LXR linux/arch/x86/mm/pgtable

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/sched.h>
   3#include <linux/kernel.h>
   4#include <linux/errno.h>
   5#include <linux/mm.h>
   6#include <linux/nmi.h>
   7#include <linux/swap.h>
   8#include <linux/smp.h>
   9#include <linux/highmem.h>
  10#include <linux/pagemap.h>
  11#include <linux/spinlock.h>
  12
  13#include <asm/cpu_entry_area.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#include <linux/vmalloc.h>
  20
  21unsigned 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 */ 
  27void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
  28{
  29        pgd_t *pgd;
  30        p4d_t *p4d;
  31        pud_t *pud;
  32        pmd_t *pmd;
  33        pte_t *pte;
  34
  35        pgd = swapper_pg_dir + pgd_index(vaddr);
  36        if (pgd_none(*pgd)) {
  37                BUG();
  38                return;
  39        }
  40        p4d = p4d_offset(pgd, vaddr);
  41        if (p4d_none(*p4d)) {
  42                BUG();
  43                return;
  44        }
  45        pud = pud_offset(p4d, vaddr);
  46        if (pud_none(*pud)) {
  47                BUG();
  48                return;
  49        }
  50        pmd = pmd_offset(pud, vaddr);
  51        if (pmd_none(*pmd)) {
  52                BUG();
  53                return;
  54        }
  55        pte = pte_offset_kernel(pmd, vaddr);
  56        if (!pte_none(pteval))
  57                set_pte_at(&init_mm, vaddr, pte, pteval);
  58        else
  59                pte_clear(&init_mm, vaddr, pte);
  60
  61        /*
  62         * It's enough to flush this one mapping.
  63         * (PGE mappings get flushed as well)
  64         */
  65        flush_tlb_one_kernel(vaddr);
  66}
  67
  68unsigned long __FIXADDR_TOP = 0xfffff000;
  69EXPORT_SYMBOL(__FIXADDR_TOP);
  70
  71/*
  72 * vmalloc=size forces the vmalloc area to be exactly 'size'
  73 * bytes. This can be used to increase (or decrease) the
  74 * vmalloc area - the default is 128m.
  75 */
  76static int __init parse_vmalloc(char *arg)
  77{
  78        if (!arg)
  79                return -EINVAL;
  80
  81        /* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
  82        __VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
  83        return 0;
  84}
  85early_param("vmalloc", parse_vmalloc);
  86
  87/*
  88 * reservetop=size reserves a hole at the top of the kernel address space which
  89 * a hypervisor can load into later.  Needed for dynamically loaded hypervisors,
  90 * so relocating the fixmap can be done before paging initialization.
  91 */
  92static int __init parse_reservetop(char *arg)
  93{
  94        unsigned long address;
  95
  96        if (!arg)
  97                return -EINVAL;
  98
  99        address = memparse(arg, &arg);
 100        reserve_top_address(address);
 101        early_ioremap_init();
 102        return 0;
 103}
 104early_param("reservetop", parse_reservetop);
 105