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init.c

/*
 *  linux/arch/parisc/mm/init.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *  Copyright 1999 SuSE GmbH
 *    changed by Philipp Rumpf
 *  Copyright 1999 Philipp Rumpf (prumpf@tux.org)
 *  Copyright 2004 Randolph Chung (tausq@debian.org)
 *  Copyright 2006-2007 Helge Deller (deller@gmx.de)
 *
 */


#include <linux/module.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/pci.h>        /* for hppa_dma_ops and pcxl_dma_ops */
#include <linux/initrd.h>
#include <linux/swap.h>
#include <linux/unistd.h>
#include <linux/nodemask.h>   /* for node_online_map */
#include <linux/pagemap.h>    /* for release_pages and page_cache_release */

#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/tlb.h>
#include <asm/pdc_chassis.h>
#include <asm/mmzone.h>
#include <asm/sections.h>

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

extern int  data_start;

#ifdef CONFIG_DISCONTIGMEM
struct node_map_data node_data[MAX_NUMNODES] __read_mostly;
unsigned char pfnnid_map[PFNNID_MAP_MAX] __read_mostly;
#endif

static struct resource data_resource = {
      .name = "Kernel data",
      .flags      = IORESOURCE_BUSY | IORESOURCE_MEM,
};

static struct resource code_resource = {
      .name = "Kernel code",
      .flags      = IORESOURCE_BUSY | IORESOURCE_MEM,
};

static struct resource pdcdata_resource = {
      .name = "PDC data (Page Zero)",
      .start      = 0,
      .end  = 0x9ff,
      .flags      = IORESOURCE_BUSY | IORESOURCE_MEM,
};

static struct resource sysram_resources[MAX_PHYSMEM_RANGES] __read_mostly;

/* The following array is initialized from the firmware specific
 * information retrieved in kernel/inventory.c.
 */

physmem_range_t pmem_ranges[MAX_PHYSMEM_RANGES] __read_mostly;
int npmem_ranges __read_mostly;

#ifdef CONFIG_64BIT
#define MAX_MEM         (~0UL)
#else /* !CONFIG_64BIT */
#define MAX_MEM         (3584U*1024U*1024U)
#endif /* !CONFIG_64BIT */

static unsigned long mem_limit __read_mostly = MAX_MEM;

static void __init mem_limit_func(void)
{
      char *cp, *end;
      unsigned long limit;

      /* We need this before __setup() functions are called */

      limit = MAX_MEM;
      for (cp = boot_command_line; *cp; ) {
            if (memcmp(cp, "mem=", 4) == 0) {
                  cp += 4;
                  limit = memparse(cp, &end);
                  if (end != cp)
                        break;
                  cp = end;
            } else {
                  while (*cp != ' ' && *cp)
                        ++cp;
                  while (*cp == ' ')
                        ++cp;
            }
      }

      if (limit < mem_limit)
            mem_limit = limit;
}

#define MAX_GAP (0x40000000UL >> PAGE_SHIFT)

static void __init setup_bootmem(void)
{
      unsigned long bootmap_size;
      unsigned long mem_max;
      unsigned long bootmap_pages;
      unsigned long bootmap_start_pfn;
      unsigned long bootmap_pfn;
#ifndef CONFIG_DISCONTIGMEM
      physmem_range_t pmem_holes[MAX_PHYSMEM_RANGES - 1];
      int npmem_holes;
#endif
      int i, sysram_resource_count;

      disable_sr_hashing(); /* Turn off space register hashing */

      /*
       * Sort the ranges. Since the number of ranges is typically
       * small, and performance is not an issue here, just do
       * a simple insertion sort.
       */

      for (i = 1; i < npmem_ranges; i++) {
            int j;

            for (j = i; j > 0; j--) {
                  unsigned long tmp;

                  if (pmem_ranges[j-1].start_pfn <
                      pmem_ranges[j].start_pfn) {

                        break;
                  }
                  tmp = pmem_ranges[j-1].start_pfn;
                  pmem_ranges[j-1].start_pfn = pmem_ranges[j].start_pfn;
                  pmem_ranges[j].start_pfn = tmp;
                  tmp = pmem_ranges[j-1].pages;
                  pmem_ranges[j-1].pages = pmem_ranges[j].pages;
                  pmem_ranges[j].pages = tmp;
            }
      }

