arm64: errata: Add Cortex-A55 to the repeat tlbi list

Cortex-A55 is affected by an erratum where in rare circumstances the
CPUs may not handle a race between a break-before-make sequence on one
CPU, and another CPU accessing the same page. This could allow a store
to a page that has been unmapped.

Work around this by adding the affected CPUs to the list that needs
TLB sequences to be done twice.

Signed-off-by: James Morse <james.morse@arm.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220930131959.3082594-1-james.morse@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1675310f1791..20d082d54bd8 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -634,6 +634,23 @@ config ARM64_ERRATUM_1530923
 config ARM64_WORKAROUND_REPEAT_TLBI
 	bool
 
+config ARM64_ERRATUM_2441007
+	bool "Cortex-A55: Completion of affected memory accesses might not be guaranteed by completion of a TLBI"
+	default y
+	select ARM64_WORKAROUND_REPEAT_TLBI
+	help
+	  This option adds a workaround for ARM Cortex-A55 erratum #2441007.
+
+	  Under very rare circumstances, affected Cortex-A55 CPUs
+	  may not handle a race between a break-before-make sequence on one
+	  CPU, and another CPU accessing the same page. This could allow a
+	  store to a page that has been unmapped.
+
+	  Work around this by adding the affected CPUs to the list that needs
+	  TLB sequences to be done twice.
+
+	  If unsure, say Y.
+
 config ARM64_ERRATUM_1286807
 	bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
 	default y