target-arm: Add arm_ccnt_enabled function

Include a helper function to determine if the CCNT counter
is enabled.
Signed-off-by: NAlistair Francis <alistair.francis@xilinx.com>
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Message-id: e1a64f17a756e06c8bda8238ad4826d705049f7a.1409025949.git.peter.crosthwaite@xilinx.com
[ PC changes
  * Remove EL based checks
]
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

target-arm/helper.c

@@ -548,6 +548,18 @@ static CPAccessResult pmreg_access(CPUARMState *env, const ARMCPRegInfo *ri)
 }
 
 #ifndef CONFIG_USER_ONLY
+
+static inline bool arm_ccnt_enabled(CPUARMState *env)
+{
+    /* This does not support checking PMCCFILTR_EL0 register */
+
+    if (!(env->cp15.c9_pmcr & PMCRE)) {
+        return false;
+    }
+
+    return true;
+}
+
 static void pmcr_write(CPUARMState *env, const ARMCPRegInfo *ri,
                        uint64_t value)
 {