Commit 256f2d4b authored by Paul Mackerras's avatar Paul Mackerras Committed by Benjamin Herrenschmidt
Browse files

powerpc: Use ibm, chip-id property to compute cpu_core_mask if available 



Some systems have an ibm,chip-id property in the cpu nodes in the
device tree.  On these systems, we now use that to compute the
cpu_core_mask (i.e. the set of core siblings) rather than looking
at cache properties.

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Tested-by: default avatarVasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent a8a5356c

arch/powerpc/kernel/smp.c

+45 −3
Original line number Diff line number Diff line
@@ -609,6 +609,33 @@ int cpu_first_thread_of_core(int core) 
}

EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);



static void traverse_siblings_chip_id(int cpu, bool add, int chipid)

{

	const struct cpumask *mask;

	struct device_node *np;

	int i, plen;

	const __be32 *prop;



	mask = add ? cpu_online_mask : cpu_present_mask;

	for_each_cpu(i, mask) {

		np = of_get_cpu_node(i, NULL);

		if (!np)

			continue;

		prop = of_get_property(np, "ibm,chip-id", &plen);

		if (prop && plen == sizeof(int) &&

		    of_read_number(prop, 1) == chipid) {

			if (add) {

				cpumask_set_cpu(cpu, cpu_core_mask(i));

				cpumask_set_cpu(i, cpu_core_mask(cpu));

			} else {

				cpumask_clear_cpu(cpu, cpu_core_mask(i));

				cpumask_clear_cpu(i, cpu_core_mask(cpu));

			}

		}

		of_node_put(np);

	}

}



/* Must be called when no change can occur to cpu_present_mask,

 * i.e. during cpu online or offline.

 */
@@ -633,14 +660,29 @@ static struct device_node *cpu_to_l2cache(int cpu) 


static void traverse_core_siblings(int cpu, bool add)

{

	struct device_node *l2_cache;

	struct device_node *l2_cache, *np;

	const struct cpumask *mask;

	int i;

	int i, chip, plen;

	const __be32 *prop;



	/* First see if we have ibm,chip-id properties in cpu nodes */

	np = of_get_cpu_node(cpu, NULL);

	if (np) {

		chip = -1;

		prop = of_get_property(np, "ibm,chip-id", &plen);

		if (prop && plen == sizeof(int))

			chip = of_read_number(prop, 1);

		of_node_put(np);

		if (chip >= 0) {

			traverse_siblings_chip_id(cpu, add, chip);

			return;

		}

	}



	l2_cache = cpu_to_l2cache(cpu);

	mask = add ? cpu_online_mask : cpu_present_mask;

	for_each_cpu(i, mask) {

		struct device_node *np = cpu_to_l2cache(i);

		np = cpu_to_l2cache(i);

		if (!np)

			continue;

		if (np == l2_cache) {

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