From: Andrew Morton <akpm@osdl.org>
Dopey div-by-zero workaround for HPET fallback.
http://lkml.org/lkml/2005/6/8/34
Cc: Robert Picco <Robert.Picco@hp.com>
Cc: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
arch/x86_64/kernel/time.c | 13 +++++++++----
1 files changed, 9 insertions(+), 4 deletions(-)
diff -puN arch/x86_64/kernel/time.c~x86_64-div-by-zero-fix arch/x86_64/kernel/time.c
--- devel/arch/x86_64/kernel/time.c~x86_64-div-by-zero-fix 2005-09-07 20:10:36.000000000 -0700
+++ devel-akpm/arch/x86_64/kernel/time.c 2005-09-07 20:10:36.000000000 -0700
@@ -76,6 +76,11 @@ unsigned long __wall_jiffies __section_w
struct timespec __xtime __section_xtime;
struct timezone __sys_tz __section_sys_tz;
+static inline unsigned long fixed_hpet_tick(void)
+{
+ return hpet_tick ? hpet_tick : 1;
+}
+
static inline void rdtscll_sync(unsigned long *tsc)
{
#ifdef CONFIG_SMP
@@ -305,7 +310,7 @@ unsigned long long monotonic_clock(void)
} while (read_seqretry(&xtime_lock, seq));
offset = (this_offset - last_offset);
- offset *=(NSEC_PER_SEC/HZ)/hpet_tick;
+ offset *=(NSEC_PER_SEC/HZ)/fixed_hpet_tick();
return base + offset;
}else{
do {
@@ -400,11 +405,11 @@ static irqreturn_t timer_interrupt(int i
if (vxtime.mode == VXTIME_HPET) {
if (offset - vxtime.last > hpet_tick) {
- lost = (offset - vxtime.last) / hpet_tick - 1;
+ lost = (offset - vxtime.last) / fixed_hpet_tick() - 1;
}
- monotonic_base +=
- (offset - vxtime.last)*(NSEC_PER_SEC/HZ) / hpet_tick;
+ monotonic_base += (offset - vxtime.last)*(NSEC_PER_SEC/HZ) /
+ fixed_hpet_tick();
vxtime.last = offset;
#ifdef CONFIG_X86_PM_TIMER
_