[PATCH v2 0/3] arm64: cpufeature: constify and refactor feature array

[PATCH v2 0/3] arm64: cpufeature: constify and refactor feature array

[Ard Biesheuvel]

This is v2 of the series that constifies and refactors the cpufeatures data
structures, in a way that allows certain pieces to be referenced directly by
external code. This was triggered by the discussion around Suzuki's CTR
emulation series [0]

Changes since v1/RFC:
- replace 'if (<cond>) { BUG(); }' with 'BUG_ON(<cond>);' (#2)
- don't dereference NULL return value of bsearch() (#2)
- rename global ctrel0_ftr_reg to arm64_ftr_reg_ctrel0 (#3)
- add Suzuki's R-b (#1, #2, #3)

[0] http://marc.info/?l=linux-arm-kernel&m=147152604303792&w=2

Ard Biesheuvel (3):
  arm64: cpufeature: constify arm64_ftr_bits structures
  arm64: cpufeature: constify arm64_ftr_regs array
  arm64: cpufeature: expose arm64_ftr_reg struct for CTR_EL0

 arch/arm64/include/asm/cpufeature.h | 15 +--
 arch/arm64/kernel/cpufeature.c      | 99 ++++++++++----------
 2 files changed, 58 insertions(+), 56 deletions(-)

-- 
2.7.4

[PATCH v2 1/3] arm64: cpufeature: constify arm64_ftr_bits structures

[Ard Biesheuvel]

The arm64_ftr_bits structures are never modified, so make them read-only.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm64/include/asm/cpufeature.h | 14 +++---
 arch/arm64/kernel/cpufeature.c      | 46 ++++++++++----------
 2 files changed, 31 insertions(+), 29 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 7099f26e3702..7c0b7cff17df 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -72,11 +72,11 @@ struct arm64_ftr_bits {
  * @sys_val		Safe value across the CPUs (system view)
  */
 struct arm64_ftr_reg {
-	u32			sys_id;
-	const char		*name;
-	u64			strict_mask;
-	u64			sys_val;
-	struct arm64_ftr_bits	*ftr_bits;
+	u32				sys_id;
+	const char			*name;
+	u64				strict_mask;
+	u64				sys_val;
+	const struct arm64_ftr_bits	*ftr_bits;
 };
 
 /* scope of capability check */
@@ -157,7 +157,7 @@ cpuid_feature_extract_unsigned_field(u64 features, int field)
 	return cpuid_feature_extract_unsigned_field_width(features, field, 4);
 }
 
-static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp)
+static inline u64 arm64_ftr_mask(const struct arm64_ftr_bits *ftrp)
 {
 	return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
 }
@@ -170,7 +170,7 @@ cpuid_feature_extract_field(u64 features, int field, bool sign)
 		cpuid_feature_extract_unsigned_field(features, field);
 }
 
-static inline s64 arm64_ftr_value(struct arm64_ftr_bits *ftrp, u64 val)
+static inline s64 arm64_ftr_value(const struct arm64_ftr_bits *ftrp, u64 val)
 {
 	return (s64)cpuid_feature_extract_field(val, ftrp->shift, ftrp->sign);
 }
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 62272eac1352..eac76cb3a206 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -74,7 +74,7 @@ static bool __maybe_unused
 cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused);
 
