From 440a0857e32a05979fb01fc59ea454a723e80e4b Mon Sep 17 00:00:00 2001 From: Nathan Lynch Date: Sun, 27 Jul 2008 15:24:53 +1000 Subject: [PATCH] powerpc: Make core sibling information available to userspace Implement the notion of "core siblings" for powerpc. This makes /sys/devices/system/cpu/cpu*/topology/core_siblings present sensible values, indicating online CPUs which share an L2 cache. BenH: Made cpu_to_l2cache() use of_find_node_by_phandle() instead of IBM-specific open coded search Signed-off-by: Nathan Lynch Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/smp.c | 64 ++++++++++++++++++++++++++++++++++ include/asm-powerpc/smp.h | 1 + include/asm-powerpc/topology.h | 1 + 3 files changed, 66 insertions(+) diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 3c4d07e5e06..f7a2f81b5b7 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -63,10 +63,12 @@ struct thread_info *secondary_ti; cpumask_t cpu_possible_map = CPU_MASK_NONE; cpumask_t cpu_online_map = CPU_MASK_NONE; DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE; +DEFINE_PER_CPU(cpumask_t, cpu_core_map) = CPU_MASK_NONE; EXPORT_SYMBOL(cpu_online_map); EXPORT_SYMBOL(cpu_possible_map); EXPORT_PER_CPU_SYMBOL(cpu_sibling_map); +EXPORT_PER_CPU_SYMBOL(cpu_core_map); /* SMP operations for this machine */ struct smp_ops_t *smp_ops; @@ -230,6 +232,7 @@ void __devinit smp_prepare_boot_cpu(void) cpu_set(boot_cpuid, cpu_online_map); cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid)); + cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid)); #ifdef CONFIG_PPC64 paca[boot_cpuid].__current = current; #endif @@ -377,11 +380,36 @@ int __cpuinit __cpu_up(unsigned int cpu) return 0; } +/* Must be called when no change can occur to cpu_present_map, + * i.e. during cpu online or offline. + */ +static struct device_node *cpu_to_l2cache(int cpu) +{ + struct device_node *np; + const phandle *php; + phandle ph; + + if (!cpu_present(cpu)) + return NULL; + + np = of_get_cpu_node(cpu, NULL); + if (np == NULL) + return NULL; + + php = of_get_property(np, "l2-cache", NULL); + if (php == NULL) + return NULL; + ph = *php; + of_node_put(np); + + return of_find_node_by_phandle(ph); +} /* Activate a secondary processor. */ int __devinit start_secondary(void *unused) { unsigned int cpu = smp_processor_id(); + struct device_node *l2_cache; int i, base; atomic_inc(&init_mm.mm_count); @@ -410,7 +438,26 @@ int __devinit start_secondary(void *unused) continue; cpu_set(cpu, per_cpu(cpu_sibling_map, base + i)); cpu_set(base + i, per_cpu(cpu_sibling_map, cpu)); + + /* cpu_core_map should be a superset of + * cpu_sibling_map even if we don't have cache + * information, so update the former here, too. + */ + cpu_set(cpu, per_cpu(cpu_core_map, base +i)); + cpu_set(base + i, per_cpu(cpu_core_map, cpu)); } + l2_cache = cpu_to_l2cache(cpu); + for_each_online_cpu(i) { + struct device_node *np = cpu_to_l2cache(i); + if (!np) + continue; + if (np == l2_cache) { + cpu_set(cpu, per_cpu(cpu_core_map, i)); + cpu_set(i, per_cpu(cpu_core_map, cpu)); + } + of_node_put(np); + } + of_node_put(l2_cache); ipi_call_unlock(); local_irq_enable(); @@ -448,6 +495,7 @@ void __init smp_cpus_done(unsigned int max_cpus) #ifdef CONFIG_HOTPLUG_CPU int __cpu_disable(void) { + struct device_node *l2_cache; int cpu = smp_processor_id(); int base, i; int err; @@ -464,7 +512,23 @@ int __cpu_disable(void) for (i = 0; i < threads_per_core; i++) { cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i)); cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu)); + cpu_clear(cpu, per_cpu(cpu_core_map, base +i)); + cpu_clear(base + i, per_cpu(cpu_core_map, cpu)); + } + + l2_cache = cpu_to_l2cache(cpu); + for_each_present_cpu(i) { + struct device_node *np = cpu_to_l2cache(i); + if (!np) + continue; + if (np == l2_cache) { + cpu_clear(cpu, per_cpu(cpu_core_map, i)); + cpu_clear(i, per_cpu(cpu_core_map, cpu)); + } + of_node_put(np); } + of_node_put(l2_cache); + return 0; } diff --git a/include/asm-powerpc/smp.h b/include/asm-powerpc/smp.h index 416d4c288ce..32e91000625 100644 --- a/include/asm-powerpc/smp.h +++ b/include/asm-powerpc/smp.h @@ -62,6 +62,7 @@ extern int smp_hw_index[]; #endif DECLARE_PER_CPU(cpumask_t, cpu_sibling_map); +DECLARE_PER_CPU(cpumask_t, cpu_core_map); /* Since OpenPIC has only 4 IPIs, we use slightly different message numbers. * diff --git a/include/asm-powerpc/topology.h b/include/asm-powerpc/topology.h index 100c6fbfc58..f00e8e55173 100644 --- a/include/asm-powerpc/topology.h +++ b/include/asm-powerpc/topology.h @@ -108,6 +108,7 @@ static inline void sysfs_remove_device_from_node(struct sys_device *dev, #include #define topology_thread_siblings(cpu) (per_cpu(cpu_sibling_map, cpu)) +#define topology_core_siblings(cpu) (per_cpu(cpu_core_map, cpu)) #endif #endif -- 2.41.1