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init.c

/*
 *  linux/arch/arm/mm/init.c
 *
 *  Copyright (C) 1995-2005 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/swap.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/mman.h>
#include <linux/nodemask.h>
#include <linux/initrd.h>

#include <asm/mach-types.h>
#include <asm/setup.h>
#include <asm/sizes.h>
#include <asm/tlb.h>

#include <asm/mach/arch.h>
#include <asm/mach/map.h>

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
extern void _stext, _text, _etext, __data_start, _end, __init_begin, __init_end;
extern unsigned long phys_initrd_start;
extern unsigned long phys_initrd_size;

/*
 * The sole use of this is to pass memory configuration
 * data from paging_init to mem_init.
 */
static struct meminfo meminfo __initdata = { 0, };

/*
 * empty_zero_page is a special page that is used for
 * zero-initialized data and COW.
 */
struct page *empty_zero_page;

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

      printk("Mem-info:\n");
      show_free_areas();
      printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));

      for_each_online_node(node) {
            struct page *page, *end;

            page = NODE_MEM_MAP(node);
            end  = page + NODE_DATA(node)->node_spanned_pages;

            do {
                  total++;
                  if (PageReserved(page))
                        reserved++;
                  else if (PageSwapCache(page))
                        cached++;
                  else if (PageSlab(page))
                        slab++;
                  else if (!page_count(page))
                        free++;
                  else
                        shared += page_count(page) - 1;
                  page++;
            } while (page < end);
      }

      printk("%d pages of RAM\n", total);
      printk("%d free pages\n", free);
      printk("%d reserved pages\n", reserved);
      printk("%d slab pages\n", slab);
      printk("%d pages shared\n", shared);
      printk("%d pages swap cached\n", cached);
}

static inline pmd_t *pmd_off(pgd_t *pgd, unsigned long virt)
{
      return pmd_offset(pgd, virt);
}

static inline pmd_t *pmd_off_k(unsigned long virt)
{
      return pmd_off(pgd_offset_k(virt), virt);
}

#define for_each_nodebank(iter,mi,no)                 \
      for (iter = 0; iter < mi->nr_banks; iter++)     \
            if (mi->bank[iter].node == no)

/*
 * FIXME: We really want to avoid allocating the bootmap bitmap
 * over the top of the initrd.  Hopefully, this is located towards
 * the start of a bank, so if we allocate the bootmap bitmap at
 * the end, we won't clash.
 */
static unsigned int __init
find_bootmap_pfn(int node, struct meminfo *mi, unsigned int bootmap_pages)
{
      unsigned int start_pfn, bank, bootmap_pfn;

      start_pfn   = PAGE_ALIGN(__pa(&_end)) >> PAGE_SHIFT;
      bootmap_pfn = 0;

      for_each_nodebank(bank, mi, node) {
            unsigned int start, end;

            start = mi->bank[bank].start >> PAGE_SHIFT;
            end   = (mi->bank[bank].size +
                   mi->bank[bank].start) >> PAGE_SHIFT;

            if (end < start_pfn)
                  continue;

            if (start < start_pfn)
                  start = start_pfn;

            if (end <= start)
                  continue;

            if (end - start >= bootmap_pages) {
                  bootmap_pfn = start;
                  break;
            }
      }

      if (bootmap_pfn == 0)
            BUG();

      return bootmap_pfn;
}

static int __init check_initrd(struct meminfo *mi)
{
      int initrd_node = -2;
#ifdef CONFIG_BLK_DEV_INITRD
      unsigned long end = phys_initrd_start + phys_initrd_size;

      /*
       * Make sure that the initrd is within a valid area of
       * memory.
       */
      if (phys_initrd_size) {
            unsigned int i;

            initrd_node = -1;

            for (i = 0; i < mi->nr_banks; i++) {
                  unsigned long bank_end;

                  bank_end = mi->bank[i].start + mi->bank[i].size;

                  if (mi->bank[i].start <= phys_initrd_start &&
                      end <= bank_end)
                        initrd_node = mi->bank[i].node;
            }
      }

      if (initrd_node == -1) {
            printk(KERN_ERR "initrd (0x%08lx - 0x%08lx) extends beyond "
                   "physical memory - disabling initrd\n",
                   phys_initrd_start, end);
            phys_initrd_start = phys_initrd_size = 0;
      }
#endif

      return initrd_node;
}

/*
 * Reserve the various regions of node 0
 */
static __init void reserve_node_zero(pg_data_t *pgdat)
{
      unsigned long res_size = 0;

