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 <mikel...@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 6bd8439..988eda5 100644
--- a/arch/arm64/hyperv/Makefile
+++ b/arch/arm64/hyperv/Makefile
@@ -1,2 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0
-obj-y          := hv_init.o hv_hvc.o
+obj-y          := hv_init.o hv_hvc.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 <mikel...@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

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