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| author | Jisheng Zhang <jszhang@marvell.com> | 2015-11-25 23:42:49 +0800 |
|---|---|---|
| committer | Daniel Lezcano <daniel.lezcano@linaro.org> | 2015-12-16 09:45:10 +0100 |
| commit | 272a25a247ce6d31315856721014635469500e96 (patch) | |
| tree | 8048afdbd8078cd6b5075584656ae66040d638e5 /drivers/clocksource | |
| parent | 08e4b44852626f3549c8bd45308431d9c9e0ee6d (diff) | |
| download | linux-0-day-272a25a247ce6d31315856721014635469500e96.tar.gz linux-0-day-272a25a247ce6d31315856721014635469500e96.tar.xz | |
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.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/clocksource/time-pistachio.c b/drivers/clocksource/time-pistachio.c index bba6799000541..3269d9ef7a18a 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) |