#ifndef CONFIG_DISCONTIGMEM
      /*
       * Throw out ranges that are too far apart (controlled by
       * MAX_GAP).
       */

      for (i = 1; i < npmem_ranges; i++) {
            if (pmem_ranges[i].start_pfn -
                  (pmem_ranges[i-1].start_pfn +
                   pmem_ranges[i-1].pages) > MAX_GAP) {
                  npmem_ranges = i;
                  printk("Large gap in memory detected (%ld pages). "
                         "Consider turning on CONFIG_DISCONTIGMEM\n",
                         pmem_ranges[i].start_pfn -
                         (pmem_ranges[i-1].start_pfn +
                          pmem_ranges[i-1].pages));
                  break;
            }
      }
#endif

      if (npmem_ranges > 1) {

            /* Print the memory ranges */

            printk(KERN_INFO "Memory Ranges:\n");

            for (i = 0; i < npmem_ranges; i++) {
                  unsigned long start;
                  unsigned long size;

                  size = (pmem_ranges[i].pages << PAGE_SHIFT);
                  start = (pmem_ranges[i].start_pfn << PAGE_SHIFT);
                  printk(KERN_INFO "%2d) Start 0x%016lx End 0x%016lx Size %6ld MB\n",
                        i,start, start + (size - 1), size >> 20);
            }
      }

      sysram_resource_count = npmem_ranges;
      for (i = 0; i < sysram_resource_count; i++) {
            struct resource *res = &sysram_resources[i];
            res->name = "System RAM";
            res->start = pmem_ranges[i].start_pfn << PAGE_SHIFT;
            res->end = res->start + (pmem_ranges[i].pages << PAGE_SHIFT)-1;
            res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
            request_resource(&iomem_resource, res);
      }

      /*
       * For 32 bit kernels we limit the amount of memory we can
       * support, in order to preserve enough kernel address space
       * for other purposes. For 64 bit kernels we don't normally
       * limit the memory, but this mechanism can be used to
       * artificially limit the amount of memory (and it is written
       * to work with multiple memory ranges).
       */

      mem_limit_func();       /* check for "mem=" argument */

      mem_max = 0;
      num_physpages = 0;
      for (i = 0; i < npmem_ranges; i++) {
            unsigned long rsize;

            rsize = pmem_ranges[i].pages << PAGE_SHIFT;
            if ((mem_max + rsize) > mem_limit) {
                  printk(KERN_WARNING "Memory truncated to %ld MB\n", mem_limit >> 20);
                  if (mem_max == mem_limit)
                        npmem_ranges = i;
                  else {
                        pmem_ranges[i].pages =   (mem_limit >> PAGE_SHIFT)
                                           - (mem_max >> PAGE_SHIFT);
                        npmem_ranges = i + 1;
                        mem_max = mem_limit;
                  }
              num_physpages += pmem_ranges[i].pages;
                  break;
            }
          num_physpages += pmem_ranges[i].pages;
            mem_max += rsize;
      }

      printk(KERN_INFO "Total Memory: %ld MB\n",mem_max >> 20);

#ifndef CONFIG_DISCONTIGMEM
      /* Merge the ranges, keeping track of the holes */

      {
            unsigned long end_pfn;
            unsigned long hole_pages;

            npmem_holes = 0;
            end_pfn = pmem_ranges[0].start_pfn + pmem_ranges[0].pages;
            for (i = 1; i < npmem_ranges; i++) {

                  hole_pages = pmem_ranges[i].start_pfn - end_pfn;
                  if (hole_pages) {
                        pmem_holes[npmem_holes].start_pfn = end_pfn;
                        pmem_holes[npmem_holes++].pages = hole_pages;
                        end_pfn += hole_pages;
                  }
                  end_pfn += pmem_ranges[i].pages;
            }

            pmem_ranges[0].pages = end_pfn - pmem_ranges[0].start_pfn;
            npmem_ranges = 1;
      }
#endif

      bootmap_pages = 0;
      for (i = 0; i < npmem_ranges; i++)
            bootmap_pages += bootmem_bootmap_pages(pmem_ranges[i].pages);

      bootmap_start_pfn = PAGE_ALIGN(__pa((unsigned long) &_end)) >> PAGE_SHIFT;

