1 files changed, 156 insertions, 191 deletions

diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c
index c88baa4ff0e5..7db83212effb 100644
--- a/arch/x86/kernel/apic/x2apic_cluster.c
+++ b/arch/x86/kernel/apic/x2apic_cluster.c
@@ -1,75 +1,72 @@
-#include <linux/threads.h>
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/cpuhotplug.h>
 #include <linux/cpumask.h>
-#include <linux/string.h>
-#include <linux/kernel.h>
-#include <linux/ctype.h>
-#include <linux/init.h>
-#include <linux/dmar.h>
-#include <linux/cpu.h>
-
-#include <asm/smp.h>
-#include <asm/x2apic.h>
-
-static DEFINE_PER_CPU(u32, x86_cpu_to_logical_apicid);
-static DEFINE_PER_CPU(cpumask_var_t, cpus_in_cluster);
+#include <linux/slab.h>
+#include <linux/mm.h>
+
+#include <asm/apic.h>
+
+#include "local.h"
+
+#define apic_cluster(apicid) ((apicid) >> 4)
+
+/*
+ * __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 cpumask *, cluster_masks);
 
 static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
 {
 	return x2apic_enabled();
 }
 
-static inline u32 x2apic_cluster(int cpu)
+static void x2apic_send_IPI(int cpu, int vector)
 {
-	return per_cpu(x86_cpu_to_logical_apicid, cpu) >> 16;
+	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)
 {
-	struct cpumask *cpus_in_cluster_ptr;
-	struct cpumask *ipi_mask_ptr;
-	unsigned int cpu, this_cpu;
+	unsigned int cpu, clustercpu;
+	struct cpumask *tmpmsk;
 	unsigned long flags;
 	u32 dest;
 
-	x2apic_wrmsr_fence();
-
+	/* x2apic MSRs are special and need a special fence: */
+	weak_wrmsr_fence();
 	local_irq_save(flags);
 
-	this_cpu = smp_processor_id();
+	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);
 
-	/*
-	 * We are to modify mask, so we need an own copy
-	 * and be sure it's manipulated with irq off.
-	 */
-	ipi_mask_ptr = __raw_get_cpu_var(ipi_mask);
-	cpumask_copy(ipi_mask_ptr, mask);
+	/* Collapse cpus in a cluster so a single IPI per cluster is sent */
+	for_each_cpu(cpu, tmpmsk) {
+		struct cpumask *cmsk = per_cpu(cluster_masks, cpu);
 
-	/*
-	 * The idea is to send one IPI per cluster.
-	 */
-	for_each_cpu(cpu, ipi_mask_ptr) {
-		unsigned long i;
-
-		cpus_in_cluster_ptr = per_cpu(cpus_in_cluster, cpu);
 		dest = 0;
-
-		/* Collect cpus in cluster. */
-		for_each_cpu_and(i, ipi_mask_ptr, cpus_in_cluster_ptr) {
-			if (apic_dest == APIC_DEST_ALLINC || i != this_cpu)
-				dest |= per_cpu(x86_cpu_to_logical_apicid, i);
-		}
+		for_each_cpu_and(clustercpu, tmpmsk, cmsk)
+			dest |= x86_cpu_to_logical_apicid[clustercpu];
 
 		if (!dest)
 			continue;
 
-		__x2apic_send_IPI_dest(dest, vector, apic->dest_logical);
-		/*
-		 * Cluster sibling cpus should be discared now so
-		 * we would not send IPI them second time.
-		 */
-		cpumask_andnot(ipi_mask_ptr, ipi_mask_ptr, cpus_in_cluster_ptr);
+		__x2apic_send_IPI_dest(dest, vector, APIC_DEST_LOGICAL);
+		/* Remove cluster CPUs from tmpmask */
+		cpumask_andnot(tmpmsk, tmpmsk, cmsk);
 	}
 
 	local_irq_restore(flags);
@@ -86,211 +83,179 @@ 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)
+static u32 x2apic_calc_apicid(unsigned int cpu)
 {
-	__x2apic_send_IPI_mask(cpu_online_mask, vector, APIC_DEST_ALLBUT);
+	return x86_cpu_to_logical_apicid[cpu];
 }
 
