ia64/pv_ops/xen: implement xen pv_irq_ops.

implement xen pv_irq_ops to paravirtualize irq handling
with xen event channel.

Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Akio Takebe <takebe_akio@jp.fujitsu.com>
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 435 insertions, 0 deletions

diff --git a/arch/ia64/xen/irq_xen.c b/arch/ia64/xen/irq_xen.c
new file mode 100644
index 000000000000..af93aadb68bb
--- /dev/null
+++ b/arch/ia64/xen/irq_xen.c
@@ -0,0 +1,435 @@
+/******************************************************************************
+ * arch/ia64/xen/irq_xen.c
+ *
+ * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
+ *                    VA Linux Systems Japan K.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include <linux/cpu.h>
+
+#include <xen/interface/xen.h>
+#include <xen/interface/callback.h>
+#include <xen/events.h>
+
+#include <asm/xen/privop.h>
+
+#include "irq_xen.h"
+
+/***************************************************************************
+ * pv_irq_ops
+ * irq operations
+ */
+
+static int
+xen_assign_irq_vector(int irq)
+{
+        struct physdev_irq irq_op;
+
+        irq_op.irq = irq;
+        if (HYPERVISOR_physdev_op(PHYSDEVOP_alloc_irq_vector, &irq_op))
+                return -ENOSPC;
+
+        return irq_op.vector;
+}
+
+static void
+xen_free_irq_vector(int vector)
+{
+        struct physdev_irq irq_op;
+
+        if (vector < IA64_FIRST_DEVICE_VECTOR ||
+            vector > IA64_LAST_DEVICE_VECTOR)
+                return;
+
+        irq_op.vector = vector;
+        if (HYPERVISOR_physdev_op(PHYSDEVOP_free_irq_vector, &irq_op))
+                printk(KERN_WARNING "%s: xen_free_irq_vecotr fail vector=%d\n",
+                       __func__, vector);
+}
+
+
+static DEFINE_PER_CPU(int, timer_irq) = -1;
+static DEFINE_PER_CPU(int, ipi_irq) = -1;
+static DEFINE_PER_CPU(int, resched_irq) = -1;
+static DEFINE_PER_CPU(int, cmc_irq) = -1;
+static DEFINE_PER_CPU(int, cmcp_irq) = -1;
+static DEFINE_PER_CPU(int, cpep_irq) = -1;
+#define NAME_SIZE       15
+static DEFINE_PER_CPU(char[NAME_SIZE], timer_name);
+static DEFINE_PER_CPU(char[NAME_SIZE], ipi_name);
+static DEFINE_PER_CPU(char[NAME_SIZE], resched_name);
+static DEFINE_PER_CPU(char[NAME_SIZE], cmc_name);
+static DEFINE_PER_CPU(char[NAME_SIZE], cmcp_name);
+static DEFINE_PER_CPU(char[NAME_SIZE], cpep_name);
+#undef NAME_SIZE
+
+struct saved_irq {
+        unsigned int irq;
+        struct irqaction *action;
+};
+/* 16 should be far optimistic value, since only several percpu irqs
+ * are registered early.
+ */
+#define MAX_LATE_IRQ    16
+static struct saved_irq saved_percpu_irqs[MAX_LATE_IRQ];
+static unsigned short late_irq_cnt;
+static unsigned short saved_irq_cnt;
+static int xen_slab_ready;
+
+#ifdef CONFIG_SMP
+/* Dummy stub. Though we may check XEN_RESCHEDULE_VECTOR before __do_IRQ,
+ * it ends up to issue several memory accesses upon percpu data and
+ * thus adds unnecessary traffic to other paths.
