arm64: kernel: make the pen of the secondary a 64-bit unsigned value

Change the prototype of write_pen_release() accordingly and clarify
that's holding the hardware id of the secondary that's going to boot.
This is in preparation of getting HWIDs parsed from the DT.

Signed-off-by: Javi Merino <javi.merino@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/include/asm/cputype.h

@@ -26,6 +26,8 @@
 #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));			\

arch/arm64/kernel/smp.c

@@ -53,7 +53,7 @@
  * 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,
@@ -70,7 +70,7 @@ static DEFINE_RAW_SPINLOCK(boot_lock);
  * 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);
@@ -105,7 +105,7 @@ static int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
 
 	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);
 	}
@@ -116,7 +116,7 @@ static int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
 	 */
 	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);
@@ -190,7 +190,7 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
 	 * 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.