powerpc/irqdomain: Fix broken NR_IRQ references

The switch from using irq_map to irq_alloc_desc*() for managing irq
number allocations introduced new bugs in some of the powerpc
interrupt code.  Several functions rely on the value of NR_IRQS to
determine the maximum irq number that could get allocated.  However,
with sparse_irq and using irq_alloc_desc*() the maximum possible irq
number is now specified with 'nr_irqs' which may be a number larger
than NR_IRQS.  This has caused breakage on powermac when
CONFIG_NR_IRQS is set to 32.

This patch removes most of the direct references to NR_IRQS in the
powerpc code and replaces them with either a nr_irqs reference or by
using the common for_each_irq_desc() macro.  The powerpc-specific
for_each_irq() macro is removed at the same time.

Also, the Cell axon_msi driver is refactored to remove the global
build assumption on the size of NR_IRQS and instead add a limit to the
maximum irq number when calling irq_domain_add_nomap().

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 3 insertions, 5 deletions

diff --git a/arch/powerpc/platforms/cell/axon_msi.c b/arch/powerpc/platforms/cell/axon_msi.c
index d09f3e8e6867..85825b5401e5 100644
--- a/arch/powerpc/platforms/cell/axon_msi.c
+++ b/arch/powerpc/platforms/cell/axon_msi.c
@@ -114,7 +114,7 @@ static void axon_msi_cascade(unsigned int irq, struct irq_desc *desc)
                 pr_devel("axon_msi: woff %x roff %x msi %x\n",
                           write_offset, msic->read_offset, msi);
 
-                if (msi < NR_IRQS && irq_get_chip_data(msi) == msic) {
+                if (msi < nr_irqs && irq_get_chip_data(msi) == msic) {
                         generic_handle_irq(msi);
                         msic->fifo_virt[idx] = cpu_to_le32(0xffffffff);
                 } else {
@@ -276,9 +276,6 @@ static int axon_msi_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
         if (rc)
                 return rc;
 
-        /* We rely on being able to stash a virq in a u16 */
-        BUILD_BUG_ON(NR_IRQS > 65536);
-
         list_for_each_entry(entry, &dev->msi_list, list) {
                 virq = irq_create_direct_mapping(msic->irq_domain);
                 if (virq == NO_IRQ) {
@@ -392,7 +389,8 @@ static int axon_msi_probe(struct platform_device *device)
         }
         memset(msic->fifo_virt, 0xff, MSIC_FIFO_SIZE_BYTES);
 
-        msic->irq_domain = irq_domain_add_nomap(dn, 0, &msic_host_ops, msic);
+        /* We rely on being able to stash a virq in a u16, so limit irqs to < 65536 */
+        msic->irq_domain = irq_domain_add_nomap(dn, 65536, &msic_host_ops, msic);
         if (!msic->irq_domain) {
                 printk(KERN_ERR "axon_msi: couldn't allocate irq_domain for %s\n",
                        dn->full_name);