[PATCH v2 1/2] arm64: cpufeature: Add support for the MPAM v0.1 architecture version

[Zeng Heng <zengheng4@huawei.com>]

According to the MPAM spec [1], the supported architecture versions are
v1.0, v1.1 and v0.1. MPAM versions v0.1 and v1.1 are functionally
identical, but v0.1 additionally supports the FORCE_NS feature.

ID_AA64PR | ID_AA64PR | MPAM Extension | Notes
F0_EL1.   | F1_EL1.   | Architecture   |
MPAM      | MPAM_frac | version        |
---------------------------------------------------------------------------
0b0000    | 0b0001    | v0.1           | MPAM v0.1 is implemented.
          |           |                | MPAM v0.1 is the same as MPAM v1.1
          |           |                | with FORCE_NS which is
          |           |                | incompatible with MPAM v1.0.
---------------------------------------------------------------------------
0b0001    | 0b0000    | v1.0           | MPAM v1.0 is implemented.
---------------------------------------------------------------------------
0b0001    | 0b0001    | v1.1           | MPAM v1.1 is implemented.
          |           |                | MPAM v1.1 includes all features of
          |           |                | MPAM v1.0.
          |           |                | It must not include FORCE_NS.

FORCE_NS is a feature that operates in EL3 mode. Consequently, the current
Linux MPAM driver is also compatible with MPAM v0.1. To support v0.1, the
existing driver which only checks ID_AA64PFR0_EL1.MPAM for the major
version needs to examine ID_AA64PFR1_EL1.MPAM_frac for the minor version
as well.

[1] https://developer.arm.com/documentation/ddi0598/db/?lang=en

Signed-off-by: Zeng Heng <zengheng4@huawei.com>
---
 arch/arm64/include/asm/cpufeature.h |  7 +++++++
 arch/arm64/include/asm/el2_setup.h  |  4 +++-
 arch/arm64/kernel/cpufeature.c      | 15 +++++++++++----
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 4de51f8d92cb..a57870fa96db 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -620,6 +620,13 @@ static inline bool id_aa64pfr0_mpam(u64 pfr0)
 	return val > 0;
 }
 
+static inline bool id_aa64pfr1_mpamfrac(u64 pfr1)
+{
+	u32 val = cpuid_feature_extract_unsigned_field(pfr1, ID_AA64PFR1_EL1_MPAM_frac_SHIFT);
+
+	return val > 0;
+}
+
 static inline bool id_aa64pfr1_mte(u64 pfr1)
 {
 	u32 val = cpuid_feature_extract_unsigned_field(pfr1, ID_AA64PFR1_EL1_MTE_SHIFT);
diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
index cacd20df1786..606cf14e4044 100644
--- a/arch/arm64/include/asm/el2_setup.h
+++ b/arch/arm64/include/asm/el2_setup.h
@@ -501,7 +501,9 @@
 #endif
 
 .macro finalise_el2_state
-	check_override id_aa64pfr0, ID_AA64PFR0_EL1_MPAM_SHIFT, .Linit_mpam_\@, .Lskip_mpam_\@, x1, x2
+	check_override id_aa64pfr0, ID_AA64PFR0_EL1_MPAM_SHIFT, .Linit_mpam_\@, .Lmpam_minor_\@, x1, x2
+.Lmpam_minor_\@:
+	check_override id_aa64pfr1, ID_AA64PFR1_EL1_MPAM_frac_SHIFT, .Linit_mpam_\@, .Lskip_mpam_\@, x1, x2
 
 .Linit_mpam_\@:
 	msr_s	SYS_MPAM2_EL2, xzr		// use the default partition
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index c840a93b9ef9..e8fa6f7cf2a2 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1159,6 +1159,14 @@ static __init void detect_system_supports_pseudo_nmi(void)
 static inline void detect_system_supports_pseudo_nmi(void) { }
 #endif
 
+static bool detect_ftr_has_mpam(void)
+{
+	u64 pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
+	u64 pfr1 = read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1);
+
+	return id_aa64pfr0_mpam(pfr0) || id_aa64pfr1_mpamfrac(pfr1);
+}
+
 void __init init_cpu_features(struct cpuinfo_arm64 *info)
 {
 	/* Before we start using the tables, make sure it is sorted */
@@ -1206,7 +1214,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
 		cpacr_restore(cpacr);
 	}
 
-	if (id_aa64pfr0_mpam(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1))) {
+	if (detect_ftr_has_mpam()) {
 		info->reg_mpamidr = read_cpuid(MPAMIDR_EL1);
 		init_cpu_ftr_reg(SYS_MPAMIDR_EL1, info->reg_mpamidr);
 	}
@@ -1462,7 +1470,7 @@ void update_cpu_features(int cpu,
 		cpacr_restore(cpacr);
 	}
 
-	if (id_aa64pfr0_mpam(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1))) {
+	if (detect_ftr_has_mpam()) {
 		info->reg_mpamidr = read_cpuid(MPAMIDR_EL1);
 		taint |= check_update_ftr_reg(SYS_MPAMIDR_EL1, cpu,
 					info->reg_mpamidr, boot->reg_mpamidr);
@@ -2473,7 +2481,7 @@ cpucap_panic_on_conflict(const struct arm64_cpu_capabilities *cap)
 static bool
 test_has_mpam(const struct arm64_cpu_capabilities *entry, int scope)
 {
-	if (!has_cpuid_feature(entry, scope))
+	if (!detect_ftr_has_mpam())
 		return false;
 
 	/* Check firmware actually enabled MPAM on this cpu. */
@@ -3078,7 +3086,6 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.capability = ARM64_MPAM,
 		.matches = test_has_mpam,
 		.cpu_enable = cpu_enable_mpam,
-		ARM64_CPUID_FIELDS(ID_AA64PFR0_EL1, MPAM, 1)
 	},
 	{
 		.desc = "Memory Partitioning And Monitoring Virtualisation",
-- 
2.25.1