      /*
       * Register the kernel text and data with bootmem.
       * Note that this can only be in node 0.
       */
#ifdef CONFIG_XIP_KERNEL
      reserve_bootmem_node(pgdat, __pa(&__data_start), &_end - &__data_start);
#else
      reserve_bootmem_node(pgdat, __pa(&_stext), &_end - &_stext);
#endif

      /*
       * Reserve the page tables.  These are already in use,
       * and can only be in node 0.
       */
      reserve_bootmem_node(pgdat, __pa(swapper_pg_dir),
                       PTRS_PER_PGD * sizeof(pgd_t));

      /*
       * Hmm... This should go elsewhere, but we really really need to
       * stop things allocating the low memory; ideally we need a better
       * implementation of GFP_DMA which does not assume that DMA-able
       * memory starts at zero.
       */
      if (machine_is_integrator() || machine_is_cintegrator())
            res_size = __pa(swapper_pg_dir) - PHYS_OFFSET;

      /*
       * These should likewise go elsewhere.  They pre-reserve the
       * screen memory region at the start of main system memory.
       */
      if (machine_is_edb7211())
            res_size = 0x00020000;
      if (machine_is_p720t())
            res_size = 0x00014000;

#ifdef CONFIG_SA1111
      /*
       * Because of the SA1111 DMA bug, we want to preserve our
       * precious DMA-able memory...
       */
      res_size = __pa(swapper_pg_dir) - PHYS_OFFSET;
#endif
      if (res_size)
            reserve_bootmem_node(pgdat, PHYS_OFFSET, res_size);
}

void __init build_mem_type_table(void);
void __init create_mapping(struct map_desc *md);

static unsigned long __init
bootmem_init_node(int node, int initrd_node, struct meminfo *mi)
{
      unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
      unsigned long start_pfn, end_pfn, boot_pfn;
      unsigned int boot_pages;
      pg_data_t *pgdat;
      int i;

      start_pfn = -1UL;
      end_pfn = 0;

      /*
       * Calculate the pfn range, and map the memory banks for this node.
       */
      for_each_nodebank(i, mi, node) {
            unsigned long start, end;
            struct map_desc map;

            start = mi->bank[i].start >> PAGE_SHIFT;
            end = (mi->bank[i].start + mi->bank[i].size) >> PAGE_SHIFT;

            if (start_pfn > start)
                  start_pfn = start;
            if (end_pfn < end)
                  end_pfn = end;

            map.pfn = __phys_to_pfn(mi->bank[i].start);
            map.virtual = __phys_to_virt(mi->bank[i].start);
            map.length = mi->bank[i].size;
            map.type = MT_MEMORY;

            create_mapping(&map);
      }

      /*
       * If there is no memory in this node, ignore it.
       */
      if (end_pfn == 0)
            return end_pfn;

      /*
       * Allocate the bootmem bitmap page.
       */
      boot_pages = bootmem_bootmap_pages(end_pfn - start_pfn);
      boot_pfn = find_bootmap_pfn(node, mi, boot_pages);

      /*
       * Initialise the bootmem allocator for this node, handing the
       * memory banks over to bootmem.
       */
      node_set_online(node);
      pgdat = NODE_DATA(node);
      init_bootmem_node(pgdat, boot_pfn, start_pfn, end_pfn);

      for_each_nodebank(i, mi, node)
            free_bootmem_node(pgdat, mi->bank[i].start, mi->bank[i].size);

      /*
       * Reserve the bootmem bitmap for this node.
       */
      reserve_bootmem_node(pgdat, boot_pfn << PAGE_SHIFT,
                       boot_pages << PAGE_SHIFT);

#ifdef CONFIG_BLK_DEV_INITRD
      /*
       * If the initrd is in this node, reserve its memory.
       */
      if (node == initrd_node) {
            reserve_bootmem_node(pgdat, phys_initrd_start,
                             phys_initrd_size);
            initrd_start = __phys_to_virt(phys_initrd_start);
            initrd_end = initrd_start + phys_initrd_size;
      }
#endif

      /*
       * Finally, reserve any node zero regions.
       */
      if (node == 0)
            reserve_node_zero(pgdat);

      /*
       * initialise the zones within this node.
       */
      memset(zone_size, 0, sizeof(zone_size));
      memset(zhole_size, 0, sizeof(zhole_size));

      /*
       * The size of this node has already been determined.  If we need
       * to do anything fancy with the allocation of this memory to the
       * zones, now is the time to do it.
       */
      zone_size[0] = end_pfn - start_pfn;

      /*
       * For each bank in this node, calculate the size of the holes.
       *  holes = node_size - sum(bank_sizes_in_node)
       */
      zhole_size[0] = zone_size[0];
      for_each_nodebank(i, mi, node)
            zhole_size[0] -= mi->bank[i].size >> PAGE_SHIFT;

      /*
       * Adjust the sizes according to any special requirements for
       * this machine type.
       */
      arch_adjust_zones(node, zone_size, zhole_size);

      free_area_init_node(node, pgdat, zone_size, start_pfn, zhole_size);

      return end_pfn;
}

static void __init bootmem_init(struct meminfo *mi)
{
      unsigned long addr, memend_pfn = 0;
      int node, initrd_node, i;

      /*
       * Invalidate the node number for empty or invalid memory banks
       */
      for (i = 0; i < mi->nr_banks; i++)
            if (mi->bank[i].size == 0 || mi->bank[i].node >= MAX_NUMNODES)
                  mi->bank[i].node = -1;

      memcpy(&meminfo, mi, sizeof(meminfo));

      /*
       * Clear out all the mappings below the kernel image.
       */
      for (addr = 0; addr < MODULE_START; addr += PGDIR_SIZE)
            pmd_clear(pmd_off_k(addr));
#ifdef CONFIG_XIP_KERNEL
      /* The XIP kernel is mapped in the module area -- skip over it */
      addr = ((unsigned long)&_etext + PGDIR_SIZE - 1) & PGDIR_MASK;
#endif
      for ( ; addr < PAGE_OFFSET; addr += PGDIR_SIZE)
            pmd_clear(pmd_off_k(addr));

      /*
       * Clear out all the kernel space mappings, except for the first
       * memory bank, up to the end of the vmalloc region.
       */
      for (addr = __phys_to_virt(mi->bank[0].start + mi->bank[0].size);
           addr < VMALLOC_END; addr += PGDIR_SIZE)
            pmd_clear(pmd_off_k(addr));

      /*
       * Locate which node contains the ramdisk image, if any.
       */
      initrd_node = check_initrd(mi);

      /*
       * Run through each node initialising the bootmem allocator.
       */
      for_each_node(node) {
            unsigned long end_pfn;

            end_pfn = bootmem_init_node(node, initrd_node, mi);

            /*
             * Remember the highest memory PFN.
             */
            if (end_pfn > memend_pfn)
                  memend_pfn = end_pfn;
      }

      high_memory = __va(memend_pfn << PAGE_SHIFT);

      /*
       * This doesn't seem to be used by the Linux memory manager any
       * more, but is used by ll_rw_block.  If we can get rid of it, we
       * also get rid of some of the stuff above as well.
       *
       * Note: max_low_pfn and max_pfn reflect the number of _pages_ in
       * the system, not the maximum PFN.
       */
      max_pfn = max_low_pfn = memend_pfn - PHYS_PFN_OFFSET;
}

/*
 * Set up device the mappings.  Since we clear out the page tables for all
 * mappings above VMALLOC_END, we will remove any debug device mappings.
 * This means you have to be careful how you debug this function, or any
 * called function.  This means you can't use any function or debugging
 * method which may touch any device, otherwise the kernel _will_ crash.
 */
static void __init devicemaps_init(struct machine_desc *mdesc)
{
      struct map_desc map;
      unsigned long addr;
      void *vectors;

