Merge tag 'gic-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/core

GIC updates for Linux 4.4 from Marc Zyngier:

- Enable basic GICv3 support on 32bit ARM (mostly for running VMs with
  more than 8 virtual CPUs)
- arm64 changes to deal with firmware limitations that forces a GICv3
  to be used as a GICv2
- A GICv2m erratum workaround on Applied Micro X-Gene2

4 files changed, 194 insertions, 1 deletions

diff --git a/arch/arm64/include/asm/arch_gicv3.h b/arch/arm64/include/asm/arch_gicv3.h
new file mode 100644
index 000000000000..030cdcb46c6b
--- /dev/null
+++ b/arch/arm64/include/asm/arch_gicv3.h
@@ -0,0 +1,170 @@
+/*
+ * arch/arm64/include/asm/arch_gicv3.h
+ *
+ * Copyright (C) 2015 ARM Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __ASM_ARCH_GICV3_H
+#define __ASM_ARCH_GICV3_H
+
+#include <asm/sysreg.h>
+
+#define ICC_EOIR1_EL1			sys_reg(3, 0, 12, 12, 1)
+#define ICC_DIR_EL1			sys_reg(3, 0, 12, 11, 1)
+#define ICC_IAR1_EL1			sys_reg(3, 0, 12, 12, 0)
+#define ICC_SGI1R_EL1			sys_reg(3, 0, 12, 11, 5)
+#define ICC_PMR_EL1			sys_reg(3, 0, 4, 6, 0)
+#define ICC_CTLR_EL1			sys_reg(3, 0, 12, 12, 4)
+#define ICC_SRE_EL1			sys_reg(3, 0, 12, 12, 5)
+#define ICC_GRPEN1_EL1			sys_reg(3, 0, 12, 12, 7)
+
+#define ICC_SRE_EL2			sys_reg(3, 4, 12, 9, 5)
+
+/*
+ * System register definitions
+ */
+#define ICH_VSEIR_EL2			sys_reg(3, 4, 12, 9, 4)
+#define ICH_HCR_EL2			sys_reg(3, 4, 12, 11, 0)
+#define ICH_VTR_EL2			sys_reg(3, 4, 12, 11, 1)
+#define ICH_MISR_EL2			sys_reg(3, 4, 12, 11, 2)
+#define ICH_EISR_EL2			sys_reg(3, 4, 12, 11, 3)
+#define ICH_ELSR_EL2			sys_reg(3, 4, 12, 11, 5)
+#define ICH_VMCR_EL2			sys_reg(3, 4, 12, 11, 7)
+
+#define __LR0_EL2(x)			sys_reg(3, 4, 12, 12, x)
+#define __LR8_EL2(x)			sys_reg(3, 4, 12, 13, x)
+
+#define ICH_LR0_EL2			__LR0_EL2(0)
+#define ICH_LR1_EL2			__LR0_EL2(1)
+#define ICH_LR2_EL2			__LR0_EL2(2)
+#define ICH_LR3_EL2			__LR0_EL2(3)
+#define ICH_LR4_EL2			__LR0_EL2(4)
+#define ICH_LR5_EL2			__LR0_EL2(5)
+#define ICH_LR6_EL2			__LR0_EL2(6)
+#define ICH_LR7_EL2			__LR0_EL2(7)
+#define ICH_LR8_EL2			__LR8_EL2(0)
+#define ICH_LR9_EL2			__LR8_EL2(1)
+#define ICH_LR10_EL2			__LR8_EL2(2)
+#define ICH_LR11_EL2			__LR8_EL2(3)
+#define ICH_LR12_EL2			__LR8_EL2(4)
+#define ICH_LR13_EL2			__LR8_EL2(5)
+#define ICH_LR14_EL2			__LR8_EL2(6)
+#define ICH_LR15_EL2			__LR8_EL2(7)
+
+#define __AP0Rx_EL2(x)			sys_reg(3, 4, 12, 8, x)
+#define ICH_AP0R0_EL2			__AP0Rx_EL2(0)
+#define ICH_AP0R1_EL2			__AP0Rx_EL2(1)
+#define ICH_AP0R2_EL2			__AP0Rx_EL2(2)
+#define ICH_AP0R3_EL2			__AP0Rx_EL2(3)
+
+#define __AP1Rx_EL2(x)			sys_reg(3, 4, 12, 9, x)
+#define ICH_AP1R0_EL2			__AP1Rx_EL2(0)
+#define ICH_AP1R1_EL2			__AP1Rx_EL2(1)
+#define ICH_AP1R2_EL2			__AP1Rx_EL2(2)
+#define ICH_AP1R3_EL2			__AP1Rx_EL2(3)
+
+#ifndef __ASSEMBLY__
+
+#include <linux/stringify.h>
+
+/*
+ * Low-level accessors
+ *
+ * These system registers are 32 bits, but we make sure that the compiler
+ * sets the GP register's most significant bits to 0 with an explicit cast.
+ */
+
+static inline void gic_write_eoir(u32 irq)
+{
+	asm volatile("msr_s " __stringify(ICC_EOIR1_EL1) ", %0" : : "r" ((u64)irq));
+	isb();
+}
+
+static inline void gic_write_dir(u32 irq)
+{
+	asm volatile("msr_s " __stringify(ICC_DIR_EL1) ", %0" : : "r" ((u64)irq));
+	isb();
+}
+
+static inline u64 gic_read_iar_common(void)
+{
+	u64 irqstat;
+
+	asm volatile("mrs_s %0, " __stringify(ICC_IAR1_EL1) : "=r" (irqstat));
+	return irqstat;
+}
+
+/*
+ * Cavium ThunderX erratum 23154
+ *
+ * The gicv3 of ThunderX requires a modified version for reading the
+ * IAR status to ensure data synchronization (access to icc_iar1_el1
+ * is not sync'ed before and after).
+ */
+static inline u64 gic_read_iar_cavium_thunderx(void)
+{
+	u64 irqstat;
+
+	asm volatile(
+		"nop;nop;nop;nop\n\t"
+		"nop;nop;nop;nop\n\t"
+		"mrs_s %0, " __stringify(ICC_IAR1_EL1) "\n\t"
+		"nop;nop;nop;nop"
+		: "=r" (irqstat));
+	mb();
+
+	return irqstat;
+}
+
+static inline void gic_write_pmr(u32 val)
+{
+	asm volatile("msr_s " __stringify(ICC_PMR_EL1) ", %0" : : "r" ((u64)val));
+}
+
+static inline void gic_write_ctlr(u32 val)
+{
+	asm volatile("msr_s " __stringify(ICC_CTLR_EL1) ", %0" : : "r" ((u64)val));
+	isb();
+}
+
+static inline void gic_write_grpen1(u32 val)
+{
+	asm volatile("msr_s " __stringify(ICC_GRPEN1_EL1) ", %0" : : "r" ((u64)val));
+	isb();
+}
+
+static inline void gic_write_sgi1r(u64 val)
+{
+	asm volatile("msr_s " __stringify(ICC_SGI1R_EL1) ", %0" : : "r" (val));
+}
+
+static inline u32 gic_read_sre(void)
+{
+	u64 val;
+
+	asm volatile("mrs_s %0, " __stringify(ICC_SRE_EL1) : "=r" (val));
+	return val;
+}
+
+static inline void gic_write_sre(u32 val)
+{
+	asm volatile("msr_s " __stringify(ICC_SRE_EL1) ", %0" : : "r" ((u64)val));
+	isb();
+}
+
+#define gic_read_typer(c)		readq_relaxed(c)
+#define gic_write_irouter(v, c)		writeq_relaxed(v, c)
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_ARCH_GICV3_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 3c9aed32f70b..305f30dc9e63 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -23,6 +23,8 @@
 #include <asm/cpufeature.h>
 #include <asm/processor.h>
 
