ARM: 7091/1: errata: D-cache line maintenance operation by MVA may not succeed

This patch implements a workaround for erratum 764369 affecting
Cortex-A9 MPCore with two or more processors (all current revisions).
Under certain timing circumstances, a data cache line maintenance
operation by MVA targeting an Inner Shareable memory region may fail to
proceed up to either the Point of Coherency or to the Point of
Unification of the system. This workaround adds a DSB instruction before
the relevant cache maintenance functions and sets a specific bit in the
diagnostic control register of the SCU.

Cc: <stable@kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 3269576dbfa8..3146ed3f6eca 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1283,6 +1283,20 @@ config ARM_ERRATA_364296
           processor into full low interrupt latency mode. ARM11MPCore
           is not affected.
 
+config ARM_ERRATA_764369
+        bool "ARM errata: Data cache line maintenance operation by MVA may not succeed"
+        depends on CPU_V7 && SMP
+        help
+          This option enables the workaround for erratum 764369
+          affecting Cortex-A9 MPCore with two or more processors (all
+          current revisions). Under certain timing circumstances, a data
+          cache line maintenance operation by MVA targeting an Inner
+          Shareable memory region may fail to proceed up to either the
+          Point of Coherency or to the Point of Unification of the
+          system. This workaround adds a DSB instruction before the
+          relevant cache maintenance functions and sets a specific bit
+          in the diagnostic control register of the SCU.
+
 endmenu
 
 source "arch/arm/common/Kconfig"