      /*
       * Allocate the vector page early.
       */
      vectors = alloc_bootmem_low_pages(PAGE_SIZE);
      BUG_ON(!vectors);

      for (addr = VMALLOC_END; addr; addr += PGDIR_SIZE)
            pmd_clear(pmd_off_k(addr));

      /*
       * Map the kernel if it is XIP.
       * It is always first in the modulearea.
       */
#ifdef CONFIG_XIP_KERNEL
      map.pfn = __phys_to_pfn(CONFIG_XIP_PHYS_ADDR & PGDIR_MASK);
      map.virtual = MODULE_START;
      map.length = ((unsigned long)&_etext - map.virtual + ~PGDIR_MASK) & PGDIR_MASK;
      map.type = MT_ROM;
      create_mapping(&map);
#endif

      /*
       * Map the cache flushing regions.
       */
#ifdef FLUSH_BASE
      map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS);
      map.virtual = FLUSH_BASE;
      map.length = SZ_1M;
      map.type = MT_CACHECLEAN;
      create_mapping(&map);
#endif
#ifdef FLUSH_BASE_MINICACHE
      map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS + SZ_1M);
      map.virtual = FLUSH_BASE_MINICACHE;
      map.length = SZ_1M;
      map.type = MT_MINICLEAN;
      create_mapping(&map);
#endif

      /*
       * Create a mapping for the machine vectors at the high-vectors
       * location (0xffff0000).  If we aren't using high-vectors, also
       * create a mapping at the low-vectors virtual address.
       */
      map.pfn = __phys_to_pfn(virt_to_phys(vectors));
      map.virtual = 0xffff0000;
      map.length = PAGE_SIZE;
      map.type = MT_HIGH_VECTORS;
      create_mapping(&map);

      if (!vectors_high()) {
            map.virtual = 0;
            map.type = MT_LOW_VECTORS;
            create_mapping(&map);
      }

      /*
       * Ask the machine support to map in the statically mapped devices.
       */
      if (mdesc->map_io)
            mdesc->map_io();

      /*
       * Finally flush the caches and tlb to ensure that we're in a
       * consistent state wrt the writebuffer.  This also ensures that
       * any write-allocated cache lines in the vector page are written
       * back.  After this point, we can start to touch devices again.
       */
      local_flush_tlb_all();
      flush_cache_all();
}

/*
 * paging_init() sets up the page tables, initialises the zone memory
 * maps, and sets up the zero page, bad page and bad page tables.
 */
void __init paging_init(struct meminfo *mi, struct machine_desc *mdesc)
{
      void *zero_page;

      build_mem_type_table();
      bootmem_init(mi);
      devicemaps_init(mdesc);

      top_pmd = pmd_off_k(0xffff0000);

      /*
       * allocate the zero page.  Note that we count on this going ok.
       */
      zero_page = alloc_bootmem_low_pages(PAGE_SIZE);
      memzero(zero_page, PAGE_SIZE);
      empty_zero_page = virt_to_page(zero_page);
      flush_dcache_page(empty_zero_page);
}

static inline void free_area(unsigned long addr, unsigned long end, char *s)
{
      unsigned int size = (end - addr) >> 10;

      for (; addr < end; addr += PAGE_SIZE) {
            struct page *page = virt_to_page(addr);
            ClearPageReserved(page);
            init_page_count(page);
            free_page(addr);
            totalram_pages++;
      }

      if (size && s)
            printk(KERN_INFO "Freeing %s memory: %dK\n", s, size);
}

static inline void
free_memmap(int node, unsigned long start_pfn, unsigned long end_pfn)
{
      struct page *start_pg, *end_pg;
      unsigned long pg, pgend;

      /*
       * Convert start_pfn/end_pfn to a struct page pointer.
       */
      start_pg = pfn_to_page(start_pfn);
      end_pg = pfn_to_page(end_pfn);

