target-arm: Add register_cp_regs_for_features()

Add new function register_cp_regs_for_features() as a place to
register coprocessor registers dependent on feature flags.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target-arm/cpu-qom.h

@@ -107,5 +107,6 @@ static inline ARMCPU *arm_env_get_cpu(CPUARMState *env)
 #define ENV_GET_CPU(e) CPU(arm_env_get_cpu(e))
 
 void arm_cpu_realize(ARMCPU *cpu);
+void register_cp_regs_for_features(ARMCPU *cpu);
 
 #endif

target-arm/cpu.c

@@ -216,6 +216,8 @@ void arm_cpu_realize(ARMCPU *cpu)
     if (arm_feature(env, ARM_FEATURE_VFP3)) {
         set_feature(env, ARM_FEATURE_VFP);
     }
+
+    register_cp_regs_for_features(cpu);
 }
 
 /* CPU models */

target-arm/helper.c

@@ -56,6 +56,17 @@ static int vfp_gdb_set_reg(CPUARMState *env, uint8_t *buf, int reg)
     return 0;
 }
 
+void register_cp_regs_for_features(ARMCPU *cpu)
+{
+    /* Register all the coprocessor registers based on feature bits */
+    CPUARMState *env = &cpu->env;
+    if (arm_feature(env, ARM_FEATURE_M)) {
+        /* M profile has no coprocessor registers */
+        return;
+    }
+
+}
+
 ARMCPU *cpu_arm_init(const char *cpu_model)
 {
     ARMCPU *cpu;