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init.c

/*
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * 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/mm.h>
#include <linux/swap.h>
#include <linux/init.h>
#include <linux/mmzone.h>
#include <linux/module.h>
#include <linux/bootmem.h>
#include <linux/pagemap.h>
#include <linux/nodemask.h>

#include <asm/page.h>
#include <asm/mmu_context.h>
#include <asm/tlb.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/setup.h>
#include <asm/sections.h>

#define __page_aligned  __attribute__((section(".data.page_aligned")))

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned;

struct page *empty_zero_page;
EXPORT_SYMBOL(empty_zero_page);

/*
 * Cache of MMU context last used.
 */
unsigned long mmu_context_cache = NO_CONTEXT;

/*
 * paging_init() sets up the page tables
 *
 * This routine also unmaps the page at virtual kernel address 0, so
 * that we can trap those pesky NULL-reference errors in the kernel.
 */
void __init paging_init(void)
{
      extern unsigned long _evba;
      void *zero_page;
      int nid;

      /*
       * Make sure we can handle exceptions before enabling
       * paging. Not that we should ever _get_ any exceptions this
       * early, but you never know...
       */
      printk("Exception vectors start at %p\n", &_evba);
      sysreg_write(EVBA, (unsigned long)&_evba);

      /*
       * Since we are ready to handle exceptions now, we should let
       * the CPU generate them...
       */
      __asm__ __volatile__ ("csrf %0" : : "i"(SR_EM_BIT));

      /*
       * Allocate the zero page. The allocator will panic if it
       * can't satisfy the request, so no need to check.
       */
      zero_page = alloc_bootmem_low_pages_node(NODE_DATA(0),
                                     PAGE_SIZE);

      sysreg_write(PTBR, (unsigned long)swapper_pg_dir);
      enable_mmu();
      printk ("CPU: Paging enabled\n");

      for_each_online_node(nid) {
            pg_data_t *pgdat = NODE_DATA(nid);
            unsigned long zones_size[MAX_NR_ZONES];
            unsigned long low, start_pfn;

            start_pfn = pgdat->bdata->node_min_pfn;
            low = pgdat->bdata->node_low_pfn;

            memset(zones_size, 0, sizeof(zones_size));
            zones_size[ZONE_NORMAL] = low - start_pfn;

            printk("Node %u: start_pfn = 0x%lx, low = 0x%lx\n",
                   nid, start_pfn, low);

            free_area_init_node(nid, zones_size, start_pfn, NULL);

            printk("Node %u: mem_map starts at %p\n",
                   pgdat->node_id, pgdat->node_mem_map);
      }

      mem_map = NODE_DATA(0)->node_mem_map;

      memset(zero_page, 0, PAGE_SIZE);
      empty_zero_page = virt_to_page(zero_page);
      flush_dcache_page(empty_zero_page);
}

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

      reservedpages = 0;
      high_memory = NULL;

      /* this will put all low memory onto the freelists */
      for_each_online_node(nid) {
            pg_data_t *pgdat = NODE_DATA(nid);
            unsigned long node_pages = 0;
            void *node_high_memory;

            num_physpages += pgdat->node_present_pages;

            if (pgdat->node_spanned_pages != 0)
                  node_pages = free_all_bootmem_node(pgdat);

            totalram_pages += node_pages;

            for (i = 0; i < node_pages; i++)
                  if (PageReserved(pgdat->node_mem_map + i))
                        reservedpages++;

            node_high_memory = (void *)((pgdat->node_start_pfn
                                   + pgdat->node_spanned_pages)
                                  << PAGE_SHIFT);
            if (node_high_memory > high_memory)
                  high_memory = node_high_memory;
      }

      max_mapnr = MAP_NR(high_memory);

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

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

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 (%lx - %lx)\n",
                   s, size, end - (size << 10), end);
}

void free_initmem(void)
{
      free_area((unsigned long)__init_begin, (unsigned long)__init_end,
              "init");
}

#ifdef CONFIG_BLK_DEV_INITRD

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

#endif

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