sparc64: sparse irq

This patch attempts to do a few things. The highlights are: 1) enable
SPARSE_IRQ unconditionally, 2) kills off !SPARSE_IRQ code 3) allocates
ivector_table at boot time and 4) default to cookie only VIRQ mechanism
for supported firmware. The first firmware with cookie only support for
me appears on T5. You can optionally force the HV firmware to not cookie
only mode which is the sysino support.

The sysino is a deprecated HV mechanism according to the most recent
SPARC Virtual Machine Specification. HV_GRP_INTR is what controls the
cookie/sysino firmware versioning.

The history of this interface is:

1) Major version 1.0 only supported sysino based interrupt interfaces.

2) Major version 2.0 added cookie based VIRQs, however due to the fact
   that OSs were using the VIRQs without negoatiating major version
   2.0 (Linux and Solaris are both guilty), the VIRQs calls were
   allowed even with major version 1.0

   To complicate things even further, the VIRQ interfaces were only
   actually hooked up in the hypervisor for LDC interrupt sources.
   VIRQ calls on other device types would result in HV_EINVAL errors.

   So effectively, major version 2.0 is unusable.

3) Major version 3.0 was created to signal use of VIRQs and the fact
   that the hypervisor has these calls hooked up for all interrupt
   sources, not just those for LDC devices.

A new boot option is provided should cookie only HV support have issues.
hvirq - this is the version for HV_GRP_INTR. This is related to HV API
versioning.  The code attempts major=3 first by default. The option can
be used to override this default.

I've tested with SPARSE_IRQ on T5-8, M7-4 and T4-X and Jalap?no.

Signed-off-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 338 insertions, 169 deletions

diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c
index 666193f4e8bb..4033c23bdfa6 100644
--- a/arch/sparc/kernel/irq_64.c
+++ b/arch/sparc/kernel/irq_64.c
@@ -47,8 +47,6 @@
 #include "cpumap.h"
 #include "kstack.h"
 
-#define NUM_IVECS	(IMAP_INR + 1)
-
 struct ino_bucket *ivector_table;
 unsigned long ivector_table_pa;
 
@@ -107,55 +105,196 @@ static void bucket_set_irq(unsigned long bucket_pa, unsigned int irq)
 
 #define irq_work_pa(__cpu)	&(trap_block[(__cpu)].irq_worklist_pa)
 
-static struct {
-	unsigned int dev_handle;
-	unsigned int dev_ino;
-	unsigned int in_use;
-} irq_table[NR_IRQS];
-static DEFINE_SPINLOCK(irq_alloc_lock);
+static unsigned long hvirq_major __initdata;
+static int __init early_hvirq_major(char *p)
+{
+	int rc = kstrtoul(p, 10, &hvirq_major);
+
+	return rc;
+}
+early_param("hvirq", early_hvirq_major);
+
+static int hv_irq_version;
+
+/* Major version 2.0 of HV_GRP_INTR added support for the VIRQ cookie
+ * based interfaces, but:
+ *
+ * 1) Several OSs, Solaris and Linux included, use them even when only
+ *    negotiating version 1.0 (or failing to negotiate at all).  So the
+ *    hypervisor has a workaround that provides the VIRQ interfaces even
+ *    when only verion 1.0 of the API is in use.
+ *
+ * 2) Second, and more importantly, with major version 2.0 these VIRQ
+ *    interfaces only were actually hooked up for LDC interrupts, even
+ *    though the Hypervisor specification clearly stated:
+ *
+ *	The new interrupt API functions will be available to a guest
+ *	when it negotiates version 2.0 in the interrupt API group 0x2. When
+ *	a guest negotiates version 2.0, all interrupt sources will only
+ *	support using the cookie interface, and any attempt to use the
+ *	version 1.0 interrupt APIs numbered 0xa0 to 0xa6 will result in the
+ *	ENOTSUPPORTED error being returned.
+ *
+ *   with an emphasis on "all interrupt sources".
+ *
+ * To correct this, major version 3.0 was created which does actually
+ * support VIRQs for all interrupt sources (not just LDC devices).  So
+ * if we want to move completely over the cookie based VIRQs we must
+ * negotiate major version 3.0 or later of HV_GRP_INTR.
+ */
+static bool sun4v_cookie_only_virqs(void)
+{
+	if (hv_irq_version >= 3)
+		return true;
+	return false;
+}
 