 
-static struct arm64_ftr_bits ftr_id_aa64isar0[] = {
+static const struct arm64_ftr_bits ftr_id_aa64isar0[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 32, 32, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_AA64ISAR0_RDM_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 24, 4, 0),
@@ -87,7 +87,7 @@ static struct arm64_ftr_bits ftr_id_aa64isar0[] = {
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
+static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 32, 32, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 28, 4, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_AA64PFR0_GIC_SHIFT, 4, 0),
@@ -101,7 +101,7 @@ static struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
+static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 32, 32, 0),
 	S_ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_AA64MMFR0_TGRAN4_SHIFT, 4, ID_AA64MMFR0_TGRAN4_NI),
 	S_ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_AA64MMFR0_TGRAN64_SHIFT, 4, ID_AA64MMFR0_TGRAN64_NI),
@@ -119,7 +119,7 @@ static struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
+static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 32, 32, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_PAN_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_AA64MMFR1_LOR_SHIFT, 4, 0),
@@ -130,7 +130,7 @@ static struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
+static const struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_AA64MMFR2_LVA_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_AA64MMFR2_IESB_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_AA64MMFR2_LSM_SHIFT, 4, 0),
@@ -139,7 +139,7 @@ static struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_ctr[] = {
+static const struct arm64_ftr_bits ftr_ctr[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 31, 1, 1),	/* RAO */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 28, 3, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_HIGHER_SAFE, 24, 4, 0),	/* CWG */
@@ -155,7 +155,7 @@ static struct arm64_ftr_bits ftr_ctr[] = {
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_id_mmfr0[] = {
+static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
 	S_ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 28, 4, 0xf),	/* InnerShr */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 24, 4, 0),	/* FCSE */
 	ARM64_FTR_BITS(FTR_NONSTRICT, FTR_LOWER_SAFE, 20, 4, 0),	/* AuxReg */
@@ -167,7 +167,7 @@ static struct arm64_ftr_bits ftr_id_mmfr0[] = {
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
+static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 32, 32, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_CTX_CMPS_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_WRPS_SHIFT, 4, 0),
@@ -178,14 +178,14 @@ static struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_mvfr2[] = {
+static const struct arm64_ftr_bits ftr_mvfr2[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 8, 24, 0),	/* RAZ */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 4, 4, 0),		/* FPMisc */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 0, 4, 0),		/* SIMDMisc */
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_dczid[] = {
+static const struct arm64_ftr_bits ftr_dczid[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 5, 27, 0),	/* RAZ */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 4, 1, 1),		/* DZP */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),	/* BS */
@@ -193,7 +193,7 @@ static struct arm64_ftr_bits ftr_dczid[] = {
 };
 
 
-static struct arm64_ftr_bits ftr_id_isar5[] = {
+static const struct arm64_ftr_bits ftr_id_isar5[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_ISAR5_RDM_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 20, 4, 0),	/* RAZ */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_ISAR5_CRC32_SHIFT, 4, 0),
@@ -204,14 +204,14 @@ static struct arm64_ftr_bits ftr_id_isar5[] = {
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_id_mmfr4[] = {
+static const struct arm64_ftr_bits ftr_id_mmfr4[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 8, 24, 0),	/* RAZ */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 4, 4, 0),		/* ac2 */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 0, 4, 0),		/* RAZ */
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_id_pfr0[] = {
+static const struct arm64_ftr_bits ftr_id_pfr0[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 16, 16, 0),	/* RAZ */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 12, 4, 0),	/* State3 */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 8, 4, 0),		/* State2 */
@@ -220,7 +220,7 @@ static struct arm64_ftr_bits ftr_id_pfr0[] = {
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_id_dfr0[] = {
+static const struct arm64_ftr_bits ftr_id_dfr0[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
 	S_ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0xf),	/* PerfMon */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, 20, 4, 0),
@@ -238,7 +238,7 @@ static struct arm64_ftr_bits ftr_id_dfr0[] = {
  * 0. Covers the following 32bit registers:
  * id_isar[0-4], id_mmfr[1-3], id_pfr1, mvfr[0-1]
  */
-static struct arm64_ftr_bits ftr_generic_32bits[] = {
+static const struct arm64_ftr_bits ftr_generic_32bits[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0),
 	ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, 20, 4, 0),
@@ -250,17 +250,17 @@ static struct arm64_ftr_bits ftr_generic_32bits[] = {
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_generic[] = {
+static const struct arm64_ftr_bits ftr_generic[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 0, 64, 0),
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_generic32[] = {
+static const struct arm64_ftr_bits ftr_generic32[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 0, 32, 0),
 	ARM64_FTR_END,
 };
 
