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numa.c

/*
 * pSeries NUMA support
 *
 * Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, 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.
 */
#include <linux/threads.h>
#include <linux/bootmem.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/module.h>
#include <linux/nodemask.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <asm/sparsemem.h>
#include <asm/lmb.h>
#include <asm/system.h>
#include <asm/smp.h>

static int numa_enabled = 1;

static int numa_debug;
#define dbg(args...) if (numa_debug) { printk(KERN_INFO args); }

int numa_cpu_lookup_table[NR_CPUS];
cpumask_t numa_cpumask_lookup_table[MAX_NUMNODES];
struct pglist_data *node_data[MAX_NUMNODES];

EXPORT_SYMBOL(numa_cpu_lookup_table);
EXPORT_SYMBOL(numa_cpumask_lookup_table);
EXPORT_SYMBOL(node_data);

static bootmem_data_t __initdata plat_node_bdata[MAX_NUMNODES];
static int min_common_depth;
static int n_mem_addr_cells, n_mem_size_cells;

static void __cpuinit map_cpu_to_node(int cpu, int node)
{
      numa_cpu_lookup_table[cpu] = node;

      dbg("adding cpu %d to node %d\n", cpu, node);

      if (!(cpu_isset(cpu, numa_cpumask_lookup_table[node])))
            cpu_set(cpu, numa_cpumask_lookup_table[node]);
}

#ifdef CONFIG_HOTPLUG_CPU
static void unmap_cpu_from_node(unsigned long cpu)
{
      int node = numa_cpu_lookup_table[cpu];

      dbg("removing cpu %lu from node %d\n", cpu, node);

      if (cpu_isset(cpu, numa_cpumask_lookup_table[node])) {
            cpu_clear(cpu, numa_cpumask_lookup_table[node]);
      } else {
            printk(KERN_ERR "WARNING: cpu %lu not found in node %d\n",
                   cpu, node);
      }
}
#endif /* CONFIG_HOTPLUG_CPU */

static struct device_node * __cpuinit find_cpu_node(unsigned int cpu)
{
      unsigned int hw_cpuid = get_hard_smp_processor_id(cpu);
      struct device_node *cpu_node = NULL;
      const unsigned int *interrupt_server, *reg;
      int len;

      while ((cpu_node = of_find_node_by_type(cpu_node, "cpu")) != NULL) {
            /* Try interrupt server first */
            interrupt_server = of_get_property(cpu_node,
                              "ibm,ppc-interrupt-server#s", &len);

            len = len / sizeof(u32);

            if (interrupt_server && (len > 0)) {
                  while (len--) {
                        if (interrupt_server[len] == hw_cpuid)
                              return cpu_node;
                  }
            } else {
                  reg = of_get_property(cpu_node, "reg", &len);
                  if (reg && (len > 0) && (reg[0] == hw_cpuid))
                        return cpu_node;
            }
      }

      return NULL;
}

/* must hold reference to node during call */
static const int *of_get_associativity(struct device_node *dev)
{
      return of_get_property(dev, "ibm,associativity", NULL);
}

/* 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)
{
      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];

      /* POWER4 LPAR uses 0xffff as invalid node */
      if (nid == 0xffff || nid >= MAX_NUMNODES)
            nid = -1;
out:
      return nid;
}

/* Walk the device tree upwards, looking for an associativity id */
int of_node_to_nid(struct device_node *device)
{
      struct device_node *tmp;
      int nid = -1;

      of_node_get(device);
      while (device) {
            nid = of_node_to_nid_single(device);
            if (nid != -1)
                  break;

              tmp = device;
            device = of_get_parent(tmp);
            of_node_put(tmp);
      }
      of_node_put(device);

      return nid;
}
EXPORT_SYMBOL_GPL(of_node_to_nid);

/*
 * In theory, the "ibm,associativity" property may contain multiple
 * associativity lists because a resource may be multiply connected
 * into the machine.  This resource then has different associativity
 * characteristics relative to its multiple connections.  We ignore
 * this for now.  We also assume that all cpu and memory sets have
 * their distances represented at a common level.  This won't be
 * true for hierarchical NUMA.
 *
 * In any case the ibm,associativity-reference-points should give
 * the correct depth for a normal NUMA system.
 *
 * - Dave Hansen <haveblue@us.ibm.com>
 */
static int __init find_min_common_depth(void)
{
      int depth;
      const unsigned int *ref_points;
      struct device_node *rtas_root;
      unsigned int len;

      rtas_root = of_find_node_by_path("/rtas");

      if (!rtas_root)
            return -1;

