2 files changed, 271 insertions, 11 deletions

diff --git a/arch/powerpc/include/asm/lppaca.h b/arch/powerpc/include/asm/lppaca.h
index 7f5e0fefebb0..380d48bacd16 100644
--- a/arch/powerpc/include/asm/lppaca.h
+++ b/arch/powerpc/include/asm/lppaca.h
@@ -62,7 +62,10 @@ struct lppaca {
         volatile u32 dyn_pir;           // Dynamic ProcIdReg value      x20-x23
         u32     dsei_data;              // DSEI data                    x24-x27
         u64     sprg3;                  // SPRG3 value                  x28-x2F
-        u8      reserved3[80];          // Reserved                     x30-x7F
+        u8      reserved3[40];          // Reserved                     x30-x57
+        volatile u8 vphn_assoc_counts[8]; // Virtual processor home node
+                                        // associativity change counters x58-x5F
+        u8      reserved4[32];          // Reserved                     x60-x7F
 
 //=============================================================================
 // CACHE_LINE_2 0x0080 - 0x00FF Contains local read-write data
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 8c0944c465f6..d644ba7e8aba 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -20,10 +20,14 @@
 #include <linux/memblock.h>
 #include <linux/of.h>
 #include <linux/pfn.h>
+#include <linux/cpuset.h>
+#include <linux/node.h>
 #include <asm/sparsemem.h>
 #include <asm/prom.h>
 #include <asm/system.h>
 #include <asm/smp.h>
+#include <asm/firmware.h>
+#include <asm/paca.h>
 
 static int numa_enabled = 1;
 
@@ -246,32 +250,41 @@ 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 of_node_to_nid_single(struct device_node *device)
+static int associativity_to_nid(const unsigned int *associativity)
 {
         int nid = -1;
-        const unsigned int *tmp;
 
         if (min_common_depth == -1)
                 goto out;
 
-        tmp = of_get_associativity(device);
-        if (!tmp)
-                goto out;
-
-        if (tmp[0] >= min_common_depth)
-                nid = tmp[min_common_depth];
+        if (associativity[0] >= min_common_depth)
+                nid = associativity[min_common_depth];
 
         /* POWER4 LPAR uses 0xffff as invalid node */
         if (nid == 0xffff || nid >= MAX_NUMNODES)
                 nid = -1;
 
-        if (nid > 0 && tmp[0] >= distance_ref_points_depth)
-                initialize_distance_lookup_table(nid, tmp);
+        if (nid > 0 && associativity[0] >= distance_ref_points_depth)
+                initialize_distance_lookup_table(nid, associativity);
 
