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From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ben Horgan <ben.horgan@arm.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>
Subject: [PATCH 3/3] arm64: Convert __delay_cycles() to arch_timer_read_vcounter()
Date: Thu, 26 Feb 2026 08:22:34 +0000	[thread overview]
Message-ID: <20260226082234.26707-4-maz@kernel.org> (raw)
In-Reply-To: <20260226082234.26707-1-maz@kernel.org>

Relax the need for disabling preemption in __delay_cycles() by
using arch_timer_read_vcounter(), which will disable preemption
only when this is actually required.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/lib/delay.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/lib/delay.c b/arch/arm64/lib/delay.c
index e278e060e78a9..a667df920697d 100644
--- a/arch/arm64/lib/delay.c
+++ b/arch/arm64/lib/delay.c
@@ -32,10 +32,9 @@ static inline unsigned long xloops_to_cycles(unsigned long xloops)
  * Note that userspace cannot change the offset behind our back either,
  * as the vcpu mutex is held as long as KVM_RUN is in progress.
  */
-static cycles_t notrace __delay_cycles(void)
+static cycles_t __delay_cycles(void)
 {
-	guard(preempt_notrace)();
-	return __arch_counter_get_cntvct_stable();
+	return arch_timer_read_vcounter();
 }
 
 void __delay(unsigned long cycles)
-- 
2.47.3



  parent reply	other threads:[~2026-02-26  8:22 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-26  8:22 [PATCH 0/3] arm64: WFxT fixes, take #2 Marc Zyngier
2026-02-26  8:22 ` [PATCH 1/3] arm64: Fix sampling the "stable" virtual counter in preemptible section Marc Zyngier
2026-02-26  8:22 ` [PATCH 2/3] clocksource/drivers/arm_arch_timer: Expose a direct accessor for the virtual counter Marc Zyngier
2026-02-26 13:48   ` Ben Horgan
2026-02-26 14:03     ` Ben Horgan
2026-02-26 16:48       ` Marc Zyngier
2026-02-26 18:09         ` Will Deacon
2026-02-26  8:22 ` Marc Zyngier [this message]
2026-02-26 12:53 ` [PATCH 0/3] arm64: WFxT fixes, take #2 André Draszik
2026-02-26 13:36 ` Ben Horgan
2026-02-27  3:16 ` Will Deacon

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