-unsigned char irq_alloc(unsigned int dev_handle, unsigned int dev_ino)
+static void __init irq_init_hv(void)
 {
-	unsigned long flags;
-	unsigned char ent;
+	unsigned long hv_error, major, minor = 0;
+
+	if (tlb_type != hypervisor)
+		return;
 
-	BUILD_BUG_ON(NR_IRQS >= 256);
+	if (hvirq_major)
+		major = hvirq_major;
+	else
+		major = 3;
 
-	spin_lock_irqsave(&irq_alloc_lock, flags);
+	hv_error = sun4v_hvapi_register(HV_GRP_INTR, major, &minor);
+	if (!hv_error)
+		hv_irq_version = major;
+	else
+		hv_irq_version = 1;
 
-	for (ent = 1; ent < NR_IRQS; ent++) {
-		if (!irq_table[ent].in_use)
+	pr_info("SUN4V: Using IRQ API major %d, cookie only virqs %s\n",
+		hv_irq_version,
+		sun4v_cookie_only_virqs() ? "enabled" : "disabled");
+}
+
+/* This function is for the timer interrupt.*/
+int __init arch_probe_nr_irqs(void)
+{
+	return 1;
+}
+
+#define DEFAULT_NUM_IVECS	(0xfffU)
+static unsigned int nr_ivec = DEFAULT_NUM_IVECS;
+#define NUM_IVECS (nr_ivec)
+
+static unsigned int __init size_nr_ivec(void)
+{
+	if (tlb_type == hypervisor) {
+		switch (sun4v_chip_type) {
+		/* Athena's devhandle|devino is large.*/
+		case SUN4V_CHIP_SPARC64X:
+			nr_ivec = 0xffff;
 			break;
+		}
 	}
-	if (ent >= NR_IRQS) {
-		printk(KERN_ERR "IRQ: Out of virtual IRQs.\n");
-		ent = 0;
-	} else {
-		irq_table[ent].dev_handle = dev_handle;
-		irq_table[ent].dev_ino = dev_ino;
-		irq_table[ent].in_use = 1;
-	}
+	return nr_ivec;
+}
+
+struct irq_handler_data {
+	union {
+		struct {
+			unsigned int dev_handle;
+			unsigned int dev_ino;
+		};
+		unsigned long sysino;
+	};
+	struct ino_bucket bucket;
+	unsigned long	iclr;
+	unsigned long	imap;
+};
+
+static inline unsigned int irq_data_to_handle(struct irq_data *data)
+{
+	struct irq_handler_data *ihd = data->handler_data;
+
+	return ihd->dev_handle;
+}
+
+static inline unsigned int irq_data_to_ino(struct irq_data *data)
+{
+	struct irq_handler_data *ihd = data->handler_data;
 
-	spin_unlock_irqrestore(&irq_alloc_lock, flags);
+	return ihd->dev_ino;
+}
+
+static inline unsigned long irq_data_to_sysino(struct irq_data *data)
+{
+	struct irq_handler_data *ihd = data->handler_data;
 
-	return ent;
+	return ihd->sysino;
 }
 
-#ifdef CONFIG_PCI_MSI
 void irq_free(unsigned int irq)
 {
-	unsigned long flags;
+	void *data = irq_get_handler_data(irq);
 
-	if (irq >= NR_IRQS)
-		return;
+	kfree(data);
+	irq_set_handler_data(irq, NULL);
+	irq_free_descs(irq, 1);
+}
 
