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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>
This commit is contained in:
parent
3d1b5e206a
commit
2e455257d1
@ -295,17 +295,20 @@ static inline void handle_one_irq(unsigned int irq)
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unsigned long saved_sp_limit;
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struct irq_desc *desc;
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desc = irq_to_desc(irq);
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if (!desc)
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return;
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/* Switch to the irq stack to handle this */
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curtp = current_thread_info();
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irqtp = hardirq_ctx[smp_processor_id()];
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if (curtp == irqtp) {
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/* We're already on the irq stack, just handle it */
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generic_handle_irq(irq);
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desc->handle_irq(irq, desc);
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return;
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}
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desc = irq_to_desc(irq);
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saved_sp_limit = current->thread.ksp_limit;
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irqtp->task = curtp->task;
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