arch/x86/mm/pgtable_32.c

   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/pagemap.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/module.h>
  12
  13 #include <asm/pgtable.h>
  14 #include <asm/pgalloc.h>
  15 #include <asm/fixmap.h>
  16 #include <asm/e820.h>
  17 #include <asm/tlb.h>
  18 #include <asm/tlbflush.h>
  19 #include <asm/io.h>
  20
  21 unsigned int __VMALLOC_RESERVE = 128 << 20;
  22
  23 /*
  24  * Associate a virtual page frame with a given physical page frame
  25  * and protection flags for that frame.
  26  */
  27 void 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_at(&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 unsigned long __FIXADDR_TOP = 0xfffff000;
  63 EXPORT_SYMBOL(__FIXADDR_TOP);
  64
  65 /*
  66  * vmalloc=size forces the vmalloc area to be exactly 'size'
  67  * bytes. This can be used to increase (or decrease) the
  68  * vmalloc area - the default is 128m.
  69  */
  70 static int __init parse_vmalloc(char *arg)
  71 {
  72         if (!arg)
  73                 return -EINVAL;
  74
  75         /* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
  76         __VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
  77         return 0;
  78 }
  79 early_param("vmalloc", parse_vmalloc);
  80
  81 /*
  82  * reservetop=size reserves a hole at the top of the kernel address space which
  83  * a hypervisor can load into later.  Needed for dynamically loaded hypervisors,
  84  * so relocating the fixmap can be done before paging initialization.
  85  */
  86 static int __init parse_reservetop(char *arg)
  87 {
  88         unsigned long address;
  89
  90         if (!arg)
  91                 return -EINVAL;
  92
  93         address = memparse(arg, &arg);
  94         reserve_top_address(address);
  95         early_ioremap_init();
  96         return 0;
  97 }
  98 early_param("reservetop", parse_reservetop);