path: root/arch/x86/mm/init_32.c

/*
 *
 *  Copyright (C) 1995  Linus Torvalds
 *
 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 */

#include <linux/module.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/pci.h>
#include <linux/pfn.h>
#include <linux/poison.h>
#include <linux/bootmem.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/memory_hotplug.h>
#include <linux/initrd.h>
#include <linux/cpumask.h>

#include <asm/asm.h>
#include <asm/bios_ebda.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/dma.h>
#include <asm/fixmap.h>
#include <asm/e820.h>
#include <asm/apic.h>
#include <asm/bugs.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/paravirt.h>
#include <asm/setup.h>
#include <asm/cacheflush.h>
#include <asm/smp.h>

unsigned int __VMALLOC_RESERVE = 128 << 20;

unsigned long max_low_pfn_mapped;
unsigned long max_pfn_mapped;

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
unsigned long highstart_pfn, highend_pfn;

static noinline int do_test_wp_bit(void);


static unsigned long __initdata table_start;
static unsigned long __meminitdata table_end;
static unsigned long __meminitdata table_top;

static int __initdata after_init_bootmem;

static __init void *alloc_low_page(void)
{
	unsigned long pfn = table_end++;
	void *adr;

	if (pfn >= table_top)
		panic("alloc_low_page: ran out of memory");

	adr = __va(pfn * PAGE_SIZE);
	memset(adr, 0, PAGE_SIZE);
	return adr;
}

/*
 * Creates a middle page table and puts a pointer to it in the
 * given global directory entry. This only returns the gd entry
 * in non-PAE compilation mode, since the middle layer is folded.
 */
static pmd_t * __init one_md_table_init(pgd_t *pgd)
{
	pud_t *pud;
	pmd_t *pmd_table;

#ifdef CONFIG_X86_PAE
	if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
		if (after_init_bootmem)
			pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
		else
			pmd_table = (pmd_t *)alloc_low_page();
		paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
		set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
		pud = pud_offset(pgd, 0);
		BUG_ON(pmd_table != pmd_offset(pud, 0));

		return pmd_table;
	}
#endif
	pud = pud_offset(pgd, 0);
	pmd_table = pmd_offset(pud, 0);

	return pmd_table;
}

/*
 * Create a page table and place a pointer to it in a middle page
 * directory entry:
 */
static pte_t * __init one_page_table_init(pmd_t *pmd)
{
	if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
		pte_t *page_table = NULL;