[PATCH V11 3/3] powerpc/vphn: Better integrate vphn source code

From: Michael Bringmann
Date: Mon Aug 28 2017 - 20:33:18 EST


powerpc/vphn: Reorganize source code in order to better distinguish the
VPHN code from the NUMA code better, by moving relevant functions to
appropriate files.

Signed-off-by: Michael Bringmann <mwb@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/topology.h | 6
arch/powerpc/mm/numa.c | 550 +------------------------------
arch/powerpc/mm/vphn.c | 574 ++++++++++++++++++++++++++++++++
arch/powerpc/platforms/pseries/dlpar.c | 2
4 files changed, 583 insertions(+), 549 deletions(-)

diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index 85d6428..600e1c6 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -106,12 +106,6 @@ static inline int prrn_is_enabled(void)
#endif /* CONFIG_PPC_SPLPAR */
#endif /* CONFIG_HOTPLUG_CPU || CONFIG_NEED_MULTIPLE_NODES */

-#if defined(CONFIG_PPC_SPLPAR)
-extern void shared_topology_update(void);
-#else
-#define shared_topology_update() 0
-#endif /* CONFIG_PPC_SPLPAR */
-
#include <asm-generic/topology.h>

#ifdef CONFIG_SMP
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 2e8258a..a66f0da 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -42,8 +42,12 @@
#include <asm/setup.h>
#include <asm/vdso.h>

+#include "vphn.h"
+
static int numa_enabled = 1;

+bool topology_updates_enabled = true;
+
static char *cmdline __initdata;

static int numa_debug;
@@ -61,8 +65,7 @@
static int n_mem_addr_cells, n_mem_size_cells;
static int form1_affinity;

-#define MAX_DISTANCE_REF_POINTS 4
-static int distance_ref_points_depth;
+int distance_ref_points_depth;
static const __be32 *distance_ref_points;
static int distance_lookup_table[MAX_NUMNODES][MAX_DISTANCE_REF_POINTS];

@@ -143,12 +146,12 @@ static void reset_numa_cpu_lookup_table(void)
numa_cpu_lookup_table[cpu] = -1;
}

-static void update_numa_cpu_lookup_table(unsigned int cpu, int node)
+void update_numa_cpu_lookup_table(unsigned int cpu, int node)
{
numa_cpu_lookup_table[cpu] = node;
}

-static void map_cpu_to_node(int cpu, int node)
+void map_cpu_to_node(int cpu, int node)
{
update_numa_cpu_lookup_table(cpu, node);

@@ -159,7 +162,7 @@ static void map_cpu_to_node(int cpu, int node)
}

#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_PPC_SPLPAR)
-static void unmap_cpu_from_node(unsigned long cpu)
+void unmap_cpu_from_node(unsigned long cpu)
{
int node = numa_cpu_lookup_table[cpu];

@@ -234,7 +237,7 @@ static void initialize_distance_lookup_table(int nid,
/* Returns nid in the range [0..MAX_NUMNODES-1], or -1 if no useful numa
* info is found.
*/
-static int associativity_to_nid(const __be32 *associativity)
+int associativity_to_nid(const __be32 *associativity)
{
int nid = -1;

@@ -1001,8 +1004,6 @@ static int __init early_numa(char *p)
}
early_param("numa", early_numa);