      /*
       * this property is 2 32-bit integers, each representing a level of
       * depth in the associativity nodes.  The first is for an SMP
       * configuration (should be all 0's) and the second is for a normal
       * NUMA configuration.
       */
      ref_points = of_get_property(rtas_root,
                  "ibm,associativity-reference-points", &len);

      if ((len >= 1) && ref_points) {
            depth = ref_points[1];
      } else {
            dbg("NUMA: ibm,associativity-reference-points not found.\n");
            depth = -1;
      }
      of_node_put(rtas_root);

      return depth;
}

static void __init get_n_mem_cells(int *n_addr_cells, int *n_size_cells)
{
      struct device_node *memory = NULL;

      memory = of_find_node_by_type(memory, "memory");
      if (!memory)
            panic("numa.c: No memory nodes found!");

      *n_addr_cells = of_n_addr_cells(memory);
      *n_size_cells = of_n_size_cells(memory);
      of_node_put(memory);
}

static unsigned long __devinit read_n_cells(int n, const unsigned int **buf)
{
      unsigned long result = 0;

      while (n--) {
            result = (result << 32) | **buf;
            (*buf)++;
      }
      return result;
}

/*
 * Figure out to which domain a cpu belongs and stick it there.
 * Return the id of the domain used.
 */
static int __cpuinit numa_setup_cpu(unsigned long lcpu)
{
      int nid = 0;
      struct device_node *cpu = find_cpu_node(lcpu);

      if (!cpu) {
            WARN_ON(1);
            goto out;
      }

      nid = of_node_to_nid_single(cpu);

      if (nid < 0 || !node_online(nid))
            nid = any_online_node(NODE_MASK_ALL);
out:
      map_cpu_to_node(lcpu, nid);

      of_node_put(cpu);

      return nid;
}

static int __cpuinit cpu_numa_callback(struct notifier_block *nfb,
                       unsigned long action,
                       void *hcpu)
{
      unsigned long lcpu = (unsigned long)hcpu;
      int ret = NOTIFY_DONE;

      switch (action) {
      case CPU_UP_PREPARE:
      case CPU_UP_PREPARE_FROZEN:
            numa_setup_cpu(lcpu);
            ret = NOTIFY_OK;
            break;
#ifdef CONFIG_HOTPLUG_CPU
      case CPU_DEAD:
      case CPU_DEAD_FROZEN:
      case CPU_UP_CANCELED:
      case CPU_UP_CANCELED_FROZEN:
            unmap_cpu_from_node(lcpu);
            break;
            ret = NOTIFY_OK;
#endif
      }
      return ret;
}

/*
 * Check and possibly modify a memory region to enforce the memory limit.
 *
 * Returns the size the region should have to enforce the memory limit.
 * This will either be the original value of size, a truncated value,
 * or zero. If the returned value of size is 0 the region should be
 * discarded as it lies wholy above the memory limit.
 */
static unsigned long __init numa_enforce_memory_limit(unsigned long start,
                                          unsigned long size)
{
      /*
       * We use lmb_end_of_DRAM() in here instead of memory_limit because
       * we've already adjusted it for the limit and it takes care of
       * having memory holes below the limit.
       */

      if (! memory_limit)
            return size;

      if (start + size <= lmb_end_of_DRAM())
            return size;

      if (start >= lmb_end_of_DRAM())
            return 0;

      return lmb_end_of_DRAM() - start;
}

/*
 * Extract NUMA information from the ibm,dynamic-reconfiguration-memory
 * node.  This assumes n_mem_{addr,size}_cells have been set.
 */
static void __init parse_drconf_memory(struct device_node *memory)
{
      const unsigned int *lm, *dm, *aa;
      unsigned int ls, ld, la;
      unsigned int n, aam, aalen;
      unsigned long lmb_size, size, start;
      int nid, default_nid = 0;
      unsigned int ai, flags;

      lm = of_get_property(memory, "ibm,lmb-size", &ls);
      dm = of_get_property(memory, "ibm,dynamic-memory", &ld);
      aa = of_get_property(memory, "ibm,associativity-lookup-arrays", &la);
      if (!lm || !dm || !aa ||
          ls < sizeof(unsigned int) || ld < sizeof(unsigned int) ||
          la < 2 * sizeof(unsigned int))
            return;

      lmb_size = read_n_cells(n_mem_size_cells, &lm);
      n = *dm++;        /* number of LMBs */
      aam = *aa++;            /* number of associativity lists */
      aalen = *aa++;          /* length of each associativity list */
      if (ld < (n * (n_mem_addr_cells + 4) + 1) * sizeof(unsigned int) ||
          la < (aam * aalen + 2) * sizeof(unsigned int))
            return;

