Commit e129309b authored by Yicong Yang's avatar Yicong Yang Committed by caodongxia
Browse files

arm64: topology: Support SMT control on ACPI based system 

kunpeng inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8TAPW
CVE: NA

Reference: https://lore.kernel.org/all/20231121092602.47792-1-yangyicong@huawei.com/



----------------------------------------------------------------------

For ACPI we'll build the topology from PPTT and we cannot directly
get the SMT number of each core. Instead using a temporary xarray
to record the SMT number of each core when building the topology
and we can know the largest SMT number in the system. Then we can
notify the arch_topology for supporting SMT control.

Signed-off-by: default avatarYicong Yang <yangyicong@hisilicon.com>
Signed-off-by: default avatarJie Liu <liujie375@h-partners.com>
Signed-off-by: default avatarcaodongxia <caodongxia1@h-partners.com>
parent 1e4cc203

arch/arm64/kernel/topology.c

+23 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/cpufreq.h>

#include <linux/init.h>

#include <linux/percpu.h>

#include <linux/xarray.h>



#include <asm/cpu.h>

#include <asm/cputype.h>
@@ -90,11 +91,16 @@ static bool __init acpi_cpu_is_threaded(int cpu) 
 */

int __init parse_acpi_topology(void)

{

	int thread_num, max_smt_thread_num = 1;

	struct xarray core_threads;

	int cpu, topology_id, ret;

	void *entry;



	if (acpi_disabled)

		return 0;



	xa_init(&core_threads);



	ret = acpi_pptt_init();

	if (ret)

		return ret;
@@ -110,6 +116,20 @@ int __init parse_acpi_topology(void) 
			cpu_topology[cpu].thread_id = topology_id;

			topology_id = find_acpi_cpu_topology(cpu, 1);

			cpu_topology[cpu].core_id   = topology_id;



			entry = xa_load(&core_threads, topology_id);

			if (!entry) {

				xa_store(&core_threads, topology_id,

					 xa_mk_value(1), GFP_KERNEL);

			} else {

				thread_num = xa_to_value(entry);

				thread_num++;

				xa_store(&core_threads, topology_id,

					 xa_mk_value(thread_num), GFP_KERNEL);



				if (thread_num > max_smt_thread_num)

					max_smt_thread_num = thread_num;

			}

		} else {

			cpu_topology[cpu].thread_id  = -1;

			cpu_topology[cpu].core_id    = topology_id;
@@ -132,6 +152,9 @@ int __init parse_acpi_topology(void) 
		}

	}



	topology_smt_set_num_threads(max_smt_thread_num);



	xa_destroy(&core_threads);

	return 0;

}

#endif