From: Vladimir Serbinenko <phcoder@gmail.com>
Date: Tue, 20 Jan 2015 20:07:08 +0000 (+0100)
Subject: 	* grub-core/kern/i386/tsc.c (calibrate_tsc): Ensure that
X-Git-Tag: 2.02-beta3~560
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2e62352bc28bd5d3efafc1b5cbe211ff9e9987fd;p=thirdparty%2Fgrub.git

	* grub-core/kern/i386/tsc.c (calibrate_tsc): Ensure that
	no division by 0 occurs.
---

diff --git a/ChangeLog b/ChangeLog
index ecbe11dc5..c2551db30 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+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.
diff --git a/grub-core/kern/i386/tsc.c b/grub-core/kern/i386/tsc.c
index 3a4cae601..d7d1783e4 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