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// 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);
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