diff options
Diffstat (limited to 'arch/powerpc/kernel/smp.c')
| -rw-r--r-- | arch/powerpc/kernel/smp.c | 245 |
1 files changed, 244 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 61c1fadbc644..3f15edf25a0d 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -34,6 +34,8 @@ #include <linux/topology.h> #include <linux/profile.h> #include <linux/processor.h> +#include <linux/random.h> +#include <linux/stackprotector.h> #include <asm/ptrace.h> #include <linux/atomic.h> @@ -74,14 +76,32 @@ static DEFINE_PER_CPU(int, cpu_state) = { 0 }; #endif struct thread_info *secondary_ti; +bool has_big_cores; DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map); +DEFINE_PER_CPU(cpumask_var_t, cpu_smallcore_map); DEFINE_PER_CPU(cpumask_var_t, cpu_l2_cache_map); DEFINE_PER_CPU(cpumask_var_t, cpu_core_map); EXPORT_PER_CPU_SYMBOL(cpu_sibling_map); EXPORT_PER_CPU_SYMBOL(cpu_l2_cache_map); EXPORT_PER_CPU_SYMBOL(cpu_core_map); +EXPORT_SYMBOL_GPL(has_big_cores); + +#define MAX_THREAD_LIST_SIZE 8 +#define THREAD_GROUP_SHARE_L1 1 +struct thread_groups { + unsigned int property; + unsigned int nr_groups; + unsigned int threads_per_group; + unsigned int thread_list[MAX_THREAD_LIST_SIZE]; +}; + +/* + * On big-cores system, cpu_l1_cache_map for each CPU corresponds to + * the set its siblings that share the L1-cache. + */ +DEFINE_PER_CPU(cpumask_var_t, cpu_l1_cache_map); /* SMP operations for this machine */ struct smp_ops_t *smp_ops; @@ -674,6 +694,185 @@ static void set_cpus_unrelated(int i, int j, } #endif +/* + * parse_thread_groups: Parses the "ibm,thread-groups" device tree + * property for the CPU device node @dn and stores + * the parsed output in the thread_groups + * structure @tg if the ibm,thread-groups[0] + * matches @property. + * + * @dn: The device node of the CPU device. + * @tg: Pointer to a thread group structure into which the parsed + * output of "ibm,thread-groups" is stored. + * @property: The property of the thread-group that the caller is + * interested in. + * + * ibm,thread-groups[0..N-1] array defines which group of threads in + * the CPU-device node can be grouped together based on the property. + * + * ibm,thread-groups[0] tells us the property based on which the + * threads are being grouped together. If this value is 1, it implies + * that the threads in the same group share L1, translation cache. + * + * ibm,thread-groups[1] tells us how many such thread groups exist. + * + * ibm,thread-groups[2] tells us the number of threads in each such + * group. + * + * ibm,thread-groups[3..N-1] is the list of threads identified by + * "ibm,ppc-interrupt-server#s" arranged as per their membership in + * the grouping. + * + * Example: If ibm,thread-groups = [1,2,4,5,6,7,8,9,10,11,12] it + * implies that there are 2 groups of 4 threads each, where each group + * of threads share L1, translation cache. + * + * The "ibm,ppc-interrupt-server#s" of the first group is {5,6,7,8} + * and the "ibm,ppc-interrupt-server#s" of the second group is {9, 10, + * 11, 12} structure + * + * Returns 0 on success, -EINVAL if the property does not exist, + * -ENODATA if property does not have a value, and -EOVERFLOW if the + * property data isn't large enough. + */ +static int parse_thread_groups(struct device_node *dn, + struct thread_groups *tg, + unsigned int property) +{ + int i; + u32 thread_group_array[3 + MAX_THREAD_LIST_SIZE]; + u32 *thread_list; + size_t total_threads; + int ret; + + ret = of_property_read_u32_array(dn, "ibm,thread-groups", + thread_group_array, 3); + if (ret) + return ret; + + tg->property = thread_group_array[0]; + tg->nr_groups = thread_group_array[1]; + tg->threads_per_group = thread_group_array[2]; + if (tg->property != property || + tg->nr_groups < 1 || + tg->threads_per_group < 1) + return -ENODATA; + + total_threads = tg->nr_groups * tg->threads_per_group; + + ret = of_property_read_u32_array(dn, "ibm,thread-groups", + thread_group_array, + 3 + total_threads); + if (ret) + return ret; + + thread_list = &thread_group_array[3]; + + for (i = 0 ; i < total_threads; i++) + tg->thread_list[i] = thread_list[i]; + + return 0; +} + +/* + * get_cpu_thread_group_start : Searches the thread group in tg->thread_list + * that @cpu belongs to. + * + * @cpu : The logical CPU whose thread group is being searched. + * @tg : The thread-group structure of the CPU node which @cpu belongs + * to. + * + * Returns the index to tg->thread_list that points to the the start + * of the thread_group that @cpu belongs to. + * + * Returns -1 if cpu doesn't belong to any of the groups pointed to by + * tg->thread_list. + */ +static int get_cpu_thread_group_start(int cpu, struct thread_groups *tg) +{ + int hw_cpu_id = get_hard_smp_processor_id(cpu); + int i, j; + + for (i = 0; i < tg->nr_groups; i++) { + int group_start = i * tg->threads_per_group; + + for (j = 0; j < tg->threads_per_group; j++) { + int idx = group_start + j; + + if (tg->thread_list[idx] == hw_cpu_id) + return group_start; + } + } + + return -1; +} + +static int init_cpu_l1_cache_map(int cpu) + +{ + struct device_node *dn = of_get_cpu_node(cpu, NULL); + struct thread_groups tg = {.property = 0, + .nr_groups = 0, + .threads_per_group = 0}; + int first_thread = cpu_first_thread_sibling(cpu); + int i, cpu_group_start = -1, err = 0; + + if (!dn) + return -ENODATA; + + err = parse_thread_groups(dn, &tg, THREAD_GROUP_SHARE_L1); + if (err) + goto out; + + zalloc_cpumask_var_node(&per_cpu(cpu_l1_cache_map, cpu), + GFP_KERNEL, + cpu_to_node(cpu)); + + cpu_group_start = get_cpu_thread_group_start(cpu, &tg); + + if (unlikely(cpu_group_start == -1)) { + WARN_ON_ONCE(1); + err = -ENODATA; + goto out; + } + + for (i = first_thread; i < first_thread + threads_per_core; i++) { + int i_group_start = get_cpu_thread_group_start(i, &tg); + + if (unlikely(i_group_start == -1)) { + WARN_ON_ONCE(1); + err = -ENODATA; + goto out; + } + + if (i_group_start == cpu_group_start) + cpumask_set_cpu(i, per_cpu(cpu_l1_cache_map, cpu)); + } + +out: + of_node_put(dn); + return err; +} + +static int init_big_cores(void) +{ + int cpu; + + for_each_possible_cpu(cpu) { + int err = init_cpu_l1_cache_map(cpu); + + if (err) + return err; + + zalloc_cpumask_var_node(&per_cpu(cpu_smallcore_map, cpu), + GFP_KERNEL, + cpu_to_node(cpu)); + } + + has_big_cores = true; + return 0; +} + void __init smp_prepare_cpus(unsigned int max_cpus) { unsigned int cpu; @@ -712,6 +911,12 @@ void __init smp_prepare_cpus(unsigned int max_cpus) cpumask_set_cpu(boot_cpuid, cpu_l2_cache_mask(boot_cpuid)); cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid)); + init_big_cores(); + if (has_big_cores) { + cpumask_set_cpu(boot_cpuid, + cpu_smallcore_mask(boot_cpuid)); + } + if (smp_ops && smp_ops->probe) smp_ops->probe(); } @@ -995,10 +1200,28 @@ static void remove_cpu_from_masks(int cpu) set_cpus_unrelated(cpu, i, cpu_core_mask); set_cpus_unrelated(cpu, i, cpu_l2_cache_mask); set_cpus_unrelated(cpu, i, cpu_sibling_mask); + if (has_big_cores) + set_cpus_unrelated(cpu, i, cpu_smallcore_mask); } } #endif +static inline void add_cpu_to_smallcore_masks(int cpu) +{ + struct cpumask *this_l1_cache_map = per_cpu(cpu_l1_cache_map, cpu); + int i, first_thread = cpu_first_thread_sibling(cpu); + + if (!has_big_cores) + return; + + cpumask_set_cpu(cpu, cpu_smallcore_mask(cpu)); + + for (i = first_thread; i < first_thread + threads_per_core; i++) { + if (cpu_online(i) && cpumask_test_cpu(i, this_l1_cache_map)) + set_cpus_related(i, cpu, cpu_smallcore_mask); + } +} + static void add_cpu_to_masks(int cpu) { int first_thread = cpu_first_thread_sibling(cpu); @@ -1015,6 +1238,7 @@ static void add_cpu_to_masks(int cpu) if (cpu_online(i)) set_cpus_related(i, cpu, cpu_sibling_mask); + add_cpu_to_smallcore_masks(cpu); /* * Copy the thread sibling mask into the cache sibling mask * and mark any CPUs that share an L2 with this CPU. @@ -1044,6 +1268,7 @@ static bool shared_caches; void start_secondary(void *unused) { unsigned int cpu = smp_processor_id(); + struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask; mmgrab(&init_mm); current->active_mm = &init_mm; @@ -1069,11 +1294,13 @@ void start_secondary(void *unused) /* Update topology CPU masks */ add_cpu_to_masks(cpu); + if (has_big_cores) + sibling_mask = cpu_smallcore_mask; /* * Check for any shared caches. Note that this must be done on a * per-core basis because one core in the pair might be disabled. */ - if (!cpumask_equal(cpu_l2_cache_mask(cpu), cpu_sibling_mask(cpu))) + if (!cpumask_equal(cpu_l2_cache_mask(cpu), sibling_mask(cpu))) shared_caches = true; set_numa_node(numa_cpu_lookup_table[cpu]); @@ -1083,6 +1310,8 @@ void start_secondary(void *unused) notify_cpu_starting(cpu); set_cpu_online(cpu, true); + boot_init_stack_canary(); + local_irq_enable(); /* We can enable ftrace for secondary cpus now */ @@ -1140,6 +1369,13 @@ static const struct cpumask *shared_cache_mask(int cpu) return cpu_l2_cache_mask(cpu); } +#ifdef CONFIG_SCHED_SMT +static const struct cpumask *smallcore_smt_mask(int cpu) +{ + return cpu_smallcore_mask(cpu); +} +#endif + static struct sched_domain_topology_level power9_topology[] = { #ifdef CONFIG_SCHED_SMT { cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) }, @@ -1167,6 +1403,13 @@ void __init smp_cpus_done(unsigned int max_cpus) shared_proc_topology_init(); dump_numa_cpu_topology(); +#ifdef CONFIG_SCHED_SMT + if (has_big_cores) { + pr_info("Using small cores at SMT level\n"); + power9_topology[0].mask = smallcore_smt_mask; + powerpc_topology[0].mask = smallcore_smt_mask; + } +#endif /* * If any CPU detects that it's sharing a cache with another CPU then * use the deeper topology that is aware of this sharing. |