target/arm: Implement ID_AA64PFR2_EL1

Currently we define the ID_AA64PFR2_EL1 encoding as reserved (with
the required RAZ behaviour for unassigned system registers in the ID
register encoding space).  Newer architecture versions start to
define fields in this ID register, so define the appropriate
constants and implement it as an ID register backed by a field in
cpu->isar.  Since none of our CPUs set that isar field to non-zero,
there is no behavioural change here (other than the name exposed to
the user via the gdbstub), but this paves the way for implementing
the new features that use fields in this register.

The fields here are the ones documented in rev L.b of the Arm ARM.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

Author: pm215

target/arm/cpu-features.h

@@ -277,6 +277,11 @@ FIELD(ID_AA64PFR1, MTEX, 52, 4)
 FIELD(ID_AA64PFR1, DF2, 56, 4)
 FIELD(ID_AA64PFR1, PFAR, 60, 4)
 
+FIELD(ID_AA64PFR2, MTEPERM, 0, 4)
+FIELD(ID_AA64PFR2, MTESTOREONLY, 4, 4)
+FIELD(ID_AA64PFR2, MTEFAR, 8, 4)
+FIELD(ID_AA64PFR2, FPMR, 32, 4)
+
 FIELD(ID_AA64MMFR0, PARANGE, 0, 4)
 FIELD(ID_AA64MMFR0, ASIDBITS, 4, 4)
 FIELD(ID_AA64MMFR0, BIGEND, 8, 4)

target/arm/cpu-sysregs.h.inc

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 DEF(ID_AA64PFR0_EL1, 3, 0, 0, 4, 0)
 DEF(ID_AA64PFR1_EL1, 3, 0, 0, 4, 1)
+DEF(ID_AA64PFR2_EL1, 3, 0, 0, 4, 2)
 DEF(ID_AA64SMFR0_EL1, 3, 0, 0, 4, 5)
 DEF(ID_AA64DFR0_EL1, 3, 0, 0, 5, 0)
 DEF(ID_AA64DFR1_EL1, 3, 0, 0, 5, 1)

target/arm/helper.c

@@ -6109,11 +6109,11 @@ void register_cp_regs_for_features(ARMCPU *cpu)
               .access = PL1_R, .type = ARM_CP_CONST,
               .accessfn = access_aa64_tid3,
               .resetvalue = GET_IDREG(isar, ID_AA64PFR1)},
-            { .name = "ID_AA64PFR2_EL1_RESERVED", .state = ARM_CP_STATE_AA64,
+            { .name = "ID_AA64PFR2_EL1", .state = ARM_CP_STATE_AA64,
               .opc0 = 3, .opc1 = 0, .crn = 0, .crm = 4, .opc2 = 2,
               .access = PL1_R, .type = ARM_CP_CONST,
               .accessfn = access_aa64_tid3,
-              .resetvalue = 0 },
+              .resetvalue = GET_IDREG(isar, ID_AA64PFR2)},
             { .name = "ID_AA64PFR3_EL1_RESERVED", .state = ARM_CP_STATE_AA64,
               .opc0 = 3, .opc1 = 0, .crn = 0, .crm = 4, .opc2 = 3,
               .access = PL1_R, .type = ARM_CP_CONST,
@@ -6341,6 +6341,8 @@ void register_cp_regs_for_features(ARMCPU *cpu)
                                R_ID_AA64PFR1_SSBS_MASK |
                                R_ID_AA64PFR1_MTE_MASK |
                                R_ID_AA64PFR1_SME_MASK },
+            { .name = "ID_AA64PFR2_EL1",
+              .exported_bits = 0 },
             { .name = "ID_AA64PFR*_EL1_RESERVED",
               .is_glob = true },
             { .name = "ID_AA64ZFR0_EL1",

target/arm/hvf/hvf.c

@@ -744,6 +744,7 @@ static bool hvf_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
     } regs[] = {
         { HV_SYS_REG_ID_AA64PFR0_EL1, &host_isar.idregs[ID_AA64PFR0_EL1_IDX] },
         { HV_SYS_REG_ID_AA64PFR1_EL1, &host_isar.idregs[ID_AA64PFR1_EL1_IDX] },
+        /* Add ID_AA64PFR2_EL1 here when HVF supports it */
         { HV_SYS_REG_ID_AA64DFR0_EL1, &host_isar.idregs[ID_AA64DFR0_EL1_IDX] },
         { HV_SYS_REG_ID_AA64DFR1_EL1, &host_isar.idregs[ID_AA64DFR1_EL1_IDX] },
         { HV_SYS_REG_ID_AA64ISAR0_EL1, &host_isar.idregs[ID_AA64ISAR0_EL1_IDX] },

target/arm/hvf/sysreg.c.inc

@@ -92,6 +92,7 @@ DEF_SYSREG(HV_SYS_REG_ID_AA64PFR0_EL1, 3, 0, 0, 4, 0)
 #endif
 
 DEF_SYSREG(HV_SYS_REG_ID_AA64PFR1_EL1, 3, 0, 0, 4, 1)
+/* Add ID_AA64PFR2_EL1 here when HVF supports it */
 DEF_SYSREG(HV_SYS_REG_ID_AA64DFR0_EL1, 3, 0, 0, 5, 0)
 DEF_SYSREG(HV_SYS_REG_ID_AA64DFR1_EL1, 3, 0, 0, 5, 1)
 DEF_SYSREG(HV_SYS_REG_ID_AA64ISAR0_EL1, 3, 0, 0, 6, 0)

target/arm/kvm.c

@@ -324,6 +324,7 @@ static bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
         err = 0;
     } else {
         err |= get_host_cpu_reg(fd, ahcf, ID_AA64PFR1_EL1_IDX);
+        err |= get_host_cpu_reg(fd, ahcf, ID_AA64PFR2_EL1_IDX);
         err |= get_host_cpu_reg(fd, ahcf, ID_AA64SMFR0_EL1_IDX);
         err |= get_host_cpu_reg(fd, ahcf, ID_AA64DFR0_EL1_IDX);
         err |= get_host_cpu_reg(fd, ahcf, ID_AA64DFR1_EL1_IDX);