[PATCH] arm64: errata: Add Cortex-A510 to the repeat tlbi list

[James Morse]

Cortex-A510 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 at arm.com>
---
I opted to add this as a new entry, as the writeup isn't the same as
the similar erratum on A76.

 Documentation/arm64/silicon-errata.rst |  2 ++
 arch/arm64/Kconfig                     | 17 +++++++++++++++++
 arch/arm64/kernel/cpu_errata.c         |  8 +++++++-
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst
index d27db84d585e..250306a37a65 100644
--- a/Documentation/arm64/silicon-errata.rst
+++ b/Documentation/arm64/silicon-errata.rst
@@ -102,6 +102,8 @@ stable kernels.
 +----------------+-----------------+-----------------+-----------------------------+
 | ARM            | Cortex-A510     | #2077057        | ARM64_ERRATUM_2077057       |
 +----------------+-----------------+-----------------+-----------------------------+
+| ARM            | Cortex-A510     | #2441009        | ARM64_ERRATUM_2441009       |
++----------------+-----------------+-----------------+-----------------------------+
 | ARM            | Cortex-A710     | #2119858        | ARM64_ERRATUM_2119858       |
 +----------------+-----------------+-----------------+-----------------------------+
 | ARM            | Cortex-A710     | #2054223        | ARM64_ERRATUM_2054223       |
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1652a9800ebe..0ed35959b090 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -821,6 +821,23 @@ config ARM64_ERRATUM_2224489
 
 	  If unsure, say Y.
 
+config ARM64_ERRATUM_2441009
+	bool "Cortex-A510: 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-A510 erratum #2441009.
+
+	  Under very rare circumstances, affected Cortex-A510 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_2064142
 	bool "Cortex-A510: 2064142: workaround TRBE register writes while disabled"
 	depends on CORESIGHT_TRBE
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index c05cc3b6162e..c846cf1814b7 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -211,6 +211,12 @@ static const struct arm64_cpu_capabilities arm64_repeat_tlbi_list[] = {
 		/* Kryo4xx Gold (rcpe to rfpe) => (r0p0 to r3p0) */
 		ERRATA_MIDR_RANGE(MIDR_QCOM_KRYO_4XX_GOLD, 0xc, 0xe, 0xf, 0xe),
 	},
+#endif
+#ifdef CONFIG_ARM64_ERRATUM_2441009
+	{
+		/* Cortex-A510 r0p0 -> r1p1. Fixed in r1p2 */
+		ERRATA_MIDR_RANGE(MIDR_CORTEX_A510, 0, 0, 1, 1),
+	},
 #endif
 	{},
 };
@@ -480,7 +486,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 #endif
 #ifdef CONFIG_ARM64_WORKAROUND_REPEAT_TLBI
 	{
-		.desc = "Qualcomm erratum 1009, or ARM erratum 1286807",
+		.desc = "Qualcomm erratum 1009, or ARM erratum 1286807, 2441009",
 		.capability = ARM64_WORKAROUND_REPEAT_TLBI,
 		.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
 		.matches = cpucap_multi_entry_cap_matches,
-- 
2.30.2