#ifdef CONFIG_DISCONTIGMEM
      for (i = 0; i < MAX_PHYSMEM_RANGES; i++) {
            memset(NODE_DATA(i), 0, sizeof(pg_data_t));
            NODE_DATA(i)->bdata = &bootmem_node_data[i];
      }
      memset(pfnnid_map, 0xff, sizeof(pfnnid_map));

      for (i = 0; i < npmem_ranges; i++)
            node_set_online(i);
#endif

      /*
       * Initialize and free the full range of memory in each range.
       * Note that the only writing these routines do are to the bootmap,
       * and we've made sure to locate the bootmap properly so that they
       * won't be writing over anything important.
       */

      bootmap_pfn = bootmap_start_pfn;
      max_pfn = 0;
      for (i = 0; i < npmem_ranges; i++) {
            unsigned long start_pfn;
            unsigned long npages;

            start_pfn = pmem_ranges[i].start_pfn;
            npages = pmem_ranges[i].pages;

            bootmap_size = init_bootmem_node(NODE_DATA(i),
                                    bootmap_pfn,
                                    start_pfn,
                                    (start_pfn + npages) );
            free_bootmem_node(NODE_DATA(i),
                          (start_pfn << PAGE_SHIFT),
                          (npages << PAGE_SHIFT) );
            bootmap_pfn += (bootmap_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
            if ((start_pfn + npages) > max_pfn)
                  max_pfn = start_pfn + npages;
      }

      /* IOMMU is always used to access "high mem" on those boxes
       * that can support enough mem that a PCI device couldn't
       * directly DMA to any physical addresses.
       * ISA DMA support will need to revisit this.
       */
      max_low_pfn = max_pfn;

      if ((bootmap_pfn - bootmap_start_pfn) != bootmap_pages) {
            printk(KERN_WARNING "WARNING! bootmap sizing is messed up!\n");
            BUG();
      }

      /* reserve PAGE0 pdc memory, kernel text/data/bss & bootmap */

#define PDC_CONSOLE_IO_IODC_SIZE 32768

      reserve_bootmem_node(NODE_DATA(0), 0UL,
                  (unsigned long)(PAGE0->mem_free +
                        PDC_CONSOLE_IO_IODC_SIZE), BOOTMEM_DEFAULT);
      reserve_bootmem_node(NODE_DATA(0), __pa((unsigned long)_text),
                  (unsigned long)(_end - _text), BOOTMEM_DEFAULT);
      reserve_bootmem_node(NODE_DATA(0), (bootmap_start_pfn << PAGE_SHIFT),
                  ((bootmap_pfn - bootmap_start_pfn) << PAGE_SHIFT),
                  BOOTMEM_DEFAULT);

#ifndef CONFIG_DISCONTIGMEM

      /* reserve the holes */

      for (i = 0; i < npmem_holes; i++) {
            reserve_bootmem_node(NODE_DATA(0),
                        (pmem_holes[i].start_pfn << PAGE_SHIFT),
                        (pmem_holes[i].pages << PAGE_SHIFT),
                        BOOTMEM_DEFAULT);
      }
#endif

#ifdef CONFIG_BLK_DEV_INITRD
      if (initrd_start) {
            printk(KERN_INFO "initrd: %08lx-%08lx\n", initrd_start, initrd_end);
            if (__pa(initrd_start) < mem_max) {
                  unsigned long initrd_reserve;

                  if (__pa(initrd_end) > mem_max) {
                        initrd_reserve = mem_max - __pa(initrd_start);
                  } else {
                        initrd_reserve = initrd_end - initrd_start;
                  }
                  initrd_below_start_ok = 1;
                  printk(KERN_INFO "initrd: reserving %08lx-%08lx (mem_max %08lx)\n", __pa(initrd_start), __pa(initrd_start) + initrd_reserve, mem_max);

                  reserve_bootmem_node(NODE_DATA(0), __pa(initrd_start),
                              initrd_reserve, BOOTMEM_DEFAULT);
            }
      }
#endif

      data_resource.start =  virt_to_phys(&data_start);
      data_resource.end = virt_to_phys(_end) - 1;
      code_resource.start = virt_to_phys(_text);
      code_resource.end = virt_to_phys(&data_start)-1;

      /* We don't know which region the kernel will be in, so try
       * all of them.
       */
      for (i = 0; i < sysram_resource_count; i++) {
            struct resource *res = &sysram_resources[i];
            request_resource(res, &code_resource);
            request_resource(res, &data_resource);
      }
      request_resource(&sysram_resources[0], &pdcdata_resource);
}

void free_initmem(void)
{
      unsigned long addr, init_begin, init_end;

      printk(KERN_INFO "Freeing unused kernel memory: ");