+ */
+static irqreturn_t
+xen_dummy_handler(int irq, void *dev_id)
+{
+
+        return IRQ_HANDLED;
+}
+
+static struct irqaction xen_ipi_irqaction = {
+        .handler =      handle_IPI,
+        .flags =        IRQF_DISABLED,
+        .name =         "IPI"
+};
+
+static struct irqaction xen_resched_irqaction = {
+        .handler =      xen_dummy_handler,
+        .flags =        IRQF_DISABLED,
+        .name =         "resched"
+};
+
+static struct irqaction xen_tlb_irqaction = {
+        .handler =      xen_dummy_handler,
+        .flags =        IRQF_DISABLED,
+        .name =         "tlb_flush"
+};
+#endif
+
+/*
+ * This is xen version percpu irq registration, which needs bind
+ * to xen specific evtchn sub-system. One trick here is that xen
+ * evtchn binding interface depends on kmalloc because related
+ * port needs to be freed at device/cpu down. So we cache the
+ * registration on BSP before slab is ready and then deal them
+ * at later point. For rest instances happening after slab ready,
+ * we hook them to xen evtchn immediately.
+ *
+ * FIXME: MCA is not supported by far, and thus "nomca" boot param is
+ * required.
+ */
+static void
+__xen_register_percpu_irq(unsigned int cpu, unsigned int vec,
+                        struct irqaction *action, int save)
+{
+        irq_desc_t *desc;
+        int irq = 0;
+
+        if (xen_slab_ready) {
+                switch (vec) {
+                case IA64_TIMER_VECTOR:
+                        snprintf(per_cpu(timer_name, cpu),
+                                 sizeof(per_cpu(timer_name, cpu)),
+                                 "%s%d", action->name, cpu);
+                        irq = bind_virq_to_irqhandler(VIRQ_ITC, cpu,
+                                action->handler, action->flags,
+                                per_cpu(timer_name, cpu), action->dev_id);
+                        per_cpu(timer_irq, cpu) = irq;
+                        break;
+                case IA64_IPI_RESCHEDULE:
+                        snprintf(per_cpu(resched_name, cpu),
+                                 sizeof(per_cpu(resched_name, cpu)),
+                                 "%s%d", action->name, cpu);
+                        irq = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR, cpu,
+                                action->handler, action->flags,
+                                per_cpu(resched_name, cpu), action->dev_id);
+                        per_cpu(resched_irq, cpu) = irq;
+                        break;
+                case IA64_IPI_VECTOR:
+                        snprintf(per_cpu(ipi_name, cpu),
+                                 sizeof(per_cpu(ipi_name, cpu)),
+                                 "%s%d", action->name, cpu);
+                        irq = bind_ipi_to_irqhandler(XEN_IPI_VECTOR, cpu,
+                                action->handler, action->flags,
+                                per_cpu(ipi_name, cpu), action->dev_id);
+                        per_cpu(ipi_irq, cpu) = irq;
+                        break;
+                case IA64_CMC_VECTOR:
+                        snprintf(per_cpu(cmc_name, cpu),
+                                 sizeof(per_cpu(cmc_name, cpu)),
+                                 "%s%d", action->name, cpu);
+                        irq = bind_virq_to_irqhandler(VIRQ_MCA_CMC, cpu,
+                                                      action->handler,
+                                                      action->flags,
+                                                      per_cpu(cmc_name, cpu),
+                                                      action->dev_id);
+                        per_cpu(cmc_irq, cpu) = irq;
+                        break;
+                case IA64_CMCP_VECTOR:
+                        snprintf(per_cpu(cmcp_name, cpu),
+                                 sizeof(per_cpu(cmcp_name, cpu)),
+                                 "%s%d", action->name, cpu);
+                        irq = bind_ipi_to_irqhandler(XEN_CMCP_VECTOR, cpu,
+                                                     action->handler,
+                                                     action->flags,
+                                                     per_cpu(cmcp_name, cpu),
+                                                     action->dev_id);
+                        per_cpu(cmcp_irq, cpu) = irq;
+                        break;
+                case IA64_CPEP_VECTOR:
+                        snprintf(per_cpu(cpep_name, cpu),
+                                 sizeof(per_cpu(cpep_name, cpu)),
+                                 "%s%d", action->name, cpu);
+                        irq = bind_ipi_to_irqhandler(XEN_CPEP_VECTOR, cpu,
+                                                     action->handler,
+                                                     action->flags,
+                                                     per_cpu(cpep_name, cpu),
+                                                     action->dev_id);
+                        per_cpu(cpep_irq, cpu) = irq;
+                        break;
+                case IA64_CPE_VECTOR:
+                case IA64_MCA_RENDEZ_VECTOR:
+                case IA64_PERFMON_VECTOR:
+                case IA64_MCA_WAKEUP_VECTOR:
+                case IA64_SPURIOUS_INT_VECTOR:
+                        /* No need to complain, these aren't supported. */
+                        break;
+                default:
+                        printk(KERN_WARNING "Percpu irq %d is unsupported "
+                               "by xen!\n", vec);
+                        break;
+                }
+                BUG_ON(irq < 0);
+
+                if (irq > 0) {
+                        /*
+                         * Mark percpu.  Without this, migrate_irqs() will
+                         * mark the interrupt for migrations and trigger it
+                         * on cpu hotplug.
