target/arm: mark the 32bit alias of PAR when LPAE enabled

We also mark it ARM_CP_NO_GDB so we avoid duplicate PAR's in the
system register XML we send to gdb.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20231107105145.2916124-1-alex.bennee@linaro.org>

target/arm/helper.c

@@ -3722,20 +3722,6 @@ static void ats_write64(CPUARMState *env, const ARMCPRegInfo *ri,
 }
 #endif
 
-static const ARMCPRegInfo vapa_cp_reginfo[] = {
-    { .name = "PAR", .cp = 15, .crn = 7, .crm = 4, .opc1 = 0, .opc2 = 0,
-      .access = PL1_RW, .resetvalue = 0,
-      .bank_fieldoffsets = { offsetoflow32(CPUARMState, cp15.par_s),
-                             offsetoflow32(CPUARMState, cp15.par_ns) },
-      .writefn = par_write },
-#ifndef CONFIG_USER_ONLY
-    /* This underdecoding is safe because the reginfo is NO_RAW. */
-    { .name = "ATS", .cp = 15, .crn = 7, .crm = 8, .opc1 = 0, .opc2 = CP_ANY,
-      .access = PL1_W, .accessfn = ats_access,
-      .writefn = ats_write, .type = ARM_CP_NO_RAW | ARM_CP_RAISES_EXC },
-#endif
-};
-
 /* Return basic MPU access permission bits.  */
 static uint32_t simple_mpu_ap_bits(uint32_t val)
 {
@@ -8904,6 +8890,27 @@ void register_cp_regs_for_features(ARMCPU *cpu)
         define_arm_cp_regs(cpu, generic_timer_cp_reginfo);
     }
     if (arm_feature(env, ARM_FEATURE_VAPA)) {
+        ARMCPRegInfo vapa_cp_reginfo[] = {
+            { .name = "PAR", .cp = 15, .crn = 7, .crm = 4, .opc1 = 0, .opc2 = 0,
+              .access = PL1_RW, .resetvalue = 0,
+              .bank_fieldoffsets = { offsetoflow32(CPUARMState, cp15.par_s),
+                                     offsetoflow32(CPUARMState, cp15.par_ns) },
+              .writefn = par_write},
+#ifndef CONFIG_USER_ONLY
+            /* This underdecoding is safe because the reginfo is NO_RAW. */
+            { .name = "ATS", .cp = 15, .crn = 7, .crm = 8, .opc1 = 0, .opc2 = CP_ANY,
+              .access = PL1_W, .accessfn = ats_access,
+              .writefn = ats_write, .type = ARM_CP_NO_RAW | ARM_CP_RAISES_EXC },
+#endif
+        };
+
+        /*
+         * When LPAE exists this 32-bit PAR register is an alias of the
+         * 64-bit AArch32 PAR register defined in lpae_cp_reginfo[]
+         */
+        if (arm_feature(env, ARM_FEATURE_LPAE)) {
+            vapa_cp_reginfo[0].type = ARM_CP_ALIAS | ARM_CP_NO_GDB;
+        }
         define_arm_cp_regs(cpu, vapa_cp_reginfo);
     }
     if (arm_feature(env, ARM_FEATURE_CACHE_TEST_CLEAN)) {