#ifdef CONFIG_DEBUG_KERNEL
      /* Attempt to catch anyone trying to execute code here
       * by filling the page with BRK insns.
       * 
       * If we disable interrupts for all CPUs, then IPI stops working.
       * Kinda breaks the global cache flushing.
       */
      local_irq_disable();

      memset(__init_begin, 0x00,
            (unsigned long)__init_end - (unsigned long)__init_begin);

      flush_data_cache();
      asm volatile("sync" : : );
      flush_icache_range((unsigned long)__init_begin, (unsigned long)__init_end);
      asm volatile("sync" : : );

      local_irq_enable();
#endif
      
      /* align __init_begin and __init_end to page size,
         ignoring linker script where we might have tried to save RAM */
      init_begin = PAGE_ALIGN((unsigned long)(__init_begin));
      init_end   = PAGE_ALIGN((unsigned long)(__init_end));
      for (addr = init_begin; addr < init_end; addr += PAGE_SIZE) {
            ClearPageReserved(virt_to_page(addr));
            init_page_count(virt_to_page(addr));
            free_page(addr);
            num_physpages++;
            totalram_pages++;
      }

      /* set up a new led state on systems shipped LED State panel */
      pdc_chassis_send_status(PDC_CHASSIS_DIRECT_BCOMPLETE);
      
      printk("%luk freed\n", (init_end - init_begin) >> 10);
}


#ifdef CONFIG_DEBUG_RODATA
void mark_rodata_ro(void)
{
      /* rodata memory was already mapped with KERNEL_RO access rights by
           pagetable_init() and map_pages(). No need to do additional stuff here */
      printk (KERN_INFO "Write protecting the kernel read-only data: %luk\n",
            (unsigned long)(__end_rodata - __start_rodata) >> 10);
}
#endif


/*
 * Just an arbitrary offset to serve as a "hole" between mapping areas
 * (between top of physical memory and a potential pcxl dma mapping
 * area, and below the vmalloc mapping area).
 *
 * The current 32K value just means that there will be a 32K "hole"
 * between mapping areas. That means that  any out-of-bounds memory
 * accesses will hopefully be caught. The vmalloc() routines leaves
 * a hole of 4kB between each vmalloced area for the same reason.
 */

 /* Leave room for gateway page expansion */
#if KERNEL_MAP_START < GATEWAY_PAGE_SIZE
#error KERNEL_MAP_START is in gateway reserved region
#endif
#define MAP_START (KERNEL_MAP_START)

#define VM_MAP_OFFSET  (32*1024)
#define SET_MAP_OFFSET(x) ((void *)(((unsigned long)(x) + VM_MAP_OFFSET) \
                             & ~(VM_MAP_OFFSET-1)))

void *vmalloc_start __read_mostly;
EXPORT_SYMBOL(vmalloc_start);

#ifdef CONFIG_PA11
unsigned long pcxl_dma_start __read_mostly;
#endif

void __init mem_init(void)
{
      int codesize, reservedpages, datasize, initsize;

      high_memory = __va((max_pfn << PAGE_SHIFT));

#ifndef CONFIG_DISCONTIGMEM
      max_mapnr = page_to_pfn(virt_to_page(high_memory - 1)) + 1;
      totalram_pages += free_all_bootmem();
#else
      {
            int i;

            for (i = 0; i < npmem_ranges; i++)
                  totalram_pages += free_all_bootmem_node(NODE_DATA(i));
      }
#endif

      codesize = (unsigned long)_etext - (unsigned long)_text;
      datasize = (unsigned long)_edata - (unsigned long)_etext;
      initsize = (unsigned long)__init_end - (unsigned long)__init_begin;

      reservedpages = 0;
{
      unsigned long pfn;
#ifdef CONFIG_DISCONTIGMEM
      int i;

      for (i = 0; i < npmem_ranges; i++) {
            for (pfn = node_start_pfn(i); pfn < node_end_pfn(i); pfn++) {
                  if (PageReserved(pfn_to_page(pfn)))
                        reservedpages++;
            }
      }
#else /* !CONFIG_DISCONTIGMEM */
      for (pfn = 0; pfn < max_pfn; pfn++) {
            /*
             * Only count reserved RAM pages
             */
            if (PageReserved(pfn_to_page(pfn)))
                  reservedpages++;
      }
#endif
}

#ifdef CONFIG_PA11
      if (hppa_dma_ops == &pcxl_dma_ops) {
            pcxl_dma_start = (unsigned long)SET_MAP_OFFSET(MAP_START);
            vmalloc_start = SET_MAP_OFFSET(pcxl_dma_start + PCXL_DMA_MAP_SIZE);
      } else {
            pcxl_dma_start = 0;
            vmalloc_start = SET_MAP_OFFSET(MAP_START);
      }
#else
      vmalloc_start = SET_MAP_OFFSET(MAP_START);
#endif

      printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init)\n",
            (unsigned long)nr_free_pages() << (PAGE_SHIFT-10),
            num_physpages << (PAGE_SHIFT-10),
            codesize >> 10,
            reservedpages << (PAGE_SHIFT-10),
            datasize >> 10,
            initsize >> 10
      );

