If a NMI hits early in an interrupt handler before the irq soft-mask
state is reconciled, that can cause a false-positive BUG with a
CONFIG_PPC_IRQ_SOFT_MASK_DEBUG assertion.

Remove that assertion and instead check the case that if regs->msr has
EE clear, then regs->softe should be marked as disabled so the irq state
looks correct to NMI handlers, the same as how it's fixed up in the
case it was implicit soft-masked.

Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
 arch/powerpc/include/asm/interrupt.h | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/interrupt.h 
b/arch/powerpc/include/asm/interrupt.h
index b32ed910a8cf..b76ab848aa0d 100644
--- a/arch/powerpc/include/asm/interrupt.h
+++ b/arch/powerpc/include/asm/interrupt.h
@@ -265,13 +265,16 @@ static inline void interrupt_nmi_enter_prepare(struct 
pt_regs *regs, struct inte
        local_paca->irq_soft_mask = IRQS_ALL_DISABLED;
        local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
 
-       if (is_implicit_soft_masked(regs)) {
-               // Adjust regs->softe soft implicit soft-mask, so
-               // arch_irq_disabled_regs(regs) behaves as expected.
+       if (!(regs->msr & MSR_EE) || is_implicit_soft_masked(regs)) {
+               /*
+                * Adjust regs->softe to be soft-masked if it had not been
+                * reconcied (e.g., interrupt entry with MSR[EE]=0 but softe
+                * not yet set disabled), or if it was in an implicit soft
+                * masked state. This makes arch_irq_disabled_regs(regs)
+                * behave as expected.
+                */
                regs->softe = IRQS_ALL_DISABLED;
        }
-       if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG))
-               BUG_ON(!arch_irq_disabled_regs(regs) && !(regs->msr & MSR_EE));
 
        /* Don't do any per-CPU operations until interrupt state is fixed */
 
-- 
2.23.0

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