-	spin_lock_irqsave(&irq_alloc_lock, flags);
+unsigned int irq_alloc(unsigned int dev_handle, unsigned int dev_ino)
+{
+	int irq;
 
-	irq_table[irq].in_use = 0;
+	irq = __irq_alloc_descs(-1, 1, 1, numa_node_id(), NULL);
+	if (irq <= 0)
+		goto out;
 
-	spin_unlock_irqrestore(&irq_alloc_lock, flags);
+	return irq;
+out:
+	return 0;
+}
+
+static unsigned int cookie_exists(u32 devhandle, unsigned int devino)
+{
+	unsigned long hv_err, cookie;
+	struct ino_bucket *bucket;
+	unsigned int irq = 0U;
+
+	hv_err = sun4v_vintr_get_cookie(devhandle, devino, &cookie);
+	if (hv_err) {
+		pr_err("HV get cookie failed hv_err = %ld\n", hv_err);
+		goto out;
+	}
+
+	if (cookie & ((1UL << 63UL))) {
+		cookie = ~cookie;
+		bucket = (struct ino_bucket *) __va(cookie);
+		irq = bucket->__irq;
+	}
+out:
+	return irq;
+}
+
+static unsigned int sysino_exists(u32 devhandle, unsigned int devino)
+{
+	unsigned long sysino = sun4v_devino_to_sysino(devhandle, devino);
+	struct ino_bucket *bucket;
+	unsigned int irq;
+
+	bucket = &ivector_table[sysino];
+	irq = bucket_get_irq(__pa(bucket));
+
+	return irq;
+}
+
+void ack_bad_irq(unsigned int irq)
+{
+	pr_crit("BAD IRQ ack %d\n", irq);
+}
+
+void irq_install_pre_handler(int irq,
+			     void (*func)(unsigned int, void *, void *),
+			     void *arg1, void *arg2)
+{
+	pr_warn("IRQ pre handler NOT supported.\n");
 }
-#endif
 
 /*
  * /proc/interrupts printing:
@@ -206,15 +345,6 @@ static unsigned int sun4u_compute_tid(unsigned long imap, unsigned long cpuid)
 	return tid;
 }
 
-struct irq_handler_data {
-	unsigned long	iclr;
-	unsigned long	imap;
-
-	void		(*pre_handler)(unsigned int, void *, void *);
-	void		*arg1;
-	void		*arg2;
-};
-
 #ifdef CONFIG_SMP
 static int irq_choose_cpu(unsigned int irq, const struct cpumask *affinity)
 {
@@ -316,8 +446,8 @@ static void sun4u_irq_eoi(struct irq_data *data)
 
 static void sun4v_irq_enable(struct irq_data *data)
 {
-	unsigned int ino = irq_table[data->irq].dev_ino;
 	unsigned long cpuid = irq_choose_cpu(data->irq, data->affinity);
+	unsigned int ino = irq_data_to_sysino(data);
 	int err;
 
 	err = sun4v_intr_settarget(ino, cpuid);
@@ -337,8 +467,8 @@ static void sun4v_irq_enable(struct irq_data *data)
 static int sun4v_set_affinity(struct irq_data *data,
 			       const struct cpumask *mask, bool force)
 {
-	unsigned int ino = irq_table[data->irq].dev_ino;
 	unsigned long cpuid = irq_choose_cpu(data->irq, mask);
+	unsigned int ino = irq_data_to_sysino(data);
 	int err;
 
 	err = sun4v_intr_settarget(ino, cpuid);
@@ -351,7 +481,7 @@ static int sun4v_set_affinity(struct irq_data *data,
 
 static void sun4v_irq_disable(struct irq_data *data)
 {
-	unsigned int ino = irq_table[data->irq].dev_ino;
+	unsigned int ino = irq_data_to_sysino(data);
 	int err;
 
 	err = sun4v_intr_setenabled(ino, HV_INTR_DISABLED);
@@ -362,7 +492,7 @@ static void sun4v_irq_disable(struct irq_data *data)
 
