xen/arm: Release maintenance interrupt when CPU is hot-unplugged

When a CPU is hot-unplugged the maintenance interrupt has to be
released in order to free the memory that was allocated when the CPU
was hotplugged and interrupt requested. The interrupt was requested
using request_irq() which is called from start_secondary->
init_maintenance_interrupt. With this patch the interrupt will be
released when the CPU_DYING event is received by the callback which
is added in gic.c.

Signed-off-by: Mirela Simonovic <mirela.simonovic@aggios.com>
Acked-by: Julien Grall <julien.grall@arm.com>

diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index 653a8151271d18191516bd6afc57256f7d4bd5bb..5474030386cc11a9a58ab8b93107831c65daeae6 100644 (file)
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -27,6 +27,8 @@
 #include <xen/list.h>
 #include <xen/device_tree.h>
 #include <xen/acpi.h>
+#include <xen/cpu.h>
+#include <xen/notifier.h>
 #include <asm/p2m.h>
 #include <asm/domain.h>
 #include <asm/platform.h>
@@ -462,6 +464,35 @@ int gic_iomem_deny_access(const struct domain *d)
     return gic_hw_ops->iomem_deny_access(d);
 }
 
+static int cpu_gic_callback(struct notifier_block *nfb,
+                            unsigned long action,
+                            void *hcpu)
+{
+    switch ( action )
+    {
+    case CPU_DYING:
+        /* This is reverting the work done in init_maintenance_interrupt */
+        release_irq(gic_hw_ops->info->maintenance_irq, NULL);
+        break;
+    default:
+        break;
+    }
+
+    return NOTIFY_DONE;
+}
+
+static struct notifier_block cpu_gic_nfb = {
+    .notifier_call = cpu_gic_callback,
+};
+
+static int __init cpu_gic_notifier_init(void)
+{
+    register_cpu_notifier(&cpu_gic_nfb);
+
+    return 0;
+}
+__initcall(cpu_gic_notifier_init);
+
 /*
  * Local variables:
  * mode: C