[PATCH v2 4/6] arm: Mark the recheduling IPI as raw interrupt

Marc Zyngier
2020-11-24T14:15:40Z

Flag the rescheduling IPI as 'raw', making sure such interrupt
skips both tick management and irqtime accounting.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm/Kconfig | 1 +
arch/arm/kernel/smp.c | 4 ++++
2 files changed, 5 insertions(+)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index fe2f17eb2b50..a5e3e9963ba4 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -50,6 +50,7 @@ config ARM
select GENERIC_ATOMIC64 if CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI
select GENERIC_CLOCKEVENTS_BROADCAST if SMP
select GENERIC_IRQ_IPI if SMP
+ select ARCH_WANTS_IRQ_RAW if GENERIC_IRQ_IPI
select GENERIC_CPU_AUTOPROBE
select GENERIC_EARLY_IOREMAP
select GENERIC_IDLE_POLL_SETUP
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 48099c6e1e4a..0e09c8320caf 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -738,6 +738,10 @@ void __init set_smp_ipi_range(int ipi_base, int n)

ipi_desc[i] = irq_to_desc(ipi_base + i);
irq_set_status_flags(ipi_base + i, IRQ_HIDDEN);
+
+ /* The recheduling IPI is special... */
+ if (i == IPI_RESCHEDULE)
+ __irq_modify_status(ipi_base + i, 0, IRQ_RAW, ~0);
}

ipi_irq_base = ipi_base;
--
2.28.0