From: Valentin Schneider <valentin.schneider@arm.com>
To: Marc Zyngier <marc.zyngier@arm.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Cc: Russell King <linux@arm.linux.org.uk>,
Will Deacon <will.deacon@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Wim Van Sebroeck <wim@linux-watchdog.org>,
Guenter Roeck <linux@roeck-us.net>
Subject: Re: [PATCH 7/7] clocksource/arm_arch_timer: Use arch_timer_read_counter to access stable counters
Date: Tue, 30 Apr 2019 16:39:24 +0100 [thread overview]
Message-ID: <cef220b8-f46d-0653-8249-a9d48b2efc48@arm.com> (raw)
In-Reply-To: <bbe9b8c1-132f-bbfa-e3d0-ad10c4165ad7@arm.com>
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.
[...]
next prev parent reply other threads:[~2019-04-30 15:39 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-08 15:49 [PATCH 0/7] clocksource/arm_arch_timer: Removing the static branch on errata handling Marc Zyngier
2019-04-08 15:49 ` [PATCH 1/7] ARM: vdso: Remove dependency with the arch_timer driver internals Marc Zyngier
2019-04-08 15:58 ` Mark Rutland
2019-04-15 10:46 ` Marc Zyngier
2019-04-30 14:23 ` Will Deacon
2019-04-08 15:49 ` [PATCH 2/7] watchdog/sbsa: Use arch_timer_read_counter instead of arch_counter_get_cntvct Marc Zyngier
2019-04-08 15:59 ` Mark Rutland
2019-04-08 18:07 ` Guenter Roeck
2019-04-09 7:43 ` Marc Zyngier
2019-04-08 15:49 ` [PATCH 3/7] arm64: " Marc Zyngier
2019-04-08 15:59 ` Mark Rutland
2019-04-08 15:49 ` [PATCH 4/7] clocksource/arm_arch_timer: Direcly assign set_next_event workaround Marc Zyngier
2019-04-08 16:02 ` Mark Rutland
2019-04-11 17:17 ` Daniel Lezcano
2019-04-15 10:18 ` Marc Zyngier
2019-04-08 15:49 ` [PATCH 5/7] clocksource/arm_arch_timer: Drop use of static key in arch_timer_reg_read_stable Marc Zyngier
2019-04-08 16:04 ` Mark Rutland
2019-04-15 11:04 ` Daniel Lezcano
2019-04-08 15:49 ` [PATCH 6/7] clocksource/arm_arch_timer: Remove use of workaround static key Marc Zyngier
2019-04-08 16:05 ` Mark Rutland
2019-04-15 11:07 ` Daniel Lezcano
2019-04-08 15:49 ` [PATCH 7/7] clocksource/arm_arch_timer: Use arch_timer_read_counter to access stable counters Marc Zyngier
2019-04-08 16:08 ` Mark Rutland
2019-04-15 12:16 ` Daniel Lezcano
2019-04-30 15:27 ` Marc Zyngier
2019-04-30 15:39 ` Valentin Schneider [this message]
2019-05-03 20:32 ` Daniel Lezcano
2019-05-03 20:31 ` Daniel Lezcano
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