      for (; n != 0; --n) {
            start = read_n_cells(n_mem_addr_cells, &dm);
            ai = dm[2];
            flags = dm[3];
            dm += 4;
            /* 0x80 == reserved, 0x8 = assigned to us */
            if ((flags & 0x80) || !(flags & 0x8))
                  continue;
            nid = default_nid;
            /* flags & 0x40 means associativity index is invalid */
            if (min_common_depth > 0 && min_common_depth <= aalen &&
                (flags & 0x40) == 0 && ai < aam) {
                  /* this is like of_node_to_nid_single */
                  nid = aa[ai * aalen + min_common_depth - 1];
                  if (nid == 0xffff || nid >= MAX_NUMNODES)
                        nid = default_nid;
            }
            node_set_online(nid);

            size = numa_enforce_memory_limit(start, lmb_size);
            if (!size)
                  continue;

            add_active_range(nid, start >> PAGE_SHIFT,
                         (start >> PAGE_SHIFT) + (size >> PAGE_SHIFT));
      }
}

static int __init parse_numa_properties(void)
{
      struct device_node *cpu = NULL;
      struct device_node *memory = NULL;
      int default_nid = 0;
      unsigned long i;

      if (numa_enabled == 0) {
            printk(KERN_WARNING "NUMA disabled by user\n");
            return -1;
      }

      min_common_depth = find_min_common_depth();

      if (min_common_depth < 0)
            return min_common_depth;

      dbg("NUMA associativity depth for CPU/Memory: %d\n", min_common_depth);

      /*
       * Even though we connect cpus to numa domains later in SMP
       * init, we need to know the node ids now. This is because
       * each node to be onlined must have NODE_DATA etc backing it.
       */
      for_each_present_cpu(i) {
            int nid;

            cpu = find_cpu_node(i);
            BUG_ON(!cpu);
            nid = of_node_to_nid_single(cpu);
            of_node_put(cpu);

            /*
             * Don't fall back to default_nid yet -- we will plug
             * cpus into nodes once the memory scan has discovered
             * the topology.
             */
            if (nid < 0)
                  continue;
            node_set_online(nid);
      }

      get_n_mem_cells(&n_mem_addr_cells, &n_mem_size_cells);
      memory = NULL;
      while ((memory = of_find_node_by_type(memory, "memory")) != NULL) {
            unsigned long start;
            unsigned long size;
            int nid;
            int ranges;
            const unsigned int *memcell_buf;
            unsigned int len;

            memcell_buf = of_get_property(memory,
                  "linux,usable-memory", &len);
            if (!memcell_buf || len <= 0)
                  memcell_buf = of_get_property(memory, "reg", &len);
            if (!memcell_buf || len <= 0)
                  continue;

            /* ranges in cell */
            ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
new_range:
            /* these are order-sensitive, and modify the buffer pointer */
            start = read_n_cells(n_mem_addr_cells, &memcell_buf);
            size = read_n_cells(n_mem_size_cells, &memcell_buf);

            /*
             * Assumption: either all memory nodes or none will
             * have associativity properties.  If none, then
             * everything goes to default_nid.
             */
            nid = of_node_to_nid_single(memory);
            if (nid < 0)
                  nid = default_nid;
            node_set_online(nid);

            if (!(size = numa_enforce_memory_limit(start, size))) {
                  if (--ranges)
                        goto new_range;
                  else
                        continue;
            }

            add_active_range(nid, start >> PAGE_SHIFT,
                        (start >> PAGE_SHIFT) + (size >> PAGE_SHIFT));

            if (--ranges)
                  goto new_range;
      }

      /*
       * Now do the same thing for each LMB listed in the ibm,dynamic-memory
       * property in the ibm,dynamic-reconfiguration-memory node.
       */
      memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
      if (memory)
            parse_drconf_memory(memory);

      return 0;
}

static void __init setup_nonnuma(void)
{
      unsigned long top_of_ram = lmb_end_of_DRAM();
      unsigned long total_ram = lmb_phys_mem_size();
      unsigned long start_pfn, end_pfn;
      unsigned int i;

      printk(KERN_DEBUG "Top of RAM: 0x%lx, Total RAM: 0x%lx\n",
             top_of_ram, total_ram);
      printk(KERN_DEBUG "Memory hole size: %ldMB\n",
             (top_of_ram - total_ram) >> 20);

      for (i = 0; i < lmb.memory.cnt; ++i) {
            start_pfn = lmb.memory.region[i].base >> PAGE_SHIFT;
            end_pfn = start_pfn + lmb_size_pages(&lmb.memory, i);
            add_active_range(0, start_pfn, end_pfn);
      }
      node_set_online(0);
}

