ARM: 6743/1: errata: interrupted ICALLUIS may prevent completion of broadcasted operation

On versions of the Cortex-A9 prior to r3p0, an interrupted ICIALLUIS
operation may prevent the completion of a following broadcasted
operation if the second operation is received by a CPU before the
ICIALLUIS has completed, potentially leading to corrupted entries in
the cache or TLB.

This workaround sets a bit in the diagnostic register of the Cortex-A9,
causing CP15 maintenance operations to be uninterruptible.

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>

2 files changed, 16 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ba9fc213f344..166efa2a19cd 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1177,6 +1177,16 @@ config ARM_ERRATA_743622
           visible impact on the overall performance or power consumption of the
           processor.
 
+config ARM_ERRATA_751472
+        bool "ARM errata: Interrupted ICIALLUIS may prevent completion of broadcasted operation"
+        depends on CPU_V7 && SMP
+        help
+          This option enables the workaround for the 751472 Cortex-A9 (prior
+          to r3p0) erratum. An interrupted ICIALLUIS operation may prevent the
+          completion of a following broadcasted operation if the second
+          operation is received by a CPU before the ICIALLUIS has completed,
+          potentially leading to corrupted entries in the cache or TLB.
+
 config ARM_ERRATA_753970
         bool "ARM errata: cache sync operation may be faulty"
         depends on CACHE_PL310
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 0c1172b56b4e..8e3356239136 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -264,6 +264,12 @@ __v7_setup:
         orreq   r10, r10, #1 << 6               @ set bit #6
         mcreq   p15, 0, r10, c15, c0, 1         @ write diagnostic register
 #endif
+#ifdef CONFIG_ARM_ERRATA_751472
+        cmp     r6, #0x30                       @ present prior to r3p0
+        mrclt   p15, 0, r10, c15, c0, 1         @ read diagnostic register
+        orrlt   r10, r10, #1 << 11              @ set bit #11
+        mcrlt   p15, 0, r10, c15, c0, 1         @ write diagnostic register
+#endif
 
 3:      mov     r10, #0
 #ifdef HARVARD_CACHE