[PATCH v1 03/12] arm64/cpufeature: Add system-wide FEAT_HACDBS detection

[Leonardo Bras]

FEAT_HACDBS will only be used for dirty-bit cleaning if it is detected in
all running cpus.

Signed-off-by: Leonardo Bras <leo.bras at arm.com>
---
 arch/arm64/include/asm/cpufeature.h | 5 +++++
 arch/arm64/kernel/cpufeature.c      | 8 ++++++++
 arch/arm64/tools/cpucaps            | 1 +
 3 files changed, 14 insertions(+)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index dcc2e2cad5ad..5d438a00e0ff 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -854,20 +854,25 @@ static inline bool system_supports_gcs(void)
 static inline bool system_supports_haft(void)
 {
 	return cpus_have_final_cap(ARM64_HAFT);
 }
 
 static inline bool system_supports_hdbss(void)
 {
 	return cpus_have_final_cap(ARM64_HAS_HDBSS);
 }
 
+static inline bool system_supports_hacdbs(void)
+{
+	return cpus_have_final_cap(ARM64_HACDBS);
+}
+
 static __always_inline bool system_supports_mpam(void)
 {
 	return alternative_has_cap_unlikely(ARM64_MPAM);
 }
 
 static __always_inline bool system_supports_mpam_hcr(void)
 {
 	return alternative_has_cap_unlikely(ARM64_MPAM_HCR);
 }
 
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index eac7784463e3..95b92060cae1 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -512,20 +512,21 @@ static const struct arm64_ftr_bits ftr_id_aa64mmfr3[] = {
 		       FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR3_EL1_S1POE_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR3_EL1_S1PIE_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR3_EL1_SCTLRX_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR3_EL1_TCRX_SHIFT, 4, 0),
 	ARM64_FTR_END,
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64mmfr4[] = {
 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR4_EL1_E2H0_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR4_EL1_NV_frac_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR4_EL1_HACDBS_SHIFT, 4, 0),
 	ARM64_FTR_END,
 };
 
 static const struct arm64_ftr_bits ftr_ctr[] = {
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, 31, 1, 1), /* RES1 */
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_EL0_DIC_SHIFT, 1, 1),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_EL0_IDC_SHIFT, 1, 1),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_OR_ZERO_SAFE, CTR_EL0_CWG_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_OR_ZERO_SAFE, CTR_EL0_ERG_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_EL0_DminLine_SHIFT, 4, 1),
@@ -2752,20 +2753,27 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 	{
 		.desc = "Hardware dirty bit management",
 		.type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
 		.capability = ARM64_HW_DBM,
 		.matches = has_hw_dbm,
 		.cpu_enable = cpu_enable_hw_dbm,
 		.cpus = &dbm_cpus,
 		ARM64_CPUID_FIELDS(ID_AA64MMFR1_EL1, HAFDBS, DBM)
 	},
 #endif
+	{
+		.desc = "Hardware dirty bit Cleaning",
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.capability = ARM64_HACDBS,
+		.matches = has_cpuid_feature,
+		ARM64_CPUID_FIELDS(ID_AA64MMFR4_EL1, HACDBS, IMP)
+	},
 #ifdef CONFIG_ARM64_HAFT
 	{
 		.desc = "Hardware managed Access Flag for Table Descriptors",
 		/*
 		 * Contrary to the page/block access flag, the table access flag
 		 * cannot be emulated in software (no access fault will occur).
 		 * Therefore this should be used only if it's supported system
 		 * wide.
 		 */
 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index 6bd563e0bc62..cd53cec79d34 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -65,20 +65,21 @@ HAS_STAGE2_FWB
 HAS_TCR2
 HAS_TIDCP1
 HAS_TLB_RANGE
 HAS_VA52
 HAS_VIRT_HOST_EXTN
 HAS_WFXT
 HAS_XNX
 HAS_HDBSS
 HAFT
 HW_DBM
+HACDBS
 KVM_HVHE
 KVM_PROTECTED_MODE
 MISMATCHED_CACHE_TYPE
 MPAM
 MPAM_HCR
 MTE
 MTE_ASYMM
 MTE_FAR
 MTE_STORE_ONLY
 SME
-- 
2.54.0