ARM: 6416/1: errata: faulty hazard checking in the Store Buffer may lead to data corruption

On the r2p0, r2p1 and r2p2 versions of the Cortex-A9, data corruption
can occur under very rare conditions due to a store buffer optimisation.

This workaround sets a bit in the diagnostic register of the Cortex-A9,
disabling the optimisation and preventing the problem from occurring.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@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 88c97bc7a6f5..9c26ba7244fb 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1101,6 +1101,20 @@ config ARM_ERRATA_720789
 	  invalidated are not, resulting in an incoherency in the system page
 	  tables. The workaround changes the TLB flushing routines to invalidate
 	  entries regardless of the ASID.
+
+config ARM_ERRATA_743622
+	bool "ARM errata: Faulty hazard checking in the Store Buffer may lead to data corruption"
+	depends on CPU_V7
+	help
+	  This option enables the workaround for the 743622 Cortex-A9
+	  (r2p0..r2p2) erratum. Under very rare conditions, a faulty
+	  optimisation in the Cortex-A9 Store Buffer may lead to data
+	  corruption. This workaround sets a specific bit in the diagnostic
+	  register of the Cortex-A9 which disables the Store Buffer
+	  optimisation, preventing the defect from occurring. This has no
+	  visible impact on the overall performance or power consumption of the
+	  processor.
+
 endmenu
 
 source "arch/arm/common/Kconfig"