#ifdef CONFIG_DEBUG_KERNEL /* double-sanity-check paranoia */
      printk("virtual kernel memory layout:\n"
             "    vmalloc : 0x%p - 0x%p   (%4ld MB)\n"
             "    memory  : 0x%p - 0x%p   (%4ld MB)\n"
             "      .init : 0x%p - 0x%p   (%4ld kB)\n"
             "      .data : 0x%p - 0x%p   (%4ld kB)\n"
             "      .text : 0x%p - 0x%p   (%4ld kB)\n",

             (void*)VMALLOC_START, (void*)VMALLOC_END,
             (VMALLOC_END - VMALLOC_START) >> 20,

             __va(0), high_memory,
             ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,

             __init_begin, __init_end,
             ((unsigned long)__init_end - (unsigned long)__init_begin) >> 10,

             _etext, _edata,
             ((unsigned long)_edata - (unsigned long)_etext) >> 10,

             _text, _etext,
             ((unsigned long)_etext - (unsigned long)_text) >> 10);
#endif
}

unsigned long *empty_zero_page __read_mostly;
EXPORT_SYMBOL(empty_zero_page);

void show_mem(void)
{
      int i,free = 0,total = 0,reserved = 0;
      int shared = 0, cached = 0;

      printk(KERN_INFO "Mem-info:\n");
      show_free_areas();
#ifndef CONFIG_DISCONTIGMEM
      i = max_mapnr;
      while (i-- > 0) {
            total++;
            if (PageReserved(mem_map+i))
                  reserved++;
            else if (PageSwapCache(mem_map+i))
                  cached++;
            else if (!page_count(&mem_map[i]))
                  free++;
            else
                  shared += page_count(&mem_map[i]) - 1;
      }
#else
      for (i = 0; i < npmem_ranges; i++) {
            int j;

            for (j = node_start_pfn(i); j < node_end_pfn(i); j++) {
                  struct page *p;
                  unsigned long flags;

                  pgdat_resize_lock(NODE_DATA(i), &flags);
                  p = nid_page_nr(i, j) - node_start_pfn(i);

                  total++;
                  if (PageReserved(p))
                        reserved++;
                  else if (PageSwapCache(p))
                        cached++;
                  else if (!page_count(p))
                        free++;
                  else
                        shared += page_count(p) - 1;
                  pgdat_resize_unlock(NODE_DATA(i), &flags);
            }
      }
#endif
      printk(KERN_INFO "%d pages of RAM\n", total);
      printk(KERN_INFO "%d reserved pages\n", reserved);
      printk(KERN_INFO "%d pages shared\n", shared);
      printk(KERN_INFO "%d pages swap cached\n", cached);


#ifdef CONFIG_DISCONTIGMEM
      {
            struct zonelist *zl;
            int i, j;

            for (i = 0; i < npmem_ranges; i++) {
                  zl = node_zonelist(i, 0);
                  for (j = 0; j < MAX_NR_ZONES; j++) {
                        struct zoneref *z;
                        struct zone *zone;

                        printk("Zone list for zone %d on node %d: ", j, i);
                        for_each_zone_zonelist(zone, z, zl, j)
                              printk("[%d/%s] ", zone_to_nid(zone),
                                                zone->name);
                        printk("\n");
                  }
            }
      }
#endif
}


static void __init map_pages(unsigned long start_vaddr, unsigned long start_paddr, unsigned long size, pgprot_t pgprot)
{
      pgd_t *pg_dir;
      pmd_t *pmd;
      pte_t *pg_table;
      unsigned long end_paddr;
      unsigned long start_pmd;
      unsigned long start_pte;
      unsigned long tmp1;
      unsigned long tmp2;
      unsigned long address;
      unsigned long ro_start;
      unsigned long ro_end;
      unsigned long fv_addr;
      unsigned long gw_addr;
      extern const unsigned long fault_vector_20;
      extern void * const linux_gateway_page;

      ro_start = __pa((unsigned long)_text);
      ro_end   = __pa((unsigned long)&data_start);
      fv_addr  = __pa((unsigned long)&fault_vector_20) & PAGE_MASK;
      gw_addr  = __pa((unsigned long)&linux_gateway_page) & PAGE_MASK;

      end_paddr = start_paddr + size;

      pg_dir = pgd_offset_k(start_vaddr);

