diff options
author | Jeremy Linton <jeremy.linton@arm.com> | 2019-08-08 15:40:07 -0500 |
---|---|---|
committer | Will Deacon <will@kernel.org> | 2019-08-12 18:00:08 +0100 |
commit | 98dc19902a0b2e5348e43d6a2c39a0a7d0fc639e (patch) | |
tree | 257183e6410787e0e9321c5de9d80be76810d6ab /arch/arm64/kernel/topology.c | |
parent | bbd1b70639f785a970d998f35155c713f975e3ac (diff) |
arm64: topology: Use PPTT to determine if PE is a thread
ACPI 6.3 adds a thread flag to represent if a CPU/PE is
actually a thread. Given that the MPIDR_MT bit may not
represent this information consistently on homogeneous machines
we should prefer the PPTT flag if its available.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Robert Richter <rrichter@marvell.com>
[will: made acpi_cpu_is_threaded() return 'bool']
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel/topology.c')
-rw-r--r-- | arch/arm64/kernel/topology.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 0825c4a856e3..6106c49f84bc 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -340,17 +340,28 @@ void remove_cpu_topology(unsigned int cpu) } #ifdef CONFIG_ACPI +static bool __init acpi_cpu_is_threaded(int cpu) +{ + int is_threaded = acpi_pptt_cpu_is_thread(cpu); + + /* + * if the PPTT doesn't have thread information, assume a homogeneous + * machine and return the current CPU's thread state. + */ + if (is_threaded < 0) + is_threaded = read_cpuid_mpidr() & MPIDR_MT_BITMASK; + + return !!is_threaded; +} + /* * Propagate the topology information of the processor_topology_node tree to the * cpu_topology array. */ static int __init parse_acpi_topology(void) { - bool is_threaded; int cpu, topology_id; - is_threaded = read_cpuid_mpidr() & MPIDR_MT_BITMASK; - for_each_possible_cpu(cpu) { int i, cache_id; @@ -358,7 +369,7 @@ static int __init parse_acpi_topology(void) if (topology_id < 0) return topology_id; - if (is_threaded) { + if (acpi_cpu_is_threaded(cpu)) { cpu_topology[cpu].thread_id = topology_id; topology_id = find_acpi_cpu_topology(cpu, 1); cpu_topology[cpu].core_id = topology_id; |