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.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         pud_t *pud;
  30         pmd_t *pmd;
  31         pte_t *pte;
  32
  33         pgd = swapper_pg_dir + pgd_index(vaddr);
  34         if (pgd_none(*pgd)) {
  35                 BUG();
  36                 return;
  37         }
  38         pud = pud_offset(pgd, vaddr);
  39         if (pud_none(*pud)) {
  40                 BUG();
  41                 return;
  42         }
  43         pmd = pmd_offset(pud, vaddr);
  44         if (pmd_none(*pmd)) {
  45                 BUG();
  46                 return;
  47         }
  48         pte = pte_offset_kernel(pmd, vaddr);
  49         if (!pte_none(pteval))
  50                 set_pte_at(&init_mm, vaddr, pte, pteval);
  51         else
  52                 pte_clear(&init_mm, vaddr, pte);
  53
  54         /*
  55          * It's enough to flush this one mapping.
  56          * (PGE mappings get flushed as well)
  57          */
  58         __flush_tlb_one(vaddr);
  59 }
  60
  61 unsigned long __FIXADDR_TOP = 0xfffff000;
  62 EXPORT_SYMBOL(__FIXADDR_TOP);
  63
  64 /*
  65  * vmalloc=size forces the vmalloc area to be exactly 'size'
  66  * bytes. This can be used to increase (or decrease) the
  67  * vmalloc area - the default is 128m.
  68  */
  69 static int __init parse_vmalloc(char *arg)
  70 {
  71         if (!arg)
  72                 return -EINVAL;
  73
  74         /* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
  75         __VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
  76         return 0;
  77 }
  78 early_param("vmalloc", parse_vmalloc);
  79
  80 /*
  81  * reservetop=size reserves a hole at the top of the kernel address space which
  82  * a hypervisor can load into later.  Needed for dynamically loaded hypervisors,
  83  * so relocating the fixmap can be done before paging initialization.
  84  */
  85 static int __init parse_reservetop(char *arg)
  86 {
  87         unsigned long address;
  88
  89         if (!arg)
  90                 return -EINVAL;
  91
  92         address = memparse(arg, &arg);
  93         reserve_top_address(address);
  94         early_ioremap_init();
  95         return 0;
  96 }
  97 early_param("reservetop", parse_reservetop);