[PATCH v3 5/7] powerpc/64s/interrupt: masked handler debug check for previous hard disable

[Nicholas Piggin]

Prior changes eliminated cases of masked PACA_IRQ_MUST_HARD_MASK
interrupts that re-fire due to MSR[EE] being enabled while they are
pending. Add a debug check in the masked interrupt handler to catch
if this occurs.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 arch/powerpc/kernel/exceptions-64s.S | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 3d0dc133a9ae..dafa275f18bc 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -2794,6 +2794,16 @@ masked_Hinterrupt:
 masked_interrupt:
 	.endif
 	stw	r9,PACA_EXGEN+EX_CCR(r13)
+#ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
+	/*
+	 * Ensure there was no previous MUST_HARD_MASK interrupt or
+	 * HARD_DIS setting.
+	 */
+	lbz	r9,PACAIRQHAPPENED(r13)
+	andi.	r9,r9,(PACA_IRQ_MUST_HARD_MASK|PACA_IRQ_HARD_DIS)
+0:	tdnei	r9,0
+	EMIT_BUG_ENTRY 0b,__FILE__,__LINE__,0
+#endif
 	lbz	r9,PACAIRQHAPPENED(r13)
 	or	r9,r9,r10
 	stb	r9,PACAIRQHAPPENED(r13)
-- 
2.37.2