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authorThomas Petazzoni <thomas.petazzoni@free-electrons.com>2014-11-25 18:43:15 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-12-06 15:55:37 -0800
commitc84eb54a06e525d9b290a2c80fdd42f06d2c0380 (patch)
tree9bd021534f48b674454e52ec7f98b5fb418530ad
parent80eb5395671d378f308aa68599f96089c1427b1f (diff)
ARM: 8222/1: mvebu: enable strex backoff delay
commit 995ab5189d1d7264e79e665dfa032a19b3ac646e upstream. 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") 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/arm/mm/proc-v7.S2
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 74f6033e76dd..fdedc31e0f40 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -211,7 +211,6 @@ __v7_pj4b_setup:
/* Auxiliary Debug Modes Control 1 Register */
#define PJ4B_STATIC_BP (1 << 2) /* Enable Static BP */
#define PJ4B_INTER_PARITY (1 << 8) /* Disable Internal Parity Handling */
-#define PJ4B_BCK_OFF_STREX (1 << 5) /* Enable the back off of STREX instr */
#define PJ4B_CLEAN_LINE (1 << 16) /* Disable data transfer for clean line */
/* Auxiliary Debug Modes Control 2 Register */
@@ -234,7 +233,6 @@ __v7_pj4b_setup:
/* Auxiliary Debug Modes Control 1 Register */
mrc p15, 1, r0, c15, c1, 1
orr r0, r0, #PJ4B_CLEAN_LINE
- orr r0, r0, #PJ4B_BCK_OFF_STREX
orr r0, r0, #PJ4B_INTER_PARITY
bic r0, r0, #PJ4B_STATIC_BP
mcr p15, 1, r0, c15, c1, 1