+#include <linux/irqchip/arm-gic-v3.h>
+
 static bool
 feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry)
 {
@@ -45,11 +47,26 @@ __ID_FEAT_CHK(id_aa64pfr0);
 __ID_FEAT_CHK(id_aa64mmfr1);
 __ID_FEAT_CHK(id_aa64isar0);
 
+static bool has_useable_gicv3_cpuif(const struct arm64_cpu_capabilities *entry)
+{
+	bool has_sre;
+
+	if (!has_id_aa64pfr0_feature(entry))
+		return false;
+
+	has_sre = gic_enable_sre();
+	if (!has_sre)
+		pr_warn_once("%s present but disabled by higher exception level\n",
+			     entry->desc);
+
+	return has_sre;
+}
+
 static const struct arm64_cpu_capabilities arm64_features[] = {
 	{
 		.desc = "GIC system register CPU interface",
 		.capability = ARM64_HAS_SYSREG_GIC_CPUIF,
-		.matches = has_id_aa64pfr0_feature,
+		.matches = has_useable_gicv3_cpuif,
 		.field_pos = 24,
 		.min_field_value = 1,
 	},
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 90d09eddd5b2..351a4de1b1e2 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -498,6 +498,8 @@ CPU_LE(	bic	x0, x0, #(3 << 24)	)	// Clear the EE and E0E bits for EL1
 	orr	x0, x0, #ICC_SRE_EL2_ENABLE	// Set ICC_SRE_EL2.Enable==1
 	msr_s	ICC_SRE_EL2, x0
 	isb					// Make sure SRE is now set
+	mrs_s	x0, ICC_SRE_EL2			// Read SRE back,
+	tbz	x0, #0, 3f			// and check that it sticks
 	msr_s	ICH_HCR_EL2, xzr		// Reset ICC_HCR_EL2 to defaults
 
 3:
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 5c7e920e4861..ff5292c6277c 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -16,6 +16,9 @@ menuconfig VIRTUALIZATION
 
 if VIRTUALIZATION
 
+config KVM_ARM_VGIC_V3
+	bool
+
 config KVM
 	bool "Kernel-based Virtual Machine (KVM) support"
 	depends on OF
@@ -31,6 +34,7 @@ config KVM
 	select KVM_VFIO
 	select HAVE_KVM_EVENTFD
 	select HAVE_KVM_IRQFD
+	select KVM_ARM_VGIC_V3
 	---help---
 	  Support hosting virtualized guest machines.