-static bool topology_updates_enabled = true;
-
static int __init early_topology_updates(char *p)
{
if (!p)
@@ -1179,536 +1180,3 @@ u64 memory_hotplug_max(void)
return max(hot_add_drconf_memory_max(), memblock_end_of_DRAM());
}
#endif /* CONFIG_MEMORY_HOTPLUG */
-
-/* Virtual Processor Home Node (VPHN) support */
-#ifdef CONFIG_PPC_SPLPAR
-
-#include "vphn.h"
-
-struct topology_update_data {
- struct topology_update_data *next;
- unsigned int cpu;
- int old_nid;
- int new_nid;
-};
-
-#define TOPOLOGY_DEF_TIMER_SECS 60
-
-static u8 vphn_cpu_change_counts[NR_CPUS][MAX_DISTANCE_REF_POINTS];
-static cpumask_t cpu_associativity_changes_mask;
-static int vphn_enabled;
-static int prrn_enabled;
-static void reset_topology_timer(void);
-static int topology_timer_secs = TOPOLOGY_DEF_TIMER_SECS;
-static int topology_inited;
-static int topology_update_needed;
-
-/*
- * Change polling interval for associativity changes.
- */
-int timed_topology_update(int nsecs)
-{
- if (nsecs > 0)
- topology_timer_secs = nsecs;
- else
- topology_timer_secs = TOPOLOGY_DEF_TIMER_SECS;
-
- if (vphn_enabled)
- reset_topology_timer();
-
- return 0;
-}
-
-/*
- * Store the current values of the associativity change counters in the
- * hypervisor.
- */
-static void setup_cpu_associativity_change_counters(void)
-{
- int cpu;
-
- /* The VPHN feature supports a maximum of 8 reference points */
- BUILD_BUG_ON(MAX_DISTANCE_REF_POINTS > 8);
-
- for_each_possible_cpu(cpu) {
- int i;
- u8 *counts = vphn_cpu_change_counts[cpu];
- volatile u8 *hypervisor_counts = lppaca[cpu].vphn_assoc_counts;
-
- for (i = 0; i < distance_ref_points_depth; i++)
- counts[i] = hypervisor_counts[i];
- }
-}
-
-/*
- * The hypervisor maintains a set of 8 associativity change counters in
- * the VPA of each cpu that correspond to the associativity levels in the
- * ibm,associativity-reference-points property. When an associativity
- * level changes, the corresponding counter is incremented.
- *
- * Set a bit in cpu_associativity_changes_mask for each cpu whose home
- * node associativity levels have changed.
- *
- * Returns the number of cpus with unhandled associativity changes.
- */
-static int update_cpu_associativity_changes_mask(void)
-{
- int cpu;
- cpumask_t *changes = &cpu_associativity_changes_mask;
-
- for_each_possible_cpu(cpu) {
- int i, changed = 0;
- u8 *counts = vphn_cpu_change_counts[cpu];
- volatile u8 *hypervisor_counts = lppaca[cpu].vphn_assoc_counts;
-
- for (i = 0; i < distance_ref_points_depth; i++) {
- if (hypervisor_counts[i] != counts[i]) {
- counts[i] = hypervisor_counts[i];
- changed = 1;
- }
- }
- if (changed) {
- cpumask_or(changes, changes, cpu_sibling_mask(cpu));
- cpu = cpu_last_thread_sibling(cpu);
- }
- }
-
- return cpumask_weight(changes);
-}
-
-/*
- * Retrieve the new associativity information for a virtual processor's
- * home node.
- */
-static long hcall_vphn(unsigned long cpu, __be32 *associativity)
-{
- long rc;
- long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
- u64 flags = 1;
- int hwcpu = get_hard_smp_processor_id(cpu);
-
- rc = plpar_hcall9(H_HOME_NODE_ASSOCIATIVITY, retbuf, flags, hwcpu);
- vphn_unpack_associativity(retbuf, associativity);
-
- return rc;
-}
-
-static long vphn_get_associativity(unsigned long cpu,
- __be32 *associativity)
-{
- long rc;
-
- rc = hcall_vphn(cpu, associativity);
-
- switch (rc) {
- case H_FUNCTION:
- printk(KERN_INFO
- "VPHN is not supported. Disabling polling...\n");
- stop_topology_update();
- break;
- case H_HARDWARE:
- printk(KERN_ERR
- "hcall_vphn() experienced a hardware fault "
- "preventing VPHN. Disabling polling...\n");
