arch/x86/kernel/apic/x2apic_cluster.c

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