430973: Stale prediction on replaced inter working branch causes Cortex-A8 to execute in the wrong ARM/Thumb state Impacts: Every Cortex-A8 processors with revision lower than r2p1 Work around: Set IBE to 1
Based on ARM errata Document revision 20.0 (13 Nov 2010)
Signed-off-by: Nishanth Menon nm@ti.com --- README | 1 + arch/arm/cpu/armv7/start.S | 13 +++++++++++++ 2 files changed, 14 insertions(+)
diff --git a/README b/README index e538cf061286..484ae9ee39a8 100644 --- a/README +++ b/README @@ -624,6 +624,7 @@ The following options need to be configured: NOTE: The following can be machine specific errata. These do have ability to provide rudimentary version and machine specific checks, but expect no product checks. + CONFIG_ARM_ERRATA_430973 CONFIG_ARM_ERRATA_454179 CONFIG_ARM_ERRATA_798870
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S index 1516ed675dac..99220ce76a25 100644 --- a/arch/arm/cpu/armv7/start.S +++ b/arch/arm/cpu/armv7/start.S @@ -198,6 +198,19 @@ skip_errata_798870: skip_errata_454179: #endif
+#ifdef CONFIG_ARM_ERRATA_430973 + cmp r2, #0x21 @ Only on < r2p1 + bge skip_errata_430973 + + mrc p15, 0, r0, c1, c0, 1 @ Read ACR + orr r0, r0, #(0x1 << 6) @ Set IBE bit + push {r1-r4} @ Save the cpu info registers + b v7_arch_cp15_set_acr + pop {r1-r4} @ Restore the cpu info - fall through + +skip_errata_430973: +#endif + mov pc, lr @ back to my caller ENDPROC(cpu_init_cp15)