x86/hpet: Use the FSEC_PER_SEC constant for femto-second periods

The current computation, introduced with f12a15be63, of FSEC_PER_SEC using
the multiplication of (FSEC_PER_NSEC * NSEC_PER_SEC) is performed only
with 32bit integers on small machines, resulting in an overflow and a
*very* short intervals being programmed.  An interrupt storm follows.

Note that we also have to specify FSEC_PER_SEC as being long long to
overcome the same limitations.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/linux/time.h b/include/linux/time.h
index cb34e35fabac..12612701b1ae 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -38,7 +38,7 @@ extern struct timezone sys_tz;
 #define NSEC_PER_MSEC   1000000L
 #define USEC_PER_SEC    1000000L
 #define NSEC_PER_SEC    1000000000L
-#define FSEC_PER_SEC    1000000000000000L
+#define FSEC_PER_SEC    1000000000000000LL
 
 #define TIME_T_MAX      (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)