aboutsummaryrefslogtreecommitdiffstats
path: root/linux-2.4.26-xen-sparse/arch/xen/kernel/evtchn.c
diff options
context:
space:
mode:
Diffstat (limited to 'linux-2.4.26-xen-sparse/arch/xen/kernel/evtchn.c')
-rw-r--r--linux-2.4.26-xen-sparse/arch/xen/kernel/evtchn.c477
1 files changed, 477 insertions, 0 deletions
diff --git a/linux-2.4.26-xen-sparse/arch/xen/kernel/evtchn.c b/linux-2.4.26-xen-sparse/arch/xen/kernel/evtchn.c
new file mode 100644
index 0000000000..fc6f22fc34
--- /dev/null
+++ b/linux-2.4.26-xen-sparse/arch/xen/kernel/evtchn.c
@@ -0,0 +1,477 @@
+/******************************************************************************
+ * evtchn.c
+ *
+ * Communication via Xen event channels.
+ *
+ * Copyright (c) 2002-2004, K A Fraser
+ */
+
+#include <linux/config.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/kernel_stat.h>
+#include <asm/atomic.h>
+#include <asm/system.h>
+#include <asm/ptrace.h>
+#include <asm/synch_bitops.h>
+#include <asm/ctrl_if.h>
+#include <asm/hypervisor.h>
+#include <asm/hypervisor-ifs/event_channel.h>
+#include <asm/hypervisor-ifs/physdev.h>
+
+/*
+ * 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.
+ */
+static spinlock_t irq_mapping_update_lock;
+
+/* IRQ <-> event-channel mappings. */
+static int evtchn_to_irq[NR_EVENT_CHANNELS];
+static int irq_to_evtchn[NR_IRQS];
+
+/* IRQ <-> VIRQ mapping. */
+static int virq_to_irq[NR_VIRQS];
+
+/* Reference counts for bindings to IRQs. */
+static int irq_bindcount[NR_IRQS];
+
+/* Bitmap indicating which PIRQs require Xen to be notified on unmask. */
+static unsigned long pirq_needs_unmask_notify[NR_PIRQS/sizeof(unsigned long)];
+
+/* Upcall to generic IRQ layer. */
+extern asmlinkage unsigned int do_IRQ(int irq, struct pt_regs *regs);
+
+#define VALID_EVTCHN(_chn) ((_chn) != -1)
+
+void evtchn_do_upcall(struct pt_regs *regs)
+{
+ unsigned long l1, l2;
+ unsigned int l1i, l2i, port;
+ int irq;
+ unsigned long flags;
+ shared_info_t *s = HYPERVISOR_shared_info;
+
+ local_irq_save(flags);
+
+ while ( s->vcpu_data[0].evtchn_upcall_pending )
+ {
+ s->vcpu_data[0].evtchn_upcall_pending = 0;
+ /* NB. No need for a barrier here -- XCHG is a barrier on x86. */
+ l1 = xchg(&s->evtchn_pending_sel, 0);
+ while ( (l1i = ffs(l1)) != 0 )
+ {
+ l1i--;
+ l1 &= ~(1 << l1i);
+
+ l2 = s->evtchn_pending[l1i] & ~s->evtchn_mask[l1i];
+ while ( (l2i = ffs(l2)) != 0 )
+ {
+ l2i--;
+ l2 &= ~(1 << l2i);
+
+ port = (l1i << 5) + l2i;
+ if ( (irq = evtchn_to_irq[port]) != -1 )
+ do_IRQ(irq, regs);
+ else
+ evtchn_device_upcall(port);
+ }
+ }
+ }
+
+ local_irq_restore(flags);
+}
+
+
+static int find_unbound_irq(void)
+{
+ int irq;
+
+ for ( irq = 0; irq < NR_IRQS; irq++ )
+ if ( irq_bindcount[irq] == 0 )
+ break;
+
+ if ( irq == NR_IRQS )
+ panic("No available IRQ to bind to: increase NR_IRQS!\n");
+
+ return irq;
+}
+
+int bind_virq_to_irq(int virq)
+{
+ evtchn_op_t op;
+ int evtchn, irq;
+
+ spin_lock(&irq_mapping_update_lock);
+
+ if ( (irq = virq_to_irq[virq]) == -1 )
+ {
+ op.cmd = EVTCHNOP_bind_virq;
+ op.u.bind_virq.virq = virq;