+                         */
+                        desc = irq_desc + irq;
+                        desc->status |= IRQ_PER_CPU;
+                }
+        }
+
+        /* For BSP, we cache registered percpu irqs, and then re-walk
+         * them when initializing APs
+         */
+        if (!cpu && save) {
+                BUG_ON(saved_irq_cnt == MAX_LATE_IRQ);
+                saved_percpu_irqs[saved_irq_cnt].irq = vec;
+                saved_percpu_irqs[saved_irq_cnt].action = action;
+                saved_irq_cnt++;
+                if (!xen_slab_ready)
+                        late_irq_cnt++;
+        }
+}
+
+static void
+xen_register_percpu_irq(ia64_vector vec, struct irqaction *action)
+{
+        __xen_register_percpu_irq(smp_processor_id(), vec, action, 1);
+}
+
+static void
+xen_bind_early_percpu_irq(void)
+{
+        int i;
+
+        xen_slab_ready = 1;
+        /* There's no race when accessing this cached array, since only
+         * BSP will face with such step shortly
+         */
+        for (i = 0; i < late_irq_cnt; i++)
+                __xen_register_percpu_irq(smp_processor_id(),
+                                          saved_percpu_irqs[i].irq,
+                                          saved_percpu_irqs[i].action, 0);
+}
+
+/* FIXME: There's no obvious point to check whether slab is ready. So
+ * a hack is used here by utilizing a late time hook.
+ */
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int __devinit
+unbind_evtchn_callback(struct notifier_block *nfb,
+                       unsigned long action, void *hcpu)
+{
+        unsigned int cpu = (unsigned long)hcpu;
+
+        if (action == CPU_DEAD) {
+                /* Unregister evtchn.  */
+                if (per_cpu(cpep_irq, cpu) >= 0) {
+                        unbind_from_irqhandler(per_cpu(cpep_irq, cpu), NULL);
+                        per_cpu(cpep_irq, cpu) = -1;
+                }
+                if (per_cpu(cmcp_irq, cpu) >= 0) {
+                        unbind_from_irqhandler(per_cpu(cmcp_irq, cpu), NULL);
+                        per_cpu(cmcp_irq, cpu) = -1;
+                }
+                if (per_cpu(cmc_irq, cpu) >= 0) {
+                        unbind_from_irqhandler(per_cpu(cmc_irq, cpu), NULL);
+                        per_cpu(cmc_irq, cpu) = -1;
+                }
+                if (per_cpu(ipi_irq, cpu) >= 0) {
+                        unbind_from_irqhandler(per_cpu(ipi_irq, cpu), NULL);
+                        per_cpu(ipi_irq, cpu) = -1;
+                }
+                if (per_cpu(resched_irq, cpu) >= 0) {
+                        unbind_from_irqhandler(per_cpu(resched_irq, cpu),
+                                                NULL);
+                        per_cpu(resched_irq, cpu) = -1;
+                }
+                if (per_cpu(timer_irq, cpu) >= 0) {
+                        unbind_from_irqhandler(per_cpu(timer_irq, cpu), NULL);
+                        per_cpu(timer_irq, cpu) = -1;
+                }
+        }
+        return NOTIFY_OK;
+}
+
+static struct notifier_block unbind_evtchn_notifier = {
+        .notifier_call = unbind_evtchn_callback,
+        .priority = 0
+};
+#endif
+
+void xen_smp_intr_init_early(unsigned int cpu)
+{
+#ifdef CONFIG_SMP
+        unsigned int i;
+
+        for (i = 0; i < saved_irq_cnt; i++)
+                __xen_register_percpu_irq(cpu, saved_percpu_irqs[i].irq,
+                                          saved_percpu_irqs[i].action, 0);
+#endif
+}
+
+void xen_smp_intr_init(void)