- stop_topology_update();
- break;
- case H_SUCCESS:
- printk(KERN_INFO
- "VPHN hcall succeeded. Reset polling...\n");
- timed_topology_update(0);
- break;
- }
-
- return rc;
-}
-
-/*
- * Update the CPU maps and sysfs entries for a single CPU when its NUMA
- * characteristics change. This function doesn't perform any locking and is
- * only safe to call from stop_machine().
- */
-static int update_cpu_topology(void *data)
-{
- struct topology_update_data *update;
- unsigned long cpu;
-
- if (!data)
- return -EINVAL;
-
- cpu = smp_processor_id();
-
- for (update = data; update; update = update->next) {
- int new_nid = update->new_nid;
- if (cpu != update->cpu)
- continue;
-
- unmap_cpu_from_node(cpu);
- map_cpu_to_node(cpu, new_nid);
- set_cpu_numa_node(cpu, new_nid);
- set_cpu_numa_mem(cpu, local_memory_node(new_nid));
- vdso_getcpu_init();
- }
-
- return 0;
-}
-
-static int update_lookup_table(void *data)
-{
- struct topology_update_data *update;
-
- if (!data)
- return -EINVAL;
-
- /*
- * Upon topology update, the numa-cpu lookup table needs to be updated
- * for all threads in the core, including offline CPUs, to ensure that
- * future hotplug operations respect the cpu-to-node associativity
- * properly.
- */
- for (update = data; update; update = update->next) {
- int nid, base, j;
-
- nid = update->new_nid;
- base = cpu_first_thread_sibling(update->cpu);
-
- for (j = 0; j < threads_per_core; j++) {
- update_numa_cpu_lookup_table(base + j, nid);
- }
- }
-
- return 0;
-}
-
-/*
- * Update the node maps and sysfs entries for each cpu whose home node
- * has changed. Returns 1 when the topology has changed, and 0 otherwise.
- *
- * cpus_locked says whether we already hold cpu_hotplug_lock.
- */
-int numa_update_cpu_topology(bool cpus_locked)
-{
- unsigned int cpu, sibling, changed = 0;
- struct topology_update_data *updates, *ud;
- __be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
- cpumask_t updated_cpus;
- struct device *dev;
- int weight, new_nid, i = 0;
-
- if (!prrn_enabled && !vphn_enabled) {
- if (!topology_inited)
- topology_update_needed = 1;
- return 0;
- }
-
- weight = cpumask_weight(&cpu_associativity_changes_mask);
- if (!weight)
- return 0;
-
- updates = kzalloc(weight * (sizeof(*updates)), GFP_KERNEL);
- if (!updates)
- return 0;
-
- cpumask_clear(&updated_cpus);
-
- for_each_cpu(cpu, &cpu_associativity_changes_mask) {
- /*
- * If siblings aren't flagged for changes, updates list
- * will be too short. Skip on this update and set for next
- * update.
- */
- if (!cpumask_subset(cpu_sibling_mask(cpu),
- &cpu_associativity_changes_mask)) {
- pr_info("Sibling bits not set for associativity "
- "change, cpu%d\n", cpu);
- cpumask_or(&cpu_associativity_changes_mask,
- &cpu_associativity_changes_mask,
- cpu_sibling_mask(cpu));
- cpu = cpu_last_thread_sibling(cpu);
- continue;
- }
-
- /* Use associativity from first thread for all siblings */
- vphn_get_associativity(cpu, associativity);
- new_nid = associativity_to_nid(associativity);
- if (new_nid < 0 || !node_online(new_nid))
- new_nid = first_online_node;
-
- if (new_nid == numa_cpu_lookup_table[cpu]) {
- cpumask_andnot(&cpu_associativity_changes_mask,
- &cpu_associativity_changes_mask,
- cpu_sibling_mask(cpu));
- pr_info("Assoc chg gives same node %d for cpu%d\n",
- new_nid, cpu);
- cpu = cpu_last_thread_sibling(cpu);
- continue;
- }
-
- for_each_cpu(sibling, cpu_sibling_mask(cpu)) {
- ud = &updates[i++];
- ud->cpu = sibling;
- ud->new_nid = new_nid;
- ud->old_nid = numa_cpu_lookup_table[sibling];
- cpumask_set_cpu(sibling, &updated_cpus);
- if (i < weight)
- ud->next = &updates[i];
- else
- ud->next = NULL;
