arm64: Rename cpuid_feature field extract routines

BugLink: https://bugs.launchpad.net/bugs/1848780

commit 28c5dcb2 upstream

Now that we have a clear understanding of the sign of a feature,
rename the routines to reflect the sign, so that it is not misused.
The cpuid_feature_extract_field() now accepts a 'sign' parameter.

This makes sure that the arm64_ftr_value() extracts the feature
field properly for signed fields.

Cc: stable@vger.kernel.org # v4.4
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

arch/arm64/include/asm/cpufeature.h

@@ -122,15 +122,15 @@ static inline void cpus_set_cap(unsigned int num)
 }
 
 static inline int __attribute_const__
-cpuid_feature_extract_field_width(u64 features, int field, int width)
+cpuid_feature_extract_signed_field_width(u64 features, int field, int width)
 {
 	return (s64)(features << (64 - width - field)) >> (64 - width);
 }
 
 static inline int __attribute_const__
-cpuid_feature_extract_field(u64 features, int field)
+cpuid_feature_extract_signed_field(u64 features, int field)
 {
-	return cpuid_feature_extract_field_width(features, field, 4);
+	return cpuid_feature_extract_signed_field_width(features, field, 4);
 }
 
 static inline unsigned int __attribute_const__
@@ -150,17 +150,23 @@ static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp)
 	return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
 }
 
+static inline int __attribute_const__
+cpuid_feature_extract_field(u64 features, int field, bool sign)
+{
+	return (sign) ?
+		cpuid_feature_extract_signed_field(features, field) :
+		cpuid_feature_extract_unsigned_field(features, field);
+}
+
 static inline s64 arm64_ftr_value(struct arm64_ftr_bits *ftrp, u64 val)
 {
-	return ftrp->sign ?
-		cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width) :
-		cpuid_feature_extract_unsigned_field_width(val, ftrp->shift, ftrp->width);
+	return (s64)cpuid_feature_extract_field(val, ftrp->shift, ftrp->sign);
 }
 
 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
 {
-	return cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
-		cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
+	return cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
+		cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
 }
 
 void __init setup_cpu_features(void);

arch/arm64/kernel/cpufeature.c

@@ -600,7 +600,7 @@ u64 read_system_reg(u32 id)
 static bool
 feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry)
 {
-	int val = cpuid_feature_extract_field(reg, entry->field_pos);
+	int val = cpuid_feature_extract_field(reg, entry->field_pos, entry->sign);
 
 	return val >= entry->min_field_value;
 }

arch/arm64/kernel/debug-monitors.c

@@ -34,7 +34,7 @@
 /* Determine debug architecture. */
 u8 debug_monitors_arch(void)
 {
-	return cpuid_feature_extract_field(read_system_reg(SYS_ID_AA64DFR0_EL1),
+	return cpuid_feature_extract_unsigned_field(read_system_reg(SYS_ID_AA64DFR0_EL1),
 						ID_AA64DFR0_DEBUGVER_SHIFT);
 }
 

arch/arm64/kvm/sys_regs.c

@@ -687,7 +687,7 @@ static bool trap_dbgidr(struct kvm_vcpu *vcpu,
 	} else {
 		u64 dfr = read_system_reg(SYS_ID_AA64DFR0_EL1);
 		u64 pfr = read_system_reg(SYS_ID_AA64PFR0_EL1);
-		u32 el3 = !!cpuid_feature_extract_field(pfr, ID_AA64PFR0_EL3_SHIFT);
+		u32 el3 = !!cpuid_feature_extract_unsigned_field(pfr, ID_AA64PFR0_EL3_SHIFT);
 
 		p->regval = ((((dfr >> ID_AA64DFR0_WRPS_SHIFT) & 0xf) << 28) |
 			     (((dfr >> ID_AA64DFR0_BRPS_SHIFT) & 0xf) << 24) |

arch/arm64/mm/context.c

@@ -187,7 +187,8 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu)
 
 static int asids_init(void)
 {
-	int fld = cpuid_feature_extract_field(read_cpuid(ID_AA64MMFR0_EL1), 4);
+	int fld = cpuid_feature_extract_unsigned_field(read_cpuid(ID_AA64MMFR0_EL1),
+						       ID_AA64MMFR0_ASID_SHIFT);
 
 	switch (fld) {
 	default: