Messages in this thread | | | Subject | Re: [PATCH 7/7] clocksource/arm_arch_timer: Use arch_timer_read_counter to access stable counters | From | Valentin Schneider <> | Date | Tue, 30 Apr 2019 16:39:24 +0100 |
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Hi,
On 30/04/2019 16:27, Marc Zyngier wrote: [...] >>> @@ -372,6 +392,7 @@ static u32 notrace sun50i_a64_read_cntv_tval_el0(void) >>> DEFINE_PER_CPU(const struct arch_timer_erratum_workaround *, timer_unstable_counter_workaround); >>> EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround); >>> >>> +static atomic_t timer_unstable_counter_workaround_in_use = ATOMIC_INIT(0); >> >> Wouldn't make sense to READ_ONCE / WRITE_ONCE instead of using an atomic? > > I don't think *_ONCE says anything about the atomicity of the access. It > only instruct the compiler that this should only be accessed once, and > not reloaded/rewritten.
FWIW 7bd3e239d6c6 ("locking: Remove atomicy checks from {READ,WRITE}_ONCE") points this out.
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