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authorJisheng Zhang <jszhang@marvell.com>2015-11-25 23:42:49 +0800
committerDaniel Lezcano <daniel.lezcano@linaro.org>2015-12-16 09:45:10 +0100
commit272a25a247ce6d31315856721014635469500e96 (patch)
tree8048afdbd8078cd6b5075584656ae66040d638e5 /drivers/clocksource
parent08e4b44852626f3549c8bd45308431d9c9e0ee6d (diff)
downloadlinux-272a25a247ce6d31315856721014635469500e96.tar.bz2
clocksource/drivers/pistachio: Fix wrong calculated clocksource read value
Let's assume the counter value is 0xf0000000, the pistachio clocksource read cycles function should return ~0x0fffffff but actually it returns 0xffffffff0fffffff. That occurs because: ~(cycle_t)value is different from (cycle_t)~value. unsigned long val = ~(unsigned long)0xf0000000; 40049a: 48 b8 ff ff ff 0f ff movabs $0xffffffff0fffffff,%rax unsigned long val = (unsigned long)~0xf0000000; 40049a: 48 c7 45 f8 ff ff ff movq $0xfffffff,-0x8(%rbp) We fix this issue by calculating bitwise-not counter, then cast to cycle_t. Signed-off-by: Jisheng Zhang <jszhang@marvell.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Diffstat (limited to 'drivers/clocksource')
-rw-r--r--drivers/clocksource/time-pistachio.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/clocksource/time-pistachio.c b/drivers/clocksource/time-pistachio.c
index bba679900054..3269d9ef7a18 100644
--- a/drivers/clocksource/time-pistachio.c
+++ b/drivers/clocksource/time-pistachio.c
@@ -84,7 +84,7 @@ pistachio_clocksource_read_cycles(struct clocksource *cs)
counter = gpt_readl(pcs->base, TIMER_CURRENT_VALUE, 0);
raw_spin_unlock_irqrestore(&pcs->lock, flags);
- return ~(cycle_t)counter;
+ return (cycle_t)~counter;
}
static u64 notrace pistachio_read_sched_clock(void)