+ if ( HYPERVISOR_event_channel_op(&op) != 0 )
+ panic("Failed to bind virtual IRQ %d\n", virq);
+ evtchn = op.u.bind_virq.port;
+
+ irq = find_unbound_irq();
+ evtchn_to_irq[evtchn] = irq;
+ irq_to_evtchn[irq] = evtchn;
+
+ virq_to_irq[virq] = irq;
+ }
+
+ irq_bindcount[irq]++;
+
+ spin_unlock(&irq_mapping_update_lock);
+
+ return irq;
+}
+
+void unbind_virq_from_irq(int virq)
+{
+ evtchn_op_t op;
+ int irq = virq_to_irq[virq];
+ int evtchn = irq_to_evtchn[irq];
+
+ spin_lock(&irq_mapping_update_lock);
+
+ if ( --irq_bindcount[irq] == 0 )
+ {
+ op.cmd = EVTCHNOP_close;
+ op.u.close.dom = DOMID_SELF;
+ op.u.close.port = evtchn;
+ if ( HYPERVISOR_event_channel_op(&op) != 0 )
+ panic("Failed to unbind virtual IRQ %d\n", virq);
+
+ evtchn_to_irq[evtchn] = -1;
+ irq_to_evtchn[irq] = -1;
+ virq_to_irq[virq] = -1;
+ }
+
+ spin_unlock(&irq_mapping_update_lock);
+}
+
+int bind_evtchn_to_irq(int evtchn)
+{
+ int irq;
+
+ spin_lock(&irq_mapping_update_lock);
+
+ if ( (irq = evtchn_to_irq[evtchn]) == -1 )
+ {
+ irq = find_unbound_irq();
+ evtchn_to_irq[evtchn] = irq;
+ irq_to_evtchn[irq] = evtchn;
+ }
+
+ irq_bindcount[irq]++;
+
+ spin_unlock(&irq_mapping_update_lock);
+
+ return irq;
+}
+
+void unbind_evtchn_from_irq(int evtchn)
+{
+ int irq = evtchn_to_irq[evtchn];
+
+ spin_lock(&irq_mapping_update_lock);
+
+ if ( --irq_bindcount[irq] == 0 )
+ {
+ evtchn_to_irq[evtchn] = -1;
+ irq_to_evtchn[irq] = -1;
+ }
+
+ spin_unlock(&irq_mapping_update_lock);
+}
+
+
+/*
+ * Interface to generic handling in irq.c
+ */
+
+static unsigned int startup_dynirq(unsigned int irq)
+{
+ unmask_evtchn(irq_to_evtchn[irq]);
+ return 0;
+}
+
+static void shutdown_dynirq(unsigned int irq)
+{
+ mask_evtchn(irq_to_evtchn[irq]);
+}
+
+static void enable_dynirq(unsigned int irq)
+{
+ unmask_evtchn(irq_to_evtchn[irq]);
+}
+
+static void disable_dynirq(unsigned int irq)
+{
+ mask_evtchn(irq_to_evtchn[irq]);
+}
+
+static void ack_dynirq(unsigned int irq)
+{
+ mask_evtchn(irq_to_evtchn[irq]);
+ clear_evtchn(irq_to_evtchn[irq]);
+}
+
+static void end_dynirq(unsigned int irq)
+{
+ if ( !(irq_desc[irq].status & IRQ_DISABLED) )
+ unmask_evtchn(irq_to_evtchn[irq]);
+}
+
+static struct hw_interrupt_type dynirq_type = {
+ "Dynamic-irq",
+ startup_dynirq,
+ shutdown_dynirq,
+ enable_dynirq,
+ disable_dynirq,
+ ack_dynirq,
+ end_dynirq,
+ NULL
+};
+
+static inline void pirq_unmask_notify(int pirq)
+{
+ physdev_op_t op;
+ if ( unlikely(test_bit(pirq, &pirq_needs_unmask_notify[0])) )
+ {
+ op.cmd = PHYSDEVOP_IRQ_UNMASK_NOTIFY;
+ (void)HYPERVISOR_physdev_op(&op);
+ }
+}
+
+static inline void pirq_query_unmask(int pirq)
+{
+ physdev_op_t op;
+ op.cmd = PHYSDEVOP_IRQ_STATUS_QUERY;
+ op.u.irq_status_query.irq = pirq;
+ (void)HYPERVISOR_physdev_op(&op);
+ clear_bit(pirq, &pirq_needs_unmask_notify[0]);
+ if ( op.u.irq_status_query.flags & PHYSDEVOP_IRQ_NEEDS_UNMASK_NOTIFY )
+ set_bit(pirq, &pirq_needs_unmask_notify[0]);
+}
+
+/*
+ * On startup, if there is no action associated with the IRQ then we are
+ * probing. In this case we should not share with others as it will confuse us.