- }
- cpu = cpu_last_thread_sibling(cpu);
- }
-
- pr_debug("Topology update for the following CPUs:\n");
- if (cpumask_weight(&updated_cpus)) {
- for (ud = &updates[0]; ud; ud = ud->next) {
- pr_debug("cpu %d moving from node %d "
- "to %d\n", ud->cpu,
- ud->old_nid, ud->new_nid);
- }
- }
-
- /*
- * In cases where we have nothing to update (because the updates list
- * is too short or because the new topology is same as the old one),
- * skip invoking update_cpu_topology() via stop-machine(). This is
- * necessary (and not just a fast-path optimization) since stop-machine
- * can end up electing a random CPU to run update_cpu_topology(), and
- * thus trick us into setting up incorrect cpu-node mappings (since
- * 'updates' is kzalloc()'ed).
- *
- * And for the similar reason, we will skip all the following updating.
- */
- if (!cpumask_weight(&updated_cpus))
- goto out;
-
- if (cpus_locked)
- stop_machine_cpuslocked(update_cpu_topology, &updates[0],
- &updated_cpus);
- else
- stop_machine(update_cpu_topology, &updates[0], &updated_cpus);
-
- /*
- * Update the numa-cpu lookup table with the new mappings, even for
- * offline CPUs. It is best to perform this update from the stop-
- * machine context.
- */
- if (cpus_locked)
- stop_machine_cpuslocked(update_lookup_table, &updates[0],
- cpumask_of(raw_smp_processor_id()));
- else
- stop_machine(update_lookup_table, &updates[0],
- cpumask_of(raw_smp_processor_id()));
-
- for (ud = &updates[0]; ud; ud = ud->next) {
- unregister_cpu_under_node(ud->cpu, ud->old_nid);
- register_cpu_under_node(ud->cpu, ud->new_nid);
-
- dev = get_cpu_device(ud->cpu);
- if (dev)
- kobject_uevent(&dev->kobj, KOBJ_CHANGE);
- cpumask_clear_cpu(ud->cpu, &cpu_associativity_changes_mask);
- changed = 1;
- }
-
-out:
- kfree(updates);
- topology_update_needed = 0;
- return changed;
-}
-
-int arch_update_cpu_topology(void)
-{
- lockdep_assert_cpus_held();
- return numa_update_cpu_topology(true);
-}
-
-static void topology_work_fn(struct work_struct *work)
-{
- rebuild_sched_domains();
-}
-static DECLARE_WORK(topology_work, topology_work_fn);
-
-static void topology_schedule_update(void)
-{
- schedule_work(&topology_work);
-}
-
-void shared_topology_update(void)
-{
- if (firmware_has_feature(FW_FEATURE_VPHN) &&
- lppaca_shared_proc(get_lppaca()))
- topology_schedule_update();
-}
-EXPORT_SYMBOL(shared_topology_update);
-
-static void topology_timer_fn(unsigned long ignored)
-{
- if (prrn_enabled && cpumask_weight(&cpu_associativity_changes_mask))
- topology_schedule_update();
- else if (vphn_enabled) {
- if (update_cpu_associativity_changes_mask() > 0)
- topology_schedule_update();
- reset_topology_timer();
- }
-}
-static struct timer_list topology_timer =
- TIMER_INITIALIZER(topology_timer_fn, 0, 0);
-
-static void reset_topology_timer(void)
-{
- topology_timer.data = 0;
- topology_timer.expires = jiffies + topology_timer_secs * HZ;
- mod_timer(&topology_timer, topology_timer.expires);
-}
-
-#ifdef CONFIG_SMP
-
-static void stage_topology_update(int core_id)
-{
- cpumask_or(&cpu_associativity_changes_mask,
- &cpu_associativity_changes_mask, cpu_sibling_mask(core_id));
- reset_topology_timer();
-}
-
-static int dt_update_callback(struct notifier_block *nb,
- unsigned long action, void *data)
-{
- struct of_reconfig_data *update = data;
- int rc = NOTIFY_DONE;
-
- switch (action) {
- case OF_RECONFIG_UPDATE_PROPERTY:
- if (!of_prop_cmp(update->dn->type, "cpu") &&
- !of_prop_cmp(update->prop->name, "ibm,associativity")) {
- u32 core_id;
- of_property_read_u32(update->dn, "reg", &core_id);
- stage_topology_update(core_id);
- rc = NOTIFY_OK;