 static void sun4v_irq_eoi(struct irq_data *data)
 {
-	unsigned int ino = irq_table[data->irq].dev_ino;
+	unsigned int ino = irq_data_to_sysino(data);
 	int err;
 
 	err = sun4v_intr_setstate(ino, HV_INTR_STATE_IDLE);
@@ -373,14 +503,13 @@ static void sun4v_irq_eoi(struct irq_data *data)
 
 static void sun4v_virq_enable(struct irq_data *data)
 {
-	unsigned long cpuid, dev_handle, dev_ino;
+	unsigned long dev_handle = irq_data_to_handle(data);
+	unsigned long dev_ino = irq_data_to_ino(data);
+	unsigned long cpuid;
 	int err;
 
 	cpuid = irq_choose_cpu(data->irq, data->affinity);
 
-	dev_handle = irq_table[data->irq].dev_handle;
-	dev_ino = irq_table[data->irq].dev_ino;
-
 	err = sun4v_vintr_set_target(dev_handle, dev_ino, cpuid);
 	if (err != HV_EOK)
 		printk(KERN_ERR "sun4v_vintr_set_target(%lx,%lx,%lu): "
@@ -403,14 +532,13 @@ static void sun4v_virq_enable(struct irq_data *data)
 static int sun4v_virt_set_affinity(struct irq_data *data,
 				    const struct cpumask *mask, bool force)
 {
-	unsigned long cpuid, dev_handle, dev_ino;
+	unsigned long dev_handle = irq_data_to_handle(data);
+	unsigned long dev_ino = irq_data_to_ino(data);
+	unsigned long cpuid;
 	int err;
 
 	cpuid = irq_choose_cpu(data->irq, mask);
 
-	dev_handle = irq_table[data->irq].dev_handle;
-	dev_ino = irq_table[data->irq].dev_ino;
-
 	err = sun4v_vintr_set_target(dev_handle, dev_ino, cpuid);
 	if (err != HV_EOK)
 		printk(KERN_ERR "sun4v_vintr_set_target(%lx,%lx,%lu): "
@@ -422,11 +550,10 @@ static int sun4v_virt_set_affinity(struct irq_data *data,
 
 static void sun4v_virq_disable(struct irq_data *data)
 {
-	unsigned long dev_handle, dev_ino;
+	unsigned long dev_handle = irq_data_to_handle(data);
+	unsigned long dev_ino = irq_data_to_ino(data);
 	int err;
 
-	dev_handle = irq_table[data->irq].dev_handle;
-	dev_ino = irq_table[data->irq].dev_ino;
 
 	err = sun4v_vintr_set_valid(dev_handle, dev_ino,
 				    HV_INTR_DISABLED);
@@ -438,12 +565,10 @@ static void sun4v_virq_disable(struct irq_data *data)
 
 static void sun4v_virq_eoi(struct irq_data *data)
 {
-	unsigned long dev_handle, dev_ino;
+	unsigned long dev_handle = irq_data_to_handle(data);
+	unsigned long dev_ino = irq_data_to_ino(data);
 	int err;
 
-	dev_handle = irq_table[data->irq].dev_handle;
-	dev_ino = irq_table[data->irq].dev_ino;
-
 	err = sun4v_vintr_set_state(dev_handle, dev_ino,
 				    HV_INTR_STATE_IDLE);
 	if (err != HV_EOK)
@@ -479,31 +604,10 @@ static struct irq_chip sun4v_virq = {
 	.flags			= IRQCHIP_EOI_IF_HANDLED,
 };
 
