ARM: 8222/1: mvebu: enable strex backoff delay
authorThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Tue, 25 Nov 2014 17:43:15 +0000 (18:43 +0100)
committerRussell King <rmk+kernel@arm.linux.org.uk>
Thu, 27 Nov 2014 15:55:04 +0000 (15:55 +0000)
commit995ab5189d1d7264e79e665dfa032a19b3ac646e
treeaf6bdd7b1b1c9c7698af2c1d54661890be677ef8
parentef59a20ba375aeb97b3150a118318884743452a8
ARM: 8222/1: mvebu: enable strex backoff delay

Under extremely rare conditions, in an MPCore node consisting of at
least 3 CPUs, two CPUs trying to perform a STREX to data on the same
shared cache line can enter a livelock situation.

This patch enables the HW mechanism that overcomes the bug. This fixes
the incorrect setup of the STREX backoff delay bit due to a wrong
description in the specification.

Note that enabling the STREX backoff delay mechanism is done by
leaving the bit *cleared*, while the bit was currently being set by
the proc-v7.S code.

[Thomas: adapt to latest mainline, slightly reword the commit log, add
stable markers.]

Fixes: de4901933f6d ("arm: mm: Add support for PJ4B cpu and init routines")
Cc: <stable@vger.kernel.org> # v3.8+
Signed-off-by: Nadav Haklai <nadavh@marvell.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arch/arm/mm/proc-v7.S