 out:
         return nid;
 }
 
+/* Returns the nid associated with the given device tree node,
+ * or -1 if not found.
+ */
+static int of_node_to_nid_single(struct device_node *device)
+{
+        int nid = -1;
+        const unsigned int *tmp;
+
+        tmp = of_get_associativity(device);
+        if (tmp)
+                nid = associativity_to_nid(tmp);
+        return nid;
+}
+
 /* Walk the device tree upwards, looking for an associativity id */
 int of_node_to_nid(struct device_node *device)
 {
@@ -1274,3 +1287,247 @@ u64 memory_hotplug_max(void)
         return max(hot_add_drconf_memory_max(), memblock_end_of_DRAM());
 }
 #endif /* CONFIG_MEMORY_HOTPLUG */
+
+/* Vrtual Processor Home Node (VPHN) support */
+#define VPHN_NR_CHANGE_CTRS (8)
+static u8 vphn_cpu_change_counts[NR_CPUS][VPHN_NR_CHANGE_CTRS];
+static cpumask_t cpu_associativity_changes_mask;
+static int vphn_enabled;
+static void set_topology_timer(void);
+int stop_topology_update(void);
+
+/*
+ * Store the current values of the associativity change counters in the
+ * hypervisor.
+ */
+static void setup_cpu_associativity_change_counters(void)
+{
+        int cpu = 0;
+
+        for_each_possible_cpu(cpu) {
+                int i = 0;
+                u8 *counts = vphn_cpu_change_counts[cpu];
+                volatile u8 *hypervisor_counts = lppaca[cpu].vphn_assoc_counts;
+
+                for (i = 0; i < VPHN_NR_CHANGE_CTRS; 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 = 0, nr_cpus = 0;
+        cpumask_t *changes = &cpu_associativity_changes_mask;
+
+        cpumask_clear(changes);
+
+        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 < VPHN_NR_CHANGE_CTRS; i++) {
+                        if (hypervisor_counts[i] > counts[i]) {
+                                counts[i] = hypervisor_counts[i];
+                                changed = 1;
+                        }
+                }
+                if (changed) {
+                        cpumask_set_cpu(cpu, changes);
+                        nr_cpus++;
+                }
+        }
+
+        return nr_cpus;
+}
+
+/* 6 64-bit registers unpacked into 12 32-bit associativity values */
+#define VPHN_ASSOC_BUFSIZE (6*sizeof(u64)/sizeof(u32))
+
+/*
+ * Convert the associativity domain numbers returned from the hypervisor
+ * to the sequence they would appear in the ibm,associativity property.
+ */
+static int vphn_unpack_associativity(const long *packed, unsigned int *unpacked)
+{
+        int i = 0;
+        int nr_assoc_doms = 0;
+        const u16 *field = (const u16*) packed;
+
+#define VPHN_FIELD_UNUSED       (0xffff)
+#define VPHN_FIELD_MSB          (0x8000)
+#define VPHN_FIELD_MASK         (~VPHN_FIELD_MSB)
+
+        for (i = 0; i < VPHN_ASSOC_BUFSIZE; i++) {
+                if (*field == VPHN_FIELD_UNUSED) {
+                        /* All significant fields processed, and remaining
+                         * fields contain the reserved value of all 1's.
+                         * Just store them.
+                         */
+                        unpacked[i] = *((u32*)field);
+                        field += 2;
+                }
+                else if (*field & VPHN_FIELD_MSB) {
+                        /* Data is in the lower 15 bits of this field */
+                        unpacked[i] = *field & VPHN_FIELD_MASK;
+                        field++;
+                        nr_assoc_doms++;
+                }
+                else {
+                        /* Data is in the lower 15 bits of this field
+                         * concatenated with the next 16 bit field
+                         */
+                        unpacked[i] = *((u32*)field);
+                        field += 2;
+                        nr_assoc_doms++;
+                }
+        }
+
+        return nr_assoc_doms;
+}
+
+/*
+ * Retrieve the new associativity information for a virtual processor's
+ * home node.
+ */
+static long hcall_vphn(unsigned long cpu, unsigned int *associativity)
+{
+        long rc = 0;
+        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,
+                                        unsigned int *associativity)
+{
+        long rc = 0;
+
+        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();
+        }
+
+        return rc;
+}
+
+/*
+ * Update the node maps and sysfs entries for each cpu whose home node
+ * has changed.
+ */
+int arch_update_cpu_topology(void)
+{
+        int cpu = 0, nid = 0, old_nid = 0;
+        unsigned int associativity[VPHN_ASSOC_BUFSIZE] = {0};
+        struct sys_device *sysdev = NULL;
+
+        for_each_cpu_mask(cpu, cpu_associativity_changes_mask) {
+                vphn_get_associativity(cpu, associativity);
+                nid = associativity_to_nid(associativity);
+
+                if (nid < 0 || !node_online(nid))
+                        nid = first_online_node;
+
+                old_nid = numa_cpu_lookup_table[cpu];
+
+                /* Disable hotplug while we update the cpu
+                 * masks and sysfs.
+                 */
+                get_online_cpus();
+                unregister_cpu_under_node(cpu, old_nid);
+                unmap_cpu_from_node(cpu);
+                map_cpu_to_node(cpu, nid);
+                register_cpu_under_node(cpu, nid);
+                put_online_cpus();
+
+                sysdev = get_cpu_sysdev(cpu);
+                if (sysdev)
+                        kobject_uevent(&sysdev->kobj, KOBJ_CHANGE);
+        }
+
+        return 1;
+}
+
+static void topology_work_fn(struct work_struct *work)
+{
+        rebuild_sched_domains();
+}
+static DECLARE_WORK(topology_work, topology_work_fn);
+
+void topology_schedule_update(void)
+{
+        schedule_work(&topology_work);
+}
+
+static void topology_timer_fn(unsigned long ignored)
+{
+        if (!vphn_enabled)
+                return;
+        if (update_cpu_associativity_changes_mask() > 0)
+                topology_schedule_update();
+        set_topology_timer();
+}
+static struct timer_list topology_timer =
+        TIMER_INITIALIZER(topology_timer_fn, 0, 0);
+
+static void set_topology_timer(void)
+{
+        topology_timer.data = 0;
+        topology_timer.expires = jiffies + 60 * HZ;
+        add_timer(&topology_timer);
+}
+
+/*
+ * Start polling for VPHN associativity changes.
+ */
+int start_topology_update(void)
+{
+        int rc = 0;
+
+        if (firmware_has_feature(FW_FEATURE_VPHN)) {
+                vphn_enabled = 1;
+                setup_cpu_associativity_change_counters();
+                init_timer_deferrable(&topology_timer);
+                set_topology_timer();
+                rc = 1;
+        }
+
+        return rc;
+}
+__initcall(start_topology_update);
+
+/*
+ * Disable polling for VPHN associativity changes.
+ */
+int stop_topology_update(void)
+{
+        vphn_enabled = 0;
+        return del_timer_sync(&topology_timer);
+}