linux/arch/x86/mm/pgtable_32.c
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   1#include <linux/sched.h>
   2#include <linux/kernel.h>
   3#include <linux/errno.h>
   4#include <linux/mm.h>
   5#include <linux/nmi.h>
   6#include <linux/swap.h>
   7#include <linux/smp.h>
   8#include <linux/highmem.h>
   9#include <linux/slab.h>
  10#include <linux/pagemap.h>
  11#include <linux/spinlock.h>
  12#include <linux/module.h>
  13#include <linux/quicklist.h>
  14
  15#include <asm/system.h>
  16#include <asm/pgtable.h>
  17#include <asm/pgalloc.h>
  18#include <asm/fixmap.h>
  19#include <asm/e820.h>
  20#include <asm/tlb.h>
  21#include <asm/tlbflush.h>
  22
  23/*
  24 * Associate a virtual page frame with a given physical page frame 
  25 * and protection flags for that frame.
  26 */ 
  27void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
  28{
  29        pgd_t *pgd;
  30        pud_t *pud;
  31        pmd_t *pmd;
  32        pte_t *pte;
  33
  34        pgd = swapper_pg_dir + pgd_index(vaddr);
  35        if (pgd_none(*pgd)) {
  36                BUG();
  37                return;
  38        }
  39        pud = pud_offset(pgd, vaddr);
  40        if (pud_none(*pud)) {
  41                BUG();
  42                return;
  43        }
  44        pmd = pmd_offset(pud, vaddr);
  45        if (pmd_none(*pmd)) {
  46                BUG();
  47                return;
  48        }
  49        pte = pte_offset_kernel(pmd, vaddr);
  50        if (pte_val(pteval))
  51                set_pte_present(&init_mm, vaddr, pte, pteval);
  52        else
  53                pte_clear(&init_mm, vaddr, pte);
  54
  55        /*
  56         * It's enough to flush this one mapping.
  57         * (PGE mappings get flushed as well)
  58         */
  59        __flush_tlb_one(vaddr);
  60}
  61
  62/*
  63 * Associate a large virtual page frame with a given physical page frame 
  64 * and protection flags for that frame. pfn is for the base of the page,
  65 * vaddr is what the page gets mapped to - both must be properly aligned. 
  66 * The pmd must already be instantiated. Assumes PAE mode.
  67 */ 
  68void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
  69{
  70        pgd_t *pgd;
  71        pud_t *pud;
  72        pmd_t *pmd;
  73
  74        if (vaddr & (PMD_SIZE-1)) {             /* vaddr is misaligned */
  75                printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
  76                return; /* BUG(); */
  77        }
  78        if (pfn & (PTRS_PER_PTE-1)) {           /* pfn is misaligned */
  79                printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
  80                return; /* BUG(); */
  81        }
  82        pgd = swapper_pg_dir + pgd_index(vaddr);
  83        if (pgd_none(*pgd)) {
  84                printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
  85                return; /* BUG(); */
  86        }
  87        pud = pud_offset(pgd, vaddr);
  88        pmd = pmd_offset(pud, vaddr);
  89        set_pmd(pmd, pfn_pmd(pfn, flags));
  90        /*
  91         * It's enough to flush this one mapping.
  92         * (PGE mappings get flushed as well)
  93         */
  94        __flush_tlb_one(vaddr);
  95}
  96
  97unsigned long __FIXADDR_TOP = 0xfffff000;
  98EXPORT_SYMBOL(__FIXADDR_TOP);
  99
 100/**
 101 * reserve_top_address - reserves a hole in the top of kernel address space
 102 * @reserve - size of hole to reserve
 103 *
 104 * Can be used to relocate the fixmap area and poke a hole in the top
 105 * of kernel address space to make room for a hypervisor.
 106 */
 107void __init reserve_top_address(unsigned long reserve)
 108{
 109        BUG_ON(fixmaps_set > 0);
 110        printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
 111               (int)-reserve);
 112        __FIXADDR_TOP = -reserve - PAGE_SIZE;
 113        __VMALLOC_RESERVE += reserve;
 114}
 115
 116/*
 117 * vmalloc=size forces the vmalloc area to be exactly 'size'
 118 * bytes. This can be used to increase (or decrease) the
 119 * vmalloc area - the default is 128m.
 120 */
 121static int __init parse_vmalloc(char *arg)
 122{
 123        if (!arg)
 124                return -EINVAL;
 125
 126        /* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
 127        __VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
 128        return 0;
 129}
 130early_param("vmalloc", parse_vmalloc);
 131
 132/*
 133 * reservetop=size reserves a hole at the top of the kernel address space which
 134 * a hypervisor can load into later.  Needed for dynamically loaded hypervisors,
 135 * so relocating the fixmap can be done before paging initialization.
 136 */
 137static int __init parse_reservetop(char *arg)
 138{
 139        unsigned long address;
 140
 141        if (!arg)
 142                return -EINVAL;
 143
 144        address = memparse(arg, &arg);
 145        reserve_top_address(address);
 146        return 0;
 147}
 148early_param("reservetop", parse_reservetop);
 149