Subject: [PATCH v2 04/14] powerpc/64: cleanup __check_irq_replay

From: Nicholas Piggin <[email-masked]>
Date: Sat, 12 Aug 2017 02:39:02 +1000

Move the clearing of irq_happened bits into the condition where
they were found to be set. This reduces instruction count slightly,
and reduces stores into irq_happened.

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/kernel/irq.c | 45 +++++++++++++++++++++++----------------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index f291f7826abc..7c46e0cce054 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -143,9 +143,10 @@ notrace unsigned int __check_irq_replay(void)
 	 */
 	unsigned char happened = local_paca->irq_happened;
 
-	/* Clear bit 0 which we wouldn't clear otherwise */
-	local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
 	if (happened & PACA_IRQ_HARD_DIS) {
+		/* Clear bit 0 which we wouldn't clear otherwise */
+		local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
+
 		/*
 		 * We may have missed a decrementer interrupt if hard disabled.
 		 * Check the decrementer register in case we had a rollover
@@ -173,39 +174,39 @@ notrace unsigned int __check_irq_replay(void)
 	 * This is a higher priority interrupt than the others, so
 	 * replay it first.
 	 */
-	local_paca->irq_happened &= ~PACA_IRQ_HMI;
-	if (happened & PACA_IRQ_HMI)
+	if (happened & PACA_IRQ_HMI) {
+		local_paca->irq_happened &= ~PACA_IRQ_HMI;
 		return 0xe60;
+	}
 
-	/*
-	 * We may have missed a decrementer interrupt. We check the
-	 * decrementer itself rather than the paca irq_happened field
-	 * in case we also had a rollover while hard disabled
-	 */
-	local_paca->irq_happened &= ~PACA_IRQ_DEC;
-	if (happened & PACA_IRQ_DEC)
+	if (happened & PACA_IRQ_DEC) {
+		local_paca->irq_happened &= ~PACA_IRQ_DEC;
 		return 0x900;
+	}
 
-	/* Finally check if an external interrupt happened */
-	local_paca->irq_happened &= ~PACA_IRQ_EE;
-	if (happened & PACA_IRQ_EE)
+	if (happened & PACA_IRQ_EE) {
+		local_paca->irq_happened &= ~PACA_IRQ_EE;
 		return 0x500;
+	}
 
 #ifdef CONFIG_PPC_BOOK3E
-	/* Finally check if an EPR external interrupt happened
-	 * this bit is typically set if we need to handle another
-	 * "edge" interrupt from within the MPIC "EPR" handler
+	/*
+	 * Check if an EPR external interrupt happened this bit is typically
+	 * set if we need to handle another "edge" interrupt from within the
+	 * MPIC "EPR" handler.
 	 */
-	local_paca->irq_happened &= ~PACA_IRQ_EE_EDGE;
-	if (happened & PACA_IRQ_EE_EDGE)
+	if (happened & PACA_IRQ_EE_EDGE) {
+		local_paca->irq_happened &= ~PACA_IRQ_EE_EDGE;
 		return 0x500;
+	}
 
-	local_paca->irq_happened &= ~PACA_IRQ_DBELL;
-	if (happened & PACA_IRQ_DBELL)
+	if (happened & PACA_IRQ_DBELL) {
+		local_paca->irq_happened &= ~PACA_IRQ_DBELL;
 		return 0x280;
+	}
 #else
-	local_paca->irq_happened &= ~PACA_IRQ_DBELL;
 	if (happened & PACA_IRQ_DBELL) {
+		local_paca->irq_happened &= ~PACA_IRQ_DBELL;
 		if (cpu_has_feature(CPU_FTR_HVMODE))
 			return 0xe80;
 		return 0xa00;
-- 
2.13.3