From b60b61d41220c8d34e2c62a748bc78bc5d40585e Mon Sep 17 00:00:00 2001 From: Nadav Haklai Date: Thu, 23 May 2013 10:54:02 +0200 Subject: [PATCH] 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 Signed-off-by: Gregory CLEMENT Signed-off-by: Jason Cooper --- arch/arm/mach-mvebu/coherency_ll.S | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/arch/arm/mach-mvebu/coherency_ll.S b/arch/arm/mach-mvebu/coherency_ll.S index 53e8391192cd..5476669ba905 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