powerpc/irq: Don't WARN continuously in arch_local_irq_restore()

When CONFIG_PPC_IRQ_SOFT_MASK_DEBUG is enabled (uncommon), we have a
series of WARN_ON's in arch_local_irq_restore().

These are "should never happen" conditions, but if they do happen they
can flood the console and render the system unusable. So switch them
to WARN_ON_ONCE().

Fixes: e2b36d591720 ("powerpc/64: Don't trace code that runs with the soft irq mask unreconciled")
Fixes: 9b81c0211c24 ("powerpc/64s: make PACA_IRQ_HARD_DIS track MSR[EE] closely")
Fixes: 7c0482e3d055 ("powerpc/irq: Fix another case of lazy IRQ state getting out of sync")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190708061046.7075-1-mpe@ellerman.id.au

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index ada901a..c9a6eac 100644 (file)
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -259,7 +259,7 @@ notrace void arch_local_irq_restore(unsigned long mask)
        irq_happened = get_irq_happened();
        if (!irq_happened) {
 #ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
-               WARN_ON(!(mfmsr() & MSR_EE));
+               WARN_ON_ONCE(!(mfmsr() & MSR_EE));
 #endif
                return;
        }
@@ -272,7 +272,7 @@ notrace void arch_local_irq_restore(unsigned long mask)
         */
        if (!(irq_happened & PACA_IRQ_HARD_DIS)) {
 #ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
-               WARN_ON(!(mfmsr() & MSR_EE));
+               WARN_ON_ONCE(!(mfmsr() & MSR_EE));
 #endif
                __hard_irq_disable();
 #ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
@@ -283,7 +283,7 @@ notrace void arch_local_irq_restore(unsigned long mask)
                 * warn if we are wrong. Only do that when IRQ tracing
                 * is enabled as mfmsr() can be costly.
                 */
-               if (WARN_ON(mfmsr() & MSR_EE))
+               if (WARN_ON_ONCE(mfmsr() & MSR_EE))
                        __hard_irq_disable();
 #endif
        }