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authorNadav Haklai <nadavh@marvell.com>2013-05-23 10:54:02 +0200
committerJason Cooper <jason@lakedaemon.net>2013-05-28 14:50:08 +0000
commitb60b61d41220c8d34e2c62a748bc78bc5d40585e (patch)
tree577e002b7826bd271580a6e34c41028895ec1d2b /arch/arm
parente89b4058096569c999fa599370162022a5a2b3d2 (diff)
downloadop-kernel-dev-b60b61d41220c8d34e2c62a748bc78bc5d40585e.zip
op-kernel-dev-b60b61d41220c8d34e2c62a748bc78bc5d40585e.tar.gz
ARM: mvebu: Fix bug in coherency fabric low level init function
When adding CPU to the SMP group and enabling the coherency on this CPU we must protect the register access. The previous implementation claims to be atomic but doesn't provide any protection against parallel access to the coherency fabric control and configuration registers. This patch fixes this by using the ldrex and strex mechanism. This method should be used in all accesses to those registers. [gregory.clement@free-electrons.com: fixed the commit's topic] Signed-off-by: Nadav Haklai <nadavh@marvell.com> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com> Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/mach-mvebu/coherency_ll.S16
1 files changed, 11 insertions, 5 deletions
diff --git a/arch/arm/mach-mvebu/coherency_ll.S b/arch/arm/mach-mvebu/coherency_ll.S
index 53e8391..5476669 100644
--- a/arch/arm/mach-mvebu/coherency_ll.S
+++ b/arch/arm/mach-mvebu/coherency_ll.S
@@ -32,15 +32,21 @@ ENTRY(ll_set_cpu_coherent)
/* Add CPU to SMP group - Atomic */
add r3, r0, #ARMADA_XP_CFB_CTL_REG_OFFSET
- ldr r2, [r3]
+1:
+ ldrex r2, [r3]
orr r2, r2, r1
- str r2, [r3]
+ strex r0, r2, [r3]
+ cmp r0, #0
+ bne 1b
/* Enable coherency on CPU - Atomic */
- add r3, r0, #ARMADA_XP_CFB_CFG_REG_OFFSET
- ldr r2, [r3]
+ add r3, r3, #ARMADA_XP_CFB_CFG_REG_OFFSET
+1:
+ ldrex r2, [r3]
orr r2, r2, r1
- str r2, [r3]
+ strex r0, r2, [r3]
+ cmp r0, #0
+ bne 1b
dsb
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