pgtable_32.c

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#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/nmi.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/spinlock.h>
#include <linux/module.h>

#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/fixmap.h>
#include <asm/e820.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/io.h>

unsigned int __VMALLOC_RESERVE = 128 << 20;

/*
 * Associate a virtual page frame with a given physical page frame 
 * and protection flags for that frame.
 */ 
void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
{
    pgd_t *pgd;
    pud_t *pud;
    pmd_t *pmd;
    pte_t *pte;

    pgd = swapper_pg_dir + pgd_index(vaddr);
    if (pgd_none(*pgd)) {
        BUG();
        return;
    }
    pud = pud_offset(pgd, vaddr);
    if (pud_none(*pud)) {
        BUG();
        return;
    }
    pmd = pmd_offset(pud, vaddr);
    if (pmd_none(*pmd)) {
        BUG();
        return;
    }
    pte = pte_offset_kernel(pmd, vaddr);
    if (pte_val(pteval))
        set_pte_at(&init_mm, vaddr, pte, pteval);
    else
        pte_clear(&init_mm, vaddr, pte);

    /*
     * It's enough to flush this one mapping.
     * (PGE mappings get flushed as well)
     */
    __flush_tlb_one(vaddr);
}

/*
 * Associate a large virtual page frame with a given physical page frame 
 * and protection flags for that frame. pfn is for the base of the page,
 * vaddr is what the page gets mapped to - both must be properly aligned. 
 * The pmd must already be instantiated. Assumes PAE mode.
 */ 
void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
{
    pgd_t *pgd;
    pud_t *pud;
    pmd_t *pmd;

    if (vaddr & (PMD_SIZE-1)) {     /* vaddr is misaligned */
        printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
        return; /* BUG(); */
    }
    if (pfn & (PTRS_PER_PTE-1)) {       /* pfn is misaligned */
        printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
        return; /* BUG(); */
    }
    pgd = swapper_pg_dir + pgd_index(vaddr);
    if (pgd_none(*pgd)) {
        printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
        return; /* BUG(); */
    }
    pud = pud_offset(pgd, vaddr);
    pmd = pmd_offset(pud, vaddr);
    set_pmd(pmd, pfn_pmd(pfn, flags));
    /*
     * It's enough to flush this one mapping.
     * (PGE mappings get flushed as well)
     */
    __flush_tlb_one(vaddr);
}

unsigned long __FIXADDR_TOP = 0xfffff000;
EXPORT_SYMBOL(__FIXADDR_TOP);

/*
 * vmalloc=size forces the vmalloc area to be exactly 'size'
 * bytes. This can be used to increase (or decrease) the
 * vmalloc area - the default is 128m.
 */
static int __init parse_vmalloc(char *arg)
{
    if (!arg)
        return -EINVAL;

    /* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
    __VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
    return 0;
}
early_param("vmalloc", parse_vmalloc);

/*
 * reservetop=size reserves a hole at the top of the kernel address space which
 * a hypervisor can load into later.  Needed for dynamically loaded hypervisors,
 * so relocating the fixmap can be done before paging initialization.
 */
static int __init parse_reservetop(char *arg)
{
    unsigned long address;

    if (!arg)
        return -EINVAL;

    address = memparse(arg, &arg);
    reserve_top_address(address);
    fixup_early_ioremap();
    return 0;
}
early_param("reservetop", parse_reservetop);