-static struct arm64_ftr_bits ftr_aa64raz[] = {
+static const struct arm64_ftr_bits ftr_aa64raz[] = {
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 0, 64, 0),
 	ARM64_FTR_END,
 };
@@ -346,7 +346,8 @@ static struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id)
 			search_cmp_ftr_reg);
 }
 
-static u64 arm64_ftr_set_value(struct arm64_ftr_bits *ftrp, s64 reg, s64 ftr_val)
+static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg,
+			       s64 ftr_val)
 {
 	u64 mask = arm64_ftr_mask(ftrp);
 
@@ -355,7 +356,8 @@ static u64 arm64_ftr_set_value(struct arm64_ftr_bits *ftrp, s64 reg, s64 ftr_val
 	return reg;
 }
 
-static s64 arm64_ftr_safe_value(struct arm64_ftr_bits *ftrp, s64 new, s64 cur)
+static s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
+				s64 cur)
 {
 	s64 ret = 0;
 
@@ -407,7 +409,7 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new)
 {
 	u64 val = 0;
 	u64 strict_mask = ~0x0ULL;
-	struct arm64_ftr_bits *ftrp;
+	const struct arm64_ftr_bits *ftrp;
 	struct arm64_ftr_reg *reg = get_arm64_ftr_reg(sys_reg);
 
 	BUG_ON(!reg);
@@ -464,7 +466,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
 
 static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new)
 {
-	struct arm64_ftr_bits *ftrp;
+	const struct arm64_ftr_bits *ftrp;
 
 	for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) {
 		s64 ftr_cur = arm64_ftr_value(ftrp, reg->sys_val);
-- 
2.7.4

[PATCH v2 2/3] arm64: cpufeature: constify arm64_ftr_regs array

[Ard Biesheuvel]

Constify the arm64_ftr_regs array, by moving the mutable arm64_ftr_reg
fields out of the array itself. This also streamlines the bsearch, since
the entire array can be covered by fewer cachelines. Moving the payload
out of the array also allows us to have special explicitly defined
struct instance in case other code needs to refer to it directly.

Note that this replaces the runtime sorting of the array with a runtime
BUG() check whether the array is sorted correctly in the code.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm64/include/asm/cpufeature.h |  1 -
 arch/arm64/kernel/cpufeature.c      | 46 +++++++++-----------
 2 files changed, 20 insertions(+), 27 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 7c0b7cff17df..8bb4f1527b26 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -72,7 +72,6 @@ struct arm64_ftr_bits {
  * @sys_val		Safe value across the CPUs (system view)
  */
 struct arm64_ftr_reg {
-	u32				sys_id;
 	const char			*name;
 	u64				strict_mask;
 	u64				sys_val;
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index eac76cb3a206..cc7451a27d94 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -265,14 +265,17 @@ static const struct arm64_ftr_bits ftr_aa64raz[] = {
 	ARM64_FTR_END,
 };
 
-#define ARM64_FTR_REG(id, table)		\
-	{					\
-		.sys_id = id,			\
+#define ARM64_FTR_REG(id, table) {		\
+	.sys_id = id,				\
+	.reg = 	&(struct arm64_ftr_reg){	\
 		.name = #id,			\
 		.ftr_bits = &((table)[0]),	\
-	}
+	}}
 
-static struct arm64_ftr_reg arm64_ftr_regs[] = {
+static const struct __ftr_reg_entry {
+	u32			sys_id;
+	struct arm64_ftr_reg 	*reg;
+} arm64_ftr_regs[] = {
 
 	/* Op1 = 0, CRn = 0, CRm = 1 */
 	ARM64_FTR_REG(SYS_ID_PFR0_EL1, ftr_id_pfr0),
@@ -324,7 +327,7 @@ static struct arm64_ftr_reg arm64_ftr_regs[] = {
 
 static int search_cmp_ftr_reg(const void *id, const void *regp)
 {
-	return (int)(unsigned long)id - (int)((const struct arm64_ftr_reg *)regp)->sys_id;
+	return (int)(unsigned long)id - (int)((const struct __ftr_reg_entry *)regp)->sys_id;
 }
 
