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irqchip/gic-v3: Make sure read from ICC_IAR1_EL1 is visible on redestributor

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[ Upstream commit 1a1ebd5fb1e203ee8cc73508cc7a38ac4b804596 ]

The ARM GICv3 specification mentions the need for dsb after a read
from the ICC_IAR1_EL1 register:

	4.1.1 Physical CPU Interface:
	The effects of reading ICC_IAR0_EL1 and ICC_IAR1_EL1
	on the state of a returned INTID are not guaranteed
	to be visible until after the execution of a DSB.

Not having this could result in missed interrupts, so let's add the
required barrier.

[Marc: fixed commit message]

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Tirumalesh Chalamarla <tchalamarla@caviumnetworks.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tirumalesh Chalamarla 2016-02-04 10:45:25 -08:00 committed by Greg Kroah-Hartman
parent e941af922e
commit d5251a1952
1 changed files with 1 additions and 0 deletions
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arch/arm64/include/asm/arch_gicv3.h
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@ -103,6 +103,7 @@ static inline u64 gic_read_iar_common(void)
u64 irqstat;
asm volatile("mrs_s %0, " __stringify(ICC_IAR1_EL1) : "=r" (irqstat));
dsb(sy);
return irqstat;
}