-static void x2apic_send_IPI_all(int vector)
+static void init_x2apic_ldr(void)
 {
-	__x2apic_send_IPI_mask(cpu_online_mask, vector, APIC_DEST_ALLINC);
+	struct cpumask *cmsk = this_cpu_read(cluster_masks);
+
+	BUG_ON(!cmsk);
+
+	cpumask_set_cpu(smp_processor_id(), cmsk);
 }
 
-static int
-x2apic_cpu_mask_to_apicid_and(const struct cpumask *cpumask,
-			      const struct cpumask *andmask,
-			      unsigned int *apicid)
+/*
+ * As an optimisation during boot, set the cluster_mask for all present
+ * CPUs at once, to prevent each of them having to iterate over the others
+ * to find the existing cluster_mask.
+ */
+static void prefill_clustermask(struct cpumask *cmsk, unsigned int cpu, u32 cluster)
 {
-	u32 dest = 0;
-	u16 cluster;
-	int i;
+	int cpu_i;
 
-	for_each_cpu_and(i, cpumask, andmask) {
-		if (!cpumask_test_cpu(i, cpu_online_mask))
-			continue;
-		dest = per_cpu(x86_cpu_to_logical_apicid, i);
-		cluster = x2apic_cluster(i);
-		break;
-	}
-
-	if (!dest)
-		return -EINVAL;
+	for_each_present_cpu(cpu_i) {
+		struct cpumask **cpu_cmsk = &per_cpu(cluster_masks, cpu_i);
+		u32 apicid = apic->cpu_present_to_apicid(cpu_i);
 
-	for_each_cpu_and(i, cpumask, andmask) {
-		if (!cpumask_test_cpu(i, cpu_online_mask))
+		if (apicid == BAD_APICID || cpu_i == cpu || apic_cluster(apicid) != cluster)
 			continue;
-		if (cluster != x2apic_cluster(i))
-			continue;
-		dest |= per_cpu(x86_cpu_to_logical_apicid, i);
-	}
 
-	*apicid = dest;
+		if (WARN_ON_ONCE(*cpu_cmsk == cmsk))
+			continue;
 
-	return 0;
+		BUG_ON(*cpu_cmsk);
+		*cpu_cmsk = cmsk;
+	}
 }
 
-static void init_x2apic_ldr(void)
+static int alloc_clustermask(unsigned int cpu, u32 cluster, int node)
 {
-	unsigned int this_cpu = smp_processor_id();
-	unsigned int cpu;
+	struct cpumask *cmsk = NULL;
+	unsigned int cpu_i;
 
-	per_cpu(x86_cpu_to_logical_apicid, this_cpu) = apic_read(APIC_LDR);
+	/*
+	 * At boot time, the CPU present mask is stable. The cluster mask is
+	 * allocated for the first CPU in the cluster and propagated to all
+	 * present siblings in the cluster. If the cluster mask is already set
+	 * on entry to this function for a given CPU, there is nothing to do.
+	 */
+	if (per_cpu(cluster_masks, cpu))
+		return 0;
 
-	__cpu_set(this_cpu, per_cpu(cpus_in_cluster, this_cpu));
-	for_each_online_cpu(cpu) {
-		if (x2apic_cluster(this_cpu) != x2apic_cluster(cpu))
-			continue;
-		__cpu_set(this_cpu, per_cpu(cpus_in_cluster, cpu));
-		__cpu_set(cpu, per_cpu(cpus_in_cluster, this_cpu));
-	}
-}
+	if (system_state < SYSTEM_RUNNING)
+		goto alloc;
 
