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lkm: add is2mb, no usage yet

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twoneis 2025-04-10 23:25:44 +02:00
parent 0d4b45391a
commit 182c517c5a
1 changed files with 44 additions and 0 deletions
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44
code/lkm.c
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@ -1,9 +1,11 @@
#include <asm/pgtable_64.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/uaccess.h>
#include <stddef.h>
#define DEVICE_NAME "lkm"
#define CLASS_NAME "lkmclass"
@ -25,6 +27,48 @@ static struct file_operations lkm_fops = {
.unlocked_ioctl = lkm_ioctl,
};
void
is2mb(size_t addr)
{
unsigned long above = ((long)addr) >> __VIRTUAL_MASK_SHIFT;
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
if (above != 0 && above != -1UL)
return 0;
pgd = pgd_offset_pgd(_init_top_pgt, addr);
if (pgd_none(*pgd))
return 0;
p4d = p4d_offset(pgd, addr);
if (!p4d_present(*p4d))
return 0;
pud = pud_offset(p4d, addr);
if (!pud_present(*pud))
return 0;
if (pud_large(*pud))
return 0;
pmd = pmd_offset(pud, addr);
if (!pmd_present(*pmd))
return 0;
if (pmd_large(*pmd))
return 1;
pte = pte_offset_kernel(pmd, addr);
if (pte_none(*pte))
return 0;
return 0;
}
static int
lkm_init(void)
{