From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Shier <pshier@google.com>,
Raghavendra Rao Ananta <rananta@google.com>,
Ricardo Koller <ricarkol@google.com>,
Oliver Upton <oupton@google.com>, Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Linus Walleij <linus.walleij@linaro.org>,
kernel-team@android.com
Subject: [PATCH v2 13/16] clocksource/arch_arm_timer: Move workaround synchronisation around
Date: Wed, 22 Sep 2021 22:19:38 +0100 [thread overview]
Message-ID: <20210922211941.2756270-14-maz@kernel.org> (raw)
In-Reply-To: <20210922211941.2756270-1-maz@kernel.org>
We currently handle synchronisation when workarounds are enabled
by having an ISB in the __arch_counter_get_cnt?ct_stable() helpers.
WHile this works, this prevents us from relaxing this synchronisation.
Instead, move it closer to the point where the synchronisation is
actually needed. Further patches will subsequently relax this.
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/arch_timer.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index b8000ef71a2c..519ac1f7f859 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h
@@ -32,7 +32,7 @@
({ \
const struct arch_timer_erratum_workaround *__wa; \
__wa = __this_cpu_read(timer_unstable_counter_workaround); \
- (__wa && __wa->h) ? __wa->h : arch_timer_##h; \
+ (__wa && __wa->h) ? ({ isb(); __wa->h;}) : arch_timer_##h; \
})
#else
@@ -64,11 +64,13 @@ DECLARE_PER_CPU(const struct arch_timer_erratum_workaround *,
static inline notrace u64 arch_timer_read_cntpct_el0(void)
{
+ isb();
return read_sysreg(cntpct_el0);
}
static inline notrace u64 arch_timer_read_cntvct_el0(void)
{
+ isb();
return read_sysreg(cntvct_el0);
}
@@ -163,7 +165,6 @@ static __always_inline u64 __arch_counter_get_cntpct_stable(void)
{
u64 cnt;
- isb();
cnt = arch_timer_reg_read_stable(cntpct_el0);
arch_counter_enforce_ordering(cnt);
return cnt;
@@ -183,7 +184,6 @@ static __always_inline u64 __arch_counter_get_cntvct_stable(void)
{
u64 cnt;
- isb();
cnt = arch_timer_reg_read_stable(cntvct_el0);
arch_counter_enforce_ordering(cnt);
return cnt;
--
2.30.2
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next prev parent reply other threads:[~2021-09-22 21:30 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-22 21:19 [PATCH v2 00/16] clocksource/arm_arch_timer: Add basic ARMv8.6 support Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 01/16] clocksource/arm_arch_timer: Add build-time guards for unhandled register accesses Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 02/16] clocksource/arm_arch_timer: Drop CNT*_TVAL read accessors Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 03/16] clocksource/arm_arch_timer: Extend write side of timer register accessors to u64 Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 04/16] clocksource/arm_arch_timer: Move system register timer programming over to CVAL Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 05/16] clocksource/arm_arch_timer: Move drop _tval from erratum function names Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 06/16] clocksource/arm_arch_timer: Fix MMIO base address vs callback ordering issue Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 07/16] clocksource/arm_arch_timer: Move MMIO timer programming over to CVAL Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 08/16] clocksource/arm_arch_timer: Advertise 56bit timer to the core code Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 09/16] clocksource/arm_arch_timer: Work around broken CVAL implementations Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 10/16] clocksource/arm_arch_timer: Remove any trace of the TVAL programming interface Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 11/16] clocksource/arm_arch_timer: Drop unnecessary ISB on CVAL programming Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 12/16] clocksource/arm_arch_timer: Fix masking for high freq counters Marc Zyngier
2021-09-22 21:19 ` Marc Zyngier [this message]
2021-09-22 21:19 ` [PATCH v2 14/16] arm64: Add a capability for FEAT_ECV Marc Zyngier
2021-09-29 16:03 ` Will Deacon
2021-09-30 7:42 ` Marc Zyngier
2021-09-30 8:30 ` Will Deacon
2021-09-22 21:19 ` [PATCH v2 15/16] arm64: Add CNT{P, V}CTSS_EL0 alternatives to cnt{p, v}ct_el0 Marc Zyngier
2021-09-22 21:19 ` [PATCH v2 16/16] arm64: Add handling of CNTVCTSS traps Marc Zyngier
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