introduce acpi_arch_get_root_pointer() for getting rsdp address

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.

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/20180219100906.14265-2-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 3bb46cb24a9966ac86b950d53c817e523fe7cd40..7ca41bf023c9f354cad85617f0cceab228640d65 100644 (file)
--- 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 968173ec2726d64367d18d88558975833366bc5b..15bfb15c2fa5e1c369184c3839aa2131a416b0bd 100644 (file)
--- 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