From 2e62352bc28bd5d3efafc1b5cbe211ff9e9987fd Mon Sep 17 00:00:00 2001
From: Vladimir Serbinenko <phcoder@gmail.com>
Date: Tue, 20 Jan 2015 21:07:08 +0100
Subject: [PATCH 162/506] 	* grub-core/kern/i386/tsc.c (calibrate_tsc):
 Ensure that 	no division by 0 occurs.

---
 ChangeLog                 | 5 +++++
 grub-core/kern/i386/tsc.c | 6 +++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index ecbe11d..c2551db 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2015-01-20  Vladimir Serbinenko  <phcoder@gmail.com>
 
+	* grub-core/kern/i386/tsc.c (calibrate_tsc): Ensure that
+	no division by 0 occurs.
+
+2015-01-20  Vladimir Serbinenko  <phcoder@gmail.com>
+
 	* include/grub/misc.h (grub_div_roundup): Remove as it's unused.
 
 2015-01-20  Vladimir Serbinenko  <phcoder@gmail.com>
diff --git a/grub-core/kern/i386/tsc.c b/grub-core/kern/i386/tsc.c
index 3a4cae6..d7d1783 100644
--- a/grub-core/kern/i386/tsc.c
+++ b/grub-core/kern/i386/tsc.c
@@ -122,7 +122,11 @@ calibrate_tsc (void)
   grub_pit_wait (0xffff);
   end_tsc = grub_get_tsc ();
 
-  grub_tsc_rate = grub_divmod64 ((55ULL << 32), end_tsc - tsc_boot_time, 0);
+  grub_tsc_rate = 0;
+  if (end_tsc > tsc_boot_time)
+    grub_tsc_rate = grub_divmod64 ((55ULL << 32), end_tsc - tsc_boot_time, 0);
+  if (grub_tsc_rate == 0)
+    grub_tsc_rate = 5368;/* 800 MHz */
 }
 #endif
 
-- 
2.4.3