- }
- break;
- }
-
- return rc;
-}
-
-static struct notifier_block dt_update_nb = {
- .notifier_call = dt_update_callback,
-};
-
-#endif
-
-/*
- * Start polling for associativity changes.
- */
-int start_topology_update(void)
-{
- int rc = 0;
-
- if (firmware_has_feature(FW_FEATURE_PRRN)) {
- if (!prrn_enabled) {
- prrn_enabled = 1;
-#ifdef CONFIG_SMP
- rc = of_reconfig_notifier_register(&dt_update_nb);
-#endif
- }
- }
- if (firmware_has_feature(FW_FEATURE_VPHN) &&
- lppaca_shared_proc(get_lppaca())) {
- if (!vphn_enabled) {
- vphn_enabled = 1;
- setup_cpu_associativity_change_counters();
- init_timer_deferrable(&topology_timer);
- reset_topology_timer();
- }
- }
-
- return rc;
-}
-
-/*
- * Disable polling for VPHN associativity changes.
- */
-int stop_topology_update(void)
-{
- int rc = 0;
-
- if (prrn_enabled) {
- prrn_enabled = 0;
-#ifdef CONFIG_SMP
- rc = of_reconfig_notifier_unregister(&dt_update_nb);
-#endif
- }
- if (vphn_enabled) {
- vphn_enabled = 0;
- rc = del_timer_sync(&topology_timer);
- }
-
- return rc;
-}
-
-int prrn_is_enabled(void)
-{
- return prrn_enabled;
-}
-
-static int topology_read(struct seq_file *file, void *v)
-{
- if (vphn_enabled || prrn_enabled)
- seq_puts(file, "on\n");
- else
- seq_puts(file, "off\n");
-
- return 0;
-}
-
-static int topology_open(struct inode *inode, struct file *file)
-{
- return single_open(file, topology_read, NULL);
-}
-
-static ssize_t topology_write(struct file *file, const char __user *buf,
- size_t count, loff_t *off)
-{
- char kbuf[4]; /* "on" or "off" plus null. */
- int read_len;
-
- read_len = count < 3 ? count : 3;
- if (copy_from_user(kbuf, buf, read_len))
- return -EINVAL;
-
- kbuf[read_len] = '\0';
-
- if (!strncmp(kbuf, "on", 2))
- start_topology_update();
- else if (!strncmp(kbuf, "off", 3))
- stop_topology_update();
- else
- return -EINVAL;
-
- return count;
-}
-
-static const struct file_operations topology_ops = {
- .read = seq_read,
- .write = topology_write,
- .open = topology_open,
- .release = single_release
-};
-
-static int topology_update_init(void)
-{
- /* Do not poll for changes if disabled at boot */
- if (topology_updates_enabled)
- start_topology_update();
-
- if (!proc_create("powerpc/topology_updates", 0644, NULL, &topology_ops))
- return -ENOMEM;
-
- topology_inited = 1;
- if (topology_update_needed)
- bitmap_fill(cpumask_bits(&cpu_associativity_changes_mask),
- nr_cpumask_bits);
-
- return 0;
-}
-device_initcall(topology_update_init);
-#endif /* CONFIG_PPC_SPLPAR */
diff --git a/arch/powerpc/mm/vphn.c b/arch/powerpc/mm/vphn.c
index 5f8ef50..3859c9c 100644
--- a/arch/powerpc/mm/vphn.c
+++ b/arch/powerpc/mm/vphn.c
@@ -1,6 +1,70 @@
+/*
+ * pSeries VPHN support
+ *
+ * Copyright (C) 2015 Greg Kurz <gkurz@xxxxxxxxxxxxxxxxxx>, IBM
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#define pr_fmt(fmt) "vphn: " fmt
+
+#include <linux/threads.h>
+#include <linux/bootmem.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/export.h>
+#include <linux/nodemask.h>
+#include <linux/cpu.h>
+#include <linux/notifier.h>
+#include <linux/memblock.h>
+#include <linux/of.h>
+#include <linux/pfn.h>
+#include <linux/cpuset.h>
+#include <linux/node.h>
+#include <linux/stop_machine.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <asm/cputhreads.h>
+#include <asm/sparsemem.h>
+#include <asm/prom.h>
+#include <asm/smp.h>
+#include <asm/cputhreads.h>
+#include <asm/topology.h>
+#include <asm/firmware.h>
+#include <asm/paca.h>
+#include <asm/hvcall.h>
+#include <asm/setup.h>
+#include <asm/vdso.h>
#include <asm/byteorder.h>
+
+/* Virtual Processor Home Node (VPHN) support */
+
#include "vphn.h"

