diff options
Diffstat (limited to 'arch/x86/kernel/apic/x2apic_cluster.c')
| -rw-r--r-- | arch/x86/kernel/apic/x2apic_cluster.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c new file mode 100644 index 000000000..e696e22d0 --- /dev/null +++ b/arch/x86/kernel/apic/x2apic_cluster.c @@ -0,0 +1,241 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/cpuhotplug.h> +#include <linux/cpumask.h> +#include <linux/slab.h> +#include <linux/mm.h> + +#include <asm/apic.h> + +#include "local.h" + +struct cluster_mask { + unsigned int clusterid; + int node; + struct cpumask mask; +}; + +/* + * __x2apic_send_IPI_mask() possibly needs to read + * x86_cpu_to_logical_apicid for all online cpus in a sequential way. + * Using per cpu variable would cost one cache line per cpu. + */ +static u32 *x86_cpu_to_logical_apicid __read_mostly; + +static DEFINE_PER_CPU(cpumask_var_t, ipi_mask); +static DEFINE_PER_CPU_READ_MOSTLY(struct cluster_mask *, cluster_masks); +static struct cluster_mask *cluster_hotplug_mask; + +static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id) +{ + return x2apic_enabled(); +} + +static void x2apic_send_IPI(int cpu, int vector) +{ + u32 dest = x86_cpu_to_logical_apicid[cpu]; + + /* x2apic MSRs are special and need a special fence: */ + weak_wrmsr_fence(); + __x2apic_send_IPI_dest(dest, vector, APIC_DEST_LOGICAL); +} + +static void +__x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest) +{ + unsigned int cpu, clustercpu; + struct cpumask *tmpmsk; + unsigned long flags; + u32 dest; + + /* x2apic MSRs are special and need a special fence: */ + weak_wrmsr_fence(); + local_irq_save(flags); + + tmpmsk = this_cpu_cpumask_var_ptr(ipi_mask); + cpumask_copy(tmpmsk, mask); + /* If IPI should not be sent to self, clear current CPU */ + if (apic_dest != APIC_DEST_ALLINC) + __cpumask_clear_cpu(smp_processor_id(), tmpmsk); + + /* Collapse cpus in a cluster so a single IPI per cluster is sent */ + for_each_cpu(cpu, tmpmsk) { + struct cluster_mask *cmsk = per_cpu(cluster_masks, cpu); + + dest = 0; + for_each_cpu_and(clustercpu, tmpmsk, &cmsk->mask) + dest |= x86_cpu_to_logical_apicid[clustercpu]; + + if (!dest) + continue; + + __x2apic_send_IPI_dest(dest, vector, APIC_DEST_LOGICAL); + /* Remove cluster CPUs from tmpmask */ + cpumask_andnot(tmpmsk, tmpmsk, &cmsk->mask); + } + + local_irq_restore(flags); +} + +static void x2apic_send_IPI_mask(const struct cpumask *mask, int vector) +{ + __x2apic_send_IPI_mask(mask, vector, APIC_DEST_ALLINC); +} + +static void +x2apic_send_IPI_mask_allbutself(const struct cpumask *mask, int vector) +{ + __x2apic_send_IPI_mask(mask, vector, APIC_DEST_ALLBUT); +} + +static void x2apic_send_IPI_allbutself(int vector) +{ + __x2apic_send_IPI_shorthand(vector, APIC_DEST_ALLBUT); +} + +static void x2apic_send_IPI_all(int vector) +{ + __x2apic_send_IPI_shorthand(vector, APIC_DEST_ALLINC); +} + +static u32 x2apic_calc_apicid(unsigned int cpu) +{ + return x86_cpu_to_logical_apicid[cpu]; +} + +static void init_x2apic_ldr(void) +{ + struct cluster_mask *cmsk = this_cpu_read(cluster_masks); + u32 cluster, apicid = apic_read(APIC_LDR); + unsigned int cpu; + + x86_cpu_to_logical_apicid[smp_processor_id()] = apicid; + + if (cmsk) + goto update; + + cluster = apicid >> 16; + for_each_online_cpu(cpu) { + cmsk = per_cpu(cluster_masks, cpu); + /* Matching