linux-kernel - [PATCH 5/7] microblaze: Remove disabling IRQ while pte

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Message-Id: <79fa9cfeefc699b21f500c53279098b66275e2bb.1581522136.git.michal.simek@xilinx.com>
Date:   Wed, 12 Feb 2020 16:42:27 +0100
From:   Michal Simek <michal.simek@...inx.com>
To:     linux-kernel@...r.kernel.org, monstr@...str.eu,
        michal.simek@...inx.com, git@...inx.com, arnd@...db.de
Cc:     Stefan Asserhall <stefan.asserhall@...inx.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 5/7] microblaze: Remove disabling IRQ while pte_update() run

From: Stefan Asserhall <stefan.asserhall@...inx.com>

There is no need to disable local IRQ for pte update. Use exclusive
load/store instruction for it.

Signed-off-by: Stefan Asserhall <stefan.asserhall@...inx.com>
Signed-off-by: Michal Simek <michal.simek@...inx.com>
---

 arch/microblaze/include/asm/pgtable.h | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/arch/microblaze/include/asm/pgtable.h b/arch/microblaze/include/asm/pgtable.h
index 45b30878fc17..cf1e3095514b 100644
--- a/arch/microblaze/include/asm/pgtable.h
+++ b/arch/microblaze/include/asm/pgtable.h
@@ -372,20 +372,19 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 static inline unsigned long pte_update(pte_t *p, unsigned long clr,
 				unsigned long set)
 {
-	unsigned long flags, old, tmp;
-
-	raw_local_irq_save(flags);
-
-	__asm__ __volatile__(	"lw	%0, %2, r0	\n"
-				"andn	%1, %0, %3	\n"
-				"or	%1, %1, %4	\n"
-				"sw	%1, %2, r0	\n"
+	unsigned long old, tmp;
+
+	__asm__ __volatile__(
+			"1:	lwx	%0, %2, r0;\n"
+			"	andn	%1, %0, %3;\n"
+			"	or	%1, %1, %4;\n"
+			"	swx	%1, %2, r0;\n"
+			"	addic	%1, r0, 0;\n"
+			"	bnei	%1, 1b;\n"
 			: "=&r" (old), "=&r" (tmp)
 			: "r" ((unsigned long)(p + 1) - 4), "r" (clr), "r" (set)
 			: "cc");
 
-	raw_local_irq_restore(flags);
-
 	return old;
 }
 
-- 
2.25.0