| Message ID | 20190808204007.30110-3-jeremy.linton@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64/PPTT ACPI 6.3 thread flag support | expand |
On 08.08.19 15:40:07, Jeremy Linton wrote: > 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> > --- > arch/arm64/kernel/topology.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c > index 0825c4a856e3..bad9c42ea825 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 int __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; Since this is no longer bool now, better have a !!(...) or (...) != 0 here. > + > + 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; Looks otherwise ok. Reviewed-by: Robert Richter <rrichter@marvell.com>
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 0825c4a856e3..bad9c42ea825 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 int __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;