The CPU PMU in Apple SoCs can be configured to fire its interrupt in one
of several ways, and since Apple A11 one of the method is FIQ. Only handle
the PMC interrupt as a FIQ when the CPU PMU has been configured to fire
FIQs.

Cc: stable@vger.kernel.org
Fixes: c7708816c944 ("irqchip/apple-aic: Wire PMU interrupts")
Signed-off-by: Nick Chan <towinchenmi@gmail.com>
---

Changes in v2:
Fix the conditional to have the intented behavior of evaluating to true
only when both PMCR0_IMODE is PMCR0_IMODE_FIQ and PMCR0_IACT is set by
reverting the conditional to how it is before c7708816c944.

Link to v1: https://lore.kernel.org/asahi/20250117170227.45243-1-towinchenmi@gmail.com/T

- Nick Chan


 drivers/irqchip/irq-apple-aic.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-apple-aic.c b/drivers/irqchip/irq-apple-aic.c
index da5250f0155c..2b1684c60e3c 100644
--- a/drivers/irqchip/irq-apple-aic.c
+++ b/drivers/irqchip/irq-apple-aic.c
@@ -577,7 +577,8 @@ static void __exception_irq_entry aic_handle_fiq(struct pt_regs *regs)
 						  AIC_FIQ_HWIRQ(AIC_TMR_EL02_VIRT));
 	}
 
-	if (read_sysreg_s(SYS_IMP_APL_PMCR0_EL1) & PMCR0_IACT) {
+	if ((read_sysreg_s(SYS_IMP_APL_PMCR0_EL1) & (PMCR0_IMODE | PMCR0_IACT)) ==
+			(FIELD_PREP(PMCR0_IMODE, PMCR0_IMODE_FIQ) | PMCR0_IACT)) {
 		int irq;
 		if (cpumask_test_cpu(smp_processor_id(),
 				     &aic_irqc->fiq_aff[AIC_CPU_PMU_P]->aff))

base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37
-- 
2.48.1

The following commit has been merged into the irq/urgent branch of tip:

Commit-ID:     698244bbb3bfd32ddf9a0b70a12b1c7d69056497
Gitweb:        https://git.kernel.org/tip/698244bbb3bfd32ddf9a0b70a12b1c7d69056497
Author:        Nick Chan <towinchenmi@gmail.com>
AuthorDate:    Sun, 19 Jan 2025 00:31:42 +08:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Mon, 27 Jan 2025 18:39:15 +01:00

irqchip/apple-aic: Only handle PMC interrupt as FIQ when configured so

The CPU PMU in Apple SoCs can be configured to fire its interrupt in one of
several ways, and since Apple A11 one of the methods is FIQ, but the check
of the configuration register fails to test explicitely for FIQ mode. It
tests whether the IMODE bitfield is zero or not and the PMCRO_IACT bit is
set. That results in false positives when the IMODE bitfield is not zero,
but does not have the mode PMCR0_IMODE_FIQ.

Only handle the PMC interrupt as a FIQ when the CPU PMU has been configured
to fire FIQs, i.e. the IMODE bitfield value is PMCR0_IMODE_FIQ and
PMCR0_IACT is set.

Fixes: c7708816c944 ("irqchip/apple-aic: Wire PMU interrupts")
Signed-off-by: Nick Chan <towinchenmi@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250118163554.16733-1-towinchenmi@gmail.com
---
 drivers/irqchip/irq-apple-aic.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-apple-aic.c b/drivers/irqchip/irq-apple-aic.c
index da5250f..2b1684c 100644
--- a/drivers/irqchip/irq-apple-aic.c
+++ b/drivers/irqchip/irq-apple-aic.c
@@ -577,7 +577,8 @@ static void __exception_irq_entry aic_handle_fiq(struct pt_regs *regs)
 						  AIC_FIQ_HWIRQ(AIC_TMR_EL02_VIRT));
 	}
 
-	if (read_sysreg_s(SYS_IMP_APL_PMCR0_EL1) & PMCR0_IACT) {
+	if ((read_sysreg_s(SYS_IMP_APL_PMCR0_EL1) & (PMCR0_IMODE | PMCR0_IACT)) ==
+			(FIELD_PREP(PMCR0_IMODE, PMCR0_IMODE_FIQ) | PMCR0_IACT)) {
 		int irq;
 		if (cpumask_test_cpu(smp_processor_id(),
 				     &aic_irqc->fiq_aff[AIC_CPU_PMU_P]->aff))