[PATCH v6 05/10] arm64: hyperv: Add interrupt handlers for VMbus and stimer

[Michael Kelley <mikelley@microsoft.com>]

Add ARM64-specific code to set up and handle the interrupts
generated by Hyper-V for VMbus messages and for stimer expiration.

This code is architecture dependent and is mostly driven by
architecture independent code in the VMbus driver and the
Hyper-V timer clocksource driver.

This code is built only when CONFIG_HYPERV is enabled.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
---
 arch/arm64/hyperv/Makefile   |   2 +-
 arch/arm64/hyperv/mshyperv.c | 139 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 140 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm64/hyperv/mshyperv.c

diff --git a/arch/arm64/hyperv/Makefile b/arch/arm64/hyperv/Makefile
index 1697d30..87c31c0 100644
--- a/arch/arm64/hyperv/Makefile
+++ b/arch/arm64/hyperv/Makefile
@@ -1,2 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0
-obj-y		:= hv_core.o
+obj-y		:= hv_core.o mshyperv.o
diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
new file mode 100644
index 0000000..ae6ece6
--- /dev/null
+++ b/arch/arm64/hyperv/mshyperv.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Core routines for interacting with Microsoft's Hyper-V hypervisor,
+ * including setting up VMbus and STIMER interrupts, and handling
+ * crashes and kexecs. These interactions are through a set of
+ * static "handler" variables set by the architecture independent
+ * VMbus and STIMER drivers.
+ *
+ * Copyright (C) 2019, Microsoft, Inc.
+ *
+ * Author : Michael Kelley <mikelley@microsoft.com>
+ */
+
+#include <linux/types.h>
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/kexec.h>
+#include <linux/acpi.h>
+#include <linux/ptrace.h>
+#include <asm/hyperv-tlfs.h>
+#include <asm/mshyperv.h>
+
+static void (*vmbus_handler)(void);
+static void (*hv_stimer0_handler)(void);
+
+static int vmbus_irq;
+static long __percpu *vmbus_evt;
+static long __percpu *stimer0_evt;
+
+irqreturn_t hyperv_vector_handler(int irq, void *dev_id)
+{
+	vmbus_handler();
+	return IRQ_HANDLED;
+}
+
+/* Must be done just once */
+void hv_setup_vmbus_irq(void (*handler)(void))
+{
+	int result;
+
+	vmbus_handler = handler;
+	vmbus_irq = acpi_register_gsi(NULL, HYPERVISOR_CALLBACK_VECTOR,
+				 ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH);
+	if (vmbus_irq <= 0) {
+		pr_err("Can't register Hyper-V VMBus GSI. Error %d",
+			vmbus_irq);
+		vmbus_irq = 0;
+		return;
+	}
+	vmbus_evt = alloc_percpu(long);
+	result = request_percpu_irq(vmbus_irq, hyperv_vector_handler,
+			"Hyper-V VMbus", vmbus_evt);
+	if (result) {
+		pr_err("Can't request Hyper-V VMBus IRQ %d. Error %d",
+			vmbus_irq, result);
+		free_percpu(vmbus_evt);
+		acpi_unregister_gsi(vmbus_irq);
+		vmbus_irq = 0;
+	}
+}
+EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
+
+/* Must be done just once */
+void hv_remove_vmbus_irq(void)
+{
+	if (vmbus_irq) {
+		free_percpu_irq(vmbus_irq, vmbus_evt);
+		free_percpu(vmbus_evt);
+		acpi_unregister_gsi(vmbus_irq);
+	}
+}
+EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
+
+/* Must be done by each CPU */
+void hv_enable_vmbus_irq(void)
+{
+	enable_percpu_irq(vmbus_irq, 0);
+}
+EXPORT_SYMBOL_GPL(hv_enable_vmbus_irq);
+
+/* Must be done by each CPU */
+void hv_disable_vmbus_irq(void)
+{
+	disable_percpu_irq(vmbus_irq);
+}
+EXPORT_SYMBOL_GPL(hv_disable_vmbus_irq);
+
+/* Routines to do per-architecture handling of STIMER0 when in Direct Mode */
+
+static irqreturn_t hv_stimer0_vector_handler(int irq, void *dev_id)
+{
+	if (hv_stimer0_handler)
+		hv_stimer0_handler();
+	return IRQ_HANDLED;
+}
+
+int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void))
+{
+	int localirq;
+	int result;
+
+	localirq = acpi_register_gsi(NULL, HV_STIMER0_IRQNR,
+			ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH);
+	if (localirq <= 0) {
+		pr_err("Can't register Hyper-V stimer0 GSI. Error %d",
+			localirq);
+		*irq = 0;
+		return -1;
+	}
+	stimer0_evt = alloc_percpu(long);
+	result = request_percpu_irq(localirq, hv_stimer0_vector_handler,
+					 "Hyper-V stimer0", stimer0_evt);
+	if (result) {
+		pr_err("Can't request Hyper-V stimer0 IRQ %d. Error %d",
+			localirq, result);
+		free_percpu(stimer0_evt);
+		acpi_unregister_gsi(localirq);
+		*irq = 0;
+		return -1;
+	}
+
+	hv_stimer0_handler = handler;
+	*vector = HV_STIMER0_IRQNR;
+	*irq = localirq;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hv_setup_stimer0_irq);
+
+void hv_remove_stimer0_irq(int irq)
+{
+	hv_stimer0_handler = NULL;
+	if (irq) {
+		free_percpu_irq(irq, stimer0_evt);
+		free_percpu(stimer0_evt);
+		acpi_unregister_gsi(irq);
+	}
+}
+EXPORT_SYMBOL_GPL(hv_remove_stimer0_irq);
-- 
1.8.3.1