Commit-ID: 272a25a247ce6d31315856721014635469500e96 Gitweb: http://git.kernel.org/tip/272a25a247ce6d31315856721014635469500e96 Author: Jisheng Zhang <jszhang@xxxxxxxxxxx> AuthorDate: Wed, 25 Nov 2015 23:42:49 +0800 Committer: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> CommitDate: Wed, 16 Dec 2015 09:45:10 +0100 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@xxxxxxxxxxx> Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> --- drivers/clocksource/time-pistachio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/clocksource/time-pistachio.c b/drivers/clocksource/time-pistachio.c index bba6799..3269d9e 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) -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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