arm64: sanity checks: add missing AArch32 registers

We don't currently check a number of registers exposed to AArch32 guests
(MVFR{0,1,2}_EL1 and ID_DFR0_EL1), despite the fact these describe
AArch32 feature support exposed to userspace and KVM guests similarly to
AArch64 registers which we do check. We do not expect these registers to
vary across a set of CPUs.

This patch adds said registers to the cpuinfo framework and sanity
checks. No sanity check failures have been observed on a current ARMv8
big.LITTLE platform (Juno).

Cc: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/include/asm/cpu.h

@@ -39,6 +39,7 @@ struct cpuinfo_arm64 {
 	u64		reg_id_aa64pfr0;
 	u64		reg_id_aa64pfr1;
 
+	u32		reg_id_dfr0;
 	u32		reg_id_isar0;
 	u32		reg_id_isar1;
 	u32		reg_id_isar2;
@@ -51,6 +52,10 @@ struct cpuinfo_arm64 {
 	u32		reg_id_mmfr3;
 	u32		reg_id_pfr0;
 	u32		reg_id_pfr1;
+
+	u32		reg_mvfr0;
+	u32		reg_mvfr1;
+	u32		reg_mvfr2;
 };
 
 DECLARE_PER_CPU(struct cpuinfo_arm64, cpu_data);

arch/arm64/kernel/cpuinfo.c

@@ -147,6 +147,7 @@ static void cpuinfo_sanity_check(struct cpuinfo_arm64 *cur)
 	 * If we have AArch32, we care about 32-bit features for compat. These
 	 * registers should be RES0 otherwise.
 	 */
+	diff |= CHECK(id_dfr0, boot, cur, cpu);
 	diff |= CHECK(id_isar0, boot, cur, cpu);
 	diff |= CHECK(id_isar1, boot, cur, cpu);
 	diff |= CHECK(id_isar2, boot, cur, cpu);
@@ -165,6 +166,10 @@ static void cpuinfo_sanity_check(struct cpuinfo_arm64 *cur)
 	diff |= CHECK(id_pfr0, boot, cur, cpu);
 	diff |= CHECK(id_pfr1, boot, cur, cpu);
 
+	diff |= CHECK(mvfr0, boot, cur, cpu);
+	diff |= CHECK(mvfr1, boot, cur, cpu);
+	diff |= CHECK(mvfr2, boot, cur, cpu);
+
 	/*
 	 * Mismatched CPU features are a recipe for disaster. Don't even
 	 * pretend to support them.
@@ -189,6 +194,7 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
 	info->reg_id_aa64pfr0 = read_cpuid(ID_AA64PFR0_EL1);
 	info->reg_id_aa64pfr1 = read_cpuid(ID_AA64PFR1_EL1);
 
+	info->reg_id_dfr0 = read_cpuid(ID_DFR0_EL1);
 	info->reg_id_isar0 = read_cpuid(ID_ISAR0_EL1);
 	info->reg_id_isar1 = read_cpuid(ID_ISAR1_EL1);
 	info->reg_id_isar2 = read_cpuid(ID_ISAR2_EL1);
@@ -202,6 +208,10 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
 	info->reg_id_pfr0 = read_cpuid(ID_PFR0_EL1);
 	info->reg_id_pfr1 = read_cpuid(ID_PFR1_EL1);
 
+	info->reg_mvfr0 = read_cpuid(MVFR0_EL1);
+	info->reg_mvfr1 = read_cpuid(MVFR1_EL1);
+	info->reg_mvfr2 = read_cpuid(MVFR2_EL1);
+
 	cpuinfo_detect_icache_policy(info);
 
 	check_local_cpu_errata();