void __init dump_numa_cpu_topology(void)
{
      unsigned int node;
      unsigned int cpu, count;

      if (min_common_depth == -1 || !numa_enabled)
            return;

      for_each_online_node(node) {
            printk(KERN_DEBUG "Node %d CPUs:", node);

            count = 0;
            /*
             * If we used a CPU iterator here we would miss printing
             * the holes in the cpumap.
             */
            for (cpu = 0; cpu < NR_CPUS; cpu++) {
                  if (cpu_isset(cpu, numa_cpumask_lookup_table[node])) {
                        if (count == 0)
                              printk(" %u", cpu);
                        ++count;
                  } else {
                        if (count > 1)
                              printk("-%u", cpu - 1);
                        count = 0;
                  }
            }

            if (count > 1)
                  printk("-%u", NR_CPUS - 1);
            printk("\n");
      }
}

static void __init dump_numa_memory_topology(void)
{
      unsigned int node;
      unsigned int count;

      if (min_common_depth == -1 || !numa_enabled)
            return;

      for_each_online_node(node) {
            unsigned long i;

            printk(KERN_DEBUG "Node %d Memory:", node);

            count = 0;

            for (i = 0; i < lmb_end_of_DRAM();
                 i += (1 << SECTION_SIZE_BITS)) {
                  if (early_pfn_to_nid(i >> PAGE_SHIFT) == node) {
                        if (count == 0)
                              printk(" 0x%lx", i);
                        ++count;
                  } else {
                        if (count > 0)
                              printk("-0x%lx", i);
                        count = 0;
                  }
            }

            if (count > 0)
                  printk("-0x%lx", i);
            printk("\n");
      }
}

/*
 * Allocate some memory, satisfying the lmb or bootmem allocator where
 * required. nid is the preferred node and end is the physical address of
 * the highest address in the node.
 *
 * Returns the physical address of the memory.
 */
static void __init *careful_allocation(int nid, unsigned long size,
                               unsigned long align,
                               unsigned long end_pfn)
{
      int new_nid;
      unsigned long ret = __lmb_alloc_base(size, align, end_pfn << PAGE_SHIFT);

      /* retry over all memory */
      if (!ret)
            ret = __lmb_alloc_base(size, align, lmb_end_of_DRAM());

      if (!ret)
            panic("numa.c: cannot allocate %lu bytes on node %d",
                  size, nid);

      /*
       * If the memory came from a previously allocated node, we must
       * retry with the bootmem allocator.
       */
      new_nid = early_pfn_to_nid(ret >> PAGE_SHIFT);
      if (new_nid < nid) {
            ret = (unsigned long)__alloc_bootmem_node(NODE_DATA(new_nid),
                        size, align, 0);

            if (!ret)
                  panic("numa.c: cannot allocate %lu bytes on node %d",
                        size, new_nid);

            ret = __pa(ret);

            dbg("alloc_bootmem %lx %lx\n", ret, size);
      }

      return (void *)ret;
}

static struct notifier_block __cpuinitdata ppc64_numa_nb = {
      .notifier_call = cpu_numa_callback,
      .priority = 1 /* Must run before sched domains notifier. */
};

void __init do_init_bootmem(void)
{
      int nid;
      unsigned int i;

      min_low_pfn = 0;
      max_low_pfn = lmb_end_of_DRAM() >> PAGE_SHIFT;
      max_pfn = max_low_pfn;

      if (parse_numa_properties())
            setup_nonnuma();
      else
            dump_numa_memory_topology();

      register_cpu_notifier(&ppc64_numa_nb);
      cpu_numa_callback(&ppc64_numa_nb, CPU_UP_PREPARE,
                    (void *)(unsigned long)boot_cpuid);

      for_each_online_node(nid) {
            unsigned long start_pfn, end_pfn;
            unsigned long bootmem_paddr;
            unsigned long bootmap_pages;

            get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);

            /* Allocate the node structure node local if possible */
            NODE_DATA(nid) = careful_allocation(nid,
                              sizeof(struct pglist_data),
                              SMP_CACHE_BYTES, end_pfn);
            NODE_DATA(nid) = __va(NODE_DATA(nid));
            memset(NODE_DATA(nid), 0, sizeof(struct pglist_data));

            dbg("node %d\n", nid);
            dbg("NODE_DATA() = %p\n", NODE_DATA(nid));