-static void pre_flow_handler(struct irq_data *d)
-{
-	struct irq_handler_data *handler_data = irq_data_get_irq_handler_data(d);
-	unsigned int ino = irq_table[d->irq].dev_ino;
-
-	handler_data->pre_handler(ino, handler_data->arg1, handler_data->arg2);
-}
-
-void irq_install_pre_handler(int irq,
-			     void (*func)(unsigned int, void *, void *),
-			     void *arg1, void *arg2)
-{
-	struct irq_handler_data *handler_data = irq_get_handler_data(irq);
-
-	handler_data->pre_handler = func;
-	handler_data->arg1 = arg1;
-	handler_data->arg2 = arg2;
-
-	__irq_set_preflow_handler(irq, pre_flow_handler);
-}
-
 unsigned int build_irq(int inofixup, unsigned long iclr, unsigned long imap)
 {
-	struct ino_bucket *bucket;
 	struct irq_handler_data *handler_data;
+	struct ino_bucket *bucket;
 	unsigned int irq;
 	int ino;
 
@@ -537,119 +641,166 @@ out:
 	return irq;
 }
 
-static unsigned int sun4v_build_common(unsigned long sysino,
-				       struct irq_chip *chip)
+static unsigned int sun4v_build_common(u32 devhandle, unsigned int devino,
+		void (*handler_data_init)(struct irq_handler_data *data,
+		u32 devhandle, unsigned int devino),
+		struct irq_chip *chip)
 {
-	struct ino_bucket *bucket;
-	struct irq_handler_data *handler_data;
+	struct irq_handler_data *data;
 	unsigned int irq;
 
-	BUG_ON(tlb_type != hypervisor);
+	irq = irq_alloc(devhandle, devino);
+	if (!irq)
+		goto out;
 
-	bucket = &ivector_table[sysino];
-	irq = bucket_get_irq(__pa(bucket));
-	if (!irq) {
-		irq = irq_alloc(0, sysino);
-		bucket_set_irq(__pa(bucket), irq);
-		irq_set_chip_and_handler_name(irq, chip, handle_fasteoi_irq,
-					      "IVEC");
+	data = kzalloc(sizeof(struct irq_handler_data), GFP_ATOMIC);
+	if (unlikely(!data)) {
+		pr_err("IRQ handler data allocation failed.\n");
+		irq_free(irq);
+		irq = 0;
+		goto out;
 	}
 
-	handler_data = irq_get_handler_data(irq);
-	if (unlikely(handler_data))
-		goto out;
+	irq_set_handler_data(irq, data);
+	handler_data_init(data, devhandle, devino);
+	irq_set_chip_and_handler_name(irq, chip, handle_fasteoi_irq, "IVEC");
+	data->imap = ~0UL;
+	data->iclr = ~0UL;
+out:
+	return irq;
+}
 
-	handler_data = kzalloc(sizeof(struct irq_handler_data), GFP_ATOMIC);
-	if (unlikely(!handler_data)) {
-		prom_printf("IRQ: kzalloc(irq_handler_data) failed.\n");
-		prom_halt();
-	}
-	irq_set_handler_data(irq, handler_data);
+static unsigned long cookie_assign(unsigned int irq, u32 devhandle,
+		unsigned int devino)
+{
+	struct irq_handler_data *ihd = irq_get_handler_data(irq);
+	unsigned long hv_error, cookie;
 
-	/* Catch accidental accesses to these things.  IMAP/ICLR handling
-	 * is done by hypervisor calls on sun4v platforms, not by direct
-	 * register accesses.
+	/* handler_irq needs to find the irq. cookie is seen signed in
+	 * sun4v_dev_mondo and treated as a non ivector_table delivery.
 	 */
-	handler_data->imap = ~0UL;
-	handler_data->iclr = ~0UL;
+	ihd->bucket.__irq = irq;
+	cookie = ~__pa(&ihd->bucket);
 
-out:
-	return irq;
+	hv_error = sun4v_vintr_set_cookie(devhandle, devino, cookie);
+	if (hv_error)
+		pr_err("HV vintr set cookie failed = %ld\n", hv_error);
+
+	return hv_error;
 }
 
