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>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 88c97bc..9c26ba7 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1101,6 +1101,20 @@
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"
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 7563ff0..75619c5 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -253,6 +253,14 @@
orreq r10, r10, #1 << 22 @ set bit #22
mcreq p15, 0, r10, c15, c0, 1 @ write diagnostic register
#endif
+#ifdef CONFIG_ARM_ERRATA_743622
+ teq r6, #0x20 @ present in r2p0
+ teqne r6, #0x21 @ present in r2p1
+ teqne r6, #0x22 @ present in r2p2
+ mrceq p15, 0, r10, c15, c0, 1 @ read diagnostic register
+ orreq r10, r10, #1 << 6 @ set bit #6
+ mcreq p15, 0, r10, c15, c0, 1 @ write diagnostic register
+#endif
3: mov r10, #0
#ifdef HARVARD_CACHE