[PATCH for-stable-4.14 26/48] arm64: Add helpers for checking CPU MIDR against a range

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

From: Suzuki K Poulose <suzuki.poulose@arm.com>

[ Upstream commit 1df310505d6d544802016f6bae49aab836ae8510 ]

Add helpers for checking if the given CPU midr falls in a range
of variants/revisions for a given model.

Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm64/include/asm/cpufeature.h |  4 +--
 arch/arm64/include/asm/cputype.h    | 30 ++++++++++++++++++++
 arch/arm64/kernel/cpu_errata.c      | 18 +++++-------
 3 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 839aaa1505a3..ade058ada2b0 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -10,6 +10,7 @@
 #define __ASM_CPUFEATURE_H
 
 #include <asm/cpucaps.h>
+#include <asm/cputype.h>
 #include <asm/hwcap.h>
 #include <asm/sysreg.h>
 
@@ -302,8 +303,7 @@ struct arm64_cpu_capabilities {
 	void (*cpu_enable)(const struct arm64_cpu_capabilities *cap);
 	union {
 		struct {	/* To be used for erratum handling only */
-			u32 midr_model;
-			u32 midr_range_min, midr_range_max;
+			struct midr_range midr_range;
 		};
 
 		struct {	/* Feature register checking */
diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h
index 04569aa267fd..c60eb29ea261 100644
--- a/arch/arm64/include/asm/cputype.h
+++ b/arch/arm64/include/asm/cputype.h
@@ -125,6 +125,36 @@
 
 #define read_cpuid(reg)			read_sysreg_s(SYS_ ## reg)
 
+/*
+ * Represent a range of MIDR values for a given CPU model and a
+ * range of variant/revision values.
+ *
+ * @model	- CPU model as defined by MIDR_CPU_MODEL
+ * @rv_min	- Minimum value for the revision/variant as defined by
+ *		  MIDR_CPU_VAR_REV
+ * @rv_max	- Maximum value for the variant/revision for the range.
+ */
+struct midr_range {
+	u32 model;
+	u32 rv_min;
+	u32 rv_max;
+};
+
+#define MIDR_RANGE(m, v_min, r_min, v_max, r_max)		\
+	{							\
+		.model = m,					\
+		.rv_min = MIDR_CPU_VAR_REV(v_min, r_min),	\
+		.rv_max = MIDR_CPU_VAR_REV(v_max, r_max),	\
+	}
+
+#define MIDR_ALL_VERSIONS(m) MIDR_RANGE(m, 0, 0, 0xf, 0xf)
+
+static inline bool is_midr_in_range(u32 midr, struct midr_range const *range)
+{
+	return MIDR_IS_CPU_MODEL_RANGE(midr, range->model,
+				 range->rv_min, range->rv_max);
+}
+
 /*
  * The CPU ID never changes at run time, so we might as well tell the
  * compiler that it's constant.  Use this function to read the CPU ID
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 1e87e1427cc3..a3675d279b90 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -26,10 +26,10 @@
 static bool __maybe_unused
 is_affected_midr_range(const struct arm64_cpu_capabilities *entry, int scope)
 {
+	u32 midr = read_cpuid_id();
+
 	WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());
-	return MIDR_IS_CPU_MODEL_RANGE(read_cpuid_id(), entry->midr_model,
-				       entry->midr_range_min,
-				       entry->midr_range_max);
+	return is_midr_in_range(midr, &entry->midr_range);
 }
 
 static bool __maybe_unused
@@ -43,7 +43,7 @@ is_kryo_midr(const struct arm64_cpu_capabilities *entry, int scope)
 	model &= MIDR_IMPLEMENTOR_MASK | (0xf00 << MIDR_PARTNUM_SHIFT) |
 		 MIDR_ARCHITECTURE_MASK;
 
-	return model == entry->midr_model;
+	return model == entry->midr_range.model;
 }
 
 static bool
@@ -407,15 +407,11 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
 
 #define CAP_MIDR_RANGE(model, v_min, r_min, v_max, r_max)	\
 	.matches = is_affected_midr_range,			\
-	.midr_model = model,					\
-	.midr_range_min = MIDR_CPU_VAR_REV(v_min, r_min),	\
-	.midr_range_max = MIDR_CPU_VAR_REV(v_max, r_max)
+	.midr_range = MIDR_RANGE(model, v_min, r_min, v_max, r_max)
 
 #define CAP_MIDR_ALL_VERSIONS(model)					\
 	.matches = is_affected_midr_range,				\
-	.midr_model = model,						\
-	.midr_range_min = MIDR_CPU_VAR_REV(0, 0),			\
-	.midr_range_max = (MIDR_VARIANT_MASK | MIDR_REVISION_MASK)
+	.midr_range = MIDR_ALL_VERSIONS(model)
 
 #define MIDR_FIXED(rev, revidr_mask) \
 	.fixed_revs = (struct arm64_midr_revidr[]){{ (rev), (revidr_mask) }, {}}
@@ -556,7 +552,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 		.desc = "Qualcomm Technologies Kryo erratum 1003",
 		.capability = ARM64_WORKAROUND_QCOM_FALKOR_E1003,
 		.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
-		.midr_model = MIDR_QCOM_KRYO,
+		.midr_range.model = MIDR_QCOM_KRYO,
 		.matches = is_kryo_midr,
 	},
 #endif
-- 
2.20.1