-unsigned int sun4v_build_irq(u32 devhandle, unsigned int devino)
+static void cookie_handler_data(struct irq_handler_data *data,
+				u32 devhandle, unsigned int devino)
 {
-	unsigned long sysino = sun4v_devino_to_sysino(devhandle, devino);
+	data->dev_handle = devhandle;
+	data->dev_ino = devino;
+}
 
-	return sun4v_build_common(sysino, &sun4v_irq);
+static unsigned int cookie_build_irq(u32 devhandle, unsigned int devino,
+				     struct irq_chip *chip)
+{
+	unsigned long hv_error;
+	unsigned int irq;
+
+	irq = sun4v_build_common(devhandle, devino, cookie_handler_data, chip);
+
+	hv_error = cookie_assign(irq, devhandle, devino);
+	if (hv_error) {
+		irq_free(irq);
+		irq = 0;
+	}
+
+	return irq;
 }
 
-unsigned int sun4v_build_virq(u32 devhandle, unsigned int devino)
+static unsigned int sun4v_build_cookie(u32 devhandle, unsigned int devino)
 {
-	struct irq_handler_data *handler_data;
-	unsigned long hv_err, cookie;
-	struct ino_bucket *bucket;
 	unsigned int irq;
 
-	bucket = kzalloc(sizeof(struct ino_bucket), GFP_ATOMIC);
-	if (unlikely(!bucket))
-		return 0;
+	irq = cookie_exists(devhandle, devino);
+	if (irq)
+		goto out;
 
-	/* The only reference we store to the IRQ bucket is
-	 * by physical address which kmemleak can't see, tell
-	 * it that this object explicitly is not a leak and
-	 * should be scanned.
-	 */
-	kmemleak_not_leak(bucket);
+	irq = cookie_build_irq(devhandle, devino, &sun4v_virq);
 
-	__flush_dcache_range((unsigned long) bucket,
-			     ((unsigned long) bucket +
-			      sizeof(struct ino_bucket)));
+out:
+	return irq;
+}
 
-	irq = irq_alloc(devhandle, devino);
+static void sysino_set_bucket(unsigned int irq)
+{
+	struct irq_handler_data *ihd = irq_get_handler_data(irq);
+	struct ino_bucket *bucket;
+	unsigned long sysino;
+
+	sysino = sun4v_devino_to_sysino(ihd->dev_handle, ihd->dev_ino);
+	BUG_ON(sysino >= nr_ivec);
+	bucket = &ivector_table[sysino];
 	bucket_set_irq(__pa(bucket), irq);
+}
 
-	irq_set_chip_and_handler_name(irq, &sun4v_virq, handle_fasteoi_irq,
-				      "IVEC");
+static void sysino_handler_data(struct irq_handler_data *data,
+				u32 devhandle, unsigned int devino)
+{
+	unsigned long sysino;
 
-	handler_data = kzalloc(sizeof(struct irq_handler_data), GFP_ATOMIC);
-	if (unlikely(!handler_data))
-		return 0;
+	sysino = sun4v_devino_to_sysino(devhandle, devino);
+	data->sysino = sysino;
+}
 
-	/* In order to make the LDC channel startup sequence easier,
-	 * especially wrt. locking, we do not let request_irq() enable
-	 * the interrupt.
-	 */
-	irq_set_status_flags(irq, IRQ_NOAUTOEN);
-	irq_set_handler_data(irq, handler_data);
+static unsigned int sysino_build_irq(u32 devhandle, unsigned int devino,
+				     struct irq_chip *chip)
+{
+	unsigned int irq;
 
-	/* Catch accidental accesses to these things.  IMAP/ICLR handling
-	 * is done by hypervisor calls on sun4v platforms, not by direct
-	 * register accesses.
-	 */
-	handler_data->imap = ~0UL;
-	handler_data->iclr = ~0UL;
+	irq = sun4v_build_common(devhandle, devino, sysino_handler_data, chip);
+	if (!irq)
+		goto out;
 
