linux-kernel - [PATCH 2/2] arm64: Handle mismatched cache type

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Date:   Wed,  4 Jul 2018 23:07:46 +0100
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, suzuki.poulose@....com,
        will.deacon@....com, mark.rutland@....com,
        ard.biesheuvel@...aro.org, catalin.marinas@....com,
        dave.martin@....com
Subject: [PATCH 2/2] arm64: Handle mismatched cache type

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.

Cc: Mark Rutland <mark.rutland@....com>
Cc: Will Deacon <will.deacon@....com>
Cc: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
---
 arch/arm64/include/asm/cpucaps.h |  3 ++-
 arch/arm64/kernel/cpu_errata.c   | 17 ++++++++++++++---
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index 8a699c7..be3bf3d 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -49,7 +49,8 @@
 #define ARM64_HAS_CACHE_DIC			28
 #define ARM64_HW_DBM				29
 #define ARM64_SSBD				30
+#define ARM64_MISMATCHED_CACHE_TYPE		31
 
-#define ARM64_NCAPS				31
+#define ARM64_NCAPS				32
 
 #endif /* __ASM_CPUCAPS_H */
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 5d1fa92..5d59ff9 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -65,11 +65,15 @@ is_kryo_midr(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);
@@ -615,7 +619,14 @@ 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,
+		.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
+		.cpu_enable = cpu_enable_trap_ctr_access,
+	},
+	{
+		.desc = "Mismatched cache type",
+		.capability = ARM64_MISMATCHED_CACHE_TYPE,
+		.matches = has_mismatched_cache_type,
 		.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
 		.cpu_enable = cpu_enable_trap_ctr_access,
 	},
-- 
2.9.5