- /*
-  * At CPU state changes, update the x2apic cluster sibling info.
-  */
-static int __cpuinit
-update_clusterinfo(struct notifier_block *nfb, unsigned long action, void *hcpu)
-{
-	unsigned int this_cpu = (unsigned long)hcpu;
-	unsigned int cpu;
-	int err = 0;
-
-	switch (action) {
-	case CPU_UP_PREPARE:
-		if (!zalloc_cpumask_var(&per_cpu(cpus_in_cluster, this_cpu),
-					GFP_KERNEL)) {
-			err = -ENOMEM;
-		} else if (!zalloc_cpumask_var(&per_cpu(ipi_mask, this_cpu),
-					       GFP_KERNEL)) {
-			free_cpumask_var(per_cpu(cpus_in_cluster, this_cpu));
-			err = -ENOMEM;
-		}
-		break;
-	case CPU_UP_CANCELED:
-	case CPU_UP_CANCELED_FROZEN:
-	case CPU_DEAD:
-		for_each_online_cpu(cpu) {
-			if (x2apic_cluster(this_cpu) != x2apic_cluster(cpu))
-				continue;
-			__cpu_clear(this_cpu, per_cpu(cpus_in_cluster, cpu));
-			__cpu_clear(cpu, per_cpu(cpus_in_cluster, this_cpu));
+	/*
+	 * On post boot hotplug for a CPU which was not present at boot time,
+	 * iterate over all possible CPUs (even those which are not present
+	 * any more) to find any existing cluster mask.
+	 */
+	for_each_possible_cpu(cpu_i) {
+		u32 apicid = apic->cpu_present_to_apicid(cpu_i);
+
+		if (apicid != BAD_APICID && apic_cluster(apicid) == cluster) {
+			cmsk = per_cpu(cluster_masks, cpu_i);
+			/*
+			 * If the cluster is already initialized, just store
+			 * the mask and return. There's no need to propagate.
+			 */
+			if (cmsk) {
+				per_cpu(cluster_masks, cpu) = cmsk;
+				return 0;
+			}
 		}
-		free_cpumask_var(per_cpu(cpus_in_cluster, this_cpu));
-		free_cpumask_var(per_cpu(ipi_mask, this_cpu));
-		break;
 	}
+	/*
+	 * No CPU in the cluster has ever been initialized, so fall through to
+	 * the boot time code which will also populate the cluster mask for any
+	 * other CPU in the cluster which is (now) present.
+	 */
+alloc:
+	cmsk = kzalloc_node(sizeof(*cmsk), GFP_KERNEL, node);
+	if (!cmsk)
+		return -ENOMEM;
+	per_cpu(cluster_masks, cpu) = cmsk;
+	prefill_clustermask(cmsk, cpu, cluster);
 
-	return notifier_from_errno(err);
+	return 0;
 }
 
-static struct notifier_block __refdata x2apic_cpu_notifier = {
-	.notifier_call = update_clusterinfo,
-};
-
-static int x2apic_init_cpu_notifier(void)
+static int x2apic_prepare_cpu(unsigned int cpu)
 {
-	int cpu = smp_processor_id();
+	u32 phys_apicid = apic->cpu_present_to_apicid(cpu);
+	u32 cluster = apic_cluster(phys_apicid);
+	u32 logical_apicid = (cluster << 16) | (1 << (phys_apicid & 0xf));
+	int node = cpu_to_node(cpu);
 
-	zalloc_cpumask_var(&per_cpu(cpus_in_cluster, cpu), GFP_KERNEL);
-	zalloc_cpumask_var(&per_cpu(ipi_mask, cpu), GFP_KERNEL);
+	x86_cpu_to_logical_apicid[cpu] = logical_apicid;
 
-	BUG_ON(!per_cpu(cpus_in_cluster, cpu) || !per_cpu(ipi_mask, cpu));
+	if (alloc_clustermask(cpu, cluster, node) < 0)
+		return -ENOMEM;
 