+struct topology_update_data {
+ struct topology_update_data *next;
+ unsigned int cpu;
+ int old_nid;
+ int new_nid;
+};
+
+#define TOPOLOGY_DEF_TIMER_SECS 60
+
+static u8 vphn_cpu_change_counts[NR_CPUS][MAX_DISTANCE_REF_POINTS];
+static cpumask_t cpu_associativity_changes_mask;
+static int vphn_enabled;
+static int prrn_enabled;
+static void reset_topology_timer(void);
+static int topology_timer_secs = TOPOLOGY_DEF_TIMER_SECS;
+static int topology_inited;
+static int topology_update_needed;
+
/*
* The associativity domain numbers are returned from the hypervisor as a
* stream of mixed 16-bit and 32-bit fields. The stream is terminated by the
@@ -68,3 +132,513 @@ int vphn_unpack_associativity(const long *packed, __be32 *unpacked)

return nr_assoc_doms;
}
+
+/*
+ * Change polling interval for associativity changes.
+ */
+int timed_topology_update(int nsecs)
+{
+ if (nsecs > 0)
+ topology_timer_secs = nsecs;
+ else
+ topology_timer_secs = TOPOLOGY_DEF_TIMER_SECS;
+
+ if (vphn_enabled)
+ reset_topology_timer();
+
+ return 0;
+}
+
+/*
+ * Store the current values of the associativity change counters in the
+ * hypervisor.
+ */
+static void setup_cpu_associativity_change_counters(void)
+{
+ int cpu;
+
+ /* The VPHN feature supports a maximum of 8 reference points */
+ BUILD_BUG_ON(MAX_DISTANCE_REF_POINTS > 8);
+
+ for_each_possible_cpu(cpu) {
+ int i;
+ u8 *counts = vphn_cpu_change_counts[cpu];
+ volatile u8 *hypervisor_counts = lppaca[cpu].vphn_assoc_counts;
+
+ for (i = 0; i < distance_ref_points_depth; i++)
+ counts[i] = hypervisor_counts[i];
+ }
+}
+
+/*
+ * The hypervisor maintains a set of 8 associativity change counters in
+ * the VPA of each cpu that correspond to the associativity levels in the
+ * ibm,associativity-reference-points property. When an associativity
+ * level changes, the corresponding counter is incremented.
+ *
+ * Set a bit in cpu_associativity_changes_mask for each cpu whose home
+ * node associativity levels have changed.
+ *
+ * Returns the number of cpus with unhandled associativity changes.
+ */
+static int update_cpu_associativity_changes_mask(void)
+{
+ int cpu;
+ cpumask_t *changes = &cpu_associativity_changes_mask;
+
+ for_each_possible_cpu(cpu) {
+ int i, changed = 0;
+ u8 *counts = vphn_cpu_change_counts[cpu];
+ volatile u8 *hypervisor_counts = lppaca[cpu].vphn_assoc_counts;
+
+ for (i = 0; i < distance_ref_points_depth; i++) {
+ if (hypervisor_counts[i] != counts[i]) {
+ counts[i] = hypervisor_counts[i];
+ changed = 1;
+ }
+ }
+ if (changed) {
+ cpumask_or(changes, changes, cpu_sibling_mask(cpu));
+ cpu = cpu_last_thread_sibling(cpu);
+ }
+ }
+
+ return cpumask_weight(changes);
+}
+
+/*
+ * Retrieve the new associativity information for a virtual processor's
+ * home node.
+ */
+static long hcall_vphn(unsigned long cpu, __be32 *associativity)
+{
+ long rc;
+ long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
+ u64 flags = 1;
+ int hwcpu = get_hard_smp_processor_id(cpu);
+
+ rc = plpar_hcall9(H_HOME_NODE_ASSOCIATIVITY, retbuf, flags, hwcpu);
+ vphn_unpack_associativity(retbuf, associativity);
+
+ return rc;
+}
+
+static long vphn_get_associativity(unsigned long cpu,
+ __be32 *associativity)
+{
+ long rc;
+
+ rc = hcall_vphn(cpu, associativity);
+
+ switch (rc) {
+ case H_FUNCTION:
+ printk(KERN_INFO
+ "VPHN is not supported. Disabling polling...\n");
+ stop_topology_update();
+ break;
+ case H_HARDWARE:
+ printk(KERN_ERR
+ "hcall_vphn() experienced a hardware fault "
+ "preventing VPHN. Disabling polling...\n");
+ stop_topology_update();
+ break;
+ case H_SUCCESS:
+ printk(KERN_INFO
+ "VPHN hcall succeeded. Reset polling...\n");
+ timed_topology_update(0);
+ break;
+ }
+
+ return rc;
+}
+
+/*
+ * Update the CPU maps and sysfs entries for a single CPU when its NUMA
+ * characteristics change. This function doesn't perform any locking and is
+ * only safe to call from stop_machine().
+ */
+static int update_cpu_topology(void *data)
+{
+ struct topology_update_data *update;
+ unsigned long cpu;
+
+ if (!data)
+ return -EINVAL;
+
+ cpu = smp_processor_id();
+
+ for (update = data; update; update = update->next) {
+ int new_nid = update->new_nid;
+ if (cpu != update->cpu)
+ continue;
+
+ unmap_cpu_from_node(cpu);
+ map_cpu_to_node(cpu, new_nid);
+ set_cpu_numa_node(cpu, new_nid);
+ set_cpu_numa_mem(cpu, local_memory_node(new_nid));
+ vdso_getcpu_init();
+ }
+
+ return 0;
+}
+
+static int update_lookup_table(void *data)
+{
+ struct topology_update_data *update;
+
+ if (!data)
+ return -EINVAL;
+
+ /*
+ * Upon topology update, the numa-cpu lookup table needs to be updated
