From: Jan Beulich <jbeulich@suse.com>
Date: Fri, 22 Feb 2013 10:51:06 +0000 (+0100)
Subject: x86: honor ACPI indicating absence of CMOS RTC
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~7228
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=f74556693bca2ff61e3e0c103f90e1d552d795b6;p=xen.git

x86: honor ACPI indicating absence of CMOS RTC

On such systems we can boot through EFI only.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
---

diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index 244b43e7f0..56bffdbe39 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -754,6 +754,9 @@ static unsigned long get_cmos_time(void)
             return res;
     }
 
+    if ( unlikely(acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) )
+        panic("System without CMOS RTC must be booted from EFI\n");
+
     spin_lock_irqsave(&rtc_lock, flags);
 
     /* read RTC exactly on falling edge of update flag */