-	__cpu_set(cpu, per_cpu(cpus_in_cluster, cpu));
-	register_hotcpu_notifier(&x2apic_cpu_notifier);
-	return 1;
-}
+	if (!zalloc_cpumask_var_node(&per_cpu(ipi_mask, cpu), GFP_KERNEL, node))
+		return -ENOMEM;
 
-static int x2apic_cluster_probe(void)
-{
-	if (x2apic_mode)
-		return x2apic_init_cpu_notifier();
-	else
-		return 0;
+	return 0;
 }
 
-static const struct cpumask *x2apic_cluster_target_cpus(void)
+static int x2apic_dead_cpu(unsigned int dead_cpu)
 {
-	return cpu_all_mask;
+	struct cpumask *cmsk = per_cpu(cluster_masks, dead_cpu);
+
+	if (cmsk)
+		cpumask_clear_cpu(dead_cpu, cmsk);
+	free_cpumask_var(per_cpu(ipi_mask, dead_cpu));
+	return 0;
 }
 
-/*
- * Each x2apic cluster is an allocation domain.
- */
-static void cluster_vector_allocation_domain(int cpu, struct cpumask *retmask,
-					     const struct cpumask *mask)
+static int x2apic_cluster_probe(void)
 {
-	/*
-	 * To minimize vector pressure, default case of boot, device bringup
-	 * etc will use a single cpu for the interrupt destination.
-	 *
-	 * On explicit migration requests coming from irqbalance etc,
-	 * interrupts will be routed to the x2apic cluster (cluster-id
-	 * derived from the first cpu in the mask) members specified
-	 * in the mask.
-	 */
-	if (mask == x2apic_cluster_target_cpus())
-		cpumask_copy(retmask, cpumask_of(cpu));
-	else
-		cpumask_and(retmask, mask, per_cpu(cpus_in_cluster, cpu));
+	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 = {
+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,
 
-	.irq_delivery_mode		= dest_LowestPrio,
-	.irq_dest_mode			= 1, /* logical */
+	.dest_mode_logical		= true,
 
-	.target_cpus			= x2apic_cluster_target_cpus,
 	.disable_esr			= 0,
-	.dest_logical			= APIC_DEST_LOGICAL,
-	.check_apicid_used		= NULL,
-	.check_apicid_present		= NULL,
 
-	.vector_allocation_domain	= cluster_vector_allocation_domain,
 	.init_apic_ldr			= init_x2apic_ldr,
-
-	.ioapic_phys_id_map		= NULL,
-	.setup_apic_routing		= NULL,
-	.multi_timer_check		= NULL,
 	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
-	.apicid_to_cpu_present		= NULL,
-	.setup_portio_remap		= NULL,
-	.check_phys_apicid_present	= default_check_phys_apicid_present,
-	.enable_apic_mode		= NULL,
-	.phys_pkg_id			= x2apic_phys_pkg_id,
-	.mps_oem_check			= NULL,
 
+	.max_apic_id			= UINT_MAX,
+	.x2apic_set_max_apicid		= true,
 	.get_apic_id			= x2apic_get_apic_id,
-	.set_apic_id			= x2apic_set_apic_id,
-	.apic_id_mask			= 0xFFFFFFFFu,
 
-	.cpu_mask_to_apicid_and		= x2apic_cpu_mask_to_apicid_and,
+	.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,
-
-	.trampoline_phys_low		= DEFAULT_TRAMPOLINE_PHYS_LOW,
-	.trampoline_phys_high		= DEFAULT_TRAMPOLINE_PHYS_HIGH,
-	.wait_for_init_deassert		= NULL,
-	.smp_callin_clear_local_apic	= NULL,
-	.inquire_remote_apic		= NULL,
+	.nmi_to_offline_cpu		= true,
 
 	.read				= native_apic_msr_read,
 	.write				= native_apic_msr_write,
-	.eoi_write			= native_apic_msr_eoi_write,
+	.eoi				= native_apic_msr_eoi,
 	.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);