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Commit 64001113 authored by Catalin Marinas's avatar Catalin Marinas
Browse files

arm64: Remove boot thread synchronisation for spin-table release method 



The synchronisation with the boot thread already happens in __cpu_up()
via wait_for_completion_timeout(). In addition, __cpu_up() calls are
protected by the cpu_add_remove_lock mutex and already serialised.

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent a41dc0e8

arch/arm64/kernel/smp_spin_table.c

+1 −38
Original line number Diff line number Diff line
@@ -30,7 +30,6 @@ extern void secondary_holding_pen(void); 
volatile unsigned long secondary_holding_pen_release = INVALID_HWID;



static phys_addr_t cpu_release_addr[NR_CPUS];

static DEFINE_RAW_SPINLOCK(boot_lock);



/*

 * Write secondary_holding_pen_release in a way that is guaranteed to be
@@ -94,14 +93,6 @@ static int smp_spin_table_cpu_prepare(unsigned int cpu) 


static int smp_spin_table_cpu_boot(unsigned int cpu)

{

	unsigned long timeout;



	/*

	 * Set synchronisation state between this boot processor

	 * and the secondary one

	 */

	raw_spin_lock(&boot_lock);



	/*

	 * Update the pen release flag.

	 */
@@ -112,34 +103,7 @@ static int smp_spin_table_cpu_boot(unsigned int cpu) 
	 */

	sev();



	timeout = jiffies + (1 * HZ);

	while (time_before(jiffies, timeout)) {

		if (secondary_holding_pen_release == INVALID_HWID)

			break;

		udelay(10);

	}



	/*

	 * Now the secondary core is starting up let it run its

	 * calibrations, then wait for it to finish

	 */

	raw_spin_unlock(&boot_lock);



	return secondary_holding_pen_release != INVALID_HWID ? -ENOSYS : 0;

}



static void smp_spin_table_cpu_postboot(void)

{

	/*

	 * Let the primary processor know we're out of the pen.

	 */

	write_pen_release(INVALID_HWID);



	/*

	 * Synchronise with the boot thread.

	 */

	raw_spin_lock(&boot_lock);

	raw_spin_unlock(&boot_lock);

	return 0;

}



const struct cpu_operations smp_spin_table_ops = {
@@ -147,5 +111,4 @@ const struct cpu_operations smp_spin_table_ops = { 
	.cpu_init	= smp_spin_table_cpu_init,

	.cpu_prepare	= smp_spin_table_cpu_prepare,

	.cpu_boot	= smp_spin_table_cpu_boot,

	.cpu_postboot	= smp_spin_table_cpu_postboot,

};