+ */
+#define probing_irq(_irq) (irq_desc[(_irq)].action == NULL)
+
+static unsigned int startup_pirq(unsigned int irq)
+{
+ evtchn_op_t op;
+ int evtchn;
+
+ op.cmd = EVTCHNOP_bind_pirq;
+ op.u.bind_pirq.pirq = irq;
+ /* NB. We are happy to share unless we are probing. */
+ op.u.bind_pirq.flags = probing_irq(irq) ? 0 : BIND_PIRQ__WILL_SHARE;
+ if ( HYPERVISOR_event_channel_op(&op) != 0 )
+ {
+ if ( !probing_irq(irq) ) /* Some failures are expected when probing. */
+ printk(KERN_INFO "Failed to obtain physical IRQ %d\n", irq);
+ return 0;
+ }
+ evtchn = op.u.bind_pirq.port;
+
+ pirq_query_unmask(irq_to_pirq(irq));
+
+ evtchn_to_irq[evtchn] = irq;
+ irq_to_evtchn[irq] = evtchn;
+
+ unmask_evtchn(evtchn);
+ pirq_unmask_notify(irq_to_pirq(irq));
+
+ return 0;
+}
+
+static void shutdown_pirq(unsigned int irq)
+{
+ evtchn_op_t op;
+ int evtchn = irq_to_evtchn[irq];
+
+ if ( !VALID_EVTCHN(evtchn) )
+ return;
+
+ mask_evtchn(evtchn);
+
+ op.cmd = EVTCHNOP_close;
+ op.u.close.dom = DOMID_SELF;
+ op.u.close.port = evtchn;
+ if ( HYPERVISOR_event_channel_op(&op) != 0 )
+ panic("Failed to unbind physical IRQ %d\n", irq);
+
+ evtchn_to_irq[evtchn] = -1;
+ irq_to_evtchn[irq] = -1;
+}
+
+static void enable_pirq(unsigned int irq)
+{
+ int evtchn = irq_to_evtchn[irq];
+ if ( !VALID_EVTCHN(evtchn) )
+ return;
+ unmask_evtchn(evtchn);
+ pirq_unmask_notify(irq_to_pirq(irq));
+}
+
+static void disable_pirq(unsigned int irq)
+{
+ int evtchn = irq_to_evtchn[irq];
+ if ( !VALID_EVTCHN(evtchn) )
+ return;
+ mask_evtchn(evtchn);
+}
+
+static void ack_pirq(unsigned int irq)
+{
+ int evtchn = irq_to_evtchn[irq];
+ if ( !VALID_EVTCHN(evtchn) )
+ return;
+ mask_evtchn(evtchn);
+ clear_evtchn(evtchn);
+}
+
+static void end_pirq(unsigned int irq)
+{
+ int evtchn = irq_to_evtchn[irq];
+ if ( !VALID_EVTCHN(evtchn) )
+ return;
+ if ( !(irq_desc[irq].status & IRQ_DISABLED) )
+ {
+ unmask_evtchn(evtchn);
+ pirq_unmask_notify(irq_to_pirq(irq));
+ }
+}
+
+static struct hw_interrupt_type pirq_type = {
+ "Phys-irq",
+ startup_pirq,
+ shutdown_pirq,
+ enable_pirq,
+ disable_pirq,
+ ack_pirq,
+ end_pirq,
+ NULL
+};
+
+static void misdirect_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+ /* nothing */
+}
+
+static struct irqaction misdirect_action = {
+ misdirect_interrupt,
+ SA_INTERRUPT,
+ 0,
+ "misdirect",
+ NULL,
+ NULL
+};
+
+void irq_suspend(void)
+{
+ int virq, irq, evtchn;
+
+ /* Unbind VIRQs from event channels. */
+ for ( virq = 0; virq < NR_VIRQS; virq++ )
+ {
+ if ( (irq = virq_to_irq[virq]) == -1 )
+ continue;
+ evtchn = irq_to_evtchn[irq];
+
+ /* Mark the event channel as unused in our table. */
+ evtchn_to_irq[evtchn] = -1;
+ irq_to_evtchn[irq] = -1;
+ }
+
+ /*
+ * We should now be unbound from all event channels. Stale bindings to
+ * PIRQs and/or inter-domain event channels will cause us to barf here.
