[PATCH 3/5] powerpc/64: warn if local irqs are enabled in NMI or hardirq context

[Nicholas Piggin <npiggin@gmail.com>]

This can help catch bugs such as the one fixed by the previous change
to prevent _exception() from enabling irqs.

ppc32 could have a similar warning but it has no good config option to
debug this stuff (the test may be overkill to add for production
kernels).

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/kernel/irq.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 551b653228c4..c4f1d6b7d992 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -229,6 +229,9 @@ notrace void arch_local_irq_restore(unsigned long mask)
 		return;
 	}
 
+	if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG))
+		WARN_ON_ONCE(in_nmi() || in_hardirq());
+
 	/*
 	 * After the stb, interrupts are unmasked and there are no interrupts
 	 * pending replay. The restart sequence makes this atomic with
@@ -321,6 +324,9 @@ notrace void arch_local_irq_restore(unsigned long mask)
 	if (mask)
 		return;
 
+	if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG))
+		WARN_ON_ONCE(in_nmi() || in_hardirq());
+
 	/*
 	 * From this point onward, we can take interrupts, preempt,
 	 * etc... unless we got hard-disabled. We check if an event
-- 
2.23.0