#if PTRS_PER_PMD == 1
      start_pmd = 0;
#else
      start_pmd = ((start_vaddr >> PMD_SHIFT) & (PTRS_PER_PMD - 1));
#endif
      start_pte = ((start_vaddr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1));

      address = start_paddr;
      while (address < end_paddr) {
#if PTRS_PER_PMD == 1
            pmd = (pmd_t *)__pa(pg_dir);
#else
            pmd = (pmd_t *)pgd_address(*pg_dir);

            /*
             * pmd is physical at this point
             */

            if (!pmd) {
                  pmd = (pmd_t *) alloc_bootmem_low_pages_node(NODE_DATA(0),PAGE_SIZE << PMD_ORDER);
                  pmd = (pmd_t *) __pa(pmd);
            }

            pgd_populate(NULL, pg_dir, __va(pmd));
#endif
            pg_dir++;

            /* now change pmd to kernel virtual addresses */

            pmd = (pmd_t *)__va(pmd) + start_pmd;
            for (tmp1 = start_pmd; tmp1 < PTRS_PER_PMD; tmp1++,pmd++) {

                  /*
                   * pg_table is physical at this point
                   */

                  pg_table = (pte_t *)pmd_address(*pmd);
                  if (!pg_table) {
                        pg_table = (pte_t *)
                              alloc_bootmem_low_pages_node(NODE_DATA(0),PAGE_SIZE);
                        pg_table = (pte_t *) __pa(pg_table);
                  }

                  pmd_populate_kernel(NULL, pmd, __va(pg_table));

                  /* now change pg_table to kernel virtual addresses */

                  pg_table = (pte_t *) __va(pg_table) + start_pte;
                  for (tmp2 = start_pte; tmp2 < PTRS_PER_PTE; tmp2++,pg_table++) {
                        pte_t pte;

                        /*
                         * Map the fault vector writable so we can
                         * write the HPMC checksum.
                         */
#if defined(CONFIG_PARISC_PAGE_SIZE_4KB)
                        if (address >= ro_start && address < ro_end
                                          && address != fv_addr
                                          && address != gw_addr)
                            pte = __mk_pte(address, PAGE_KERNEL_RO);
                        else
#endif
                            pte = __mk_pte(address, pgprot);

                        if (address >= end_paddr)
                              pte_val(pte) = 0;

                        set_pte(pg_table, pte);

                        address += PAGE_SIZE;
                  }
                  start_pte = 0;

                  if (address >= end_paddr)
                      break;
            }
            start_pmd = 0;
      }
}

/*
 * pagetable_init() sets up the page tables
 *
 * Note that gateway_init() places the Linux gateway page at page 0.
 * Since gateway pages cannot be dereferenced this has the desirable
 * side effect of trapping those pesky NULL-reference errors in the
 * kernel.
 */
static void __init pagetable_init(void)
{
      int range;

      /* Map each physical memory range to its kernel vaddr */

      for (range = 0; range < npmem_ranges; range++) {
            unsigned long start_paddr;
            unsigned long end_paddr;
            unsigned long size;

            start_paddr = pmem_ranges[range].start_pfn << PAGE_SHIFT;
            end_paddr = start_paddr + (pmem_ranges[range].pages << PAGE_SHIFT);
            size = pmem_ranges[range].pages << PAGE_SHIFT;

            map_pages((unsigned long)__va(start_paddr), start_paddr,
                  size, PAGE_KERNEL);
      }

#ifdef CONFIG_BLK_DEV_INITRD
      if (initrd_end && initrd_end > mem_limit) {
            printk(KERN_INFO "initrd: mapping %08lx-%08lx\n", initrd_start, initrd_end);
            map_pages(initrd_start, __pa(initrd_start),
                  initrd_end - initrd_start, PAGE_KERNEL);
      }
#endif

      empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
      memset(empty_zero_page, 0, PAGE_SIZE);
}

static void __init gateway_init(void)
{
      unsigned long linux_gateway_page_addr;
      /* FIXME: This is 'const' in order to trick the compiler
         into not treating it as DP-relative data. */
      extern void * const linux_gateway_page;

      linux_gateway_page_addr = LINUX_GATEWAY_ADDR & PAGE_MASK;

      /*
       * Setup Linux Gateway page.
       *
       * The Linux gateway page will reside in kernel space (on virtual
       * page 0), so it doesn't need to be aliased into user space.
       */

      map_pages(linux_gateway_page_addr, __pa(&linux_gateway_page),
            PAGE_SIZE, PAGE_GATEWAY);
}

