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authorMilton Miller <miltonm@bga.com>2011-05-24 20:34:18 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-05-26 13:38:59 +1000
commit2e455257d143f54b44701e947a092d513889d01c (patch)
tree3ec9c640c1bce6b2ea78accc0b0b962f97595e0c
parent3d1b5e206a4f0ce46f2aa138590738c5d8e118ac (diff)
powerpc/irq: Check desc in handle_one_irq and expand generic_handle_irq
Look up the descriptor and check that it is found in handle_one_irq before checking if we are on the irq stack, and call the handler directly using the descriptor if we are on the stack. We need check irq_to_desc finds the descriptor to avoid a NULL pointer dereference. It could have failed because the number from ppc_md.get_irq was above NR_IRQS, or various exceptional conditions with sparse irqs (eg race conditions while freeing an irq if its was not shutdown in the controller). fe12bc2c99 (genirq: Uninline and sanity check generic_handle_irq()) moved generic_handle_irq out of line to allow its use by interrupt controllers in modules. However, handle_one_irq is core arch code. It already knows the details of struct irq_desc and handling irqs in the nested irq case. This will avoid the extra stack frame to return the value we don't check. Signed-off-by: Milton Miller <miltonm@bga.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r--arch/powerpc/kernel/irq.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 0df255414836..ac4d29119f3e 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -295,17 +295,20 @@ static inline void handle_one_irq(unsigned int irq)
unsigned long saved_sp_limit;
struct irq_desc *desc;
+ desc = irq_to_desc(irq);
+ if (!desc)
+ return;
+
/* Switch to the irq stack to handle this */
curtp = current_thread_info();
irqtp = hardirq_ctx[smp_processor_id()];
if (curtp == irqtp) {
/* We're already on the irq stack, just handle it */
- generic_handle_irq(irq);
+ desc->handle_irq(irq, desc);
return;
}
- desc = irq_to_desc(irq);
saved_sp_limit = current->thread.ksp_limit;
irqtp->task = curtp->task;