arch/x86/kernel/apic/x2apic_cluster.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/cpuhotplug.h>
   4 #include <linux/cpumask.h>
   5 #include <linux/slab.h>
   6 #include <linux/mm.h>
   7
   8 #include <asm/apic.h>
   9
  10 #include "local.h"
  11
  12 struct cluster_mask {
  13         unsigned int    clusterid;
  14         int             node;
  15         struct cpumask  mask;
  16 };
  17
  18 static DEFINE_PER_CPU(u32, x86_cpu_to_logical_apicid);
  19 static DEFINE_PER_CPU(cpumask_var_t, ipi_mask);
  20 static DEFINE_PER_CPU(struct cluster_mask *, cluster_masks);
  21 static struct cluster_mask *cluster_hotplug_mask;
  22
  23 static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
  24 {
  25         return x2apic_enabled();
  26 }
  27
  28 static void x2apic_send_IPI(int cpu, int vector)
  29 {
  30         u32 dest = per_cpu(x86_cpu_to_logical_apicid, cpu);
  31
  32         x2apic_wrmsr_fence();
  33         __x2apic_send_IPI_dest(dest, vector, APIC_DEST_LOGICAL);
  34 }
  35
  36 static void
  37 __x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest)
  38 {
  39         unsigned int cpu, clustercpu;
  40         struct cpumask *tmpmsk;
  41         unsigned long flags;
  42         u32 dest;
  43
  44         x2apic_wrmsr_fence();
  45         local_irq_save(flags);
  46
  47         tmpmsk = this_cpu_cpumask_var_ptr(ipi_mask);
  48         cpumask_copy(tmpmsk, mask);
  49         /* If IPI should not be sent to self, clear current CPU */
  50         if (apic_dest != APIC_DEST_ALLINC)
  51                 __cpumask_clear_cpu(smp_processor_id(), tmpmsk);
  52
  53         /* Collapse cpus in a cluster so a single IPI per cluster is sent */
  54         for_each_cpu(cpu, tmpmsk) {
  55                 struct cluster_mask *cmsk = per_cpu(cluster_masks, cpu);
  56
  57                 dest = 0;
  58                 for_each_cpu_and(clustercpu, tmpmsk, &cmsk->mask)
  59                         dest |= per_cpu(x86_cpu_to_logical_apicid, clustercpu);
  60
  61                 if (!dest)
  62                         continue;
  63
  64                 __x2apic_send_IPI_dest(dest, vector, apic->dest_logical);
  65                 /* Remove cluster CPUs from tmpmask */
  66                 cpumask_andnot(tmpmsk, tmpmsk, &cmsk->mask);
  67         }
  68
  69         local_irq_restore(flags);
  70 }
  71
  72 static void x2apic_send_IPI_mask(const struct cpumask *mask, int vector)
  73 {
  74         __x2apic_send_IPI_mask(mask, vector, APIC_DEST_ALLINC);
  75 }
  76
  77 static void
  78 x2apic_send_IPI_mask_allbutself(const struct cpumask *mask, int vector)
  79 {
  80         __x2apic_send_IPI_mask(mask, vector, APIC_DEST_ALLBUT);
  81 }
  82
  83 static void x2apic_send_IPI_allbutself(int vector)
  84 {
  85         __x2apic_send_IPI_shorthand(vector, APIC_DEST_ALLBUT);
  86 }
  87
  88 static void x2apic_send_IPI_all(int vector)
  89 {
  90         __x2apic_send_IPI_shorthand(vector, APIC_DEST_ALLINC);
  91 }
  92
  93 static u32 x2apic_calc_apicid(unsigned int cpu)
  94 {
  95         return per_cpu(x86_cpu_to_logical_apicid, cpu);
  96 }
  97
  98 static void init_x2apic_ldr(void)
  99 {
 100         struct cluster_mask *cmsk = this_cpu_read(cluster_masks);
 101         u32 cluster, apicid = apic_read(APIC_LDR);
 102         unsigned int cpu;
 103
 104         this_cpu_write(x86_cpu_to_logical_apicid, apicid);
 105
 106         if (cmsk)
 107                 goto update;
 108
 109         cluster = apicid >> 16;
 110         for_each_online_cpu(cpu) {
 111                 cmsk = per_cpu(cluster_masks, cpu);
 112                 /* Matching cluster found. Link and update it. */
 113                 if (cmsk && cmsk->clusterid == cluster)
 114                         goto update;
 115         }
 116         cmsk = cluster_hotplug_mask;
 117         cmsk->clusterid = cluster;
 118         cluster_hotplug_mask = NULL;
 119 update:
 120         this_cpu_write(cluster_masks, cmsk);
 121         cpumask_set_cpu(smp_processor_id(), &cmsk->mask);
 122 }
 123
 124 static int alloc_clustermask(unsigned int cpu, int node)
 125 {
 126         if (per_cpu(cluster_masks, cpu))
 127                 return 0;
 128         /*
 129          * If a hotplug spare mask exists, check whether it's on the right
 130          * node. If not, free it and allocate a new one.
