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 MSRs are special and need a special fence: */
  33         weak_wrmsr_fence();
  34         __x2apic_send_IPI_dest(dest, vector, APIC_DEST_LOGICAL);
  35 }
  36
  37 static void
  38 __x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest)
  39 {
  40         unsigned int cpu, clustercpu;
  41         struct cpumask *tmpmsk;
  42         unsigned long flags;
  43         u32 dest;
  44
  45         /* x2apic MSRs are special and need a special fence: */
  46         weak_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_shorthand(vector, APIC_DEST_ALLBUT);
  88 }
  89
  90 static void x2apic_send_IPI_all(int vector)
  91 {
  92         __x2apic_send_IPI_shorthand(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         if (cmsk)
 162                 cpumask_clear_cpu(dead_cpu, &cmsk->mask);
 163         free_cpumask_var(per_cpu(ipi_mask, dead_cpu));
 164         return 0;
 165 }
 166
 167 static int x2apic_cluster_probe(void)
 168 {
 169         if (!x2apic_mode)
 170                 return 0;
 171
 172         if (cpuhp_setup_state(CPUHP_X2APIC_PREPARE, "x86/x2apic:prepare",
 173                               x2apic_prepare_cpu, x2apic_dead_cpu) < 0) {
 174                 pr_err("Failed to register X2APIC_PREPARE\n");
 175                 return 0;
 176         }
 177         init_x2apic_ldr();
 178         return 1;
 179 }
 180
 181 static struct apic apic_x2apic_cluster __ro_after_init = {
 182
 183         .name                           = "cluster x2apic",
 184         .probe                          = x2apic_cluster_probe,
 185         .acpi_madt_oem_check            = x2apic_acpi_madt_oem_check,
 186         .apic_id_valid                  = x2apic_apic_id_valid,
 187         .apic_id_registered             = x2apic_apic_id_registered,
 188
 189         .irq_delivery_mode              = dest_Fixed,
 190         .irq_dest_mode                  = 1, /* logical */
 191
 192         .disable_esr                    = 0,
 193         .dest_logical                   = APIC_DEST_LOGICAL,
 194         .check_apicid_used              = NULL,
 195
 196         .init_apic_ldr                  = init_x2apic_ldr,
 197
 198         .ioapic_phys_id_map             = NULL,
 199         .setup_apic_routing             = NULL,
 200         .cpu_present_to_apicid          = default_cpu_present_to_apicid,
 201         .apicid_to_cpu_present          = NULL,
 202         .check_phys_apicid_present      = default_check_phys_apicid_present,
 203         .phys_pkg_id                    = x2apic_phys_pkg_id,
 204
 205         .get_apic_id                    = x2apic_get_apic_id,
 206         .set_apic_id                    = x2apic_set_apic_id,
 207
 208         .calc_dest_apicid               = x2apic_calc_apicid,
 209
 210         .send_IPI                       = x2apic_send_IPI,
 211         .send_IPI_mask                  = x2apic_send_IPI_mask,
 212         .send_IPI_mask_allbutself       = x2apic_send_IPI_mask_allbutself,
 213         .send_IPI_allbutself            = x2apic_send_IPI_allbutself,
 214         .send_IPI_all                   = x2apic_send_IPI_all,
 215         .send_IPI_self                  = x2apic_send_IPI_self,
 216
 217         .inquire_remote_apic            = NULL,
 218
 219         .read                           = native_apic_msr_read,
 220         .write                          = native_apic_msr_write,
 221         .eoi_write                      = native_apic_msr_eoi_write,
 222         .icr_read                       = native_x2apic_icr_read,
 223         .icr_write                      = native_x2apic_icr_write,
 224         .wait_icr_idle                  = native_x2apic_wait_icr_idle,
 225         .safe_wait_icr_idle             = native_safe_x2apic_wait_icr_idle,
 226 };
 227
 228 apic_driver(apic_x2apic_cluster);