[ARM] 5487/1: ARM errata: Stale prediction on replaced interworking branch
This patch adds the workaround for the 430973 Cortex-A8 (r1p0..r1p2)
erratum. The BTAC/BTB is now flushed at every context switch.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e28a76b..84e4816 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -749,6 +749,22 @@
It does not affect the MPCore. This option enables the ARM Ltd.
recommended workaround.
+config ARM_ERRATA_430973
+ bool "ARM errata: Stale prediction on replaced interworking branch"
+ depends on CPU_V7
+ help
+ This option enables the workaround for the 430973 Cortex-A8
+ (r1p0..r1p2) erratum. If a code sequence containing an ARM/Thumb
+ interworking branch is replaced with another code sequence at the
+ same virtual address, whether due to self-modifying code or virtual
+ to physical address re-mapping, Cortex-A8 does not recover from the
+ stale interworking branch prediction. This results in Cortex-A8
+ executing the new code sequence in the incorrect ARM or Thumb state.
+ The workaround enables the BTB/BTAC operations by setting ACTLR.IBE
+ and also flushes the branch target cache at every context switch.
+ Note that setting specific bits in the ACTLR register may not be
+ available in non-secure mode.
+
endmenu
source "arch/arm/common/Kconfig"