arm64: Handle mismatched cache type

commit 314d53d upstream.

Track mismatches in the cache type register (CTR_EL0), other
than the D/I min line sizes and trap user accesses if there are any.

Fixes: be68a8a ("arm64: cpufeature: Fix CTR_EL0 field definitions")
Cc: <stable@vger.kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Suzuki K Poulose

arch/arm64/include/asm/cpucaps.h

@@ -37,7 +37,8 @@
 #define ARM64_UNMAP_KERNEL_AT_EL0		16
 #define ARM64_HARDEN_BRANCH_PREDICTOR		17
 #define ARM64_SSBD				18
+#define ARM64_MISMATCHED_CACHE_TYPE		19
 
-#define ARM64_NCAPS				19
+#define ARM64_NCAPS				20
 
 #endif /* __ASM_CPUCAPS_H */

arch/arm64/kernel/cpu_errata.c

@@ -32,11 +32,15 @@ is_affected_midr_range(const struct arm64_cpu_capabilities *entry, int scope)
 }
 
 static bool
-has_mismatched_cache_line_size(const struct arm64_cpu_capabilities *entry,
-				int scope)
+has_mismatched_cache_type(const struct arm64_cpu_capabilities *entry,
+			  int scope)
 {
 	u64 mask = CTR_CACHE_MINLINE_MASK;
 
+	/* Skip matching the min line sizes for cache type check */
+	if (entry->capability == ARM64_MISMATCHED_CACHE_TYPE)
+		mask ^= arm64_ftr_reg_ctrel0.strict_mask;
+
 	WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());
 	return (read_cpuid_cachetype() & mask) !=
 	       (arm64_ftr_reg_ctrel0.sys_val & mask);
@@ -449,7 +453,14 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 	{
 		.desc = "Mismatched cache line size",
 		.capability = ARM64_MISMATCHED_CACHE_LINE_SIZE,
-		.matches = has_mismatched_cache_line_size,
+		.matches = has_mismatched_cache_type,
+		.def_scope = SCOPE_LOCAL_CPU,
+		.enable = cpu_enable_trap_ctr_access,
+	},
+	{
+		.desc = "Mismatched cache type",
+		.capability = ARM64_MISMATCHED_CACHE_TYPE,
+		.matches = has_mismatched_cache_type,
 		.def_scope = SCOPE_LOCAL_CPU,
 		.enable = cpu_enable_trap_ctr_access,
 	},