arm64: Add workaround for Cortex-A76 erratum 1286807

On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual address
for a cacheable mapping of a location is being accessed by a core while
another core is remapping the virtual address to a new physical page
using the recommended break-before-make sequence, then under very rare
circumstances TLBI+DSB completes before a read using the translation
being invalidated has been observed by other observers. The workaround
repeats the TLBI+DSB operation and is shared with the Qualcomm Falkor
erratum 1009
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Documentation/arm64/silicon-errata.txt

@@ -57,6 +57,7 @@ stable kernels.
 | ARM            | Cortex-A73      | #858921         | ARM64_ERRATUM_858921        |
 | ARM            | Cortex-A55      | #1024718        | ARM64_ERRATUM_1024718       |
 | ARM            | Cortex-A76      | #1188873        | ARM64_ERRATUM_1188873       |
+| ARM            | Cortex-A76      | #1286807        | ARM64_ERRATUM_1286807       |
 | ARM            | MMU-500         | #841119,#826419 | N/A                         |
 |                |                 |                 |                             |
 | Cavium         | ThunderX ITS    | #22375, #24313  | CAVIUM_ERRATUM_22375        |

arch/arm64/Kconfig

@@ -497,6 +497,24 @@ config ARM64_ERRATUM_1188873
 
 	  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
+	select ARM64_WORKAROUND_REPEAT_TLBI
+	help
+	  This option adds workaround for ARM Cortex-A76 erratum 1286807
+
+	  On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
+	  address for a cacheable mapping of a location is being
+	  accessed by a core while another core is remapping the virtual
+	  address to a new physical page using the recommended
+	  break-before-make sequence, then under very rare circumstances
+	  TLBI+DSB completes before a read using the translation being
+	  invalidated has been observed by other observers. The
+	  workaround repeats the TLBI+DSB operation.
+
+	  If unsure, say Y.
+
 config CAVIUM_ERRATUM_22375
 	bool "Cavium erratum 22375, 24313"
 	default y
@@ -566,9 +584,16 @@ config QCOM_FALKOR_ERRATUM_1003
 	  is unchanged. Work around the erratum by invalidating the walk cache
 	  entries for the trampoline before entering the kernel proper.
 
+config ARM64_WORKAROUND_REPEAT_TLBI
+	bool
+	help
+	  Enable the repeat TLBI workaround for Falkor erratum 1009 and
+	  Cortex-A76 erratum 1286807.
+
 config QCOM_FALKOR_ERRATUM_1009
 	bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
 	default y
+	select ARM64_WORKAROUND_REPEAT_TLBI
 	help
 	  On Falkor v1, the CPU may prematurely complete a DSB following a
 	  TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation

arch/arm64/include/asm/tlbflush.h

@@ -41,14 +41,14 @@
 		   ALTERNATIVE("nop\n			nop",		       \
 			       "dsb ish\n		tlbi " #op,	       \
 			       ARM64_WORKAROUND_REPEAT_TLBI,		       \
-			       CONFIG_QCOM_FALKOR_ERRATUM_1009)		       \
+			       CONFIG_ARM64_WORKAROUND_REPEAT_TLBI)	       \
 			    : : )
 
 #define __TLBI_1(op, arg) asm ("tlbi " #op ", %0\n"			       \
 		   ALTERNATIVE("nop\n			nop",		       \
 			       "dsb ish\n		tlbi " #op ", %0",     \
 			       ARM64_WORKAROUND_REPEAT_TLBI,		       \
-			       CONFIG_QCOM_FALKOR_ERRATUM_1009)		       \
+			       CONFIG_ARM64_WORKAROUND_REPEAT_TLBI)	       \
 			    : : "r" (arg))
 
 #define __TLBI_N(op, arg, n, ...) __TLBI_##n(op, arg)

arch/arm64/kernel/cpu_errata.c

@@ -570,6 +570,20 @@ static const struct midr_range arm64_harden_el2_vectors[] = {
 
 #endif
 
+#ifdef CONFIG_ARM64_WORKAROUND_REPEAT_TLBI
+
+static const struct midr_range arm64_repeat_tlbi_cpus[] = {
+#ifdef CONFIG_QCOM_FALKOR_ERRATUM_1009
+	MIDR_RANGE(MIDR_QCOM_FALKOR_V1, 0, 0, 0, 0),
+#endif
+#ifdef CONFIG_ARM64_ERRATUM_1286807
+	MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 3, 0),
+#endif
+	{},
+};
+
+#endif
+
 const struct arm64_cpu_capabilities arm64_errata[] = {
 #if	defined(CONFIG_ARM64_ERRATUM_826319) || \
 	defined(CONFIG_ARM64_ERRATUM_827319) || \
@@ -695,11 +709,11 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 		.matches = is_kryo_midr,
 	},
 #endif
-#ifdef CONFIG_QCOM_FALKOR_ERRATUM_1009
+#ifdef CONFIG_ARM64_WORKAROUND_REPEAT_TLBI
 	{
-		.desc = "Qualcomm Technologies Falkor erratum 1009",
+		.desc = "Qualcomm erratum 1009, ARM erratum 1286807",
 		.capability = ARM64_WORKAROUND_REPEAT_TLBI,
-		ERRATA_MIDR_REV(MIDR_QCOM_FALKOR_V1, 0, 0),
+		ERRATA_MIDR_RANGE_LIST(arm64_repeat_tlbi_cpus),
 	},
 #endif
 #ifdef CONFIG_ARM64_ERRATUM_858921