[PATCH 07/12] xen/events: add struct evtchn_ops for the low-level port operations

[David Vrabel <david.vrabel@citrix.com>]

From: David Vrabel <david.vrabel@citrix.com>

evtchn_ops contains the low-level operations that access the shared
data structures.  This allows alternate ABIs to be supported.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
 drivers/xen/events/events.c          |    4 ++
 drivers/xen/events/events_internal.h |   62 +++++++++++++++++++++++++++++----
 drivers/xen/events/n-level.c         |   32 +++++++++++++----
 3 files changed, 82 insertions(+), 16 deletions(-)

diff --git a/drivers/xen/events/events.c b/drivers/xen/events/events.c
index 8d5a5cf..dff8134 100644
--- a/drivers/xen/events/events.c
+++ b/drivers/xen/events/events.c
@@ -60,6 +60,8 @@
 
 #include "events_internal.h"
 
+const struct evtchn_ops *evtchn_ops;
+
 /*
  * This lock protects updates to the following mapping and reference-count
  * arrays. The lock does not need to be acquired to read the mapping tables.
@@ -1497,6 +1499,8 @@ void __init xen_init_IRQ(void)
 {
 	int i;
 
+	xen_evtchn_init_nlevel();
+
 	evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
 				    GFP_KERNEL);
 	BUG_ON(!evtchn_to_irq);
diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
index 79ac70b..513c34d 100644
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -54,21 +54,67 @@ struct irq_info {
 #define PIRQ_NEEDS_EOI	(1 << 0)
 #define PIRQ_SHAREABLE	(1 << 1)
 
+struct evtchn_ops {
+	void (*bind_to_cpu)(struct irq_info *info, int cpu);
+
+	void (*clear_pending)(int port);
+	void (*set_pending)(int port);
+	bool (*is_pending)(int port);
+	bool (*test_and_set_mask)(int port);
+	void (*mask)(int port);
+	void (*unmask)(int port);
+
+	void (*handle_events)(int cpu);
+};
+
+extern const struct evtchn_ops *evtchn_ops;
+
 extern int *evtchn_to_irq;
 
 struct irq_info *info_for_irq(unsigned irq);
 unsigned cpu_from_irq(unsigned irq);
 unsigned cpu_from_evtchn(unsigned int evtchn);
 
-void xen_evtchn_port_bind_to_cpu(struct irq_info *info, int cpu);
+static inline void xen_evtchn_port_bind_to_cpu(struct irq_info *info, int cpu)
+{
+	evtchn_ops->bind_to_cpu(info, cpu);
+}
+
+static inline void clear_evtchn(int port)
+{
+	evtchn_ops->clear_pending(port);
+}
+
+static inline void set_evtchn(int port)
+{
+	evtchn_ops->set_pending(port);
+}
+
+static inline bool test_evtchn(int port)
+{
+	return evtchn_ops->is_pending(port);
+}
+
+static inline bool test_and_set_mask(int port)
+{
+	return evtchn_ops->test_and_set_mask(port);
+}
+
+static inline void mask_evtchn(int port)
+{
+	return evtchn_ops->mask(port);
+}
+
+static inline void unmask_evtchn(int port)
+{
+	return evtchn_ops->unmask(port);
+}
 
-void clear_evtchn(int port);
-void set_evtchn(int port);
-int test_evtchn(int port);
-int test_and_set_mask(int port);
-void mask_evtchn(int port);
-void unmask_evtchn(int port);
+static inline void xen_evtchn_handle_events(int cpu)
+{
+	return evtchn_ops->handle_events(cpu);
+}
 
-void xen_evtchn_handle_events(int cpu);
+void xen_evtchn_init_nlevel(void);
 
 #endif /* #ifndef __EVENTS_INTERNAL_H__ */
diff --git a/drivers/xen/events/n-level.c b/drivers/xen/events/n-level.c
index 05762d5..a449b69 100644
--- a/drivers/xen/events/n-level.c
+++ b/drivers/xen/events/n-level.c
@@ -39,43 +39,43 @@
 static DEFINE_PER_CPU(xen_ulong_t [NR_EVENT_CHANNELS/BITS_PER_EVTCHN_WORD],
 		      cpu_evtchn_mask);
 
-void xen_evtchn_port_bind_to_cpu(struct irq_info *info, int cpu)
+static void nlevel_bind_to_cpu(struct irq_info *info, int cpu)
 {
 	clear_bit(info->evtchn, BM(per_cpu(cpu_evtchn_mask, info->cpu)));
 	set_bit(info->evtchn, BM(per_cpu(cpu_evtchn_mask, cpu)));
 }
 
-void clear_evtchn(int port)
+static void nlevel_clear_pending(int port)
 {
 	struct shared_info *s = HYPERVISOR_shared_info;
 	sync_clear_bit(port, BM(&s->evtchn_pending[0]));
 }
 
-void set_evtchn(int port)
+static void nlevel_set_pending(int port)
 {
 	struct shared_info *s = HYPERVISOR_shared_info;
 	sync_set_bit(port, BM(&s->evtchn_pending[0]));
 }
 
-int test_evtchn(int port)
+static bool nlevel_is_pending(int port)
 {
 	struct shared_info *s = HYPERVISOR_shared_info;
 	return sync_test_bit(port, BM(&s->evtchn_pending[0]));
 }
 
-int test_and_set_mask(int port)
+static bool nlevel_test_and_set_mask(int port)
 {
 	struct shared_info *s = HYPERVISOR_shared_info;
 	return sync_test_and_set_bit(port, BM(&s->evtchn_mask[0]));
 }
 
-void mask_evtchn(int port)
+static void nlevel_mask(int port)
 {
 	struct shared_info *s = HYPERVISOR_shared_info;
 	sync_set_bit(port, BM(&s->evtchn_mask[0]));
 }
 
-void unmask_evtchn(int port)
+static void nlevel_unmask(int port)
 {
 	struct shared_info *s = HYPERVISOR_shared_info;
 	unsigned int cpu = get_cpu();
@@ -141,7 +141,7 @@ static inline xen_ulong_t active_evtchns(unsigned int cpu,
  * a bitset of words which contain pending event bits.  The second
  * level is a bitset of pending events themselves.
  */
-void xen_evtchn_handle_events(int cpu)
+static void nlevel_handle_events(int cpu)
 {
 	xen_ulong_t pending_words;
 	int start_word_idx, start_bit_idx;
@@ -313,3 +313,19 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 
 	return IRQ_HANDLED;
 }
+
+static const struct evtchn_ops evtchn_ops_nlevel = {
+	.bind_to_cpu       = nlevel_bind_to_cpu,
+	.clear_pending     = nlevel_clear_pending,
+	.set_pending       = nlevel_set_pending,
+	.is_pending        = nlevel_is_pending,
+	.test_and_set_mask = nlevel_test_and_set_mask,
+	.mask              = nlevel_mask,
+	.unmask            = nlevel_unmask,
+	.handle_events     = nlevel_handle_events,
+};
+
+void __init xen_evtchn_init_nlevel(void)
+{
+	evtchn_ops = &evtchn_ops_nlevel;
+}
-- 
1.7.2.5