xen/arm: receive Xen events on ARM

Compile events.c on ARM.
Parse, map and enable the IRQ to get event notifications from the device
tree (node "/xen").

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

7 files changed, 69 insertions, 4 deletions

diff --git a/arch/arm/include/asm/xen/events.h b/arch/arm/include/asm/xen/events.h
new file mode 100644
index 000000000000..94b4e9020b02
--- /dev/null
+++ b/arch/arm/include/asm/xen/events.h
@@ -0,0 +1,18 @@
+#ifndef _ASM_ARM_XEN_EVENTS_H
+#define _ASM_ARM_XEN_EVENTS_H
+
+#include <asm/ptrace.h>
+
+enum ipi_vector {
+        XEN_PLACEHOLDER_VECTOR,
+
+        /* Xen IPIs go here */
+        XEN_NR_IPIS,
+};
+
+static inline int xen_irqs_disabled(struct pt_regs *regs)
+{
+        return raw_irqs_disabled_flags(regs->ARM_cpsr);
+}
+
+#endif /* _ASM_ARM_XEN_EVENTS_H */
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 036a4d84e861..bad67ad43c2d 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -1,4 +1,5 @@
 #include <xen/xen.h>
+#include <xen/events.h>
 #include <xen/grant_table.h>
 #include <xen/hvm.h>
 #include <xen/interface/xen.h>
@@ -9,6 +10,8 @@
 #include <xen/xenbus.h>
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
@@ -33,6 +36,8 @@ EXPORT_SYMBOL_GPL(xen_have_vector_callback);
 int xen_platform_pci_unplug = XEN_UNPLUG_ALL;
 EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
 
+static __read_mostly int xen_events_irq = -1;
+
 int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
                                unsigned long addr,
                                unsigned long mfn, int nr,
@@ -74,6 +79,9 @@ static int __init xen_guest_init(void)
         if (of_address_to_resource(node, GRANT_TABLE_PHYSADDR, &res))
                 return 0;
         xen_hvm_resume_frames = res.start >> PAGE_SHIFT;
+        xen_events_irq = irq_of_parse_and_map(node, 0);
+        pr_info("Xen %s support found, events_irq=%d gnttab_frame_pfn=%lx\n",
+                        version, xen_events_irq, xen_hvm_resume_frames);
         xen_domain_type = XEN_HVM_DOMAIN;
 
         xen_setup_features();
@@ -115,3 +123,28 @@ static int __init xen_guest_init(void)
         return 0;
 }
 core_initcall(xen_guest_init);
+
+static irqreturn_t xen_arm_callback(int irq, void *arg)
+{
+        xen_hvm_evtchn_do_upcall();
+        return IRQ_HANDLED;
+}
+
+static int __init xen_init_events(void)
+{
+        if (!xen_domain() || xen_events_irq < 0)
+                return -ENODEV;
+
+        xen_init_IRQ();
+
+        if (request_percpu_irq(xen_events_irq, xen_arm_callback,
+                        "events", xen_vcpu)) {
+                pr_err("Error requesting IRQ %d\n", xen_events_irq);
+                return -EINVAL;
+        }
+
+        enable_percpu_irq(xen_events_irq, 0);
+
+        return 0;
+}
+postcore_initcall(xen_init_events);
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 47b3acdc2ac5..689a4c9da866 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -33,6 +33,7 @@
 #include <linux/memblock.h>
 
 #include <xen/xen.h>
+#include <xen/events.h>
 #include <xen/interface/xen.h>
 #include <xen/interface/version.h>
 #include <xen/interface/physdev.h>
diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
index 157337657971..01a4dc015ae1 100644
--- a/arch/x86/xen/irq.c
+++ b/arch/x86/xen/irq.c
@@ -5,6 +5,7 @@
 #include <xen/interface/xen.h>
 #include <xen/interface/sched.h>
 #include <xen/interface/vcpu.h>
+#include <xen/events.h>
 
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index bb5a8105ea86..a95b41744ad0 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -35,7 +35,6 @@ void xen_set_pat(u64);
 
 char * __init xen_memory_setup(void);
 void __init xen_arch_setup(void);
-void __init xen_init_IRQ(void);
 void xen_enable_sysenter(void);
 void xen_enable_syscall(void);
 void xen_vcpu_restore(void);
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index c60d1629c916..8672211555bb 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -31,14 +31,16 @@
 #include <linux/irqnr.h>
 #include <linux/pci.h>
 
+#ifdef CONFIG_X86
 #include <asm/desc.h>
 #include <asm/ptrace.h>
 #include <asm/irq.h>
 #include <asm/idle.h>
 #include <asm/io_apic.h>
-#include <asm/sync_bitops.h>
 #include <asm/xen/page.h>
 #include <asm/xen/pci.h>
+#endif
+#include <asm/sync_bitops.h>
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
 
@@ -50,6 +52,9 @@
 #include <xen/interface/event_channel.h>
 #include <xen/interface/hvm/hvm_op.h>
 #include <xen/interface/hvm/params.h>
+#include <xen/interface/physdev.h>
+#include <xen/interface/sched.h>
+#include <asm/hw_irq.h>
 
 /*
  * This lock protects updates to the following mapping and reference-count
@@ -1386,7 +1391,9 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
 {
         struct pt_regs *old_regs = set_irq_regs(regs);
 
+#ifdef CONFIG_X86
         exit_idle();
+#endif
         irq_enter();
 
         __xen_evtchn_do_upcall();
@@ -1795,9 +1802,9 @@ void xen_callback_vector(void)
 void xen_callback_vector(void) {}
 #endif
 
-void __init xen_init_IRQ(void)
+void xen_init_IRQ(void)
 {
-        int i, rc;
+        int i;
 
         evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
                                     GFP_KERNEL);
@@ -1813,6 +1820,7 @@ void __init xen_init_IRQ(void)
 
         pirq_needs_eoi = pirq_needs_eoi_flag;
 
+#ifdef CONFIG_X86
         if (xen_hvm_domain()) {
                 xen_callback_vector();
                 native_init_IRQ();
@@ -1820,6 +1828,7 @@ void __init xen_init_IRQ(void)
                  * __acpi_register_gsi can point at the right function */
                 pci_xen_hvm_init();
         } else {
+                int rc;
                 struct physdev_pirq_eoi_gmfn eoi_gmfn;
 
                 irq_ctx_init(smp_processor_id());
@@ -1835,4 +1844,6 @@ void __init xen_init_IRQ(void)
                 } else
                         pirq_needs_eoi = pirq_check_eoi_map;
         }
+#endif
 }
+EXPORT_SYMBOL_GPL(xen_init_IRQ);
diff --git a/include/xen/events.h b/include/xen/events.h
index 04399b28e821..c6bfe01acf6b 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -109,4 +109,6 @@ int xen_irq_from_gsi(unsigned gsi);
 /* Determine whether to ignore this IRQ if it is passed to a guest. */
 int xen_test_irq_shared(int irq);
 
+/* initialize Xen IRQ subsystem */
+void xen_init_IRQ(void);
 #endif  /* _XEN_EVENTS_H */