Messages in this thread | | | From | Atish Patra <> | Date | Tue, 26 Jul 2022 01:10:10 -0700 | Subject | Re: [PATCH v4 1/2] arm64: topology: move store_cpu_topology() to shared code |
| |
On Fri, Jul 15, 2022 at 10:53 AM Conor Dooley <mail@conchuod.ie> wrote: > > From: Conor Dooley <conor.dooley@microchip.com> > > arm64's method of defining a default cpu topology requires only minimal > changes to apply to RISC-V also. The current arm64 implementation exits > early in a uniprocessor configuration by reading MPIDR & claiming that > uniprocessor can rely on the default values. > > This is appears to be a hangover from prior to '3102bc0e6ac7 ("arm64: > topology: Stop using MPIDR for topology information")', because the > current code just assigns default values for multiprocessor systems. > > With the MPIDR references removed, store_cpu_topolgy() can be moved to > the common arch_topology code. > > CC: stable@vger.kernel.org > Signed-off-by: Conor Dooley <conor.dooley@microchip.com> > Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> > --- > arch/arm64/kernel/topology.c | 40 ------------------------------------ > drivers/base/arch_topology.c | 19 +++++++++++++++++ > 2 files changed, 19 insertions(+), 40 deletions(-) > > diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c > index 869ffc4d4484..7889a00f5487 100644 > --- a/arch/arm64/kernel/topology.c > +++ b/arch/arm64/kernel/topology.c > @@ -22,46 +22,6 @@ > #include <asm/cputype.h> > #include <asm/topology.h> > > -void store_cpu_topology(unsigned int cpuid) > -{ > - struct cpu_topology *cpuid_topo = &cpu_topology[cpuid]; > - u64 mpidr; > - > - if (cpuid_topo->package_id != -1) > - goto topology_populated; > - > - mpidr = read_cpuid_mpidr(); > - > - /* Uniprocessor systems can rely on default topology values */ > - if (mpidr & MPIDR_UP_BITMASK) > - return; > - > - /* > - * This would be the place to create cpu topology based on MPIDR. > - * > - * However, it cannot be trusted to depict the actual topology; some > - * pieces of the architecture enforce an artificial cap on Aff0 values > - * (e.g. GICv3's ICC_SGI1R_EL1 limits it to 15), leading to an > - * artificial cycling of Aff1, Aff2 and Aff3 values. IOW, these end up > - * having absolutely no relationship to the actual underlying system > - * topology, and cannot be reasonably used as core / package ID. > - * > - * If the MT bit is set, Aff0 *could* be used to define a thread ID, but > - * we still wouldn't be able to obtain a sane core ID. This means we > - * need to entirely ignore MPIDR for any topology deduction. > - */ > - cpuid_topo->thread_id = -1; > - cpuid_topo->core_id = cpuid; > - cpuid_topo->package_id = cpu_to_node(cpuid); > - > - pr_debug("CPU%u: cluster %d core %d thread %d mpidr %#016llx\n", > - cpuid, cpuid_topo->package_id, cpuid_topo->core_id, > - cpuid_topo->thread_id, mpidr); > - > -topology_populated: > - update_siblings_masks(cpuid); > -} > - > #ifdef CONFIG_ACPI > static bool __init acpi_cpu_is_threaded(int cpu) > { > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > index 0424b59b695e..0e2c6b30dd69 100644 > --- a/drivers/base/arch_topology.c > +++ b/drivers/base/arch_topology.c > @@ -841,4 +841,23 @@ void __init init_cpu_topology(void) > return; > } > } > + > +void store_cpu_topology(unsigned int cpuid) > +{ > + struct cpu_topology *cpuid_topo = &cpu_topology[cpuid]; > + > + if (cpuid_topo->package_id != -1) > + goto topology_populated; > + > + cpuid_topo->thread_id = -1; > + cpuid_topo->core_id = cpuid; > + cpuid_topo->package_id = cpu_to_node(cpuid); > + > + pr_debug("CPU%u: package %d core %d thread %d\n", > + cpuid, cpuid_topo->package_id, cpuid_topo->core_id, > + cpuid_topo->thread_id); > + > +topology_populated: > + update_siblings_masks(cpuid); > +} > #endif > -- > 2.37.1 >
LGTM. Reviewed-by: Atish Patra <atishp@rivosinc.com>
-- Regards, Atish
| |