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/memblock.h>
#include <linux/proc_fs.h>
#include <linux/memory_hotplug.h>
#include <linux/initrd.h>
#include <linux/cpumask.h>
#include <linux/gfp.h>

#include <asm/asm.h>
#include <asm/bios_ebda.h>
#include <asm/processor.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/olpc_ofw.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/paravirt.h>
#include <asm/setup.h>
#include <asm/cacheflush.h>
#include <asm/page_types.h>
#include <asm/init.h>

#include "mm_internal.h"

unsigned long highstart_pfn, highend_pfn;

static noinline int do_test_wp_bit(void);

bool __read_mostly __vmalloc_start_set = false;

/*
 * 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)) {
		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 = (pte_t *)alloc_low_page();

		paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
		set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
		BUG_ON(page_table != pte_offset_kernel(pmd, 0));
	}

	return pte_offset_kernel(pmd, 0);
}

pmd_t * __init populate_extra_pmd(unsigned long vaddr)
{
	int pgd_idx = pgd_index(vaddr);
	int pmd_idx = pmd_index(vaddr);

	return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx;
}

pte_t * __init populate_extra_pte(unsigned long vaddr)
{
	int pte_idx = pte_index(vaddr);
	pmd_t *pmd;

	pmd = populate_extra_pmd(vaddr);
	return one_page_table_init(pmd) + pte_idx;
}

static unsigned long __init
page_table_range_init_count(unsigned long start, unsigned long end)
{
	unsigned long count = 0;
#ifdef CONFIG_HIGHMEM
	int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
	int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
	int pgd_idx, pmd_idx;
	unsigned long vaddr;

	if (pmd_idx_kmap_begin == pmd_idx_kmap_end)
		return 0;

	vaddr = start;
	pgd_idx = pgd_index(vaddr);

	for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) {
		for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
							pmd_idx++) {
			if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin &&
			    (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end)
				count++;
			vaddr += PMD_SIZE;
		}
		pmd_idx = 0;
	}
#endif
	return count;
}

static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
					   unsigned long vaddr, pte_t *lastpte,
					   void **adr)
{
#ifdef CONFIG_HIGHMEM
	/*
	 * Something (early fixmap) may already have put a pte
	 * page here, which causes the page table allocation
	 * to become nonlinear. Attempt to fi