+ */
+ for ( evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++ )
+ if ( evtchn_to_irq[evtchn] != -1 )
+ panic("Suspend attempted while bound to evtchn %d.\n", evtchn);
+}
+
+
+void irq_resume(void)
+{
+ evtchn_op_t op;
+ int virq, irq, evtchn;
+
+ for ( evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++ )
+ mask_evtchn(evtchn); /* New event-channel space is not 'live' yet. */
+
+ for ( virq = 0; virq < NR_VIRQS; virq++ )
+ {
+ if ( (irq = virq_to_irq[virq]) == -1 )
+ continue;
+
+ /* Get a new binding from Xen. */
+ op.cmd = EVTCHNOP_bind_virq;
+ op.u.bind_virq.virq = virq;
+ if ( HYPERVISOR_event_channel_op(&op) != 0 )
+ panic("Failed to bind virtual IRQ %d\n", virq);
+ evtchn = op.u.bind_virq.port;
+
+ /* Record the new mapping. */
+ evtchn_to_irq[evtchn] = irq;
+ irq_to_evtchn[irq] = evtchn;
+
+ /* Ready for use. */
+ unmask_evtchn(evtchn);
+ }
+}
+
+void __init init_IRQ(void)
+{
+ int i;
+
+ spin_lock_init(&irq_mapping_update_lock);
+
+ /* No VIRQ -> IRQ mappings. */
+ for ( i = 0; i < NR_VIRQS; i++ )
+ virq_to_irq[i] = -1;
+
+ /* No event-channel -> IRQ mappings. */
+ for ( i = 0; i < NR_EVENT_CHANNELS; i++ )
+ {
+ evtchn_to_irq[i] = -1;
+ mask_evtchn(i); /* No event channels are 'live' right now. */
+ }
+
+ /* No IRQ -> event-channel mappings. */
+ for ( i = 0; i < NR_IRQS; i++ )
+ irq_to_evtchn[i] = -1;
+
+ for ( i = 0; i < NR_DYNIRQS; i++ )
+ {
+ /* Dynamic IRQ space is currently unbound. Zero the refcnts. */
+ irq_bindcount[dynirq_to_irq(i)] = 0;
+
+ irq_desc[dynirq_to_irq(i)].status = IRQ_DISABLED;
+ irq_desc[dynirq_to_irq(i)].action = 0;
+ irq_desc[dynirq_to_irq(i)].depth = 1;
+ irq_desc[dynirq_to_irq(i)].handler = &dynirq_type;
+ }
+
+ for ( i = 0; i < NR_PIRQS; i++ )
+ {
+ /* Phys IRQ space is statically bound (1:1 mapping). Nail refcnts. */
+ irq_bindcount[pirq_to_irq(i)] = 1;
+
+ irq_desc[pirq_to_irq(i)].status = IRQ_DISABLED;
+ irq_desc[pirq_to_irq(i)].action = 0;
+ irq_desc[pirq_to_irq(i)].depth = 1;
+ irq_desc[pirq_to_irq(i)].handler = &pirq_type;
+ }
+
+ (void)setup_irq(bind_virq_to_irq(VIRQ_MISDIRECT), &misdirect_action);
+
+ /* This needs to be done early, but after the IRQ subsystem is alive. */
+ ctrl_if_init();
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-23 15:02:04 +0000