 /*
@@ -339,11 +342,16 @@ static int search_cmp_ftr_reg(const void *id, const void *regp)
  */
 static struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id)
 {
-	return bsearch((const void *)(unsigned long)sys_id,
+	const struct __ftr_reg_entry *ret;
+
+	ret = bsearch((const void *)(unsigned long)sys_id,
 			arm64_ftr_regs,
 			ARRAY_SIZE(arm64_ftr_regs),
 			sizeof(arm64_ftr_regs[0]),
 			search_cmp_ftr_reg);
+	if (ret)
+		return ret->reg;
+	return NULL;
 }
 
 static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg,
@@ -378,27 +386,13 @@ static s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
 	return ret;
 }
 
-static int __init sort_cmp_ftr_regs(const void *a, const void *b)
-{
-	return ((const struct arm64_ftr_reg *)a)->sys_id -
-		 ((const struct arm64_ftr_reg *)b)->sys_id;
-}
-
-static void __init swap_ftr_regs(void *a, void *b, int size)
-{
-	struct arm64_ftr_reg tmp = *(struct arm64_ftr_reg *)a;
-	*(struct arm64_ftr_reg *)a = *(struct arm64_ftr_reg *)b;
-	*(struct arm64_ftr_reg *)b = tmp;
-}
-
 static void __init sort_ftr_regs(void)
 {
-	/* Keep the array sorted so that we can do the binary search */
-	sort(arm64_ftr_regs,
-		ARRAY_SIZE(arm64_ftr_regs),
-		sizeof(arm64_ftr_regs[0]),
-		sort_cmp_ftr_regs,
-		swap_ftr_regs);
+	int i;
+
+	/* Check that the array is sorted so that we can do the binary search */
+	for (i = 1; i < ARRAY_SIZE(arm64_ftr_regs); i++)
+		BUG_ON(arm64_ftr_regs[i].sys_id < arm64_ftr_regs[i - 1].sys_id);
 }
 
 /*
-- 
2.7.4

[PATCH v2 3/3] arm64: cpufeature: expose arm64_ftr_reg struct for CTR_EL0

[Ard Biesheuvel]

Expose the arm64_ftr_reg struct covering CTR_EL0 outside of cpufeature.o
so that other code can refer to it directly (i.e., without performing the
binary search)

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm64/include/asm/cpufeature.h | 2 ++
 arch/arm64/kernel/cpufeature.c      | 7 ++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 8bb4f1527b26..c07c5d1cd04a 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -78,6 +78,8 @@ struct arm64_ftr_reg {
 	const struct arm64_ftr_bits	*ftr_bits;
 };
 
+extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0;
+
 /* scope of capability check */
 enum {
 	SCOPE_SYSTEM,
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index cc7451a27d94..c3d7ae48f92d 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -155,6 +155,11 @@ static const struct arm64_ftr_bits ftr_ctr[] = {
 	ARM64_FTR_END,
 };
 
+struct arm64_ftr_reg arm64_ftr_reg_ctrel0 = {
+	.name		= "SYS_CTR_EL0",
+	.ftr_bits	= ftr_ctr
+};
+
 static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
 	S_ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 28, 4, 0xf),	/* InnerShr */
 	ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 24, 4, 0),	/* FCSE */
@@ -318,7 +323,7 @@ static const struct __ftr_reg_entry {
 	ARM64_FTR_REG(SYS_ID_AA64MMFR2_EL1, ftr_id_aa64mmfr2),
 
 	/* Op1 = 3, CRn = 0, CRm = 0 */
-	ARM64_FTR_REG(SYS_CTR_EL0, ftr_ctr),
+	{ SYS_CTR_EL0, &arm64_ftr_reg_ctrel0 },
 	ARM64_FTR_REG(SYS_DCZID_EL0, ftr_dczid),
 
 	/* Op1 = 3, CRn = 14, CRm = 0 */
-- 
2.7.4