irqchip: gic-v3: Initial support for GICv3

The Generic Interrupt Controller (version 3) offers services that are
similar to GICv2, with a number of additional features:
- Affinity routing based on the CPU MPIDR (ARE)
- System register for the CPU interfaces (SRE)
- Support for more that 8 CPUs
- Locality-specific Peripheral Interrupts (LPIs)
- Interrupt Translation Services (ITS)

This patch adds preliminary support for GICv3 with ARE and SRE,
non-secure mode only. It relies on higher exception levels to grant ARE
and SRE access.

Support for LPI and ITS will be added at a later time.

Cc: Thomas Gleixner <[email protected]>
Cc: Jason Cooper <[email protected]>
Reviewed-by: Zi Shen Lim <[email protected]>
Reviewed-by: Christoffer Dall <[email protected]>
Reviewed-by: Tirumalesh Chalamarla <[email protected]>
Reviewed-by: Yun Wu <[email protected]>
Reviewed-by: Zhen Lei <[email protected]>
Tested-by: Tirumalesh Chalamarla<[email protected]>
Tested-by: Radha Mohan Chintakuntla <[email protected]>
Acked-by: Radha Mohan Chintakuntla <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Reviewed-by: Mark Rutland <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Jason Cooper <[email protected]>

arch/arm64/Kconfig

@@ -9,6 +9,7 @@ config ARM64
 	select ARM_AMBA
 	select ARM_ARCH_TIMER
 	select ARM_GIC
+	select ARM_GIC_V3
 	select BUILDTIME_EXTABLE_SORT
 	select CLONE_BACKWARDS
 	select COMMON_CLK

arch/arm64/kernel/head.S

@@ -22,6 +22,7 @@
 
 #include <linux/linkage.h>
 #include <linux/init.h>
+#include <linux/irqchip/arm-gic-v3.h>
 
 #include <asm/assembler.h>
 #include <asm/ptrace.h>
@@ -296,6 +297,23 @@ CPU_LE(	bic	x0, x0, #(3 << 24)	)	// Clear the EE and E0E bits for EL1
 	msr	cnthctl_el2, x0
 	msr	cntvoff_el2, xzr		// Clear virtual offset
 
+#ifdef CONFIG_ARM_GIC_V3
+	/* GICv3 system register access */
+	mrs	x0, id_aa64pfr0_el1
+	ubfx	x0, x0, #24, #4
+	cmp	x0, #1
+	b.ne	3f
+
+	mrs	x0, ICC_SRE_EL2
+	orr	x0, x0, #ICC_SRE_EL2_SRE	// Set ICC_SRE_EL2.SRE==1
+	orr	x0, x0, #ICC_SRE_EL2_ENABLE	// Set ICC_SRE_EL2.Enable==1
+	msr	ICC_SRE_EL2, x0
+	isb					// Make sure SRE is now set
+	msr	ICH_HCR_EL2, xzr		// Reset ICC_HCR_EL2 to defaults
+
+3:
+#endif
+
 	/* Populate ID registers. */
 	mrs	x0, midr_el1
 	mrs	x1, mpidr_el1

arch/arm64/kernel/hyp-stub.S

@@ -19,6 +19,7 @@
 
 #include <linux/init.h>
 #include <linux/linkage.h>
+#include <linux/irqchip/arm-gic-v3.h>
 
 #include <asm/assembler.h>
 #include <asm/ptrace.h>

drivers/irqchip/Kconfig

@@ -10,6 +10,11 @@ config ARM_GIC
 config GIC_NON_BANKED
 	bool
 
+config ARM_GIC_V3
+	bool
+	select IRQ_DOMAIN
+	select MULTI_IRQ_HANDLER
+
 config ARM_NVIC
 	bool
 	select IRQ_DOMAIN

drivers/irqchip/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_ARCH_SUNXI)		+= irq-sun4i.o
 obj-$(CONFIG_ARCH_SUNXI)		+= irq-sunxi-nmi.o
 obj-$(CONFIG_ARCH_SPEAR3XX)		+= spear-shirq.o
 obj-$(CONFIG_ARM_GIC)			+= irq-gic.o irq-gic-common.o
+obj-$(CONFIG_ARM_GIC_V3)		+= irq-gic-v3.o irq-gic-common.o
 obj-$(CONFIG_ARM_NVIC)			+= irq-nvic.o
 obj-$(CONFIG_ARM_VIC)			+= irq-vic.o
 obj-$(CONFIG_IMGPDC_IRQ)		+= irq-imgpdc.o