      /*
       * Convert to physical addresses, and
       * round start upwards and end downwards.
       */
      pg = PAGE_ALIGN(__pa(start_pg));
      pgend = __pa(end_pg) & PAGE_MASK;

      /*
       * If there are free pages between these,
       * free the section of the memmap array.
       */
      if (pg < pgend)
            free_bootmem_node(NODE_DATA(node), pg, pgend - pg);
}

/*
 * The mem_map array can get very big.  Free the unused area of the memory map.
 */
static void __init free_unused_memmap_node(int node, struct meminfo *mi)
{
      unsigned long bank_start, prev_bank_end = 0;
      unsigned int i;

      /*
       * [FIXME] This relies on each bank being in address order.  This
       * may not be the case, especially if the user has provided the
       * information on the command line.
       */
      for_each_nodebank(i, mi, node) {
            bank_start = mi->bank[i].start >> PAGE_SHIFT;
            if (bank_start < prev_bank_end) {
                  printk(KERN_ERR "MEM: unordered memory banks.  "
                        "Not freeing memmap.\n");
                  break;
            }

            /*
             * If we had a previous bank, and there is a space
             * between the current bank and the previous, free it.
             */
            if (prev_bank_end && prev_bank_end != bank_start)
                  free_memmap(node, prev_bank_end, bank_start);

            prev_bank_end = (mi->bank[i].start +
                         mi->bank[i].size) >> PAGE_SHIFT;
      }
}

/*
 * mem_init() marks the free areas in the mem_map and tells us how much
 * memory is free.  This is done after various parts of the system have
 * claimed their memory after the kernel image.
 */
void __init mem_init(void)
{
      unsigned int codepages, datapages, initpages;
      int i, node;

      codepages = &_etext - &_text;
      datapages = &_end - &__data_start;
      initpages = &__init_end - &__init_begin;

#ifndef CONFIG_DISCONTIGMEM
      max_mapnr   = virt_to_page(high_memory) - mem_map;
#endif

      /* this will put all unused low memory onto the freelists */
      for_each_online_node(node) {
            pg_data_t *pgdat = NODE_DATA(node);

            free_unused_memmap_node(node, &meminfo);

            if (pgdat->node_spanned_pages != 0)
                  totalram_pages += free_all_bootmem_node(pgdat);
      }

#ifdef CONFIG_SA1111
      /* now that our DMA memory is actually so designated, we can free it */
      free_area(PAGE_OFFSET, (unsigned long)swapper_pg_dir, NULL);
#endif

      /*
       * Since our memory may not be contiguous, calculate the
       * real number of pages we have in this system
       */
      printk(KERN_INFO "Memory:");

      num_physpages = 0;
      for (i = 0; i < meminfo.nr_banks; i++) {
            num_physpages += meminfo.bank[i].size >> PAGE_SHIFT;
            printk(" %ldMB", meminfo.bank[i].size >> 20);
      }

      printk(" = %luMB total\n", num_physpages >> (20 - PAGE_SHIFT));
      printk(KERN_NOTICE "Memory: %luKB available (%dK code, "
            "%dK data, %dK init)\n",
            (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
            codepages >> 10, datapages >> 10, initpages >> 10);

      if (PAGE_SIZE >= 16384 && num_physpages <= 128) {
            extern int sysctl_overcommit_memory;
            /*
             * On a machine this small we won't get
             * anywhere without overcommit, so turn
             * it on by default.
             */
            sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
      }
}

void free_initmem(void)
{
      if (!machine_is_integrator() && !machine_is_cintegrator()) {
            free_area((unsigned long)(&__init_begin),
                    (unsigned long)(&__init_end),
                    "init");
      }
}

#ifdef CONFIG_BLK_DEV_INITRD

static int keep_initrd;

void free_initrd_mem(unsigned long start, unsigned long end)
{
      if (!keep_initrd)
            free_area(start, end, "initrd");
}

static int __init keepinitrd_setup(char *__unused)
{
      keep_initrd = 1;
      return 1;
}

__setup("keepinitrd", keepinitrd_setup);
#endif

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