-	cookie = ~__pa(bucket);
-	hv_err = sun4v_vintr_set_cookie(devhandle, devino, cookie);
-	if (hv_err) {
-		prom_printf("IRQ: Fatal, cannot set cookie for [%x:%x] "
-			    "err=%lu\n", devhandle, devino, hv_err);
-		prom_halt();
-	}
+	sysino_set_bucket(irq);
+out:
+	return irq;
+}
 
+static int sun4v_build_sysino(u32 devhandle, unsigned int devino)
+{
+	int irq;
+
+	irq = sysino_exists(devhandle, devino);
+	if (irq)
+		goto out;
+
+	irq = sysino_build_irq(devhandle, devino, &sun4v_irq);
+out:
 	return irq;
 }
 
-void ack_bad_irq(unsigned int irq)
+unsigned int sun4v_build_irq(u32 devhandle, unsigned int devino)
 {
-	unsigned int ino = irq_table[irq].dev_ino;
+	unsigned int irq;
 
-	if (!ino)
-		ino = 0xdeadbeef;
+	if (sun4v_cookie_only_virqs())
+		irq = sun4v_build_cookie(devhandle, devino);
+	else
+		irq = sun4v_build_sysino(devhandle, devino);
 
-	printk(KERN_CRIT "Unexpected IRQ from ino[%x] irq[%u]\n",
-	       ino, irq);
+	return irq;
+}
+
+unsigned int sun4v_build_virq(u32 devhandle, unsigned int devino)
+{
+	int irq;
+
+	irq = cookie_build_irq(devhandle, devino, &sun4v_virq);
+	if (!irq)
+		goto out;
+
+	/* This is borrowed from the original function.
+	 */
+	irq_set_status_flags(irq, IRQ_NOAUTOEN);
+
+out:
+	return irq;
 }
 
 void *hardirq_stack[NR_CPUS];
@@ -720,9 +871,12 @@ void fixup_irqs(void)
 
 	for (irq = 0; irq < NR_IRQS; irq++) {
 		struct irq_desc *desc = irq_to_desc(irq);
-		struct irq_data *data = irq_desc_get_irq_data(desc);
+		struct irq_data *data;
 		unsigned long flags;
 
+		if (!desc)
+			continue;
+		data = irq_desc_get_irq_data(desc);
 		raw_spin_lock_irqsave(&desc->lock, flags);
 		if (desc->action && !irqd_is_per_cpu(data)) {
 			if (data->chip->irq_set_affinity)
@@ -922,16 +1076,22 @@ static struct irqaction timer_irq_action = {
 	.name = "timer",
 };
 
-/* Only invoked on boot processor. */
-void __init init_IRQ(void)
+static void __init irq_ivector_init(void)
 {
-	unsigned long size;
+	unsigned long size, order;
+	unsigned int ivecs;
 
-	map_prom_timers();
-	kill_prom_timer();
+	/* If we are doing cookie only VIRQs then we do not need the ivector
+	 * table to process interrupts.
+	 */
+	if (sun4v_cookie_only_virqs())
+		return;
 
-	size = sizeof(struct ino_bucket) * NUM_IVECS;
-	ivector_table = kzalloc(size, GFP_KERNEL);
+	ivecs = size_nr_ivec();
+	size = sizeof(struct ino_bucket) * ivecs;
+	order = get_order(size);
+	ivector_table = (struct ino_bucket *)
+		__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
 	if (!ivector_table) {
 		prom_printf("Fatal error, cannot allocate ivector_table\n");
 		prom_halt();
@@ -940,6 +1100,15 @@ void __init init_IRQ(void)
 			     ((unsigned long) ivector_table) + size);
 
 	ivector_table_pa = __pa(ivector_table);
+}
+
+/* Only invoked on boot processor.*/
+void __init init_IRQ(void)
+{
+	irq_init_hv();
+	irq_ivector_init();
+	map_prom_timers();
+	kill_prom_timer();
 
 	if (tlb_type == hypervisor)
 		sun4v_init_mondo_queues();