+ * for all threads in the core, including offline CPUs, to ensure that
+ * future hotplug operations respect the cpu-to-node associativity
+ * properly.
+ */
+ for (update = data; update; update = update->next) {
+ int nid, base, j;
+
+ nid = update->new_nid;
+ base = cpu_first_thread_sibling(update->cpu);
+
+ for (j = 0; j < threads_per_core; j++) {
+ update_numa_cpu_lookup_table(base + j, nid);
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Update the node maps and sysfs entries for each cpu whose home node
+ * has changed. Returns 1 when the topology has changed, and 0 otherwise.
+ *
+ * cpus_locked says whether we already hold cpu_hotplug_lock.
+ */
+int numa_update_cpu_topology(bool cpus_locked)
+{
+ unsigned int cpu, sibling, changed = 0;
+ struct topology_update_data *updates, *ud;
+ __be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
+ cpumask_t updated_cpus;
+ struct device *dev;
+ int weight, new_nid, i = 0;
+
+ if (!prrn_enabled && !vphn_enabled) {
+ if (!topology_inited)
+ topology_update_needed = 1;
+ return 0;
+ }
+
+ weight = cpumask_weight(&cpu_associativity_changes_mask);
+ if (!weight)
+ return 0;
+
+ updates = kzalloc(weight * (sizeof(*updates)), GFP_KERNEL);
+ if (!updates)
+ return 0;
+
+ cpumask_clear(&updated_cpus);
+
+ for_each_cpu(cpu, &cpu_associativity_changes_mask) {
+ /*
+ * If siblings aren't flagged for changes, updates list
+ * will be too short. Skip on this update and set for next
+ * update.
+ */
+ if (!cpumask_subset(cpu_sibling_mask(cpu),
+ &cpu_associativity_changes_mask)) {
+ pr_info("Sibling bits not set for associativity "
+ "change, cpu%d\n", cpu);
+ cpumask_or(&cpu_associativity_changes_mask,
+ &cpu_associativity_changes_mask,
+ cpu_sibling_mask(cpu));
+ cpu = cpu_last_thread_sibling(cpu);
+ continue;
+ }
+
+ /* Use associativity from first thread for all siblings */
+ vphn_get_associativity(cpu, associativity);
+ new_nid = associativity_to_nid(associativity);
+ if (new_nid < 0 || !node_online(new_nid))
+ new_nid = first_online_node;
+
+ if (new_nid == numa_cpu_lookup_table[cpu]) {
+ cpumask_andnot(&cpu_associativity_changes_mask,
+ &cpu_associativity_changes_mask,
+ cpu_sibling_mask(cpu));
+ pr_info("Assoc chg gives same node %d for cpu%d\n",
+ new_nid, cpu);
+ cpu = cpu_last_thread_sibling(cpu);
+ continue;
+ }
+
+ for_each_cpu(sibling, cpu_sibling_mask(cpu)) {
+ ud = &updates[i++];
+ ud->cpu = sibling;
+ ud->new_nid = new_nid;
+ ud->old_nid = numa_cpu_lookup_table[sibling];
+ cpumask_set_cpu(sibling, &updated_cpus);
+ if (i < weight)
+ ud->next = &updates[i];
+ }
+ cpu = cpu_last_thread_sibling(cpu);
+ }
+
+ if (i)
+ updates[i-1].next = NULL;
+
+ pr_debug("Topology update for the following CPUs:\n");
+ if (cpumask_weight(&updated_cpus)) {
+ for (ud = &updates[0]; ud; ud = ud->next) {
+ pr_debug("cpu %d moving from node %d "
+ "to %d\n", ud->cpu,
+ ud->old_nid, ud->new_nid);
+ }
+ }
+
+ /*
+ * In cases where we have nothing to update (because the updates list
+ * is too short or because the new topology is same as the old one),
+ * skip invoking update_cpu_topology() via stop-machine(). This is
+ * necessary (and not just a fast-path optimization) since stop-machine
+ * can end up electing a random CPU to run update_cpu_topology(), and
+ * thus trick us into setting up incorrect cpu-node mappings (since
+ * 'updates' is kzalloc()'ed).
+ *
+ * And for the similar reason, we will skip all the following updating.
+ */
+ if (!cpumask_weight(&updated_cpus))
+ goto out;
+
+ if (cpus_locked)
+ stop_machine_cpuslocked(update_cpu_topology, &updates[0],
+ &updated_cpus);
+ else
+ stop_machine(update_cpu_topology, &updates[0], &updated_cpus);
+
+ /*
+ * Update the numa-cpu lookup table with the new mappings, even for
+ * offline CPUs. It is best to perform this update from the stop-
+ * machine context.
+ */
+ if (cpus_locked)
+ stop_machine_cpuslocked(update_lookup_table, &updates[0],
+ cpumask_of(raw_smp_processor_id()));
+ else
+ stop_machine(update_lookup_table, &updates[0],
+ cpumask_of(raw_smp_processor_id()));
+
+ for (ud = &updates[0]; ud; ud = ud->next) {
+ unregister_cpu_under_node(ud->cpu, ud->old_nid);
+ register_cpu_under_node(ud->cpu, ud->new_nid);
+
+ dev = get_cpu_device(ud->cpu);
+ if (dev)
+ kobject_uevent(&dev->kobj, KOBJ_CHANGE);
+ cpumask_clear_cpu(ud->cpu, &cpu_associativity_changes_mask);
+ changed = 1;
+ }
+
+out:
+ kfree(updates);
+ topology_update_needed = 0;
+ return changed;
+}
+
+int arch_update_cpu_topology(void)
+{
+ lockdep_assert_cpus_held();
+ return numa_update_cpu_topology(true);
