linux-kernel - [PATCH] powerpc/irq: remove inline assembly in hard_irq

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Message-Id: <9f05937d8722ddd2064a7c2362d8f9000e15e1ba.1652863723.git.christophe.leroy@csgroup.eu>
Date:   Wed, 18 May 2022 10:48:55 +0200
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     Christophe Leroy <christophe.leroy@...roup.eu>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH] powerpc/irq: remove inline assembly in hard_irq_disable macro

Use WRITE_ONCE() instead of opencoding the saving of current
stack pointeur.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
By the way, is WRITE_ONCE() needed at all ? Could we instead do local_paca->saved_r1 = current_stack_pointer;
---
 arch/powerpc/include/asm/hw_irq.h | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
index 6efab00aa1c8..26ede09c521d 100644
--- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h
@@ -282,9 +282,7 @@ static inline bool pmi_irq_pending(void)
 	flags = irq_soft_mask_set_return(IRQS_ALL_DISABLED);		\
 	local_paca->irq_happened |= PACA_IRQ_HARD_DIS;			\
 	if (!arch_irqs_disabled_flags(flags)) {				\
-		asm ("stdx %%r1, 0, %1 ;"				\
-		     : "=m" (local_paca->saved_r1)			\
-		     : "b" (&local_paca->saved_r1));			\
+		WRITE_ONCE(local_paca->saved_r1, current_stack_pointer);\
 		trace_hardirqs_off();					\
 	}								\
 } while(0)
-- 
2.35.3