#define ID_AA64ISAR0_EL1       "id_aa64isar0_el1"
 #define ID_AA64MMFR0_EL1       "id_aa64mmfr0_el1"
 
+#define INVALID_HWID           ULONG_MAX
+
 #define read_cpuid(reg) ({                                             \
        u64 __val;                                                      \
        asm("mrs        %0, " reg : "=r" (__val));                      \
 
  * where to place its SVC stack
  */
 struct secondary_data secondary_data;
-volatile unsigned long secondary_holding_pen_release = -1;
+volatile unsigned long secondary_holding_pen_release = INVALID_HWID;
 
 enum ipi_msg_type {
        IPI_RESCHEDULE,
  * in coherency or not.  This is necessary for the hotplug code to work
  * reliably.
  */
-static void __cpuinit write_pen_release(int val)
+static void __cpuinit write_pen_release(u64 val)
 {
        void *start = (void *)&secondary_holding_pen_release;
        unsigned long size = sizeof(secondary_holding_pen_release);
 
        timeout = jiffies + (1 * HZ);
        while (time_before(jiffies, timeout)) {
-               if (secondary_holding_pen_release == -1UL)
+               if (secondary_holding_pen_release == INVALID_HWID)
                        break;
                udelay(10);
        }
         */
        raw_spin_unlock(&boot_lock);
 
-       return secondary_holding_pen_release != -1 ? -ENOSYS : 0;
+       return secondary_holding_pen_release != INVALID_HWID ? -ENOSYS : 0;
 }
 
 static DECLARE_COMPLETION(cpu_running);
         * Let the primary processor know we're out of the
         * pen, then head off into the C entry point
         */
-       write_pen_release(-1);
+       write_pen_release(INVALID_HWID);
 
        /*
         * Synchronise with the boot thread.