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>

2 files changed, 3 insertions, 10 deletions

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 5ec1b2354ca6..43eb74fcedde 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -330,14 +330,10 @@ void migrate_irqs(void)
 
         alloc_cpumask_var(&mask, GFP_KERNEL);
 
-        for_each_irq(irq) {
+        for_each_irq_desc(irq, desc) {
                 struct irq_data *data;
                 struct irq_chip *chip;
 
-                desc = irq_to_desc(irq);
-                if (!desc)
-                        continue;
-
                 data = irq_desc_get_irq_data(desc);
                 if (irqd_is_per_cpu(data))
                         continue;
diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index c957b1202bdc..5df777794403 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -23,14 +23,11 @@
 
 void machine_kexec_mask_interrupts(void) {
         unsigned int i;
+        struct irq_desc *desc;
 
-        for_each_irq(i) {
-                struct irq_desc *desc = irq_to_desc(i);
+        for_each_irq_desc(i, desc) {
                 struct irq_chip *chip;
 
-                if (!desc)
-                        continue;
-
                 chip = irq_desc_get_chip(desc);
                 if (!chip)
                         continue;