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
  12 #include <asm/pgtable.h>
  13 #include <asm/pgalloc.h>
  14 #include <asm/fixmap.h>
  15 #include <asm/e820/api.h>
  16 #include <asm/tlb.h>
  17 #include <asm/tlbflush.h>
  18 #include <asm/io.h>
  19
  20 unsigned int __VMALLOC_RESERVE = 128 << 20;
  21
  22 /*
  23  * Associate a virtual page frame with a given physical page frame
  24  * and protection flags for that frame.
  25  */
  26 void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
  27 {
  28         pgd_t *pgd;
  29         p4d_t *p4d;
  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         p4d = p4d_offset(pgd, vaddr);
  40         if (p4d_none(*p4d)) {
  41                 BUG();
  42                 return;
  43         }
  44         pud = pud_offset(p4d, vaddr);
  45         if (pud_none(*pud)) {
  46                 BUG();
  47                 return;
  48         }
  49         pmd = pmd_offset(pud, vaddr);
  50         if (pmd_none(*pmd)) {
  51                 BUG();
  52                 return;
  53         }
  54         pte = pte_offset_kernel(pmd, vaddr);
  55         if (!pte_none(pteval))
  56                 set_pte_at(&init_mm, vaddr, pte, pteval);
  57         else
  58                 pte_clear(&init_mm, vaddr, pte);
  59
  60         /*
  61          * It's enough to flush this one mapping.
  62          * (PGE mappings get flushed as well)
  63          */
  64         __flush_tlb_one(vaddr);
  65 }
  66
  67 unsigned long __FIXADDR_TOP = 0xfffff000;
  68 EXPORT_SYMBOL(__FIXADDR_TOP);
  69
  70 /*
  71  * vmalloc=size forces the vmalloc area to be exactly 'size'
  72  * bytes. This can be used to increase (or decrease) the
  73  * vmalloc area - the default is 128m.
  74  */
  75 static int __init parse_vmalloc(char *arg)
  76 {
  77         if (!arg)
  78                 return -EINVAL;
  79
  80         /* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
  81         __VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
  82         return 0;
  83 }
  84 early_param("vmalloc", parse_vmalloc);
  85
  86 /*
  87  * reservetop=size reserves a hole at the top of the kernel address space which
  88  * a hypervisor can load into later.  Needed for dynamically loaded hypervisors,
  89  * so relocating the fixmap can be done before paging initialization.
  90  */
  91 static int __init parse_reservetop(char *arg)
  92 {
  93         unsigned long address;
  94
  95         if (!arg)
  96                 return -EINVAL;
  97
  98         address = memparse(arg, &arg);
  99         reserve_top_address(address);
 100         early_ioremap_init();
 101         return 0;
 102 }
 103 early_param("reservetop", parse_reservetop);