#ifdef CONFIG_HPUX
void
map_hpux_gateway_page(struct task_struct *tsk, struct mm_struct *mm)
{
      pgd_t *pg_dir;
      pmd_t *pmd;
      pte_t *pg_table;
      unsigned long start_pmd;
      unsigned long start_pte;
      unsigned long address;
      unsigned long hpux_gw_page_addr;
      /* FIXME: This is 'const' in order to trick the compiler
         into not treating it as DP-relative data. */
      extern void * const hpux_gateway_page;

      hpux_gw_page_addr = HPUX_GATEWAY_ADDR & PAGE_MASK;

      /*
       * Setup HP-UX Gateway page.
       *
       * The HP-UX gateway page resides in the user address space,
       * so it needs to be aliased into each process.
       */

      pg_dir = pgd_offset(mm,hpux_gw_page_addr);

#if PTRS_PER_PMD == 1
      start_pmd = 0;
#else
      start_pmd = ((hpux_gw_page_addr >> PMD_SHIFT) & (PTRS_PER_PMD - 1));
#endif
      start_pte = ((hpux_gw_page_addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1));

      address = __pa(&hpux_gateway_page);
#if PTRS_PER_PMD == 1
      pmd = (pmd_t *)__pa(pg_dir);
#else
      pmd = (pmd_t *) pgd_address(*pg_dir);

      /*
       * pmd is physical at this point
       */

      if (!pmd) {
            pmd = (pmd_t *) get_zeroed_page(GFP_KERNEL);
            pmd = (pmd_t *) __pa(pmd);
      }

      __pgd_val_set(*pg_dir, PxD_FLAG_PRESENT | PxD_FLAG_VALID | (unsigned long) pmd);
#endif
      /* now change pmd to kernel virtual addresses */

      pmd = (pmd_t *)__va(pmd) + start_pmd;

      /*
       * pg_table is physical at this point
       */

      pg_table = (pte_t *) pmd_address(*pmd);
      if (!pg_table)
            pg_table = (pte_t *) __pa(get_zeroed_page(GFP_KERNEL));

      __pmd_val_set(*pmd, PxD_FLAG_PRESENT | PxD_FLAG_VALID | (unsigned long) pg_table);

      /* now change pg_table to kernel virtual addresses */

      pg_table = (pte_t *) __va(pg_table) + start_pte;
      set_pte(pg_table, __mk_pte(address, PAGE_GATEWAY));
}
EXPORT_SYMBOL(map_hpux_gateway_page);
#endif

void __init paging_init(void)
{
      int i;

      setup_bootmem();
      pagetable_init();
      gateway_init();
      flush_cache_all_local(); /* start with known state */
      flush_tlb_all_local(NULL);

      for (i = 0; i < npmem_ranges; i++) {
            unsigned long zones_size[MAX_NR_ZONES] = { 0, };

            zones_size[ZONE_NORMAL] = pmem_ranges[i].pages;

#ifdef CONFIG_DISCONTIGMEM
            /* Need to initialize the pfnnid_map before we can initialize
               the zone */
            {
                int j;
                for (j = (pmem_ranges[i].start_pfn >> PFNNID_SHIFT);
                   j <= ((pmem_ranges[i].start_pfn + pmem_ranges[i].pages) >> PFNNID_SHIFT);
                   j++) {
                  pfnnid_map[j] = i;
                }
            }
#endif

            free_area_init_node(i, zones_size,
                        pmem_ranges[i].start_pfn, NULL);
      }
}

#ifdef CONFIG_PA20

/*
 * Currently, all PA20 chips have 18 bit protection IDs, which is the
 * limiting factor (space ids are 32 bits).
 */

#define NR_SPACE_IDS 262144

#else

/*
 * Currently we have a one-to-one relationship between space IDs and
 * protection IDs. Older parisc chips (PCXS, PCXT, PCXL, PCXL2) only
 * support 15 bit protection IDs, so that is the limiting factor.
 * PCXT' has 18 bit protection IDs, but only 16 bit spaceids, so it's
 * probably not worth the effort for a special case here.
 */

