Defining CONFIG_SPARSE_IRQ enables generic code that gets rid of the
static irq_desc array, and replaces it with an array of pointers to
irq_descs.
It also allows node local allocation of irq_descs, however we
currently don't have the information available to do that, so we just
allocate them on all on node 0.
Signed-off-by: Michael Ellerman <mich...@ellerman.id.au>
---
arch/powerpc/Kconfig | 13 ++++++++++++
arch/powerpc/include/asm/irq.h | 3 ++
arch/powerpc/kernel/irq.c | 40 ++++++++++++++++++++++++++++++++------
arch/powerpc/kernel/ppc_ksyms.c | 1 -
arch/powerpc/kernel/setup_64.c | 5 ----
5 files changed, 49 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 2230e75..825d889 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -388,6 +388,19 @@ config IRQ_ALL_CPUS
CPU. Generally saying Y is safe, although some problems have been
reported with SMP Power Macintoshes with this option enabled.
+config SPARSE_IRQ
+ bool "Support sparse irq numbering"
+ default y
+ help
+ This enables support for sparse irqs. This is useful for distro
+ kernels that want to define a high CONFIG_NR_CPUS value but still
+ want to have low kernel memory footprint on smaller machines.
+
+ ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
+ out the irq_desc[] array in a more NUMA-friendly way. )
+
+ If you don't know what to do here, say Y.
+
config NUMA
bool "NUMA support"
depends on PPC64
diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
index 03dc28c..c85a32f 100644
--- a/arch/powerpc/include/asm/irq.h
+++ b/arch/powerpc/include/asm/irq.h
@@ -38,6 +38,9 @@ extern atomic_t ppc_n_lost_interrupts;
/* Number of irqs reserved for the legacy controller */
#define NUM_ISA_INTERRUPTS 16
+/* Same thing, used by the generic IRQ code */
+#define NR_IRQS_LEGACY NUM_ISA_INTERRUPTS
+
/* This type is the placeholder for a hardware interrupt number. It has to
* be big enough to enclose whatever representation is used by a given
* platform.
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 63e27d5..eba5392 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -85,7 +85,10 @@ extern int tau_interrupts(int);
#endif /* CONFIG_PPC32 */
#ifdef CONFIG_PPC64
+
+#ifndef CONFIG_SPARSE_IRQ
EXPORT_SYMBOL(irq_desc);
+#endif
int distribute_irqs = 1;
@@ -613,8 +616,16 @@ void irq_set_virq_count(unsigned int count)
static int irq_setup_virq(struct irq_host *host, unsigned int virq,
irq_hw_number_t hwirq)
{
+ struct irq_desc *desc;
+
+ desc = irq_to_desc_alloc_node(virq, 0);
+ if (!desc) {
+ pr_debug("irq: -> allocating desc failed\n");
+ goto error;
+ }
+
/* Clear IRQ_NOREQUEST flag */
- irq_to_desc(virq)->status &= ~IRQ_NOREQUEST;
+ desc->status &= ~IRQ_NOREQUEST;
/* map it */
smp_wmb();
@@ -623,11 +634,14 @@ static int irq_setup_virq(struct irq_host *host, unsigned
int virq,
if (host->ops->map(host, virq, hwirq)) {
pr_debug("irq: -> mapping failed, freeing\n");
- irq_free_virt(virq, 1);
- return -1;
+ goto error;
}
return 0;
+
+error:
+ irq_free_virt(virq, 1);
+ return -1;
}
unsigned int irq_create_direct_mapping(struct irq_host *host)
@@ -1008,12 +1022,24 @@ void irq_free_virt(unsigned int virq, unsigned int
count)
spin_unlock_irqrestore(&irq_big_lock, flags);
}
-void irq_early_init(void)
+int arch_early_irq_init(void)
{
- unsigned int i;
+ struct irq_desc *desc;
+ int i;
- for (i = 0; i < NR_IRQS; i++)
- irq_to_desc(i)->status |= IRQ_NOREQUEST;
+ for (i = 0; i < NR_IRQS; i++) {
+ desc = irq_to_desc(i);
+ if (desc)
+ desc->status |= IRQ_NOREQUEST;
+ }
+
+ return 0;
+}
+
+int arch_init_chip_data(struct irq_desc *desc, int node)
+{
+ desc->status |= IRQ_NOREQUEST;
+ return 0;
}
/* We need to create the radix trees late */
diff --git a/arch/powerpc/kernel/ppc_ksyms.c b/arch/powerpc/kernel/ppc_ksyms.c
index c8b27bb..07115d6 100644
--- a/arch/powerpc/kernel/ppc_ksyms.c
+++ b/arch/powerpc/kernel/ppc_ksyms.c
@@ -162,7 +162,6 @@ EXPORT_SYMBOL(screen_info);
#ifdef CONFIG_PPC32
EXPORT_SYMBOL(timer_interrupt);
-EXPORT_SYMBOL(irq_desc);
EXPORT_SYMBOL(tb_ticks_per_jiffy);
EXPORT_SYMBOL(cacheable_memcpy);
EXPORT_SYMBOL(cacheable_memzero);
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 797ea95..8e5ec92 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -357,11 +357,6 @@ void __init setup_system(void)
*/
initialize_cache_info();
- /*
- * Initialize irq remapping subsystem
- */
- irq_early_init();
-
#ifdef CONFIG_PPC_RTAS
/*
* Initialize RTAS if available
--
1.6.2.1
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