From: Dietmar Eggemann dietmar.eggemann@arm.com
[ Upstream commit ff98a5f624d2910de050f1fc7f2a32769da86b51 ]
Commit ca74b316df96 ("arm: Use common cpu_topology structure and functions.") changed cpu_coregroup_mask() from the ARM32 specific implementation in arch/arm/include/asm/topology.h to the one shared with ARM64 and RISCV in drivers/base/arch_topology.c.
Currently on ARM32 (TC2 w/ CONFIG_SCHED_MC) the task scheduler setup code (w/ CONFIG_SCHED_DEBUG) shows this during CPU hotplug:
ERROR: groups don't span domain->span
It happens to CPUs of the cluster of the CPU which gets hot-plugged out on scheduler domain MC.
Turns out that the shared cpu_coregroup_mask() requires that the hot-plugged CPU is removed from the core_sibling mask via remove_cpu_topology(). Otherwise the 'is core_sibling subset of cpumask_of_node()' doesn't work. In this case the task scheduler has to deal with cpumask_of_node instead of core_sibling which is wrong on scheduler domain MC.
e.g. CPU3 hot-plugged out on TC2 [cluster0: 0,3-4 cluster1: 1-2]:
cpu_coregroup_mask(): CPU3 cpumask_of_node=0-2,4 core_sibling=0,3-4 ^ should be:
cpu_coregroup_mask(): CPU3 cpumask_of_node=0-2,4 core_sibling=0,4
Add remove_cpu_topology() to __cpu_disable() to remove the CPU from the topology masks in case of a CPU hotplug out operation.
At the same time tweak store_cpu_topology() slightly so it will call update_siblings_masks() in case of CPU hotplug in operation via secondary_start_kernel()->smp_store_cpu_info().
This aligns the ARM32 implementation with the ARM64 one.
Guarding remove_cpu_topology() with CONFIG_GENERIC_ARCH_TOPOLOGY is necessary since some Arm32 defconfigs (aspeed_g5_defconfig, milbeaut_m10v_defconfig, spear13xx_defconfig) specify an explicit
# CONFIG_ARM_CPU_TOPOLOGY is not set
w/ ./arch/arm/Kconfig: select GENERIC_ARCH_TOPOLOGY if ARM_CPU_TOPOLOGY
Fixes: ca74b316df96 ("arm: Use common cpu_topology structure and functions") Reviewed-by: Sudeep Holla sudeep.holla@arm.com Reviewed-by: Lukasz Luba lukasz.luba@arm.com Tested-by: Lukasz Luba lukasz.luba@arm.com Tested-by: Ondrej Jirman megous@megous.com Signed-off-by: Dietmar Eggemann dietmar.eggemann@arm.com Signed-off-by: Russell King rmk+kernel@armlinux.org.uk Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm/kernel/smp.c | 4 ++++ arch/arm/kernel/topology.c | 10 +++++----- 2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 4b0bab2607e4..46e1be9e57a8 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -240,6 +240,10 @@ int __cpu_disable(void) if (ret) return ret;
+#ifdef CONFIG_GENERIC_ARCH_TOPOLOGY + remove_cpu_topology(cpu); +#endif + /* * Take this CPU offline. Once we clear this, we can't return, * and we must not schedule until we're ready to give up the cpu. diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index 5b9faba03afb..8d2e61d9e7a6 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -196,9 +196,8 @@ void store_cpu_topology(unsigned int cpuid) struct cpu_topology *cpuid_topo = &cpu_topology[cpuid]; unsigned int mpidr;
- /* If the cpu topology has been already set, just return */ - if (cpuid_topo->core_id != -1) - return; + if (cpuid_topo->package_id != -1) + goto topology_populated;
mpidr = read_cpuid_mpidr();
@@ -231,14 +230,15 @@ void store_cpu_topology(unsigned int cpuid) cpuid_topo->package_id = -1; }
- update_siblings_masks(cpuid); - update_cpu_capacity(cpuid);
pr_info("CPU%u: thread %d, cpu %d, socket %d, mpidr %x\n", cpuid, cpu_topology[cpuid].thread_id, cpu_topology[cpuid].core_id, cpu_topology[cpuid].package_id, mpidr); + +topology_populated: + update_siblings_masks(cpuid); }
static inline int cpu_corepower_flags(void)