cluster found. Link and update it. */ + if (cmsk && cmsk->clusterid == cluster) + goto update; + } + cmsk = cluster_hotplug_mask; + cmsk->clusterid = cluster; + cluster_hotplug_mask = NULL; +update: + this_cpu_write(cluster_masks, cmsk); + cpumask_set_cpu(smp_processor_id(), &cmsk->mask); +} + +static int alloc_clustermask(unsigned int cpu, int node) +{ + if (per_cpu(cluster_masks, cpu)) + return 0; + /* + * If a hotplug spare mask exists, check whether it's on the right + * node. If not, free it and allocate a new one. + */ + if (cluster_hotplug_mask) { + if (cluster_hotplug_mask->node == node) + return 0; + kfree(cluster_hotplug_mask); + } + + cluster_hotplug_mask = kzalloc_node(sizeof(*cluster_hotplug_mask), + GFP_KERNEL, node); + if (!cluster_hotplug_mask) + return -ENOMEM; + cluster_hotplug_mask->node = node; + return 0; +} + +static int x2apic_prepare_cpu(unsigned int cpu) +{ + if (alloc_clustermask(cpu, cpu_to_node(cpu)) < 0) + return -ENOMEM; + if (!zalloc_cpumask_var(&per_cpu(ipi_mask, cpu), GFP_KERNEL)) + return -ENOMEM; + return 0; +} + +static int x2apic_dead_cpu(unsigned int dead_cpu) +{ + struct cluster_mask *cmsk = per_cpu(cluster_masks, dead_cpu); + + if (cmsk) + cpumask_clear_cpu(dead_cpu, &cmsk->mask); + free_cpumask_var(per_cpu(ipi_mask, dead_cpu)); + return 0; +} + +static int x2apic_cluster_probe(void) +{ + u32 slots; + + if (!x2apic_mode) + return 0; + + slots = max_t(u32, L1_CACHE_BYTES/sizeof(u32), nr_cpu_ids); + x86_cpu_to_logical_apicid = kcalloc(slots, sizeof(u32), GFP_KERNEL); + if (!x86_cpu_to_logical_apicid) + return 0; + + if (cpuhp_setup_state(CPUHP_X2APIC_PREPARE, "x86/x2apic:prepare", + x2apic_prepare_cpu, x2apic_dead_cpu) < 0) { + pr_err("Failed to register X2APIC_PREPARE\n"); + kfree(x86_cpu_to_logical_apicid); + x86_cpu_to_logical_apicid = NULL; + return 0; + } + init_x2apic_ldr(); + return 1; +} + +static struct apic apic_x2apic_cluster __ro_after_init = { + + .name = "cluster x2apic", + .probe = x2apic_cluster_probe, + .acpi_madt_oem_check = x2apic_acpi_madt_oem_check, + .apic_id_valid = x2apic_apic_id_valid, + .apic_id_registered = x2apic_apic_id_registered, + + .delivery_mode = APIC_DELIVERY_MODE_FIXED, + .dest_mode_logical = true, + + .disable_esr = 0, + + .check_apicid_used = NULL, + .init_apic_ldr = init_x2apic_ldr, + .ioapic_phys_id_map = NULL, + .setup_apic_routing = NULL, + .cpu_present_to_apicid = default_cpu_present_to_apicid, + .apicid_to_cpu_present = NULL, + .check_phys_apicid_present = default_check_phys_apicid_present, + .phys_pkg_id = x2apic_phys_pkg_id, + + .get_apic_id = x2apic_get_apic_id, + .set_apic_id = x2apic_set_apic_id, + + .calc_dest_apicid = x2apic_calc_apicid, + + .send_IPI = x2apic_send_IPI, + .send_IPI_mask = x2apic_send_IPI_mask, + .send_IPI_mask_allbutself = x2apic_send_IPI_mask_allbutself, + .send_IPI_allbutself = x2apic_send_IPI_allbutself, + .send_IPI_all = x2apic_send_IPI_all, + .send_IPI_self = x2apic_send_IPI_self, + + .inquire_remote_apic = NULL, + + .read = native_apic_msr_read, + .write = native_apic_msr_write, + .eoi_write = native_apic_msr_eoi_write, + .icr_read = native_x2apic_icr_read, + .icr_write = native_x2apic_icr_write, + .wait_icr_idle = native_x2apic_wait_icr_idle, + .safe_wait_icr_idle = native_safe_x2apic_wait_icr_idle, +}; + +apic_driver(apic_x2apic_cluster); |