genirq: GENERIC_IRQ_EFFECTIVE_AFF_MASK depends on SMP

An IRQ's effective affinity can only be different from its configured
affinity if there are multiple CPUs. Make it clear that this option is
only meaningful when SMP is enabled. Most of the relevant code in
irqdesc.c is already hidden behind CONFIG_SMP anyway.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220701200056.46555-4-samuel@sholland.org

Author: smaeul

arch/arm/mach-hisi/Kconfig

@@ -40,7 +40,7 @@ config ARCH_HIP04
 	select HAVE_ARM_ARCH_TIMER
 	select MCPM if SMP
 	select MCPM_QUAD_CLUSTER if SMP
-	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
 	help
 	  Support for Hisilicon HiP04 SoC family
 

drivers/irqchip/Kconfig

@@ -8,7 +8,7 @@ config IRQCHIP
 config ARM_GIC
 	bool
 	select IRQ_DOMAIN_HIERARCHY
-	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
 
 config ARM_GIC_PM
 	bool
@@ -34,7 +34,7 @@ config ARM_GIC_V3
 	bool
 	select IRQ_DOMAIN_HIERARCHY
 	select PARTITION_PERCPU
-	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
 
 config ARM_GIC_V3_ITS
 	bool
@@ -76,7 +76,7 @@ config ARMADA_370_XP_IRQ
 	bool
 	select GENERIC_IRQ_CHIP
 	select PCI_MSI if PCI
-	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
 
 config ALPINE_MSI
 	bool
@@ -112,15 +112,15 @@ config BCM6345_L1_IRQ
 	bool
 	select GENERIC_IRQ_CHIP
 	select IRQ_DOMAIN
-	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
 
 config BCM7038_L1_IRQ
 	tristate "Broadcom STB 7038-style L1/L2 interrupt controller driver"
 	depends on ARCH_BRCMSTB || BMIPS_GENERIC
 	default ARCH_BRCMSTB || BMIPS_GENERIC
 	select GENERIC_IRQ_CHIP
 	select IRQ_DOMAIN
-	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
 
 config BCM7120_L2_IRQ
 	tristate "Broadcom STB 7120-style L2 interrupt controller driver"
@@ -179,7 +179,7 @@ config IRQ_MIPS_CPU
 	select GENERIC_IRQ_CHIP
 	select GENERIC_IRQ_IPI if SMP && SYS_SUPPORTS_MULTITHREADING
 	select IRQ_DOMAIN
-	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
 
 config CLPS711X_IRQCHIP
 	bool
@@ -294,7 +294,7 @@ config VERSATILE_FPGA_IRQ_NR
 config XTENSA_MX
 	bool
 	select IRQ_DOMAIN
-	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
 
 config XILINX_INTC
 	bool "Xilinx Interrupt Controller IP"

kernel/irq/Kconfig

@@ -24,6 +24,7 @@ config GENERIC_IRQ_SHOW_LEVEL
 
 # Supports effective affinity mask
 config GENERIC_IRQ_EFFECTIVE_AFF_MASK
+       depends on SMP
        bool
 
 # Support for delayed migration from interrupt context