powerpc: check_and_cede_processor() never cedes
Commit f948501b36c6 ("Make hard_irq_disable() actually hard-disable
interrupts") caused check_and_cede_processor to stop working.
->irq_happened will never be zero right after a hard_irq_disable
so the compiler removes the call to cede_processor completely.
The bug was introduced back in the lazy interrupt handling rework
of 3.4 but was hidden until recently because hard_irq_disable did
nothing.
This issue will eventually appear in 3.4 stable since the
hard_irq_disable fix is marked stable, so mark this one for stable
too.
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: stable@vger.kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
index 32b394f..6eb75b8 100644
--- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h
@@ -103,6 +103,11 @@
/* include/linux/interrupt.h needs hard_irq_disable to be a macro */
#define hard_irq_disable hard_irq_disable
+static inline bool lazy_irq_pending(void)
+{
+ return !!(get_paca()->irq_happened & ~PACA_IRQ_HARD_DIS);
+}
+
/*
* This is called by asynchronous interrupts to conditionally
* re-enable hard interrupts when soft-disabled after having