target-arm: Don't expose wildcard ID register definitions for ARMv8

In ARMv8 the 32 bit coprocessor ID register space is tidied up to
remove the wildcarded aliases of the MIDR and the RAZ behaviour
for the unassigned space where crm = 3..7. Make sure we don't
expose thes wildcards for v8 cores. This means we need to have
a specific implementation for REVIDR, an IMPDEF register which
may be the same as the MIDR (and which we always implement as such).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>

1 files changed, 43 insertions, 18 deletions

diff --git a/target-arm/helper.c b/target-arm/helper.c
index 825c8c99eb..8706407b32 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -2258,8 +2258,9 @@ void register_cp_regs_for_features(ARMCPU *cpu)
      * be read-only (ie write causes UNDEF exception).
      */
     {
-        ARMCPRegInfo id_cp_reginfo[] = {
-            /* Note that the MIDR isn't a simple constant register because
+        ARMCPRegInfo id_pre_v8_midr_cp_reginfo[] = {
+            /* Pre-v8 MIDR space.
+             * Note that the MIDR isn't a simple constant register because
              * of the TI925 behaviour where writes to another register can
              * cause the MIDR value to change.
              *
@@ -2273,22 +2274,6 @@ void register_cp_regs_for_features(ARMCPU *cpu)
               .writefn = arm_cp_write_ignore, .raw_writefn = raw_write,
               .fieldoffset = offsetof(CPUARMState, cp15.c0_cpuid),
               .type = ARM_CP_OVERRIDE },
-            { .name = "MIDR_EL1", .state = ARM_CP_STATE_AA64,
-              .opc0 = 3, .opc1 = 0, .opc2 = 0, .crn = 0, .crm = 0,
-              .access = PL1_R, .resetvalue = cpu->midr, .type = ARM_CP_CONST },
-            { .name = "CTR",
-              .cp = 15, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 1,
-              .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = cpu->ctr },
-            { .name = "CTR_EL0", .state = ARM_CP_STATE_AA64,
-              .opc0 = 3, .opc1 = 3, .opc2 = 1, .crn = 0, .crm = 0,
-              .access = PL0_R, .accessfn = ctr_el0_access,
-              .type = ARM_CP_CONST, .resetvalue = cpu->ctr },
-            { .name = "TCMTR",
-              .cp = 15, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 2,
-              .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = 0 },
-            { .name = "TLBTR",
-              .cp = 15, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 3,
-              .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = 0 },
             /* crn = 0 op1 = 0 crm = 3..7 : currently unassigned; we RAZ. */
             { .name = "DUMMY",
               .cp = 15, .crn = 0, .crm = 3, .opc1 = 0, .opc2 = CP_ANY,
@@ -2307,6 +2292,37 @@ void register_cp_regs_for_features(ARMCPU *cpu)
               .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = 0 },
             REGINFO_SENTINEL
         };
+        ARMCPRegInfo id_v8_midr_cp_reginfo[] = {
+            /* v8 MIDR -- the wildcard isn't necessary, and nor is the
+             * variable-MIDR TI925 behaviour. Instead we have a single
+             * (strictly speaking IMPDEF) alias of the MIDR, REVIDR.
+             */
+            { .name = "MIDR_EL1", .state = ARM_CP_STATE_BOTH,
+              .opc0 = 3, .opc1 = 0, .crn = 0, .crm = 0, .opc2 = 0,
+              .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = cpu->midr },
+            { .name = "REVIDR_EL1", .state = ARM_CP_STATE_BOTH,
+              .opc0 = 3, .opc1 = 0, .crn = 0, .crm = 0, .opc2 = 6,
+              .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = cpu->midr },
+            REGINFO_SENTINEL
+        };
+        ARMCPRegInfo id_cp_reginfo[] = {
+            /* These are common to v8 and pre-v8 */
+            { .name = "CTR",
+              .cp = 15, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 1,
+              .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = cpu->ctr },
+            { .name = "CTR_EL0", .state = ARM_CP_STATE_AA64,
+              .opc0 = 3, .opc1 = 3, .opc2 = 1, .crn = 0, .crm = 0,
+              .access = PL0_R, .accessfn = ctr_el0_access,
+              .type = ARM_CP_CONST, .resetvalue = cpu->ctr },
+            /* TCMTR and TLBTR exist in v8 but have no 64-bit versions */
+            { .name = "TCMTR",
+              .cp = 15, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 2,
+              .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = 0 },
+            { .name = "TLBTR",
+              .cp = 15, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 3,
+              .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = 0 },
+            REGINFO_SENTINEL
+        };
         ARMCPRegInfo crn0_wi_reginfo = {
             .name = "CRN0_WI", .cp = 15, .crn = 0, .crm = CP_ANY,
             .opc1 = CP_ANY, .opc2 = CP_ANY, .access = PL1_W,
@@ -2321,10 +2337,19 @@ void register_cp_regs_for_features(ARMCPU *cpu)
              * UNDEF.
              */
             define_one_arm_cp_reg(cpu, &crn0_wi_reginfo);
+            for (r = id_pre_v8_midr_cp_reginfo;
+                 r->type != ARM_CP_SENTINEL; r++) {
+                r->access = PL1_RW;
+            }
             for (r = id_cp_reginfo; r->type != ARM_CP_SENTINEL; r++) {
                 r->access = PL1_RW;
             }
         }
+        if (arm_feature(env, ARM_FEATURE_V8)) {
+            define_arm_cp_regs(cpu, id_v8_midr_cp_reginfo);
+        } else {
+            define_arm_cp_regs(cpu, id_pre_v8_midr_cp_reginfo);
+        }
         define_arm_cp_regs(cpu, id_cp_reginfo);
     }