            NODE_DATA(nid)->bdata = &plat_node_bdata[nid];
            NODE_DATA(nid)->node_start_pfn = start_pfn;
            NODE_DATA(nid)->node_spanned_pages = end_pfn - start_pfn;

            if (NODE_DATA(nid)->node_spanned_pages == 0)
                  continue;

            dbg("start_paddr = %lx\n", start_pfn << PAGE_SHIFT);
            dbg("end_paddr = %lx\n", end_pfn << PAGE_SHIFT);

            bootmap_pages = bootmem_bootmap_pages(end_pfn - start_pfn);
            bootmem_paddr = (unsigned long)careful_allocation(nid,
                              bootmap_pages << PAGE_SHIFT,
                              PAGE_SIZE, end_pfn);
            memset(__va(bootmem_paddr), 0, bootmap_pages << PAGE_SHIFT);

            dbg("bootmap_paddr = %lx\n", bootmem_paddr);

            init_bootmem_node(NODE_DATA(nid), bootmem_paddr >> PAGE_SHIFT,
                          start_pfn, end_pfn);

            free_bootmem_with_active_regions(nid, end_pfn);

            /* Mark reserved regions on this node */
            for (i = 0; i < lmb.reserved.cnt; i++) {
                  unsigned long physbase = lmb.reserved.region[i].base;
                  unsigned long size = lmb.reserved.region[i].size;
                  unsigned long start_paddr = start_pfn << PAGE_SHIFT;
                  unsigned long end_paddr = end_pfn << PAGE_SHIFT;

                  if (early_pfn_to_nid(physbase >> PAGE_SHIFT) != nid &&
                      early_pfn_to_nid((physbase+size-1) >> PAGE_SHIFT) != nid)
                        continue;

                  if (physbase < end_paddr &&
                      (physbase+size) > start_paddr) {
                        /* overlaps */
                        if (physbase < start_paddr) {
                              size -= start_paddr - physbase;
                              physbase = start_paddr;
                        }

                        if (size > end_paddr - physbase)
                              size = end_paddr - physbase;

                        dbg("reserve_bootmem %lx %lx\n", physbase,
                            size);
                        reserve_bootmem_node(NODE_DATA(nid), physbase,
                                         size);
                  }
            }

            sparse_memory_present_with_active_regions(nid);
      }
}

void __init paging_init(void)
{
      unsigned long max_zone_pfns[MAX_NR_ZONES];
      memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
      max_zone_pfns[ZONE_DMA] = lmb_end_of_DRAM() >> PAGE_SHIFT;
      free_area_init_nodes(max_zone_pfns);
}

static int __init early_numa(char *p)
{
      if (!p)
            return 0;

      if (strstr(p, "off"))
            numa_enabled = 0;

      if (strstr(p, "debug"))
            numa_debug = 1;

      return 0;
}
early_param("numa", early_numa);

#ifdef CONFIG_MEMORY_HOTPLUG
/*
 * Find the node associated with a hot added memory section.  Section
 * corresponds to a SPARSEMEM section, not an LMB.  It is assumed that
 * sections are fully contained within a single LMB.
 */
int hot_add_scn_to_nid(unsigned long scn_addr)
{
      struct device_node *memory = NULL;
      nodemask_t nodes;
      int default_nid = any_online_node(NODE_MASK_ALL);
      int nid;

      if (!numa_enabled || (min_common_depth < 0))
            return default_nid;

      while ((memory = of_find_node_by_type(memory, "memory")) != NULL) {
            unsigned long start, size;
            int ranges;
            const unsigned int *memcell_buf;
            unsigned int len;

            memcell_buf = of_get_property(memory, "reg", &len);
            if (!memcell_buf || len <= 0)
                  continue;

            /* ranges in cell */
            ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
ha_new_range:
            start = read_n_cells(n_mem_addr_cells, &memcell_buf);
            size = read_n_cells(n_mem_size_cells, &memcell_buf);
            nid = of_node_to_nid_single(memory);

            /* Domains not present at boot default to 0 */
            if (nid < 0 || !node_online(nid))
                  nid = default_nid;

            if ((scn_addr >= start) && (scn_addr < (start + size))) {
                  of_node_put(memory);
                  goto got_nid;
            }

            if (--ranges)           /* process all ranges in cell */
                  goto ha_new_range;
      }
      BUG();      /* section address should be found above */
      return 0;

      /* Temporary code to ensure that returned node is not empty */
got_nid:
      nodes_setall(nodes);
      while (NODE_DATA(nid)->node_spanned_pages == 0) {
            node_clear(nid, nodes);
            nid = any_online_node(nodes);
      }
      return nid;
}
#endif /* CONFIG_MEMORY_HOTPLUG */

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