From: Noam Camus <no...@ezchip.com>
Working with NPS400 we noticed that there is a possibility of L1
interrupt nesting that may run out kernel stack.
The scenario include serving invoke_softirqs() from irq_exit()
and once local_irq_enable() called can hit another one before we
managed to restore last one and pop some place from kernel stack.
Serving softirqs at dedicated kernel thread may mitigate this.
We see that many architectures, including x86, behave like this.
Note 1: All interrupts which must be non threaded
should be marked IRQF_NO_THREAD.
Note 2: using kernel param "threadirqs" is needed to actually
turn this on. This configuration is only a preperation.
Signed-off-by: Noam Camus <no...@ezchip.com>
---
arch/arc/Kconfig | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 92c9128..dc1df6f 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -33,6 +33,7 @@ config ARC
select HAVE_OPROFILE
select HAVE_PERF_EVENTS
select HANDLE_DOMAIN_IRQ
+ select IRQ_FORCED_THREADING
select IRQ_DOMAIN
select MODULES_USE_ELF_RELA
select NO_BOOTMEM
--
1.7.1
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