+}
+
+static void topology_work_fn(struct work_struct *work)
+{
+ rebuild_sched_domains();
+}
+static DECLARE_WORK(topology_work, topology_work_fn);
+
+static void topology_schedule_update(void)
+{
+ schedule_work(&topology_work);
+}
+
+static void shared_topology_update(void)
+{
+ if (firmware_has_feature(FW_FEATURE_VPHN) &&
+ lppaca_shared_proc(get_lppaca()))
+ topology_schedule_update();
+}
+
+static void topology_timer_fn(unsigned long ignored)
+{
+ if (prrn_enabled && cpumask_weight(&cpu_associativity_changes_mask))
+ topology_schedule_update();
+ else if (vphn_enabled) {
+ if (update_cpu_associativity_changes_mask() > 0)
+ topology_schedule_update();
+ reset_topology_timer();
+ }
+}
+static struct timer_list topology_timer =
+ TIMER_INITIALIZER(topology_timer_fn, 0, 0);
+
+static void reset_topology_timer(void)
+{
+ topology_timer.data = 0;
+ topology_timer.expires = jiffies + topology_timer_secs * HZ;
+ mod_timer(&topology_timer, topology_timer.expires);
+}
+
+#ifdef CONFIG_SMP
+
+static void stage_topology_update(int core_id)
+{
+ cpumask_or(&cpu_associativity_changes_mask,
+ &cpu_associativity_changes_mask, cpu_sibling_mask(core_id));
+ reset_topology_timer();
+}
+
+static int dt_update_callback(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct of_reconfig_data *update = data;
+ int rc = NOTIFY_DONE;
+
+ switch (action) {
+ case OF_RECONFIG_UPDATE_PROPERTY:
+ if (!of_prop_cmp(update->dn->type, "cpu") &&
+ !of_prop_cmp(update->prop->name, "ibm,associativity")) {
+ u32 core_id;
+ of_property_read_u32(update->dn, "reg", &core_id);
+ stage_topology_update(core_id);
+ rc = NOTIFY_OK;
+ }
+ break;
+ }
+
+ return rc;
+}
+
+static struct notifier_block dt_update_nb = {
+ .notifier_call = dt_update_callback,
+};
+
+#endif
+
+/*
+ * Start polling for associativity changes.
+ */
+int start_topology_update(void)
+{
+ int rc = 0;
+
+ if (firmware_has_feature(FW_FEATURE_PRRN)) {
+ if (!prrn_enabled) {
+ prrn_enabled = 1;
+#ifdef CONFIG_SMP
+ rc = of_reconfig_notifier_register(&dt_update_nb);
+#endif
+ }
+ }
+ if (firmware_has_feature(FW_FEATURE_VPHN) &&
+ lppaca_shared_proc(get_lppaca())) {
+ if (!vphn_enabled) {
+ vphn_enabled = 1;
+ setup_cpu_associativity_change_counters();
+ init_timer_deferrable(&topology_timer);
+ reset_topology_timer();
+ }
+ }
+
+ return rc;
+}
+
+/*
+ * Disable polling for VPHN associativity changes.
+ */
+int stop_topology_update(void)
+{
+ int rc = 0;
+
+ if (prrn_enabled) {
+ prrn_enabled = 0;
+#ifdef CONFIG_SMP
+ rc = of_reconfig_notifier_unregister(&dt_update_nb);
+#endif
+ }
+ if (vphn_enabled) {
+ vphn_enabled = 0;
+ rc = del_timer_sync(&topology_timer);
+ }
+
+ return rc;
+}
+
+int prrn_is_enabled(void)
+{
+ return prrn_enabled;
+}
+
+static int topology_read(struct seq_file *file, void *v)
+{
+ if (vphn_enabled || prrn_enabled)
+ seq_puts(file, "on\n");
+ else
+ seq_puts(file, "off\n");
+
+ return 0;
+}
+
+static int topology_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, topology_read, NULL);
+}
+
+static ssize_t topology_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *off)
+{
+ char kbuf[4]; /* "on" or "off" plus null. */
+ int read_len;
+
+ read_len = count < 3 ? count : 3;
+ if (copy_from_user(kbuf, buf, read_len))
+ return -EINVAL;
+
+ kbuf[read_len] = '\0';
+
+ if (!strncmp(kbuf, "on", 2))
+ start_topology_update();
+ else if (!strncmp(kbuf, "off", 3))
+ stop_topology_update();
+ else
+ return -EINVAL;
+
+ return count;
+}
+
+static const struct file_operations topology_ops = {
+ .read = seq_read,
+ .write = topology_write,
+ .open = topology_open,
+ .release = single_release
+};
+
+static int topology_update_init(void)
+{
+ /* Do not poll for changes if disabled at boot */
+ if (topology_updates_enabled)
+ start_topology_update();
+
+ if (!proc_create("powerpc/topology_updates", 0644, NULL, &topology_ops))
+ return -ENOMEM;
+
+ topology_inited = 1;
+ if (topology_update_needed)
+ bitmap_fill(cpumask_bits(&cpu_associativity_changes_mask),
+ nr_cpumask_bits);
+
+ return 0;
+}
+device_initcall(topology_update_init);
+#endif /* CONFIG_PPC_SPLPAR */
diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
index ba9a4a0..3918769 100644
--- a/arch/powerpc/platforms/pseries/dlpar.c
+++ b/arch/powerpc/platforms/pseries/dlpar.c
@@ -592,8 +592,6 @@ static ssize_t dlpar_show(struct class *class, struct class_attribute *attr,

static int __init pseries_dlpar_init(void)
{
- shared_topology_update();
-
pseries_hp_wq = alloc_workqueue("pseries hotplug workqueue",
WQ_UNBOUND, 1);
return sysfs_create_file(kernel_kobj, &class_attr_dlpar.attr);