From: Thomas Petazzoni Date: Tue, 25 Nov 2014 17:43:15 +0000 (+0100) Subject: ARM: 8222/1: mvebu: enable strex backoff delay X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6e1baa82767fb291617f442393c8ec0f31ef0e31;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git 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 Signed-off-by: Thomas Petazzoni Acked-by: Gregory CLEMENT Acked-by: Jason Cooper Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index 19da84172cc3..4562ebf8449d 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -201,7 +201,6 @@ __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 */ @@ -224,7 +223,6 @@ __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