Commit 38db9b95 authored by Sudeep Holla's avatar Sudeep Holla
Browse files

arch_topology: Add support to parse and detect cache attributes 

Currently ACPI populates just the minimum information about the last
level cache from PPTT in order to feed the same to build sched_domains.
Similar support for DT platforms is not present.

In order to enable the same, the entire cache hierarchy information can
be built as part of CPU topoplogy parsing both on ACPI and DT platforms.

Note that this change builds the cacheinfo early even on ACPI systems,
but the current mechanism of building llc_sibling mask remains unchanged.

Link: https://lore.kernel.org/r/20220704101605.1318280-10-sudeep.holla@arm.com


Tested-by: default avatarIonela Voinescu <ionela.voinescu@arm.com>
Tested-by: default avatarConor Dooley <conor.dooley@microchip.com>
Reviewed-by: default avatarGavin Shan <gshan@redhat.com>
Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent 52110313

drivers/base/arch_topology.c

+21 −7
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
 */



#include <linux/acpi.h>

#include <linux/cacheinfo.h>

#include <linux/cpu.h>

#include <linux/cpufreq.h>

#include <linux/device.h>
@@ -780,15 +781,28 @@ __weak int __init parse_acpi_topology(void) 
#if defined(CONFIG_ARM64) || defined(CONFIG_RISCV)

void __init init_cpu_topology(void)

{

	int ret, cpu;



	reset_cpu_topology();

	ret = parse_acpi_topology();

	if (!ret)

		ret = of_have_populated_dt() && parse_dt_topology();



	if (ret) {

		/*

		 * Discard anything that was parsed if we hit an error so we

		 * don't use partial information.

		 */

	if (parse_acpi_topology())

		reset_cpu_topology();

	else if (of_have_populated_dt() && parse_dt_topology())

		reset_cpu_topology();

		return;

	}



	for_each_possible_cpu(cpu) {

		ret = detect_cache_attributes(cpu);

		if (ret) {

			pr_info("Early cacheinfo failed, ret = %d\n", ret);

			break;

		}

	}

}

#endif