#define NR_SPACE_IDS 32768

#endif  /* !CONFIG_PA20 */

#define RECYCLE_THRESHOLD (NR_SPACE_IDS / 2)
#define SID_ARRAY_SIZE  (NR_SPACE_IDS / (8 * sizeof(long)))

static unsigned long space_id[SID_ARRAY_SIZE] = { 1 }; /* disallow space 0 */
static unsigned long dirty_space_id[SID_ARRAY_SIZE];
static unsigned long space_id_index;
static unsigned long free_space_ids = NR_SPACE_IDS - 1;
static unsigned long dirty_space_ids = 0;

static DEFINE_SPINLOCK(sid_lock);

unsigned long alloc_sid(void)
{
      unsigned long index;

      spin_lock(&sid_lock);

      if (free_space_ids == 0) {
            if (dirty_space_ids != 0) {
                  spin_unlock(&sid_lock);
                  flush_tlb_all(); /* flush_tlb_all() calls recycle_sids() */
                  spin_lock(&sid_lock);
            }
            BUG_ON(free_space_ids == 0);
      }

      free_space_ids--;

      index = find_next_zero_bit(space_id, NR_SPACE_IDS, space_id_index);
      space_id[index >> SHIFT_PER_LONG] |= (1L << (index & (BITS_PER_LONG - 1)));
      space_id_index = index;

      spin_unlock(&sid_lock);

      return index << SPACEID_SHIFT;
}

void free_sid(unsigned long spaceid)
{
      unsigned long index = spaceid >> SPACEID_SHIFT;
      unsigned long *dirty_space_offset;

      dirty_space_offset = dirty_space_id + (index >> SHIFT_PER_LONG);
      index &= (BITS_PER_LONG - 1);

      spin_lock(&sid_lock);

      BUG_ON(*dirty_space_offset & (1L << index)); /* attempt to free space id twice */

      *dirty_space_offset |= (1L << index);
      dirty_space_ids++;

      spin_unlock(&sid_lock);
}


#ifdef CONFIG_SMP
static void get_dirty_sids(unsigned long *ndirtyptr,unsigned long *dirty_array)
{
      int i;

      /* NOTE: sid_lock must be held upon entry */

      *ndirtyptr = dirty_space_ids;
      if (dirty_space_ids != 0) {
          for (i = 0; i < SID_ARRAY_SIZE; i++) {
            dirty_array[i] = dirty_space_id[i];
            dirty_space_id[i] = 0;
          }
          dirty_space_ids = 0;
      }

      return;
}

static void recycle_sids(unsigned long ndirty,unsigned long *dirty_array)
{
      int i;

      /* NOTE: sid_lock must be held upon entry */

      if (ndirty != 0) {
            for (i = 0; i < SID_ARRAY_SIZE; i++) {
                  space_id[i] ^= dirty_array[i];
            }

            free_space_ids += ndirty;
            space_id_index = 0;
      }
}

#else /* CONFIG_SMP */

static void recycle_sids(void)
{
      int i;

      /* NOTE: sid_lock must be held upon entry */

      if (dirty_space_ids != 0) {
            for (i = 0; i < SID_ARRAY_SIZE; i++) {
                  space_id[i] ^= dirty_space_id[i];
                  dirty_space_id[i] = 0;
            }

            free_space_ids += dirty_space_ids;
            dirty_space_ids = 0;
            space_id_index = 0;
      }
}
#endif

/*
 * flush_tlb_all() calls recycle_sids(), since whenever the entire tlb is
 * purged, we can safely reuse the space ids that were released but
 * not flushed from the tlb.
 */

#ifdef CONFIG_SMP

static unsigned long recycle_ndirty;
static unsigned long recycle_dirty_array[SID_ARRAY_SIZE];
static unsigned int recycle_inuse;

void flush_tlb_all(void)
{
      int do_recycle;

      do_recycle = 0;
      spin_lock(&sid_lock);
      if (dirty_space_ids > RECYCLE_THRESHOLD) {
          BUG_ON(recycle_inuse);  /* FIXME: Use a semaphore/wait queue here */
          get_dirty_sids(&recycle_ndirty,recycle_dirty_array);
          recycle_inuse++;
          do_recycle++;
      }
      spin_unlock(&sid_lock);
      on_each_cpu(flush_tlb_all_local, NULL, 1);
      if (do_recycle) {
          spin_lock(&sid_lock);
          recycle_sids(recycle_ndirty,recycle_dirty_array);
          recycle_inuse = 0;
          spin_unlock(&sid_lock);
      }
}
#else
void flush_tlb_all(void)
{
      spin_lock(&sid_lock);
      flush_tlb_all_local(NULL);
      recycle_sids();
      spin_unlock(&sid_lock);
}
#endif

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
      if (start >= end)
            return;
      printk(KERN_INFO "Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
      for (; start < end; start += PAGE_SIZE) {
            ClearPageReserved(virt_to_page(start));
            init_page_count(virt_to_page(start));
            free_page(start);
            num_physpages++;
            totalram_pages++;
      }
}
#endif

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