+{
+#ifdef CONFIG_SMP
+        unsigned int cpu = smp_processor_id();
+        struct callback_register event = {
+                .type = CALLBACKTYPE_event,
+                .address = { .ip = (unsigned long)&xen_event_callback },
+        };
+
+        if (cpu == 0) {
+                /* Initialization was already done for boot cpu.  */
+#ifdef CONFIG_HOTPLUG_CPU
+                /* Register the notifier only once.  */
+                register_cpu_notifier(&unbind_evtchn_notifier);
+#endif
+                return;
+        }
+
+        /* This should be piggyback when setup vcpu guest context */
+        BUG_ON(HYPERVISOR_callback_op(CALLBACKOP_register, &event));
+#endif /* CONFIG_SMP */
+}
+
+void __init
+xen_irq_init(void)
+{
+        struct callback_register event = {
+                .type = CALLBACKTYPE_event,
+                .address = { .ip = (unsigned long)&xen_event_callback },
+        };
+
+        xen_init_IRQ();
+        BUG_ON(HYPERVISOR_callback_op(CALLBACKOP_register, &event));
+        late_time_init = xen_bind_early_percpu_irq;
+}
+
+void
+xen_platform_send_ipi(int cpu, int vector, int delivery_mode, int redirect)
+{
+#ifdef CONFIG_SMP
+        /* TODO: we need to call vcpu_up here */
+        if (unlikely(vector == ap_wakeup_vector)) {
+                /* XXX
+                 * This should be in __cpu_up(cpu) in ia64 smpboot.c
+                 * like x86. But don't want to modify it,
+                 * keep it untouched.
+                 */
+                xen_smp_intr_init_early(cpu);
+
+                xen_send_ipi(cpu, vector);
+                /* vcpu_prepare_and_up(cpu); */
+                return;
+        }
+#endif
+
+        switch (vector) {
+        case IA64_IPI_VECTOR:
+                xen_send_IPI_one(cpu, XEN_IPI_VECTOR);
+                break;
+        case IA64_IPI_RESCHEDULE:
+                xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
+                break;
+        case IA64_CMCP_VECTOR:
+                xen_send_IPI_one(cpu, XEN_CMCP_VECTOR);
+                break;
+        case IA64_CPEP_VECTOR:
+                xen_send_IPI_one(cpu, XEN_CPEP_VECTOR);
+                break;
+        case IA64_TIMER_VECTOR: {
+                /* this is used only once by check_sal_cache_flush()
+                   at boot time */
+                static int used = 0;
+                if (!used) {
+                        xen_send_ipi(cpu, IA64_TIMER_VECTOR);
+                        used = 1;
+                        break;
+                }
+                /* fallthrough */
+        }
+        default:
+                printk(KERN_WARNING "Unsupported IPI type 0x%x\n",
+                       vector);
+                notify_remote_via_irq(0); /* defaults to 0 irq */
+                break;
+        }
+}
+
+static void __init
+xen_register_ipi(void)
+{
+#ifdef CONFIG_SMP
+        register_percpu_irq(IA64_IPI_VECTOR, &xen_ipi_irqaction);
+        register_percpu_irq(IA64_IPI_RESCHEDULE, &xen_resched_irqaction);
+        register_percpu_irq(IA64_IPI_LOCAL_TLB_FLUSH, &xen_tlb_irqaction);
+#endif
+}
+
+static void
+xen_resend_irq(unsigned int vector)
+{
+        (void)resend_irq_on_evtchn(vector);
+}
+
+const struct pv_irq_ops xen_irq_ops __initdata = {
+        .register_ipi = xen_register_ipi,
+
+        .assign_irq_vector = xen_assign_irq_vector,
+        .free_irq_vector = xen_free_irq_vector,
+        .register_percpu_irq = xen_register_percpu_irq,
+
+        .resend_irq = xen_resend_irq,
+};