 131          */
 132         if (cluster_hotplug_mask) {
 133                 if (cluster_hotplug_mask->node == node)
 134                         return 0;
 135                 kfree(cluster_hotplug_mask);
 136         }
 137
 138         cluster_hotplug_mask = kzalloc_node(sizeof(*cluster_hotplug_mask),
 139                                             GFP_KERNEL, node);
 140         if (!cluster_hotplug_mask)
 141                 return -ENOMEM;
 142         cluster_hotplug_mask->node = node;
 143         return 0;
 144 }
 145
 146 static int x2apic_prepare_cpu(unsigned int cpu)
 147 {
 148         if (alloc_clustermask(cpu, cpu_to_node(cpu)) < 0)
 149                 return -ENOMEM;
 150         if (!zalloc_cpumask_var(&per_cpu(ipi_mask, cpu), GFP_KERNEL))
 151                 return -ENOMEM;
 152         return 0;
 153 }
 154
 155 static int x2apic_dead_cpu(unsigned int dead_cpu)
 156 {
 157         struct cluster_mask *cmsk = per_cpu(cluster_masks, dead_cpu);
 158
 159         if (cmsk)
 160                 cpumask_clear_cpu(dead_cpu, &cmsk->mask);
 161         free_cpumask_var(per_cpu(ipi_mask, dead_cpu));
 162         return 0;
 163 }
 164
 165 static int x2apic_cluster_probe(void)
 166 {
 167         if (!x2apic_mode)
 168                 return 0;
 169
 170         if (cpuhp_setup_state(CPUHP_X2APIC_PREPARE, "x86/x2apic:prepare",
 171                               x2apic_prepare_cpu, x2apic_dead_cpu) < 0) {
 172                 pr_err("Failed to register X2APIC_PREPARE\n");
 173                 return 0;
 174         }
 175         init_x2apic_ldr();
 176         return 1;
 177 }
 178
 179 static struct apic apic_x2apic_cluster __ro_after_init = {
 180
 181         .name                           = "cluster x2apic",
 182         .probe                          = x2apic_cluster_probe,
 183         .acpi_madt_oem_check            = x2apic_acpi_madt_oem_check,
 184         .apic_id_valid                  = x2apic_apic_id_valid,
 185         .apic_id_registered             = x2apic_apic_id_registered,
 186
 187         .irq_delivery_mode              = dest_Fixed,
 188         .irq_dest_mode                  = 1, /* logical */
 189
 190         .disable_esr                    = 0,
 191         .dest_logical                   = APIC_DEST_LOGICAL,
 192         .check_apicid_used              = NULL,
 193
 194         .init_apic_ldr                  = init_x2apic_ldr,
 195
 196         .ioapic_phys_id_map             = NULL,
 197         .setup_apic_routing             = NULL,
 198         .cpu_present_to_apicid          = default_cpu_present_to_apicid,
 199         .apicid_to_cpu_present          = NULL,
 200         .check_phys_apicid_present      = default_check_phys_apicid_present,
 201         .phys_pkg_id                    = x2apic_phys_pkg_id,
 202
 203         .get_apic_id                    = x2apic_get_apic_id,
 204         .set_apic_id                    = x2apic_set_apic_id,
 205
 206         .calc_dest_apicid               = x2apic_calc_apicid,
 207
 208         .send_IPI                       = x2apic_send_IPI,
 209         .send_IPI_mask                  = x2apic_send_IPI_mask,
 210         .send_IPI_mask_allbutself       = x2apic_send_IPI_mask_allbutself,
 211         .send_IPI_allbutself            = x2apic_send_IPI_allbutself,
 212         .send_IPI_all                   = x2apic_send_IPI_all,
 213         .send_IPI_self                  = x2apic_send_IPI_self,
 214
 215         .inquire_remote_apic            = NULL,
 216
 217         .read                           = native_apic_msr_read,
 218         .write                          = native_apic_msr_write,
 219         .eoi_write                      = native_apic_msr_eoi_write,
 220         .icr_read                       = native_x2apic_icr_read,
 221         .icr_write                      = native_x2apic_icr_write,
 222         .wait_icr_idle                  = native_x2apic_wait_icr_idle,
 223         .safe_wait_icr_idle             = native_safe_x2apic_wait_icr_idle,
 224 };
 225
 226 apic_driver(apic_x2apic_cluster);