From: Russell King <rmk@dyn-67.arm.linux.org.uk>
Date: Wed, 27 Jul 2005 22:00:05 +0000 (+0100)
Subject: [ARM SMP] Fix data corruption in test_* bitops
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=614d73edae68836f7659ee8efec90878e6215fb1;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

[ARM SMP] Fix data corruption in test_* bitops

If we found that the bit was already in the desired state, we
would skip performing the operation, and write random data back.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---

diff --git a/arch/arm/lib/bitops.h b/arch/arm/lib/bitops.h
index 6976e60e47cb..5382a3023602 100644
--- a/arch/arm/lib/bitops.h
+++ b/arch/arm/lib/bitops.h
@@ -19,9 +19,9 @@
 	mov	r3, r2, lsl r3		@ create mask
 1:	ldrexb	r2, [r1]
 	ands	r0, r2, r3		@ save old value of bit
-	\instr	ip, r2, r3			@ toggle bit
-	strexb	r2, ip, [r1]
-	cmp	r2, #0
+	\instr	r2, r2, r3			@ toggle bit
+	strexb	ip, r2, [r1]
+	cmp	ip, #0
 	bne	1b
 	cmp	r0, #0
 	movne	r0, #1