Add all FEAT_MEC registers.

To work properly, FEAT_MEC also depends on FEAT_SCTLR2 and FEAT_TCR2,
which are not implemented in this commit. The bits in SCTLR2 and TCR2
control which translation regimes use MECIDs, and determine which MECID
is selected and will be implemented in subsequent commits.

FEAT_MEC also requires two new cache management instructions, not
included in this commit, that will be implemented in a subsequent commit.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/cpu-features.h |  5 +++
 target/arm/cpu.h          |  9 +++++
 target/arm/helper.c       | 70 +++++++++++++++++++++++++++++++++++++++
 target/arm/internals.h    |  3 ++
 4 files changed, 87 insertions(+)

diff --git a/target/arm/cpu-features.h b/target/arm/cpu-features.h
index 5876162428..72b6fd9b27 100644
--- a/target/arm/cpu-features.h
+++ b/target/arm/cpu-features.h
@@ -904,6 +904,11 @@ static inline bool isar_feature_aa64_nv2(const ARMISARegisters *id)
     return FIELD_EX64_IDREG(id, ID_AA64MMFR2, NV) >= 2;
 }
 
+static inline bool isar_feature_aa64_mec(const ARMISARegisters *id)
+{
+    return FIELD_EX64_IDREG(id, ID_AA64MMFR3, MEC) != 0;
+}
+
 static inline bool isar_feature_aa64_pmuv3p1(const ARMISARegisters *id)
 {
     return FIELD_EX64_IDREG(id, ID_AA64DFR0, PMUVER) >= 4 &&
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 0f64c7b163..40ca093331 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -576,6 +576,15 @@ typedef struct CPUArchState {
 
         /* NV2 register */
         uint64_t vncr_el2;
+
+        /* MEC registers */
+        uint64_t mecid_p0_el2;
+        uint64_t mecid_a0_el2;
+        uint64_t mecid_p1_el2;
+        uint64_t mecid_a1_el2;
+        uint64_t mecid_rl_a_el3;
+        uint64_t vmecid_p_el2;
+        uint64_t vmecid_a_el2;
     } cp15;
 
     struct {
diff --git a/target/arm/helper.c b/target/arm/helper.c
index b3f0d6f17a..984406c945 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -6827,6 +6827,72 @@ static const ARMCPRegInfo nmi_reginfo[] = {
       .resetfn = arm_cp_reset_ignore },
 };
 
+static CPAccessResult mecid_access(CPUARMState *env,
+                                   const ARMCPRegInfo *ri, bool isread)
+{
+    int el = arm_current_el(env);
+
+    if (el == 2) {
+        if (arm_security_space(env) != ARMSS_Realm) {
+	    return CP_ACCESS_UNDEFINED;
+	}
+
+        if (!(env->cp15.scr_el3 & SCR_MECEN)) {
+            return CP_ACCESS_TRAP_EL3;
+        }
+    }
+
+    return CP_ACCESS_OK;
+}
+
+static void mecid_write(CPUARMState *env, const ARMCPRegInfo *ri,
+                        uint64_t value)
+{
+    value = extract64(value, 0, MECID_WIDTH);
+    raw_write(env, ri, value);
+}
+
+static const ARMCPRegInfo mec_reginfo[] = {
+    { .name = "MECIDR_EL2", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 4, .opc2 = 7, .crn = 10, .crm = 8,
+      .access = PL2_R, .type = ARM_CP_CONST, .resetvalue = MECID_WIDTH - 1 },
+    { .name = "MECID_P0_EL2", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 4, .opc2 = 0, .crn = 10, .crm = 8,
+      .access = PL2_RW, .accessfn = mecid_access,
+      .writefn = mecid_write,
+      .fieldoffset = offsetof(CPUARMState, cp15.mecid_p0_el2) },
+    { .name = "MECID_A0_EL2", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 4, .opc2 = 1, .crn = 10, .crm = 8,
+      .access = PL2_RW, .accessfn = mecid_access,
+      .writefn = mecid_write,
+      .fieldoffset = offsetof(CPUARMState, cp15.mecid_a0_el2) },
+    { .name = "MECID_P1_EL2", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 4, .opc2 = 2, .crn = 10, .crm = 8,
+      .access = PL2_RW, .accessfn = mecid_access,
+      .writefn = mecid_write,
+      .fieldoffset = offsetof(CPUARMState, cp15.mecid_p1_el2) },
+    { .name = "MECID_A1_EL2", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 4, .opc2 = 3, .crn = 10, .crm = 8,
+      .access = PL2_RW, .accessfn = mecid_access,
+      .writefn = mecid_write,
+      .fieldoffset = offsetof(CPUARMState, cp15.mecid_a1_el2) },
+    { .name = "MECID_RL_A_EL3", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 6, .opc2 = 1, .crn = 10, .crm = 10,
+      .access = PL3_RW, .accessfn = mecid_access,
+      .writefn = mecid_write,
+      .fieldoffset = offsetof(CPUARMState, cp15.mecid_rl_a_el3) },
+    { .name = "VMECID_P_EL2", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 4, .opc2 = 0, .crn = 10, .crm = 9,
+      .access = PL2_RW, .accessfn = mecid_access,
+      .writefn = mecid_write,
+      .fieldoffset = offsetof(CPUARMState, cp15.vmecid_p_el2) },
+    { .name = "VMECID_A_EL2", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 4, .opc2 = 1, .crn = 10, .crm = 9,
+      .access = PL2_RW, .accessfn = mecid_access,
+      .writefn = mecid_write,
+      .fieldoffset = offsetof(CPUARMState, cp15.vmecid_a_el2) },
+};
+
 static void define_pmu_regs(ARMCPU *cpu)
 {
     /*
@@ -9014,6 +9080,10 @@ void register_cp_regs_for_features(ARMCPU *cpu)
         define_arm_cp_regs(cpu, nmi_reginfo);
     }
 
+    if (cpu_isar_feature(aa64_mec, cpu)) {
+        define_arm_cp_regs(cpu, mec_reginfo);
+    }
+
     if (cpu_isar_feature(any_predinv, cpu)) {
         define_arm_cp_regs(cpu, predinv_reginfo);
     }
diff --git a/target/arm/internals.h b/target/arm/internals.h
index 21a8d67edd..77ba2a2273 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -1982,4 +1982,7 @@ void vfp_clear_float_status_exc_flags(CPUARMState *env);
  */
 void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask);
 
+/* Used in FEAT_MEC to set the MECIDWidthm1 field in the MECIDR_EL2 register. */
+#define MECID_WIDTH 16
+
 #endif
-- 
2.34.1