[PATCH V3 05/16] arm64/cpufeature: Introduce ID_DFR1 CPU register

[Anshuman Khandual <anshuman.khandual@arm.com>]

This adds basic building blocks required for ID_DFR1 CPU register which
provides top level information about the debug system in AArch32 state.
This is added per ARM DDI 0487F.a specification.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org

Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/arm64/include/asm/cpu.h    |  1 +
 arch/arm64/include/asm/sysreg.h |  3 +++
 arch/arm64/kernel/cpufeature.c  | 10 ++++++++++
 arch/arm64/kernel/cpuinfo.c     |  1 +
 arch/arm64/kvm/sys_regs.c       |  2 +-
 5 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h
index 464e828a994d..d9a78bdec409 100644
--- a/arch/arm64/include/asm/cpu.h
+++ b/arch/arm64/include/asm/cpu.h
@@ -33,6 +33,7 @@ struct cpuinfo_arm64 {
 	u64		reg_id_aa64zfr0;
 
 	u32		reg_id_dfr0;
+	u32		reg_id_dfr1;
 	u32		reg_id_isar0;
 	u32		reg_id_isar1;
 	u32		reg_id_isar2;
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index c977449e02db..2e1e922e1409 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -154,6 +154,7 @@
 #define SYS_MVFR1_EL1			sys_reg(3, 0, 0, 3, 1)
 #define SYS_MVFR2_EL1			sys_reg(3, 0, 0, 3, 2)
 #define SYS_ID_PFR2_EL1			sys_reg(3, 0, 0, 3, 4)
+#define SYS_ID_DFR1_EL1			sys_reg(3, 0, 0, 3, 5)
 
 #define SYS_ID_AA64PFR0_EL1		sys_reg(3, 0, 0, 4, 0)
 #define SYS_ID_AA64PFR1_EL1		sys_reg(3, 0, 0, 4, 1)
@@ -763,6 +764,8 @@
 #define ID_ISAR4_WITHSHIFTS_SHIFT	4
 #define ID_ISAR4_UNPRIV_SHIFT		0
 
+#define ID_DFR1_MTPMU_SHIFT		0
+
 #define ID_ISAR0_DIVIDE_SHIFT		24
 #define ID_ISAR0_DEBUG_SHIFT		20
 #define ID_ISAR0_COPROC_SHIFT		16
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index a8247bf92959..2ce952d9668d 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -451,6 +451,11 @@ static const struct arm64_ftr_bits ftr_id_dfr0[] = {
 	ARM64_FTR_END,
 };
 
+static const struct arm64_ftr_bits ftr_id_dfr1[] = {
+	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_DFR1_MTPMU_SHIFT, 4, 0),
+	ARM64_FTR_END,
+};
+
 static const struct arm64_ftr_bits ftr_zcr[] = {
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE,
 		ZCR_ELx_LEN_SHIFT, ZCR_ELx_LEN_SIZE, 0),	/* LEN */
@@ -521,6 +526,7 @@ static const struct __ftr_reg_entry {
 	ARM64_FTR_REG(SYS_MVFR1_EL1, ftr_generic_32bits),
 	ARM64_FTR_REG(SYS_MVFR2_EL1, ftr_mvfr2),
 	ARM64_FTR_REG(SYS_ID_PFR2_EL1, ftr_id_pfr2),
+	ARM64_FTR_REG(SYS_ID_DFR1_EL1, ftr_id_dfr1),
 
 	/* Op1 = 0, CRn = 0, CRm = 4 */
 	ARM64_FTR_REG(SYS_ID_AA64PFR0_EL1, ftr_id_aa64pfr0),
@@ -714,6 +720,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
 
 	if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
 		init_cpu_ftr_reg(SYS_ID_DFR0_EL1, info->reg_id_dfr0);
+		init_cpu_ftr_reg(SYS_ID_DFR1_EL1, info->reg_id_dfr1);
 		init_cpu_ftr_reg(SYS_ID_ISAR0_EL1, info->reg_id_isar0);
 		init_cpu_ftr_reg(SYS_ID_ISAR1_EL1, info->reg_id_isar1);
 		init_cpu_ftr_reg(SYS_ID_ISAR2_EL1, info->reg_id_isar2);
@@ -829,6 +836,8 @@ static int update_32bit_cpu_features(int cpu, struct cpuinfo_arm64 *info,
 
 	taint |= check_update_ftr_reg(SYS_ID_DFR0_EL1, cpu,
 				      info->reg_id_dfr0, boot->reg_id_dfr0);
+	taint |= check_update_ftr_reg(SYS_ID_DFR1_EL1, cpu,
+				      info->reg_id_dfr1, boot->reg_id_dfr1);
 	taint |= check_update_ftr_reg(SYS_ID_ISAR0_EL1, cpu,
 				      info->reg_id_isar0, boot->reg_id_isar0);
 	taint |= check_update_ftr_reg(SYS_ID_ISAR1_EL1, cpu,
@@ -992,6 +1001,7 @@ static u64 __read_sysreg_by_encoding(u32 sys_id)
 	read_sysreg_case(SYS_ID_PFR1_EL1);
 	read_sysreg_case(SYS_ID_PFR2_EL1);
 	read_sysreg_case(SYS_ID_DFR0_EL1);
+	read_sysreg_case(SYS_ID_DFR1_EL1);
 	read_sysreg_case(SYS_ID_MMFR0_EL1);
 	read_sysreg_case(SYS_ID_MMFR1_EL1);
 	read_sysreg_case(SYS_ID_MMFR2_EL1);
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index cb79b083f97f..50a281703d9d 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -362,6 +362,7 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
 	/* Update the 32bit ID registers only if AArch32 is implemented */
 	if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
 		info->reg_id_dfr0 = read_cpuid(ID_DFR0_EL1);
+		info->reg_id_dfr1 = read_cpuid(ID_DFR1_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);
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index b784b156edb3..c78aa15aaac8 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1457,7 +1457,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	ID_SANITISED(MVFR2_EL1),
 	ID_UNALLOCATED(3,3),
 	ID_SANITISED(ID_PFR2_EL1),
-	ID_UNALLOCATED(3,5),
+	ID_SANITISED(ID_DFR1_EL1),
 	ID_UNALLOCATED(3,6),
 	ID_UNALLOCATED(3,7),
 
-- 
2.20.1