SPARC64: Fix serious bug in sched_clock() on sparc64

Unfortunately, sparc64 doesn't have an easy way to do a "64 X 64 -->
128" bit multiply like PowerPC and IA64 do.  We were doing a
"64 X 64 --> 64" bit multiple which causes overflow very quickly with
a 30-bit quotient shift.

So use a quotientshift count of 10 instead of 30, just like x86 and
ARM do.

This also fixes the wrapping of printk timestamp values every ~17
seconds.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/sparc64/kernel/time.c b/arch/sparc64/kernel/time.c
index 094d3e35be18..b0b4feeec098 100644
--- a/arch/sparc64/kernel/time.c
+++ b/arch/sparc64/kernel/time.c
@@ -983,7 +983,7 @@ static struct time_interpolator sparc64_cpu_interpolator = {
 };
 
 /* The quotient formula is taken from the IA64 port. */
-#define SPARC64_NSEC_PER_CYC_SHIFT	30UL
+#define SPARC64_NSEC_PER_CYC_SHIFT	10UL
 void __init time_init(void)
 {
 	unsigned long clock = sparc64_init_timers();